Back contact solar cell module

Abstract

The application discloses a back contact solar cell module, which comprises a plurality of back contact solar cells arranged along a first direction, the back contact solar cells having main grids extending along a second direction and thin grids extending along the first direction, the width of the main grids being greater than the width of the thin grids, and the first direction being perpendicular to the second direction; and interconnecting wires extending along the first direction and connecting adjacent back contact solar cells in series. The interconnecting wires are perpendicular to the main grids. The number of the interconnecting wires and the number of the main grids do not need to be consistent, so that when the number of the main grids of the cells changes, a substantial modification of the welding equipment at the module end is not needed, and the compatibility of the welding equipment is improved. In addition, the optimal design of the cell efficiency and the optimal design of the power at the module end can be achieved simultaneously. The scheme of the application connects the interconnecting wires through the main grids, alleviates the mismatch of the local area of the cells caused by the non-uniformity of the local current or voltage, and is beneficial to reducing the power loss.

Description

Technical Field

[0001] This utility model relates to the field of photovoltaic technology, specifically to a back-contact solar cell module. Background Technology

[0002] In related technologies, the surface of a solar cell has mutually perpendicular main grids and fine grids. The densely distributed fine grids collect photogenerated current, which is then converged to the main grids and transmitted to the outside of the solar cell via interconnecting wires connected to the main grids. The main grids are wider than the fine grids to carry a larger current.

[0003] The positive main grid, positive fine grid, negative main grid, and negative fine grid of a back-contact solar cell are all located on the back side. Within a back-contact solar cell module, multiple back-contact solar cells are arranged in a row and electrically connected in series to form a cell string. The interconnecting wires extend in the same direction as the main grid, are superimposed on it, and are electrically connected to the main grid.

[0004] The number of interconnect wires in existing back-contact solar cell modules must be consistent with the number of main busbars. When the number of main busbars changes, it necessitates a significant modification to the interconnect wire welding equipment used in module manufacturing; this costly equipment modification is commonplace. Furthermore, the choice of interconnect wire number depends on the number of main busbars, making it impossible to simultaneously achieve optimal cell efficiency and optimal module power design; compromise solutions are often preferred. Utility Model Content

[0005] To address at least one technical problem of the prior art, this disclosure provides a back-contact solar cell module.

[0006] According to some embodiments of the present disclosure, a back-contact solar cell module includes: a plurality of back-contact solar cells arranged along a first direction, each back-contact solar cell having a main grid extending along a second direction and a fine grid extending along the first direction, the width of the main grid being greater than the width of the fine grid, the first direction being perpendicular to the second direction; and interconnecting wires extending along the first direction to connect adjacent back-contact solar cells in series.

[0007] In some embodiments, the main grid includes a first main grid and a second main grid that are alternately arranged in a first direction and have different polarities, and the interconnecting wires include a first interconnecting wire and a second interconnecting wire that are alternately arranged in a second direction. The first main grid and the second main grid that are in back contact with the solar cell are electrically connected to the interconnecting wires, and then electrically connected to the second main grid and the first main grid of another solar cell through the interconnecting wires.

[0008] In some embodiments, a first back-contact solar cell, a second back-contact solar cell, and a third back-contact solar cell are arranged sequentially along a first direction. One side of a first interconnecting wire is conductively connected to the first main grid of the second back-contact solar cell, and the other side is conductively connected to the second main grid of the first back-contact solar cell. One side of a second interconnecting wire is conductively connected to the second main grid of the second back-contact solar cell, and the other side is conductively connected to the first main grid of the third back-contact solar cell.

[0009] In some embodiments, the back side of the back contact solar cell also has a first grid and a second grid. The first grid extends parallel to each other in a first direction between adjacent first and second main grids and is spaced apart in a second direction. The ends of the first grid are spaced apart from the second main grids. The second grid extends parallel to each other in the first direction between adjacent first and second main grids and is spaced apart in a second direction. The ends of the second grid are spaced apart from the first main grids. The first grid and the second grid are alternately arranged between adjacent first and second main grids in the second direction.

[0010] In some embodiments, each first main gate and each second main gate are respectively connected to a plurality of pads spaced apart in a second direction. The width of the pads in the first direction is greater than the width of the first main gate and the second main gate. Interconnect wires are physically and electrically connected to the pads, and then electrically connected to the first main gate and the second main gate.

[0011] In some embodiments, the back-contact solar cells are arranged along a first direction, and the first and second main grids both extend along a second direction, with the pads of adjacent back-contact solar cells having opposite polarities aligned.

[0012] In some embodiments, on the back side of the back-contact solar cell, a first insulating layer is provided along the extension path of the first interconnecting wire, the first insulating layer electrically isolating the second main grid from the first interconnecting wire, and a second insulating layer is provided along the extension path of the second interconnecting wire, the second insulating layer electrically isolating the first main grid from the second interconnecting wire.

[0013] In some embodiments, the width of the first insulating layer and / or the second insulating layer in the second direction is 1-10 mm.

[0014] In some embodiments, the first insulating layer also electrically isolates the second fine gate from the first interconnecting wire, and the second insulating layer also electrically isolates the first fine gate from the second interconnecting wire.

[0015] In some implementations, the spacing between the first main gate and the second main gate is 2-30 mm.

[0016] In some implementations, the spacing between adjacent first interconnecting wires and second interconnecting wires on each back-contact solar cell does not exceed 20 mm.

[0017] The interconnecting wires disclosed herein are perpendicular to the main busbars. The number of interconnecting wires and the number of main busbars do not need to be consistent; therefore, when the number of cell main busbars changes, there is no need for significant simultaneous modifications to the module-side welding equipment, improving the compatibility of the welding equipment. Furthermore, optimal cell efficiency design and optimal module power design can be achieved simultaneously.

[0018] The inventors were also pleasantly surprised to find that the interconnecting wires of the disclosed solution are connected through the main grid, which alleviates the mismatch in local areas of the battery caused by uneven local current or voltage, and is beneficial to reducing power loss. Attached Figure Description

[0019] To more clearly illustrate the specific embodiments of this utility model or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0020] Figure 1 A rear view of a back-contact solar cell in the prior art is shown.

[0021] Figure 2 A rear view of a battery string in a prior art back-contact solar cell module is shown.

[0022] Figure 3 The rear view of a battery string of a back-contact solar cell module, as shown in some examples of this disclosure, is illustrated.

[0023] Figure 4 The rear view of a battery in a back-contact solar cell module, as shown in this disclosure, is illustrated in some examples.

[0024] Figure 5 The rear view of the battery of a back-contact solar cell module is shown in some other examples of this disclosure.

[0025] Figure 6 A rear view of the battery arrangement of a battery string of a back-contact solar cell module, as shown in some examples of this disclosure, is illustrated. Detailed Implementation

[0026] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort should fall within the scope of protection of the present application.

[0027] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0028] Figure 1 A rear view of an existing back-contact battery is shown. Figure 1 As shown, the positive electrode includes a positive electrode main grid 111 and a positive electrode fine grid 112, and the negative electrode includes a negative electrode main grid 121 and a negative electrode fine grid 122. The positive electrode main grid 111 and the negative electrode main grid 121 extend along a first direction D1 and are alternately arranged in a second direction D2. The positive electrode fine grid 112 and the negative electrode fine grid 122 extend along the second direction D2 and are alternately arranged in the first direction D1. The first direction D1 and the second direction D2 are two mutually perpendicular directions. Therefore, the positive and negative electrodes are arranged like interlaced fingers, hence the back contact solar cell is also called an interdigitated back contact (IBC) solar cell. To prevent the positive electrode fine grid 112 from overlapping with the negative electrode main grid 121 and the negative electrode fine grid 122 from overlapping with the positive electrode main grid 111, causing an internal short circuit in the solar cell, the positive electrode fine grid 112 is spaced apart at the negative electrode main grid 121, and the negative electrode fine grid 122 is also spaced apart at the positive electrode main grid 111.

[0029] Figure 2 A string of cells in a conventional back-contact solar cell module is shown. In a back-contact cell string, back-contact cells can be interconnected via solder ribbons 200. A common practice in the art is to stack the solder ribbons 200 along a first direction D1 on the main grid, with multiple solar cells arranged along the first direction D1. The positive electrode main grid, the negative electrode main grid, and the solder ribbons all extend along the first direction D1. A portion of the solder ribbon is electrically connected to the positive electrode main grid of the solar cell, and another portion of the solder ribbon is electrically connected to the negative electrode main grid of the adjacent solar cell.

[0030] The main busbar, also known as the busbar, is abbreviated as BB. In the history of solar cell development, to optimize carrier collection and balance optical and electrical losses, the number of busbars has evolved from early 2BB, 3BB, and 4BB to later MBB (Multi-Busbar) and then SMBB (SuperMulti-Busbar). Regardless of the number of main busbars, the solder ribbon and the main busbar have always been parallel and superimposed on the main busbar; this has become a fixed mindset in the field. Each generation of products has seen changes in the number of main busbars accompanied by an increase in the number of solder ribbons and a corresponding modification to the soldering equipment.

[0031] According to one aspect of this disclosure, a back-contact solar cell module is provided in which the solder strips and main busbars are arranged to intersect each other, so that the number of solder strips does not need to be adjusted when the number of main busbars changes.

[0032] Figure 3 A back-contact solar cell assembly according to an example embodiment of this disclosure is shown. More specifically, Figure 3 A back-contact solar cell module comprising three adjacent back-contact solar cells 20 having a rectangular plate shape, being arranged substantially on the same plane, aligned along a first direction D1 and connected to each other. Figure 4 and Figure 5 The back views of back-contact solar cells with different example embodiments are shown respectively.

[0033] like Figure 3 As shown, the back-contact solar cell module includes multiple back-contact solar cells 20 arranged along a first direction D1 and interconnecting wires 30 extending along the first direction D1 and connecting these back-contact solar cells 20 in series. Each back-contact solar cell 20 includes a main grid extending along a second direction D2 and a fine grid extending along the first direction D1. The width of the main grid is greater than the width of the fine grid, allowing current collected by the fine grid to be channeled to the main grid for transmission. The width of the fine grid can be 10-50 μm.

[0034] In the exemplary embodiments of this disclosure, the interconnecting wires 30 are perpendicular to the main grid. The number of interconnecting wires 30 and the number of main grids do not need to be consistent; therefore, when the number of main grids changes, there is no need for significant modifications to the module-side welding equipment, improving the compatibility of the welding equipment. Furthermore, optimal design for cell efficiency and optimal design for module power can be achieved simultaneously. Surprisingly, the interconnecting wires 30 are connected via the main grids, reducing mismatch in localized areas of the cell caused by uneven current or voltage, thus reducing power loss.

[0035] like Figure 3As shown, the back-contact solar cell 20 includes a first main grid 21 and a second main grid 22 with different conductivity types. The first main grid 21 and the second main grid 22 are formed on the back side of the back-contact solar cell 20, respectively collecting and transporting electrons and holes. Specifically, as... Figure 3 As shown, the first main gate 21 and the second main gate 22 extend parallel to each other in the second direction D2 and are alternately arranged in the first direction D1, wherein the first direction D1 and the second direction D2 are two mutually perpendicular directions. For example, the first main gate 21 extends parallel to each other along the second direction D2 and is spaced apart in the first direction D1. The second main gate 22 extends parallel to each other along the second direction D2 and is spaced apart in the first direction D1. The first main gate 21 and the second main gate 22 are alternately arranged in the first direction D1 and are spaced apart from each other by a uniform distance.

[0036] For example, the spacing between adjacent first main gate 21 and second main gate 22 is 2-30 mm. If the spacing between adjacent first main gate 21 and second main gate 22 is too small, the main gates will be too dense, which will increase the unit loss of conductive paste, while if the spacing is too large, it will increase the distance that the fine gate current is transmitted to the main gate, thereby increasing the transmission loss.

[0037] The back-contact solar cell 20 also includes a first fine grid 23 with the same conductivity type as the first main grid 21 and a second fine grid 24 with the same conductivity type as the second main grid 22. Please refer to... Figure 4 A first fine grid 23 and a second fine grid 24 are formed on the back side of the back-contact solar cell 20, respectively connected to the first main grid 21 and the second main grid 22, and respectively collecting electrons and holes. The first fine grid 23 extends parallel to each other along a first direction D1 between adjacent first main grids 21 and second main grids 22, and is spaced apart along a second direction D2, with the ends of the first fine grid 23 spaced apart from the second main grid 22. The second fine grid 24 extends parallel to each other along the first direction D1 between adjacent first main grids 21 and second main grids 22, and is spaced apart along a second direction D2, with the ends of the second fine grid 24 spaced apart from the first main grid 21. The first fine grid 23 and the second fine grid 24 between adjacent first main grids 21 and second main grids 22 are alternately arranged along the second direction D2, spaced at a uniform distance.

[0038] In some example embodiments, each first main gate 21 and each second main gate 22 are respectively connected to a plurality of pads spaced apart in a second direction D2. The width of the pads in the first direction D1 is greater than the width of the first main gate 21 and the second main gate 22. The interconnecting wires 20 are designed to be physically and electrically connected to the pads, and thus electrically connected to the first main gate 21 and the second main gate 22.

[0039] Specifically, such as Figure 4As shown, the pads include a first pad 211 electrically connected to the first main gate 21 and a second pad 221 electrically connected to the second main gate 22. The first pad 211 and the second pad 221 are offset from each other along a first direction D1, such that the interconnecting wires 30 connecting the first pad 211 and the interconnecting wires 30 connecting the second pad 221 can be spaced apart from each other in a second direction D2.

[0040] More specifically, the back-contact solar cells 20 are arranged along a first direction D1, and the first main grid 21 and the second main grid 22 both extend along a second direction D2. The pads of adjacent back-contact solar cells with opposite polarities are aligned. For example, please refer to... Figure 6 Taking the second back contact solar cell 20b as an example, the first pad 211 of the second back contact solar cell 20b is aligned with the second pad 221 of the adjacent first back contact solar cell 20a and third back contact solar cell 20c, and the second pad 221 of the second back contact solar cell 20b is aligned with the first pad 211 of the adjacent first back contact solar cell 20a and third back contact solar cell 20c.

[0041] In some embodiments, such as Figure 5 As shown, the back-contact solar cell 20 may include a first main grid 21, a second main grid 22, a first fine grid 23, and a second fine grid 24, but does not include pads. Interconnect wires 30 may be directly physically and electrically connected to the main grid.

[0042] Interconnecting wires 30 connect adjacent back-contact solar cells in series. Interconnecting wires 30 extend along a first direction D1 and are spaced apart along a second direction D2. Specifically, the first main grid 21 and the second main grid 22 of the back-contact solar cell are electrically connected to the interconnecting wires 30, and thus electrically connected to the second main grid 22 and the first main grid 21 of another back-contact solar cell.

[0043] More specifically, Figure 3 The back-contact solar cell string shown includes a first back-contact solar cell 20a, a second back-contact solar cell 20b, and a third back-contact solar cell 20c, which are arranged sequentially in the first direction D1. Taking the middle second back-contact solar cell 20b as an example, the interconnecting wires 30 include a first interconnecting wire 31 and a second interconnecting wire 32, which extend along the first direction D1 and are alternately spaced apart in the second direction D2. One side of the first interconnecting wire 31 is electrically connected to the first main grid 21 of the second back-contact solar cell 20b, and the other side is electrically connected to the second main grid 22 of the first back-contact solar cell 20a. One side of the second interconnecting wire 32 is electrically connected to the second main grid 22 of the second back-contact solar cell 20b, and the other side is electrically connected to the first main grid 21 of the third back-contact solar cell 20c, thereby connecting the first back-contact solar cell 20a, the second back-contact solar cell 20b, and the third back-contact solar cell 20c in series.

[0044] For example, the spacing between adjacent first interconnecting wires 31 and second interconnecting wires 32 on each back-contact solar cell does not exceed 20 mm. Excessive spacing between adjacent interconnecting wires would result in overly sparse interconnecting wire arrangement, thereby increasing current transmission losses in the main grid.

[0045] More specifically, in some examples, for a back-contact solar cell with pads, taking the second back-contact solar cell 20b as an example, the first interconnecting wire 31 is physically and electrically connected to the first pads 211 of the second back-contact solar cell 20b arranged along the first direction D1, extends along the first direction D1 to the adjacent first back-contact solar cell 20a and is physically and electrically connected to the second pads 221 of the first back-contact solar cell 20a, thereby connecting the second back-contact solar cell 20b and the first back-contact solar cell 20a in series. The second interconnecting wire 32 is physically and electrically connected to the second pads 221 of the second back-contact solar cell 20b arranged along the first direction D1, extends along the first direction D1 to the adjacent third back-contact solar cell 20c and is physically and electrically connected to the second pads 221 of the third back-contact solar cell 20c.

[0046] Interconnecting wires 30 are isolated from the main grid and fine grids of opposite polarity by an insulating layer 40. For example, please refer to... Figure 6 On the back side of the back-contact solar cell 20, a first insulating layer 41 is provided along the extension path of the interconnecting wire 30 (e.g., the first interconnecting wire 31) electrically connected to the first main grid 21. This first insulating layer 41 at least electrically isolates the second main grid 22 from the interconnecting wire 30. Similarly, a second insulating layer 42 is provided along the extension path of the interconnecting wire 30 (e.g., the second interconnecting wire 32) electrically connected to the second main grid 22. This second insulating layer 42 at least electrically isolates the first main grid 21 from the interconnecting wire 30. The insulating layers prevent short circuits in the back-contact solar cell caused by contact between conductors of different polarities. The insulating layer can be an electrically insulating material with one or more of the following as its main components: epoxy resin, silicone resin, polyurethane, or acrylic resin.

[0047] In some embodiments, the first insulating layer 41 extends continuously between the first main gates 21 and also electrically isolates the first interconnecting wire 31 from the second fine gate 24. The second insulating layer 42 extends continuously between the second main gates 22 and also electrically isolates the second interconnecting wire 32 from the first fine gate 23.

[0048] Of course, in some other embodiments, if the fine grids are sparsely arranged, that is, the first fine grid 23 and the second fine grid 24 are arranged with a certain large spacing, then it is not necessary to electrically isolate the first interconnecting wire 31 from the second fine grid 24 and the second interconnecting wire 32 from the first fine grid 23. In other words, the first insulating layer 23 and the second insulating layer 24 can respectively only cover the second main grid 22 and the first main grid 21, which can save the amount of insulating material.

[0049] In some embodiments, the width of the first insulating layer and / or the second insulating layer in the second direction is 1-10 mm. The minimum width of the insulating layer is not less than 1 mm, which reduces the alignment requirements of the interconnecting wires and helps improve the reliability of the back-contact solar cell module. Of course, an excessively wide insulating layer will increase the consumption of insulating layer material.

[0050] Finally, it should be noted that the above are merely preferred embodiments of the present utility model and are not intended to limit the present utility model. Although the present utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A back-contact solar cell module, characterized in that, include: Multiple back-contact solar cells are arranged along a first direction. Each back-contact solar cell has a main grid extending along a second direction and a fine grid extending along the first direction. The width of the main grid is greater than the width of the fine grid. The first direction is perpendicular to the second direction. as well as Interconnecting wires, extending along the first direction, connect adjacent back-contact solar cells in series.

2. The back-contact solar cell module according to claim 1, characterized in that, The main grid includes a first main grid and a second main grid that are alternately arranged in the first direction and have different polarities. The interconnecting wires include a first interconnecting wire and a second interconnecting wire that are alternately arranged in the second direction. The first main grid and the second main grid of the back contact solar cell are respectively electrically connected to the interconnecting wires, and then electrically connected to the second main grid and the first main grid of another back contact solar cell through the interconnecting wires.

3. The back-contact solar cell module according to claim 2, characterized in that, The device includes a first back-contact solar cell, a second back-contact solar cell, and a third back-contact solar cell arranged sequentially along the first direction. One side of the first interconnecting wire is conductively connected to the first main grid of the second back-contact solar cell, and the other side is conductively connected to the second main grid of the first back-contact solar cell. One side of the second interconnecting wire is conductively connected to the second main grid of the second back-contact solar cell, and the other side is conductively connected to the first main grid of the third back-contact solar cell.

4. The back-contact solar cell module according to claim 2, characterized in that, The back side of the back contact solar cell also has a first grid and a second grid. The first grid extends parallel to each other along a first direction between adjacent first main grids and second main grids, and is spaced apart in a second direction. The ends of the first grid are spaced apart from the second main grids. The second grid extends parallel to each other along the first direction between adjacent first main grids and second main grids, and is spaced apart in the second direction. The ends of the second grid are spaced apart from the first main grids. The first grid and the second grid between adjacent first main grids and second main grids are alternately arranged in the second direction.

5. The back-contact solar cell module according to claim 2, characterized in that, Each of the first main gate and each of the second main gates are respectively connected to a plurality of pads spaced apart in the second direction. The width of the pads in the first direction is greater than the width of the first main gate and the second main gate. The interconnecting wires are physically and electrically connected to the pads, and thus electrically connected to the first main gate and the second main gate.

6. The back-contact solar cell module according to claim 5, characterized in that, The back-contact solar cells are arranged along the first direction, and the first main grid and the second main grid both extend along the second direction, with the pads of adjacent back-contact solar cells having opposite polarities aligned.

7. The back-contact solar cell module according to claim 4, characterized in that, On the back side of the back contact solar cell, a first insulating layer is provided on the extension path of the first interconnecting wire, the first insulating layer electrically isolating the second main grid from the first interconnecting wire, and a second insulating layer is provided on the extension path of the second interconnecting wire, the second insulating layer electrically isolating the first main grid from the second interconnecting wire.

8. The back-contact solar cell module according to claim 7, characterized in that, The width of the first insulating layer and / or the second insulating layer in the second direction is 1-10 mm.

9. The back-contact solar cell module according to claim 7 or 8, characterized in that, The first insulating layer also electrically isolates the second fine gate from the first interconnecting wire, and the second insulating layer also electrically isolates the first fine gate from the second interconnecting wire.

10. The back-contact solar cell module according to claim 2, characterized in that, The spacing between adjacent first and second main gates is 2-30mm.

11. The back-contact solar cell module according to claim 2, characterized in that, The spacing between adjacent first interconnecting wires and second interconnecting wires on each of the back-contact solar cells shall not exceed 20 mm.

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