JP2023169172A - Solar cell array with bypassed solar cells - Google Patents

Abstract

To provide a solar array in which a failure occurring in one or more solar cells in a string does not greatly compromise supplied power.SOLUTION: In a solar cell array comprising four solar cells 14 each having at least one cropped corner, the four solar cells 14 are attached to a flex circuit substrate such that adjacent corner regions are aligned, thereby exposing an area of the flex circuit substrate. Front contacts 32 and back contacts 34 for the solar cells 14 extend into the exposed area of the flex circuit substrate. Also included are corner conductors 20 for making one or more electrical connections between the front contacts 32 and the back contacts 34 of the solar cells 14, as well as bypass diodes 44, string length switches 54a and bypass switches 54b.SELECTED DRAWING: Figure 15

Description

TECHNICAL FIELD This disclosure relates generally to solar cell panels and, more particularly, to solar cell arrays having bypassed solar cells.

A typical spaceflightable solar cell panel assembly involves building a solar cell array consisting of long strings of solar cells connected in series. These strings are variable in length, ie the number of solar cells, and can be very long.

Traditional solar cell arrays are constructed with a fixed number of solar cells to generate the required output voltage. For example, a string of 50 solar cells connected in series produces an output voltage of 100V. A failure of one or more of the solar cells in the string can significantly impair the power provided by all 50 solar cells.

This results in extensive efforts in testing, validating, and qualifying materials and processes to ensure maximum longevity and success for solar cell arrays. However, such efforts increase costs and reduce innovation. Additionally, some missions are so risky that they are avoided entirely.

Therefore, what is needed is a means to address malfunctions in the operation of a solar cell array or the expected output voltage is not delivered during its lifetime.

To overcome the limitations of the prior art described above, and to overcome other limitations that will become apparent upon reading and understanding this specification, the present disclosure includes one or more solar cells attached to a substrate, the substrate comprising: a solar cell comprising one or more electrical connections to the solar cells, the substrate comprising one or more switches for bypassing one or more of the electrical connections to one or more of the solar cells; Cell arrays, methods and devices are described.

When at least one of the solar cells having one or more cropped corners is attached to a substrate, an area of the substrate remains exposed, and an area of the substrate that remains exposed is attached to at least one of the switches. Including one. At least one of the solar cells is attached to the substrate such that a corner area defined by a pruned corner of an adjacent one of the solar cells is aligned, thereby exposing an area of the substrate. . At least one of the switches is located within a corner region defined by the cropped corner adjacent to at least one of the solar cells.

The solar cell, one or more bypass diodes, and the switch are electrically connected in parallel. Furthermore, the switch is controlled by one or more control signals.

The switch diverts the current away from one or more of the solar cells. In particular, the switch, when closed, connects the front and back contacts of one or more of the solar cells and current is diverted away from the one or more of the solar cells.

There is also a switch for adding or removing one or more of the solar cells from the string of solar cells, the length of the string being changed to change the voltage produced by the string. Ru.

Reference is now made to the drawings, wherein like reference numbers represent corresponding parts throughout the drawings.

The conventional structure of a solar cell panel is shown. The conventional structure of a solar cell panel is shown. A and B illustrate an improved structure of a solar cell panel according to one example. A and B illustrate alternative constructions of solar cell panels according to one example. 3A-B and 4A-B illustrate the front side of an exemplary solar cell that may be used in the improved solar cell panels of FIGS. 4A-B. 6 shows a back view of the exemplary solar cell of FIG. 5. FIG. 2 illustrates cells arranged in a two-dimensional (2D) grid of an array, according to one example. FIG. 6 shows an example of an array in which one or more bypass diodes are added to exposed areas of the substrate in corner regions. An example is shown in which the bypass diode is attached to the back side of the cell and the interconnect or contact for the bypass diode extends into the corner region between the front and back contacts. 10 shows a front view of the example of FIG. 9 in which interconnects or contacts for the bypass diode extend into the corner regions between the front and back contacts; FIG. The cell of FIGS. 9 and 10 arranged in an array of 2D grids and attached to a substrate, wherein the bypass diode is attached to the back side of the cell and the contacts for the bypass diode extend into the corner regions of the cell. The cells of FIGS. 9 and 10 are shown. FIG. 6 illustrates an upward/downward series connection between cells of an array, according to one embodiment; FIG. FIG. 7 illustrates a left/right series connection between cells of an array, according to one embodiment; FIG. Figure 2 shows a schematic diagram of a string of two solar cells with multiple switches and connection paths shown. Figure 3 shows how diversion of the solar cell includes a single diversion switch connecting the front and back contacts of the solar cell. A set of three solar cells in a vertical row is shown. A single integrated device is shown that combines switch functionality with a bypass diode. The combined switch is shown adjacent to the bypass diode. A method of manufacturing a solar cell, solar cell panel, and/or satellite according to one example is described. 2 shows a resulting satellite having a solar cell panel of solar cells, according to one example; FIG. 1 is a diagram of a solar cell panel in the form of a functional block diagram, according to one example; FIG. A to H show experimental results in which a solar cell array based on a corner conductor design and using a flex circuit board was constructed to demonstrate the reconfiguration of the string length of the array.

In the following description, reference is made to the accompanying drawings, which form a part of this application, and are shown for the purpose of illustrating particular examples in which the present disclosure may be practiced. It should be understood that other embodiments may be utilized and structural changes may be made without departing from the scope of this disclosure.

A new approach to the design of solar cell arrays, used for example in spaceflight power applications, is based on electrical connections between solar cells within the array.

These new approaches rearrange solar cell components and the arrangement of solar cells within an array. Instead of connecting solar cells into long linear strings and then assembling them on a substrate, the solar cells can be attached to the substrate individually, with the corner areas of adjacent cells aligned on the substrate, and the expose an area. Electrical connections between cells are made by corner conductors formed in these corner regions on or within the substrate. As a result, this approach presents a solar cell array design based on individual cells.

Thus, a single laydown process and layout can be used to manufacture solar cell arrays. Current flow between the solar cells will be assisted by conductors embedded within the substrate. These electrical connections define certain characteristics of the solar cell array, such as its dimensions, stay-out area, and circuit termination. This approach simplifies manufacturing, enables automation, reduces costs, and shortens delivery times.

1 and 2 illustrate a conventional structure of a solar cell panel 10, including a substrate 12, a plurality of solar cells 14 arranged in an array, and electrical connectors 16 between the solar cells 14. A half-sized solar cell 14 is shown in FIG. 1, and a full-sized solar cell 14 is shown in FIG. The space solar cell 14 is obtained from a round germanium (Ge) substrate starting material and later processed into a semi-rectangular shape to enhance dense packing onto the solar cell panel 10. This wafer is often diced into one or two solar cells 14, which are described herein as half-size or full-size solar cells 14. Electrical connectors 16 that provide electrical connections between solar cells 14 are made along the long parallel edges between solar cells 14 . The resulting string of connected solar cells 14 can be constructed to have a length of any number of solar cells 14, so that these series connections (cell to cell) are not attached to the substrate. Complete it with The completed string of solar cells 14 is then applied and attached to the substrate 12.

In FIG. 2, wires 18 are attached to the ends of the strings of solar cells 14, either to electrically connect the strings to other strings or to terminate the wires into a circuit and to connect the solar cells 14. This is to cut off the current to the 14 arrays here. Connections between strings and circuit terminations are typically made on the substrate 12 and typically using traces 18. However, some solar cell panels 10 use a printed circuit board (PCB) type material inlaid with conductors.

Adjacent strings of connected solar cells 14 can run parallel or anti-parallel. Additionally, strings of connected solar cells 14 may be aligned or unaligned. There are many competing influences on the layout of the solar cells 14, such that there are regions where the solar cells 14 are parallel or anti-parallel, aligned or unaligned. do.

3A and 3B illustrate an improved arrangement and structure of a solar cell panel 10a according to one embodiment, and FIG. 3B is an enlarged view of the detail within the dashed circle of FIG. 3A. 5-13, various components of solar cell panel 10a are shown and described in more detail.

Solar cell panel 10a includes a substrate 12 for solar cells 14 having one or more corner conductors 20 thereon. In one embodiment, substrate 12 is a multilayer substrate 12 comprised of one or more Kapton® (polyimide) layers separating one or more patterned metal layers. Substrate 12 may be attached to a large rigid substrate 10a similar to a conventional assembly. Alternatively, the substrate 12 can be mounted to a lighter, thinner frame or panel 10a for mounting or deployment.

A plurality of solar cells 14 are attached to substrate 12 in a two-dimensional (2-D) grid of array 22 . In this example, array 22 is comprised of 96 solar cells 14 arranged in 4 rows by 24 columns, although any number of solar cells 14 may be used in different implementations. ,It recognized.

Solar cell 14 has pruned corners 24 that define corner regions 26, as shown by the dashed circles. A plurality of solar cells 14 are attached to substrate 12 and corner regions 26 of adjacent solar cells 14 are aligned to expose areas 28 of substrate 12. The exposed area 28 of the substrate 12 includes one or more corner conductors 20 within the corner region 26 created by the cropped corner 24 of the solar cell 14 and between the solar cell 14 and the corner conductor 20. One or more electrical connections are made.

In this example, the corner conductors 20 may be attached to the substrate 12, printed on the substrate 12, embedded within the substrate 12, or embedded in the substrate 12 before and/or after the solar cell 14 is attached to the substrate 12. Conductive paths deposited thereon facilitate connections between adjacent solar cells 14. The connection between solar cell 14 and corner conductor 20 is made after solar cell 14 is attached to substrate 12.

In one embodiment, four adjacent solar cells 14 are aligned on the substrate 12 and four trimmed corners 24, one from each solar cell 14, meet together at a corner region 26. There is. The solar cells 14 are then individually attached to the substrate 12 and rest on the corner conductors 20 to form an electrical connection between the solar cells 14 and the corner conductors 20.

Solar cell 14 may be attached to substrate 12 as a CIC (Cell, Interconnect, Cover Glass) unit. Alternatively, an uncoated solar cell 14 is assembled on the substrate 12, followed by attaching an interconnect to the solar cell 14, followed by a cover glass for a single cell solar cell 14, a cover glass for a multi cell solar cell 14, a cover glass for a multi cell solar cell 14, and a cover glass for a multi cell solar cell 14. A polymeric cover sheet or spray encapsulant may also be applied. This assembly protects the solar cell 14 from damage that would limit its performance.

4A and 4B illustrate an alternative construction of a solar cell panel 10a, according to one example, and FIG. 4B is an enlarged view of the detail within the dashed circle of FIG. 4A. In this embodiment, only a small number of corner conductors 20 are printed on or integrated into the substrate 12. Instead, the majority of corner conductors 20 are contained within a power routing module (PRM) 30 that is attached to substrate 12.

FIG. 5 shows the front side of an exemplary solar cell 14 that may be used in the improved solar cell panel 10a of FIGS. 3A-B and 4A-B. The solar cell 14 is a CIC unit and is a half-sized solar cell 14. (Full-sized solar cells 14 could also be used.)

As shown by the dashed circle, the solar cell 14 is manufactured with at least one pruned corner 24 defining a corner region 26 , and the corner region 26 defined by the pruned corner 24 is includes at least one contact 32 , 34 for electrical connection with the solar cell 14 . In the embodiment shown in FIG. 5, the solar cell 14 has two cropped corners 24, each having a front contact 32 on the front side of the solar cell 14 and a back contact 32 on the back side of the solar cell 14. , with contacts 32 and 34 extending into corner region 26 . (A full-sized solar cell 14 would have four cropped corners 24, each having a front contact 32 and a back contact 34.)

Trimmed corners 24 increase the utilization of round wafer starting material for solar cells 14. In a conventional panel 10, these trimmed corners 24 would provide unused space above the panel 10 after the solar cells 14 are attached to the substrate 12. However, the new approach described in this disclosure takes advantage of this unused space. Specifically, a metal foil interconnect comprising corner conductors 20, front contacts 32, and back contacts 34 is moved to corner region 26. In contrast, existing CICs have interconnects attached to the front of the solar cell 14 and connected to the back (where the connection occurs) during string fabrication.

The current generated by the solar cell 14 is collected at the front face of the solar cell 14 by a grid 36 of narrow metal fingers 38 and wider metal busbars 40 connected to either front contact 32 . A balance exists between adding metal to the grid 36, reducing the light incident on the solar cell 14 and its output power, and having more metal reduces the resistance. Bus bar 40 is a low resistance conductor that carries high current and also provides redundancy in the event that front contact 32 is severed. Optimization generally requires short busbars 40 passing directly between front contacts 32. By having the front contact 32 at the pruned corner 24, the busbar 40 moves away from the perimeter of the solar cell 14. This is accomplished while simultaneously minimizing the length of the busbar 40 and the obscuring of the light. In addition, this also shortens the fingers 38. This reduces the parasitic resistance of the grid 36 since the fingers 38 are shorter in length and carry less total current. This creates a design preference to move the front contact 32 and the connecting bus bar 40 to provide a shorter narrow finger 38.

FIG. 6 shows the back side of the exemplary solar cell 14 of FIG. The back side of solar cell 14 has a metal back layer 42 coupled to both back contacts 34 .

FIG. 7 shows solar cells 14 arranged in a 2D grid of arrays 22, according to one embodiment. Array 22 includes a plurality of solar cells 14 attached to substrate 12 with corner regions 26 of adjacent ones of the solar cells 14 aligned to expose regions 28 of substrate 12. Electrical connections (not shown) between solar cells 14 are made at front contacts 32 and back contacts 34 of solar cells 14 and corner conductors 20 (not shown) formed on or in exposed areas 28 of substrate 12. (not shown) in exposed areas 28 of substrate 12.

During assembly, solar cells 14 are individually attached to substrate 12. This assembly can take place directly on the support surface, ie the substrate 12, which can be either rigid or flexible. Alternatively, the solar cells 14 could be assembled into a 2D grid of arrays 22 on a temporary support surface and then transferred to the final support surface, ie, the substrate 12.

FIG. 8 shows one embodiment of array 22 in which one or more bypass diodes 44 have been added to exposed areas 28 in corner regions 26 of substrate 12 for use in one or more electrical connections. . The bypass diode 44 protects the solar cell 14 in the event that the solar cell 14 is no longer able to generate current, which may also be due to partial shading. However, in that case, the solar cell 14 is reverse biased. In one embodiment, bypass diode 44 is attached to substrate 12 in corner region 26 independent of solar cell 14 .

FIG. 9 shows that a bypass diode 44 is attached to the back side of the solar cell 14 and that an interconnect or contact 46 for the bypass diode 44 is connected to the back layer 42 and further connected to the corner between the front contact 32 and the back contact 34. One embodiment is shown extending into region 26.

FIG. 10 is a front view of the embodiment of FIG. 9 in which an interconnect or contact 46 for a bypass diode 44 (not shown) extends into corner region 26 between front contact 32 and back contact 34. shows.

FIG. 11 shows the solar cells 14 of FIGS. 9 and 10 arranged in a 2D grid of arrays 22 and attached to the substrate 12, but in which bypass diodes 44 (not shown) are connected to the backside of the solar cells 14. A contact 46 for the bypass diode 44 extends into the corner region 26 of the solar cell 14 .

One advantage of this approach is that the layouts shown in FIGS. 7, 8, and 11 are generalized layouts. In particular, these layouts can be repeated over any dimensions of panel 10a desired by the customer. This greatly simplifies the assembly, rework, testing, and inspection process.

The arrangement of solar cells 14 and bypass diodes 44 is conventional. The series connection of solar cells 14 and the electrical connections to the string terminations are important customizations for the end customer and are done independently of the layout. The front contact 32 and the back contact 34 in the corner area 26 of the solar cell 14 must be connected. This can be done in many combinations to route the current through the desired path.

A connection is made between the solar cell 14 and the corner conductor 20. A front contact 32 and a back contact 34 of the solar cell 14 are present at each corner region 26 for attachment to the corner conductor 20. Interconnectors for the front contact 32 and back contact 34 of each solar cell 14 may be welded, soldered, or otherwise attached to the corner conductor 20 to provide a conductive path 20 , 32 , 34 for routing current to the exterior of the solar cell 14 . It is joined in the following manner.

Corner conductors 20 can be used to make any customizations in electrical connections. Adjacent solar cells 14 can be electrically connected to conduct current vertically or horizontally, as desired by a particular design. Current flow can also be routed around stay-out zones if desired. The length and width of the solar cell array 22 can be set as desired. Also, the width of array 22 may vary depending on its length.

In one embodiment, the electrical connections are series connections that determine the flow of current through the plurality of solar cells 14. This may be achieved by the connection schemes shown in FIGS. 12 and 13, with FIG. 12 showing an upward/downward series connection 48 between the solar cells 14 of the array 22, and FIG. A left/right series connection 50 between solar cells 14 is shown. In both FIGS. 12 and 13, these series connections 48, 50 are the electrical connections between the front contact 32 and back contact 34 of the solar cell 14 and the bypass diode 44; This is accomplished using corner conductors 20 formed on or within exposed areas 28 of substrate 12. These series connections 48, 50 determine the flow of current (power) through the solar cell 14, as shown by arrow 52.

Corner conductors 20 between solar cells 14 can take many forms. The corner conductors 20 could be completed using electrical wires with electrical connections made at both ends in a manner that could be soldering, welding, conductive adhesive, or other treatments. In addition to electrical wires, metal foil connectors similar to interconnects could also be applied. Metal conductor paths or traces (not shown) may also be incorporated into substrate 12.

In summary, this new approach allows solar cells 14 to be individually placed on the substrate 12 such that the corner regions 26 of two, three, or four adjacent solar cells 14 are aligned on the substrate 12. It is to be attached to. Solar cells 14 may be positioned such that trimmed corners 24 are aligned and corner regions 26 are adjacent, thereby exposing areas 28 of substrate 12. Electrical connections between solar cells 14 are made within these corner regions 26 to the front and back contacts 32 and 32 of solar cells 14, to bypass diodes 44, and to corners on or within exposed areas 28 of substrate 12. These conductive paths are used to create strings of solar cells 14 in series connections 48, 50 including circuits.

Solar Cell Arrays with Detoured Solar Cells Space-based solar cell arrays 22 are generally not maintainable. Therefore, defects are a major concern, leading not only to the avoidance of some missions but also to extensive quality programs.

Solar cell array 22 generates power by linking together a number of solar cells 14 to generate an output voltage. In one example, a string of 50 solar cells 14 in series produces an output voltage of 100V. Failure of one or more solar cell arrays 14 within a string can significantly impair the power provided by all 50 solar cells 14.

The present disclosure provides a mechanism to bypass solar cells 14, thus not compromising the string. Also, the length of the string can be changed by adding or removing solar cells 14. Collectively, these capabilities allow solar cell array 22 to continue generating power in the event of a solar cell 14 failure.

Solar cells 14 are typically connected in series within a string. A single triple junction solar cell 14 in the string produces approximately 2V. The photocurrent comes out from the back side (i.e., p-side) of the solar cell 14, and the back side of the first solar cell 14 is connected in series with the front side (i.e., n-side) of the second solar cell 14. . The photocurrent exits again from the back side of the second solar cell 14. The current is constant through the solar cells 14 connected in series, but derives 2V from each additional solar cell 14.

An important design specification is the voltage required for system operation. This is often 100V, but can vary widely.

Damage to the solar cells 14, bypass diodes 44, or their electrical connections can significantly reduce the power provided by the string. Due to the series-connected nature of the string, failure of one or more solar cells 14 can reduce output by 50% or more.

The present disclosure describes bypassing the solar cell 14 and its bypass diode 44 from the string, resulting in the solar cell 14 being removed from the string and causing a voltage drop in the string. The string would also change by adding solar cells 14 to the string after removing them from the string to maintain output voltage and peak power generation. Typically, the length of the string will be maintained or increased to provide a 100V output without degradation due to the bypassed solar cells 14.

FIG. 14 shows a schematic diagram of a string of two solar cells 14 attached to a substrate 12, the substrate 12 containing one or more electrical connections to the solar cells 14, and each solar cell 14 having a It has a diode 44. Each solar cell 14 also has a set of one or more string length switches 54a for changing the length of the string, and a bypass switch 54b for bypassing the solar cell 14, thereby 14.

Solar cell 14 includes a current source, a shunt resistor, and a diode, which is a common circuit representation. This simplifies consideration of how solar cell array 22 may vary. Shadowing or destruction of the solar cell 14 will reduce the current source. Damage to solar cell 14 can reduce shunt resistance.

Interconnectors 56 are also shown, each of these interconnectors 56 comprising two flange elements with parallel planes joined by a web element, thus resembling the letter H with its sides inclined looks like. Interconnect 56 is a piece of metal foil used to connect devices (solar cell 14, bypass diode 44, switch 54) to conductor 20.

Connections 58 between interconnects 56, devices 14, 44, 54, and conductors 20 are shown as small squares. These connections 58 can be soldered or welded connections 58.

The conductors 20 could possibly be wires, but a complex network of electrical connections between the solar cells 14 would be prohibited and would require extensive effort and occupation of the panel 10a area. However, the use of corner conductors 20 in solar cell array 22 makes this approach possible. This layout of solar cell 14 places all the necessary conductors 20 in close proximity (in corner region 26) and allows devices 14, 44, 54 to also be present in corner region 26.

Solar cells 14 can then be assembled onto a substrate 12, such as a readily available flex circuit board 12, using space-certified construction methods. The flex circuit board 12 has metal traces that can form the wiring pattern of the electrical connections shown. These electrical connections would be virtually impossible in conventional solar cell arrays, but are simplified in the corner connection layout of the present disclosure.

FIG. 14 shows a string with two solar cell 14 lengths. This is not very useful in practice, but helps demonstrate the functionality of the present disclosure. The polarity is such that when illuminated, photocurrent flows upward within each solar cell 14, as indicated by the upwardly pointing arrow current source. The resulting voltage will also be larger at the top of the diagram (VX+ connection) rather than at the bottom. The two string length switches 54a on the right can control the output. The illustrated outputs include positive and negative polarities of the two outputs V1 and V2. V1- is fixed as the starting point of the solar cell array 22. After the bottom solar cell 14, a set of string length switches 54a can control the output to terminate to V1+. In this case, the upper solar cell 14 would be connected to V2-. The output of the upper solar cell 14 will then be switched to V2+ by a set of string length switches 54a. In this configuration there would be two outputs with the power of one solar cell 14 on each output.

The string length switch 54a could also be set such that the current continues to the upper solar cell 14 after the lower solar cell 14, albeit through two string length switches 54a. The current then continues through the upper solar cell 14 where the voltage increases. The output is then directed to V1+. V1+ has the same current as before, but now the voltage is doubled. Circuit lines V2- and V2+ can be connected together, avoiding any floating unconnected conductors.

If the solar cell 14 or diversion diode 44 is not operating properly, the left diversion switch 54b can be closed to divert the solar cell 14 and diversion diode 44 from the string. When closed, the switch 54b will create a low resistance path that bypasses the solar cell 14, resulting in the solar cell 14 having approximately 0 volts and little or no current flowing across it.

This operation will remove the solar cell 14 from the string resulting in a voltage drop across the string. To maintain output voltage and peak power generation, the string must also change, which requires another set of switches 54a to add functioning solar cells 14 to the string. Typically, the string length will be maintained or increased such that the string then provides a 100V output without degradation due to the bypassed solar cells 14.

Typical building blocks for space-based solar cell array 22 are solar cells 14 and bypass diodes 44. In this disclosure, the building blocks here become the solar cell 14, the diversion diode 44, the string length switch 54a, and the diversion switch 54b. This highly functional building block, when combined with a corner connection layout, can be used to construct solar cell arrays 22 with surprising functionality.

The resulting configuration will allow any single solar cell 14 or group of solar cells 14 to be bypassed. The current will then be routed away from solar cell 14 through diversion switch 54b. The string length could then be expanded as needed to reach the required output voltage. FIG. 14 shows switch control and bypass control at the level of individual solar cells 14. It is easy to modify the connections so that groups of solar cells 14 can be routed around as s-groups. This is similar to switching solar cells 14 as a group.

The detour diode 44 plays a role similar to that of the detour switch 54b. Diversion switch 54b is controlled through an external system that senses operation, determines switch configuration, and sends information to the switch. These operations are internal to the bypass diode 44 and automatic. If the forward bias applied to the bypass diode 44 is greater than 0.7V, current will automatically flow through the low resistance bypass diode 44. With appropriate sensing and control systems, bypass switch 54b could eliminate the need for bypass diode 44.

FIG. 15 shows how the solar cell 14 is bypassed by a single bypass switch 54b connecting the front contact 32 and back contact 34 of the solar cell 14 in a corner connection layout. Additionally, a set of string length switches 54a are used to adjust the string length.

A corner-connected layout is used in this example for a solar cell array 22 consisting of four solar cells 14 each having at least one pruned corner 24 . The solar cell 14 is attached to the substrate 12, i.e., the flex circuit board 12, such that the corner regions 26 of adjacent ones of the solar cells 14 resulting from the trimmed corners 24 are aligned, thereby exposing an area 28 of the substrate 12. can be attached to. Front contact 32 and back contact 34 of solar cell 14 extend within exposed area 28 of substrate 12 . Exposed area 28 of substrate 12 is also used to make one or more electrical connections between front contact 32 and back contact 34 of solar cell 14, as well as bypass diode 44, string length switch 54a, and bypass switch 54. It also includes a corner conductor 20.

The exposed area 28 of the substrate 12 also includes one or more diversion switches 54b for bypassing electrical connections to one or more of the solar cells 14, the switches 54b, when closed, The front contact 32 and the back contact 34 of one or more of the solar cells 14 are coupled in order to bypass electrical connections to one or more of the solar cells 14 . The corner connection layout simplifies the use of the bypass switch 54b because the front contact 32 and back contact 34 are physically adjacent to each other. Additionally, front contact 32 and back contact 34 are accessible to traces on flex circuit board 12.

The corner connection layout also provides another important capability for bypassing solar cells 14. Specifically, flex circuit board 12 may include traces underneath solar cell 14 that are electrically isolated from solar cell 14 .

Additionally, the exposed areas 28 of the substrate 12 can be used to modify the string of solar cells 14 by adding and/or removing one or more of the solar cells 14 from the string's electrical connections. It also includes one or more sets of switches 54a. The string is modified to change the voltage produced by the string.

Figure 16 shows a set of three solar cells in a vertical column. Busbars 40 are low resistance metal conductors on the surface of solar cell 14 that carry electrical current from individual narrow metal fingers 38 of grid 36 (not shown) to front contact 32 of solar cell 14 . Each end of the bus bar 40 is connected to a front contact 32 that can be connected to a trace on the flex sheet substrate 12. Back contact 34 is connected to the back surface of solar cell 14 .

The dashed lines are traces 60, 62 in or on the flex sheet substrate 12 below the solar cell 14 that are electrically isolated from the solar cell 14. These traces 60, 62 provide parallel current paths for the front contact 32 and back contact 34 of the solar cell 14 between each corner. These traces 60, 62 also provide a current path for bypassing the solar cell 14, allowing current to flow underneath the solar cell 14 when the solar cell 14 is bypassed. This is similar to the stay-out zone discussion found in some of the applications cross-referenced above.

The corner region 26 may also include a bypass diode 44 and a corner conductor 20 that supports the series connection of these solar cells 14. Current will flow through these three solar cells 14 from top to bottom.

A bypass switch 54b is also shown in corner area 26. Although only a single diversion switch 54b is needed in each corner region 26, a second diversion switch 54b in the corner region 26 provides additional protection from malfunctions.

Referring again to FIG. 15, switch 54 is shown as a single pole single throw (SPST) switch 54. Referring again to FIG. Such a switch 54 may be semiconductor-based, such as a silicon (Si) MOSFET (metal oxide semiconductor field effect transistor), or a gallium nitride (GaN) or silicon carbide (SiC) FET (field effect transistor), for example. and is available from multiple vendors for space applications.

However, to simplify assembly, the functions of switch 54 and bypass diode 44 could be combined into a single integrated device. A semiconductor or MEMS (microelectromechanical system) switch 54 could be fully integrated with the bypass diode 44 on a common semiconductor wafer or through various integration techniques.

A single integrated device 64 that combines the functionality of switch 54 and bypass diode 44 is shown in FIG. The thick dark lines represent conductive paths 66 through integrated device 64 within corner regions 26 . The short parallel lines labeled AF in integrated device 64 represent switches 54 that can change the resistance in that region from a very low value to a very high value. The diode symbol between switch E and C/D 54 represents bypass diode 44. The operation of these switches 54 controls the operation of the series pair circuit termination and the bypass operation of the solar cell 14 performed by the integrated device 64.

Device 64 in FIG. 17 has one more switch 54 than the layouts in FIGS. 14 and 15. This extra switch 54 allows termination of any solar cell 14 connected to device 64. Another way to understand this is that each solar cell 14 in the configuration can be terminated at either corner.

Not shown is integrated device 64 and its control of switch 54. This could be achieved through various communication strategies. A common method would be to continuously transmit information including addresses to identify integrated device 64 and switches 54 (A-F), and transmit the open and closed status of each switch 54. This continuous communication is generally accomplished by clock signals and information signals with power and ground conductors. These communication lines can be integrated within the flex circuit board 12. Because they do not carry much power or current, the size of the conductors can be much smaller than other traces and can be integrated into the flex circuit board 12 without difficulty. There are many other ways to convey information, such as through wireless communications, which can be electromagnetic or optical.

It may be desirable to make switch 54 from one semiconductor material and bypass diode 44 from another semiconductor material. For example, gallium nitride (GaN) is preferred for the combination switch 54, while Si is preferred for the bypass diode 44. These functions can be separated into separate devices as shown in FIG. 18, with bypass diode 44 shown adjacent and connected to combined switch 54.

Manufacturing Embodiments of the present disclosure will be described in the context of a method 68 for manufacturing a solar cell 14, solar cell panel 10a, and/or satellite, including steps 70-82 shown in FIG. A satellite 84 having a solar cell panel 10a consisting of cells 14 is shown in FIG.

As shown in FIG. 19, in the pre-manufacturing stage, the example method 68 may include the specification and design 70 of the solar cells 14, solar cell panels 10a, and/or satellites 84, and the procurement 72 of their materials. The manufacturing stage includes manufacturing 74 and system integration 76 of solar cells 14, solar cell panels 10a, and/or satellite 84 components and subassemblies, which include solar cells 14, solar cell panels 10a, and /or including the manufacture of artificial satellites 84. Thereafter, solar cells 14, solar cell panels 10a, and/or satellites 84 may undergo certification and delivery 78 for service 80. Solar cells 14, solar cell panels 10a, and/or satellites 84 may also be scheduled for maintenance and maintenance 82 (including modifications, reconfigurations, refurbishments, etc.) prior to launch.

Each step of method 68 may be performed or performed by a system integrator, a third party, and/or an operator (eg, a customer). For purposes herein, a system integrator may include, but is not limited to, any number of manufacturers and primary system subcontractors of solar cells, solar cell panels, satellites or spacecraft; The operators may include, but are not limited to, any number of vendors, subcontractors, and suppliers, and the operators may be satellite communications companies, military organizations, service organizations, and the like.

As shown in FIG. 20, a satellite 84 manufactured by example method 68 may include a system 86, a body 88, a solar cell panel 10a comprised of solar cells 14, and one or more antennas 90. Examples of systems 86 included in satellite 84 include, but are not limited to, one or more of propulsion system 92 , electrical system 94 , communication system 96 , and power system 98 . Any number of other systems 86 may also be included.

FIG. 22 is an illustration of a solar cell panel 10a in the form of a functional block diagram, according to one embodiment. Solar cell panel 10a consists of a solar cell array 22 consisting of one or more of solar cells 14 individually attached to substrate 12. Each solar cell 14 absorbs light 100 from light source 102 and generates electrical output 104 in response.

At least one of the solar cells 14 has at least one cropped corner 24 that defines a corner region 26 such that an area 28 of the substrate 12 is provided with the solar cell 14 attached to the substrate 12. Sometimes it remains exposed. When multiple solar cells 14 are attached to substrate 12, corner regions 26 of adjacent solar cells 14 are aligned, thereby exposing areas 28 of substrate 12.

The areas 28 of the substrate 12 that remain exposed include one or more corner conductors 20 that are attached to, printed on, or incorporated into the substrate 12 and are connected to the solar cell 14. One or more electrical connections with the corner conductor 20 are made within a corner region 26 created by a cropped corner 24 of at least one of the solar cells 14 .

The corner area 26 resulting from the trimmed corner 24 has at least one contact point, for example a front surface contact 32 on the front side of the solar cell 14 and a /or includes a back contact 34 on the back side of the solar cell 14; The electrical connections include up/down or left/right series connections that determine the flow of power through the solar cell 14 and may include one or more bypass diodes 44.

Areas 28 of substrate 12 that remain exposed include corner areas 26 defined by cropped corners 24 adjacent solar cells 14 to alter the current flow path between solar cells 14 and electrical connections. at least one switch 54 located within. Substrate 12 includes one or more traces connected to switches 54 to make electrical connections between solar cells 14 .

Switch 54a reconfigures the string length for the electrical connection between solar cell 14 and switch 54b to bypass solar cell 14 in response to a control signal. Switch 54a also reconfigures connections between strings, allowing series connections between strings and reconfigurability of outputs. The switch 54 may be a single-pole single-throw (SPST) switch, a dual-pole single-throw (DPST) switch, or a function of the bypass diode 44. It may also be an integrated device that can be packaged to include functionality other than switching functionality, such as switching functionality.

Experimental Results To demonstrate the reconfiguration of the string length of the array, we constructed a solar cell array using a flex circuit board based on a corner conductor design.

FIG. 22A is an image of a demonstration solar cell array consisting of 12 solar cells arranged in three tiers, with four solar cells in each tier. Electrical connections are made within the corner regions to provide either series connections or string terminations. Current flow or conductive paths were 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 in some locations.

FIG. 22B is an image showing an enlarged view of one of the corner regions showing electrical connections between the front contact, the back contact, the bypass diode, and the solar cell.

FIG. 22C is a version of FIG. 22B with electrical connections between the top left and bottom left solar cells indicated by dark lines drawn on the conductive paths. One conductive path connects the back contact of the top left solar cell to the front contact of the bottom left solar cell, allowing current to flow downward. Another conductive path connects the back contact of the lower left solar cell through a bypass diode.

The electrical connection between the upper right solar cell and the lower right solar cell is rotated 180 degrees compared to the electrical connection between the upper left solar cell and the lower left solar cell, so that Current flows from the lower right solar cell to the upper right solar cell.

Jumpers are placed for series connection. By changing the position of the jumper, the current flow can be terminated within the buried trace.

FIG. 22D is an image of another corner region with wires added in place of jumpers. The wires could be shorted together and act like a jumper, or the wires could be separated and act like there is no jumper.

This demonstration uses jumpers or wires to configure a solar cell array with 12 solar cells from 2 strings with 6 solar cells to 3 strings with 4 solar cells. can be changed to .

FIG. 22E is a graph of photocurrent-voltage (LIV) measurements of solar cell arrays under AM0 (air mass coefficient for zero atmosphere) illumination; A three-string configuration with solar cells was used. Changes in voltage confirm changes in string length.

FIG. 22F is an image of the demonstration solar cell array of FIG. 22A, with the central four solar cells covered to prevent their operation.

FIG. 22G is a graph of LIV measurements of a solar cell array under AM0 illumination, with measurements made for the configuration shown in FIG. 22F with the central four solar cells covered to prevent their operation. Ta. Covering a solar cell is an experimental method to simulate damage to a solar cell that causes the solar cell to have reduced current or voltage output.

In this example, the solar cell array is configured to have three strings of four solar cells each. Data is shown for strings 1, 2, 3 both covered and uncovered. When uncovered, the three strings have similar outputs with voltages close to 11V. When covered, two strings lose solar cells and one string loses two solar cells. This solar cell loss is reflected in the voltage loss. The Vload vertical line represents the load voltage at which current is collected by the power system. With this load voltage selection, the load current will drop to approximately zero.

FIG. 22H is a graph of LIV measurements of a solar cell array under AM0 illumination, with measurements made for the configuration shown in FIG. 22F with the central four solar cells covered to prevent their operation. Ta.

In this example, the solar cell array is configured to have two strings of six solar cells each, and the six solar cells increase the power output of the string. There are four operating solar cells and two non-operating cells in each string, with the central four solar cells covered to prevent their operation. Current must flow through the bypass diodes of the non-operating solar cells, so the voltage output of the string is the four operating solar cells minus the two bypass diodes.

The data in Figure 22H shows the data for the original string before the middle four solar cells were covered. Then, when the four central solar cells are covered, the voltage drops to the level indicated by the damaged string.

Reconfiguring to a string length of six solar cells increases the voltage and power output of resilient strings 1 and 2. Similar to FIG. 22G, the Vload vertical line represents the load voltage. In the case of elastic strings 1 and 2, the load current is now approximately the same as in the original string.

Power from the four central covered solar cells is of course still lost. However, in a conventional solar cell array, damage to 4 out of 12 solar cells would significantly remove the current at the load supplied to the power system. In this example, by reconfiguring the solar cell array, power from each solar cell can be delivered to the power system with near-optimal collection. Specifically, the original string delivered 2.2 watts per solar cell at load voltage, but once the middle four solar cells were covered, the damaged string dropped to 0.1 watts per solar cell. do. After reconfiguration, elastic strings 1 and 2 can deliver 2.1 watts per functioning solar cell.

Power output could be improved by adding another switch connecting the front and back contacts of the solar cells in the array. By doing this, current will be diverted through the non-functioning solar cells in the array through a switch with no power loss. However, the solar cell array in this demonstration does not provide this functionality and therefore there is power loss into the bypass diode.

Additionally, this disclosure includes embodiments according to the following provisions.
Clause 1. includes one or more solar cells attached to a substrate, the substrate includes one or more electrical connections to the solar cells, and the substrate includes one or more electrical connections to the one or more of the solar cells. A solar cell array including one or more switches for bypassing one or more.
Clause 2. When at least one of the solar cells having one or more cropped corners is attached to a substrate, an area of the substrate remains exposed, and an area of the substrate that remains exposed is attached to at least one of the switches. A solar cell array according to clause 1, comprising:
Clause 3. at least one of the solar cells is attached to the substrate such that a corner area defined by a pruned corner of an adjacent one of the solar cells is aligned, thereby exposing an area of the substrate; Solar cell array according to clause 2.
Clause 4. 4. The solar cell array of clause 3, wherein at least one of the switches is located within a corner region defined by a pruned corner adjacent to at least one of the solar cells.
Clause 5. 5. A solar cell array according to any one of clauses 1 to 4, wherein the switch diverts current away from one or more of the solar cells.
Clause 6. 6. A solar cell array according to any one of clauses 1 to 5, wherein the solar cells, one or more bypass diodes, and the switch are electrically in parallel.
Clause 7. 7. Solar cell array according to any one of clauses 1 to 6, wherein the switch is controlled by one or more control signals.
Clause 8. Any one of clauses 1 to 7, wherein the switch, when closed, connects the front contact and the back contact of one or more of the solar cells, such that the current is diverted away from the one or more of the solar cells. Solar cell array described in.
Clause 9. 9. A solar cell array according to any one of clauses 1 to 8, further comprising one or more switches for adding or removing one or more of the solar cells from the string of solar cells.
Clause 10. Solar cell array according to clause 9, wherein the length of the strings is varied to vary the voltage produced by the strings.
Clause 11. 11. A solar cell array according to any one of clauses 1 to 10, wherein the electrical connections include one or more conductors on or in the substrate.
Clause 12. 12. A solar cell array according to any one of clauses 1 to 11, wherein the substrate includes one or more traces connected to a diversion switch for making electrical connections between solar cells.
Clause 13. attaching one or more solar cells to a substrate, the substrate including one or more electrical connections to the solar cells, and the substrate including one or more electrical connections to the one or more of the solar cells; A method for manufacturing a solar cell array comprising one or more switches for bypassing one or more.
Clause 14. When at least one of the solar cells having one or more pruned corners is attached to a substrate, an area of the substrate remains exposed, and an area of the substrate that remains exposed is attached to at least one of the switches. A method according to clause 13, including one.
Clause 15. at least one of the solar cells is attached to the substrate such that a corner area defined by a pruned corner of an adjacent one of the solar cells is aligned, thereby exposing an area of the substrate; The method described in Article 14.
Clause 16. 16. The method of clause 15, wherein at least one of the switches is located within a corner region defined by a pruned corner adjacent to at least one of the solar cells.
Clause 17. 17. A method according to any one of clauses 13 to 16, wherein the switch diverts the current away from one or more of the solar cells.
Article 18. 18. A method according to any one of clauses 13 to 17, wherein the solar cell, one or more bypass diodes and the switch are electrically in parallel.
Article 19. 19. A method according to any one of clauses 13 to 18, wherein the switch is controlled by one or more control signals.
Article 20. Any one of clauses 13 to 19, wherein the switch, when closed, connects the front contact and the back contact of one or more of the solar cells, such that the current is diverted away from one or more of the solar cells. The method described in.
Clause 21. Any one of clauses 13 to 20 further comprising adding or removing one or more of the solar cells from the string of solar cells using one or more switches. Method described.
Clause 22. 22. The method of clause 21, wherein the length of the string is varied to change the voltage produced by the string.
Clause 23. 23. A method according to any one of clauses 13 to 22, wherein the electrical connection comprises one or more conductors on or in the substrate.
Article 24. 24. A method according to any one of clauses 13 to 23, wherein the substrate comprises one or more traces connected to a diversion switch for making electrical connections between solar cells.
Article 25. controlling one or more switches in the one or more electrical connections to the one or more solar cells to bypass one or more of the electrical connections to one or more of the solar cells; A method of operating a solar cell array, including.

Conclusion The above description of embodiments has been presented for purposes of illustration and description, and is not intended to be exhaustive or to limit the embodiments described. Many alternatives, modifications, and variations may be used in place of the specific elements described above.

Claims (25)

comprising one or more solar cells (14) attached to a substrate (12);
the substrate includes one or more electrical connections to the solar cell;
A solar cell array, wherein the substrate includes one or more switches (54) for bypassing one or more of the electrical connections to one or more of the solar cells. When at least one of said solar cells (14) having one or more pruned corners (24) is attached to said substrate, an area (28) of said substrate (12) remains exposed;
The solar cell array of claim 1, wherein the area of the substrate that remains exposed includes at least one of the switches (54a) (54b). The corner areas (26) defined by the trimmed corners (24) of the at least one adjacent one of the solar cells (14) are aligned, thereby aligning the area (28) of the substrate (12). 3. A solar cell array according to claim 2, wherein the at least one of the solar cells (14) is attached to the substrate (12) so as to expose the solar cell (14). wherein said at least one of said switches (54) is located within said corner area (26) defined by said pruned corner (24) adjacent said at least one of said solar cells. The solar cell array according to item 3. 5. A solar cell array according to any preceding claim, wherein the switch (54) diverts current away from one or more of the solar cells. 6. A solar cell array according to any preceding claim, wherein the solar cell, one or more bypass diodes (44) and the switch are electrically in parallel. A solar cell array according to any preceding claim, wherein the switch (54) is controlled by one or more control signals. The switch (54), when closed, connects the front contact (32) and back contact (34) of the one or more of the solar cells (14) such that current flows between the front contact (32) and the back contact (34) of the one or more of the solar cells (14). The solar cell array according to any one of claims 1 to 7, wherein the solar cell array avoids or detours from a plurality of solar cell arrays. Any one of claims 1 to 8, further comprising one or more switches (54) for adding or removing one or more of the solar cells to or from the string of solar cells. Solar cell array described in. 10. The solar cell array of claim 9, wherein the length of the strings is varied to vary the voltage produced by the strings. A solar cell array according to any preceding claim, wherein the electrical connections include one or more conductors (20) on or in the substrate (12). Any one of claims 1 to 11, wherein the substrate (12) comprises one or more traces connected to a bypass switch (54b) for making the electrical connection between the solar cells (14). Solar cell array described in. A method of operating a solar cell array, the method comprising:
one or more of the one or more electrical connections to the one or more solar cells (14) for bypassing one or more of the electrical connections to one or more of the solar cells; A method comprising controlling a switch (54). A method for manufacturing a solar cell array, the method comprising:
attaching one or more solar cells (14) to a substrate (12);
the substrate includes one or more electrical connections to the solar cell;
The method, wherein the substrate includes one or more switches (54) for bypassing one or more of the electrical connections to one or more of the solar cells. When at least one of said solar cells (14) having one or more pruned corners (24) is attached to said substrate, an area (28) of said substrate (12) remains exposed;
15. The method of claim 14, wherein the area of the substrate that remains exposed includes at least one of the switches (54). corner areas (26) defined by the trimmed corners (24) of the at least one adjacent of the solar cells (14) are aligned, thereby exposing the area (28) of the substrate; 16. The method of claim 15, wherein said at least one of said solar cells (14) is attached to said substrate (12) so as to. The at least one of the switches (54) is located within the corner area (26) defined by the cropped corner (24) adjacent to the at least one of the solar cells (14). 17. The method of claim 16. 18. A method according to any one of claims 14 to 17, wherein the switch (54) diverts current away from one or more of the solar cells (14). 19. A method according to any one of claims 14 to 18, wherein the solar cell (14), one or more bypass diodes (44) and the switch (54) are electrically in parallel. 20. A method according to any one of claims 14 to 19, wherein the switch (54) is controlled by one or more control signals. The switch (54), when closed, connects the front and back contacts of the one or more of the solar cells (14) so that current is diverted away from the one or more of the solar cells. 21. A method according to any one of claims 14 to 20. Claim further comprising adding or removing one or more of the solar cells (14) from the string of solar cells using one or more switches (54). The method according to any one of Items 14 to 21. 23. The method of claim 22, wherein the length of the string is varied to vary the voltage produced by the string. 24. A method according to any one of claims 14 to 23, wherein the electrical connection comprises one or more conductors (20) on or in the substrate (12). 25. Any one of claims 14 to 24, wherein the substrate (12) comprises one or more traces connected to a bypass switch (54b) for making the electrical connection between the solar cells (14). The method described in.

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