JP6010694B2 - Solar power generation system without bypass diode - Google Patents

Description

(Cross-reference to related applications)
This application claims priority to US patent application Ser. No. 13 / 543,297, filed July 6, 2012, entitled “PHOTOVOLTAIC POWER GENERATION SYSTEM FREE OF BYPASS DIODES”. All of the above applications are incorporated herein by reference.

(Statement of government rights)
The present invention was developed under the contract DE-AC04-94AL85000 between the Sandia Corporation and the US Department of Energy. The US government has certain rights in the invention.

(background)
Along with the use of fossil fuels to generate electricity, environmental concerns regarding the non-renewable nature of such fossil fuels are increasing the demand for alternative energy sources. Exemplary power systems that utilize renewable energy resources include, among others, solar power systems, wind power systems, hydropower systems, and geothermal power systems.

  Conventional photovoltaic systems, particularly those utilized to provide power to a residence, include a solar panel that includes a plurality of relatively large silicon photovoltaic cells (eg, about 6 inches × 6 inches). . For example, a single solar panel can include about 72 batteries. A solar cell is manufactured to output a certain voltage (eg, 0.6 volts for a silicon cell) that is approximately constant regardless of the amount of solar radiation of a particular wavelength received at the solar cell, It is electrically connected in series within the solar panel so that the solar panel produces about 40 volts. A typical residential solar system includes several solar panels (eg, 5-10), which are electrically connected in series, whereby hundreds of batteries are electrically connected in series. Collectively, the result is to output a voltage approximately equal to the sum of the voltages of the individual cells. However, it should be noted that when solar cells and panels are electrically arranged in series, the current must be equal across each of the cells within each of the solar panels.

  Since the current of the photovoltaic cell is proportional to the light incident on the cell, if one cell in the series connection receives a low light level, the entire series connection has a low current. Thus, a typical photovoltaic system configuration, including several solar panels, can cause severe current reduction (and when a battery or part of a battery has a low light level (eg, due to shadows) Power output reduction). In many cases, when a photovoltaic system is installed on a residence or other building, trees or other obstacles may be present in the vicinity, and thus shadows of at least some of the modules may occur frequently. .

  When a shadowed pattern occurs across a photovoltaic system, the solar cell can be severely damaged unless a protective electrical device is installed. For example, if a single solar cell is shaded by an obstacle and all other cells in the photovoltaic system are illuminated, the single cell is reversed to support the current generated by the other cells. Can be driven to directional breakdown. In current photovoltaic installations, the battery current is about 5 amps, and silicon batteries have a breakdown voltage of about 60 volts or more, depending on the battery design and manufacturing technique used to produce the battery. . Since breakdown is not a uniform process across large batteries, a relatively large current (5 amperes) and a relatively large power (above 100 watts) will cause the device to fail in either a short circuit or open state. And cause improper operation and permanent damage to batteries, panels, and / or equipment.

  In order to prevent the photovoltaic cells in the photovoltaic installation from being driven by reverse breakdown, bypass diodes are selectively positioned across the cells, thereby diverting current from the cells without photocurrent. , Prevent such batteries from entering the breakdown region. However, the use of the bypass diode consumes space in the photovoltaic power generation facility, is relatively expensive, and increases the assembly time of the solar panel. In addition, the use of bypass diodes can result in excessive power production losses because each bypass diode typically protects one third of the cells in the panel (eg, typically three bypass diodes in the panel). Exist). Thus, if one battery is shaded, power production from all of the batteries covered by the bypass diode will be lost.

(wrap up)
The following is a brief summary of the subject matter described in more detail herein. This summary is not intended as a limitation on the scope of the claims.

  Described herein are various techniques related to photovoltaic systems. More specifically, a photovoltaic system without any bypass diode is described herein. In an exemplary embodiment, a photovoltaic system can include at least one solar panel (also referred to as a module) that consists of a plurality of photovoltaic sub-modules. Each photovoltaic sub-module can have an operating voltage between 50 volts and 2000 volts and a plurality of panels, and thus can be electrically arranged in parallel. The nominal operating voltage of solar panels is generally in the range of 200 volts to 500 volts, which is substantially lower than conventional commercial inverters in the United States because the current daily regulatory limit is 600 volts. However, the appended claims are not limited by such regulatory limits. Further, in an exemplary embodiment, the photovoltaic submodule can be less than 30 cm wide and less than 30 cm long, although other sized submodules are also envisioned. A parallel arrangement of photovoltaic sub-modules in a solar panel ensures that a relatively large amount of power is not dissipated across one of such sub-modules when a particular sub-module or set of sub-modules is shaded To prevent it.

  In another exemplary embodiment, each photovoltaic sub-module can comprise a plurality of groups of connected batteries, each group configured to output 2 volts to 3 volts, and at least one of the groups The subsets are electrically connected in series. Each group of connected cells in the photovoltaic module can comprise a plurality of strings of photovoltaic cells, the strings of photovoltaic cells being electrically connected in parallel. Each photovoltaic string can include a plurality of photovoltaic cells electrically connected in series. This series / parallel / series / parallel arrangement of photovoltaic cells in a solar panel allows a relatively large amount of current to be arbitrary when the cell is accidentally shielded (while other cells in the solar panel are illuminated) To prevent it from being driven through a single photovoltaic cell.

  According to one embodiment, the photovoltaic cell utilized to construct the solar panel can be a microsystem capable photovoltaic cell that is configured to have an operating voltage of 0.3 volts to 2.0 volts. Because of the relatively large number of cells that can be included in a given solar panel (eg, more than 30,000 cells), it dissipates across a single cell for almost any potential shadow pattern on the solar panel The amount of power that can be done will not cause damage to any given battery, even if the battery is operating in reverse breakdown. Therefore, the solar panels described herein are intended to ensure that the batteries in the solar panel are not damaged when one or more of such batteries are operating in reverse breakdown. There is no need to include a bypass diode, which is conventionally employed. This is because within the solar panels described herein, power dissipation across a single cell does not exceed a threshold that would damage the cell even if such a cell is at breakdown. That is, the battery can continue to operate in reverse breakdown indefinitely without sustaining damage because the amount of current that can be directed to any battery in the solar panel is relatively small.

As described above, the photovoltaic cell in the solar panel can be a microsystem compatible battery. According to certain embodiments, such a battery can be a III-V battery, such as a gallium arsenide battery, an indium gallium phosphide battery, or an indium gallium arsenide battery. In other exemplary embodiments, the photovoltaic cell can comprise a silicon cell. In still other embodiments, the photovoltaic cell can comprise a germanium photovoltaic cell. According to yet another exemplary embodiment, the solar panel can comprise a multi-junction photovoltaic cell, and each multi-junction photovoltaic cell can comprise a plurality of photovoltaic cells of different band gaps. According to one embodiment, each photovoltaic cell in the multi-junction photovoltaic cell is electrically connected integrally in series such that the operating voltage of the multi-junction photovoltaic cell is equal to the sum of the operating voltages of the individual microsystem-capable photovoltaic cells therein. Can be connected. In another exemplary embodiment, the individual types of photovoltaic cells can optionally be arranged in series and in parallel, with some photovoltaic cells arranged in series having a desired output or intermediate voltage. Can depend on.
This specification also provides the following items, for example.
(Item 1)
A photovoltaic sub-module,
The photovoltaic sub-module comprises a plurality of microsystem-compatible photovoltaic cells that are electrically connected to each other, each microsystem-compatible photovoltaic cell within the plurality of microsystem-compatible photovoltaic cells being only 2 centimeters high and 2 centimeters A photovoltaic sub-module that is the size of the width and the photovoltaic sub-module is free of any bypass diodes.
(Item 2)
The first group further comprises a first string of microsystem-capable photovoltaic cells and a second string of microsystem-capable photovoltaic cells, the cells in the first string of microsystem-capable photovoltaic cells. Are electrically connected in series, the cells in the second string of microsystem-compatible photovoltaic cells are electrically connected in series, and the first string and the second string are electrically connected in parallel. The photovoltaic sub-module according to item 1, wherein the photovoltaic sub-module is connected to.
(Item 3)
A second group, the second group comprising a third string of microsystem-capable photovoltaic cells and a fourth string of microsystem-capable photovoltaic cells, wherein the cells in the third string of the microsystem-capable photovoltaic cells Are electrically connected in series, the cells in the fourth string of microsystem-compatible photovoltaic cells are electrically connected in series, and the third string and the fourth string are electrically connected in parallel. The photovoltaic sub-module of claim 2, wherein the first group is electrically coupled in series with the second group.
(Item 4)
The photovoltaic submodule according to item 1, wherein the photovoltaic submodule outputs 500 volts to 2000 volts.
(Item 5)
And further comprising a first group, wherein the first group comprises:
A first string of microsystem compatible photovoltaic cells;
A second string of microsystem-compatible photovoltaic cells, wherein the cells in the first string of microsystem-compatible photovoltaic cells are electrically connected in series, and the batteries in the second string of microsystem-compatible photovoltaic cells are A second string electrically connected in series;
A power management integrated circuit electrically connected to a first string of microsystem-compatible photovoltaic cells and a second string of microsystem-compatible photovoltaic cells, wherein the power management integrated circuit is at least partially Based on the voltage output by the first string of system enabled photovoltaic cells and the second string of said microsystem enabled photovoltaic cells, outputs a predetermined amount of power and dynamically based on external operating conditions or system operating commands Power management integrated circuit, which is adjustable to
The photovoltaic submodule according to item 1, comprising:
(Item 6)
The photovoltaic sub-module of item 1, wherein the photovoltaic sub-module is less than 30 centimeters long and less than 30 centimeters wide.
(Item 7)
The photovoltaic submodule according to item 1, wherein at least one photovoltaic cell of the plurality of photovoltaic cells has both positive and negative electrical contacts on a back side of the at least one photovoltaic cell.
(Item 8)
The photovoltaic submodule according to item 1, wherein the plurality of microsystem compatible batteries include at least one of an InGaP battery or an InGaAs battery.
(Item 9)
The photovoltaic submodule according to item 1, wherein the plurality of microsystem-compatible batteries comprise GaAs batteries.
(Item 10)
The photovoltaic submodule according to item 1, wherein the plurality of microsystem-compatible batteries include at least one of a Ge battery and a Si battery.
(Item 11)
The photovoltaic submodule according to item 1, wherein each of the plurality of multi-junction batteries includes the plurality of photovoltaic cells.
(Item 12)
Item 2. The photovoltaic submodule of item 1, comprising a solar panel.
(Item 13)
13. The photovoltaic submodule of item 12, wherein the solar panel is free of any bypass diode.
(Item 14)
14. The photovoltaic submodule of item 13, wherein the solar panel is non-planar.
(Item 15)
A solar panel, the solar panel
A first photovoltaic submodule, wherein the first photovoltaic submodule comprises a first plurality of photovoltaic cells;
A second photovoltaic sub-module, wherein the second photovoltaic sub-module comprises a second plurality of photovoltaic cells, the first photovoltaic sub-module and the second photovoltaic sub-module The modules are electrically connected in parallel, and the solar panel is connected to a second photovoltaic sub-module, without any bypass diodes
A solar panel.
(Item 16)
Item 16. The solar panel of item 15, configured to output 200 volts to 600 volts.
(Item 17)
16. The solar panel of item 15, wherein the first photovoltaic sub-module is less than 30 centimeters long and less than 30 centimeters high.
(Item 18)
The first photovoltaic submodule is:
A first photovoltaic cell group, wherein the first photovoltaic cell group comprises:
A first string of microsystem compatible photovoltaic cells;
A second string of microsystem-capable photovoltaic cells, wherein the cells in the first string of microsystem-capable photovoltaic cells are electrically connected in series, and the cells in the second string of microsystem-capable photovoltaic cells are A first string of the microsystem capable photovoltaic cells and a second string of the microsystem capable photovoltaic cells electrically connected in series, and a second string electrically connected in parallel;
The solar panel according to item 15, comprising:
(Item 19)
19. The solar panel of item 18, wherein a plurality of multi-junction photovoltaic cells comprises a first string of the microsystem capable photovoltaic cells and a second string of the microsystem capable photovoltaic cells.
(Item 20)
A solar panel, the solar panel
A plurality of photovoltaic submodules, wherein the plurality of photovoltaic submodules are electrically connected in parallel with each other, and each photovoltaic submodule is electrically connected in series with each other. A solar panel comprising at least one of a III-V photovoltaic cell or a plurality of silicon cells electrically connected in series with each other, the solar panel being free of any bypass diodes.

  Other aspects will be appreciated upon reading and understanding of the accompanying figures and descriptions.

FIG. 1 illustrates an exemplary solar panel comprising a plurality of photovoltaic submodules. FIG. 2 illustrates an exemplary photovoltaic sub-module comprising a plurality of photovoltaic cell groups of electrically connected photovoltaic cells. FIG. 3 illustrates an exemplary group of photovoltaic cells comprising a plurality of strings of photovoltaic cells. FIG. 4 illustrates another exemplary solar panel consisting of a plurality of photovoltaic sub-modules, each consisting of a plurality of individual groups of photovoltaic cells electrically connected. FIG. 5 illustrates an exemplary multi-junction microsystem capable photovoltaic cell. FIG. 6 illustrates an exemplary methodology for constructing a solar panel that does not include a bypass diode. FIG. 7 illustrates an exemplary methodology for constructing a solar panel that does not include a bypass diode.

(Detailed explanation)
Various techniques related to photovoltaic systems will now be described with reference to the drawings, wherein like reference numerals represent like elements throughout. In addition, as used herein, the term “exemplary” is intended to mean serving as an illustration or example and is not intended to indicate a preference.

  Referring now to FIG. 1, an exemplary solar panel 100 without any bypass diode is illustrated. In an exemplary embodiment, the solar panel 100 can be 1 meter to 2 meters long and 0.5 meters to 1.5 meters wide. Furthermore, although the solar panel 100 is configured to output 200 volts to 300 volts, in other embodiments, the solar panel 100 can be configured to output up to 2000 volts. According to a particular embodiment, the solar panel 100 can be configured to output 240 volts. However, as will be appreciated by those skilled in the art, the amount of voltage that can be output by the solar panel 100 may depend on the application in which the solar panel 100 is employed and may be above or below the range of 200-300 volts. .

  The solar panel 100 includes a plurality of photovoltaic submodules 102-148. Although the solar panel 100 is shown to include 24 photovoltaic submodules, the solar panel 100 can be used in applications where the solar panel 100 is employed, the amount of space available for mounting the solar panel 100, and solar. It should be understood that more or fewer photovoltaic submodules may be included depending on the arrangement of photovoltaic submodules 102-148 within panel 100.

  In the exemplary embodiment, photovoltaic sub-modules 102-148 can be electrically connected in parallel with each other. Thus, each of the photovoltaic submodules can output substantially the same voltage (eg, 200-600 volts). In another exemplary embodiment, the photovoltaic submodules 102-148 are not each electrically connected in parallel, but at least a subset of the photovoltaic submodules 102-148 are connected to the power management integrated circuit Such an integrated circuit outputs a desired voltage and / or current level resulting from power produced from a subset of photovoltaic sub-modules 102-148 electrically connected thereto. Can be configured as follows. For example, the solar panel 100 can include a single integrated circuit that is directly connected to each of the photovoltaic sub-modules 102-148. The power management integrated circuit can then be output by the solar panel 100 such that the final amount of power is at a predetermined desired level (voltage and current). In another exemplary arrangement, subsets of photovoltaic sub-modules can be coupled in parallel, and such subsets can be connected to a power management integrated circuit. For example, a first subset of photovoltaic sub-modules can include photovoltaic sub-modules 102, 104, 106, and 108 that can be electrically connected in parallel. Similarly, the second subset of photovoltaic sub-modules can include photovoltaic sub-modules 110, 112, 114, and 116 that can be electrically connected in parallel. The first subset of photovoltaic submodules and the second subset of photovoltaic submodules may then be connected to an integrated circuit that performs power management and causes the solar panel 100 to output a desired amount of power. Good. Other arrangements are also envisioned and are intended to be within the scope of the appended claims.

  At least some arrangements of photovoltaic sub-modules 102-148 in solar panel 100 in parallel can be used when one or more photovoltaic cells in the photovoltaic sub-module are operating in reverse breakdown. Effectively reduces the potential for damage to any of the submodules (or batteries therein). Since at least some of the photovoltaic submodules 102-148 are electrically arranged in parallel, when at least one of the photovoltaic submodules 102-148 is shielded, current matching between the modules is There is no need to occur. This effectively reduces the amount of power that can be dissipated across any one of the photovoltaic sub-modules, so that at least a portion of such sub-modules are shielded from light in the solar panel 100. Reduce the risk of damage to the photovoltaic submodule. Therefore, the solar panel 100 lacks a bypass diode.

  Referring now to FIG. 2, an exemplary photovoltaic submodule 200 that can be included within the solar panel 100 is illustrated. According to one embodiment, the size of the photovoltaic sub-module 200 can be 10 centimeters to 30 centimeters long and 10 centimeters to 30 centimeters wide. The photovoltaic sub-module 200 comprises a plurality of electrically connected photovoltaic cell groups 202-240, which are electrically connected in series. Although the photovoltaic submodule 200 is shown to include 20 groups, the number and arrangement of groups within the photovoltaic submodule 200 depends on the desired voltage output by the photovoltaic submodule 200. Please understand that you can. Furthermore, although the photovoltaic submodule 200 is shown to be a limited physical subelement of a solar panel, the photovoltaic submodule is defined by the circuitry employed to connect the cells in the solar panel. It should be understood that this can be done. Both arrangements are intended to be within the scope of the appended claims.

  According to one embodiment, the photovoltaic sub-module 200 can comprise about 100 groups, each of which is configured to output a consistent voltage, eg, about 2.4 volts. In such an embodiment, the desired output of the photovoltaic submodule 200 is about 240 volts. Further, as shown in the examples herein, some of the groups may be connected in parallel. For example, the photovoltaic sub-module 200 can comprise a first plurality of groups connected in series and a second plurality of groups connected in series, the first plurality of groups and the second plurality of groups. Are connected in parallel.

  In the foregoing embodiment, groups 202-240 are each configured to output approximately 2.4 volts. Even if a subset of groups 202-240 are shielded in photovoltaic submodule 200, the voltage output is thereby relatively low and the current passing through groups 202-240 is relatively low ( Therefore, even if individual cells in a group operate in reverse breakdown, it is not sufficient to damage such a group 202-240 (or the cells therein) Power is dissipated across groups 202-240. Thus, the photovoltaic submodule 200 need not include any bypass diodes connected to any of the groups 202-240.

Referring now to FIG. 3, an exemplary group 300 that may be included as one of the groups 202-240 within the photovoltaic submodule 200 is illustrated. Group 300 includes a plurality of photovoltaic cells 302-332. According to one embodiment, the photovoltaic cells 302-332 are constructed using a microfabrication concept and are relatively thin (1.0-50 micrometers thick) and small (50 micrometers to 10 millimeters on the side). ) Photocells can be microsystem compatible photovoltaic cells. In another example, the photovoltaic cell can be less than 2 centimeters long by 2 centimeters wide. For example, the following references, incorporated herein by reference, describe the construction of photovoltaic modules comprising a large number of photovoltaic cells using microfabrication techniques: Nielson, et al. , “Microscale C-SI (C) PV Cells for Low-Cost Power”, 34 ^th IEEE Photovoltaic Conference, June 7-10 2009, Philadelphia, PA, 978-1904, et al. . , “Microscale PV Cells for Concentrated PV Applications,” 24 ^th European Photovoltaic Solar Energy Conference, September 21-25, 2009, Hamburg 38, Hamburg 63, Hamburg 63, Hamburg 63, Hamburg 63 In summary, such references describe certain solar light collection systems with integrated micro-optic lenses, and with silicon (Si) and gallium arsenide (GaAs) with an efficiency of over 10%. A relatively thin battery fabricated using the epitaxial lift-off method is described therein.

  Thus, the photovoltaic cells 302-332 can be or include a Si cell, a GaAs cell, and / or an indium gallium phosphide (InGaP) cell. Thus, it should be understood that at least one of the photovoltaic cells 302-332 can be a III-V photovoltaic cell. Additionally or alternatively, the photovoltaic cells 302-332 can include at least one germanium (Ge) photovoltaic cell. Still further, the photovoltaic cells 302-332 can be or be included in a multi-junction cell that includes layers of different types of photovoltaic cells with different band gaps. Different battery types that integrate heterogeneously (eg, vertically stacked) with respect to the dielectric layers in between can provide high performance multi-junction batteries, and photovoltaic panel designers can achieve monolithic battery lattice matching and Freed from serial connection constraints.

  In the exemplary embodiment, each of the photovoltaic cells 302-332 can be a multi-junction cell, and the layers are connected together for each multi-junction cell. This effectively creates a string of photovoltaic cells that are electrically connected in series in a relatively small amount of space. In another exemplary embodiment, as shown herein, the batteries in a multi-junction battery may not be connected together. In yet another exemplary embodiment, the photovoltaic cells 302-332 can be of the same type (silicon). Other arrangements of photovoltaic cells are also envisioned.

  In the exemplary embodiment, the sub-module 300 may comprise a first photovoltaic string 334, a second photovoltaic string 336, a third photovoltaic string 338, and a fourth photovoltaic string 340. The first photovoltaic string 334 includes photovoltaic cells 302-308 that are electrically connected in series. Similarly, the second photovoltaic string 336 comprises photovoltaic cells 310-316 that are electrically connected in series. The third photovoltaic string 338 includes photovoltaic cells 318-324 that are electrically connected in series, and the fourth photovoltaic string 340 includes photovoltaic cells 326-332 that are electrically connected in series. The first photovoltaic string 334, the second photovoltaic string 336, the third photovoltaic string 338, and the fourth photovoltaic string 340 are electrically connected in parallel.

  As will be appreciated by those skilled in the art, different types of photovoltaic cells have different operating voltages. For example, if the photovoltaic cells 302-332 are Ge cells, the operating voltage may be about 0.3 volts. If the photovoltaic cells 302-332 are Si cells, the operating voltage may be about 0.6 volts. If the photovoltaic cells 302-332 are GaAs cells, the operating voltage may be about 0.9 volts, and if the photovoltaic cells 302-332 are InGaP cells, the operating voltage is about 1.3 volts. May be. According to one embodiment, the photovoltaic cells 302-332 can be Si cells. In such an embodiment, each of the photovoltaic strings 334-340 outputs an output of about 2.4 volts (common voltage), and thus the output of the group 300 is about 2.4 volts. In this case, strings 334, 336, 338, and 340 have different numbers of batteries for different battery types and approximate the common voltage. For example, in an exemplary embodiment, the first photovoltaic cell string 334 may include eight germanium cells (8 × 0.3 = 2.4), and the second photovoltaic cell string 336 includes four silicon cells. The third photovoltaic cell string 338 can include three GaAs cells (3 × 0.9 = 2.7), and the fourth photovoltaic cell's string 338 can include four cells (4 × 0.6 = 2.4). The string 340 can include two InGaP batteries (2 × 1.3 = 2.6). Slight voltage mismatch is acceptable and, if desired, a greater number of batteries and higher voltages can be used to provide a more precise voltage match. In another embodiment described above, the power management circuit can be used independently to boost the voltage generated by the series connection of different battery types to a common voltage. If the desired output of the solar panel 100 is approximately 240 volts, the photovoltaic sub-module 200 can include 100 groups 300 that are electrically connected in series. Thus, each sub-module 102-148 in the solar panel 100 outputs approximately 240 volts, and the output of the solar panel 100 is therefore approximately 240 volts.

  Using this embodiment, the solar panel 100 includes 38,400 batteries. When the entire solar panel 100 is illuminated, the photovoltaic cells 302-332 in each of the groups generate 4 milliwatts of power. For microsystem capable photovoltaic cells, about 100 milliwatts of power across a single cell will not be damaged even if such a cell is operating in reverse breakdown. Power above 100 milliwatts can occur across a single cell due to the selective arrangement of photovoltaic cells, submodules, and modules in a solar panel in series / parallel / series / parallel as described herein The nature is low. Given such an exemplary arrangement and the use of microsystem-compatible photovoltaic cells, solar panels comprised of the aforementioned photovoltaic cells are not susceptible to damage to individual cells even when a portion of the solar panel is shaded. It is readily apparent that any bypass diode can be eliminated.

  Referring now to FIG. 4, an exemplary photovoltaic submodule 400 that can be included as one of the photovoltaic submodules 102-148 within the solar panel 100 is illustrated. According to one embodiment, the photovoltaic sub-module 400 can comprise a plurality of multi-junction photovoltaic cells, such that each multi-junction photovoltaic cell comprises a plurality of photovoltaic cells. As described above, each multi-junction photovoltaic cell can comprise a Si photovoltaic cell and a III-V photovoltaic cell. In more specific examples, each multi-junction photovoltaic cell can comprise a Ge photovoltaic cell, a Si photovoltaic cell, a GaAs photovoltaic cell, and an InGaP photovoltaic cell.

  The exemplary photovoltaic sub-module 400 includes 72 multi-junction photovoltaic cells, each of which includes a Ge cell, a Si cell, a GaAs cell, and an InGaP cell. These different batteries are shown to be laid out adjacent to each other. However, such a layout is for illustrative purposes. As described above, the batteries in the multi-junction battery are stacked on top of each other. In another exemplary embodiment, the batteries can be installed in side-by-side configurations (eg, when spread spectrum optics are used).

  The photovoltaic module 400 comprises a different number of each battery type (creating a string) connected in series to reach a similar intermediate (higher) voltage. These strings are connected in parallel and can effectively add current. In one embodiment, the desired intermediate voltage output by photovoltaic module 400 can be about 10 volts. As described above, Ge cells may have an operating voltage of about 0.3 volts, Si cells may have an operating voltage of about 0.6 volts, and GaAs cells have an operating voltage of about 0. It may have an operating voltage of 9 volts, and the InGaP battery may have an operating voltage of about 1.3V. Thus, the photovoltaic sub-module 400 can comprise a first string of Ge cells 402 and a second string of Ge cells 404, each comprising 36 cells that are electrically connected in series. Therefore, the first string of the Ge battery 402 and the second string of the Ge battery 404 each output about 10.8V.

  The exemplary photovoltaic submodule 400 further comprises a first string of Si cells 406, a second string of Si cells 408, a third string of Si cells 410, and a fourth string of Si cells 412. Each string of Si cells 406-412 can comprise 18 cells electrically connected in series, resulting in each string outputting approximately 10.8 volts.

  The submodule 400 additionally includes a first string of GaAs batteries 414, a second string of GaAs batteries 416, a third string of GaAs batteries 418, a fourth string of GaAs batteries 420, and a fifth string of GaAs batteries 422. And a sixth string of GaAs batteries 424. Each string of GaAs batteries 414-424 may comprise twelve batteries electrically connected in series, resulting in each string of GaAs batteries outputting approximately 10.8 volts.

  Further, the sub-module 400 also includes a first string of InGaP batteries 426, a second string of InGaP batteries 428, a third string of InGaP batteries 430, a fourth string of InGaP batteries 432, and a fifth string of InGaP batteries 434. , A sixth string of InGaP battery 436, a seventh string of InGaP battery 438, an eighth string of InGaP battery 440, and a ninth string of InGaP battery 442. Each string of InGaP cells 426-442 can comprise eight cells electrically connected in series, resulting in each string of InGaP cells outputting approximately 10.4 volts.

  From the foregoing, it can be confirmed that the intermediate operating voltage of each string of batteries can be about 10 volts. Further, it can be ascertained that the voltages output by different battery type strings are not the same, so the voltage output by sub-module 400 will be the lowest voltage output by the battery string.

  Since only one type of battery is initially connected in series, the power output from other batteries in sub-module 400 will cause a decrease in the output of one type of battery versus another type of battery. It is relatively unaffected by the resulting spectral shift. For example, a 10% reduction in current from a battery type results in a 1-4% reduction in array current, depending on which battery's solar thermal input is reduced. Thus, the sub-module 400 suffers less output power reduction from spectral shifts that affect the cell type response in an unbalanced manner compared to conventional photovoltaic modules.

  Referring again to FIG. 1, the solar panel 100 is not shown, but the voltage output by the solar panel 100 from DC to AC at a stage desired by a consumer of power produced by such a solar panel 100. Can be associated with an inverter. Further, although not shown, the solar panel 100 can include micro-collecting optics configured to collect light from the sun onto a photovoltaic cell therein. In another exemplary embodiment, rather than performing precise voltage matching between battery types, the microelectronics will cause the intermediate voltage to reach the desired level (the voltage output by each of the modules 102-148). Can be adopted. Thus, the photovoltaic sub-modules or groups can include one or more DC / DC converters (with micro power tracking electronics) to allow the intermediate output voltage to be approximately equally and dynamically adjustable. . Further, the photovoltaic cell group can include a micro inverter that converts a DC voltage output by a battery or an array of batteries into an AC voltage. Since the individual batteries in the solar panel 100 are relatively small in size, there is sufficient space between the batteries, submodules, or groups to add various microelectronic devices for boost conversion and power tracking. Exists.

  Referring now to FIG. 5, a cut-away view of an exemplary heterogeneous (non-monolithic) integrated multi-junction photovoltaic cell 500 is illustrated. Multi-junction photovoltaic cell 500 comprises a plurality of photovoltaic cells, InGaP cell 508 initially receives light from the sun, GaAs cell 506 is immediately adjacent to InGaP cell 508, and Si cell 504 is a GaAs cell 506. The Ge battery 502 is immediately adjacent to the Si battery 504. It should be understood that other arrangements are contemplated by the inventors and are intended to be within the scope of the appended claims.

  An exemplary embodiment in which the solar panel 100 is beneficially employed is any facility where at least partial shadows are possible, such as the rooftop of a building near trees, an area that is intermittently covered by clouds, Includes areas close to air traffic, and the like. In addition, the features described herein are flexible in that the solar panel 100, a portion thereof, or the entire installation is in a manner such that at least a portion of the solar panel 100 is always shaded. Useful in equipment that is curved, fitted, or otherwise non-planar. In such an installation, the solar panel can output a desired voltage without the solar panel 100 including a bypass diode.

  Referring now to FIGS. 6-7, various exemplary methodologies are illustrated and described. Although a methodology is described as a sequence of actions performed in a sequence, it should be understood that a methodology is not limited by the sequence order. For example, some actions may occur in a different order than that described herein. In addition, the action may occur in parallel with another action. Further, in some cases, full action may not be required to implement the methodology described herein.

  Referring now to FIG. 6, an example methodology 600 that facilitates the creation of a solar panel without a bypass diode is illustrated. Methodology 600 begins at 602, where a plurality of microsystem capable photovoltaic cells are received. In an exemplary embodiment, the microsystem capable photovoltaic cell can have both positive and negative contacts on its backside.

  At 606, a plurality of microsystem-compatible photovoltaic cells can be electrically connected to create a photovoltaic submodule that does not have a bypass diode. As mentioned above, the relatively small amount of current traveling through the microsystem capable photovoltaic cell does not damage any individual photovoltaic cell, even when operating in reverse breakdown, when such a cell is shaded. Make sure.

  At 608, the plurality of photovoltaic submodules are electrically connected to create a solar panel. Since the photovoltaic sub-module consists of microsystem compatible photovoltaic cells, the solar panel can eliminate the bypass diode. However, the solar panel, in the exemplary embodiment, can be powered within the solar panel so that the power management integrated circuit can output power based at least in part on the voltage output by the individual photovoltaic sub-modules. A power management integrated circuit electrically connected to the photovoltaic submodule. In another embodiment, the power management integrated circuit is based on a voltage in which a string of photovoltaic cells is electrically connected to the power management integrated circuit and the output of the submodule is output by a separate group connected to the integrated circuit. As such, it can be installed in connection with the group. Methodology 600 is completed at 610.

  Referring now to FIG. 7, another exemplary methodology 700 for creating a solar panel that lacks a bypass diode is illustrated. Methodology 700 begins at 702 where a plurality of photovoltaic sub-modules are received.

  At 706, the photovoltaic sub-modules are electrically connected to produce a solar panel, at least a subset of the photovoltaic sub-modules are electrically connected in parallel, and the solar panel is free of bypass diodes. Methodology 700 is completed at 708.

  It should be noted that some examples have been provided for illustrative purposes. These examples should not be construed as limiting the appended claims. In addition, it should be appreciated that the examples provided herein may be rearranged and still fall under the scope of the claims.

Claims (13)

A photovoltaic sub-module that outputs 500 volts to 2000 volts ,
The photovoltaic sub-module comprises a plurality of microsystem-compatible photovoltaic cells that are electrically connected to each other via a positive and negative backside, and each microsystem-compatible photovoltaic cell in the plurality of microsystem-compatible photovoltaic cells is only 2 centimeters of the size of the height and width of two centimeters, the photovoltaic submodule, rather name any bypass diode,
The photovoltaic sub-module further comprises a first group, the first group comprising a first string of microsystem compatible photovoltaic cells and a second string of microsystem compatible photovoltaic cells, the microsystem compatible photovoltaic cells The cells in the first string are electrically connected in series, and the cells in the second string of the microsystem-compatible photovoltaic cells are electrically connected in series, the first string and the second Strings are electrically connected in parallel,
The photovoltaic sub-module further comprises a second group, the second group comprising a third string of microsystem-capable photovoltaic cells and a fourth string of microsystem-capable photovoltaic cells, the microsystem-capable photovoltaic cells The batteries in the third string are electrically connected in series, the batteries in the fourth string of the microsystem-compatible photovoltaic cells are electrically connected in series, and the third string and the fourth string are connected in series. The first group is electrically connected in series with the second group;
The series, parallel connection of the group, the string and the battery allows the maximum power that can occur across any microsystem capable photovoltaic cell in operation to be less than 100 milliwatts, even when the battery is in reverse breakdown. As is , the photovoltaic sub-modules are arranged .   The photovoltaic sub-module of claim 1 having a length of less than 30 centimeters and a width of less than 30 centimeters.   The photovoltaic submodule according to claim 1, wherein the plurality of microsystem-compatible batteries include at least one of an InGaP battery or an InGaAs battery.   The photovoltaic submodule of claim 1, wherein the plurality of microsystem-compatible batteries comprise GaAs batteries.   The photovoltaic submodule according to claim 1, wherein the plurality of microsystem-compatible batteries include at least one of a Ge battery and a Si battery.   The photovoltaic submodule according to claim 1, wherein each of the plurality of multi-junction batteries includes the plurality of photovoltaic cells.   The photovoltaic sub-module according to claim 1 constituted by a solar panel. The photovoltaic submodule of claim 7 , wherein the solar panel is free of any bypass diodes. The photovoltaic submodule of claim 8 , wherein the solar panel is non-planar. A solar panel, the solar panel
First and photovoltaic submodule according to claim 1,
A second photovoltaic sub-module according to claim 1 ;
With
The first photovoltaic sub-module and the second photovoltaic sub-module are electrically connected in parallel and the solar panel is a solar panel without any bypass diode. The solar panel of claim 10 , wherein the solar panel is configured to output 200 volts to 600 volts. The solar panel of claim 10 , wherein the first photovoltaic sub-module is less than 30 centimeters long and less than 30 centimeters high. The solar panel of claim 10 , wherein a plurality of multi-junction photovoltaic cells comprises a first string of the microsystem capable photovoltaic cells and a second string of the microsystem capable photovoltaic cells.