Back contact solar cell module

Abstract

The invention discloses a back contact solar cell module which comprises a plurality of back contact solar cells which are arranged in a first direction, each back contact solar cell is provided with a main grid extending in a second direction and a fine grid extending in the first direction, the width of the main grid is larger than that of the fine grid, and the first direction is perpendicular to the second direction; and the interconnection wires extend along the first direction and connect the adjacent back contact solar cells in series. And the interconnection lead is vertical to the main grid. The number of the interconnection wires and the number of the main grids do not need to be kept consistent, so that when the number of the main grids of the battery is changed, assembly end welding equipment does not need to be greatly transformed synchronously, and the compatibility of the welding equipment is improved. In addition, the optimal design of the battery efficiency and the optimal design of the module end power can be achieved at the same time. According to the scheme disclosed by the invention, the interconnection wires are connected through the main grids, so that the mismatch of the local area of the battery caused by non-uniform local current or voltage is relieved, and the method is beneficial to reducing the caused power loss.

Description

Technical Field

[0001] The present invention relates to the field of photovoltaic technology, in particular to a back-contact solar cell module. Background Art

[0002] In related technologies, the surface of a solar cell has a main grid and fine grids that are perpendicular to each other. The densely distributed fine grids collect the photocurrent, which is then channeled to the main grid and then transmitted to the outside of the solar cell via interconnecting wires connected to the main grid. The main grid is wider than the fine grids to transmit a higher current than the fine grids.

[0003] The positive busbar, positive fine grid, negative busbar, 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 by interconnecting wires to form a cell string. The interconnecting wires extend in the same direction as the busbars, superimposed on them, and are electrically connected to them.

[0004] Existing back-contact solar cell modules require the same number of interconnect wires as the number of busbars. Changing the number of busbars in a cell necessitates significant modifications to the interconnect wire welding equipment at the module manufacturing end, a costly upgrade that is commonplace. Furthermore, the choice of interconnect wire number depends on the number of busbars, making it difficult to achieve both optimal cell efficiency and optimal module power simultaneously. This often leads to compromises. Summary of the Invention

[0005] To solve at least one technical problem in the prior art, the present 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, the back-contact solar cells 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, and 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 with different polarities that are alternately arranged in a first direction, the interconnection wire includes a first interconnection wire and a second interconnection wire that are alternately arranged in a second direction, and the first main grid and the second main grid of the back-contact solar cell are respectively conductively connected to the interconnection wires, and then are respectively conductively connected to the second main grid and the first main grid of another back-contact solar cell through the interconnection wires.

[0008] In some embodiments, the first back-contact solar cell, the second back-contact solar cell, and the third back-contact solar cell are arranged in sequence along a first direction, one side of the first interconnection 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 interconnection 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 further has a first fine grid and a second fine grid, the first fine grids extending parallel to each other along the first direction between adjacent first main grids and second main grids, and arranged at intervals in the second direction, with the ends of the first fine grids spaced apart from the second main grids, the second fine grids extending parallel to each other along the first direction between adjacent first main grids and second main grids, and arranged at intervals in the second direction, with the ends of the second fine grids spaced apart from the first main grids, and the first fine grids and the second fine grids between adjacent first main grids and second main grids are alternately arranged 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 arranged at intervals 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, and the interconnecting wires are conductively connected to the first main gate and the second main gate through physical and electrical connections with the pads.

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

[0012] In some embodiments, on the back side of the back-contact solar cell, a first insulating layer is provided on the extension path of the first interconnection wire, and the first insulating layer at least electrically isolates the second main grid from the first interconnection wire. A second insulating layer is provided on the extension path of the second interconnection wire, and the second insulating layer at least electrically isolates the first main grid from the second interconnection 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 further electrically isolates the second fine gate from the first interconnection conductive line, and the second insulating layer further electrically isolates the first fine gate from the second interconnection conductive line.

[0015] In some embodiments, the spacing between the first busbar and the second busbar is 2-30 mm.

[0016] In some embodiments, the spacing between adjacent first interconnect wires and second interconnect wires on each back-contact solar cell is no more than 20 mm.

[0017] The interconnect wires in this disclosure are perpendicular to the busbars. The number of interconnect wires and busbars does not need to be consistent. Therefore, when the number of battery busbars changes, there is no need to significantly modify the module-side welding equipment, thereby improving the compatibility of welding equipment. Furthermore, optimal cell efficiency and module-side power can be achieved simultaneously.

[0018] The inventors were also surprised to find that the interconnected wires in the disclosed solution are connected through the main grid, which alleviates the mismatch of local areas of the battery caused by local current or voltage unevenness, and is beneficial to reducing power loss. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

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

[0021] Figure 2 FIG. 1 shows a back view of a cell string of a back-contact solar cell module in the prior art.

[0022] Figure 3 A back view of a cell string of a back-contact solar cell module according to some examples of the present disclosure is shown.

[0023] Figure 4 Shown are back views of cells of back-contact solar cell modules according to some examples of the present disclosure.

[0024] Figure 5 Shown are back views of cells of back-contact solar cell modules according to other examples of the present disclosure.

[0025] Figure 6 A back view of the cell arrangement of a cell string of a back-contact solar cell module according to some examples of the present disclosure is shown. DETAILED DESCRIPTION

[0026] In order to enable those skilled in the art to better understand the present invention, the following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of this application.

[0027] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments in this application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0028] Figure 1 FIG shows a back view of an existing back contact battery. Figure 1 As shown, the positive electrode includes a positive electrode busbar 111 and a positive electrode fine grid 112, and the negative electrode includes a negative electrode busbar 121 and a negative electrode fine grid 122. The positive electrode busbar 111 and the negative electrode busbar 121 extend along a first direction D1 and are arranged alternately in a second direction D2. The positive electrode fine grid 112 and the negative electrode fine grid 122 extend along a second direction D2 and are arranged alternately in the first direction D1, with the first direction D1 and the second direction D2 being perpendicular to each other. Therefore, the positive and negative electrodes are arranged like interdigitated fingers, and 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 the negative electrode busbar 121 and the negative electrode fine grid 122 from overlapping the positive electrode busbar 111, which could cause an internal short circuit in the solar cell, the positive electrode fine grid 112 is separated from the negative electrode busbar 121, and the negative electrode fine grid 122 is also separated from the positive electrode busbar 111.

[0029] Figure 2 The figure shows a cell string of a conventional back-contact solar cell module. In a back-contact cell string, the back-contact cells can be interconnected via a soldering ribbon 200. A common practice in the art is to superimpose the soldering ribbon 200 on the busbar along a first direction D1. Multiple solar cells are arranged along the first direction D1, with the positive and negative busbars, as well as the soldering ribbon, all extending along the first direction D1. A portion of the soldering ribbon is electrically connected to the positive busbar of the solar cell, while another portion is electrically connected to the negative busbar of an adjacent solar cell.

[0030] The main grid (also known as busbar, or BB for short) has evolved throughout the history of solar cell development, from 2BB, 3BB, and 4BB in the early days to MBB (Multi-Busbar) and then SMBB (Super Multi-Busbar) to optimize carrier collection and balance optical and electrical losses. Regardless of the number of busbars, the soldering ribbons are always parallel to and superimposed on the busbars, a principle that has become a fixed concept for those skilled in the art. Each generation of busbars is accompanied by an increase in the number of soldering ribbons and a simultaneous modification of the soldering equipment.

[0031] According to one aspect of the present disclosure, a back-contact solar cell module is provided, in which solder strips and bus bars are arranged to cross each other, and when the number of bus bars changes, the number of solder strips does not need to be adjusted.

[0032] Figure 3 A back contact solar cell assembly according to an exemplary embodiment of the present disclosure is shown. More specifically, Figure 3 A back-contact solar cell module is shown, which includes three adjacent back-contact solar cells 20 having a rectangular thin 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 figures show the back views of back-contact solar cells according to different exemplary embodiments.

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

[0034] In the exemplary embodiments of the present disclosure, interconnecting wires 30 are perpendicular to the busbars. The number of interconnecting wires 30 and the number of busbars do not need to be consistent. Therefore, when the number of battery busbars changes, there is no need to significantly modify the module-side welding equipment, thereby improving welding equipment compatibility. Furthermore, optimal design for battery efficiency and optimal design for module-side power can be achieved simultaneously. Surprisingly, the interconnecting wires 30 are connected through the busbars, reducing mismatches in localized battery regions caused by local current or voltage unevenness, thereby minimizing power losses.

[0035] like Figure 3As shown, the back contact solar cell 20 includes a first main grid 21 and a second main grid 22 of different conductive 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 to collect and transmit electrons and holes respectively. Figure 3 As shown, the first bus bars 21 and the second bus bars 22 extend parallel to each other in the second direction D2 and are alternately arranged in the first direction D1, where the first direction D1 and the second direction D2 are perpendicular to each other. For example, the first bus bars 21 extend parallel to each other along the second direction D2 and are spaced apart in the first direction D1. The second bus bars 22 extend parallel to each other along the second direction D2 and are spaced apart in the first direction D1. The first bus bars 21 and the second bus bars 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 busbars 21 and second busbars 22 is 2-30 mm. If the spacing between adjacent first busbars 21 and second busbars 22 is too small, the busbars will be too densely packed, which will increase the unit consumption of the conductive paste. However, if the spacing is too large, the distance that the fine grid current must travel to reach the busbar will be increased, resulting in increased transmission losses.

[0037] The back contact solar cell 20 further includes a first fine grid 23 of the same conductivity type as the first main grid 21 and a second fine grid 24 of the same conductivity type as the second main grid 22. Figure 4 The first fine grid 23 and the second fine grid 24 are formed on the back side of the back-contact solar cell 20, connected to the first busbar 21 and the second busbar 22, respectively, to collect electrons and holes. The first fine grids 23 extend parallel to each other along the first direction D1 between adjacent first busbars 21 and second busbars 22, and are arranged at intervals in the second direction D2. The ends of the first fine grids 23 are spaced apart from the second busbars 22. The second fine grids 24 extend parallel to each other along the first direction D1 between adjacent first busbars 21 and second busbars 22, and are arranged at intervals in the second direction D2. The ends of the second fine grids 24 are spaced apart from the first busbars 21. The first fine grids 23 and the second fine grids 24 between adjacent first busbars 21 and second busbars 22 are alternately arranged in the second direction D2, with uniform spacing therebetween.

[0038] In some exemplary embodiments, each first busbar 21 and each second busbar 22 are connected to a plurality of pads spaced apart in the second direction D2. The width of the pads in the first direction D1 is greater than the width of the first busbar 21 and the second busbar 22. The interconnect wire 20 can be physically and electrically connected to the pads, and thus conductively connected to the first busbar 21 and the second busbar 22.

[0039] Specifically, if Figure 4As shown, the pads include a first pad 211 conductively connected to the first busbar 21 and a second pad 221 conductively connected to the second busbar 22. The first pad 211 and the second pad 221 are staggered along a first direction D1, so that the interconnection wire 30 connected to the first pad 211 and the interconnection wire 30 connected to 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 the first direction D1, the first main grid 21 and the second main grid 22 are extended along the second direction D2, and the pads of adjacent back contact solar cells with opposite polarities are aligned. Figure 6 Taking the second back-contact solar cell 20b as an example, the first soldering pad 211 of the second back-contact solar cell 20b is aligned with the second soldering pad 221 of the adjacent first back-contact solar cell 20a and the third back-contact solar cell 20c, and the second soldering pad 221 of the second back-contact solar cell 20b is aligned with the first soldering pad 211 of the adjacent first back-contact solar cell 20a and the third back-contact solar cell 20c.

[0041] In some embodiments, as Figure 5 As shown, the back-contact solar cell 20 may include a first busbar 21, a second busbar 22, a first fine grid 23, and a second fine grid 24, but does not include a bonding pad. The interconnection wire 30 may be directly physically and electrically connected to the busbar.

[0042] Interconnect wires 30 connect adjacent back-contact solar cells in series. Interconnect wires 30 extend along a first direction D1 and are spaced apart in a second direction D2. Specifically, the first busbar 21 and second busbar 22 of a back-contact solar cell are each electrically connected to an interconnect wire 30, which in turn electrically connects to the second busbar 22 and first busbar 21 of another back-contact solar cell.

[0043] More specifically, Figure 3 The illustrated back-contact solar cell string includes a first back-contact solar cell 20a, a second back-contact solar cell 20b, and a third back-contact solar cell 20c, arranged sequentially in a first direction D1. Taking the second back-contact solar cell 20b in the middle as an example, interconnecting wires 30 include first interconnecting wires 31 and second interconnecting wires 32, extending along the first direction D1 and alternately spaced apart in the second direction D2. One side of the first interconnecting wire 31 is electrically connected to the first busbar 21 of the second back-contact solar cell 20b, and the other side is electrically connected to the second busbar 22 of the first back-contact solar cell 20a. The second interconnecting wire 32 has one side electrically connected to the second busbar 22 of the second back-contact solar cell 20b and the other side electrically connected to the first busbar 21 of the third back-contact solar cell 20c, thereby connecting the first, second, and third back-contact solar cells 20a, 20b, and 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. If the distance between adjacent interconnecting wires is too large, the interconnecting wires will be arranged too sparsely, thereby increasing the transmission loss of current in the main grid.

[0045] More specifically, in some examples, for back-contact solar cells having solder pads, taking the second back-contact solar cell 20b as an example, the first interconnection wire 31 is physically and electrically connected to the first solder pad 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 solder pad 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 interconnection wire 32 is physically and electrically connected to the second solder pad 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 solder pad 221 of the third back-contact solar cell 20c.

[0046] The interconnection wire 30 is isolated from the main gate and fine gate 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., first interconnecting wire 31) conductively connected to the first busbar 21. This first insulating layer 41 at least electrically isolates the second busbar 22 from the interconnecting wire 30. A second insulating layer 42 is provided along the extension path of the interconnecting wire 30 (e.g., second interconnecting wire 32) conductively connected to the second busbar 22. This second insulating layer 42 at least electrically isolates the first busbar 21 from the interconnecting wire 30. The insulating layer can prevent conductors of different polarities from contacting each other, which could cause a short circuit in the back-contact solar cell. The insulating layer can be an electrically insulating material primarily composed of one or more of 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 the first insulating layer 41 also electrically isolates the first interconnect wire 31 from the second fine gate 24. The second insulating layer 42 extends continuously between the second main gates 22, and the second insulating layer 42 also electrically isolates the second interconnect wire 32 from the first fine gate 23.

[0048] Of course, in some other embodiments, if the fine gates are sparsely arranged, that is, the first fine gate 23 and the second fine gate 24 are arranged at a certain large interval, there is no need to electrically isolate the first interconnection wire 31 from the second fine gate 24 and the second interconnection wire 32 from the first fine gate 23. In other words, the first insulating layer 23 and the second insulating layer 24 can only cover the second main gate 22 and the first main gate 21, respectively, which can save the amount of insulating layer material.

[0049] In some embodiments, the first insulating layer and / or the second insulating layer have a width in the second direction of 1-10 mm. The minimum width of the insulating layer is no less than 1 mm, which reduces the alignment requirements for interconnect wires and helps improve the reliability of the back-contact solar cell module. However, excessively wide insulating layers increase the consumption of insulating layer material.

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

Claims

1. A back contact solar cell module, characterized in that: include: A plurality of back-contact solar cells are arranged along a first direction, each of the back-contact solar cells having a main grid extending along a second direction and a fine grid extending along the first direction, wherein the width of the main grid is greater than the width of the fine grid, and the first direction is perpendicular to the second direction; as well as The interconnecting wires extend along the first direction to 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 with different polarities that are alternately arranged in the first direction, and the interconnection wire includes a first interconnection wire and a second interconnection 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 conductively connected to the interconnection wires, and then are respectively conductively connected to the second main grid and the first main grid of another back-contact solar cell through the interconnection wires.

3. The back contact solar cell module according to claim 2, characterized in that: The invention comprises a first back-contact solar cell, a second back-contact solar cell, and a third back-contact solar cell arranged in sequence along the first direction, wherein one side of the first interconnection 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 interconnection 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 fine grid and a second fine grid, the first fine grids extend parallel to each other along the first direction between adjacent first main grids and second main grids, and are arranged at intervals in the second direction, and the ends of the first fine grids are spaced apart from the second main grids, the second fine grids extend parallel to each other along the first direction between adjacent first main grids and second main grids, and are arranged at intervals in the second direction, and the ends of the second fine grids are spaced apart from the first main grids, and the first fine grids and the second fine grids 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 gates and each of the second main gates are respectively connected to a plurality of pads arranged at intervals 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, and the interconnecting wires are physically and electrically connected to the pads, thereby being conductively 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, the first main grid and the second main grid both extend along the second direction, and the pads of adjacent back-contact solar cells with opposite polarities are aligned.

7. The back contact solar cell module according to claim 2, 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 interconnection wire, and the first insulating layer at least electrically isolates the second main grid from the first interconnection wire. A second insulating layer is provided on the extension path of the second interconnection wire, and the second insulating layer at least electrically isolates the first main grid from the second interconnection 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 further electrically isolates the second fine gate from the first interconnection wire, and the second insulating layer further electrically isolates the first fine gate from the second interconnection wire.

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

11. The back contact solar cell module according to claim 2, characterized in that: The distance between adjacent first interconnection wires and second interconnection wires on each back-contact solar cell does not exceed 20 mm.

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