Solar cell array having changeable string length

Abstract

To provide a solar cell array including current flow path changing means for adapting to voltage change due to breakdown of the solar cell caused by radiation damage, and the like.SOLUTION: In a solar cell array consisting of one or more than one solar cells 14 attached to a substrate, the substrate includes one or more than one electrical connections 20 with the solar cells 14, and one or more than one switches 54 for changing the string length for one or more than one solar cells 14, by changing the current flow path between one or more than one solar cells 14 and one or more than one electrical connections 20.SELECTED DRAWING: Figure 15

Description

Field of the Technology

[0001] This disclosure generally relates to solar cell panels, and more specifically to solar cell arrays having a variable string length.

Background Art

[0002] A typical spaceflight-capable solar cell panel assembly involves constructing a solar cell array consisting of long strings of solar cells. These strings can have a variable length, i.e., the number of solar cells, and can be made very long.

[0003] Conventional solar cell arrays are constructed with a fixed number of solar cells to generate the required output voltage. The fixed number of solar cells has to be sized under the most difficult conditions, which is the hottest operating period including the maximum dose of electrons and protons. In particular, with existing solutions, strings sized for the worst-case environment are produced.

[0004] For 100V operation, this can be up to 55 solar cells. At the start of operation of the solar cell array, radiation damage is minimal and it may be possible to reach 100V with up to 45 solar cells. Thus, at the start of operation, approximately 18% (10 / 55) of the solar cells are not generating usable power.

[0005] This will change with the operating temperature and the cumulative dose of high-energy electrons and protons in the space environment. Most importantly, it is the voltage that changes during the life of the solar cell array.

[0006] Therefore, what is needed is a means to adapt to changes in the operation of the solar cell array during its life.

Summary of the Invention

[0007] To overcome the limitations described above and any other limitations that may become apparent from reading and understanding this specification, the present disclosure describes a solar cell array comprising one or more solar cells mounted on a substrate, wherein the substrate includes one or more electrical connections to the solar cells, and the substrate includes one or more switches for changing the string length of one or more of the solar cells by changing the current path between one or more of the solar cells and one or more of the electrical connections.

[0008] When at least one of the solar cells having one or more trimmed corners is mounted on a substrate, an area of ​​the substrate remains exposed, and this exposed area of ​​the substrate includes at least one of the switches. At least one of the solar cells is mounted on the substrate such that a corner region defined by the trimmed corner of at least one adjacent solar cell is aligned, thereby exposing an area of ​​the substrate. At least one of the switches is located within a corner region defined by the trimmed corner adjacent to at least one of the solar cells.

[0009] The switch changes the string length of one or more of the solar cells in response to a control signal, and the switch changes the string length to allow for series connection between multiple strings and reconfiguration of the output. The switch is a single-pole single-throw (SPST) switch or a dual-pole single-throw (DPST) switch.

[0010] The substrate includes one or more traces connected to a switch for making electrical connections between solar cells.

[0011] Here, we refer to the drawings, and throughout each drawing, similar reference numbers represent the corresponding parts. [Brief explanation of the drawing]

[0012] [Figure 1] This shows the conventional structure of a solar cell panel. [Figure 2] This shows the conventional structure of a solar cell panel. [Figure 3] A and B show an improved structure of a solar cell panel as an example. [Figure 4] A and B illustrate an alternative structure for a solar cell panel as an example. [Figure 5] Figures 3 and 4 show the front view of an exemplary solar cell that may be used in the improved solar cell panel. [Figure 6] Figure 5 shows the back of an exemplary solar cell. [Figure 7] An example shows cells arranged within a two-dimensional (2D) grid of an array. [Figure 8] This shows an example of an array in which one or more bypass diodes are added to an exposed area of ​​the substrate within a corner region. [Figure 9] This example shows a bypass diode mounted on the back of the cell, with the interconnector or contact for the bypass diode extending into the corner region between the front and rear contacts. [Figure 10] Figure 9 shows a front view of an example where the interconnector or contact for the bypass diode extends into the corner region between the front and rear contacts. [Figure 11] Figures 9 and 10 show cells arranged in a 2D grid array and mounted on a substrate, wherein bypass diodes are mounted on the back of the cell and the contacts for the bypass diodes extend into the corner region of the cell. [Figure 12] This example shows an upward / downward series connection between cells in an array. [Figure 13] Shows the left / right series connection between cells of an array according to one embodiment. [Figure 14] A shows an open switch, and B, C, and D show three different configurations with one, two, and one switches closed, respectively. [Figure 15] Shows a corner connection layout with single-pole single-throw (SPST) switches. [Figure 16] Shows the implementation of switches for changing the length of a string of solar cells. [Figure 17] Figure 17 is a layout showing a method of joining short segments of solar cells into a longer string. [Figure 18] Shows the switching of solar cells for changing the length of a string. [Figure 19] Shows a reconfigurable array of solar cells. [Figure 20] A shows a method in which multiple partial strings are joined together to provide the required string length and output voltage, and B shows a group of solar cells each divided into two parts, and one part from each group of solar cells is joined together to provide the required string length. [Figure 21] Shows a layout of a reconfigurable solar cell consisting of three flexible sheets each having two parts. [Figure 22] Shows how switches can be used to reconfigure the solar cells of Figure 21. [Figure 23] Explains a method of manufacturing a solar cell, a solar cell panel, and / or a satellite according to one example. [Figure 24] One example shows a satellite resulting from having a solar cell panel made up of solar cells. [Figure 25] This is a diagram of a solar cell panel in the form of a functional block diagram, as an example. [Figure 26] A through E show experimental results in which a solar cell array using a flexible circuit board, based on a corner conductor design, was constructed to demonstrate the reconfiguration of the array's string length. [Modes for carrying out the invention]

[0013] The following description refers to the accompanying drawings that form part of this application, which are illustrated for the purpose of illustrating specific examples in which the disclosure may be carried out. It should be understood that other embodiments are also available and that structural modifications may be made without departing from the scope of the disclosure.

[0014] For example, a new approach to designing solar cell arrays used for powering spaceflight is based on the electrical connections between solar cells within the array.

[0015] These new techniques rearrange the components of solar cells and the arrangement of solar cells within an array. Instead of connecting solar cells to form long, straight strings and then assembling them on a substrate, the solar cells are mounted individually to the substrate, and areas of the substrate are exposed so that the corner regions of adjacent cells are aligned on the substrate. Electrical connections between cells are made by corner conductors formed on or within these corner regions on the substrate. As a result, this technique presents a design for solar cell arrays based on individual cells.

[0016] Thus, a single laydown process and layout can be used for manufacturing solar cell arrays. The flow of current between solar cells is assisted by conductors embedded in the substrate. These electrical connections define specific characteristics of the solar cell array, such as its dimensions, stay-out areas, and circuit terminations. This method simplifies manufacturing, enables automation, and reduces costs and transport times.

[0017] Figures 1 and 2 show a conventional structure of a solar cell panel 10, including a substrate 12, multiple solar cells 14 arranged in an array, and electrical connectors 16 between the solar cells 14. Figure 1 shows a half-size solar cell 14, and Figure 2 shows a full-size solar cell 14. Space-grade solar cells 14 are made from circular germanium (Ge) substrate starting material. To mount them on the solar cell panel 10 at a higher density, these are later processed into a semi-rectangular shape. This wafer is often die-cut into one or two solar cells 14, which are described here as half-size or full-size solar cells 14. Electrical connectors 16 that electrically connect the solar cells 14 are made along the long, parallel ends between the solar cells 14. The strings of solar cells 14 are constructed to have any number of solar cells 14 in length, so these series connections (of cells) are completed before they are mounted on the substrate. The strings of solar cells 14 are then placed on the substrate 12 and mounted.

[0018] In Figure 2, wiring 18 is attached to the end of a string of solar cells 14, either to electrically connect the string to another string, or to terminate the wiring to form a circuit and interrupt the current in the array of solar cells 14. Connections between strings and circuit terminations are usually made on the substrate 12, and typically using wiring 18. However, some solar cell panels 10 use printed circuit board (PCB) type materials with embedded conductors.

[0019] Adjacent strings of connected solar cells 14 can extend in parallel or antiparallel directions. In addition, strings of connected solar cells 14 may or may not be aligned. Many factors compete with each other in the layout of the solar cells 14, resulting in regions where the solar cells 14 are parallel or antiparallel, and regions where they are aligned or not aligned.

[0020] Figures 3A and 3B show an improved apparatus and structure of the solar cell panel 10a according to one embodiment, with Figure 3B being a detailed enlargement of the area within the dashed circle in Figure 3A. Figures 5 to 13 show and describe in more detail the various components of the solar cell panel 10a.

[0021] The solar cell panel 10a includes a substrate 12 for solar cells 14, having one or more corner conductors 20 on top. In one embodiment, the substrate 12 is a multilayer substrate 12 consisting of one or more Kapton® (polyimide) layers separating one or more patterned metal layers. The substrate 12 may be mounted on a substrate 10a with high rigidity, similar to a conventional assembly. Alternatively, the substrate 12 may be mounted on a lighter and thinner frame or panel 10a for mounting or deployment.

[0022] Multiple solar cells 14 are mounted on the substrate 12 in a two-dimensional (2-D) grid pattern in the array 22. In this embodiment, the array 22 consists of 96 solar cells 14 arranged in 4 rows x 24 columns, but it is acknowledged that in different embodiments, any number of solar cells 14 may be used.

[0023] The solar cell 14 has trimmed corner portions 24 that define a corner region 26, as indicated by the dashed circle. The solar cell 14 is mounted on the substrate 12 such that the corner regions 26 of adjacent solar cells 14 are aligned, thereby exposing an area 28 of the substrate 12. The exposed area 28 of the substrate 12 includes one or more corner conductors 20, and one or more electrical connections are made between the solar cell 14 and the corner conductors 20 within the corner region 26 formed by the trimmed corner portions 24 of the solar cell 14.

[0024] In this embodiment, the corner conductor 20 is a conductive path that is attached to, printed on, embedded in, or deposited on the substrate 12 before and / or after the solar cells 14 are attached to the substrate 12, facilitating connections between adjacent solar cells 14. The connection between the solar cells 14 and the corner conductor 20 is made after the solar cells 14 are attached to the substrate 12.

[0025] In one embodiment, four adjacent solar cells 14 are aligned on a substrate 12, and four trimmed corner portions 24, one from each solar cell 14, are gathered together in a corner region 26. Next, the solar cells 14 are individually mounted on the substrate 12. At this time, the solar cells 14 are placed on a corner conductor 20, and an electrical connection is made between the solar cells 14 and the corner conductor 20.

[0026] The solar cell 14 may be mounted on the substrate 12 as a CIC (cell, interconnect, cover glass) unit. Alternatively, the uncovered solar cell 14 may be assembled on the substrate 12, then the interconnect may be attached to the solar cell 14, followed by a cover glass for a single solar cell 14, a cover glass for a multi-cell solar cell 14, a polymer cover sheet for a multi-cell solar cell 14, or a spray sealant. This assembly protects the solar cell 14 from damage that would limit its performance.

[0027] Figures 4A and 4B show an alternative structure of the solar cell panel 10a in one example, with Figure 4B being a detailed enlargement of the area within the dashed circle in Figure 4A. In this embodiment, only a small number of corner conductors 20 are printed on or incorporated into the substrate 12. Instead, most of the corner conductors 20 are contained within a power routing module (PRM) 30 mounted on the substrate 12.

[0028] Figure 5 shows the front view of an exemplary solar cell 14 that may be used in the improved solar cell panel 10a of Figures 3A-B and 4A-B. The solar cell 14, which is a CIC unit, is a half-size solar cell 14. (A full-size solar cell 14 may also be used.)

[0029] As shown by the dashed circle, the solar cell 14 is manufactured to have at least one trimmed corner portion 24 defining a corner region 26, the corner region 26 formed by the trimmed corner portion 24, and includes at least one contact 32, 34 that makes an electrical connection with the solar cell 14. In the embodiment shown in Figure 5, the solar cell 14 has two trimmed corner portions 24, each having a front contact 32 on the front of the solar cell 14 and a rear contact 34 on the back of the solar cell 14, with the contacts 32 and 34 extending into the corner region 26. (A full-size solar cell 14 has four trimmed corner portions 24, each having one front contact 32 and one rear contact 34.)

[0030] The presence of trimmed corners 24 often leads to the use of circular wafers as the starting material for solar cells 14. In conventional panels 10, after the solar cells 14 are mounted on the substrate 12, these trimmed corners 24 become unused space on the panel 10. However, the new method described herein utilizes this unused space. Specifically, metal foil interconnects, which include corner conductors 20, front contacts 32, and back contacts 34, are moved to the corner region 26. In contrast, in existing CICs, the interconnects are mounted on the front of the solar cells 14 and connected to the back (where the connection occurs) during string fabrication.

[0031] The current generated by the solar cell 14 is collected at the front of the solar cell 14 by a grid 36 of thin metal fingers 38 and wider metal busbars 40, which are connected to both front contacts 32. There is a balance between adding metal to the grid 36 to reduce the amount of light entering the solar cell 14 and thus reducing the output of the solar cell 14, and the fact that the increased metal reduces resistance. The busbars 40 are low-resistance conductors that carry large currents and also provide redundancy in case the front contacts 32 are disconnected. Generally, for optimization, short busbars 40 extending directly between the front contacts 32 are required. By having the front contacts 32 within the trimmed corners 24, the busbars 40 are moved away from the outer circumference of the solar cell 14. This is achieved while simultaneously minimizing the length of the busbars 40 and thus minimizing light shielding. In addition, this also shortens the fingers 38. This reduces the parasitic resistance within the grid 36 because the shorter length of the fingers 38 reduces the total amount of current carried. This leads to a design that moves the front contact 32 and the connecting busbar 40 in order to provide shorter, thinner fingers 38.

[0032] Figure 6 shows the back surface of the solar cell 14 illustrated in Figure 5. The back surface of the solar cell 14 has a metal back layer 42 that is connected to both back contacts 34.

[0033] Figure 7 shows a 2D grid of solar cells 14 arranged in an array 22 according to one embodiment. The array 22 comprises multiple solar cells 14 mounted on a substrate 12 such that the corner regions 26 of adjacent solar cells 14 are aligned, thereby exposing an area 28 of the substrate 12. Electrical connections (not shown) between the solar cells 14 are made within the exposed area 28 of the substrate 12 using front contacts 32 and rear contacts 34 of the solar cells 14, as well as corner conductors 20 (not shown) formed on or within the exposed area 28 of the substrate 12.

[0034] During assembly, the solar cells 14 are individually attached to the substrate 12. This assembly can be performed directly on the support surface, i.e., the substrate 12, which can be either rigid or flexible. Alternatively, the solar cells 14 could be assembled in a 2D grid pattern on a temporary support surface and then transferred to the final support surface, i.e., the substrate 12.

[0035] Figure 8 shows one embodiment of the array 22, in which one or more bypass diodes 44 are added to an exposed area 28 within a corner region 26 of the substrate 12 for use in one or more electrical connections. The bypass diodes 44 protect the solar cells 14 in the event that they are unable to generate current, which could be due to partial shading, in which case the solar cells 14 are reverse-biased. In one embodiment, the bypass diodes 44 are mounted on the substrate 12 in the corner region 26 independently of the solar cells 14.

[0036] Figure 9 shows one embodiment in which a bypass diode 44 is attached to the back of the solar cell 14, an interconnector or contact 46 for the bypass diode 44 is connected to the back layer 42, and further extends within a corner region 26 between the front contact 32 and the back contact 34.

[0037] Figure 10 shows a front view of the embodiment of Figure 9, in which an interconnector or contact 46 for a bypass diode 44 (not shown) extends within a corner region 26 between the front contact 32 and the rear contact 34.

[0038] Figure 11 shows the solar cells 14 from Figures 9 and 10, which are arranged in a 2D grid pattern on the array 22 and attached to the substrate 12. In this case, a bypass diode 44 (not shown) is attached to the back of the solar cell 14, and a contact 46 for the bypass diode 44 extends into the corner region 26 of the solar cell 14.

[0039] One advantage of this method is that the layouts shown in Figures 7, 8, and 11 are generalized layouts. In particular, these layouts can be repeated over any dimensions desired by the customer of panel 10a. This greatly simplifies the assembly, modification, testing, and inspection processes.

[0040] The arrangement of the solar cells 14 and bypass diodes 44 is typical. Electrically connecting the solar cells 14 in series and terminating the string are important customizations for the end customer and are done separately from the layout. Within the corner area 26 of the solar cell 14, the front contacts 32 and rear contacts 34 must be connected. This can be done in numerous combinations to route the current along the desired path.

[0041] A connection is made between the solar cell 14 and the corner conductor 20. The front contacts 32 and rear settings 34 of the solar cell 14 are located in each corner region 26 for mounting to the corner conductor 20. The interconnectors for the front contacts 32 and rear contacts 34 of each solar cell 14 are welded, soldered, or otherwise joined to the corner conductor 20 to provide conductive paths 20, 32, and 34 for routing current to the outside of the solar cell 14.

[0042] The corner conductors 20 allow for arbitrary customization of electrical connections. Adjacent solar cells 14 can be electrically connected to direct current upward / downward or left / right according to specific design requirements. Current can also be routed to bypass stay-out areas as needed. The length and width of the solar cell array 22 can be set as desired. Furthermore, the width of the array 22 can vary depending on its length.

[0043] In one embodiment, the electrical connection is a series connection that determines the flow of current through multiple solar cells 14. This can be achieved by the connection scheme shown in Figures 12 and 13, where Figure 12 shows an upward / downward series connection 48 between solar cells 14 in an array 22, and Figure 13 shows a leftward / rightward series connection 50 between solar cells 14 in an array 22. In both Figures 12 and 13, these series connections 48, 50 are electrical connections between the front contacts 32 and rear contacts 34 of the solar cells 14 and the bypass diodes 44, and these series connections are made using corner conductors 20 formed on or within an exposed area 28 of the substrate 12. These series connections 48, 50 determine the flow of current (power) through the solar cells 14, as indicated by the arrow 52.

[0044] The corner conductors 20 between the solar cells 14 can take various forms. The corner conductors 20 can be completed using wires having electrical connections made at both ends by methods such as soldering, welding, conductive adhesive, or other processes. In addition to wires, metal foil connectors similar to interconnectors can also be applied. Metal conductor paths or traces (not shown) can also be incorporated into the substrate 12.

[0045] In short, this new method involves individually mounting solar cells 14 to a substrate 12 such that the corner regions 26 of two, three, or four adjacent solar cells 14 are aligned on the substrate 12. The solar cells 14 can be laid out such that the trimmed corner portions 24 are aligned so that the corner regions 26 are adjacent to each other, thereby exposing an area 28 on the substrate 12. Electrical connections between the solar cells 14 are made within these corner regions 26 between the front contacts 32 and rear contacts 32 of the solar cells 14, the bypass diodes 44, and the corner conductors 20 on or within the exposed area 28 on the substrate 12. These conductive paths are used to create strings of solar cells 14 in series connections 48, 50, which include circuits.

[0046] Solar cell array with adjustable string length The satellite power system requires power generated at a specific voltage produced by multiple series-connected solar cells 14. The voltage produced by each solar cell 14 varies primarily depending on the operating temperature, as well as the electron and proton irradiation history. This string is typically a fixed-length string of solar cells 14, designed to have enough solar cells 14 to reach the required voltage during operation. For much of the mission, the string generates more voltage than necessary. Effectively, one or more solar cells 14 do not contribute to the power. This disclosure describes a method for reconfiguring the string length during operation so that power can be collected from each solar cell 14 throughout the mission. This results in the ability to create a string that operates at a constant total output voltage and generates higher power from the solar cell array 22.

[0047] Conventional triple-junction solar cells 14 generate a maximum power of approximately 1.2A and 2.22V. This will vary with operating temperature and the cumulative dose of high-energy electrons and protons in the space environment.

[0048] Most importantly, the voltage changes. Power systems often collect current at a specific voltage known as the load voltage. From the start of life (BOL) to the end of life (EOL) of a satellite, the voltage can drop from 2.2V to 1.8V. To reach a load voltage that can be between 20V and 100V, many solar cells 14 are connected in series, with each solar cell 14 contributing to the string's voltage.

[0049] In one example, 45 solar cells 14 may be required to have a maximum power point close to 100V at BOL. On the other hand, at EOL, 55 solar cells 14 may be required to have a maximum power point of 100V. Therefore, the additional 10 solar cells 14 at BOL do not contribute to any power.

[0050] By implementing switches in the solar cell array 22, the string length can be reconfigured during operation. Specifically, the solar cell array 22 is reconfigured to have a string length that produces a maximum power point close to the load voltage.

[0051] For example, a solar cell array 22 having 990 solar cells 14 can be divided into many strings to supply power to a 100V power system. To supply power at 100V at end-of-life (EOL), the solar cell array 22 would have 18 strings with a maximum power point of 100V, with each of the 55 solar cells 14 requiring a long string. The power output would be 18 × 100V × 1.2A = 2160W. A conventional solar cell array with a fixed string length would supply this power at both end-of-life (BOL) and EOL. Irradiation may cause some variation in current and fill factor, but that is a secondary factor in this discussion.

[0052] Reconfiguring the string length would provide a much higher power level in BOL. In BOL, the solar cell array 22 could be reconfigured to generate a maximum power point of 100V using 22 strings, each having a length of 45 solar cells 14. The power output would be 22 × 100V × 1.2A = 2640W. This is 22% more power than in the previous example. The solar cell array 22 can be reconfigured during missions to change the string length from 45 to 55 solar cells 14. This would maintain the voltage at the maximum power point close to the 100V load voltage, providing optimal power.

[0053] The reconfigurable array 22 can also be advantageous in interplanetary missions where radiation and operating temperature change significantly, thereby altering the voltage of the solar cells 14.

[0054] In other applications, the load voltage may vary. For example, in the initial stages of operation, a satellite may move into its orbit using electric propulsion. The electric propulsion system may prefer a higher load voltage compared to operation in other stages of the mission. Reconfigurability could be implemented to change the string length, allowing the string's maximum power point to be changed to 160V, 200V, or 300V for electric propulsion and 100V for other stages of the mission.

[0055] Reconfigurability requires the introduction of several switches into the solar cell array 22. Wiring these switches into a conventional solar cell array would require inserting end tabs between the solar cells and wiring and the switches. Additionally, the switches would need signal wires to communicate the desired state (open or closed). This would involve significant effort, cost, and panel space. Furthermore, the extra connections would increase the risk of problems developing. These costs and risks outweigh the benefits, hindering the construction of a reconfigurable array.

[0056] However, in solar cell arrays 22 using a corner conductor layout 20, the cost of implementing a reconfigurable array 22 changes dramatically.

[0057] Figures 14A, 14B, 14C, and 14D show switches 54 used to change the current path between the solar cell 14 and the electrical connection. In these figures, the switches 54 are single-pole single-throw (SPST) switches 54 packaged together in pairs, but other switches 54 may be used, and the switches 54 may be sold individually, in pairs, or packaged as needed.

[0058] Each of the pair of SPST switches 54 may be controlled independently or together using one or more control signals (not shown). Figure 14A shows a pair of SPST switches 54 both open, Figure 14B shows a pair of SPST switches 54 with the left side open and the right side closed, Figure 14C shows a pair of SPST switches 54 both closed, and Figure 14D shows a pair of SPST switches 54 with the left side closed and the right side open.

[0059] Figure 15 shows a layout in which the switches 54 are located within a corner region 26. A pair of SPST switches 54 located in the upper center of the corner region 26 connect the rear contact 34 of the upper left solar cell 14 to either the string output line 56 or a series connection to the bypass diode 44, and to the next solar cell 14 in the lower left. The photocurrent flows from the rear contact 34 of the upper left solar cell 14 to the front contact 32 of the lower left solar cell 14. A pair of SPST switches 54 on the left side of the corner region 26 allows the front contact 32 of the lower left solar cell 14 to be connected in series with the rear contact 34 of the upper left solar cell 14, and allows the front contact 32 of the lower left solar cell 14 to be connected to the string output line 56.

[0060] These switches 54 allow the solar cell 14 to have a series connection to another solar cell 14 or to terminate to an embedded V+ or V-string output line 56. Furthermore, the switches 54 allow the solar cell 14 to be terminated through multiple connection paths. Similarly, the switches 54 may also have several connection paths, all of which follow the logic described herein.

[0061] The connections between the solar cells 14 on the right side of corner region 26 are a 180-degree mirror image of the connections between the solar cells 14 on the left side of corner region 26. However, the configuration of the left SPST switch 54 is reversed. On this left side, current flows from the rear contact 34 of the lower right solar cell 14 to the embedded V+ string output line 56 at the string endpoint. The front contact 32 of the upper right solar cell 14 is connected to the V- string output line 56.

[0062] The electrical connections made in the corner region 26 utilize the common layout of the solar cells 14, whether they are series connections or have circuit outputs. Busbars or wiring are unnecessary, saving labor and panel 10a area. Furthermore, the layout of the electrical connections in the corner region 26 takes advantage of the ability of the substrate 12 to include patterned wiring. The wiring layout of the substrate 12, which is more or less complex, has little to no cost increase. Any additional wiring required by the switch 54 is easily constructed with minimal additional effort. This combination of characteristics is ideally suited to a reconfigurable solar cell array 22.

[0063] A pair of SPST switches 54 may operate such that one SPST switch 54 is closed when the other SPST switch 54 is open, which could be done using a two-pole single-throw (DPST) switch 54. Furthermore, a pair of SPST switches 54 or DPST switches 54 could be implemented with one or more control signals. These SPST switches or DPST switches 54 could be electromechanical relays or micro-electromechanical system (MEMS) relays in which a solid conductor is mechanically bent to form a conductive path and then broken. Field-effect transistor devices are another available switch 54 constructed from silicon (Si), silicon carbide (SiC), or gallium nitride (GaN).

[0064] Figure 16 shows a group 58 of solar cells 14 labeled 1 through 15. This group 58 can be divided into two strings. Between the solar cell 14 labeled 11 and the solar cell 14 labeled 15, there are eight switches 54 in series that control the length of each of the two strings, and a ninth switch 54 is coupled between the solar cell 14 labeled 15 and outputs V1+ and V2+. The switches 54 can create the length of the first string between solar cells 11 through 15 and the length of the second string between solar cells 0 through 4. There are four fixed output lines, with the outputs of the first string being V1- and V1+, and the outputs of the second string being V2- and V2+.

[0065] V1- is always set from the beginning of the string before the solar cell 14 labeled 1. V1+ is at any point between the solar cell 14 labeled 11 and the solar cell 14 labeled 15, and may be the configuration at the end of life (EOL) when the voltage of the solar cell 14 drops. As depicted, V1+ terminates after the solar cell 14 labeled 13, and V2+ always terminates after the solar cell 14 labeled 15. As depicted, V2- terminates before the solar cell 14 labeled 14.

[0066] This solar cell array 22 allows the first string to be reconfigured to optimize the operating voltage by having the required string length. The second string will have a lower voltage output. Multiple copies of the second string using other groups 58 may need to be connected in series to reach the load voltage.

[0067] Figure 17 is a layout showing how strings are combined for a desired voltage output, and shows 14 groups 58 of solar cells 14. Each group 58 consists of solar cells 14 and switches 54 as shown in Figure 16. The first string of solar cells 14 in each group 58 generates the desired voltage from 11 to 15 solar cells 14 connected to outputs V1, V2, ..., V14. The second string of solar cells 14 in each group 58 generates the desired voltage from 0 to 4 solar cells 14 connected to outputs Va, Vb, ..., Vn.

[0068] The layout in Figure 17 shows two stages of group 58, with an additional switch 54 between the stages for connecting the second string from each of the groups 58. In this example, the string output Va- terminates directly to V15-. Va+ is connected to Vb- via two pairs of switches 54. The same thing happens between Vb+ and Vc- and continues across group 58. As shown, the switches 54 enable a series connection from Va to Vg. In this example, the first string of each group 58 is the length of 13 solar cells 14, and the second string is the length of 2 solar cells 14. The combination of segments that output Va to Vg is the length of 14 solar cells 14 in the string. These are the lengths of 14 solar cells 14 and are combined for the output V15, which generates a voltage sufficient to be utilized by the system.

[0069] Between Vg+ and Vh-, the output is terminated by switch 54a. These termination switches 54a indicate a change in the state of the switch element 54. The termination switches 54 terminate Vg+ to V15+ and Vh- to V16-. Next, Vh to Vn are connected in series to create another string of 14 solar cells 14. Vn+ is connected to V16+.

[0070] As a result, Figure 16 shows how a group 58 of solar cells 14 can be reconfigured with a long first string having a desired voltage output and a short second string that is a portion of the desired voltage, while Figure 17 shows how these short second strings can be combined to generate a desired voltage.

[0071] The length and layout of the strings can be changed as needed. This disclosure focuses on switching topologies. Implementing this wiring and switching on conventional solar cell arrays would require significant manual effort. The solar cell array 22 of this disclosure has embedded traces patterned within the substrate 12, allowing for the accommodation of complex wiring with minimal overhead and achieving the complexity of a reconfigurable solar cell array 22.

[0072] There are many configurations in which the string length can be changed by switching the solar cells 14. Figure 16 shows a group 58 consisting of 15 solar cells 14, where the string length can be changed by a single solar cell 14. It may be advantageous to switch a particular group 58 of solar cells 14.

[0073] Figure 18 shows one such combination. Figure 18 shows a solar cell array 22 having 24 solar cells 14 arranged in 4 rows and 6 columns. The solar cells 14 are labeled 1 to 24 and are connected in series by wires 60 along the sides (and tops) of the solar cells 14.

[0074] There are also traces 62 extending to the left and right of the flexible circuit board 12. These traces 62 are embedded beneath the solar cells 14, electrically isolated from the solar cells 14, and intended for string termination outputs. The traces 62 are accessible in the corner regions 26 between the solar cells 14, allowing any solar cell 14 to easily access the output lines 56.

[0075] Two of the embedded traces 62 are labeled A and B. These traces 62 will be accessible by solar cells 14 labeled 3, 4, 5, 6, 11, 12, 13, 14, 19, 20, 21, and 22. This is a typical configuration described for a solar cell array 22 consisting of solar cells 14 connected to a corner region 26. This is beneficial for a reconfigurable solar cell array 22.

[0076] Figure 19 shows how this can be used in a reconfigurable solar cell array 22. Here, the 24 solar cells 14 are shown smaller, providing more space to draw the wiring and switching connections. The shown geometry is well suited to the use of electrical connections in corner areas 26. Between the solar cells 14 labeled 11-12, 13-14, 19-20, 21-22 and the solar cell 14 labeled 24, there are switches 54 similar to those in Figure 16. These switches 54 could be implemented in corner areas 26, as shown in Figure 15, located between solar cells 14 in the same column position. As shown in Figure 16, there are two string outputs, namely V1 for the first string and V2 for the second string. V2- and V1+ are accessed by each switch 54. To enable this switching, only a single trace 62 for V1+ and V2- running under the solar cell 14 is required.

[0077] Traces 64 are deposited on the surface of the substrate 12, and traces 62 for V1+ and V2- are embedded so as to pass beneath the surface traces 64. Vertical composite lines 66 indicate an interconnector connecting a switch 54 to the embedded traces 62, and the switch 54 is configured such that the first string is the length of 13 solar cells 14 and the second string is the length of 11 solar cells 14.

[0078] A V1 string can have a length of 11, 13, 19, 21, or 24 solar cells 14. This is achieved by buried traces 62 running between the solar cells 14 of stages 3 and 4. These connections to output lines could be moved up the stages so that they are between the solar cells of stages 2 and 3. This would result in string lengths of 10, 14, 18, 22, or 24. These different combinations result from a four-stage solar cell array 22, with the output lines running between two stages. Additional output lines could be added between other stages to allow for more switching points and greater control over string length. However, this complexity would require traversing the buried traces 62 and necessitate additional effort.

[0079] This layout is easy to manufacture because the traces do not intersect each other on the same layer; that is, there are no intersecting solid or dashed traces. If these traces intersect, another metal layer and vias would be required, raising concerns about lifespan in the space environment. This configuration, in which the corner-connected solar cell array 22 has embedded traces 62 within the substrate 12, allows for a very simple connection path.

[0080] The configurations in Figures 16 and 17 were based on a group 58 of solar cells 14 divided into a first string of full voltage and a second string of partial voltage. The second strings of group 58 were then connected together to construct the required voltage.

[0081] Related techniques are shown in Figures 20A and 20B. Figure 20A includes multiple groups 58 of solar cells 14, each having the same configuration as shown in Figures 16 and 17. Each group 58 includes first and second strings 68a and 68b, where the first string 68a is a full-voltage string and the second string 68b is a partial-voltage string, and multiple partial-voltage second strings 68b across multiple groups 58 are connected together to supply the required string length and output voltage.

[0082] Figure 20B shows that each group 58 is divided into two strings 68a and 68b of different lengths, and the first and second strings 68a and 68b from each group 58 are connected together to provide the required string length. Specifically, the first string 68a of the first group 58 is a full-voltage string, the second string 68b of the first group 58 is a partial-voltage string combined with the first string 68a of the second group 58 to produce a full-voltage string, the second string 68b of the second group 58 is a partial-voltage string combined with the first string 68a of the third group 58 to form a full-voltage string, and the second string 68b of the third group 58 is a full-voltage string.

[0083] Although the example shown has only two strings 68a and 68b, these groups 58 could contain a larger or smaller number of strings. Specifically, group 58 could consist of full-voltage strings such as 1, 2, 3, 4, etc., and partial-voltage strings of 0, 1, or possibly multiple.

[0084] Figures 16–20 focus on reconfiguration by changing the string length with a small number of solar cells 14 to control the output voltage. This is beneficial because the voltage of individual solar cells 14 will change during the mission due to exposure to cosmic radiation and changes in operating temperature.

[0085] Figures 21 and 22 illustrate the application of reconfigurability to larger variations in string length. This would be suitable for applications where large variations in output voltage are desired.

[0086] For example, during satellite operation, the solar cell array 22 is generally charging a set of batteries, and the load voltage may be 100V or less. However, during the mission phase, the satellite uses electric propulsion to change its orbital position, and the load voltage may be 160V, 200V, 300V, or other. It may be desirable for the solar cell array 22 to output a desired voltage for different operations.

[0087] Another configuration involves interplanetary missions, where the solar cell array 22 could become extremely hot or extremely cold as the distance to the sun changes. Alternatively, the temperature of the solar cell array 22 could change dramatically if the mobile environment changes, such as when landing on an asteroid or other object or planet. These temperature changes would alter the voltage generated by the solar cells 14 and the required string length, which could be dramatic.

[0088] Figure 21 shows the layout of a solar cell 14 consisting of three flex sheet substrates 12, 12b, and 12c. Each substrate 12a, 12b, and 12c has a 3 (horizontal) × 27 (vertical) grid of solar cells 14. The lower part 12d of each substrate 12a, 12b, and 12c has 58 solar cells 14 that generate 100V. The upper part 12e of each substrate 12a, 12b, and 12c has 19, 19, and 20 solar cells 14, respectively, for a total of 58 solar cells 14. There are some locations for solar cells 14 that do not contain solar cells 14, as illustrated by the rectangular element 70 occupied by the diagonal lines. The curved lines 72 generally show how the solar cells 14 within each part 12d, 12e of each substrate 12a, 12b, and 12c are connected in series in a string. There are eight pairs of SPST switches 54, indicated by triangles, and the switches 54 can be reconfigured so that each of the lower portions 12d is a single string, and the upper portions 12e of each substrate 12a, 12b, and 12c are connected in series together within a single string. In this configuration, all the solar cells 14 are in a series-connected string having 58 solar cells 14. This configuration generates 100V against a typical geosynchronous (GEO) near-earth environment after 10 years of radiation has caused voltage loss.

[0089] Figure 22 shows how the layout of Figure 21 can be reconfigured using switch 54. When connected in series, the lower portion 12d and upper portion 12e of each board 12a, 12b, and 12c contain strings with lengths of 77(58+19), 77(58+19), and 78(58+20) solar cells 14, respectively. The strings will generate 132V, 132V, and 134V, respectively, under GEO conditions. Alternatively, in high-temperature environments, a 100V output can be maintained.

[0090] In conclusion, this explanation involves adding switches 54 and wiring to the solar cell array 22 to achieve reconfigurable functionality. Applying switches and wiring to conventional solar cell arrays would be extremely complex and expensive. What now makes the reconfigurable solar cell array 22 possible is the use of wiring traces within the substrate 12 instead of conventional wires. Reconfigurability requires wiring many or all solar cells 14 in parallel, while conventional wiring only has start and end connections. Traces on the substrate 12 can have many connections made to them at any point down the length of the trace. Thus, traces can be routed under the solar cells 14, very easily providing circuit output lines for all solar cells 14. Furthermore, the front contacts 32 and rear contacts 34 of the solar cells 14 are available in the corner areas 26. Switches 54 can be added to achieve reconfigurability without consuming the area of ​​panel 10a. Figures and descriptions illustrate how reconfigurability changes the number of solar cells 14 in the string and the resulting output voltage at the solar cell level 14. Alternatively, reconfigurability allows strings to be connected together to build voltages into larger blocks.

[0091] In conventional solar cell arrays, adding a switch would require end tabs, wiring, a switch, and circuit wiring. These components would have to be located between any two solar cells that can be reconfigured. In addition to the effort involved, these components would take up a considerable amount of panel area, thereby reducing power generation.

[0092] manufacturing Embodiments of the present disclosure will be described in reference to a method for manufacturing a solar cell 14, a solar cell panel 10a, and / or a satellite, including steps 76 to 88 shown in Figure 23, the resulting satellite 90 having a solar cell panel 10a made of solar cells 14 is shown in Figure 24.

[0093] As shown in Figure 23, in the pre-manufacturing stage, exemplary methods 74 may include the specification and design 76 of the solar cells 14, solar cell panels 10a, and / or satellite 90, and the procurement of these materials 78. In the manufacturing stage, the manufacturing 80 of the components and subassemblies of the solar cells 14, solar cell panels 10a, and / or satellite 90, and system integration 82 are carried out, which include the manufacturing of the solar cells 14, solar cell panels 10a, and / or satellite 90. Subsequently, the solar cells 14, solar cell panels 10a, and / or satellite 90 may undergo authorization and delivery 84 for use in operation 86. The solar cells 14, solar cell panels 10a, and / or satellite 90 may also be scheduled for maintenance and servicing 88 (including modifications, reconfigurations, and refitting) before launch.

[0094] Each step of Method 74 may be carried out or performed by a system integrator, a third party, and / or an operator (e.g., a customer). For the purposes of this Specification, the system integrator may include, but is not limited to, any number of manufacturers and subcontractors of major systems of solar cells, solar cell panels, satellites, or spacecraft; the third party may include, but is not limited to, any number of vendors, subcontractors, and suppliers; and the operator may be a satellite communications company, a military organization, a service organization, etc.

[0095] As shown in Figure 24, the satellite 90 manufactured by the exemplary method 74 may include a system 92, a body 94, a solar cell panel 10a consisting of solar cells 14, and one or more antennas 96. Embodiments of the system 92 included in the satellite 90 include, but are not limited to, one or more of a propulsion system 98, an electrical system 100, a communications system 102, and a power system 104. Any number of other systems 92 may also be included.

[0096] Figure 25 shows a solar cell panel 10a in the form of a functional block diagram according to one embodiment. The solar cell panel 10a consists of a solar cell array 22 comprising one or more solar cells 14 individually mounted on a substrate 12. Each solar cell 14 absorbs light 106 from a light source 108 and generates an electrical output 110 in response.

[0097] At least one of the solar cells 14 has at least one trimmed corner portion 24 that defines a corner region 26, thereby keeping an area 28 of the substrate 12 exposed even when the solar cell 14 is mounted on the substrate 12. When multiple solar cells 14 are mounted on the substrate 12, the corner regions 26 of adjacent solar cells 14 are aligned, thereby exposing an area 28 of the substrate 12.

[0098] The exposed area 28 of the substrate 12 includes one or more corner conductors 20 that are attached to the substrate 12, printed on the substrate 12, or incorporated into the substrate 12, and one or more electrical connections between the solar cell 14 and the corner conductor 20 are made within a corner region 26 formed by at least one trimmed corner portion 24 of the solar cell 14.

[0099] The corner region 26 formed by the trimmed corner portion 24 includes at least one contact, for example, a front contact 32 on the front of the solar cell 14 and / or a rear contact 34 on the back of the solar cell 14, to form an electrical connection between the corner conductor 20 and the solar cell 14. The electrical connection includes an upward / downward and / or leftward / rightward series connection that determines the flow of power through the solar cell 14 and may include one or more bypass diodes 44.

[0100] The exposed region 28 of the substrate 12 includes at least one switch 54 located within a corner region 26 defined by a trimmed corner 24 adjacent to the solar cell 14, for changing the current path between the solar cell 14 and the electrical connection. The substrate 12 includes one or more traces connected to the switch 54 for making electrical connections between the solar cells 14.

[0101] Switch 54 reconfigures the string length for the electrical connection between the solar cells 14 in response to a control signal. Switch 54 also reconfigures the connections between strings, allowing for the reconfiguration of series connections and outputs between strings. Switch 54 may be a single-pole single-throw (SPST) switch or a double-pole single-throw (DPST) switch, and may be sold individually, in pairs, or packaged as needed.

[0102] Experimental results To demonstrate the reconfiguration of the array's string length, a solar cell array was constructed using a flexible circuit board based on a corner conductor design.

[0103] Figure 26A is an image of a demonstration solar cell array consisting of 12 solar cells arranged in three stages, with 4 solar cells in each stage. Electrical connections are made within the corner areas to provide either series connections or string terminations. The current flow or conductive path was selected by welding metal foil jumpers in place. Instead of metal jumpers, pairs of wires extending beyond the perimeter of the solar cell array were added at several locations.

[0104] Figure 26B is an image showing a magnified view of one of the corner regions illustrating the electrical connections between the front contacts, rear contacts, bypass diodes, and solar cells.

[0105] Figure 26C is a version of Figure 26B, showing the electrical connection between the upper left and lower left solar cells, indicated by dark lines drawn on the conductive paths. One conductive path connects the back contacts of the upper left solar cell to the front contacts of the lower left solar cell, allowing current to flow downwards. Another conductive path connects the back contacts of the lower left solar cell through a bypass diode.

[0106] The electrical connection between the top right solar cell and the bottom right solar cell is rotated 180 degrees compared to the electrical connection between the top left solar cell and the bottom left solar cell. As a result, current flows from the bottom right solar cell to the top right solar cell.

[0107] The jumpers are positioned for series connections. By changing the position of the jumpers, the current flow can be terminated within the buried traces.

[0108] Figure 26D is an image of another corner region where wires have been added instead of jumpers. Multiple wires can be short-circuited together to function like a jumper, or the wires can be separated to function as if there were no jumper.

[0109] In this demonstration, using jumpers or wires, the configuration of a solar cell array with 12 solar cells can be changed from two strings with 6 solar cells each to three strings with 4 solar cells each.

[0110] Figure 26E is a graph of photocurrent-voltage (LIV) measurements of a solar cell array under AM0 (air mass coefficient relative to zero atmosphere) illumination. Measurements were performed using a configuration of two strings with six solar cells each and three strings with four solar cells each. Changes in voltage indicate changes in string length.

[0111] Furthermore, this disclosure includes embodiments as provided for in the following clauses. Clause 1. A solar cell array comprising one or more solar cells mounted on a substrate, the substrate comprising one or more electrical connections to the solar cells, and the substrate comprising one or more switches for changing the string length of one or more of the solar cells by changing the current path between one or more of the solar cells and one or more of the electrical connections. Clause 2. The solar cell array according to Clause 1, wherein when at least one of the solar cells having one or more trimmed corners is mounted on a substrate, an area of ​​the substrate remains exposed, and the exposed area of ​​the substrate includes at least one of the switches. Clause 3. The solar cell array according to Clause 2, wherein at least one of the solar cells is mounted on a substrate such that a corner region defined by the trimmed corner of at least one adjacent solar cell is aligned, thereby exposing an area of ​​the substrate. Clause 4. A solar cell array according to any one of Clauses 1 to 3, wherein at least one of the switches is located within a corner area defined by a trimmed corner adjacent to at least one of the solar cells. Clause 5. A solar cell array as described in any one of Clauses 1 to 4, wherein a switch changes the string length of one or more of the solar cells in response to one or more control signals. Clause 6. A solar cell array as described in any one of Clauses 1 to 5, wherein the switch modifies the string length to allow for series connection between multiple strings and reconfigurability of the output. Clause 7. A solar cell array as described in any one of Clauses 1 to 6, wherein a switch combines two or more strings of solar cells for a desired voltage output in response to one or more control signals. Clause 8. A solar cell array as described in any one of Clauses 1 through 7, wherein the switch is a single-pole single-throw (SPST) switch. Clause 9. A solar cell array as described in any one of Clauses 1 through 8, wherein the switch is a bipolar single-throw (DPST) switch. Clause 10. A solar cell array as described in any one of Clauses 1 to 9, wherein the substrate includes one or more traces connected to switches for making electrical connections between solar cells. Clause 11. A method for manufacturing a solar cell array, comprising mounting one or more solar cells to a substrate, wherein the substrate includes one or more electrical connections to the solar cells, and the substrate includes one or more switches for changing the string length of one or more of the solar cells by changing the current path between one or more of the solar cells and one or more of the electrical connections. Clause 12. The method according to Clause 11, wherein when at least one of the solar cells having one or more trimmed corners is mounted on a substrate, an area of ​​the substrate remains exposed, and the exposed area of ​​the substrate includes at least one of the switches. Clause 13. The method according to Clause 12, wherein at least one of the solar cells is mounted on a substrate such that a corner area defined by the trimmed corner of at least one adjacent solar cell is aligned, thereby exposing an area of ​​the substrate. Clause 14. The method according to any one of Clauses 11 to 13, wherein at least one of the switches is located within a corner area defined by a trimmed corner adjacent to at least one of the solar cells. Clause 15. The method described in any one of Clauses 11 to 14, wherein a switch changes the string length of one or more of the solar cells in response to one or more control signals. Clause 16. The method of any one of Clauses 11 to 15, wherein the switch modifies the string length to allow for series connection between multiple strings and reconfigurability of the outputs. Clause 17. The method according to any one of Clauses 11 to 16, wherein a switch combines two or more strings of solar cells for a desired voltage output in response to one or more control signals. Clause 18. The method described in any one of Clauses 11 to 17, wherein the switch is a single-pole single-throw (SPST) switch. Clause 19. The method described in any one of Clauses 11 to 18, wherein the switch is a bipolar single-throw (DPST) switch. Clause 20. The method according to any one of Clauses 11 to 19, wherein the substrate includes one or more traces connected to a switch for making electrical connections between solar cells. Clause 21. A method comprising activating one or more switches in one or more electrical connections to one or more solar cells for changing the string length of one or more solar cells by changing the current path between one or more solar cells and one or more electrical connections.

[0112] conclusion The above description of the embodiments is provided for illustrative and explanatory purposes only and is not intended to be exhaustive or limit the embodiments described. Numerous alternative, modified, and altered forms may be used instead of the specific elements described above.

Claims

1. A solar cell array, the solar cell array comprising: A solar cell (14) attached to a substrate (12) and having a front surface and a back surface; the substrate includes an electrical connection (20) to the solar cell; the substrate includes a switch (54) for changing a length of the string of solar cells by changing a current flow path between the solar cells and the electrical connections; When the solar cell (14) having trimmed corners (24) is attached to the substrate, an area (28) of the substrate (12) remains exposed; each of the switches connects one of the solar cells to either a string output line or a bypass diode (44) and one of the solar cells and an adjacent solar cell; at least one of the solar cells (14) is attached to the substrate (12) such that corner regions (26) defined by the trimmed corners (24) of adjacent solar cells (14) are aligned to expose the area (28) of the substrate; the bypass diode (44) is attached to the exposed area (28) of the substrate or the bypass diode (44) is attached to the backside of the solar cell (14) adjacent the trimmed corner.

2. The solar cell array of claim 1 , wherein the switch (54) varies the string length of the solar cells (14) in response to a control signal.

3. 3. The solar cell array of claim 1 or 2, wherein the switch varies the string length to allow series connection between multiple strings and output reconfigurability.

4. The solar cell array of any one of claims 1 to 3, wherein the switches (54) combine two or more strings of the solar cells (14) for a desired voltage output in response to a control signal.

5. The solar cell array of any one of claims 1 to 4, wherein the switch (54) is a single-pole, single-throw (SPST) switch.

6. The solar cell array of any one of claims 1 to 4, wherein the switch (54) is a double-pole single-throw (DPST) switch.

7. The solar cell array of any one of claims 1 to 6, wherein the substrate (12) includes traces connected to the switches to make the electrical connections between the solar cells (14).

8. A method of operating a solar cell array according to any one of claims 1 to 7, comprising the steps of: activating the switch (54) in the electrical connection (20) to the solar cell (14) to change the string length of the solar cell by changing the current flow path between the solar cell and the electrical connection. The method includes:

9. 1. A method for manufacturing a solar cell array, the method comprising: Attaching a solar cell having a front surface and a back surface to a substrate Including, the substrate includes an electrical connection to the solar cell; the substrate includes a switch for changing a string length of the solar cells by changing a current flow path between the solar cells and the electrical connections; an area of ​​the substrate is left exposed when the solar cell having trimmed corners is attached to the substrate; Each of the switches connects one of the solar cells to either a string output line or a bypass diode and one of the solar cells and an adjacent solar cell; the solar cells are attached to the substrate such that corner regions defined by the trimmed corners of adjacent solar cells are aligned to expose the area of ​​the substrate; The method wherein the bypass diode is attached to the exposed area of ​​the substrate or the bypass diode is attached to the backside of the solar cell adjacent the trimmed corner.

10. The method of claim 9 , wherein the switch varies the string length of the solar cells in response to a control signal.

11. 11. The method of claim 9 or 10, wherein the switch varies the string length to allow series connection between multiple strings and output reconfigurability.

12. 12. The method of any one of claims 9 to 11, wherein the switches combine two or more strings of the solar cells for a desired voltage output in response to a control signal.

13. 13. The method of any one of claims 9 to 12, wherein the switch is a single-pole, single-throw (SPST) switch.

14. 13. The method of claim 9, wherein the switch is a double-pole single-throw (DPST) switch.

15. 15. The method of any one of claims 9 to 14, wherein the substrate includes traces connected to the switch for making the electrical connections between the solar cells.

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