Patent Application
20100275976
This invention relates to photovoltaic (PV) modules and more particularly to configuring PV cells within a PV module to permit conductors associated with a string or strings of PV cells to extend from a perimeter edge of the PV module in which they are installed.
The design and production of PV modules comprised of crystalline silicon PV cells has remained virtually unchanged for more than thirty years. A typical PV cell comprises semiconductor material with at least one p-n junction and front and back side surfaces having current collecting electrodes. When a conventional crystalline PV cell is illuminated, it generates an electric current of about 34 mA/cm2 at about 0.6-0.62V. A plurality of PV cells are typically electrically interconnected in series and/or in parallel strings to form a PV module that produces higher voltages and/or currents than a single PV cell.
PV cells may be interconnected in strings by means of metallic tabs, made for example from tinned copper. A typical PV module may comprise 36-100 PV series interconnected cells, for example, and these may be combined into typically 2 to 4 PV strings to achieve higher voltages than would be obtainable with a single PV cell.
In PV modules comprising series-interconnected PV cells, the module only performs optimally when all the series interconnected PV cells are illuminated with approximately similar light intensity. However, if even one PV cell within the series of PV cells is shaded, while all other cells are illuminated, the entire PV module is adversely affected resulting in a substantial decrease in power output from the PV module. It was demonstrated (“Numerical Simulation of Photovoltaic Generators with Shaded Cells”, V. Quaschning and R. Hanitsch, 30th Universities Power Engineering Conference, Greenwich, Sep. 5-7, 1995, p.p. 583-586) that a Photovoltaic module comprising 36 PV cells loses up to 70% of the generated power when only 75% of one PV cell is shaded. In addition to temporary power loss, the module may be permanently damaged as a result of cell shading because when a PV cell is shaded, the cell acts as a large resistor rather than a power generator. In this situation, the other cells in the module drive current through this large resistor which results in heating of the shaded cell which may increase the cell temperature to 160° C. or higher and this can damage the shaded PV cell and the entire PV module if a temperature of this magnitude persists. In order to reduce the risk of PV module damage due to excessive heating in the event of shading, practically all PV modules employ by-pass diodes (BPD) connected across an entire panel or across strings in a panel. Bypass diodes effectively “short out” a single string or an entire module containing shaded cells. Although this approach causes the power generated in the shorted string to be completely lost, it allows the rest of the system to continue producing power and also reduces the heating of the shaded cell.
Since PV modules are generally expected to operate outdoors for typically 25 years without degradation, their construction must withstand various weather and environmental conditions. Typical PV module construction involves the use of a transparent sheet of low iron tempered glass covered with a sheet of polymeric encapsulant material such as ethylene vinyl acetate or thermoplastic material such as urethane on a front side of the module, for example. An array of PV cells is placed onto the polymeric encapsulant material in such a way that the front sides of the cells face the transparent glass sheet. A back side of the array is covered with an additional layer of encapsulant material and a back sheet layer of weather protecting material, such as Tedlar® by DuPont, or a glass sheet. The additional layer of encapsulant material and the back sheet layer typically have openings to provide for electrical conductors connected to PV strings in the module to be passed through the back encupsulant layer and back sheet of weather protecting material to provide for connection to an electrical circuit. For a PV module having an array of two strings of PV cells, typically four conductors are arranged to pass through the openings so that they are all in proximity with each other so they can be terminated in a junction box mounted on the back sheet layer. The glass, encapsulant layers, cells and back sheet layer are typically vacuum laminated to eliminate air bubbles and to protect the PV cells from moisture penetration from the front and back sides and also from the edges. The electrical interconnections of PV strings and connections to bypass diodes are made in the junction box. The junction box is sealed on the back side of the PV module.
In some existing PV modules, an aluminum frame extends around the perimeter of the PV module and protects against damage, provides mechanical strength against wind and snow loads and facilitates mounting of the module to a support. A plurality of supports may be provided to support a plurality of PV modules and such PV modules are typically connected together by cables connected between junction boxes of adjacent modules. Installation of PV modules in this manner can be quite expensive.
The fabrication of the PV modules described above is quite complicated and expensive. Lay up of the PV module before lamination requires a separate step of “bussing” in which the cells are connected in strings by soldering thin busses between them. This increases production costs and limits production capacity.
In addition, locating a junction box on an outer surface of the back sheet of a PV module requires the formation of the above described openings through the back side encapsulant sheet and back side protection sheet which also increases the cost of production and can render the module susceptible to moisture penetration. In addition, the cost of the junction box is significant to the overall cost of PV module. Furthermore, since the junction box typically has a small volume and is made of hermetically sealed plastic, the bypass diodes can become very hot, when a string or module is shaded, which can result in substantial heating inside the junction box and this heat can be transferred to the adjacent PV cells. Therefore there is a risk that the temperature inside the junction box may exceed a safe level resulting in damage to one or more cells in the PV module.
U.S. Pat. No. 6,870,087 B1, 2005, entitled: Assembly Method and Apparatus for Photovoltaic Module, to Patrick Gallagher describes a PV module that comprises only one string of PV cells. Outlet cables are connected to terminal PV cells. These cables are used for electrical connection of one PV module to another in the field. The PV cells string is mounted in a box-like structure comprised of an upper pan and lower pan. The lower pan defines a conduit for the flow of air beneath the PV string. A set of such PV modules is mounted in a sun tracking assembly.
US Patent Publication 2007/0102038 A1, published May 10, 2007 to Kirschning relates to a holding element for photovoltaic modules for fastening a photovoltaic module to a holding device and to a process for the electrical connection of the PV module to the holding element. A conventional junction box is equipped with at least one connecting element provided for inserting onto/into a receiving area of the holding element. This allows direct electric power transfer from the junction box to the holding element, eliminating conventional cables that are normally freely suspended on the back side of PV modules and exposed to wind and weather. The holding element also facilitates the interconnecting neighboring PV modules using receiving elements on the edges of neighboring PV modules thus enabling easy plug- and play interconnection of adjacent PV modules.
The present invention may provide for more optimal and less costly PV module fabrication, by eliminating bus bar soldering for interconnection of PV strings within the PV module active area, thereby simplifying and increasing production capacity of PV module lay-up before lamination. The present invention may also eliminate the need for a conventional junction box on the rear surface of the module, thereby decreasing the complexity and cost of PV module production.
The present invention may also simplify PV module interconnection thereby decreasing the cost of PV module installation.
In accordance with one aspect of the invention, there is provided a PV module. The apparatus includes a plurality of PV cells arranged in a planar array having a front side and a back side, the plurality of PV cells being electrically connected together in at least one string having a positive terminal and a negative terminal for supplying electrical energy to a load. The apparatus also includes positive and negative conductors connected to the positive and negative terminals respectively. The apparatus further includes front and back encapsulating sheets disposed on the front and back sides of the array to form a sub-laminate comprised of the array and the front and back encapsulating sheets, the sub-laminate having a first outer perimeter edge. Each of the positive and negative conductors has a respective portion extending from the positive and negative terminals respectively, between the front and back encapsulating sheets and has first and second terminating portions respectively extending outwardly from the first outer perimeter edge of the sub-laminate. The apparatus further includes front and back protectors disposed on the front and back encapsulating sheets respectively to form a laminate comprising the sub-laminate and the front and back protectors. The front and back protectors have second and third outer perimeter edges respectively generally coterminous with the first outer perimeter edge and defining an outer perimeter edge of the laminate. The first and second terminating portions extend outwardly from the outer perimeter edge of the laminate.
The first and second terminating portions may extend from opposite edge portions of the outer perimeter edge of the laminate.
The first and second terminating portions may extend from a common edge portion of the outer perimeter edge of the laminate.
The array may be electrically connected into a plurality of subset strings, each subset string having a positive terminal and a negative terminal and may include conductors disposed entirely between the first and second encapsulating sheets, operably configured to electrically connect the subset strings together, the positive and negative conductors being electrically connected to first and last subset strings of the subset strings that are electrically connected together.
The array may be electrically connected into a plurality of subset strings, each subset string having a positive terminal and a negative terminal and may include conductors disposed outside the outer perimeter edge of the laminate operably configured to electrically connect the subset strings together, the positive and negative conductors being electrically connected to first and last subset strings of the subset strings that are electrically connected together.
The apparatus may further include a frame surrounding the outer perimeter edge of the laminate, the frame having a holder operably configured to hold electrical connectors, the first and second terminating portions of the positive and negative conductors extending into the holder.
The apparatus may further include first and second electrical connectors disposed in the holder, the first and second terminating portions being connected to the first and second electrical connectors respectively.
The apparatus may further include third and fourth electrical connectors in the holder such that the third and fourth electrical connectors are accessible externally of the holder, the third and fourth electrical connectors being electrically connected to the first and second connectors respectively, to enable the array to be connected to a load.
The frame may include a plurality of frame members connected together, wherein each frame member holds a respective portion of the outer perimeter edge of the laminate.
The frame members may have end portions having integral openings therein and may include corner connectors operably configured to be received in the integral openings to connect adjacent frame members together.
At least one of the frame members may have a holder for holding a plurality of electrical connectors.
The array may be electrically connected into a plurality of subset strings, each subset string having a positive terminal and a negative terminal and respective conductors extending from the positive and negative terminals the respective conductors each having a terminating portion extending outwardly of the outer perimeter of the laminate and extending into the holder.
The apparatus may further include a plurality of electrical connectors in the holder, the terminating portions of the conductors being connected to respective electrical connectors in the holder.
The apparatus may further include a bypass diode in the holder and electrically connected to a pair of electrical connectors associated with a subset string of PV cells, to protect the subset string of PV cells from excessive electrical current when the subset string is not producing electric current.
The apparatus may further include a protector operably configured to protect the electrical connectors from weather.
The apparatus may further include a frame member having a receptacle and a first opening adjacent the receptacle and in communication with the receptacle, at least a portion of the outer perimeter edge of the laminate being in the receptacle and whereby at least one of the first and second terminating portions extends across a portion of the outer perimeter edge of the laminate and across a portion of a back side of the laminate in the receptacle and extends through the first opening to facilitate connection of the at least one of the first and second terminating portions to an electrical connector adjacent the back side of the laminate and adjacent the outer perimeter edge of the laminate.
The frame member may have a mounting portion, adjacent the receptacle, for mounting an electrical connector holder to the frame member, the mounting portion being disposed generally parallel to the laminate such that when the electrical connector holder is mounted to the mounting portion, the electrical connector holder extends generally outwardly away from the back side of the laminate.
The first opening may be in the mounting portion.
The apparatus may further include an electrical connector holder on the mounting portion, for holding at least one electrical connector, the electrical connector holder being positioned on the mounting portion such that the at least one of the first and second terminating portions can extend through the first opening into the electrical connector holder and into the electrical connector held therein.
The electrical connector holder may be integral with the electrical connector mount.
The mounting portion may have a plurality of openings for receiving corresponding terminating portions.
The apparatus may further include an electrical connector holder including a plurality of walls defining a plurality of compartments, the plurality of walls including a bottom wall, the bottom wall having pairs of openings in each compartment, each pair of openings being disposed about a respective pair of openings of the plurality of openings in the mounting portion, and each compartment comprising a pair of electrical connectors, whereby positive and negative terminating portions of respective strings of PV cells in the laminate extend through respective openings in the mounting portion and through the pair of openings associated with a respective compartment and wherein the first and second terminating portions may be connected to the respective pair of electrical connectors in the compartment associated with the openings through which the first and second terminating portions extend.
The apparatus may further include bypass diodes connected between respective connectors of the pairs of the electrical connectors associated with respective compartments.
At least some of the walls may have passageways between adjacent compartments.
The passageways may have wires extending therethrough for connecting the electrical connectors of adjacent compartments.
The wires may connect the electrical connectors of adjacent compartments such that the strings of PV cells are electrically connected in a series string having positive and negative terminals and the apparatus may further include first and second pairs of externally accessible electrical connectors, each pair being on an opposite side of the electrical connector holder and adjacent a respective side of the laminate, one connector of each pair being electrically connected together, and one connector of each pair being connected to a respective one of the positive and negative terminals of the series string of PV cells.
The first and second pairs of externally accessible connectors may have coplanar connection axes that extend generally in a plane parallel to a plane of the laminate.
The mounting portion may have a plurality of openings therein for receiving respective terminating portions of respective strings of PV cells within the laminate therethrough.
The apparatus may further include a plurality of electrical connector holders on the mounting portion, each electrical connector holder having a respective pair of electrical connectors and each electrical connector holder being located over a respective pair of openings in the mounting portion to enable the respective terminating portions of respective strings of PV cells to extend through respective openings of the pairs of openings, into respective electrical connector holders for connection to the electrical connectors therein.
The electrical connector holders may have end walls with end openings therein and conduits may extend between end openings of adjacent electrical connector holders.
The apparatus may further include wires extending through the conduits to electrically connect the electrical connectors in adjacent electrical connector holders.
The wires may connect the electrical connectors of adjacent electrical connector holders such that the strings of PV cells are electrically connected in a series string having positive and negative terminals and the apparatus may further include first and second pairs of externally accessible electrical connectors, each pair being on respective electrical connector holders on opposite sides of the laminate, one connector of each pair being electrically connected together, and one connector of each pair being connected to a respective one of the positive and negative terminals of the series string of PV cells.
The first and second pairs of externally accessible connectors may have coplanar connection axes that extend generally in a plane parallel to a plane of the laminate.
In accordance with another aspect of the invention, there is provided a frame apparatus for a PV module. The apparatus includes an elongate body having first and second opposite ends and a module holder between the first and second opposite ends, the module holder being operably configured to hold an edge portion of an outer perimeter edge of the PV module. The apparatus also includes first and second frame connectors disposed at the first and second ends respectively, the first and second frame connectors being operably configured to receive and hold a frame connector element operably configured to connect two adjacent frame members together. The apparatus further includes an electrical connector holder adjacent the module holder, operably configured to hold at least one electrical connector. The apparatus also includes an opening extending between the module holder and the electrical connector holder, the opening being operably configured to receive therethrough at least one conductor extending from the outer perimeter edge of the PV module such that at least one conductor can extend from the outer perimeter edge of the PV module into the module holder and from the module holder into an electrical connector in the electrical connector holder, in a continuous curve.
The elongate body may include first and second parallel spaced apart walls forming the module holder and third and fourth parallel spaced apart walls forming the electrical connector holder, the first and second parallel spaced apart walls extending in a direction opposite to the third and fourth parallel spaced apart walls.
The body may comprise an inner wall between the first and second parallel spaced apart walls and the third and fourth spaced apart walls, the first and second parallel spaced apart walls and the third wall defining an edge space in which a portion of the outer perimeter edge portion of the PV module can be received and the third and fourth parallel spaced apart walls and the inner wall defining an electrical connector space in which at least one electrical connector may be mounted, the opening being disposed in the inner wall.
The apparatus may further include first and second transverse walls extending between the third and fourth walls, the third and fourth parallel spaced apart walls further defining the electrical connector space.
The apparatus may further include first and second connector mounts on the first and second transverse walls respectively operably configured to mount first and second electrical connectors to the first and second transverse walls respectively.
The apparatus may further include a removable cover operably configured to cooperate with the third and fourth walls and the first and second transverse walls to enclose the electrical connector space.
In accordance with another aspect of the invention, there is provided a frame apparatus for a PV module including a laminate having an outer perimeter edge and at least first and second terminating conductors extending from the outer perimeter edge. The apparatus includes a frame member having a receptacle and a first opening adjacent the receptacle and in communication with the receptacle. At least a portion of the outer perimeter edge of the laminate is in the receptacle and at least one of the first and second terminating conductors extends across a portion of the outer perimeter edge of the laminate and across a portion of a back side of the laminate, in the receptacle. The apparatus further includes at least one of the first and second terminating portions extending through the first opening to facilitate connection of at least one of the first and second terminating conductors to an electrical connector adjacent the back side of the laminate and adjacent the outer perimeter edge of the laminate.
The frame member may have a mounting portion, adjacent the receptacle, for mounting an electrical connector holder to the frame member, the mounting portion being disposed generally parallel to the laminate such that when the electrical connector holder is mounted to the mounting portion, the electrical connector holder extends generally outwardly away from the back side of the laminate.
The first opening may be in the mounting portion.
The apparatus may further include an electrical connector holder on the mounting portion, for holding at least one electrical connector, the electrical connector holder being positioned on the mounting portion such that at least one of the first and second terminating conductors can extend through the first opening into the electrical connector holder and into the electrical connector held therein.
The electrical connector holder may be integral with the electrical connector mount.
The mounting portion may have a plurality of openings for receiving respective terminating conductors.
The apparatus may further include an electrical connector holder including a plurality of walls defining a plurality of compartments, the plurality of walls including a bottom wall, the bottom wall having pairs of openings in each compartment, each pair of openings being disposed about a respective pair of openings of the plurality of openings in the mounting portion, and each compartment comprising a pair of electrical connectors, whereby positive and negative terminating conductor of respective strings of PV cells in the laminate extend through respective openings in the mounting portion and into a respective compartment and wherein the first and second terminating conductors are connected to the respective pair of electrical connectors in the compartment associated with the openings through which the first and second terminating portions extend.
The apparatus may further include bypass diodes connected between respective connectors of the pairs of the electrical connectors associated with respective the compartments.
At least some of the walls may have passageways between adjacent compartments.
The passageways may have wires extending therethrough for connecting the electrical connectors of adjacent compartments.
The wires may connect the electrical connectors of adjacent compartments such that the strings of PV cells are electrically connected in a series string having positive and negative terminals and the apparatus may further include first and second pairs of externally accessible electrical connectors, each pair being on an opposite side of the electrical connector holder and adjacent a respective edge of the laminate, one connector of each pair being electrically connected together, and one connector of each pair being connected to a respective one of the positive and negative terminating conductors of the series string of PV cells.
The first and second pairs of externally accessible connectors may have coplanar connection axes that extend generally in a plane parallel to a plane of the laminate.
The mounting portion may have a plurality of openings therein for receiving respective terminating portions of respective strings of PV cells within the laminate therethrough.
The apparatus may further include a plurality of electrical connector holders on the mounting portion, each electrical connector holder having a respective pair of electrical connectors and each electrical connector holder being located over a respective pair of openings in the mounting portion to enable the respective terminating conductors portions of respective strings of PV cells to extend through respective openings of the pairs of openings, into respective electrical connector holders for connection to the electrical connectors therein.
The electrical connector holders may have end walls with end openings therein and conduits may extend between end openings of adjacent electrical connector holders.
The apparatus may further include wires extending through the conduits to electrically connect the electrical connectors in adjacent electrical connector holders.
The wires may connect the electrical connectors of adjacent electrical connector holders such that the strings of PV cells are electrically connected in a series string having positive and negative terminating conductors and the apparatus may further include first and second pairs of externally accessible electrical connectors, each pair being on respective electrical connector holders on opposite edges of the laminate, one connector of each pair being electrically connected together, and one connector of each pair being connected to a respective one of the positive and negative terminating conductors of the series string of PV cells.
The first and second pairs of externally accessible connectors may have coplanar connection axes that extend generally in a plane parallel to a plane of the laminate.
In accordance with another aspect of the invention, there is provided a frame system for a PV module. The system includes a plurality of frame members, operably configured to surround and hold an outer perimeter edge of the PV module. Each frame member includes an elongate body having first and second opposite ends and a module holder between the first and second opposite ends, the module holder being operably configured to hold a respective edge portion of the outer perimeter edge of the PV module. Each frame member also includes first and second frame connectors disposed at the first and second ends respectively, the first and second frame connectors being operably configured to receive and hold a frame connector element operably configured to connect two adjacent frame members together. At least one of the plurality of frame members includes an electrical connector holder adjacent the module holder, operably configured to hold at least one electrical connector, and an opening extending between the module holder and the electrical connector holder, the opening being operably configured to receive therethrough at least one conductor extending from the outer perimeter edge of the PV module such that at least one conductor can extend from the outer perimeter edge of the PV module into the module holder and from the module holder into an electrical connector in the electrical connector holder, in a continuous curve.
In accordance with another aspect of the invention, there is provided a method for making a PV module. The method involves arranging a plurality of PV cells in a planar array, the planar array having a front side and a back side. The method also involves electrically connecting the plurality of PV cells together in at least one string having a positive terminal and a negative terminal. The method further involves connecting positive and negative conductors to the positive and negative terminals respectively. The method also involves affixing front and back encapsulating sheets on the front and back sides respectively of the array, to form a sub-laminate comprised of the planar array and the front and back encapsulating sheets, the sub-laminate having a first outer perimeter edge, the front and back encapsulating sheets being affixed such that each of the positive and negative conductors has a respective portion extending from the positive and negative terminals respectively, between the front and back encapsulating sheets and such that first and second terminating portions of the positive and negative conductors respectively extend outwardly from the first outer perimeter edge of the sub-laminate to facilitate connection to the positive and negative conductors to an external circuit. The method further involves affixing front and back protectors on opposite sides of the sub-laminate to form a laminate comprising the sub-laminate and the front and back protectors, the front and back protectors having second and third outer perimeter edges respectively generally coterminous with the first outer perimeter edge and defining an outer perimeter edge of the laminate, the first and second terminating portions extending outwardly from the outer perimeter edge of the laminate.
The method may involve causing the first and second terminating portions to extend from opposite edge portions of the outer perimeter edge of the laminate.
The method may involve causing the first and second terminating portions to extend from a common edge portion of the outer perimeter edge of the laminate.
The method may involve electrically connecting subsets of the array of PV cells into separate subset strings, each subset string having a positive terminal and a negative terminal and causing the subset strings to be electrically connected together by respective conductors disposed entirely between the first and second encapsulating sheets, the positive and negative conductors being electrically connected to first and last subset strings of the subset strings that are electrically connected together.
The method may involve electrically connecting subsets of the array of PV cells into separate subset strings, each subset string having a positive terminal and a negative terminal and causing the subset strings to be electrically connected together by respective conductors disposed outside the outer perimeter edge of the laminate, the positive and negative conductors being electrically connected to first and last subset strings of the subset strings that are electrically connected together.
The method may involve surrounding the outer perimeter edge of the laminate with a frame having an integral holder operably configured to hold first and second electrical connectors.
The method may involve causing the first and second terminating portions of the positive and negative conductors to extend into the holder, and connecting the first and second terminating portions to the first and second electrical connectors respectively.
The method may involve connecting the first and second electrical connectors to third and fourth electrical connectors on the holder, the third and fourth electrical connectors having portions externally of the holder to enable the array to be electrically connected to a load.
Surrounding the laminate with a frame may involve connecting a plurality of frame members together such that each of the frame members holds a respective portion of the outer perimeter edge of the laminate.
Connecting the plurality of frame members together may involve corner connectors with openings integrally formed in respective frame members.
The method may involve electrically connecting subsets of the array of PV cells into separate subset strings, each subset string having a positive terminal and a negative terminal.
The method may involve connecting each positive and negative terminal of each string to a respective conductor having a respective terminating portion extending into the holder.
The method may involve connecting respective terminating portions of the conductors to a respective electrical connector disposed in the holder.
The method may involve installing a bypass diode in the holder and electrically connecting the bypass diode to a pair of electrical connectors associated with a subset string of PV cells to protect the subset string of PV cells from excessive electrical current when the subset string is not generating electric current.
The method may involve protecting the electrical connectors in the holder from weather.
The method may involve bending at least one of the first and second terminating portions to extend across a portion of the outer perimeter edge of the laminate and across a portion of a back side of the laminate.
The method may involve receiving a portion of the outer perimeter edge of the laminate in a receptacle of a frame member having a first electrical connector such that the at least one of the first and second terminating portions extends through an opening in the frame member to facilitate connection of the at least one of the first and second terminating portions to the first electrical connector when the outer perimeter edge of the laminate is fully received in the receptacle.
The method may involve connecting at least one of the first and second terminating portions to the electrical connector.
The method may involve holding the first electrical connector in a holder on the frame member.
Holding the first electrical connector may involve holding the first electrical connector in a holder disposed on the frame member to extend away from the back side of the laminate when the outer perimeter edge of the laminate is received in the receptacle.
The method may involve connecting the first electrical connector to a second electrical connector having at least a portion extending out of the holder to facilitate connection of the second electrical connector to a load.
In accordance with another aspect of the invention, there is provided a method of framing a PV module. The method involves surrounding and holding an outer perimeter edge of the PV module with a plurality of frame members. The method also involves surrounding connecting frame members together by receiving portions of frame connector elements in respective frame connectors of adjacent frame members. The method further involves holding causing module holders extending between first and second opposite end portions of respective frame members to hold respective edge portions of the outer perimeter edge of the PV module. The method also involves causing at least one conductor extending from an outer perimeter edge of the PV module to extend into the module holder of one of the plurality of frame members and into an electrical connector disposed in an electrical connector holder on an outer portion of the one of the plurality of frame members.
Causing the conductor to extend into the module holder may involve causing at least one conductor to extend in a continuous curve from the outer edge of the PV module to the electrical connector.
The method may involve connecting the electrical connector to an externally accessible terminal mounted on one of the plurality of frame members to enable the PV module to be connected to a load.
The method may involve covering the electrical connector holder to protect the electrical connectors from weather.
Causing the conductor to extend into the module holder may involve causing a plurality of conductors extending from an outer perimeter edge of the PV module to extend into the module holder of one of the plurality of frame members and into respective electrical connectors disposed in an electrical connector holder on an outer portion of one of the plurality of frame members.
The method may involve connecting the respective electrical connectors to respective externally accessible terminals mounted on one of the plurality of frame members to enable the PV module to be connected to a load.
The method may involve installing a bypass diode in the electrical connector holder and connecting the bypass diode to two adjacent electrical connectors to provide for current bypassing of a string of PV cells in the PV module.
The method may involve covering the electrical connector holder to protect the electrical connectors and the bypass diode from weather.
Other aspects and features of the present invention will become apparent to those ordinarily skilled in the art upon review of the following description of specific embodiments of the invention in conjunction with the accompanying figures.
In drawings which illustrate embodiments of the invention,
Referring to
Each of the positive and negative conductors 22 and 24 has a respective portion 34 and 36 extending from the positive and negative terminals 18 and 20 respectively, between the front and back encapsulating sheets 26 and 28. The positive and negative conductors 22 and 24 have first and second terminating portions 38 and 40 respectively, that extend outwardly from the first outer perimeter edge 32 of the sub-laminate 30.
Front and back protectors 42 and 44 respectively, are disposed on the front and back encapsulating sheets 26 and 28 to form a laminate 46 comprising the sub-laminate 30 and the front and back protectors. The front and back protectors 42 and 44 have second and third perimeter edges 48 and 50 respectively that extend all the way around the front and back protectors respectively and which are generally co-terminus with the first outer perimeter edge 32 of the sub-laminate. Thus, the first outer perimeter edge 32 of the sub-laminate 30 and the second and third outer perimeter edges 48 and 50 define an outer perimeter edge 52 of the laminate 46. The first and second terminating portions 38 and 40 extend outwardly from the outer perimeter edge 52 of the laminate 46.
In the embodiment shown in
Referring to
The PV cells 60 and 62 are connected together using first and second electrodes, shown generally at 66 and 67 of the type generally described in European Patent No. 1,547,158 to Rubin et al.
Referring to
The second electrode 67, is similar to the first electrode 66 and is placed on the front side surface 71 of the second PV cell 62 with non-adhesive embedded portions 92 of wires 94 in contact with the front side surface 71. First ends 96 of the wires 94 are connected together by the bus bar 78 that is in electrical contact with the second ends of the wires 74 of the first electrode 66.
In essence, the first electrode 66 faces upwardly and is in electrical contact with the back side surface 69 of the first PV cell 60 and the second electrode 67 faces downwardly and is in electrical contact with the front side surface 71 of the second PV cell. The first and second electrodes 66 and 67 are connected together by the bus bar 78 and thus connect the back side surface 69 of the first PV cell 60 to the front side surface 71 of the second PV cell 62. This method of connecting adjacent PV cells together is repeated for each adjacent pair of PV cells to connect the PV cells together electrically in a series string.
The first PV cell in a string may be considered to be that PV cell that is electrically nearest the positive terminal of the string and the last PV cell in a string may be considered to be that PV cell that is electrically nearest the negative terminal of the string. Therefore, in the embodiment shown in
Referring to
Referring to
Referring to
Referring back to
Since the back surfaces each of the PV cells in the string is a planar electrode, the orientation of the wires on the electrode that contacts them is irrelevant. Therefore, by placing the final PV cell 132 of the second row such that the screen printed fingers on that cell are at right angles to the screen printed fingers of the final PV cell 130 in the first row, the wires on the electrode extending from the adjacent PV cell 135 can still make contact with the entire back side surface of the final cell 132 in the second row and the wires on the electrode 137 can contact all of the screen printed fingers on the final cell 132 in the second row, and contact the entire back side surface of the final cell 130 in the first row 101.
Alternatively, as shown in
With terminating electrodes 139 and 141 connected to the final PV cells 130 and 132 in each row, the terminating portions 140 and 142 extend parallel to each other. In addition, the terminating portion 140 will act as a negative terminal for the first string portion and the terminating portion 142 will act as a positive terminal for the second string portion. Therefore, to electrically connect the first and second string portions together in series, a strip of copper foil such as shown at 146 is connected such as by soldering to the terminating portions 140 and 142. The use of copper foil for the terminating portions 140 and 142 and to connect the terminating portions together keeps the thickness of the materials used in this area to a minimum, lessening the risk of voids in the laminate 46.
The total number of strings is limited by the size of the PV module. Typically the number of strings will not exceed 10. The number of PV cells per string depends on the generated power and as will be appreciated later, the type of bypass diode that should be sufficient to dissipate heat when the PV cell(s) in the string is (are) shaded. Desirably the total number of 6-inch crystalline silicon PV cells in two interconnected series PV strings should not exceed 24.
Referring to
Referring to
The embodiment of
Referring to
A fragmented cross-sectional view of the first frame member 202 is shown in
The web portion 220 and the outwardly extending portions 227 and 229 are arranged to form a longitudinal channel seen best at 232 in
Still referring to
An opening 240 is provided in the web portion 220 to enable the terminating portion 38 of the positive conductor 22 to be received through the opening 240 when the common edge portion 134 is fully received in the receptacle formed by the surfaces 236 and 238 and the web portion. This enables the terminating portion 38 to extend into the channel 232 formed by the holder 210. A rubber Mylar® or propylene grommet 242, for example, may be installed in the opening 240 to eliminate the possibility that the terminating portion 38 can make electrical contact with the web portion 220, especially where the web portion or the entire first frame member 202 is formed of a metallic material such as an aluminum extrusion. In addition, or alternatively, the terminating portion may be partially covered with an insulating material such as Mylar®, polypropylene or another polymeric material at least at the point it passes through the opening 244, while leaving a suitably sized portion free of insulating material to facilitate connection of the terminating portion to the electrical connector 212. Desirably, the insulating material should be able to withstand a dielectric stress of about 8 kV. Alternatively the frame member 202 may be formed from an insulating material, such as a plastic extrusion, in which case the grommet 242 may not be required for electrical insulation but may be desirable to provide a soft edge on which the terminating portion 38 may rest.
In this embodiment, the first electrical connector 212 is of the type provided by Multi-Contact AG of Basel, Switzerland and includes an opening 244 for receiving the terminating portion 38. Opposing springs 246 and 248 of the electrical connector 212 are disposed inside the opening and are biased towards each other. The terminating portion 38 is pushed into the opening 244 and between the springs 246 and 248 such that the springs grasp opposite sides of the terminating portion and thus secure it mechanically while providing an electrical connection to the terminating portion. A wire shown best at 250 in
Referring back to
Still referring to
The first opening 268 in the first frame member 202 is shown ready to receive a first portion 280 of the corner connector 270. A similar opening 282 of the fourth frame member 208 is shown ready to receive a second portion 284 of the corner connector 270. The first and second portions 280 and 284 of the corner connector 270 are disposed at right angles to each other and the first and fourth frame members have end edges 286 and 288 that are disposed at a 45 degree angle to the longitudinal axes of the first and fourth frame members 202 and 208 such that when the first and second portions 280 and 284 of the corner connector 270 are fully received in the openings 268 and 282 respectively, the end edges 286 and 288 of the corresponding frame members 202 and 208 are in abutment and the frame members are disposed at right angles to each other.
In the embodiment shown, the portions 280 and 284 of the corner connector 270 are formed such that at least one surface thereof has a plurality of grooves, one of which is shown at 292, and ridges, one of which is shown at 294, to facilitate gripping the respective frame member to which the corresponding portion 280 and 284 is associated.
Referring back to
The first frame member 202 described in connection with
The laminates shown in
To facilitate use of the frame members with the laminates shown in
If there is no need to connect the individual strings to external loads or other strings outside the PV module, the externally accessible electrical connector 322 can be eliminated and a wire may be connected between the electrical connectors 285 and 287 to connect the first and second strings 152 and 154 together.
If the laminate shown in
Referring back to
Alternative connector arrangements to those shown in
In this embodiment the fifth and sixth connectors 410 and 412 are connected together by a wire 414. The third and fifth connectors 406 and 410 thus form a first pair 462 of externally accessible connectors at a first side of the PV module and the fourth and sixth connectors 408 and 412 form a second pair 464 of externally accessible connectors at a second, opposite side of the PV module.
A jumper shown generally at 416 may be used at either side of the PV module to jumper the pair 462 or 464 of electrical connectors at that side, if desired. For example, in the embodiment shown, the jumper 416 is used to connect together the first pair 462 so that external electrical access to the module is provided by the second pair 464. Alternatively, external electrical access can be provided by the first pair 462 by simply installing the jumper on the second pair 464.
Referring to
Referring to
In this embodiment, the apparatus further includes third and fourth externally accessible electrical connectors 446 and 448 disposed on opposite sides of the module, adjacent the first and second externally accessible electrical connectors 438 and 440 respectively and connected by a wire 449 to each other. The first and third externally accessible electrical connectors 438 and 446 thus act as a first pair 462 of electrical connectors for the PV module and the second and fourth externally accessible electrical connectors 440 and 448 act as a second pair 464 of electrical connectors for the PV module.
The pairs 462 and 464 of connectors at opposite ends of the PV module permit a jumper such as shown at 416 in
The embodiment shown in
Referring to
Referring to
The jumper 416 may be connected to the pair 462 of connectors on the second module 472 thereby enabling electrical access to the positive and negative terminals of the system of PV modules to be provided by the pair 464 of connectors on the first PV module 470. Referring to
Referring to
Referring to
In this embodiment, the receptacle 502 is formed by forming a generally U-shaped channel in the frame member. The U-shaped channel has first and second parallel leg portions 520 and 522 and a connecting portion 524 extending therebetween. The first and second parallel leg portions 520 and 522 are spaced apart about the same thickness as the laminate 46 so that the edge portion of the laminate is snugly received in the receptacle 502.
In this embodiment, the frame member 500 has a mounting portion 526 adjacent the receptacle 502 for mounting an electrical connector holder 528 to the frame member 500. The mounting portion 526 is disposed generally parallel to the laminate 46 such that when the electrical connector holder 528 is mounted to the mounting portion 526, or integrally formed therewith, the electrical connector holder extends generally outwardly, away from the back side 516 of the laminate 46 as indicated by arrow 530. In this embodiment, the electrical connector holder 528 is integral with the frame member 520 and mounting portion 526 and has a plurality of walls, three of which are shown at 532, 534, and 536 that define a cavity 538 in which the electrical connector 518 is held.
It will be appreciated that the electrical connector holder 528 is positioned on the mounting portion 526 such that at least one of the first and second terminating portions (508) can extend through the first opening 504 and into the electrical connector holder and into the electrical connector held therein.
In this embodiment the electrical connector includes a first terminator 540 for receiving the terminating portion 508 therein, and includes a second terminator shown generally at 542 for receiving a wire 544 therein. First and second externally accessible connectors 546 and 548 are mounted to the wall 536 and lie in a plane 550 that is parallel to a plane of the back side surface 516 of the laminate. The wire 544 is connected to the first externally accessible connector 546 and a second wire 552 is connected to the second externally accessible electrical connector.
It will be appreciated that a mirror image of the structure shown in
In a case where the PV module has more than one string of PV cells, such as 3 strings, the structure shown in
Referring to
In the embodiment shown in
Referring to
In the embodiment shown, bypass diodes such as shown at 630, 632, and 634 are connected between respective connectors of the pairs of electrical connectors associated with respective compartments and thus the bypass diodes are connected across the positive and negative terminating portions of respective strings to thereby protect the respective strings from acting as a current sink in the event the string is shaded.
In the embodiment shown, at least some of the walls defining the compartments have passageways extending between adjacent compartments and in this embodiment walls 596 and 604 have first and second passage ways 640, 642, 644, and 645 respectively. The passage ways 640 and 644 have wires 646 and 648 extending therethrough for connecting the electrical connectors of adjacent compartments together. This facilitates connection of the strings of PV cells in series for example.
Still referring to
Finally, cover members 680, 682, and 684 may be provided to co-operate with flange portions 686, 688, and 690 respectively to seal the first, second and third compartments 612, 614, and 616 respectively to protect the connectors disposed therein and other components disposed therein from weather.
Referring to
The second PV module 704 is configured similarly such that it has a positive externally accessible electrical connector 732 and a negative externally accessible electrical connector 734. Again the remaining connectors 736 and 738 are connected together by a single wire 740.
To connect the first and second PV modules together, a first jumper 750 is connected between the externally accessible electrical connector 674 of the first PV module 702 and the externally accessible electrical connector 732 of the second PV module 704. A second jumper 752 is connected between the remaining adjacent connectors to connect wire 730 to wire 740. In addition, a third jumper 754 is connected between the negative terminal 734 of the second PV module 704 and the other terminal 738 to connect the negative terminal of the second PV module, which now acts as the negative terminal of the overall system, to the wires 730 and 740 to cause the externally accessible electrical connector 756 adjacent the externally accessible electrical connector 654 to act as the negative terminal for the overall system. Connector 654 acts as the positive terminal for the overall system. Because all of the externally accessible connectors are disposed to have a connection axis generally parallel to the plane of the laminates of each of the PV modules 702 and 704, the jumpers 750, 752, and 754 generally lie in a plane parallel to the planes of the PV modules thus do not interfere with the positioning of inside edges 760 and 762 of the PV modules, enabling the inside edges to abut each other and eliminating any need to space apart the PV modules in order to remove any one PV module from the system.
If desired, the inside edge 760 of the first PV module 702 may be provided with small receptacles such as shown at 764 and 766 for receiving corresponding projections 768 and 770 for aligning the first and second PV modules 702 and 704 in a common plane. It will be appreciated that the receptacles 764, 766 and projections 768, 770 are just one of a plurality of ways of aligning the first and second PV modules 702 and 704 in a co-planar arrangement.
Referring to
In this embodiment, each of the electrical connector holders 802, 804, and 806 has a respective end wall 840 and 842 having a frangible portion 844 and 846 that may be broken out, as desired to provide an opening through the corresponding end wall 840 and 842. This facilitates the insertion of conduits such as shown at 850 and 852 between adjacent electrical connector holders such as between the first and second holders 802 and 804 and the second and third holders 804 and 806.
In the embodiment shown, the conduits are provided by rubber grommets having opposed flanges 854 and 856 disposed at opposite ends of a neck portion 858 whereby the flanges are disposed against inside surfaces of walls 842 and 845 respectively and the neck portion 858 extends through the openings created by breaking the frangible portions 844 and adjacent electrical connector holders. The use of rubber grommets as conduits 850 and 852 facilitates installation of the grommets after the separate electrical connector holders 802, 804, and 806 are fastened to the mounting portion 564 and provide generally weather tight seals that prevent moisture ingress.
The electrical connector holders 802, 804, and 806 may further be provided with frangible portions such as shown at 860 and 862 on opposite ends thereof to facilitate selectively mounting externally accessible electrical connectors such as shown at 866 and 867 in frangible portions 860. The frangible portions 860 can be used on the first electrical connector holder 802 and the frangible portions 862 can be used on the third electrical connector holder 806 to facilitate mounting of the first and second pairs of externally accessible electrical connectors 890 and 892 disposed on opposite sides of the PV module.
Wires such as shown at 894 and 896 act to connect respective strings of PV cells in series and these wires extend through the conduits 850 and 852 between the first and second electrical connector holders 802 and 804 and the second and third electrical connectors 804 and 806 respectively. In addition a wire 898 is connected between one connector of each pair 890 and 892 of the externally accessible electrical connectors to provide for use of the PV module in a manner similar to that depicted in
Finally, each electrical connector holder 802, 804, and 806 is provided with a respective cover 900, 902, and 904 to provide for generally weather tight sealing of the corresponding electrical connector holders. It will be appreciated that the use of the separate electrical connector holders 802, 804, and 806 in
In each of the embodiments shown herein it will be appreciated that conductors connected to positive and negative terminals of strings of PV cells are brought out through the outer perimeter edge of the laminate with which they are associated and terminated in an electrical connector disposed on a frame member of a frame surrounding the laminate. This eliminates the need for a junction box as is used in the prior art and allows a bypass diode to be mounted at an edge of the PV module. Furthermore, especially where the frame member is made of a heat conductive material, heat generated in the bypass diode is conducted to the electrical connectors which are connected to the frame member, which facilitates dissipation of heat through the frame and any mounting apparatus to which is it connected. This may be contrasted with the dissipation of heat through a junction box mounted on the back of the PV module as in the prior art, where this type of heat dissipation can significantly increase the temperature of the PV cells adjacent the junction box.
While specific embodiments of the invention have been described and illustrated, such embodiments should be considered illustrative of the invention only and not as limiting the invention as construed in accordance with the accompanying claims.
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/CA2007/002301 | 12/18/2007 | WO | 00 | 7/26/2010 |
