HIGH VOLTAGE SOLAR PANEL

FIELD OF THE INVENTION

The invention relates generally to solar cell modules in which the solar cells are arranged in a shingled manner.

BACKGROUND

Alternate sources of energy are needed to satisfy ever increasing world-wide energy demands. Solar energy resources are sufficient in many geographical regions to satisfy such demands, in part, by provision of electric power generated with solar (e.g., photovoltaic) cells.

SUMMARY

In one aspect, a solar module comprises a number N greater than or equal to about 150 of rectangular or substantially rectangular silicon solar cells arranged as a plurality of super cells in two or more parallel rows. Each super cell comprises a plurality of the silicon solar cells arranged in line with long sides of adjacent silicon solar cells overlapping and conductively bonded to each other to electrically connect the silicon solar cells in series. The super cells are electrically connected to provide a high direct current voltage of greater than or equal to about 90 volts.

In one variation the solar module comprises one or more flexible electrical interconnects arranged to electrically connect the plurality of super cells in series to provide the high direct current voltage. The solar module may comprise module level power electronics including an inverter that converts the high direct current voltage to an alternating current voltage. The module level power electronics may sense the high direct current voltage and may operate the module at an optimum current-voltage power point.

In another variation the solar module comprises module level power electronics electrically connected to individual pairs of adjacent series connected rows of super cells, electrically connecting one or more of the pairs of rows of super cells in series to provide the high direct current voltage, and comprising an inverter that converts the high direct current voltage to an alternating current voltage. Optionally, the module level power electronics may sense the voltage across each individual pair of rows of super cells and may operate each individual pair of rows of super cells at an optimum current-voltage power point. Optionally, the module level power electronics may switch an individual pair of rows of super cells out of a circuit providing the high direct current voltage if the voltage across the pair of rows is below a threshold value.

In another variation the solar module comprises module level power electronics electrically connected to each individual row of super cells, electrically connecting two or more of the rows of super cells in series to provide the high direct current voltage, and comprising an inverter that converts the high direct current voltage to an alternating current voltage. Optionally, the module level power electronics may sense the voltage across each individual row of super cells and may operate each individual row of super cells at an optimum current-voltage power point. Optionally, the module level power electronics may switch an individual row of super cells out of a circuit providing the high direct current voltage if the voltage across the row of super cells is below a threshold value.

In another variation the solar module comprises module level power electronics electrically connected to each individual super cell, electrically connecting two or more of the super cells in series to provide the high direct current voltage, and comprising an inverter that converts the high direct current voltage to an alternating current voltage. Optionally, the module level power electronics may sense the voltage across each individual super cell and may operate each individual super cell at an optimum current-voltage power point. Optionally, the module level power electronics may switch an individual super cell out of a circuit providing the high direct current voltage if the voltage across the super cell is below a threshold value.

In another variation each super cell in the module is electrically segmented into a plurality of segments by hidden taps. The solar module comprises module level power electronics electrically connected to each segment of each super cell through the hidden taps, electrically connecting two or more segments in series to provide the high direct current voltage, and comprising an inverter that converts the high direct current voltage to an alternating current voltage. Optionally, the module level power electronics may sense the voltage across each individual segment of each super cell and may operate each individual segment at an optimum current-voltage power point. Optionally, the module level power electronics may switch an individual segment out of a circuit providing the high direct current voltage if the voltage across the segment is below a threshold value.

In any of the above variations the optimum current-voltage power point may be a maximum current-voltage power point.

In any of the above variations the module level power electronics may lack a direct current to direct current boost component.

In any of the above variations N may be greater than or equal to about 200, greater than or equal to about 250, greater than or equal to about 300, greater than or equal to about 350, greater than or equal to about 400, greater than or equal to about 450, greater than or equal to about 500, greater than or equal to about 550, greater than or equal to about 600, greater than or equal to about 650, or greater than or equal to about 700.

In any of the above variations the high direct current voltage may be greater than or equal to about 120 volts, greater than or equal to about 180 volts, greater than or equal to about 240 volts, greater than or equal to about 300 volts, greater than or equal to about 360 volts, greater than or equal to about 420 volts, greater than or equal to about 480 volts, greater than or equal to about 540 volts, or greater than or equal to about 600 volts.

In another aspect, a solar photovoltaic system comprises two or more solar modules electrically connected in parallel, and an inverter. Each solar module comprises a number N greater than or equal to about 150 rectangular or substantially rectangular silicon solar cells arranged as a plurality of super cells in two or more parallel rows. Each super cell in each module comprises two or more of the silicon solar cells in that module arranged in line with long sides of adjacent silicon solar cells overlapping and conductively bonded to each other to electrically connect the silicon solar cells in series. In each module the super cells are electrically connected to provide a high voltage direct current module output of greater than or equal to about 90 volts. The inverter is electrically connected to the two or more solar modules to convert their high voltage direct current output to an alternating current.

Each solar module may comprise one or more flexible electrical interconnects arranged to electrically connect the super cells in the solar module in series to provide the solar module's high voltage direct current output.

The solar photovoltaic system may comprise at least a third solar module electrically connected in series with a first one of the two or more solar modules that are electrically connected in parallel. In such cases the third solar module may comprise a number N′ greater than or equal to about 150 rectangular or substantially rectangular silicon solar cells arranged as a plurality of super cells in two or more parallel rows. Each super cell in the third solar module comprises two or more of the silicon solar cells in that module arranged in line with long sides of adjacent silicon solar cells overlapping and conductively bonded to each other to electrically connect the silicon solar cells in series. In the third solar module the super cells are electrically connected to provide a high voltage direct current module output of greater than or equal to about 90 volts.

Variations comprising a third solar module electrically connected in series with a first one of the two or more solar modules, as just described, may also comprise at least a fourth solar module electrically connected in series with a second one of the two or more solar modules that are electrically connected in parallel. The fourth solar module may comprises a number N″ greater than or equal to about 150 rectangular or substantially rectangular silicon solar cells arranged as a plurality of super cells in two or more parallel rows. Each super cell in the fourth solar module comprises two or more of the silicon solar cells in that module arranged in line with long sides of adjacent silicon solar cells overlapping and conductively bonded to each other to electrically connect the silicon solar cells in series. In the fourth solar module the super cells are electrically connected to provide a high voltage direct current module output of greater than or equal to about 90 volts.

The solar photovoltaic system may comprise fuses and/or blocking diodes arranged to prevent a short circuit occurring in any one of the solar modules from dissipating power generated in the other solar modules.

The solar photovoltaic system may comprise positive and negative buses to which the two or more solar modules are electrically connected in parallel and to which the inverter is electrically connected. Alternatively, the solar photovoltaic system may comprise a combiner box to which the two or more solar modules are electrically connected by a separate conductor. The combiner box electrically connects the solar modules in parallel, and may optionally comprise fuses and/or blocking diodes arranged to prevent a short circuit occurring in any one of the solar modules from dissipating power generated in the other solar modules.

The inverter may be configured to operate the solar modules at a direct current voltage above a minimum value set to avoid reverse biasing a solar module.

The inverter may be configured to recognize a reverse bias condition occurring in one or more of the solar modules and operate the solar modules at a voltage that avoids the reverse bias condition.

The solar photovoltaic system may be positioned on a roof top.

In any of the above variations N, N′, and N″ may be greater than or equal to about 200, greater than or equal to about 250, greater than or equal to about 300, greater than or equal to about 350, greater than or equal to about 400, greater than or equal to about 450, greater than or equal to about 500, greater than or equal to about 550, greater than or equal to about 600, greater than or equal to about 650, or greater than or equal to about 700. N, N′, and N″ may have the same or different values.

In any of the above variations the high direct current voltage provided by a solar module may be greater than or equal to about 120 volts, greater than or equal to about 180 volts, greater than or equal to about 240 volts, greater than or equal to about 300 volts, greater than or equal to about 360 volts, greater than or equal to about 420 volts, greater than or equal to about 480 volts, greater than or equal to about 540 volts, or greater than or equal to about 600 volts.

In another aspect a solar photovoltaic system comprises a first solar module comprising a number N greater than or equal to about 150 rectangular or substantially rectangular silicon solar cells arranged as a plurality of super cells in two or more parallel rows. Each super cell comprises a plurality of the silicon solar cells arranged in line with long sides of adjacent silicon solar cells overlapping and conductively bonded to each other to electrically connect the silicon solar cells in series. The system also comprises an inverter. The inverter may be for example a microinverter integrated with the first solar module. The super cells in the first solar module are electrically connected to provide a high direct current voltage of greater than or equal to about 90 volts to the inverter, which converts the direct current to an alternating current.

The first solar module may comprise one or more flexible electrical interconnects arranged to electrically connect the super cells in the solar module in series to provide the solar module's high voltage direct current output.

The solar photovoltaic system may comprise at least a second solar module electrically connected in series with the first solar module. The second solar module may comprise a number N′ greater than or equal to about 150 rectangular or substantially rectangular silicon solar cells arranged as a plurality of super cells in two or more parallel rows. Each super cell in the second solar module comprises two or more of the silicon solar cells in that module arranged in line with long sides of adjacent silicon solar cells overlapping and conductively bonded to each other to electrically connect the silicon solar cells in series. In the second solar module the super cells are electrically connected to provide a high voltage direct current module output of greater than or equal to about 90 volts.

The inverter (e.g., microinverter) may lack a direct current to direct current boost component.

In any of the above variations N and N′ may be greater than or equal to about 200, greater than or equal to about 250, greater than or equal to about 300, greater than or equal to about 350, greater than or equal to about 400, greater than or equal to about 450, greater than or equal to about 500, greater than or equal to about 550, greater than or equal to about 600 greater than or equal to about 650, or greater than or equal to about 700. N and N′ may have the same or different values.

In any of the above variations, the high direct current voltage provided by a solar module may be greater than or equal to about 120 volts, greater than or equal to about 180 volts, greater than or equal to about 240 volts, greater than or equal to about 300 volts, greater than or equal to about 360 volts, greater than or equal to about 420 volts, greater than or equal to about 480 volts, greater than or equal to about 540 volts, or greater than or equal to about 600 volts.

In another aspect, a solar module comprises a number N greater than or equal to about 250 rectangular or substantially rectangular silicon solar cells arranged as a plurality of series-connected super cells in two or more parallel rows. Each super cell comprises a plurality of the silicon solar cells arranged in line with long sides of adjacent silicon solar cells overlapping and conductively bonded directly to each other with an electrically and thermally conductive adhesive to electrically connect the silicon solar cells in the super cell in series. The solar module comprises less than one bypass diode per 25 solar cells. The electrically and thermally conductive adhesive forms bonds between adjacent solar cells having a thickness perpendicular to the solar cells of less than or equal to about 50 micron and a thermal conductivity perpendicular to the solar cells greater than or equal to about 1.5 W/(meter-K).

The super cells may be encapsulated in a thermoplastic olefin layer between front and back sheets. The super cells and their encapsulant may be sandwiched between glass front and back sheets.

The solar module may comprise, for example, less than one bypass diode per 30 solar cells, or less than one bypass diode per 50 solar cells, or less than one bypass diode per 100 solar cells. The solar module may comprise, for example, no bypass diodes, or only a single bypass diode, or not more than three bypass diodes, or not more than six bypass diodes, or not more than ten bypass diodes.

The conductive bonds between overlapping solar cells may optionally provide mechanical compliance to the super cells accommodating a mismatch in thermal expansion between the super cells and the glass front sheet in a direction parallel to the rows for a temperature range of about −40° C. to about 100° C. without damaging the solar module.

In any of the above variations, N may be greater than or equal to about 300, greater than or equal to about 350, greater than or equal to about 400, greater than or equal to about 450, greater than or equal to about 500, greater than or equal to about 550, greater than or equal to about 600 greater than or equal to about 650, or greater than or equal to about 700.

A solar energy system may comprise the solar module of any of the above variations and an inverter (e.g., a microinverter) electrically connected to the solar module and configured to convert a DC output from the solar module to provide an AC output. The inverter may lack a DC to DC boost component. The inverter may be configured to operate the solar module at a direct current voltage above a minimum value set to avoid reverse biasing a solar cell. The minimum voltage value may be temperature dependent. The inverter may be configured to recognize a reverse bias condition and operate the solar module at a voltage that avoids the reverse bias condition. For example, the inverter may be configured to operate the solar module in a local maximum region of the solar module's voltage-current power curve to avoid the reverse bias condition.

In another aspect, a solar module comprises a number N greater than or equal to about 250 rectangular or substantially rectangular silicon solar cells arranged as a plurality of series-connected super cells in two or more parallel rows. Each super cell comprises a plurality of the silicon solar cells arranged in line with long sides of adjacent silicon solar cells overlapping and conductively bonded directly to each other with an electrically and thermally conductive adhesive to electrically connect the silicon solar cells in the super cell in series. The solar module comprises one or more bypass diodes. Each pair of adjacent parallel rows in the solar module is electrically connected by a bypass diode that is conductively bonded to a rear surface electrical contact on a centrally located solar cell in one row of the pair and conductively bonded to a rear surface electrical contact on an adjacent solar cell in the other row of the pair.

In any variation of the solar module, each pair of adjacent parallel rows may be electrically connected by at least one other bypass diode that is conductively bonded to a rear surface electrical contact on a solar cell in one row of the pair and conductively bonded to a rear surface electrical contact on an adjacent solar cell in the other row of the pair. In any variation, each pair of adjacent parallel rows is electrically connected by at least two, at least three, or at least four other bypass diodes that are conductively bonded to a rear surface electrical contact on a solar cell in one row of the pair and conductively bonded to a rear surface electrical contact on an adjacent solar cell in the other row of the pair.

In any of the above variations, electrically and thermally conductive adhesive may be used to form bonds between adjacent solar cells having a thickness perpendicular to the solar cells of less than or equal to about 50 micron and a thermal conductivity perpendicular to the solar cells greater than or equal to about 1.5 W/(meter-K). In any variation, the super cells may be encapsulated in a thermoplastic olefin layer between front and back glass sheets. Conductive bonds between overlapping solar cells may provide mechanical compliance to the super cells accommodating a mismatch in thermal expansion between the super cells and the glass front sheet in a direction parallel to the rows for a temperature range of about −40° C. to about 100° C. without damaging the solar module.

In any of the above variations, the super cells may be electrically connected to provide a high direct current voltage of greater than or equal to about 120 volts, greater than or equal to about 180 volts, greater than or equal to about 240 volts, greater than or equal to about 300 volts, greater than or equal to about 360 volts, greater than or equal to about 420 volts, greater than or equal to about 480 volts, greater than or equal to about 540 volts, or greater than or equal to about 600 volts. For example, N may be greater than or equal to about 250 volts, and the super cells electrically connected to provide a high direct current voltage of greater than or equal to about 120 volts. As another example, N may be greater than or equal to about 400 volts and the super cells electrically connected to provide a high direct current voltage of greater than or equal to about 240 volts.

A solar energy system may comprise the solar module and an inverter electrically connected to the solar module and configured to convert a DC output from the solar module to provide an AC output. In any variation, the inverter may lack a DC to DC boost component. The inverter may be configured to operate the solar module at a direct current voltage above a minimum value set to avoid reverse biasing a solar cell. In any variation, the minimum voltage value may be temperature dependent. The inverter may be configured to recognize a reverse bias condition and operate the solar module at a voltage that avoids the reverse bias condition. The inverter may be configured to operate the solar module in a local maximum region of the solar module's voltage-current power curve to avoid the reverse bias condition. The inverter may be or comprise a microinverter integrated with the solar module.

In any of the above variations of solar energy systems, N may be greater than or equal to about 300, greater than or equal to about 350, greater than or equal to about 400, greater than or equal to about 450, greater than or equal to about 500, greater than or equal to about 550, greater than or equal to about 600 greater than or equal to about 650, or greater than or equal to about 700.

In any of the above variations of solar energy systems, the super cells may be electrically connected to provide a high direct current voltage of greater than or equal to about 120 volts, greater than or equal to about 180 volts, greater than or equal to about 240 volts, greater than or equal to about 300 volts, greater than or equal to about 360 volts, greater than or equal to about 420 volts, greater than or equal to about 480 volts, greater than or equal to about 540 volts, or greater than or equal to about 600 volts. For example, N may be greater than or equal to about 250 volts, and the super cells electrically connected to provide a high direct current voltage of greater than or equal to about 120 volts. As another example, N may be greater than or equal to about 400 volts and the super cells electrically connected to provide a high direct current voltage of greater than or equal to about 240 volts.

In any variation of the solar energy systems, the solar modules may be arranged in an overlapping shingled manner with another solar module to which it is electrically connected in an overlapping region.

These and other embodiments, features and advantages of the present invention will become more apparent to those skilled in the art when taken with reference to the following more detailed description of the invention in conjunction with the accompanying drawings that are first briefly described.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a cross-sectional diagram of a string of series-connected solar cells arranged in a shingled manner with the ends of adjacent solar cells overlapping to form a shingled super cell.

FIG. 2 shows a diagram of an example rectangular solar module comprising a plurality of rectangular shingled super cells, with the long side of each super cell having a length of approximately the full length of the long side of the module. The super cells are arranged with their long sides parallel to the long sides of the module.

FIGS. 3A-3B show block diagrams for, respectively, a solar module providing a conventional DC voltage to a microinverter and a high voltage solar module as described herein providing a high DC voltage to a microinverter.

FIGS. 4A-5B show example physical layout and electrical schematics for example high voltage solar modules incorporating bypass diodes.

FIGS. 6A-9B show example architectures for module level power management of high voltage solar modules comprising shingled super cells.

FIG. 10 shows an example arrangement of six super cells in six parallel rows with ends of adjacent rows offset and interconnected in series by flexible electrical interconnects.

FIG. 11A shows example flexible interconnects that may be used to interconnect super cells in series or in parallel. Some of the examples exhibit patterning that increase their flexibility (mechanical compliance) along their long axes, along their short axes, or along their long axes and their short axes. FIG. 11A shows example stress-relieving long interconnect configurations that may be used in hidden taps to super cells as described herein or as interconnects to front or rear surface super cell terminal contacts. FIGS. 11B-1 and 11B-2 illustrate examples of out of-plane-stress relieving features. FIGS. 11B-1 and 11B-2 show an example long interconnect configuration that comprises out-of plane stress relieving features and that may be used in hidden taps to super cells or as interconnects to front or rear surface super cell terminal contacts.

FIG. 12A schematically illustrates a photovoltaic system comprising a plurality of high DC voltage shingled solar cell modules electrically connected in parallel with each other and to a string inverter. FIG. 12B shows the photovoltaic system of FIG. 12A deployed on a roof top.

FIGS. 13A-13D show arrangements of current limiting fuses and blocking diodes that may be used to prevent a high DC voltage shingled solar cell module having a short circuit from dissipating significant power generate in other high DC voltage shingled solar cell modules to which it is electrically connected in parallel.

FIGS. 14A-14B show example arrangements in which two or more high DC voltage shingled solar cell modules are electrically connected in parallel in a combiner box, which may include current limiting fuses and blocking diodes.

FIGS. 15A-15B each show a plot of current versus voltage and a plot of power versus voltage for a plurality of high DC voltage shingled solar cell modules electrically connected in parallel. The plots of FIG. 15A are for an example case in which none of the modules include a reverse biased solar cell. The plots of FIG. 15B are for an example case in which some of the modules include one or more reverse biased solar cells.

FIG. 16A illustrates an example of a solar module utilizing about 1 bypass diode per super cell. FIG. 16C illustrates an example of a solar module utilizing bypass diodes in a nested configuration. FIG. 16B illustrates an example configuration for a bypass diode connected between two neighboring super cells using a flexible electrical interconnect.

DETAILED DESCRIPTION

The following detailed description should be read with reference to the drawings, in which identical reference numbers refer to like elements throughout the different figures. The drawings, which are not necessarily to scale, depict selective embodiments and are not intended to limit the scope of the invention. The detailed description illustrates by way of example, not by way of limitation, the principles of the invention. This description will clearly enable one skilled in the art to make and use the invention, and describes several embodiments, adaptations, variations, alternatives and uses of the invention, including what is presently believed to be the best mode of carrying out the invention.

As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” include plural referents unless the context clearly indicates otherwise. Also, the term “parallel” is intended to mean “parallel or substantially parallel” and to encompass minor deviations from parallel geometries rather than to require that any parallel arrangements described herein be exactly parallel. The term “perpendicular” is intended to mean “perpendicular or substantially perpendicular” and to encompass minor deviations from perpendicular geometries rather than to require that any perpendicular arrangement described herein be exactly perpendicular. The term “rectangular” is intended to mean “rectangular or substantially rectangular” and to encompass minor deviations from rectangular shapes.

This specification discloses high-efficiency solar modules (i.e., solar panels) comprising narrow rectangular silicon solar cells arranged in a shingled manner and electrically connected in series to form super cells, with the super cells arranged in physically parallel rows in the solar module. The super cells may have lengths spanning essentially the full length or width of the solar module, for example, or two or more super cells may be arranged end-to-end in a row. Each super cell may include any number of solar cells, including in some variations at least nineteen solar cells and in certain variations greater than or equal to 100 silicon solar cells, for example. Each solar module may have a conventional size and shape and yet include hundreds of silicon solar cells, allowing the super cells in a single solar module to be electrically interconnected to provide a direct current (DC) voltage of for example, about 90 Volts (V) to about 450 V or more.

As further described below, this high DC voltage facilitates conversion from direct to alternating current (AC) by an inverter (e.g., microinverter located on the solar module) by eliminating or reducing the need for a DC to DC boost (step-up in DC voltage) prior to conversion to AC by the inverter. Also as further described below, the high DC voltage also facilitates the use of arrangements in which DC/AC conversion is performed by a central inverter receiving high voltage DC output from two or more high voltage shingled solar cell modules electrically connected in parallel with each other.

Turning now to the figures for a more detailed understanding of the solar modules described in this specification, FIG. 1 shows a cross-sectional view of a string of series-connected solar cells 10 arranged in a shingled manner with the ends of adjacent solar cells overlapping and electrically connected to form a super cell 100. Each solar cell 10 comprises a semiconductor diode structure and electrical contacts to the semiconductor diode structure by which electric current generated in solar cell 10 when it is illuminated by light may be provided to an external load.

In the examples described in this specification, each solar cell 10 is a rectangular crystalline silicon solar cell having front (sun side) surface and rear (shaded side) surface metallization patterns providing electrical contact to opposite sides of an n-p junction, the front surface metallization pattern is disposed on a semiconductor layer of n-type conductivity, and the rear surface metallization pattern is disposed on a semiconductor layer of p-type conductivity. However, other material systems, diode structures, physical dimensions, or electrical contact arrangements may be used if suitable. For example, the front (sun side) surface metallization pattern may be disposed on a semiconductor layer of p-type conductivity, and the rear (shaded side) surface metallization pattern disposed on a semiconductor layer of n-type conductivity.

Referring again to FIG. 1, in super cell 100 adjacent solar cells 10 are conductively bonded to each other in the region in which they overlap by an electrically conducting bonding material that electrically connects the front surface metallization pattern of one solar cell to the rear surface metallization pattern of the adjacent solar cell. Suitable electrically conducting bonding materials may include, for example, electrically conducting adhesives and electrically conducting adhesive films and adhesive tapes, and conventional solders.

FIG. 2 shows an example rectangular solar module 200 comprising six rectangular super cells 100, each of which has a length approximately equal to the length of the long sides of the solar module. The super cells are arranged as six parallel rows with their long sides oriented parallel to the long sides of the module. A similarly configured solar module may include more or fewer rows of such side-length super cells than shown in this example. In other variations the super cells may each have a length approximately equal to the length of a short side of a rectangular solar module, and be arranged in parallel rows with their long sides oriented parallel to the short sides of the module. In yet other arrangements each row may comprise two or more super cells electrically interconnected in series. The modules may have shorts sides having a length, for example, of about 1 meter and long sides having a length, for example, of about 1.5 to about 2.0 meters. Any other suitable shapes (e.g., square) and dimensions for the solar modules may also be used.

In some variations, the conductive bonds between overlapping solar cells provide mechanical compliance to the super cells accommodating a mismatch in thermal expansion between the super cells and a glass front sheet of the solar module in a direction parallel to the rows for a temperature range of about −40° C. to about 100° C. without damaging the solar module.

Each super cell in the illustrated example comprises 72 rectangular solar cells each having a width equal or approximately equal to ⅙ the width of a conventionally sized 156 mm square or pseudo square silicon wafer and a length equal or approximately equal to the width of the square or pseudo square waver. More, generally, rectangular silicon solar cells employed in the solar modules described herein may have lengths, for example, equal to or approximately equal to the width of a conventionally sized square or pseudo square silicon wafer and widths, for example, equal to or approximately equal to 1/M the width of a conventionally sized square or pseudo square waver, with M any integer ≦20. M may be for example 3, 4, 5, 6 or 12. M may also be greater than 20. A super cell may comprise any suitable number of such rectangular solar cells.

The super cells in solar module 200 may be interconnected in series by electrical interconnects (optionally, flexible electrical interconnects) or by module level power electronics as described below to provide from a conventionally sized solar module a higher than conventional voltage, because the shingling approach just described incorporates many more cells per module than is conventional. For example, a conventionally sized solar module comprising super cells made from ⅛th cut silicon solar cells may comprise over 600 solar cells per module. In comparison, a conventionally sized solar module comprising conventionally sized and interconnected silicon solar cells typically comprises about 60 solar cells per module. In conventional silicon solar modules, square or pseudo square solar cells are typically interconnected by copper ribbons and spaced apart from each other to accommodate the interconnections. In such cases, cutting the conventionally sized square or pseudo square wafers into narrow rectangles would reduce the total amount of active solar cell area in the module and therefore reduce module power because of the additional cell-to-cell interconnects required. In contrast, in the solar modules disclosed herein the shingled arrangement hides cell-to-cell electrical interconnections beneath active solar cell area. Consequently the solar modules described herein may provide high output voltages without reducing module output power because there is little or no tradeoff between module power and the number of solar cells (and required cell-to-cell interconnections) in the solar module.

When all the solar cells are connected in series, a shingled solar cell module as described herein may provide a DC voltage in the range of about 90 volts to about 450 Volts or more, for example. As noted above, this high DC voltage may be advantageous.

For example, a microinverter disposed on or near a solar module may be used for module level power optimization and DC to AC conversion. Referring now to FIGS. 3A-3B, conventionally a microinverter 310 receives a 25 V to 40 V DC input from a single solar module 300 and outputs a 230 V AC output to match the connected grid. The microinverter typically comprises two major components, a DC/DC boost and DC/AC inversion. The DC/DC boost is utilized to increase the DC bus voltage needed for the DC/AC conversion, and is typically the most expensive and lossy (2% efficiency loss) component. Because the solar modules described herein provide a high voltage output, the need for a DC/DC boost may be reduced or eliminated (FIG. 3B). This may reduce cost and increase efficiency and reliability of the solar module.

In conventional arrangements using a central (“string”) inverter rather than microinverters, conventional low DC output solar modules are electrically connected in series with each other and to the string inverter. The voltage produced by the string of solar modules is equal to the sum of the individual module voltages, because the modules are connected in series. A permissible voltage range determines the maximum and minimum number of modules in the string. The maximum number of modules is a set by the module voltage and the code voltage limits: for example N_max×V_oc<600 V(US residential standard) or N_max×V_oc<1,000 V (commercial standard). The minimum number of modules in the series is set by the module voltage and the minimum operating voltage required by the string inverter: N_min×V_mp>V_Invertermin. The minimum operating voltage (V_invertermin) required by the string inverter (e.g., a Fronius, Powerone, or SMA inverter) is typically between about 180 V and about 250 V. Typically, the optimal operating voltage for the string inverter is about 400 V.

A single high DC voltage shingled solar cell module as described herein may produce a voltage greater than the minimum operating voltage required by a string inverter, and optionally at or near the optimum operating voltage for the string inverter. As a consequence, the high DC voltage shingled solar cell modules described herein may be electrically connected in parallel with each other to a string inverter. This avoids the string length requirements of series connected module strings, which can complicate system design and installation. Also, in a series connected string of solar modules the lowest current module dominates, and the system cannot operate efficiently if different modules in the string receive different illumination as may occur for modules on different roof slopes or as a result of tree shade. The parallel high voltage module configurations described herein may avoid these problems as well, because the current through each solar module is independent from the current through the other solar modules. Further, such arrangements need not require module level power electronics and thus may improve reliability of the solar modules, which may be particularly important in variations in which the solar modules are deployed on a roof top.

Referring now to FIGS. 4A-4B, as described above, a super cell may run approximately the full length or width of the solar module. To enable electrical connections along the length of the super cell, a hidden (from front view) electrical tapping point may be integrated into the solar module construction. This may be accomplished by connecting an electrical conductor to the back surface metallization of a solar cell at an end or intermediate location in the super cell. Such hidden taps allow electrical segmentation of a super cell, and enable interconnection of super cells or segments of super cells to bypass diodes, module level power electronics (e.g. a microinverter, power optimizers, voltage intelligence and smart switches, and related devices), or other components. The use of hidden taps and particular examples of hidden tap configurations are further described in U.S. patent application Ser. No. 14/674,983, U.S. Provisional Patent Application No. 62/081,200, and U.S. Provisional Patent Application No. 62/113,250, each of which has been incorporated herein by reference in its entirety for all purposes.

In the examples of FIG. 4A (an example physical layout) and FIG. 4B (an example electrical schematic), the illustrated solar modules 200 each comprise six super cells 100 electrically connected in series to provide a high DC voltage. Each super cell is electrically segmented into several groups of solar cells by hidden taps 400, with each group of solar cells electrically connected in parallel with a different bypass diode 410. In these examples the bypass diodes are disposed within the solar module laminate structure, i.e., with the solar cells in an encapsulant between a front surface transparent sheet and a backing sheet. Alternatively, the bypass diodes may be disposed in a junction box located on a rear surface or edge of the solar module, and interconnected to the hidden taps by conductor runs.

In the examples of FIG. 5A (physical layout) and FIG. 5B (corresponding electrical schematic), the illustrated solar module 200 also comprises six super cells 100 electrically connected in series to provide a high DC voltage. In this example, the solar module is electrically segmented into three pairs of series connected super cells, with each pair of super cells electrically connected in parallel with a different bypass diode. In this example the bypass diodes are disposed within a junction box 500 located on a back surface of the solar module. The bypass diodes could instead be located in the solar module laminate structure or in an edge-mounted junction box.

In the examples of FIGS. 4A-5B, in normal operation of the solar module each solar cell is forward biased and all bypass diodes are therefore reverse biased and not conducting. If one or more solar cells in a group is reverse biased to a sufficiently high voltage, however, the bypass diode corresponding to that group will turn on and current flow through the module will bypass the reverse-biased solar cells. This prevents the formation of dangerous hot spots at shaded or malfunctioning solar cells.

Alternatively, the bypass diode functionality can be accomplished within module level power electronics, e.g. a microinverter, disposed on or near the solar module. (Module level power electronics and their use may also be referred to herein as module level power management devices or systems and module level power management). Such module level power electronics, optionally integrated with the solar module, may optimize the power from groups of super cells, from each super cell, or from each individual super cell segment in electrically segmented super cells (e.g., by operating the group of super cells, super cell, or super cell segment at its maximum power point), thereby enabling discrete power optimization within the module. The module level power electronics may eliminate the need for any bypass diodes within the module as the power electronics may determine when to bypass the entire module, a specific group of super cells, one or more specific individual super cells, and/or one or more specific super cell segments.

This may be accomplished, for example, by integrating voltage intelligence at the module level. By monitoring the voltage output of a solar cell circuit (e.g., one or more super cells or super cell segments) in the solar module, a “smart switch” power management device can determine if that circuit includes any solar cells in reverse bias. If a reverse biased solar cell is detected, the power management device can disconnect the corresponding circuit from the electrical system using, for example, a relay switch or other component. For example, if the voltage of a monitored solar cell circuit drops below a predetermined threshold, then the power management device will shut off (open circuit) that circuit. The predetermined threshold may be, for example a certain percentage or magnitude (e.g. 20% or 10V) compared to normal operation of the circuit Implementation of such voltage intelligence may be incorporated into existing module level power electronics products (e.g., from Enphase Energy Inc., Solaredge Technologies, Inc., Tigo Energy, Inc.) or through a custom circuit design.

FIG. 6A (physical layout) and FIG. 6B (corresponding electrical schematic) show an example architecture for module level power management of a high voltage solar module comprising shingled super cells. In this example, rectangular solar module 200 comprises six rectangular shingled super cells 100 arranged in six rows extending the length of the long sides of the solar module. The six super cells are electrically connected in series to provide a high DC voltage. Module level power electronics 600 may perform voltage sensing, power management, and/or DC/AC conversion for the entire module.

FIG. 7A (physical layout) and FIG. 7B (corresponding electrical schematic) show another example architecture for module level power management of a high voltage solar module comprising shingled super cells. In this example, rectangular solar module 200 comprises six rectangular shingled super cells 100 arranged in six rows extending the length of the long sides of the solar module. The six super cells are electrically grouped into three pairs of series connected super cells. Each pair of super cells is individually connected to module level power electronics 600, which may perform voltage sensing and power optimization on the individual pairs of super cells, connect two or more of them in series to provide a high DC voltage, and/or perform DC/AC conversion.

FIG. 8A (physical layout) and FIG. 8B (corresponding electrical schematic) show another example architecture for module level power management of a high voltage solar module comprising shingled super cells. In this example, rectangular solar module 200 comprises six rectangular shingled super cells 100 arranged in six rows extending the length of the long sides of the solar module. Each super cell is individually connected with module level power electronics 600, which may perform voltage sensing and power optimization on each super cell, connect two or more of them in series to provide a high DC voltage, and/or perform DC/AC conversion.

FIG. 9A (physical layout) and FIG. 9B (corresponding electrical schematic) show another example architecture for module level power management of a high voltage solar module comprising shingled super cells. In this example, rectangular solar module 200 comprises six rectangular shingled super cells 100 arranged in six rows extending the length of the long sides of the solar module. Each super cell is electrically segmented into two or more groups of solar cells by hidden taps 400. Each resulting group of solar cells is individually connected with module level power electronics 600, which may perform voltage sensing and power optimization on each solar cell group, connect a plurality of the groups in series to provide a high DC voltage, and/or perform DC/AC conversion.

In some variations two or more high voltage DC shingled solar cell modules as described herein are electrically connected in series to provide a high voltage DC output, which is converted to AC by an inverter. The inverter may be a microinverter integrated with one of the solar modules, for example. In such cases the microinverter may optionally be a component of module level power management electronics that also perform additional sensing and connecting functions as described above. Alternatively the inverter may be a central “string” inverter as further discussed below.

As shown in FIG. 10, when stringing super cells in series in a solar module adjacent rows of super cells may be slightly offset along their long axes in a staggered manner. This staggering allows adjacent ends of super cell rows to be electrically connected in series by an interconnect 700 bonded to the top of one super cell and to the bottom of the other, while saving module area (space/length) as well as streamlining manufacturing. Adjacent rows of super cells may be offset by about 5 millimeters, for example.

Differential thermal expansion between electrical interconnects 700 and silicon solar cells and the resulting stress on the solar cell and the interconnect can lead to cracking and other failure modes that can degrade performance of the solar module. Consequently, it is desirable that the interconnect be flexible and configured to accommodate such differential expansion without significant stress developing. The interconnect may provide stress and thermal expansion relief by, for example, being formed from highly ductile materials (e.g., soft copper, thin copper sheet), being formed from low thermal expansion coefficient materials (e.g., Kovar, Invar or other low thermal expansion iron-nickel alloys) or from materials having a thermal expansion coefficient approximately matching that of silicon, incorporating in-plane geometric expansion features such as slits, slots, holes, or truss structures that accommodate differential thermal expansion between the interconnect and the silicon solar cell, and/or employing out-of-plane geometric features such as kinks, jogs, or dimples that accommodate such differential thermal expansion. Conductive portions of the interconnects may have a thickness of, for example, less than about 100 microns, less than about 50 microns, less than about 30 microns, or less than about 25 microns to increase the flexibility of the interconnects. (The generally low current in these solar modules enables use of thin flexible conductive ribbons without excessive power loss resulting from the electrical resistance of the thin interconnects).

In some variations conductive bonds between a super cell and a flexible electrical interconnect force the flexible electrical interconnect to accommodate a mismatch in thermal expansion between the super cell and the flexible electrical interconnect for a temperature range of about −40° C. to about 180° C. without damaging the solar module.

FIGS. 11A shows several example interconnect configurations, designated by reference numerals 400A-400T, that employ in-plane stress-relieving geometrical features and may be suitable for electrically interconnecting super cells in series to provide a high DC voltage, as described herein. Example interconnect 400U shown in the in-plane (x-y) view of FIG. 11B-1 and in the out-of-plane (x-z) view of FIG. 11B-2 employs bends 3705 as out of-plane-stress relieving features in a thin metal ribbon. Bends 3705 reduce the apparent tensile stiffness of the metal ribbon. The bends allow the ribbon material to locally bend instead of only elongating when the ribbon is under tension. For thin ribbons, this can significantly reduce the apparent tensile stiffness by, for example, 90% or more. The exact amount of apparent tensile stiffness reduction depends on several factors, including the number of bends, geometry of the bends, and the thickness of the ribbon. An interconnect may also employ in-plane and out-of-plane stress-relieving features in combination.

The discussion with respect to FIGS. 6A-9B focused on module level power management, with possible DC/AC conversion of a high DC module voltage by module level power electronics to provide an AC output from the module. As noted above, DC/AC conversion of high DC voltages from shingled solar cell modules as described herein may be performed instead by a central string inverter. For example, FIG. 12A schematically illustrates a photovoltaic system 800 that comprises a plurality of high DC voltage shingled solar cell modules 200 electrically connected in parallel with each other to a string inverter 815 via a high DC voltage negative bus 820 and a high DC voltage positive bus 810. Typically, each solar module 200 comprises a plurality of shingled super cells electrically connected in series with electrical interconnects to provide a high DC voltage, as described above. Solar modules 200 may optionally comprise bypass diodes arranged as described above, for example. FIG. 12B shows an example deployment of photovoltaic system 800 on a roof top.

In some variations of photovoltaic system 800, two or more short series connected strings of high DC voltage shingled solar cell modules may be electrically connected in parallel with a string inverter. Referring again to FIG. 12A, for example, each solar module 200 may be replaced with a series connected string of two or more high DC voltage shingled solar cell modules 200. This might be done, for example, to maximize the voltage provided to the inverter while complying with regulatory standards.

Conventional solar modules typically produce about 8 amps Isc (short circuit current), about 50 Voc (open circuit voltage), and about 35 Vmp (maximum power point voltage). As discussed above, high DC voltage shingled solar cell modules as described herein comprising M times the conventional number of solar cells, with each of the solar cells having an area of about 1/M the area of a conventional solar cell, produce roughly M times higher voltage and 1/M the current of a conventional solar module. As noted above M can be any suitable integer, is typically ≦20, but may be greater than 20. M may be for example 3, 4, 5, 6, or 12.

If M=6, Voc for the high DC voltage shingled solar cell modules may be for example about 300 V. Connecting two such modules in series would provide about 600 V DC to the bus, complying with the maximum set by US residential standards. If M=4, Voc for the high DC voltage shingled solar cell modules may be for example about 200 V. Connecting three such modules in series would provide about 600 V DC to the bus. If M=12, Voc for the high DC voltage shingled solar cell modules may be for example about 600 V. One could also configure the system to have bus voltages less than 600 V. In such variations the high DC voltage shingled solar cell modules may be, for example, connected in pairs or triplets or any other suitable combination in a combiner box to provide an optimal voltage to the inverter.

A challenge arising from the parallel configuration of high DC voltage shingled solar cell modules described above is that if one solar module has a short circuit the other solar modules could potentially dump their power on the shorted module (i.e., drive current through and dissipate power in the shorted module) and create a hazard. This problem can be averted, for example, by use of blocking diodes arranged to prevent other modules from driving current through a shorted module, use of current limiting fuses, or use of current limiting fuses in combination with blocking diodes. FIG. 12B schematically indicates the use of two current limiting fuses 830 on the positive and negative terminals of a high DC voltage shingled solar cell module 200.

The protective arrangement of blocking diodes and/or fuses may depend on whether or not the inverter comprises a transformer. Systems using an inverter comprising a transformer typically ground the negative conductor. Systems using a transformerless inverter typically do not ground the negative conductor. For a transformerless inverter, it may be preferable to have a current limiting fuse in-line with the positive terminal of the solar module and another current limiting fuse in line with the negative terminal.

Blocking diodes and/or current limiting fuses may be placed, for example, with each module in a junction box or in the module laminate. Suitable junction boxes, blocking diodes (e.g., in-line blocking diodes), and fuses (e.g., in-line fuses) may include those available from Shoals Technology Group.

FIG. 13A shows an example high voltage DC shingled solar cell module comprising a junction box 840 in which a blocking diode 850 is in line with the positive terminal of the solar module. The junction box does not include a current limiting fuse. This configuration may preferably be used in combination with one or more current limiting fuses located elsewhere (for example in a combiner box) in line with the positive and/or negative terminals of the solar module (e.g., see FIG. 13D below). FIG. 13B shows an example high voltage DC shingled solar cell module comprising a junction box 840 in which a blocking diode is in line with the positive terminal of the solar module and a current limiting fuse is in line with the negative terminal. FIG. 13C shows an example high voltage DC shingled solar cell module comprising a junction box 840 in which a current limiting fuse is in line with the positive terminal of the solar module and another current limiting fuse is in line with the negative terminal. FIG. 13D shows an example high voltage DC shingled solar cell module comprising a junction box 840 configure as in FIG. 13A, and fuses located outside of the junction box in line with the positive and negative terminals of the solar module.

Referring now to FIGS. 14A-14B, as an alternative to the configurations described above, blocking diodes and/or current limiting fuses for all of the high DC voltage shingled solar cell modules may be placed together in a combiner box 860. In these variations one or more individual conductors run separately from each module to the combiner box. As shown in FIG. 14A, in one option a single conductor of one polarity (e.g., negative as illustrated) is shared between all modules. In another option (FIG. 14B) both polarities have individual conductors for each module. Although FIGS. 14A-14B show only fuses located in combiner box 860, any suitable combination of fuses and or blocking diodes may be located in the combiner box. In addition, electronics performing other functions such as, for example, monitoring, maximum power point tracking, and/or disconnecting of individual modules or groups of modules may be implemented in the combiner box.

Reverse bias operation of a solar module may occur when one or more solar cells in the solar module are shaded or otherwise generating low current, and the solar module is operated at a voltage-current point that drives a larger current through a low-current solar cell than the low-current solar cell can handle. A reverse biased solar cell may heat up and create a hazard condition. A parallel arrangement of high DC voltage shingled solar cell modules, as shown in FIG. 12A for example, may enable the modules to be protected from reverse bias operation by setting a suitable operating voltage for the inverter. This is illustrated for example by FIGS. 15A-15B.

FIG. 15A shows a plot 870 of current versus voltage and a plot 880 of power versus voltage for a parallel-connected string of about ten high DC voltage shingled solar modules. These curves were calculated for a model in which none of the solar modules included a reverse biased solar cell. Because the solar modules are electrically connected in parallel, they all have the same operating voltage and their currents add. Typically, an inverter will vary the load on the circuit to explore the power-voltage curve, identify the maximum point on that curve, then operate the module circuit at that point to maximize output power.

In contrast, FIG. 15B shows a plot 890 of current versus voltage and a plot 900 of power versus voltage for the model system of FIG. 15A for a case where some of the solar modules in the circuit include one or more reverse biased solar cells. The reverse-biased modules manifest themselves in the example current-voltage curve by the formation of a knee shape with a transition from about 10 amp operation at voltages down to about 210 volts to about 16 amp operation at voltages below about 200 volts. At voltages below about 210 volts the shaded modules include reverse biased solar cells. The reverse-biased modules also manifest themselves in the power-voltage curve by the existence of two maxima: an absolute maximum at about 200 volts and a local maximum at about 240 volts. The inverter may be configured to recognize such signs of reverse-biased solar modules and operate the solar modules at an absolute or local maximum power point voltage at which no modules are reverse biased. In the example of FIG. 15B, the inverter may operate the modules at the local maximum power point to ensure that no module is reverse biased. In addition, or alternatively, a minimum operating voltage may be selected for the inverter, below which it is unlikely that any modules will be reverse biased. That minimum operating voltage may be adjusted based on other parameters such as the ambient temperature, the operating current and the calculated or measured solar module temperature as well as other information received from outside sources, such as irradiance for example.

In some embodiments, the high DC voltage solar modules themselves can be shingled, with adjacent solar modules arranged in a partially overlapping manner and optionally electrically interconnected in their overlapping regions. Such shingled configurations may optionally be used for high voltage solar modules electrically connected in parallel that provide a high DC voltage to a string inverter, or for high voltage solar modules that each comprise a microinverter that converts the solar module's high DC voltage to an AC module output. A pair of high voltage solar modules may be shingled as just described and electrically connected in series to provide a desired DC voltage, for example.

Conventional string inverters often are required to have a fairly wide range of potential input voltage (or ‘dynamic range’) because 1) they must be compatible with different series-connected module string lengths, 2) some modules in a string may be fully or partially shaded, and 3) changes in ambient temperature and radiation change the module voltage. In systems employing parallel architecture as described herein the length of the string of parallel-connected solar modules does not affect voltage. Further, for the case where some modules are partially shaded and some are not one can decide to operate the system at the voltage of the non-shaded modules (e.g., as described above). Therefore the input voltage range of an inverter in a parallel-architecture system may need only accommodate the ‘dynamic range’ of factor #3—temperature and radiation changes. Because this is less, for example about 30% of the conventional dynamic range required of inverters, inverters employed with parallel architecture systems as described herein may have a narrower range of MPPT (maximum power point tracking), for example between about 250 volts at standard conditions and about 175 volts at high temperature and low radiation, or for example between about 450 volts at standard conditions and about 350 volts at high temperature and low radiation (in which case 450 volts MPPT operation may correspond to a V_OCunder 600 volts in lowest temperature operation). In addition, as described above the inverters may receive enough DC voltage to convert directly to AC without a boost phase. Consequently, string inverters employed with parallel architecture systems as described herein may be simpler, of lower cost, and operate at higher efficiencies than string inverters employed in conventional systems.

For both microinverters and string inverters employed with the high voltage direct current shingled solar cell modules described herein, to eliminate a DC boost requirement of the inverter it may be preferable to configure the solar module (or short series-connected string of solar modules) to provide an operating (e.g., maximum power point Vmp) DC voltage above the peak-to-peak of the AC. For example, for 120 V AC, peak-to peak is sqrt(2)*120V=170V. Hence the solar modules might be configured to provide a minimal Vmp of about 175 V, for example. The Vmp at standard conditions might then be about 212 V (assuming 0.35% negative voltage temperature coefficient and maximal operating temperature of 75° C.), and the Vmp at the lowest temperature operating condition (e.g., −15° C.) would then be about 242 V, and hence the Voc below about 300 V (depending on the module fill factor). For split phase 120 V AC (or 240 V AC) all of these numbers double, which is convenient as 600 V DC is the maximum permitted in the US for many residential applications. For commercial applications, requiring and permitting higher voltages, these numbers may be further increased.

A high voltage shingled solar cell module as described herein may be configured to operate at >600 V_OCor >1000 V_OC, in which case the module may comprise integrated power electronics that prevent the external voltage provided by the module from exceeding code requirements. Such an arrangement may enable the operating V_mpto be sufficient for split phase 120 V (240 V, requiring about 350 V) without a problem of V_OCat low temperatures exceeding 600 V.

When a building's connection to the electricity grid is disconnected, for example by firefighters, solar modules (e.g., on the building roof) providing electricity to the building can still generate power if the sun is shining. This raises a concern that such solar modules can keep the roof ‘live’ with a dangerous voltage after disconnection of the building from the grid. To address this concern, high voltage direct current shingled solar cell modules described herein may optionally include a disconnect, for example in or adjacent to a module junction box. The disconnect may be a physical disconnect or a solid state disconnect, for example. The disconnect may be configured for example to be “normally off”, so that when it loses a certain signal (e.g., from the inverter) it disconnects the solar module's high voltage output from the roof circuit. The communication to the disconnect may be, for example, over the high voltage cables, through a separate wire, or wireless.

A significant advantage of shingling for high-voltage solar modules is heat spreading between solar cells in a shingled super cell. Applicants have discovered that heat may be readily transported along a silicon super cell through thin electrically and thermally conductive bonds between adjacent overlapping silicon solar cells. The thickness of the electrically conductive bond between adjacent overlapping solar cells formed by the electrically conductive bonding material, measured perpendicularly to the front and rear surfaces of the solar cells, may be for example less than or equal to about 200 microns, or less than or equal to about 150 microns, or less than or equal to about 125 microns, or less than or equal to about 100 microns, or less than or equal to about 90 microns, or less than or equal to about 80 microns, or less than or equal to about 70 microns, or less than or equal to about 60 microns, or less than or equal to about 50 microns, or less than or equal to about 25 microns. Such a thin bond reduces resistive loss at the interconnection between cells, and also promotes flow of heat along the super cell from any hot spot in the super cell that might develop during operation. The thermal conductivity of the bond between solar cells may be, for example, >about 1.5 Watts/(meter K). Further, the rectangular aspect ratio of the solar cells typically employed herein provides extended regions of thermal contact between adjacent solar cells.

In contrast, in conventional solar modules employing ribbon interconnects between adjacent solar cells, heat generated in one solar cell does not readily spread through the ribbon interconnects to other solar cells in the module. That makes conventional solar modules more prone to developing hot spots than are solar modules described herein.

Furthermore, the current through a super cell in the solar modules described herein is typically less than that through a string of conventional solar cells, because the super cells described herein are typically formed by shingling rectangular solar cells each of which has an active area less than (for example, ⅙) that of a conventional solar cell.

As a consequence, in the solar modules disclosed herein less heat is dissipated in a solar cell reverse biased at the breakdown voltage, and the heat may readily spread through the super cell and the solar module without creating a dangerous hot spot.

Several additional and optional features may make high voltage solar modules employing super cells as described herein even more tolerant to heat dissipated in a reverse biased solar cell. For example, the super cells may be encapsulated in a thermoplastic olefin (TPO) polymer. TPO encapsulants are more photo-thermal stable than standard ethylene-vinyl acetate (EVA) encapsulants. EVA will brown with temperature and ultraviolet light and lead to hot spot issues created by current limiting cells. Further, the solar modules may have a glass-glass structure in which the encapsulated super cells are sandwiched between a glass front sheet and a glass back sheet. Such a glass-glass structure enables the solar module to safely operate at temperatures greater than those tolerated by a conventional polymer back sheet. Further still, junction boxes, if present, may be mounted on one or more edges of a solar module, rather than behind the solar module where a junction box would add an additional layer of thermal insulation to the solar cells in the module above it.

Applicants have therefore recognized that high voltage solar modules formed from super cells as described herein may employ far fewer bypass diodes than in conventional solar modules, because heat flow through the super cells may allow a module to operate without significant risk with one or more solar cells reverse biased. For example, in some variations high voltage solar modules as described herein employ less than one bypass diode per 25 solar cells, less than one bypass diode per 30 solar cells, less than one bypass diode per 50 solar cell, less than one bypass diode per 75 solar cells, less than one bypass diode per 100 solar cells, only a single bypass diode, or no bypass diode.

FIGS. 16A-16C illustrate additional example high voltage solar modules utilizing bypass diodes. As noted above, when a portion of a solar module is shaded, damage to the module may be prevented or reduced through the use of bypass diodes. For the example solar module 4700 shown in FIG. 16A, 10 super cells 100 are connected in series. Any other suitable number of super cells may also be used. As illustrated, the 10 super cells are arranged in parallel rows. Each super cell contains 40 series connected solar cells 10, where each of the 40 solar cells is made from approximately ⅙ of a square or pseudo-square, as described herein. Any other suitable number of solar cells of any suitable dimensions may also be used. Under normal unshaded operation, current flows in from junction box 4716 through each of the super cells 100 connected in series through connectors 4715, and then current flows out through junction box 4717. Optionally, a single junction box may be used instead of separate junction boxes 4716 and 4717, so that current returns to one junction box. The example shown in FIG. 16A shows an implementation with approximately one bypass diode per super cell. As shown, a single bypass diode is electrically connected between a pair of neighboring super cells at a point approximately midway along the super cells (e.g., a single bypass diode 4901A is electrically connected between the 22^ndsolar cell of the first super cell and its neighboring solar cell in the second super cell, a second bypass diode 4901B is electrically connected between the second super cell and the third super cell, and so forth). The first and last strings of cells have only approximately half the number of solar cells in a super cell per bypass diode. For the example shown in FIG. 16A, the first and last strings of cells include only 22 cells per bypass diode. The total number of bypass diodes (11) for the variation of high voltage solar module illustrated in FIG. 16A is equal to the number of super cells plus 1 additional bypass diode.

Each bypass diode may be incorporated into a flex circuit, for example. Referring now to FIG. 16B, an expanded view of a bypass diode connected region of two neighboring super cells is shown. The view for FIG. 16B is from the non-sunny side. As shown, two solar cells 10 on neighboring super cells are electrically connected using a flex circuit 4718 comprising a bypass diode 4720. Flex circuit 4718 and bypass diode 4720 are electrically connected to the solar cells 10 using contact pads 4719 located on the rear surfaces of the solar cells. (See also further discussion of the use of hidden contact pads to provide hidden taps to bypass diodes and particular examples of hidden tap configurations in U.S. patent application Ser. No. 14/674,983, U.S. Provisional Patent Application No. 62/081,200, and U.S. Provisional Patent Application No. 62/113,250, each of which has been incorporated herein by reference in its entirety for all purposes.) Additional bypass diode electrical connection schemes may be employed to reduce the number of solar cells per bypass diode. One example is illustrated in FIG. 16C. As shown, one bypass diode is electrically connected between each pair of neighboring super cells approximately midway along the super cells. Bypass diode 4901A is electrically connected between neighboring solar cells on the first and second super cells, bypass diode 4901B is electrically connected between neighboring solar cells on the second and third super cells, bypass diode 4901C is electrically connected between neighboring solar cells on the third and fourth super cells, and so forth. A second set of bypass diodes may be included to reduce the number solar cells that will be bypassed in the event of partial shade. For example, a bypass diode 4901A is electrically connected between the first and second super cells at an intermediate point between bypass diodes 4901A and 4901B, a bypass diode 4902B is electrically connected between the second and third super cells at an intermediate point between bypass diodes 4901B and 4901C, and so forth, reducing the number of cells per bypass diode. Optionally, yet another set of bypass diodes may be electrically connected to further reduce the number of solar cells to be bypassed in the event of partial shade. Bypass diode 4901A is electrically connected between the first and second super cells at an intermediate point between bypass diodes 4901A and 4901B, bypass diode 4903B is electrically connected between second and third super cells at an intermediate point between bypass diodes 4902B and 4901C, further reducing the number of cells per bypass diode. This configuration results in a nested configuration of bypass diodes, which allows small groups of cells to be bypassed during partial shading. Additional diodes may be electrically connected in this manner until a desired number of solar cells per bypass diode is achieved, e.g., about 8, about 6, about 4, or about 2 per bypass diode. In some modules, about 4 solar cells per bypass diode is desired. If desired, one or more of the bypass diodes illustrated in FIG. 16C may be incorporated into hidden flexible interconnect as illustrated in FIG. 16B.

The following enumerated paragraphs provide additional non-limiting aspects of the disclosure.

1. A solar module comprising:

a number N greater than or equal to about 250 rectangular or substantially rectangular silicon solar cells arranged as a plurality of series-connected super cells in two or more parallel rows, each super cell comprising a plurality of the silicon solar cells arranged in line with long sides of adjacent silicon solar cells overlapping and conductively bonded directly to each other with an electrically and thermally conductive adhesive to electrically connect the silicon solar cells in the super cell in series; and

one or more bypass diodes;

wherein each pair of adjacent parallel rows in the solar module is electrically connected by a bypass diode that is conductively bonded to a rear surface electrical contact on a centrally located solar cell in one row of the pair and conductively bonded to a rear surface electrical contact on an adjacent solar cell in the other row of the pair.

2. The solar module of clause 1, wherein each pair of adjacent parallel rows is electrically connected by at least one other bypass diode that is conductively bonded to a rear surface electrical contact on a solar cell in one row of the pair and conductively bonded to a rear surface electrical contact on an adjacent solar cell in the other row of the pair.

3. The solar module of clause 2, wherein each pair of adjacent parallel rows is electrically connected by at least one other bypass diode that is conductively bonded to a rear surface electrical contact on a solar cell in one row of the pair and conductively bonded to a rear surface electrical contact on an adjacent solar cell in the other row of the pair.

4. The solar module of clause 1, wherein the electrically and thermally conductive adhesive forms bonds between adjacent solar cells having a thickness perpendicular to the solar cells of less than or equal to about 50 micron and a thermal conductivity perpendicular to the solar cells greater than or equal to about 1.5 W/(meter-K).

5. The solar module of clause 1, wherein the super cells are encapsulated in a thermoplastic olefin layer between front and back glass sheets.

6. The solar module of clause 1, wherein the conductive bonds between overlapping solar cells provide mechanical compliance to the super cells accommodating a mismatch in thermal expansion between the super cells and the glass front sheet in a direction parallel to the rows for a temperature range of about −40° C. to about 100° C. without damaging the solar module.

7. The solar module of any of clauses 1-6, wherein N is greater than or equal to about 300, greater than or equal to about 350, greater than or equal to about 400, greater than or equal to about 450, greater than or equal to about 500, greater than or equal to about 550, greater than or equal to about 600 greater than or equal to about 650, or greater than or equal to about 700.

8. The solar module of any of clauses 1-7, wherein the super cells are electrically connected to provide a high direct current voltage of greater than or equal to about 120 volts, greater than or equal to about 180 volts, greater than or equal to about 240 volts, greater than or equal to about 300 volts, greater than or equal to about 360 volts, greater than or equal to about 420 volts, greater than or equal to about 480 volts, greater than or equal to about 540 volts, or greater than or equal to about 600 volts.

9. A solar energy system comprising:

the solar module of clause 1; and

an inverter electrically connected to the solar module and configured to convert a DC output from the solar module to provide an AC output.

10. The solar energy system of clause 9, wherein the inverter lacks a DC to DC boost component.

11. The solar energy system of clause 9, wherein the inverter is configured to operate the solar module at a direct current voltage above a minimum value set to avoid reverse biasing a solar cell.

12. The solar energy system of clause 11, wherein the minimum voltage value is temperature dependent.

13. The solar energy system of clause 9, wherein the inverter is configured to recognize a reverse bias condition and operate the solar module at a voltage that avoids the reverse bias condition.

14. The solar energy system of clause 13, wherein the inverter is configured to operate the solar module in a local maximum region of the solar module's voltage-current power curve to avoid the reverse bias condition.

15. The solar energy system of any of clauses 9-14, wherein the inverter is a microinverter integrated with the solar module.

16. A solar module comprising:

a number N greater than or equal to about 150 rectangular or substantially rectangular silicon solar cells arranged as a plurality of super cells in two or more parallel rows, each super cell comprising a plurality of the silicon solar cells arranged in line with long sides of adjacent silicon solar cells overlapping and conductively bonded to each other to electrically connect the silicon solar cells in series;

wherein the super cells are electrically connected to provide a high direct current voltage of greater than or equal to about 90 volts.

17. The solar module of clause 16, comprising one or more flexible electrical interconnects arranged to electrically connect the plurality of super cells in series to provide the high direct current voltage.

18. The solar module of clause 17, comprising module level power electronics including an inverter that converts the high direct current voltage to an alternating current voltage.

19. The solar module of clause 18, wherein the module level power electronics sense the high direct current voltage and operate the module at an optimum current-voltage power point.

20. The solar module of clause 16, comprising module level power electronics electrically connected to individual pairs of adjacent series connected rows of super cells, electrically connecting one or more of the pairs of rows of super cells in series to provide the high direct current voltage, and comprising an inverter that converts the high direct current voltage to an alternating current voltage.

21. The solar module of clause 20, wherein the module level power electronics sense the voltage across each individual pair of rows of super cells and operate each individual pair of rows of super cells at an optimum current-voltage power point.

22. The solar module of clause 21, wherein the module level power electronics switch an individual pair of rows of super cells out of a circuit providing the high direct current voltage if the voltage across the pair of rows is below a threshold value.

23. The solar module of clause 16, comprising module level power electronics electrically connected to each individual row of super cells, electrically connecting two or more of the rows of super cells in series to provide the high direct current voltage, and comprising an inverter that converts the high direct current voltage to an alternating current voltage.

24. The solar module of clause 23, wherein the module level power electronics sense the voltage across each individual row of super cells and operate each individual row of super cells at an optimum current-voltage power point.

25. The solar module of clause 24, wherein the module level power electronics switch an individual row of super cells out of a circuit providing the high direct current voltage if the voltage across the row of super cells is below a threshold value.

26. The solar module of clause 16, comprising module level power electronics electrically connected to each individual super cell, electrically connecting two or more of the super cells in series to provide the high direct current voltage, and comprising an inverter that converts the high direct current voltage to an alternating current voltage.

27. The solar module of clause 26, wherein the module level power electronics sense the voltage across each individual super cell and operate each individual super cell at an optimum current-voltage power point.

28. The solar module of clause 27, wherein the module level power electronics switch an individual super cell out of a circuit providing the high direct current voltage if the voltage across the super cell is below a threshold value.

29. The solar module of clause 16, wherein each super cell is electrically segmented into a plurality of segments by hidden taps, the solar module comprising module level power electronics electrically connected to each segment of each super cell through the hidden taps, electrically connecting two or segments in series to provide the high direct current voltage, and comprising an inverter that converts the high direct current voltage to an alternating current voltage.

30. The solar module of clause 29, wherein the module level power electronics sense the voltage across each individual segment of each super cell and operate each individual segment at an optimum current-voltage power point.

31. The solar module of clause 30, wherein the module level power electronics switch an individual segment out of a circuit providing the high direct current voltage if the voltage across the segment is below a threshold value.

32. The solar module of any of clauses 19, 21, 24, 27, or 30, wherein the optimum current-voltage power point is a maximum current-voltage power point.

33. The solar module of any of clauses 18-22, wherein the module level power electronics lack a direct current to direct current boost component.

34. The solar module of any of clauses 16-33, wherein N is greater than or equal to about 200, greater than or equal to about 250, greater than or equal to about 300, greater than or equal to about 350, greater than or equal to about 400, greater than or equal to about 450, greater than or equal to about 500, greater than or equal to about 550, greater than or equal to about 600 greater than or equal to about 650, or greater than or equal to about 700.

35. The solar module of any of clauses 16-34, wherein the high direct current voltage is greater than or equal to about 120 volts, greater than or equal to about 180 volts, greater than or equal to about 240 volts, greater than or equal to about 300 volts, greater than or equal to about 360 volts, greater than or equal to about 420 volts, greater than or equal to about 480 volts, greater than or equal to about 540 volts, or greater than or equal to about 600 volts.

36. A solar photovoltaic system comprising:

two or more solar modules electrically connected in parallel; and

an inverter;

wherein each solar module comprises a number N greater than or equal to about 150 rectangular or substantially rectangular silicon solar cells arranged as a plurality of super cells in two or more parallel rows, each super cell in each module comprises two or more of the silicon solar cells in that module arranged in line with long sides of adjacent silicon solar cells overlapping and conductively bonded to each other to electrically connect the silicon solar cells in series, and in each module the super cells are electrically connected to provide a high voltage direct current module output of greater than or equal to about 90 volts; and

wherein the inverter is electrically connected to the two or more solar modules to convert their high voltage direct current output to an alternating current.

37. The solar photovoltaic system of clause 36, wherein each solar module comprises one or more flexible electrical interconnects arranged to electrically connect the super cells in the solar module in series to provide the solar module's high voltage direct current output.

38. The solar photovoltaic system of clause 36, comprising at least a third solar module electrically connected in series with a first one of the two or more solar modules electrically connected in parallel, wherein the third solar module comprises a number N′ greater than or equal to about 150 rectangular or substantially rectangular silicon solar cells arranged as a plurality of super cells in two or more parallel rows, each super cell in the third solar module comprises two or more of the silicon solar cells in that module arranged in line with long sides of adjacent silicon solar cells overlapping and conductively bonded to each other to electrically connect the silicon solar cells in series, and in the third solar module the super cells are electrically connected to provide a high voltage direct current module output of greater than or equal to about 90 volts.

39. The solar photovoltaic system of clause 38, comprising at least a fourth solar module electrically connected in series with a second one of the two or more solar modules electrically connected in parallel, wherein the fourth solar module comprises a number N″ greater than or equal to about 150 rectangular or substantially rectangular silicon solar cells arranged as a plurality of super cells in two or more parallel rows, each super cell in the fourth solar module comprises two or more of the silicon solar cells in that module arranged in line with long sides of adjacent silicon solar cells overlapping and conductively bonded to each other to electrically connect the silicon solar cells in series, and in the fourth solar module the super cells are electrically connected to provide a high voltage direct current module output of greater than or equal to about 90 volts.

40. The solar photovoltaic system of clauses 36-39, comprising fuses arranged to prevent a short circuit occurring in any one of the solar modules from dissipating power generated in the other solar modules.

41. The solar photovoltaic system of any of clauses 36-40, comprising blocking diodes arranged to prevent a short circuit occurring in any one of the solar modules from dissipating power generated in other ones of the solar modules.

42. The solar photovoltaic system of any of clauses 36-41, comprising positive and negative buses to which the two or more solar modules are electrically connected in parallel and to which the inverter is electrically connected.

43. The solar photovoltaic system of any of clauses 36-42, comprising a combiner box to which the two or more solar modules are electrically connected by a separate conductor, the combiner box electrically connecting the solar modules in parallel.

44. The solar photovoltaic system of clause 43, wherein the combiner box comprises fuses arranged to prevent a short circuit occurring in any one of the solar modules from dissipating power generated in the other solar modules.

45. The solar photovoltaic system of clause 43 or clause 44, wherein the combiner box comprises blocking diodes arranged to prevent a short circuit occurring in any one of the solar modules from dissipating power generated in other ones of the solar modules.

46. The solar photovoltaic system of any of clauses 36-45, wherein the inverter is configured to operate the solar modules at a direct current voltage above a minimum value set to avoid reverse biasing a module.

47. The solar photovoltaic system of any of clauses 36-45, wherein the inverter is configured to recognize a reverse bias condition and operate the solar modules at a voltage that avoids the reverse bias condition.

48. The solar module of any of clauses 36-47, wherein N is greater than or equal to about 200, greater than or equal to about 250, greater than or equal to about 300, greater than or equal to about 350, greater than or equal to about 400, greater than or equal to about 450, greater than or equal to about 500, greater than or equal to about 550, greater than or equal to about 600 greater than or equal to about 650, or greater than or equal to about 700.

49. The solar module of any of clauses 36-48, wherein the high direct current voltage is greater than or equal to about 120 volts, greater than or equal to about 180 volts, greater than or equal to about 240 volts, greater than or equal to about 300 volts, greater than or equal to about 360 volts, greater than or equal to about 420 volts, greater than or equal to about 480 volts, greater than or equal to about 540 volts, or greater than or equal to about 600 volts.

50. The solar photovoltaic system of any of clauses 36-49, positioned on a roof top.

51. A solar photovoltaic system comprising:

a first solar module comprising a number N greater than or equal to about 150 rectangular or substantially rectangular silicon solar cells arranged as a plurality of super cells in two or more parallel rows, each super cell comprising a plurality of the silicon solar cells arranged in line with long sides of adjacent silicon solar cells overlapping and conductively bonded to each other to electrically connect the silicon solar cells in series; and

an inverter;

wherein the super cells are electrically connected to provide a high direct current voltage of greater than or equal to about 90 volts to the inverter, which converts the direct current to an alternating current.

52. The solar photovoltaic system of clause 51, wherein the inverter is a microinverter integrated with the first solar module.

53. The solar photovoltaic system of clause 51, wherein the first solar module comprises one or more flexible electrical interconnects arranged to electrically connect the super cells in the solar module in series to provide the solar module's high voltage direct current output.

54. The solar photovoltaic system of any of clauses 51-53, comprising at least a second solar module electrically connected in series with the first solar module, wherein the second solar module comprises a number N′ greater than or equal to about 150 rectangular or substantially rectangular silicon solar cells arranged as a plurality of super cells in two or more parallel rows, each super cell in the second solar module comprises two or more of the silicon solar cells in that module arranged in line with long sides of adjacent silicon solar cells overlapping and conductively bonded to each other to electrically connect the silicon solar cells in series, and in the second solar module the super cells are electrically connected to provide a high voltage direct current module output of greater than or equal to about 90 volts.

55. The solar module of any of clauses 51-54, wherein the inverter lacks a direct current to direct current boost component.

56. The solar module of any of clauses 51-55, wherein N is greater than or equal to about 200, greater than or equal to about 250, greater than or equal to about 300, greater than or equal to about 350, greater than or equal to about 400, greater than or equal to about 450, greater than or equal to about 500, greater than or equal to about 550, greater than or equal to about 600 greater than or equal to about 650, or greater than or equal to about 700.

57. The solar module of any of clauses 51-56, wherein the high direct current voltage is greater than or equal to about 120 volts, greater than or equal to about 180 volts, greater than or equal to about 240 volts, greater than or equal to about 300 volts, greater than or equal to about 360 volts, greater than or equal to about 420 volts, greater than or equal to about 480 volts, greater than or equal to about 540 volts, or greater than or equal to about 600 volts.

58. A solar module comprising:

less than one bypass diode per 25 solar cells;

wherein the electrically and thermally conductive adhesive forms bonds between adjacent solar cells having a thickness perpendicular to the solar cells of less than or equal to about 50 micron and a thermal conductivity perpendicular to the solar cells greater than or equal to about 1.5 W/(meter-K).

59. The solar module of clause 58, wherein the super cells are encapsulated in a thermoplastic olefin layer between front and back sheets.

60. The solar module of clause 58, wherein the super cells are encapsulated in between glass front and back sheets.

61. The solar module of clause 58, comprising less than one bypass diode per 30 solar cells, or less than one bypass diode per 50 solar cells, or less than one bypass diode per 100 solar cells, or only a single bypass diode, or not comprising a bypass diode.

62. The solar module of clause 58, comprising no bypass diodes, or only a single bypass diode, or not more than three bypass diodes, or not more than six bypass diodes, or not more than ten bypass diodes.

63. The solar module of clause 58, wherein the conductive bonds between overlapping solar cells provide mechanical compliance to the super cells accommodating a mismatch in thermal expansion between the super cells and the glass front sheet in a direction parallel to the rows for a temperature range of about −40° C. to about 100° C. without damaging the solar module.

64. The solar module of any of clauses 58-63, wherein N is greater than or equal to about 300, greater than or equal to about 350, greater than or equal to about 400, greater than or equal to about 450, greater than or equal to about 500, greater than or equal to about 550, greater than or equal to about 600 greater than or equal to about 650, or greater than or equal to about 700.

65. The solar module of any of clauses 58-64, wherein the super cells are electrically connected to provide a high direct current voltage of greater than or equal to about 120 volts, greater than or equal to about 180 volts, greater than or equal to about 240 volts, greater than or equal to about 300 volts, greater than or equal to about 360 volts, greater than or equal to about 420 volts, greater than or equal to about 480 volts, greater than or equal to about 540 volts, or greater than or equal to about 600 volts.

66. A solar energy system comprising:

the solar module of clause 58; and

an inverter electrically connected to the solar module and configured to convert a DC output from the solar module to provide an AC output.

67. The solar energy system of clause 66, wherein the inverter lacks a DC to DC boost component.

68. The solar energy system of clause 66, wherein the inverter is configured to operate the solar module at a direct current voltage above a minimum value set to avoid reverse biasing a solar cell.

69. The solar energy system of clause 68, wherein the minimum voltage value is temperature dependent.

70. The solar energy system of clause 66, wherein the inverter is configured to recognize a reverse bias condition and operate the solar module at a voltage that avoids the reverse bias condition.

71. The solar energy system of clause 70, wherein the inverter is configured to operate the solar module in a local maximum region of the solar module's voltage-current power curve to avoid the reverse bias condition.

72. The solar energy system of any of clauses 66-71, wherein the inverter is a microinverter integrated with the solar module.

73. The solar energy system of any of clauses 1-72, arranged in an overlapping shingled manner with another solar module to which it is electrically connected in an overlapping region.

This disclosure is illustrative and not limiting. Further modifications will be apparent to one skilled in the art in light of this disclosure and are intended to fall within the scope of the appended claims.

Number	Date	Country
62064834	Oct 2014	US
62064260	Oct 2014	US
62048858	Sep 2014	US
62042615	Aug 2014	US
62036215	Aug 2014	US
62003223	May 2014	US
62081200	Nov 2014	US
62113250	Feb 2015	US
62082904	Nov 2014	US
62103816	Jan 2015	US
62111757	Feb 2015	US

	Number	Date	Country
Parent	14530405	Oct 2014	US
Child	14722069		US
Parent	14674983	Mar 2015	US
Child	14530405		US

HIGH VOLTAGE SOLAR PANEL

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CROSS REFERENCE TO RELATED APPLICATIONS

Provisional Applications (11)

Continuation in Parts (2)