Back contact solar cell and cell assembly

Abstract

The present disclosure relates to the technical field of solar cells, and discloses a back contact solar cell and a cell module. The cell comprises a base layer, a passivation contact structure and a grid line structure. The base layer comprises a first edge and a second edge opposite along a first direction, and a third edge and a fourth edge opposite along a second direction. The passivation contact structure comprises a first edge connecting part, a second edge connecting part, a first edge extending part, a second edge extending part and a middle extending part. The grid line structure comprises a first edge connecting grid line, a second edge connecting grid line, a first edge auxiliary grid line and a second edge auxiliary grid line. The outermost grid lines on the short side of the cell are all offset inward relative to the passivation contact structure below, and the grid lines on the passivation contact structure in the middle region are all in the middle of the passivation contact structure below. In this way, the overall space window is large, which helps to improve the printing precision and yield, and ensures that the grid lines in the edge region form effective ohmic contact in the subsequent annealing and sintering process.

Description

Technical Field

[0001] This disclosure relates to the field of solar cell technology, specifically to a back-contact solar cell and its module. Background Technology

[0002] Back-contact solar cells, with both positive and negative electrodes located on the back of the cell, offer significant advantages in reducing front-side shading losses and improving conversion efficiency, making them a key development direction for high-efficiency crystalline silicon solar cells. In the structural design of back-contact solar cells, the passivation contact structure (such as a polycrystalline silicon layer or an amorphous silicon layer) and the layout of the electrode grid lines on it have a crucial impact on carrier collection efficiency and cell reliability.

[0003] In related technologies, back-contact solar cells typically employ the same layout for the passivated contact structure at the edges and the electrode grid lines thereon as in the central region. However, in actual production, it has been found that the electrode grid lines in the edge region, being close to the cell edge, are susceptible to factors such as printing accuracy, plating around the edges, and incomplete annealing and sintering. This can lead to poor electrode contact, printing misalignment, or even exceeding the cell boundary, resulting in insufficient carrier collection capacity and a higher risk of edge leakage in the edge region. Consequently, this affects cell yield and performance consistency.

[0004] To address these issues, some solutions attempt to adjust the distance between the edge passivation contact structure and the central passivation contact structure, or the distance between the edge gate lines and the central gate lines, to balance edge carrier collection and leakage control. However, these solutions do not adequately optimize the layout of the edge structure and fail to effectively solve the problem that the performance of related structures in the overall edge region of the battery is inferior to that in the central region. Therefore, how to improve the contact reliability of the edge structure while ensuring edge carrier collection performance, thereby improving the overall battery performance and photoelectric conversion efficiency, has become an urgent technical problem to be solved in this field. Summary of the Invention

[0005] This disclosure provides a back-contact solar cell and cell assembly to solve the problem that existing cells cannot simultaneously achieve edge carrier collection performance and contact reliability.

[0006] In a first aspect, this disclosure provides a back-contact solar cell, comprising: a substrate layer, a passivation contact structure, and a grid line structure. The substrate layer includes a light-receiving surface and a back-lighting surface opposite each other along the thickness direction, and further includes a first edge and a second edge opposite each other along a first direction and a third edge and a fourth edge opposite each other along a second direction in a plane perpendicular to the thickness direction, wherein the first direction and the second direction are perpendicular. The passivation contact structure is formed on the back-lighting surface of the substrate layer, including a plurality of connecting portions spaced apart along the first direction and a plurality of extension portions spaced apart along the second direction, one end of the extension portions being connected to the connecting portions. The plurality of connecting portions includes at least a first edge connecting portion adjacent to the first edge, a second edge connecting portion adjacent to the second edge, and a plurality of intermediate connecting portions located between the first edge connecting portion and the second edge connecting portion. The plurality of extension portions includes a first edge extension portion adjacent to the third edge, a second edge extension portion adjacent to the fourth edge, and an extension portion located between the first edge extension portion and the second edge extension portion. The grid structure includes at least a first edge connecting grid line, a second edge connecting grid line, and multiple sub-grid lines. The first edge connecting grid line is disposed on the first edge connecting portion, the second edge connecting grid line is disposed on the second edge connecting portion, and the multiple sub-grid lines include a first edge sub-grid line disposed on the first edge extension portion, a second edge sub-grid line disposed on the second edge extension portion, and multiple intermediate sub-grid lines disposed on the intermediate extension portion. In a first direction, the first edge connecting grid line is offset relative to the center line of the first edge connecting portion in a direction away from the first edge, and / or, the second edge connecting grid line is offset relative to the center line of the second edge connecting portion in a direction away from the second edge. In a second direction, the first edge sub-grid line is offset relative to the center line of the first edge extension portion in a direction away from the third edge, and / or, the second edge sub-grid line is offset relative to the center line of the second edge extension portion in a direction away from the fourth edge.

[0007] Beneficial effects: The outermost edge connecting grid lines on both sides of the battery along the first direction are offset towards the center line of their lower edge connecting portions relative to the center line of the battery's lower edge connecting portion. Similarly, the outermost edge sub-grid lines on both sides of the battery along the second direction are also offset towards the center line of their lower edge extension portions relative to the center line of the battery's lower edge extending portion. In other words, the outermost grid lines of the battery are offset inwards relative to their lower passivation contact structure, while the grid lines in the middle region are all located in the middle position of their lower passivation contact structure. This ensures that during grid line printing, the edge grid lines on the edge passivation contact structure are relatively close to the inwards, which helps improve printing accuracy and yield, prevents grid lines from being printed to the outside of the battery, and results in a larger overall space window. Secondly, due to the phenomenon of plating around the grid lines during the coating process, the grid lines in the edge region may not form effective ohmic contacts during the subsequent annealing and sintering process. This disclosure, by offsetting the edge grid lines inwards, can greatly reduce the occurrence of such defects.

[0008] In one optional embodiment, the grid structure further includes a plurality of main grid lines located between the first edge connecting grid line and the second edge connecting grid line, the main grid lines being disposed on the intermediate connecting portion.

[0009] Beneficial effects: The above-mentioned asymmetric edge structure design is applicable to both grid-connected and gridless cells, greatly expanding its scope of application.

[0010] In one alternative implementation, the width of the first edge connecting gate line and the second edge connecting gate line in the first direction is greater than the width of the sub-gate line in the second direction.

[0011] Beneficial effects: This design further ensures the carrier collection efficiency of the edge-connected grid lines, improving the photoelectric conversion efficiency of the battery.

[0012] In one alternative implementation, the width of the first edge extension and / or the second edge extension in the second direction is greater than the width of the intermediate extension in the second direction.

[0013] Beneficial effects: The width of the edge extensions on both sides along the second direction in the battery is set to be greater than that of the conventional extension in the middle region, i.e., the middle extension. This helps to widen the carrier collection area of ​​the passivation contact structure in the edge region, while also reducing the probability of edge leakage.

[0014] In one alternative embodiment, the width of the first edge extension in the second direction is not equal to the width of the second edge extension in the second direction.

[0015] Beneficial effects: It further enhances the asymmetry of the edge structure in the second direction, reduces the performance impact of battery caused by unilateral defects, and improves battery stability and service life.

[0016] In one alternative embodiment, a first edge sealing area is provided between the first edge connecting portion and the first edge, and a second edge sealing area is provided between the second edge connecting portion and the second edge, the base layer of the exposed portion of the first edge sealing area and the second edge sealing area, and the widths of the first edge sealing area and the second edge sealing area in a first direction are equal or unequal.

[0017] Beneficial effects: The first and second sealing regions can be the areas where the substrate layer is exposed after the passivation contact film layer is removed from the outer edges opposite each other in the first direction. This can effectively avoid leakage problems in the edge areas. The widths of the first and second sealing regions on the short side can be set to be equal or unequal. When equal, a uniformly distributed electric field can be formed, preventing single-sided edge breakdown. It also helps ensure stress balance on both sides, reducing the risk of cracking and improving structural stability. When unequal, it provides process tolerance, reduces the difficulty of structural fabrication, and allows for the repair of single-sided defects in the battery by adjusting the width of the sealing region on one side, ensuring overall performance.

[0018] In one alternative embodiment, an isolation region is provided between any adjacent passivated contact structures of different polarities; the width of the first sealing region and the second sealing region in the first direction is less than the width of the isolation region in the second direction, and the width of the first sealing region and the second sealing region in the first direction is greater than the width of the isolation region in the first direction.

[0019] Beneficial effects: The widths of the first and second sealing regions are both smaller than the width of the isolation region in the second direction, but larger than the width of the isolation region in the first direction. This ensures that leakage at the isolation edge is prevented while maximizing the preservation of the effective light-receiving area of ​​the solar cell. The sufficiently large width between adjacent extensions in the isolation region helps to form an absolute insulation channel, reducing the risk of short circuits in the battery due to process errors. The relatively small distance W6 between the extension and its adjacent connection part helps to increase the length of the extension and the length of the grid lines on it, thereby improving the carrier collection efficiency, while ensuring the isolation effect.

[0020] In one alternative embodiment, a third sealing region is provided between the first edge extension and the third edge, and a fourth sealing region is provided between the second edge extension and the fourth edge, the base layer of the third and fourth sealing regions being exposed, and the widths of the third and fourth sealing regions being unequal in the second direction.

[0021] Beneficial effects: The widths of the third and fourth sealing regions in the second direction are not equal. The width of the sealing region on the long side of the battery determines the risk of edge short circuit leakage of the overall battery. The asymmetrical design can effectively balance the effective collection of edge carriers and the risk of edge leakage.

[0022] In one alternative implementation, an isolation region is provided between any adjacent passivated contact structures of different polarities; at least one of the third and fourth sealing regions has a width in the second direction that is smaller than the width of the isolation region in the second direction, but larger than the width of the isolation region in the first direction.

[0023] Beneficial effects: It helps to widen the carrier collection area of ​​the passivated contact structure on the long edge, while reducing the probability of edge leakage.

[0024] In one alternative implementation, in a first direction, connecting portions of different polarities are arranged alternately; the first edge connecting portion and the second edge connecting portion have opposite polarities.

[0025] Beneficial effects: The first and second edge connection portions, which are opposite to each other in the first direction, have opposite polarities. Correspondingly, the first and second edge connection grid lines also have opposite polarities. The opposite polarities of the outermost edge connection portions on both sides of the battery in the first direction ensure that the number of passivation contact structures of different polarities in the battery is equal, preventing a significant difference in collection efficiency for charge carriers of different polarities caused by both passivation contact structures having the same polarity.

[0026] In one alternative implementation, in the second direction, extensions of different polarities are arranged alternately; the first edge extension and the second edge extension have opposite or the same polarity.

[0027] Beneficial effects: Opposite polarities help to further balance carrier collection, improving battery stability and lifespan; the same polarity is set on the edge extensions on the top and bottom edges and the edge sub-gate lines thereon, which helps to reduce the difficulty of process fabrication and improve the overall stability of the battery.

[0028] Secondly, this disclosure also provides a back-contact solar cell module, comprising: a plurality of the aforementioned back-contact solar cells. Attached Figure Description

[0029] To more clearly illustrate the technical solutions in the specific embodiments of this disclosure or the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this disclosure. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0030] Figure 1 This is a schematic diagram of the back-contact solar cell according to the doping type, representing an embodiment of the present disclosure. Figure 2 This is a schematic diagram showing the positional distribution of a back-contact solar cell in an embodiment of this disclosure when it is a gridless cell. Figure 3 This is a schematic diagram showing the positional distribution of a back-contact solar cell in an embodiment of this disclosure when it is a cell with a main grid. Figure 4This is another structural schematic diagram showing the positional distribution of the back-contact solar cell in an embodiment of this disclosure when it is a cell with a main grid. Figure 5 This is a microscope schematic diagram of the back-contact solar cell at the first edge according to an embodiment of the present disclosure; Figure 6 A microscope schematic diagram of the second edge of a back-contact solar cell according to an embodiment of this disclosure; Figure 7 This is a microscope illustration of the back-contact solar cell at the third edge according to an embodiment of the present disclosure; Figure 8 This is a microscope schematic diagram of the back-contact solar cell at the fourth edge according to an embodiment of the present disclosure.

[0031] Explanation of reference numerals in the attached figures: 1. Basal layer; 101. First edge; 102. Second edge; 103. Third edge; 104. Fourth edge; 2. Passivated contact structure; 201. Connecting portion; 2011. First edge connecting portion; 2012. Second edge connecting portion; 2013. Middle connecting portion; 202. Extension portion; 2021. First edge extension portion; 2022. Second edge extension portion; 2023. Middle extension portion; 21. First passivated contact structure; 211. First connecting portion; 212. First extension portion; 22. Second passivated contact structure; 221. Second connecting portion; 222. Second extension portion; 3. Gate line structure; 3011, First edge connecting gate line; 3012, Second edge connecting gate line; 3013, Main gate line; 302, Sub-gate line; 3021, First edge sub-gate line; 3022, Second edge sub-gate line; 3023, Middle sub-gate line; 31, First gate line structure; 311, First main gate line; 312, First sub-gate line; 32, Second gate line structure; 321, Second main gate line; 322, Second sub-gate line; 401. First border sealing area; 402. Second border sealing area; 403. Third border sealing area; 404. Fourth border sealing area; 5. Isolation area. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of the embodiments of this disclosure clearer, the technical solutions of the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this disclosure, and not all embodiments. Based on the embodiments of this disclosure, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this disclosure.

[0033] like Figures 1 to 8As shown, this disclosure discloses a back-contact solar cell, comprising: a substrate layer 1, a passivation contact structure 2, and a grid structure 3. The substrate layer 1 includes a light-receiving surface and a back-lighting surface opposite each other along the thickness direction, and further includes a first edge 101 and a second edge 102 opposite each other along a first direction and a third edge 103 and a fourth edge 104 opposite each other along a second direction in a plane perpendicular to the thickness direction, wherein the first direction and the second direction are perpendicular. The passivation contact structure 2 is formed on the back-lighting surface of the substrate layer 1, and includes a plurality of connecting portions 201 spaced apart along the first direction and a plurality of extension portions 202 spaced apart along the second direction. One end of the extension portion 202 is connected to the connecting portion 201. The plurality of connecting portions 201 include at least a first edge connecting portion 2011 adjacent to the first edge 101, a second edge connecting portion 2012 adjacent to the second edge 102, and a portion located between the first edge connecting portion 2011 and the second edge connecting portion 2012. The multiple intermediate connecting portions 2013 and multiple extension portions 202 include a first edge extension portion 2021 adjacent to the third edge 103, a second edge extension portion 2022 adjacent to the fourth edge 104, and multiple intermediate extension portions 2023 located between the first edge extension portion 2021 and the second edge extension portion 2022; the grid structure 3 includes at least a first edge connecting grid line 3011, a second edge connecting grid line 3012, and multiple sub-grid lines 302. The first edge connecting grid line 3011 is disposed on the first edge connecting portion 2011, the second edge connecting grid line 3012 is disposed on the second edge connecting portion 2012, and the multiple sub-grid lines 302 include a first edge sub-grid line 3021 disposed on the first edge extension portion 2021, a second edge sub-grid line 3022 disposed on the second edge extension portion 2022, and multiple intermediate sub-grid lines 3023 disposed on the intermediate extension portions 2023.

[0034] Specifically, the substrate 1 can be a silicon substrate. On one hand, the substrate 1 includes a light-receiving surface and a back-lighting surface in the thickness direction. A passivation contact structure 2 and a gate line structure 3 are disposed on the back-lighting surface. The passivation contact structure 2 can be a tunneling oxide layer and a doped polycrystalline silicon layer of a TOPCon cell, or an intrinsic amorphous silicon layer and a doped amorphous silicon layer of a heterojunction cell, or a passivation contact film layer of other cell types, without specific limitations. On the other hand, such as Figures 1 to 4 As shown, the substrate layer 1 includes a first edge 101, a second edge 102, a third edge 103, and a fourth edge 104 in a plane perpendicular to the thickness direction. The first edge 101 and the second edge 102 are opposite each other along a first direction, and the third edge 103 and the fourth edge 104 are opposite each other along a second direction. The sides containing the first edge 101 and the second edge 102 are the short sides of the battery, and the sides containing the third edge 103 and the fourth edge 104 are the long sides of the battery.

[0035] like Figure 1As shown, the passivation contact structure 2 can be divided into a first passivation contact structure 21 and a second passivation contact structure 22 according to the doping type. One of them is p-type doped and the other is n-type doped. The first passivation contact structure 21 includes a first connecting portion 211 and a plurality of first extension portions 212. The second passivation contact structure 22 includes a second connecting portion 221 and a plurality of second extension portions 222. The first connecting portion 211 and the second connecting portion 221 are arranged alternately along a first direction. Between the first connecting portion 211 and the second connecting portion 221, the first extension portions 212 and the second extension portions 222 are arranged alternately. One end of the plurality of first extension portions 212 is connected to the first connecting portion 211, and one end of the plurality of second extension portions 222 is connected to the second connecting portion 221. Thus, the first passivation contact structure 21 and the second passivation contact structure 22 with different doping types are arranged in an interdigitated pattern. A groove-shaped isolation region 5 is formed between the first passivation contact structure 21 and the second passivation contact structure 22. Accordingly, the gate line structure 3 is divided into a first gate line structure 31 and a second gate line structure 32 with opposite conductivity types. The first gate line structure 31 is disposed on the first passivation contact structure 21 and includes a first main gate line 311 disposed on the first connection portion 211 and a first sub-gate line 312 disposed on the first extension portion 212. The second gate line structure 32 is disposed on the second passivation contact structure 22 and includes a second main gate line 321 disposed on the second connection portion 221 and a second sub-gate line 322 disposed on the second extension portion 222. The doping type of the edge connection portion is opposite to the doping type of the adjacent intermediate connection portion, and the conductivity type of the edge gate line is opposite to the conductivity type of the adjacent main gate line.

[0036] like Figures 2 to 4 As shown, the passivation contact structure 2 can be divided into edge passivation contact structure and intermediate passivation contact structure based on its positional distribution. Depending on the different edges of the substrate layer 1, the edge passivation contact structure includes a first edge connecting portion 2011 and a second edge connecting portion 2012 opposite each other in a first direction, and a first edge extension portion 2021 and a second edge extension portion 2022 opposite each other in a second direction. The first edge connecting portion 2011 and the second edge connecting portion 2012 are close to the short side of the battery and extend along the second direction, while the first edge extension portion 2021 and the second edge extension portion 2022 are close to the long side of the battery and extend along the first direction. The intermediate passivation contact structure includes multiple intermediate connecting portions 2013 and multiple intermediate extension portions 2023. The intermediate connecting portions 2013 are located between the first edge connecting portions 2011 and the second edge connecting portions 2012 and extend along the second direction; the intermediate extension portions 2023 are located between the first edge extension portions 2021 and the second edge extension portions 2022 and extend along the first direction.

[0037] like Figure 2As shown, in some embodiments, the back-contact solar cell of this disclosure is a gridless solar cell, that is, no main grid line is provided on the middle connection portion 2013, only edge connection grid lines are provided on the edge connection portion and sub-grid lines 302 are provided on the extension portion 202.

[0038] like Figure 3 and Figure 4 As shown, in some other embodiments, the back-contact solar cell of this disclosure is a solar cell with a main grid, that is, the grid structure 3 further includes a plurality of main grid lines 3013 located between the first edge connecting grid line 3011 and the second edge connecting grid line 3012, and the main grid lines 3013 are disposed on the intermediate connecting portion 2013. That is, the grid structure 3 includes the main grid lines 3013 disposed on the intermediate connecting portion 2013, the edge connecting grid lines disposed on the edge connecting portion, and the sub-grid lines 302 disposed on the extension portion 202.

[0039] For ease of explanation, the following description uses a back-contact solar cell with a main grid as an example, and elaborates on the asymmetric design of the edge structure at various levels: like Figures 2 to 8 As shown, in some embodiments, in a first direction, the first edge connecting gate line 3011 is offset relative to the center line of the first edge connecting portion 2011 in a direction away from the first edge 101, and the second edge connecting gate line 3012 is offset relative to the center line of the second edge connecting portion 2012 in a direction away from the second edge 102; in a second direction, the first edge sub-gate line 3021 is offset relative to the center line of the first edge extension portion 2021 in a direction away from the third edge 103, and the second edge sub-gate line 3022 is offset relative to the center line of the second edge extension portion 2022 in a direction away from the fourth edge 104.

[0040] Specifically, the outermost edge connecting grid lines on both sides of the battery along the first direction are offset towards the center line of their lower edge connecting portions relative to the center line of the battery's lower edge connecting portion. Similarly, the outermost edge sub-grid lines on both sides of the battery along the second direction are also offset towards the center line of their lower edge extension portions relative to the center line of the battery's lower edge extending portion. That is, the outermost grid lines of the battery are all offset inward relative to their lower passivation contact structure, while the grid lines in the middle region can all be located in the middle position of their lower passivation contact structure. In this way, during the grid line printing process, the edge grid lines on the edge passivation contact structure are relatively close to the inward side, which helps to improve printing accuracy and yield, prevents grid lines from being printed to the outside of the battery, and has a larger overall space window. Secondly, due to the phenomenon of plating around the coating during the coating process, the grid lines in the edge region may not form an effective ohmic contact in the subsequent annealing and sintering process. The present disclosure offsets the edge grid lines inward, which can greatly reduce the occurrence of such defects.

[0041] Of course, some of the first edge connecting grid line 3011, the second edge connecting grid line 3012, the first edge sub-grid line 3021 and the second edge sub-grid line 3022 can be offset inwards, while the other parts can be set at the center position.

[0042] In some embodiments, such as Figure 5 and Figure 6 As shown, the width of the first edge connecting gate line 3011 and the second edge connecting gate line 3012 in the first direction is greater than the width of the sub-gate line 302 in the second direction, which further ensures the carrier collection efficiency of the edge connecting gate line and improves the photoelectric conversion efficiency of the battery.

[0043] like Figures 2 to 4 as well as Figure 7 and Figure 8 As shown, in some embodiments, the width of the first edge extension 2021 and the second edge extension 2022 in the second direction is greater than the width of the middle extension 2023 in the second direction.

[0044] That is, the width of the edge extensions on both sides of the battery along the second direction is set to be greater than that of the conventional extension in the middle region, i.e., the middle extension 2023. This helps to widen the carrier collection area of ​​the passivated contact structure in the edge region, while reducing the probability of edge leakage.

[0045] Similarly, the width of either the first edge extension 2021 or the second edge extension 2022 can be set to be greater than the width of the middle extension 2023.

[0046] Furthermore, in some embodiments, the width of the first edge extension 2021 in the second direction may be different from the width of the second edge extension 2022 in the second direction, further enhancing the asymmetry of the edge structure in the second direction, reducing the performance impact of the battery due to unilateral defects, and improving battery stability and service life.

[0047] like Figures 2 to 5 As shown, a first edge sealing area 401 is provided between the first edge connecting portion 2011 and the first edge 101, and a second edge sealing area 402 is provided between the second edge connecting portion 2012 and the second edge 102. The base layer 1 of the exposed portion of the first edge sealing area 401 and the second edge sealing area 402 has equal or unequal widths in the first direction.

[0048] The first sealing region 401 and the second sealing region 402 can be the areas where the base layer 1 is exposed after the passivation contact film layer is removed from the outer edges opposite each other in the first direction. This can effectively avoid leakage problems in the edge region. The widths W1 of the first sealing region 401 and W2 of the second sealing region 402 on the short side can be set to be equal or unequal. When the widths W1 of the first sealing region 401 and W2 of the second sealing region 402 are equal, a uniformly distributed electric field can be formed, preventing single-sided edge breakdown. Furthermore, it helps ensure stress balance on both sides of the edge, reducing the risk of cracking and improving structural stability. When the widths W1 of the first sealing region 401 and W2 of the second sealing region 402 are unequal, it provides process tolerance, reduces the difficulty of structural fabrication, and allows for the repair of single-sided defects in the battery by adjusting the width of the sealing region on one side when edge leakage occurs on one side, ensuring overall performance.

[0049] In the aforementioned back-contact solar cell, there is an isolation space between any two adjacent intermediate extensions 2023 and between the intermediate extension 2023 and its adjacent edge extension 202, thereby forming an isolation region 5. The distance between any two adjacent intermediate extensions 2023 is the width W5 of the isolation region 5 in the second direction, and the distance between the intermediate extension 2023 and its adjacent connecting portion is the width W6 of the isolation region in the first direction.

[0050] In some embodiments, such as Figures 3 to 6 As shown, the width of the first sealing area 401 and the second sealing area 402 in the first direction is less than the width of the isolation area 5 in the second direction, and the width of the first sealing area 401 and the second sealing area 402 in the first direction is greater than the width of the isolation area 5 in the first direction.

[0051] That is, the width W1 of the first sealing area 401 and the width W2 of the second sealing area 402 are both smaller than the width W5 of the isolation area 5 in the second direction, and larger than the width W6 of the isolation area in the first direction. This ensures that leakage at the isolation edge is prevented while maximizing the preservation of the effective light-receiving area of ​​the solar cell. The width W5 between adjacent extensions 202 in the isolation area 5 is set large enough to help form an absolute insulation channel and reduce the risk of short circuits in the battery due to process errors. The distance W6 between the extension 202 and its adjacent connection 201 is relatively small. Under the premise of ensuring the isolation effect, a smaller distance also helps to increase the length of the extension 202 and the length of the grid lines on it, thereby improving the carrier collection efficiency.

[0052] Similarly, in some embodiments, such as Figures 2 to 4 as well as Figure 7 and Figure 8As shown, a third edge sealing area 403 is provided between the first edge extension 2021 and the third edge 103, and a fourth edge sealing area 404 is provided between the second edge extension 2022 and the fourth edge 104. The base layer 1 is exposed in the third edge sealing area 403 and the fourth edge sealing area 404, and the widths of the third edge sealing area 403 and the fourth edge sealing area 404 are not equal in the second direction.

[0053] In this disclosure, the widths W3 of the third sealing region 403 and W4 of the fourth sealing region 404 in the second direction are not equal. The width of the sealing region on the long side of the battery determines the risk of edge short circuit leakage of the overall battery. By designing it asymmetrically, the effective collection of edge carriers and the risk of edge leakage can be effectively balanced.

[0054] Furthermore, at least one of the third sealing region 403 and the fourth sealing region 404 has a width in the second direction that is smaller than the width of the isolation region 5 in the second direction, but larger than the width W6 of the isolation region 5 in the first direction. This design helps to widen the carrier collection area of ​​the passivated contact structure on the long edge, while reducing the probability of edge leakage. (Reference) Figure 7 and Figure 8 In this disclosure, the width W3 of the third sealing area 403 is less than the width W5 of the isolation area 5 but greater than the width W6 of the isolation area 5 in the first direction, while the width W4 of the fourth sealing area 404 is greater than the width W5 of the isolation area 5.

[0055] like Figures 1 to 4 As shown, in the aforementioned back-contact solar cell, in the first direction, connecting portions 201 of different polarities are arranged alternately; in the second direction, extension portions 202 of different polarities are arranged alternately.

[0056] Based on this, in some embodiments, the first edge connection portion 2011 and the second edge connection portion 2012, which are opposite in the first direction, have opposite polarities. Correspondingly, the first edge connection grid line and the second edge connection grid line also have opposite polarities. The opposite polarities of the outermost edge connection portions on both sides of the battery in the first direction ensure that the number of passivation contact structures of different polarities in the battery is equal, preventing a large difference in collection efficiency for charge carriers of different polarities caused by both passivation contact structures having the same polarity.

[0057] In one alternative embodiment, such as Figure 2 and Figure 3 As shown, the first edge extension 2021 and the second edge extension 2022, which are opposite to each other in the second direction, have opposite polarities, further balancing carrier collection and improving battery stability and lifespan.

[0058] In another alternative embodiment, such as Figure 4As shown, the first edge extension 2021 and the second edge extension 2022, which are opposite each other in the second direction, have the same polarity, which reduces the difficulty of the manufacturing process.

[0059] This disclosure also provides a back-contact solar cell module, including: a plurality of the above-described back-contact solar cells, which improves the overall power generation efficiency at the module end.

[0060] Further functional descriptions of the above structures are the same as those of the corresponding embodiments described above, and will not be repeated here.

[0061] Although embodiments of the present disclosure have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the present disclosure, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A back-contact solar cell, characterized in that, include: The substrate layer includes a light-receiving surface and a backlight surface that are opposite each other along the thickness direction; it also includes a first edge and a second edge that are opposite each other along a first direction in a plane perpendicular to the thickness direction, and a third edge and a fourth edge that are opposite each other along a second direction, wherein the first direction and the second direction are perpendicular to each other. A passivated contact structure is formed on the backlight surface of the substrate layer; the passivated contact structure includes a plurality of connecting portions spaced apart along a first direction and a plurality of extension portions spaced apart along a second direction, one end of the extension portion being connected to the connecting portion; the plurality of connecting portions includes at least a first edge connecting portion adjacent to the first edge, a second edge connecting portion adjacent to the second edge, and a plurality of intermediate connecting portions located between the first edge connecting portion and the second edge connecting portion; the plurality of extension portions includes a first edge extension portion adjacent to the third edge, a second edge extension portion adjacent to the fourth edge, and a plurality of intermediate extension portions located between the first edge extension portion and the second edge extension portion. The grid structure includes at least a first edge connecting grid line, a second edge connecting grid line, and a plurality of sub-grid lines. The first edge connecting grid line is disposed on the first edge connecting portion, the second edge connecting grid line is disposed on the second edge connecting portion, and the plurality of sub-grid lines include a first edge sub-grid line disposed on the first edge extension portion, a second edge sub-grid line disposed on the second edge extension portion, and a plurality of intermediate sub-grid lines disposed on the intermediate extension portion. In the first direction, the first edge connecting gate line is offset relative to the center line of the first edge connecting portion in a direction away from the first edge, and / or, the second edge connecting gate line is offset relative to the center line of the second edge connecting portion in a direction away from the second edge; and / or, in the second direction, the first edge sub-gate line is offset relative to the center line of the first edge extension in a direction away from the third edge, and / or, the second edge sub-gate line is offset relative to the center line of the second edge extension in a direction away from the fourth edge.

2. The back-contact solar cell according to claim 1, characterized in that, The grid structure further includes a plurality of main grid lines located between the first edge connecting grid line and the second edge connecting grid line, the main grid lines being disposed on the intermediate connecting portion.

3. The back-contact solar cell according to claim 1, characterized in that, The width of the first edge connecting gate line and the second edge connecting gate line in the first direction is greater than the width of the sub-gate line in the second direction.

4. The back-contact solar cell according to claim 1, characterized in that, The width of the first edge extension and / or the second edge extension in the second direction is greater than the width of the middle extension in the second direction.

5. The back-contact solar cell according to claim 1 or 4, characterized in that, The width of the first edge extension in the second direction is not equal to the width of the second edge extension in the second direction.

6. The back-contact solar cell according to claim 1, characterized in that, A first edge sealing area is provided between the first edge connecting portion and the first edge, and a second edge sealing area is provided between the second edge connecting portion and the second edge. The base layer is exposed in the first edge sealing area and the second edge sealing area. The widths of the first edge sealing area and the second edge sealing area are equal or unequal in the first direction.

7. The back-contact solar cell according to claim 6, characterized in that, An isolation region exists between any adjacent passivated contact structures of different polarities; The width of the first edge sealing area and the second edge sealing area in the first direction is less than the width of the isolation area in the second direction, and the width of the first edge sealing area and the second edge sealing area in the first direction is greater than the width of the isolation area in the first direction.

8. The back-contact solar cell according to claim 1, characterized in that, A third sealing area is provided between the first edge extension and the third edge, and a fourth sealing area is provided between the second edge extension and the fourth edge. The base layer is exposed in the third and fourth sealing areas, and the widths of the third and fourth sealing areas are not equal in the second direction.

9. The back-contact solar cell according to claim 8, characterized in that, An isolation region is provided between any adjacent passivated contact structures of different polarities; at least one of the third sealing region and the fourth sealing region has a width in the second direction that is smaller than the width of the isolation region in the second direction and larger than the width of the isolation region in the first direction.

10. The back-contact solar cell according to claim 1, characterized in that, In the first direction, connecting portions of different polarities are arranged alternately; the first edge connecting portion and the second edge connecting portion have opposite polarities.

11. The back-contact solar cell according to claim 1, characterized in that, In the second direction, extensions of different polarities are arranged alternately; the first edge extension and the second edge extension have opposite or the same polarity.

12. A back-contact solar cell module, characterized in that, include: The back-contact solar cell according to any one of claims 1-11.

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