A back contact cell, cell assembly and photovoltaic system

Abstract

This invention relates to the field of solar cell technology, specifically disclosing a back-contact solar cell, a solar module, and a photovoltaic system. The back-contact solar cell includes: a substrate, the back side of which includes alternating first and second regions; a first doped layer, at least partially disposed in the first region, wherein in the first region, the first doped layer includes a first collecting portion extending along a first direction and a first collecting portion extending along a second direction, the first and second directions being intersected; a second doped layer, at least partially disposed in the second region, wherein the first and second doped layers have opposite polarities, and in the second region, the second doped layer includes a second collecting portion extending along the first direction and a second collecting portion extending along the second direction; a first electrical connection portion, electrically connected to its adjacent first collecting portion, first collecting portion, and second collecting portion; and / or, a second electrical connection portion, electrically connected to its adjacent second collecting portion, first collecting portion, and second collecting portion. This invention can effectively improve the heat spot resistance and stability of the solar cell, thereby improving the overall long-term reliability and safety of the solar module, while ensuring photoelectric conversion efficiency, and is easy to industrialize.

Description

Technical Field

[0001] This invention relates to the field of solar cell technology, and more particularly to a back-contact solar cell, a solar cell module, and a photovoltaic system. Background Technology

[0002] During actual operation, back-contact batteries are prone to localized heating due to the hot spot effect. This heating not only reduces the battery's photoelectric conversion efficiency but also easily causes localized overheating, which in turn damages the battery structure.

[0003] In existing technologies, the main improvement approach to mitigate the negative impact of hot spot effects is to construct anti-hot spot structures in the doped layer. Specifically, the back contact cell includes a first doped region and a second doped region with opposite polarities and arranged in a crisscross pattern. Both the first and second doped regions include a main gate region corresponding to the main gate or solder strip and a sub-gate region corresponding to the sub-gate. Existing anti-hot spot structures typically involve extending a local area of ​​the sub-gate region of either of the two doped regions horizontally or vertically outward, thereby connecting it with the sub-gate region or main gate region of the oppositely doped region to form an anti-hot spot structure.

[0004] In practical use, this type of anti-hot spot structure can only resist the hot spot effect in one direction. On the one hand, it is prone to the risk of failure of the anti-hot spot performance. On the other hand, the anti-hot spot effect is limited and it is difficult to meet the anti-hot spot requirements in actual use, thus affecting the overall reliability and safety of the battery module. Summary of the Invention

[0005] The purpose of this invention is to provide a back-contact solar cell, a solar module, and a photovoltaic system, addressing the limitations of existing technologies.

[0006] This invention can effectively improve the performance and stability of the battery's resistance to hot spots, thereby improving the overall long-term reliability and safety of the battery module, while ensuring photoelectric conversion efficiency, and is easy to industrialize.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: First, the present invention provides a back contact battery cell, comprising: The substrate, the back side of which includes alternating first and second regions; A first doped layer is at least partially disposed in the first region. In the first region, the first doped layer includes a first collection portion extending along a first direction and a first collection portion extending along a second direction, wherein the first direction and the second direction intersect. The second doped layer is at least partially disposed in the second region. The first doped layer and the second doped layer have opposite polarities. In the second region, the second doped layer includes a second collection portion extending along the first direction and a second collection portion extending along the second direction. A first electrical connection portion is electrically connected to its adjacent first collection portion, first receiving portion, and second receiving portion; and / or, The second electrical connection portion is electrically connected to its adjacent second collection portion, first collection portion, and second collection portion.

[0008] In some embodiments, a plurality of the first collecting portions are connected to the same first collecting portion, and the junction between each of the first collecting portions and the first collecting portion forms a first corner, wherein the first electrical connection portion is at least partially disposed at the first corner; and / or Several second collecting parts are connected to the same second collecting part, and the intersection of each second collecting part and the second collecting part forms a second corner, and the second electrical connection part is at least partially provided at the second corner.

[0009] In some embodiments, the first electrical connection portion includes a first edge and a second edge, the first edge being connected to the first collecting portion, and the second edge being connected to the first collecting portion, wherein the ratio between the width of the first edge in the first direction and the width of the second edge in the second direction is 1:1 to 20; and / or, The second electrical connection portion includes a third edge and a fourth edge. The third edge is connected to the second collection portion, and the fourth edge is connected to the second collection portion. The ratio between the width of the third edge in the first direction and the width of the fourth edge in the second direction is 1:1 to 20.

[0010] In some embodiments, the first electrical connection portion includes a first edge and a second edge, the first edge being connected to the first collecting portion, and the second edge being connected to the first collecting portion; the width of the first edge in the first direction is 0.1mm to 1mm, and the width of the second edge in the second direction is 0.1mm to 1mm; and / or, The second electrical connection portion includes a third edge and a fourth edge. The third edge is connected to the second collection portion, and the fourth edge is connected to the second collection portion. The width of the third edge in the first direction is 0.1mm to 1mm, and the width of the fourth edge in the second direction is 0.1mm to 1mm.

[0011] In some embodiments, L 11<W 11 <L 12 , In the formula, W 11 L is the width of the first electrical connection portion at its widest point in the first direction. 11 L is the distance between adjacent first and second collection sections on the side closest to each other in the first direction; 12 In the first direction, the distance between adjacent first and second collection sections on opposite sides; and / or, L 21 <W 21 <L 22 , In the formula, W 21 L is the width of the second electrical connection portion at its widest point in the first direction. 21 L is the distance between adjacent first and second collection sections on the side closest to each other in the first direction; 22 In the first direction, the distance between adjacent first collecting parts and second collecting parts on opposite sides is defined.

[0012] In some embodiments, 1.2*L 11 <W 11 <0.5*L 12 , In the formula, W 11 L is the width of the first electrical connection portion at its widest point in the first direction. 11 L is the distance between adjacent first and second collection sections on the side closest to each other in the first direction; 12 In the first direction, the distance between adjacent first and second collection sections on opposite sides; and / or, 1.2*L 21 <W 21 <0.5*L 22 , In the formula, W 21 L is the width of the second electrical connection portion at its widest point in the first direction. 21 L is the distance between adjacent first and second collection sections on the side closest to each other in the first direction; 22 In the first direction, the distance between adjacent first collecting parts and second collecting parts on opposite sides is defined.

[0013] In some embodiments, D 11 <d 11 <D 12 , In the formula, d 11 D is the width of the first electrical connection at its widest point in the second direction.11 In the second direction, D is the distance between the adjacent sides of the first collecting section and the second collecting section. 12 In the second direction, the length of the second collecting section between adjacent first collecting sections and second collecting sections; and / or, D 21 <d 21 <D 22 , In the formula, d 21 D is the width of the second electrical connection at its widest point in the second direction. 21 D is the distance between adjacent second collecting portions and the first collecting portion on the side closest to each other in the second direction; 22 In the second direction, the length of the first collecting section is between adjacent first collecting sections and second collecting sections.

[0014] In some embodiments, 1.2*D 11 <d 11 <0.1*D 12 , In the formula, d 11 D is the width of the first electrical connection at its widest point in the second direction. 11 In the second direction, D is the distance between the adjacent sides of the first collecting section and the second collecting section. 12 In the second direction, the length of the second collecting section between adjacent first collecting sections and second collecting sections; and / or, 1.2*D 21 <d 21 <0.1*D 22 , In the formula, d 21 D is the width of the second electrical connection at its widest point in the second direction. 21 D is the distance between adjacent second collecting portions and the first collecting portion on the side closest to each other in the second direction; 22 In the second direction, the length of the first collecting section is between adjacent first collecting sections and second collecting sections.

[0015] In some embodiments, an isolation zone is provided between the first region and the second region, wherein... The width of the first electrical connection at its widest point in the first direction is greater than the width of the isolation region in the first direction; and the width of the first electrical connection at its widest point in the second direction is greater than the width of the isolation region in the second direction; and / or, The width of the second electrical connection at its widest point in the first direction is greater than the width of the isolation region in the first direction, and the width of the second electrical connection at its widest point in the second direction is greater than the width of the isolation region in the second direction.

[0016] In some embodiments, the first doped layer further includes a first extension extending beyond the first region, the first electrical connection being the first extension, the first extension being connected to its adjacent first collection portion and first collection portion, and being stacked with its adjacent second collection portion.

[0017] In some embodiments, the second doped layer further includes a second extension extending beyond the second region, the second electrical connection being the second extension, the second extension being connected to its adjacent second collection portion and second collection portion, and being stacked on top of its adjacent first collection portion.

[0018] In some embodiments, the first doped layer further includes a first extension extending beyond the first region, and the second doped layer further includes a second extension extending beyond the second region. The first extension and the second extension together form the first electrical connection. The first extension is connected to its adjacent first collection portion and first collection portion, and is stacked with its adjacent second extension.

[0019] In some embodiments, the first doped layer further includes a first extension extending beyond the first region, and the second doped layer further includes a second extension extending beyond the second region. The first extension and the second extension together form the second electrical connection portion. The second extension is connected to its adjacent second collection portion and second collection portion, and is stacked with its adjacent first extension.

[0020] Furthermore, the present invention provides a photovoltaic system including the aforementioned battery module.

[0021] The beneficial effects of this invention are as follows: In this invention, electrical connections (a first electrical connection and / or a second electrical connection) are introduced into the solar cell, and the same electrical connection simultaneously electrically connects a collection portion and a doped layer of one polarity to a collection portion corresponding to a doped layer of another polarity. Specifically, when the first electrical connection is present, it is electrically connected to its adjacent first collection portion, first collection portion, and second collection portion. When the second electrical connection is present, it is electrically connected to its adjacent second collection portion, first collection portion, and second collection portion. Thus, a multi-directional microcurrent channel is formed between two adjacent collection portions of opposite polarities, and between adjacent collection portions and collection portions of opposite polarities, through the same electrical connection. In scenarios where hot spots such as partial shading occur in the solar cell, the current can be simultaneously diverted and conducted in different directions.

[0022] Compared to existing single-directional anti-hot spot structures, the electrical connection part of the present invention can effectively avoid the problem of anti-hot spot performance failure that is easily caused by existing single-directional anti-hot spot structures. In addition, it can conduct abnormal current more quickly and effectively through multi-directional microcurrent channels in hot spot scenarios, avoiding the continuous rise of local temperature due to insufficient conduction capacity. This can reduce the loss of the battery cell by the hot spot and effectively improve the long-term reliability and safety of the battery module as a whole.

[0023] Compared to the hot spot resistance structure consisting of an independent connection connecting adjacent collectors of opposite polarity and an independent connection connecting adjacent collecting and gathering units of opposite polarity, the electrical connection of this invention simultaneously connects the collecting and gathering units corresponding to one type of doped layer and the collecting unit corresponding to another type of doped layer. In hot spot scenarios, the current in the hot spot region can naturally and adaptively adjust the conduction path and ratio based on the real-time resistance of each path and the voltage difference across the two ends. Channels with larger voltage differences and smaller path resistance will bear more conduction current, thus enabling multi-directional dynamic conduction with shorter paths, resulting in higher conduction efficiency and better hot spot resistance. Furthermore, the structure of this invention is simpler, easier to manufacture, and conducive to industrial production. While ensuring good hot spot resistance, the electrical connection can also be made smaller, reducing the light-shielding area and efficiency loss under normal operating conditions, thus helping to maintain a high conversion efficiency of the battery.

[0024] Therefore, by setting up the electrical connection part, the present invention effectively improves the battery's resistance to hot spots and its stability, thereby improving the overall long-term reliability and safety of the battery module, while ensuring photoelectric conversion efficiency and being easy to industrialize. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the structure of a back contact battery cell (including a first electrical connection portion) according to an embodiment of the present invention.

[0026] Figure 2 for Figure 1 A magnified view of part A.

[0027] Figure 3 for Figure 2 MM-directed cross-section.

[0028] Figure 4 for Figure 2 NN-direction cross-section.

[0029] Figure 5 This is a schematic diagram of the structure of a back contact battery cell (including a second electrical connection portion) according to an embodiment of the present invention.

[0030] Figure 6 for Figure 5 A magnified view of part B.

[0031] Figure 7 for Figure 5 KK-direction cross-section.

[0032] Figure 8 for Figure 5 EE-directed cross-section.

[0033] Figure 9 This is a schematic diagram of the structure of a back contact battery cell (including a first electrical connection portion and a second electrical connection portion) according to an embodiment of the present invention.

[0034] Figure 10 This is a schematic diagram of the structure of a back contact battery cell (including a first electrical connection portion composed of a first extension portion and a second extension portion) according to an embodiment of the present invention.

[0035] Figure 11 This is a schematic diagram of the structure of a back contact battery cell (including a second electrical connection portion composed of a first extension portion and a second extension portion) according to an embodiment of the present invention.

[0036] Figure 12 for Figure 11 A magnified view of part C.

[0037] Figure 13 for Figure 12 Cross-sectional view along the first direction.

[0038] Figure 14 This is a schematic diagram of the structure of a back-contact battery cell (with main grid type) according to an embodiment of the present invention.

[0039] Figure 15 This is a schematic diagram of the structure of a back-contact battery cell (without main grid) according to an embodiment of the present invention.

[0040] In the picture: First doped layer 1, first collection portion 11, first gathering portion 12, first corner 13, first extension portion 14; second doped layer 2, second collection portion 21, second gathering portion 22, second corner 23, second extension portion 24; substrate 3, isolation region 31; first electrical connection portion 4, first edge 41, second edge 42; second electrical connection portion 5, third edge 51, fourth edge 52; first fine gate 61, second fine gate 62; first main gate 71, second main gate 72; first solder strip 81, second solder strip 82. Detailed Implementation

[0041] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the invention, and should not be construed as limiting the invention. Furthermore, it should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0042] In the description of this invention, the terms "first," "second," "third," "fourth," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined with "first," "second," "third," "fourth," etc., may explicitly or implicitly include one or more of the stated features. In the description of this invention, "a plurality of" or "a number" means two or more, unless otherwise explicitly specified.

[0043] In the description of this invention, unless otherwise expressly specified and limited, the term "above" or "below" the second feature may include direct contact between the first and second features, or contact between the first and second features not in direct contact but through another feature between them.

[0044] In the description of this invention, "conductive connection" or "electrical connection" between the first feature and the second feature means that there is no insulation between them. The electrical connection or conductive connection can be achieved by direct contact or indirect contact through other conductive material layers.

[0045] First, see Figures 1 to 3 , Figure 5 and Figure 9 As shown, this invention discloses a back contact battery cell, comprising: The back surface of the substrate 3 includes alternating first and second regions; A first doped layer 1 is at least partially disposed in a first region. In the first region, the first doped layer 1 includes a first gathering portion 11 extending along a first direction and a first collecting portion 12 extending along a second direction, with the first direction and the second direction intersecting. The second doped layer 2 is at least partially disposed in the second region. The first doped layer 1 and the second doped layer 2 have opposite polarities. In the second region, the second doped layer 2 includes a second collection portion 21 extending along a first direction and a second collection portion 22 extending along a second direction. The first electrical connection portion 4 is electrically connected to its adjacent first collection portion 11, first collecting portion 12, and second collecting portion 22; and / or The second electrical connection part 5 is electrically connected to its adjacent second collection part 21, first collection part 12 and second collection part 22.

[0046] Understandably, in the same solar cell, either the first electrical connection part 4 or the second electrical connection part 5 can be provided, or both the first electrical connection part 4 and the second electrical connection part 5 can be provided simultaneously. Specifically: In the first specific implementation, see Figures 1 to 4 As shown, in the same battery cell, only the first electrical connection portion 4 may be provided. Specifically, this invention discloses a back contact battery cell, comprising: The back surface of the substrate 3 includes alternating first and second regions; A first doped layer 1 is at least partially disposed in a first region. In the first region, the first doped layer 1 includes a first gathering portion 11 extending along a first direction and a first collecting portion 12 extending along a second direction, with the first direction and the second direction intersecting. The second doped layer 2 is at least partially disposed in the second region. The first doped layer 1 and the second doped layer 2 have opposite polarities. In the second region, the second doped layer 2 includes a second collection portion 21 extending along a first direction and a second collection portion 22 extending along a second direction. The first electrical connection part 4 is electrically connected to its adjacent first collection part 11, first collection part 12 and second collection part 22.

[0047] In the second specific implementation, see Figures 5 to 8 As shown, in the same battery cell, only the second electrical connection portion 5 may be provided. Specifically, the present invention discloses a back contact battery cell, comprising: The back surface of the substrate 3 includes alternating first and second regions; A first doped layer 1 is at least partially disposed in a first region. In the first region, the first doped layer 1 includes a first gathering portion 11 extending along a first direction and a first collecting portion 12 extending along a second direction, with the first direction and the second direction intersecting. The second doped layer 2 is at least partially disposed in the second region. The first doped layer 1 and the second doped layer 2 have opposite polarities. In the second region, the second doped layer 2 includes a second collection portion 21 extending along a first direction and a second collection portion 22 extending along a second direction. The second electrical connection part 5 is electrically connected to its adjacent second collection part 21, first collection part 12 and second collection part 22.

[0048] In the third specific implementation, see Figure 9 As shown, a first electrical connection portion 4 and a second electrical connection portion 5 may be provided in the same battery cell. Specifically, the present invention discloses a back contact battery cell, comprising: The back surface of the substrate 3 includes alternating first and second regions; A first doped layer 1 is at least partially disposed in a first region. In the first region, the first doped layer 1 includes a first gathering portion 11 extending along a first direction and a first collecting portion 12 extending along a second direction, with the first direction and the second direction intersecting. The second doped layer 2 is at least partially disposed in the second region. The first doped layer 1 and the second doped layer 2 have opposite polarities. In the second region, the second doped layer 2 includes a second collection portion 21 extending along a first direction and a second collection portion 22 extending along a second direction. The first electrical connection portion 4 is electrically connected to its adjacent first collection portion 11, first collecting portion 12, and second collecting portion 22; and, The second electrical connection part 5 is electrically connected to its adjacent second collection part 21, first collection part 12 and second collection part 22.

[0049] In this invention, electrical connections (first electrical connection 4 and / or second electrical connection 5) are introduced into the solar cell, and the same electrical connection simultaneously electrically connects the collection and gathering portions corresponding to a doped layer of one polarity and the collection portion corresponding to a doped layer of another polarity. Specifically, when the first electrical connection 4 is present, it is electrically connected to its adjacent first collection portion 11, first collection portion 12, and second collection portion 22. When the second electrical connection 5 is present, it is electrically connected to its adjacent second collection portion 21, first collection portion 12, and second collection portion 22. Thus, a multi-directional microcurrent channel is formed between two adjacent collection portions of opposite polarities and between adjacent collection portions of opposite polarities through the same electrical connection. In scenarios where hot spots such as partial shading occur in the solar cell, the current can be simultaneously diverted and conducted in different directions.

[0050] Compared to existing single-directional anti-hot spot structures, the electrical connection part of the present invention can effectively avoid the problem of anti-hot spot performance failure that is easily caused by existing single-directional anti-hot spot structures. In addition, it can conduct abnormal current more quickly and effectively through multi-directional microcurrent channels in hot spot scenarios, avoiding the continuous rise of local temperature due to insufficient conduction capacity. This can reduce the loss of the battery cell by the hot spot and effectively improve the long-term reliability and safety of the battery module as a whole.

[0051] Compared to the anti-hot spot structure consisting of an independent connection connecting adjacent collection sections of opposite polarity and an independent connection connecting adjacent gathering sections and collection sections of opposite polarity, the electrical connection of this invention simultaneously connects the gathering section and collection section corresponding to one polarity of doped layer and the collection section corresponding to another polarity of doped layer. In hot spot scenarios, the current in the hot spot region can naturally and adaptively adjust the conduction path and ratio based on the real-time resistance of each path and the voltage difference across both ends. The channel with the larger the voltage difference and the smaller the path resistance will bear more conduction current, thus enabling the current to achieve multi-directional dynamic conduction with a shorter path, resulting in higher conduction efficiency and better anti-hot spot effect. Simultaneously, the structure of this invention is simpler, easier to manufacture, and conducive to industrial production. While ensuring good anti-hot spot effect, the electrical connection can also be made smaller, reducing the light-shielding area and lowering efficiency loss under normal operating conditions (i.e., when the battery is not obstructed by foreign objects or in non-hot spot scenarios), thus helping to maintain a high conversion efficiency of the battery.

[0052] Therefore, by setting up the electrical connection part, the present invention effectively improves the battery's resistance to hot spots and its stability, thereby improving the overall long-term reliability and safety of the battery module, while ensuring photoelectric conversion efficiency and being easy to industrialize.

[0053] Understandably, the substrate 3 has a first surface and a second surface disposed opposite to each other, one of which is the light-receiving surface (usually referred to as the front side of the substrate 3), and the other is the back-lighting surface (usually referred to as the back side of the substrate 3). In this specification, the first surface is referred to as the back-lighting surface, and the second surface as the light-receiving surface. The light-receiving surface generally refers to the side that receives light. Its surface may also be provided with passivation layers, anti-reflection layers, etc. (not shown in the figures), which are common in the art, but are not limited thereto. It should be noted that in some embodiments, the back-lighting surface may also absorb the light incident through the back-lighting surface, thereby generating a photocurrent. Its surface may also be provided with tunneling oxide layers, passivation layers, anti-reflection layers, etc. (not shown in the figures), which are common in the art.

[0054] In practical applications, the embodiments of the present invention do not specifically limit the material and conductivity type of the substrate 3. For example, the substrate 3 can be a silicon substrate, such as monocrystalline silicon, microcrystalline silicon, polycrystalline silicon, or amorphous silicon, or a germanium-silicon substrate, germanium substrate, or gallium arsenide substrate, but is not limited thereto. Its conductivity type can be N-type or P-type. Preferably, the substrate 3 is a silicon substrate.

[0055] Understandably, in terms of conductivity type, the polarity of the first doped layer 1 and the second doped layer 2 can be the same as or opposite to the polarity of the substrate 3, as long as the polarity of the first doped layer 1 is opposite to that of the second doped layer 2. Either the first doped layer 1 and / or the second doped layer 2 is made of monocrystalline silicon, microcrystalline silicon, polycrystalline silicon, or amorphous silicon doped with a P-type dopant element (e.g., group III elements such as B, Ga, or In), and the other is made of monocrystalline silicon, microcrystalline silicon, polycrystalline silicon, or amorphous silicon doped with an N-type dopant element (e.g., group V elements such as P, As, or Sb). Preferably, the first doped layer 1 and / or the second doped layer 2 are polycrystalline silicon.

[0056] In some embodiments, see Figures 1 to 2 As shown, a plurality of first collecting sections 12 are connected to the same first collecting section 11, and the junctions between each first collecting section 12 and the first collecting section 11 form a first corner 13. A first electrical connection section 4 is at least partially located at the first corner 13; and / or, See Figures 5 to 6 As shown, several second collecting parts 22 are connected to the same second collecting part 21, and the intersection of each second collecting part 22 and the second collecting part 21 forms a second corner 23. The second electrical connection part 5 is at least partially provided at the second corner 23.

[0057] By setting the electrical connection at the corner of the collecting and converging parts of the same polarity (that is, setting the first electrical connection 4 at the first corner 13 formed by the intersection of the first collecting part 12 and the first converging part 11, and setting, and / or setting the second electrical connection 5 at the second corner 23 formed by the intersection of the second collecting part 22 and the second converging part 21), it is possible to simultaneously electrically connect the converging and collecting parts corresponding to one polarity of doped layer and the collecting part corresponding to another polarity of doped layer with a smaller electrical connection, further shortening the current conduction path, reducing conductivity impedance and conduction loss, improving the anti-hot spot performance while reducing the light-shielding area of ​​the electrical connection, reducing efficiency loss under normal operating conditions, so as to improve the long-term reliability of the battery module while ensuring photoelectric conversion efficiency. At the same time, the electrical connection is easier to position, which is beneficial for industrial production.

[0058] In some embodiments, see Figures 1 to 2 As shown, the first electrical connection portion 4 includes a first edge 41 and a second edge 42. The first edge 41 is connected to the first collecting portion 11, and the second edge 42 is connected to the first collecting portion 12. The ratio (S1 / S2) between the width S1 of the first edge 41 in the first direction and the width S2 of the second edge 42 in the second direction is 1:1 to 20; and / or, See Figures 5 to 6 As shown, the second electrical connection portion 5 includes a third edge 51 and a fourth edge 52. The third edge 51 is connected to the second collection portion 21, and the fourth edge 52 is connected to the second collection portion 22. The ratio (S3 / S4) between the width S3 of the third edge 51 in the first direction and the width S4 of the fourth edge 52 in the second direction is 1:1 to 20.

[0059] For example, the ratio S1 / S2 between S1 and S2 can be 1:1, 1:2, 1:3, 1:4, 1:5, 1:6, 1:7, 1:8, 1:9, 1:10, 1:11, 1:12, 1:13, 1:14, 1:15, 1:16, 1:17, 1:18, 1:19 or 1:20, but is not limited to these.

[0060] For example, the ratio S3 / S4 between S3 and S4 can be 1:1, 1:2, 1:3, 1:4, 1:5, 1:6, 1:7, 1:8, 1:9, 1:10, 1:11, 1:12, 1:13, 1:14, 1:15, 1:16, 1:17, 1:18, 1:19 or 1:20, but is not limited to these.

[0061] When S1 and S2 are the same, the graphic design and manufacturing process can be simplified. When S2 > S1, by adjusting the width of the part connecting the first electrical connection part 4 with the first collection part 11 and the first collecting part 12, that is, the width S1 of the first edge 41 in the first direction and the width S2 of the second edge 42 in the second direction, the conductive contact area of ​​the first electrical connection part 4 with the first collection part 11 and the first collecting part 12 can be adapted to their conductive characteristics and current transmission requirements. In this way, while ensuring the photoelectric conversion efficiency, the current conduction efficiency and overall anti-hot spot effect in hot spot scenarios can be further improved, and the overall performance of the battery module is better.

[0062] When S3 and S4 are the same, the graphic design and manufacturing process can be simplified. When S4 > S3, by adjusting the width of the part connecting the second electrical connection part 5 with the second collection part 21 and the second collection part 22, that is, the width S3 of the third edge 51 in the first direction and the width S4 of the fourth edge 52 in the second direction, the conductive contact area of ​​the second electrical connection part 5 with the second collection part 21 and the second collection part 22 can be adapted to their conductive characteristics and current transmission requirements. In this way, while ensuring the photoelectric conversion efficiency, the current conduction efficiency and overall anti-hot spot effect in hot spot scenarios can be further improved, and the overall performance of the battery module is better.

[0063] In some embodiments, see Figures 1 to 2 As shown, the first electrical connection portion 4 includes a first edge 41 and a second edge 42. The first edge 41 is connected to the first collecting portion 11, and the second edge 42 is connected to the first collecting portion 12. The width S1 of the first edge 41 in a first direction is 0.1mm to 1mm, and the width S2 of the second edge 42 in a second direction is 0.1mm to 1mm; and / or, See Figures 5 to 6 As shown, the second electrical connection portion 5 includes a third edge 51 and a fourth edge 52. The third edge 51 is connected to the second collection portion 21, and the fourth edge 52 is connected to the second collection portion 22. The width S3 of the third edge 51 in the first direction is 0.1mm to 1mm, and the width S4 of the fourth edge 52 in the second direction is 0.1mm to 1mm.

[0064] For example, S1, S2, S3, and S4 can each be independently 0.1mm, 0.15mm, 0.2mm, 0.25mm, 0.3mm, 0.35mm, 0.4mm, 0.45mm, 0.5mm, 0.55mm, 0.6mm, 0.65mm, 0.7mm, 0.8mm, 0.85mm, 0.9mm, 0.95mm, or 1mm, but are not limited to these. Within this range, it can adapt to most products of various sizes on the market, ensuring that while maintaining photoelectric conversion efficiency, it can further improve the current conduction efficiency and overall hot spot resistance in hot spot scenarios.

[0065] In some embodiments, see Figures 1 to 2 As shown, L 11 <W 11 <L 12 , In the formula, W 11 L is the width of the first electrical connection portion 4 at its widest point in the first direction. 11 L is the distance between adjacent first collecting sections 12 and second collecting sections 22 on one side of each other in the first direction; 12 In the first direction, the distance between adjacent first collecting sections 12 and second collecting sections 22 on opposite sides; and / or, See Figures 5 to 6 As shown, L 21 <W 21 <L 22 , In the formula, W 21 L is the width of the second electrical connection portion 5 at its widest point in the first direction. 21 L is the distance between adjacent first collecting sections 12 and second collecting sections 22 on one side of each other in the first direction; 22 The distance between adjacent first collecting section 12 and second collecting section 22 on one side away from each other in the first direction.

[0066] Through L 11 <W 11 The configuration ensures that the same first electrical connection part 4 can be electrically connected to its adjacent first collection part 12 and second collection part 22 simultaneously, through W 11 <L 12 The design avoids an excessively large area of ​​composite contact, thereby ensuring the battery has anti-hot spot performance while reducing the adverse effects of excessive composite contact area on battery conversion efficiency under normal operating conditions. This balances the long-term reliability and photoelectric performance of the battery module and optimizes the overall performance of the battery module.

[0067] L 21 <W 21 <L 22The principle is the same, so I will not repeat it here.

[0068] In some embodiments, see Figures 1 to 2 As shown, 1.2*L 11 <W 11 <0.5*L 12 , In the formula, W 11 L is the width of the first electrical connection portion 4 at its widest point in the first direction. 11 L is the distance between adjacent first collecting sections 12 and second collecting sections 22 on one side of each other in the first direction; 12 In the first direction, the distance between adjacent first collecting sections 12 and second collecting sections 22 on opposite sides; and / or, See Figures 5 to 6 As shown, 1.2*L 21 <W 21 <0.5*L 22 , In the formula, W 21 L is the width of the second electrical connection portion 5 at its widest point in the first direction. 21 L is the distance between adjacent first collecting sections 12 and second collecting sections 22 on one side of each other in the first direction; 22 The distance between adjacent first collecting section 12 and second collecting section 22 on one side away from each other in the first direction.

[0069] Through 1.2*L 11 <W 11 <0.5*L 12 This configuration, on the one hand, ensures that the width W of the first electrical connection portion 4 at its widest point in the first direction is... 11 Sufficiently wide, it can form a stable conductive connection with its adjacent first collecting part 12 and second collecting part 22, and reserves process tolerance space to allow for a certain degree of size and position deviation during the preparation process, reducing production precision requirements and improving production yield; on the other hand, it can effectively avoid the composite contact area being too large, reduce composite loss, and ensure photoelectric conversion efficiency under normal operating conditions; at the same time, when the outline of the first electrical connection part 4 is rectangular, the width W at the widest point of the first electrical connection part 4 in the first direction is... 11 W has the same width S1 as the first edge 41 in the first direction. 11 Controlled at 1.2*L 11 <W 11 <0.5*L 12 Within this range, the conductive contact area between the first electrical connection part 4 and the first collection part 11 can be better adapted to its current transmission requirements, thereby improving the current conduction efficiency and overall anti-hot spot effect in hot spot scenarios while ensuring photoelectric conversion efficiency.

[0070] 1.2*L 21 <W 21 <0.5*L 22 The principle is the same, so I will not repeat it here.

[0071] In some embodiments, see Figures 1 to 2 As shown, D 11 <d 11 <D 12 , In the formula, d 11 D is the width of the first electrical connection 4 at its widest point in the second direction. 11 D is the distance between adjacent first collecting section 11 and second collecting section 22 on one side closer to each other in the second direction; 12 In the second direction, the length of the second collecting section 22 between adjacent first collecting section 11 and second collecting section 21; and / or, See Figures 5 to 6 As shown, D 21 <d 21 <D 22 , In the formula, d 21 D is the width of the second electrical connection 5 at its widest point in the second direction. 21 In the second direction, D is the distance between adjacent second collecting sections 21 and first collecting sections 12 on one side closer to each other; 22 In the second direction, the length of the first collecting section 12 is between adjacent first collecting section 11 and second collecting section 21.

[0072] Through D 11 <d 11 The configuration ensures that the same first electrical connection part 4 can simultaneously be electrically connected to its adjacent first collection part 11 and second collection part 22; through d 11 <D 12 The design avoids an excessively large area of ​​composite contact, thereby ensuring the battery has anti-hot spot performance while reducing the adverse effects of excessive composite contact area on battery conversion efficiency under normal operating conditions. This balances the long-term reliability and photoelectric performance of the battery module and optimizes the overall performance of the battery module.

[0073] D 21 <d 21 <D 22 The principle is the same, so I will not repeat it here.

[0074] In some embodiments, see Figures 1 to 2 As shown, 1.2*D 11 <d 11 <0.1*D 12 , In the formula, d 11 D is the width of the first electrical connection 4 at its widest point in the second direction. 11 D is the distance between adjacent first collecting section 11 and second collecting section 22 on one side closer to each other in the second direction; 12 In the second direction, the length of the second collecting section 22 between adjacent first collecting section 11 and second collecting section 21; and / or, See Figures 5 to 6 As shown, 1.2*D 21 <d 21 <0.1*D 22 , In the formula, d 21 D is the width of the second electrical connection 5 at its widest point in the second direction. 21 In the second direction, D is the distance between adjacent second collecting sections 21 and first collecting sections 12 on one side closer to each other; 22 In the second direction, the length of the first collecting section 12 is between adjacent first collecting section 11 and second collecting section 21.

[0075] Through 1.2*D 11 <d 11 <0.1*D 12 The configuration ensures, on the one hand, the width d at the widest point of the first electrical connection 4 in the second direction. 11 Sufficiently wide, it can form a stable conductive connection with its adjacent second collecting part 22 and first collecting part 11, and reserves process tolerance space to allow for a certain degree of size and position deviation during the preparation process, reducing production precision requirements and improving production yield; on the other hand, it can effectively avoid the composite contact area being too large, reduce composite loss, and ensure photoelectric conversion efficiency under normal operating conditions; at the same time, when the outline of the first electrical connection part 4 is rectangular, the width d at the widest point of the first electrical connection part 4 in the second direction is... 11 With the same width S2 as the second edge 42 in the second direction, within the above range, the conductive contact area between the first electrical connection part 4 and the first collection part 12 can be better adapted to its current transmission requirements, thereby improving the current conduction efficiency and overall anti-hot spot effect in hot spot scenarios while ensuring photoelectric conversion efficiency.

[0076] 1.2*D 21 <d 21 <0.1*D 22 The principle is the same, so I will not repeat it here.

[0077] In some embodiments, see Figures 1 to 3 As shown, an isolation zone 31 is provided between the first area and the second area, wherein, The width W of the first electrical connection part 4 at its widest point in the first direction 11 Width W of the isolation zone 31 in the first direction g The width d of the first electrical connection 4 at its widest point in the second direction 11 Width d of the isolation zone 31 in the second direction g That is, W 11 >W g d 11 >d g ; and / or, See Figures 5 to 7 As shown, the width W at the widest point of the second electrical connection portion 5 in the first direction is... 21 Width W of the isolation zone 31 in the first direction g The width d of the second electrical connection 5 at its widest point in the second direction 21 Width d of the isolation zone 31 in the second direction g That is, W 21 >W g d 21 >d g .

[0078] Through W 11 >W g d 11 >d g The configuration ensures that the first electrical connection part 4 can span the first region and the second region, and is simultaneously electrically connected to the first collection part 11 and the first collection part 12 located in the first region, and the second collection part 22 located in the second region.

[0079] Through W 21 >W g d 21 >d g The configuration ensures that the second electrical connection part 5 can span the first region and the second region, and simultaneously conduct electricity to the second collection part 21 and the second collection part 22 located in the second region, and the first collection part 12 located in the first region.

[0080] In some embodiments, the isolation zone 31 may be configured as an isolation trough, but is not limited thereto.

[0081] In some embodiments, see Figures 1 to 4 As shown, the first doped layer 1 further includes a first extension portion 14 extending outside the first region. The first electrical connection portion 4 is the first extension portion 14. The first extension portion 14 is connected to its adjacent first collection portion 11 and first collection portion 12, and is stacked with its adjacent second collection portion 22. At this time, the first extension portion 14 (first electrical connection portion 4) of the first doped layer 1 and the second collection portion 22 of the second doped layer 2 are stacked with each other in the second region and are in composite contact at the stacking point.

[0082] Understandably, at this time, the polarity of the first electrical connection 4 is the same as the polarity of the first doped layer 1. At the stacking point, the first extension 14 can be disposed on the side of the second collection part 22 facing away from the substrate 3, or it can be disposed on the side of the second collection part 22 facing the substrate 3. Preferably, the first extension 14 is disposed on the side of the second collection part 22 facing away from the substrate 3, which simplifies the preparation process and facilitates manufacturing.

[0083] In some embodiments, see Figures 5 to 8 As shown, the second doped layer 2 also includes a second extension 24 extending beyond the second region. The second electrical connection 5 is the second extension 24. The second extension 24 is connected to its adjacent second collection portion 21 and second collection portion 22, and is stacked with its adjacent first collection portion 12. At this time, the second extension 24 (second electrical connection 5) of the second doped layer 2 and the first collection portion 12 of the first doped layer 1 are stacked with each other in the first region and are in composite contact at the stacking point.

[0084] Understandably, at this time, the polarity of the second electrical connection portion 5 is the same as the polarity of the second doped layer 2. At the stacking point, the second extension portion 24 can be disposed on the side of the first collection portion 12 facing away from the substrate 3, or it can be disposed on the side of the first collection portion 12 facing the substrate 3. Preferably, the second extension portion 24 is disposed on the side of the first collection portion 12 facing away from the substrate 3, which simplifies the preparation process and facilitates manufacturing.

[0085] In some embodiments, see Figure 10 As shown, the first doped layer 1 further includes a first extension 14 extending outside the first region, and the second doped layer 2 further includes a second extension 24 extending outside the second region. The first extension 14 and the second extension 24 together form a first electrical connection 4. The first extension 14 is connected to its adjacent first collection portion 11 and first collection portion 12, and is stacked with its adjacent second extension 24. At this time, the stacking point of the first extension 14 and the second extension 24 is located in the region between the first region and the second region, and they are in composite contact at the stacking point.

[0086] Understandably, at the layering point, the second extension 24 can be disposed on the side of the first extension 14 facing away from the base 3, or it can be disposed on the side of the first extension 14 facing the base 3.

[0087] Compared to the scheme in which the first extension 14 and the second extension 24 together form the first electrical connection 4, it is preferable to use the first extension 14 as the first electrical connection 4, as the manufacturing process is simpler and easier to produce.

[0088] In some embodiments, see Figures 11 to 13As shown, the first doped layer 1 further includes a first extension 14 extending outside the first region, and the second doped layer 2 further includes a second extension 24 extending outside the second region. The first extension 14 and the second extension 24 together form a second electrical connection 5. The second extension 24 is connected to its adjacent second collection portion 21 and second collection portion 22, and is stacked with its adjacent first extension 14. At this time, the stacking point of the first extension 14 and the second extension 24 is located in the region between the first region and the second region, and they are in composite contact at the stacking point.

[0089] Understandably, at the layering point, the second extension 24 can be disposed on the side of the first extension 14 facing away from the base 3, or it can be disposed on the side of the first extension 14 facing the base 3.

[0090] Compared to the scheme in which the first extension 14 and the second extension 24 together form the second electrical connection 5, it is preferable to use the second extension 24 as the second electrical connection 5, as the manufacturing process is simpler and easier to produce.

[0091] It is understood that the above embodiments show the use of a first doped layer and / or a second doped layer as the first electrical connection part 4 or the second electrical connection part 5. In some other embodiments, other conductive materials may also be used as the first electrical connection part 4 or the second electrical connection part 5.

[0092] In some embodiments, see Figure 14 As shown, the back contact battery cell of the present invention can be a back contact battery with a main grid. Specifically, the battery cell further includes: The first main grid 71 is located on the side of the first collection section 11 facing away from the base 3; The first fine grid 61 is at least partially disposed on the side of the first collecting part 12 facing away from the base 3; The second main grid 72 is located on the side of the second collection section 21 facing away from the base 3; The second fine grid 62 is at least partially disposed on the side of the second collection section 22 facing away from the base 3.

[0093] Understandably, the first fine gate 61 and the second fine gate 62 have opposite conductivity types, the first main gate 71 and the first fine gate 61 have the same conductivity type (i.e., both are positive or both are negative), the second main gate 72 and the second fine gate 62 have the same conductivity type, the same first main gate 71 is conductively connected to several first fine gates 61, and the same second main gate 72 is conductively connected to several second fine gates 62.

[0094] In some embodiments, see Figure 15 As shown, the back contact battery cell of the present invention can be a gridless back contact battery. Specifically, the battery cell further includes: The first welding strip 81 is located on the side of the first collection part 11 facing away from the substrate 3; The first fine grid 61 is at least partially disposed on the side of the first collecting part 12 facing away from the base 3; The second welding strip 82 is located on the side of the second collection section 21 facing away from the substrate 3; The second fine grid 62 is at least partially disposed on the side of the second collection section 22 facing away from the base 3.

[0095] Understandably, the first fine gate 61 and the second fine gate 62 have opposite conductivity types, the first solder strip 81 and the first fine gate 61 have the same conductivity type (i.e., both are positive or both are negative), the second solder strip 82 and the second fine gate 62 have the same conductivity type, the same first solder strip 81 is conductively connected to several first fine gates 61, and the same second solder strip 82 is conductively connected to several second fine gates 62.

[0096] Secondly, the present invention discloses a battery assembly, including the aforementioned back contact battery cell.

[0097] A battery assembly may include multiple battery cells, which can be connected in series to form a battery string. The battery strings can be connected in series, in parallel, or in a series-parallel combination to achieve current output. For example, the connection between the battery cells can be achieved by welding solder strips, or the connection between the battery strings can be achieved by busbars.

[0098] The battery assembly may also include a metal frame, a backsheet, photovoltaic glass, and an encapsulant film (not shown in the figures).

[0099] Furthermore, this invention discloses a photovoltaic system including the aforementioned battery module.

[0100] In this embodiment, the photovoltaic system can be applied in photovoltaic power plants, such as ground-mounted power plants, rooftop power plants, and floating power plants. It can also be applied to equipment or devices that utilize solar energy to generate electricity, such as user solar power supplies, solar streetlights, solar cars, and solar buildings. Of course, it is understood that the application scenarios of the photovoltaic system are not limited to these; that is, the photovoltaic system can be applied in all fields that require solar energy to generate electricity. Taking a photovoltaic power generation system network as an example, the photovoltaic system may include a photovoltaic array, a combiner box, and an inverter. The photovoltaic array may be an array combination of multiple battery modules; for example, multiple battery modules can form multiple photovoltaic arrays. The photovoltaic array is connected to the combiner box, which can collect the current generated by the photovoltaic array. The collected current flows through the inverter and is converted into AC power required by the mains power grid before being connected to the mains power grid to achieve solar power supply.

[0101] In the description of this specification, references to terms such as "some embodiments," "exemplary," "example," or "for example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with an embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0102] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-described technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A back contact battery cell, characterized in that, include: The substrate, the back side of which includes alternating first and second regions; A first doped layer is at least partially disposed in the first region. In the first region, the first doped layer includes a first collection portion extending along a first direction and a first collection portion extending along a second direction, wherein the first direction and the second direction intersect. The second doped layer is at least partially disposed in the second region. The first doped layer and the second doped layer have opposite polarities. In the second region, the second doped layer includes a second collection portion extending along the first direction and a second collection portion extending along the second direction. The first electrical connection portion is electrically connected to the adjacent first collection portion, first gathering portion and second gathering portion. And / or, The second electrical connection portion is electrically connected to its adjacent second collection portion, first collection portion, and second collection portion.

2. The back contact battery cell according to claim 1, characterized in that, A plurality of first collecting sections are connected to the same first collecting section, and the junctions between each first collecting section and the first collecting section form a first corner, wherein the first electrical connection is at least partially disposed at the first corner; and / or, Several second collecting parts are connected to the same second collecting part, and the intersection of each second collecting part and the second collecting part forms a second corner, and the second electrical connection part is at least partially provided at the second corner.

3. A back contact battery cell according to claim 1, characterized in that, The first electrical connection portion includes a first edge and a second edge. The first edge is connected to the first collecting portion, and the second edge is connected to the first collecting portion. The ratio between the width of the first edge in the first direction and the width of the second edge in the second direction is 1:1 to 20; and / or, The second electrical connection portion includes a third edge and a fourth edge. The third edge is connected to the second collection portion, and the fourth edge is connected to the second collection portion. The ratio between the width of the third edge in the first direction and the width of the fourth edge in the second direction is 1:1 to 20.

4. A back contact battery cell according to claim 1, characterized in that, The first electrical connection portion includes a first edge and a second edge. The first edge is connected to the first collecting portion, and the second edge is connected to the first collecting portion. The width of the first edge in the first direction is 0.1 mm to 1 mm, and the width of the second edge in the second direction is 0.1 mm to 1 mm; and / or, The second electrical connection portion includes a third edge and a fourth edge. The third edge is connected to the second collection portion, and the fourth edge is connected to the second collection portion. The width of the third edge in the first direction is 0.1mm to 1mm, and the width of the fourth edge in the second direction is 0.1mm to 1mm.

5. A back contact battery cell according to claim 1, characterized in that, L 11 <W 11 <L 12 , In the formula, W 11 L is the width of the first electrical connection portion at its widest point in the first direction. 11 L is the distance between adjacent first and second collection sections on the side closest to each other in the first direction; 12 In the first direction, the distance between adjacent first and second collection sections on opposite sides; and / or, L 21 <W 21 <L 22 , In the formula, W 21 L is the width of the second electrical connection portion at its widest point in the first direction. 21 L is the distance between adjacent first and second collection sections on the side closest to each other in the first direction; 22 In the first direction, the distance between adjacent first collecting parts and second collecting parts on opposite sides is defined.

6. A back contact battery cell according to claim 1, characterized in that, 1.2*L 11 <W 11 <0.5*L 12 , In the formula, W 11 L is the width of the first electrical connection portion at its widest point in the first direction. 11 L is the distance between adjacent first and second collection sections on the side closest to each other in the first direction; 12 In the first direction, the distance between adjacent first and second collection sections on opposite sides; and / or, 1.2*L 21 <W 21 <0.5*L 22 , In the formula, W 21 L is the width of the second electrical connection portion at its widest point in the first direction. 21 L is the distance between adjacent first and second collection sections on the side closest to each other in the first direction; 22 In the first direction, the distance between adjacent first collecting parts and second collecting parts on opposite sides is defined.

7. A back contact battery cell according to claim 1, characterized in that, D 11 <d 11 <D 12 , In the formula, d 11 D is the width of the first electrical connection at its widest point in the second direction. 11 In the second direction, D is the distance between the adjacent sides of the first collecting section and the second collecting section. 12 In the second direction, the length of the second collecting section between adjacent first collecting sections and second collecting sections; and / or, D 21 <d 21 <D 22 , In the formula, d 21 D is the width of the second electrical connection at its widest point in the second direction. 21 D is the distance between adjacent second collecting portions and the first collecting portion on the side closest to each other in the second direction; 22 In the second direction, the length of the first collecting section is between adjacent first collecting sections and second collecting sections.

8. A back contact battery cell according to claim 1, characterized in that, 1.2*D 11 <d 11 <0.1*D 12 , In the formula, d 11 D is the width of the first electrical connection at its widest point in the second direction. 11 In the second direction, D is the distance between the adjacent sides of the first collecting section and the second collecting section. 12 In the second direction, the length of the second collecting section between adjacent first collecting sections and second collecting sections; and / or, 1.2*D 21 <d 21 <0.1*D 22 , In the formula, d 21 D is the width of the second electrical connection at its widest point in the second direction. 21 D is the distance between adjacent second collecting portions and the first collecting portion on the side closest to each other in the second direction; 22 In the second direction, the length of the first collecting section is between adjacent first collecting sections and second collecting sections.

9. A back contact battery cell according to claim 1, characterized in that, An isolation zone is provided between the first area and the second area, wherein, The width of the first electrical connection at its widest point in the first direction is greater than the width of the isolation region in the first direction; and the width of the first electrical connection at its widest point in the second direction is greater than the width of the isolation region in the second direction; and / or, The width of the second electrical connection at its widest point in the first direction is greater than the width of the isolation region in the first direction, and the width of the second electrical connection at its widest point in the second direction is greater than the width of the isolation region in the second direction.

10. A back contact battery cell according to claim 1, characterized in that, The first doped layer further includes a first extension extending beyond the first region, the first electrical connection being the first extension, the first extension being connected to its adjacent first collection portion and first collection portion, and being stacked with its adjacent second collection portion.

11. A back contact battery cell according to claim 1, characterized in that, The second doped layer further includes a second extension extending beyond the second region, the second electrical connection portion being the second extension portion, the second extension portion being connected to its adjacent second collection portion and second collection portion, and being stacked on top of its adjacent first collection portion.

12. A back contact battery cell according to claim 1, characterized in that, The first doped layer further includes a first extension extending beyond the first region, and the second doped layer further includes a second extension extending beyond the second region. The first extension and the second extension together form the first electrical connection portion. The first extension is connected to its adjacent first collection portion and first collection portion, and is stacked with its adjacent second extension.

13. A back contact battery cell according to claim 1, characterized in that, The first doped layer further includes a first extension extending beyond the first region, and the second doped layer further includes a second extension extending beyond the second region. The first extension and the second extension together form the second electrical connection portion. The second extension is connected to its adjacent second collection portion and second collection portion, and is stacked with its adjacent first extension.

14. A battery assembly, characterized in that, Including a back contact battery cell according to claims 1 to 13.

15. A photovoltaic system, characterized in that, Includes the battery assembly as described in claim 14.

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