Patent Application
20160226438
The present invention is directed to photovoltaic systems and manufacturing processes and apparatus thereof. In particular, the present invention provides an apparatus and method for using diode protection for a high-density solar module.
As the population of the world has increased, industrial expansion has led to a corresponding increased consumption of energy. Energy often comes from fossil fuels, including coal and oil, hydroelectric plants, nuclear sources, and others. As merely an example, the International Energy Agency projects further increases in oil consumption, with developing nations such as China and India accounting for most of the increase. Almost every element of our daily lives depends, in part, on oil, which is becoming increasingly scarce. As time further progresses, an era of “cheap” and plentiful oil is coming to an end. Accordingly, other and alternative sources of energy have been developed.
In addition to oil, we have also relied upon other very useful sources of energy such as hydroelectric, nuclear, and the like to provide our electricity needs. As an example, most of our conventional electricity requirements for home and business use comes from turbines run on coal or other forms of fossil fuel, nuclear power generation plants, and hydroelectric plants, as well as other forms of renewable energy. Often times, home and business use of electrical power has been stable and widespread.
Most importantly, much if not all of the useful energy found on the Earth comes from our sun. Generally all common plant life on the Earth achieves life using photosynthesis processes from sunlight. Fossil fuels such as oil were also developed from biological materials derived from energy associated with the sun. For human beings including “sun worshipers,” sunlight has been essential. For life on the planet Earth, the sun has been our most important energy source and fuel for modern day solar energy.
Solar energy possesses many desirable characteristics; it is renewable, clean, abundant, and often widespread. Certain technologies developed often capture solar energy, concentrate it, store it, and convert it into other useful forms of energy.
Solar panels have been developed to convert sunlight into energy. For example, solar thermal panels are used to convert electromagnetic radiation from the sun into thermal energy for heating homes, running certain industrial processes, or driving high-grade turbines to generate electricity. As another example, solar photovoltaic panels are used to convert sunlight directly into electricity for a variety of applications. Solar panels are generally composed of an array of solar cells, which are interconnected to each other. The cells are often arranged in series and/or parallel groups of cells in series. Accordingly, solar panels have great potential to benefit our nation, security, and human users. They can even diversify our energy requirements and reduce the world's dependence on oil and other potentially detrimental sources of energy.
Although solar panels have been used successfully for certain applications, there are still certain limitations. Solar cells are often costly. Depending upon the geographic region, there are often financial subsidies from governmental entities for purchasing solar panels, which often cannot compete with the direct purchase of electricity from public power companies. Additionally, the panels are often composed of costly photovoltaic silicon bearing wafer materials, which are often difficult to manufacture efficiently on a large scale, and sources can be limited.
Therefore, it is desirable to have novel system and method for manufacturing solar panels.
The present invention is directed to photovoltaic systems and manufacturing processes and apparatus thereof. In particular, the present invention provides an apparatus and method for using diode protection for a high-density solar module. There are other embodiments as well.
In an example, a solar module apparatus is provided. The apparatus has a plurality of strings, each of the plurality of strings being configured in a parallel electrical arrangement with each other and a plurality of photovoltaic strips forming each of the plurality of photovoltaic strings. The apparatus has a first end termination configured along a first end of each of the plurality of strings and a second end termination configured along a second end of each of the plurality of strings. The module has an equivalent diode device configured between the first end termination and the second end termination such that one of the plurality of photovoltaic strips associated with one of the plurality of strings when shaded causes the plurality of strips (“Shaded Strips”) associated with the one of the strings to cease generating electrical current from application of electromagnetic radiation, while a remaining plurality of strips, associated with the remaining plurality of strings, each of which generates a current that is substantially equivalent as an electrical current while the Shaded Strips are not shaded, and the equivalent diode device between the first terminal and the second terminal for the plurality of strips is configured to turn-on to by-pass electrical current through the equivalent diode device such that the electrical current that was by-passed traverses the equivalent diode device coupled to the plurality of strips that are configured parallel to each other.
Many benefits can be achieved by ways of the present invention. As an example, the present module can be made using conventional process and materials. Additionally, the present module is more efficient than conventional module designs. Furthermore, the present module, and related techniques provides for a more efficient module usage using by-pass diodes configured with multiple zones of solar cells. Depending upon the example, there are other benefits as well.
A further understanding of the nature and advantages of the present invention may be realized by reference to the remaining portions of the specification and the drawings.
The present invention is directed to photovoltaic systems and manufacturing processes and apparatus thereof. There are other embodiments as well.
Embodiments of the present invention provide system and methods for manufacturing high density solar panels. Embodiments of the present invention use overlapped or tiled photovoltaic strip elements to increase the amount of photovoltaic material, thereby increasing an amount of power, while reducing an amount of series resistance losses in the solar panel. It is noted that specific embodiments are shown for illustrative purposes, and represent examples. One skilled in the art would recognize other variations, modifications, and alternatives.
Although orientation is not a part of the invention, it is convenient to recognize that a solar module has a side that faces the sun when the module is in use, and an opposite side that faces away from the sun. Although, the module can exist in any orientation, it is convenient to refer to an orientation where “upper” or “top” refer to the sun-facing side and “lower” or “bottom” refer to the opposite side. Thus an element that is said to overlie another element will be closer to the “upper” side than the element it overlies.
While the above is a complete description of specific embodiments of the invention, the above description should not be taken as limiting the scope of the invention as defined by the claims.
In an example, a solar module is shown. The module has an array of solar cells. The array can be N by M, where N is an integer of 1 and greater and M is an integer of 2 and greater. In an example, the module has a plurality of zones dividing the array of solar cells. In an example, the zones are numbered from 1 through R, where R is 4 and greater. Each of the plurality of zones is in series with each other in an example. As shown, the solar module has three zones each of which is connected to each other in series.
As shown, the module has a plurality of photovoltaic strings dividing each of the plurality of zones. Each of the plurality of photovoltaic strings is in parallel with each other. In an example, the plurality of photovoltaic strings are numbered, respectively, from 2 to 12. As shown in this example, each zone has six strings, which are coupled to each other.
As shown, the module has a plurality of photovoltaic strips forming each of the plurality of photovoltaic strings. As shown, the plurality of strips range in number from 2 to 30. Each of the plurality of strips is configured in a series arrangement with each other.
As also shown, a first bus bar and a second bus bar are configured on each of the zones of the solar cells. In this example, four (4) bus bars are illustrated. A first and second bus bar are configured to the first zone. The second and a third bus bar are configured to a second zone.
The third and a four bus bar are configured to the third zone. As used herein, the terms “first” “second” “third” or “fourth” do not necessarily imply order, and should be interpreted under ordinary meaning. In an example, an equivalent diode device is configured between the first bus bar and the second bus bar for a particular zone. Each zone has an equivalent diode device, as shown.
As shown, one of the plurality of photovoltaic strips associated with one of the plurality of strings and associated with a first plurality of zones is shaded. The one shaded strip causes the plurality of strips (“Shaded Strips”) associated with the one of the strings to cease generating electrical current from application of electromagnetic radiation associated one of the strings. All of the remaining plurality of strips, associated with the remaining plurality of strings in the zone, each of which generates a current that is substantially equivalent as the current while the Shaded Strips are not shaded. The diode device between the first bus bar and the second bus bar for the plurality of strips is configured to turn-on to by-pass electrical current from the Shaded Strips through the diode device and the electrical current that was by-passed traverses an equivalent diode device coupled to the plurality of strips associated with a second plurality of zones.
As shown, six of the plurality of photovoltaic strips associated with one of the plurality of strings and associated with a first plurality of zones is shaded. The shaded strips causes the plurality of strips (“Shaded Strips”) associated with the one of the strings to cease generating electrical current from application of electromagnetic radiation associated one of the strings. All of the remaining plurality of strips, associated with the remaining plurality of strings in the zone, each of which generates a current that is substantially equivalent as the current while the Shaded Strips are not shaded. The diode device between the first bus bar and the second bus bar for the plurality of strips is configured to turn-on to by-pass electrical current from the Shaded Strips through the diode device and the electrical current that was by-passed traverses an equivalent diode device coupled to the plurality of strips associated with a second plurality of zones.
In an example, the plurality of strings can be numbered from 2 to 12, while six is shown in this illustration. Each of the plurality of strings is configured in a parallel electrical arrangement with each other. In an example, the plurality of photovoltaic strips forms each of the plurality of photovoltaic strings. The plurality of strips can range from 2 to 30 such that each of the plurality of strips is configured in a series arrangement with each other. In an example, the zone has a first end termination configured along a first end of each of the plurality of strings. In an example, the first end termination is a first terminal. In an example, the second end termination is configured along a second end of each of the plurality of strings. In an example, the second end termination is a second terminal.
In an example, an equivalent diode device is configured between the first end termination and the second end termination such that one of the plurality of photovoltaic strips associated with one of the plurality of strings when shaded causes the plurality of strips (“Shaded Strips”) associated with the one of the strings to cease generating electrical current from application of electromagnetic radiation. All of the remaining plurality of strips, associated with the remaining plurality of strings, each of which generates a current that is substantially equivalent as an electrical current while the Shaded Strips are not shaded. The equivalent diode device between the first terminal and the second terminal for the plurality of strips is configured to turn-on to by-pass electrical current through the equivalent diode device such that the electrical current that was by-passed traverses the equivalent diode device coupled to the plurality of strips that are configured parallel to each other. In an example, the plurality of strings is provided in a zone. As previously noted, one zone is among a plurality of zones to form the solar module.
In an example, the solar module is configured to generate from 100 to 600 Watts. Also, the equivalent diode characterized as a plurality of individual diode devices each of which protects a string among the plurality of strings. Of course, there can also be other variations, alternatives, and modifications.
In an example, the equivalent diode device is a sum of individual diode devices coupled to each of the plurality of strips in each of the plurality of strings in each zone.
In an example, each of the plurality of strips comprises a thickness of photovoltaic material comprising a front bus bar and a back bus bar. In an example, the front bus bar is provided along a first edge region and the back bus bar being provided along a second edge region.
In an example, each of the plurality of strips comprises a thickness of photovoltaic material comprising a front bus bar and a back bus bar. In an example, the front bus bar is provided along a first edge region and the back bus bar being provided along a second edge region. In an example, each of the plurality of strips is associated with one of the plurality of strings. In an example, each of the plurality of strings is associated with one of the plurality of strings being in an overlapped configuration to physically and electrically configure the string.
In an example, each of the plurality of strips comprises a thickness of photovoltaic material comprising a front bus bar and a back bus bar. In an example, the front bus bar is provided along a first edge region and the back bus bar being provided along a second edge region. In an example, each of the plurality of strips is associated with one of the plurality of strings. In an example, each of the plurality of strings associated with one of the plurality of strings being in an overlapped configuration to physically and electrically configured to the string. In an example, each of the plurality of strips is configured from a silicon based mono-crystalline or multi-crystalline solar cell.
In an example, the array of solar cells configured to generate 300 to 450 Watts. In an example, each of the zones is configured to generate at least 70 Watts. In an example, each of the strips is configured to generate at least 0.8 Watt.
In an example, the module further comprising a pair of substrate members configured to sandwich the array of solar cells, at least one of the substrate members being a transparent material. In an example, the array of solar cells is operable at a maximum power of the array of solar cells minus a power amount associated with the Shaded Strips.
In an example, the module further comprising a power output equivalent to a maximum power rating less an amount equivalent to the string associated with the Shaded Strips. In an example, the module further comprising a power output equivalent to a maximum power rating less an amount equivalent to more the one of the strings associated with the Shaded Strips. In an example, the module further comprising a plurality of electrical strings, each of the electrical stings being configured to form an equivalent strip provided by a plurality of strips from a plurality of stings connected in parallel to each other.
Further details of a tiled or shingled photovoltaic strip arrangement can be found in U.S. Design Application No.: 29/509,179, filed Nov. 14, 2014, titled “TILED SOLAR CELL DESIGN,” (Our File No.: A906RO-018000US), commonly owned, and hereby incorporated by reference herein. Each of the strips is configured as a rectangular shape free from any visible and separate bus-bars. Of course there can be variations.
In an example, the solar apparatus is configured as parallel array of photovoltaic strips. The apparatus has a first array of photovoltaic strips. In an example, the first array is defined by one photovoltaic strip by n strips. In an example, the plurality of photovoltaic strips are arranged in series in an edge connected configuration and configured in tiled manner and/or layered manner and/or off-set stacked manner. In an example, the apparatus has a second array of photovoltaic strips. The second array is defined by one photovoltaic strip by n strips. In an example, the plurality of photovoltaic strips are arranged in series in an edge connected configuration and configured in a tiled manner and/or layered manner and/or off-set stacked manner. The apparatus has a first electrode member coupling a positive contact region of each of the first array of photovoltaic strips and the second array of photovoltaic strips and a second electrode member coupling a negative contact region of each of the first array of photovoltaic strips and the second array of photovoltaic strips. The apparatus has a diode device configured to the first electrode member and the second electrode member. The first array and the second array are configured to form a parallel string of photovoltaic strips.
In an example, the apparatus has a third array of photovoltaic strips. The third array is defined by one photovoltaic strip by n strips. In an example, the plurality of photovoltaic strips are arranged in series in an edge connected configuration; and a fourth array of photovoltaic strips. The fourth array is defined by one photovoltaic strip by n strips. In an example, the plurality of photovoltaic strips are arranged in series in an edge connected configuration. The first electrode member coupling a positive contact region of each of the third array of photovoltaic strips and the fourth array of photovoltaic strips; and the second electrode member coupling a negative contact region of each of the third array of photovoltaic strips and the fourth array of photovoltaic strips. The first array, the second array, the third array, and the fourth array are configured to form a parallel string of photovoltaic strips.
In an example, each of the photovoltaic strips comprises a width, a length, and a thickness, each of the photovoltaic strips comprising a first contact region and a second contact region. Each of the strips is configured on opposite edges of each other. The first contact region is along a top side of a first edge and the second contact region is along a bottom side of a second edge, which is on the opposite spatial side of the first edge. In an example, the first contact region comprises a first side region having an aluminum bus bar member, while an opposite has no aluminum material.
In an example, the equivalent diode device can be Schottky Barrier Rectifiers By-Pass Diode, or others. The device can have a 20SQ040, “Bypass Diodes for Solar Modules—Schottky Barrier Rectifiers Bypass,” manufactured by Dioden, Lite-on Semiconductor Corp, or others. In an example, the equivalent diode device is a metal of silicon rectifier, majority carrier conduction, has a guard ring for transient protection, low power loss, high efficiency, high surge and current capability, low VF, among other features. The diode is configured to a JEDEC R-6 molded plastic. The diode has a low forward voltage drop of 0.4V to 0.6V, and a maximum DC blocking voltage of 40-45V. Other features are included in a data sheet of such diode by either Lite-on Semiconductor Corp, or others, which are incorporated by reference herein.
In an example, the present invention provides a longer solar module and related methods. One or more of the following benefits and/or features can achieved:
Further details of the aforementioned features can be found throughout the present specification and more particularly below.
In an example, the present module has an increased size relative to standard solar modules. With traditional 156 mm cells, a larger module can be obtained by making the module longer or wider. Increasing the module size is a challenge in either direction. If the module gets longer by one cell, then the module has to grow by 156 mm. Now, instead of 24 cells per diode it will become 26. This is not usually possible because the reverse bias breakdown voltage of the cell will be exceeded during shading conditions, which will require implanting a costly diode scheme.
If the module were to become wider, it would have to become wider by 156×2 mm. This is because most modules have a loop that is 12 cells by 2 rows. This is needed so that the diode wiring stays simple. It is possible to make it one cell wider but it is still a 156 mm step. Many times single axis horizontal trackers, like the NEXTracker SPT manufactured by NEXTracker, Inc., have a defined width in which they can mount modules. In the NEXTracker case the optimal width is between 990 mm and 1010 mm per module. This allows 8 modules to be mounted on a single segment. If the module width increases, then either only 7 modules will fit on the tracker or the tracker will have to be redesigned to be wider. In either case the cost of the tracker would go up.
In an alternative example, the present module is configured to be longer than conventional. Beyond the diode problems that were highlighted above, the other issue with longer modules is that the module will have greater wind loading. This is an additional cost to the tracker and reduces its performance.
A feature of the present module is that we can increase the length in smaller segments than the 156 traditional cells size. This means that we can grow our module in much smaller increments without significantly increase the system costs. This allows the present module to increase the power of the module without inflicting a penalty on the tracker costs. In an example, the present technique allows taking an industry standard module, increase the area (length) by 7% and have a resulting power increase of 15% with the HD module design.
In an alternative example, the present technique also provides for desired module voltages. In an example, a way for cost reductions in installing systems is to reduce wiring and the associated costs of circuit protection and combiner boxes. In an example, the number of modules configured on single circuit (string) are limited by the DC voltage rating of the system. This is usually 600 VDC or 1000 VDC. Solaria's HD module is being designed for 1500 VDC. When going from 600V to 1000V to 1500V the system costs are reduced significantly. The number of modules in a string is calculated by determining the lowest temperature the module will experience in a location and then adding up the open circuit voltages of the modules. Thus a 1000V system with 46.1V modules in a location could be expected to have a maximum of 21 modules on a string (1000/46.1=21.7).
Usually as modules increase in size, the module voltage goes up. An example of this is that a 60 cell module would typically have an open circuit voltage of 38.4V. A 72 cell module made with the same cells would 46.1V. If the number of cells increased to make the module 15% more powerful than the voltage would increase to 53V. In this case the 1000V string would only be able to accommodate 18 modules (1000/53=18.9). This would result in huge costs increases for the system.
In an example, the present technique allows for cutting a cell into five (⅕) strips. The strips are then made into strings. In an example, six (6) strings are connected in parallel. In doing this, the voltage of the string is reduced by ⅙ while increasing the current by ⅙. This results in our 15% more powerful module having an open circuit voltage of 44.2V. This results in a 1000V string of 22 modules (1000/44.2=22.6). Thus we are able to significantly improve the system economics by providing both a more powerful module and more modules per string.
This benefit is dramatically improved when the module is rated for a 1500V system. In this case we can put up to 33 modules on a string. Usually this is an even number so it is shown as 32 modules.
In an example, large systems often face inefficiencies from soiling issues. That is, soil, snow, or other mechanical debris accumulates along edges of the solar module. In an example, uneven soiling is often an issue with large systems. This tends to accumulate on either end of the module. At the module is rotated during tracking the soiling tends to be trapped by the frame. For traditional module this has a huge effect. The way the strings are laid out means that the whole module is affected when the cells are shaded.
In conventional modules, the whole module is affected by the soiling on the tracker. By using variable diode protection we can limit the effect of soiling. In the case shown above, only 8.3% of the module is affected by the soiling. This has a huge impact on the energy performance of the system, which results in a huge advantage of our module design.
In an example, on a sunny day, typically 15% or more of the sun's energy is delivered through diffuse light. The sun's radiation can generally be broken up into two components, direct and diffuse light. Direct light is the light that travels directly from the sun to the module without any reflections. Diffuse light is usually the result of light that has had at least one reflection. Trackers are designed to capture as much of the direct light as possible without shadowing each other. However, trackers do shadow each other when it comes to diffuse light.
When a single axis tracker is horizontal (facing straight up), then the module can capture all the diffuse light. However when the tracker rotates away from the horizontal position, the bottom of the module will become shaded with regards to diffuse light from the modules on the tracker in front. The total illumination on the module will become non-uniform.
Similar to the soiling discussion above, the non-uniform light will cause all the cells to be limited in a traditional module. However, the present diode scheme will allow each section of module to operate at its maximum potential. Again this will result in improved energy yield, which is beneficial.
Further details of the present module that can overcome these limitations are described throughout the present specification and more particularly below.
In an example of the present invention a string configured along an upper and/or lower portion of the solar module can be assembled using a shorter string, than those located in the center region. Beneficial results have been observed using the shorter string in operating a solar tracker system with the present module. Further details of the present module can be found throughout the present specification and more particularly below.
In an example, the present module has a plurality of individual diode devices. Each of the plurality of individual diode device is coupled to each of the plurality of strips in each of the plurality of strings in each zone. In an example, at least one of the individual diode devices coupled to one of the plurality of strips to form a first edge string configured along the first edge of the array of solar cells, and characterized by a number of stripes N, where N is fewer in numbers than the plurality of strips forming a string within a center region of the array of solar cells. In an example, at least one of the individual diode devices coupled to one of the plurality of strips to form a second edge string configured along the second edge of the array of solar cells, and characterized by a number of stripes M, where M is fewer in numbers than the plurality of strips forming a string within a center region of the array of solar cells. Fewer strips leads to a shorter string region, leading to a smaller area of current rerouting upon shading of either the an upper or lower region of the solar module, which is often plagued with soiling limitations. Soiling can come from dirt or soil particles, snow, or other mechanical debris that can accumulate along edges of the solar module during use of the module on a tracker system.
In an example, each of the first edge string and the second edge string is characterized by an edge spatial width, the spatial width being narrower than a spatial width of the string configured within the center region of the solar array. Further details of the present module can be found throughout the present specification and more particularly below.
It is understood that the examples and embodiments described herein are for illustrative purposes only and that various modifications or changes in light thereof will be suggested to persons skilled in the art and are to be included within the spirit and purview of this application and scope of the appended claims.
This application is a continuation in part of and claims priority to U.S. Ser. No. 14/609,307 filed Jan. 29, 2015 (Attorney Docket No. A906RO-018100US), commonly assigned, and hereby incorporated by reference herein.
| Number | Date | Country | |
|---|---|---|---|
| Parent | 14609307 | Jan 2015 | US |
| Child | 14869130 | US |
