Back contact solar cell and cell assembly

Abstract

This disclosure relates to the field of solar cell technology, and discloses a back-contact solar cell and a cell module. A first doped structure and a second doped structure are alternately formed on the back surface of a substrate. The first doped structure includes a first busbar and a first extension, and the second doped structure includes a second busbar and a second extension. The width of the first extension is W1, and the width of the second extension is W2, the sum of which is a constant W. An edge doped structure is connected to the busbar closest to the edge of the substrate, and includes an exit region and a connection region. The width of the connection region in a second direction ranges from (a, W), where a = min(W1, W2) or a = W1 = W2. The first extension and the second extension of this disclosure have different widths, and the width of the connection region is greater than the smaller of the two and less than or equal to the larger of the two, balancing carrier transport efficiency and passivation performance, thereby improving cell yield and power generation efficiency.

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 are a type of solar cell technology that moves the front-side grid lines to the back side, avoiding light loss caused by the front-side grid lines. Since grid lines of different polarities are located on the back side of the cell, the overall doped region and grid line patterning design on the back side of the cell are particularly important in the back-contact solar cell manufacturing process. In particular, to improve carrier collection and transport, the design of the doped region, which is an important component of the cell substrate and is used to generate holes and electron carriers, needs to be optimized and improved first.

[0003] In related technologies, back-contact solar cells typically have alternating p-type and n-type doped regions on the back side, along with an isolation region between them. Currently, the passivation and contact performance of p-poly films are generally lower than those of n-poly films, and it is difficult to significantly optimize the corresponding processes. To further balance the performance differences between p and n regions at the end of the cell, their corresponding area ratio is one of the factors that urgently needs to be optimized during the patterning design process. Summary of the Invention

[0004] This disclosure provides a back-contact solar cell and a cell module to solve the problem that unreasonable design of the doped region area in existing back-contact solar cells affects grid line printing and cell performance, thereby affecting the cell's power generation efficiency.

[0005] In a first aspect, this disclosure provides a back-contact solar cell, comprising: a substrate layer, at least one set of first doped structures and second doped structures, and an edge doped structure. The substrate layer includes a light-receiving surface and a back-lighting surface disposed opposite to each other. The first doped structures and the second doped structures are spaced apart on the back-lighting surface of the substrate layer and have opposite conductivity types. The first doped structure includes a first busbar and a plurality of first extensions connected together, and the second doped structure includes a second busbar and a plurality of second extensions connected together. The first busbar and the second busbar are spaced apart along a first direction, and the first extensions and the second extensions alternate between the first busbar and the second busbar along a second direction. The arrangement is as follows: the width of the first extension in the second direction is W1, the width of the second extension in the second direction is W2, and the sum of the widths of the first extension and the second extension in the second direction is a certain value W; the edge doped structure is connected to the busbar closest to the edge of the substrate layer in the first direction and has the same conductivity type as the busbar; the edge doped structure includes a lead-out region and a connection region; the lead-out region is suitable for setting pads; the connection region connects the busbar and the lead-out region; the width of the connection region in the second direction is W3, and the range of W3 is (a, W), where when W1≠W2, a=min(W1, W2), and when W1=W2, a=W1=W2.

[0006] Beneficial effects: The back-contact solar cell disclosed herein designs the area ratio of the first doped structure and the second doped structure with different conductivity types to balance the cell's carrier transport performance and passivation performance. Based on this, the width of the connection region is adaptively set. Taking the width of the first extension and the second extension with the same width as the reference, when the width of the extension of the outermost doped structure is narrowed relative to the reference, the width of the connection region with the same conductivity type can remain unchanged, that is, it can maintain the same width as the extension with different polarities. The connection region can also be further widened relative to the reference to ensure that its width is sufficiently greater than the width of the narrowed extension, but less than the sum of the widths of the first extension and the second extension, so as to ensure the function of the adjacent extension with another conductivity type. Of course, the width of the connection region can also be slightly narrowed relative to the reference, but it should be greater than the width of the narrowed extension, that is, the degree of narrowing is smaller than that of the extension. In short, when the extension of the outermost doped structure with the same conductivity type as the connection region is narrowed, the width of the connection region is always greater than the width of the narrowed extension, but less than the sum of the widths of the first extension and the second extension. When the extension of the doped structure at the outermost edge is widened relative to the reference reference, the width of the connection region with the same conductivity type can be consistent with the width of the widened extension. This facilitates the fabrication of wider gate lines with lower line resistance, thereby improving the output efficiency of the bus current in the connection region. Alternatively, the width of the connection region can be slightly smaller than the width of the widened extension but larger than the width of the extension of another conductivity type, so as to relatively increase the width of the extension of another conductivity type and ensure that it still has sufficient width to achieve carrier collection. Or, the width of the connection region can be slightly larger than the width of the widened extension but smaller than the sum of the widths of the first and second extensions, ensuring that the width of the connection region is the largest compared to other regions, thereby maximizing the output efficiency of the bus current in the gate lines set thereon.

[0007] In other words, this disclosure first designs the area ratio, i.e., the width, of the first extension and the second extension differently. Based on this, if the widths of the first extension and the second extension are different, the width of the connection region is greater than the smaller of the two widths but less than the sum of their widths; if the two widths are equal, the width of the connection region is greater than the equal width but less than the sum of their widths. This makes the width of the connection region different from the widths of the first extension and the second extension in the doped structure, taking into account both the carrier transport efficiency and passivation performance on the back surface of the substrate. At the same time, the relatively increased width of the connection region can also ensure the printing accuracy of the gate line paste on it. The increased gate line width reduces the line resistance, and the larger current flowing through it can be output efficiently, thereby improving the overall battery yield and power generation efficiency.

[0008] In one optional embodiment, the ratio of the width W1 of the first extension in the second direction to the width W2 of the second extension in the second direction is in the range of 1:1 to 3:1.

[0009] Beneficial effects: In this disclosure, the sum of the widths of the first extension and the second extension is a certain value W, which can be a ratio of the width of the p-type extension to the width of the n-type extension in the range of 1:1 to 3:1, or a ratio of the width of the n-type extension to the width of the p-type extension in the range of 1:1 to 3:1. That is, the width of the p-type extension can be greater than or less than the width of the n-type extension within the above range. Of course, the widths of the two can also be equal, thereby optimizing the different battery structures to meet the requirements of both carrier transport performance and passivation performance, and providing more application possibilities for the component.

[0010] In one alternative implementation, the width W3 of the connecting area in the second direction ranges from (1 / 2W, W).

[0011] Beneficial effects: Under the premise that the sum of the widths of the first extension and the second extension is a certain value W, the width W3 of the connection area is greater than half of the fixed value W and less than the fixed value W. Regardless of the conductivity type of the connection area, it is always ensured that the width of the connection area is increased compared to the reference width, which improves the carrier transport performance when connecting the current collection area and the lead-out area. More importantly, it has sufficient width to further solve the printing accuracy problem of the grid line paste, reduce the line resistance of the grid line, improve the current output efficiency and the overall battery yield.

[0012] In one alternative implementation, the width W3 of the connection region in the second direction ranges from 100 to 800 μm.

[0013] Beneficial effects: It facilitates the formation of the overall doped structure in the connection area and on the backlight surface, and ensures that the width of the connection area matches the overall doped structure design.

[0014] In one optional embodiment, it further includes: a corner doped structure located in a first direction between the lead-out region and the busbar closest to the edge of the substrate layer; the corner doped structure includes a first portion and a second portion, the first portion extending along the first direction and spaced apart from the connection region, the second portion extending along a second direction, and one end of the second portion being connected to the end of the first portion relatively close to the lead-out region, and the other end of the second portion being connected to an extension with a conductivity type opposite to that of the connection region.

[0015] Beneficial effects: This disclosure further designs the "extension" located between the lead-out region and the busbar to form a corner doped structure including a first section and a second section. The first section is arranged parallel to the extension, and the second section connects the first section with another extension located on the side of the first section away from the connection region. However, in this disclosure, the connection between the second section and the other extension is moved inward compared to the conventional scheme, making it closer to the lead-out region. Under the premise of ensuring that the area of ​​the doped region remains unchanged, the grid lines formed on it can have a shorter carrier transport and collection path, thereby improving the power generation efficiency of the battery.

[0016] In one alternative embodiment, the ratio of the width W4 of the first portion of the corner doped structure in the second direction to the width W3 of the connecting region in the second direction is in the range of 4:1 to 1:20.

[0017] Beneficial effects: The width of the first segment, which extends in the same direction as the connection region, can be greater than or less than the width of the connection region. Based on the width design of the connection region and the width of the adjacent extensions that are consistent with the conductivity type of the connection region, the width of the first segment is set within the above-mentioned ratio range to ensure that the doping regions of the connection region and the first segment and other extensions in the entire region are coordinated and matched, thereby optimizing the doping performance to improve passivation performance and carrier transport.

[0018] In one alternative implementation, the two first portions located on either side of the connecting area in the second direction have different widths, and the sum of the width W4 of one of the first portions in the second direction and the width W3 of the connecting area in the second direction is a constant value W.

[0019] Beneficial effect: The sum of the width of the first section and the width of the connection region is also a certain value. In this way, while meeting the width requirements of the connection region, the width of the first section must also be adjusted accordingly to ensure the stability of the doped structure and the carrier transport performance in the edge region.

[0020] In one alternative implementation, it further includes: The first gate line is disposed on the first doped structure; The second gate line is disposed on the second doped structure; A connecting grid line is disposed on the connecting area, and the width of the connecting grid line is greater than the width of the first grid line and the second grid line. A pad is provided on the lead-out area, and a gate line connects the pad and the gate line at the outermost edge in the first direction.

[0021] Beneficial effects: The first gate line, the second gate line, and the connecting gate line can be formed by screen printing. The pads are set on the lead-out area and connected to the gate line located at the outermost edge of the substrate layer. That is, if the outermost edge is the first gate line, the pad is connected to the first gate line through the connecting gate line, which is used to output the charge carriers of the first doped structure and the edge doped structure with the same conductivity type; if the outermost edge is the second gate line, the pad is connected to the second gate line through the connecting gate line, which is used to output the charge carriers of the second doped structure and the edge doped structure with the same conductivity type.

[0022] In one alternative implementation, one of the first gate line and the second gate line is a p-type gate line and the other is an n-type gate line, wherein the width of the p-type gate line is greater than the width of the n-type gate line.

[0023] Beneficial effects: Since the carrier transport and collection performance of p-type doped structures is generally weaker than that of n-type doped structures, this disclosure designs the width of the gate line on the p-type doped structure to be greater than that on the n-type doped structure in order to improve the transport and collection of hole carriers.

[0024] Secondly, this disclosure also provides a back-contact solar cell module, comprising: a plurality of the aforementioned back-contact solar cells.

[0025] Beneficial effects: Back-contact solar cell modules include several of the aforementioned back-contact solar cells, possessing all the advantages of back-contact solar cells, optimizing the performance of individual cells to achieve significant efficiency optimization at the module level, and ultimately expanding the application of solar cell modules in different scenarios. Attached Figure Description

[0026] 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.

[0027] Figure 1 This is a schematic diagram of a doped structure of a back-contact solar cell according to an embodiment of the present disclosure; Figure 2 This is a schematic diagram of a back-contact solar cell according to an embodiment of the present disclosure; Figure 3 This is another schematic diagram of the doped structure of the back contact solar cell according to an embodiment of the present disclosure; Figure 4 This is a schematic diagram of another structure of a back-contact solar cell according to an embodiment of this disclosure; Figure 5This is a schematic diagram of a conventional back-contact solar cell.

[0028] Explanation of reference numerals in the attached figures: 1. Basal layer; 2. First doped structure; 201. First busbar; 202. First extension; 3. Second doped structure; 301. Second busbar; 302. Second extension; 4. Edge-doped structure; 401. Lead-out region; 402. Connecting region; 5. Corner doped structure; 501, First section; 502, Second section; 6. First grid line; 7. Second grid line; 8. Connect the grid lines; 9. Solder pads; A. Third extension; B. Fourth extension. Detailed Implementation

[0029] 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.

[0030] like Figures 1 to 4As shown, this disclosure provides a back-contact solar cell, comprising: a substrate layer 1, at least one set of first doped structures 2 and second doped structures 3, and an edge doped structure 4. The substrate layer 1 includes a light-receiving surface and a back-lighting surface disposed opposite to each other. The first doped structures 2 and 3 are formed alternately on the back-lighting surface of the substrate layer 1 and have opposite conductivity types. The first doped structure 2 includes a first busbar 201 connected to each other and a plurality of first extensions 202. The second doped structure 3 includes a second busbar 301 connected to each other and a plurality of second extensions 302. The first busbar 201 and the second busbar 301 are spaced apart along a first direction, and the first extensions 202 and the second extensions 302 alternate between the first busbar 201 and the second busbar 301 along a second direction. The components are arranged at intervals; the width of the first extension 202 in the second direction is W1, the width of the second extension 302 in the second direction is W2, and the sum of the widths of the first extension 202 and the second extension 302 in the second direction is a certain value W; the edge doped structure 4 is connected to the busbar closest to the edge of the substrate layer 1 in the first direction and has the same conductivity type as the busbar. The edge doped structure 4 includes a lead-out region 401 and a connection region 402. The lead-out region 401 is suitable for setting the pad 9. The connection region 402 connects the busbar and the lead-out region 401. The width of the connection region 402 in the second direction is W3, and the range of W3 is (a, W), where when W1≠W2, a=min(W1, W2), and when W1=W2, a=W1=W2.

[0031] Specifically, the substrate 1 can be a silicon substrate, which includes a light-receiving surface and a back-lighting surface disposed opposite to each other. The light-receiving surface receives incident sunlight, while the doped structure and gate lines are disposed on the back-lighting surface of the substrate 1. Figures 1 to 4 All views are top views from the backlight side. The first doped structure 2 and the second doped structure 3 are passivated contact structures spaced apart on the backlight side. For example, both the first doped structure 2 and the second doped structure 3 can be selected from a TOPCon cell type tunneling oxide layer and a doped polycrystalline silicon layer. In the first doped structure 2 and the second doped structure 3, one of them has an n-type conductivity and the other has a p-type conductivity. Multiple sets of the first doped structure 2 and the second doped structure 3 can be provided and arranged alternately along the first direction. Specifically, the first and second current-collecting regions extending along the second direction are alternately spaced in the second direction. In the area between any two adjacent sets of first and second current-collecting regions, multiple first extensions 202 and second extensions 302 extending along the first direction and alternately spaced along the second direction are provided. The sum of the width W1 of a single first extension 202 in the second direction and the width W2 of a single second extension 302 in the second direction is W. Figures 1 to 4Taking only a set of first doped structures 2 and second doped structures 3 located at the edge of substrate 1 as an example, the first direction is perpendicular to the second direction. The edge doped structure 4 is located between the set of first doped structures 2 and second doped structures 3 closest to the edge of substrate 1. Its lead-out region 401 is moved inward relative to the busbar region of the outermost doped structure, so that the pad 9 and the solder ribbon in the subsequent process can be set at a certain distance from the edge, thereby ensuring the reliability of the solder ribbon connection and the output of the charge carrier. The connection region 402 is used to transfer the charge carriers of the outermost doped structure to the lead-out region 401 and the solder ribbon. Based on the width design of the extension of different conductivity types in the doped structure, this disclosure makes the width of the connection region 402 correspondingly widened to ensure the charge carrier transmission efficiency and facilitate the subsequent printing and forming of the gate line on this region. The current in the gate line on the connection region 402 is a large busbar current. Therefore, widening the connection region 402 makes it easier to widen the gate line set on it, thereby reducing the line resistance of the gate line and ultimately improving the output efficiency of the busbar current and the power generation efficiency and yield of the battery.

[0032] In this disclosure, the area ratio of the first doped structure 2 and the second doped structure 3 with different conductivity types is designed to balance the charge carrier transport performance and passivation performance of the battery. For example, the first extension 202 of the first doped structure 2 and the second extension 302 of the second doped structure 3 have different widths. The width of the first extension 202 is W1, and the width of the second extension 302 is W2. Under the premise that the sum of the widths of the first extension 202 and the second extension 302 is a constant value W, if the area of ​​the p-type doped structure is greater than the area of ​​the n-type doped structure, that is, increasing the proportion of the p-type doped structure on the substrate layer 1 and correspondingly reducing the proportion of the n-type doped structure on the substrate layer 1, the number of carriers transported to the p-type doped structure in the substrate layer 1 can increase, thereby balancing the difference in transport performance between the p-type and n-type doped structures. If the area of ​​the n-type doped structure is greater than the area of ​​the p-type doped structure, that is, increasing the proportion of the n-type doped structure on the substrate layer 1 and correspondingly reducing the proportion of the p-type doped structure on the substrate layer 1, since the thin film performance of the n-type doped structure is better than that of the p-type doped structure, the area of ​​the n-type doped structure being greater than the area of ​​the p-type doped structure can increase the area of ​​the high-performance thin film on the back surface of the battery, thereby significantly improving the passivation performance of the battery.

[0033] Based on this, the width of the connection region 402 is adaptively set. Using the width of the first extension 202 and the second extension 302 being the same as the reference, when the width of the extension of the outermost doped structure is narrowed relative to the reference, the width of the connection region 402 with the same conductivity type does not need to be narrowed; that is, it maintains the same width as the extensions of different polarities. Figure 1As shown; the connection area 402 can also be further widened relative to the reference datum, such as Figure 3 As shown, its width is further ensured to be sufficiently greater than the width of the narrowed extension, but less than the sum of the widths of the first extension 202 and the second extension 302, to ensure the function of the adjacent extension of another conductivity type; of course, the width of the connection region 402 can also be slightly narrowed relative to the reference reference, but it should be greater than the width of the narrowed extension, that is, the degree of narrowing should be smaller than that of the extension. In short, when the extension of the doped structure of the outermost edge that is consistent with the conductivity type of the connection region 402 is narrowed, the width of the connection region 402 is always greater than the width of the narrowed extension, but less than the sum of the widths of the first extension 202 and the second extension 302. When the extension of the doped structure at the outermost edge is widened relative to the reference reference, the width of the connection region 402 with the same conductivity type can be consistent with the width of the widened extension. This facilitates the fabrication of wider gate lines with lower line resistance, thereby improving the output efficiency of the bus current in the connection region 402. Alternatively, the width of the connection region 402 can be slightly smaller than the width of the widened extension but larger than the width of the extension of another conductivity type, so as to relatively increase the width of the extension of another conductivity type and ensure that it still has sufficient width to achieve carrier collection. Or, the width of the connection region 402 can be slightly larger than the width of the widened extension but smaller than the sum of the widths of the first extension 202 and the second extension 302, ensuring that the width of the connection region 402 is the largest compared to other regions, thereby maximizing the output efficiency of the bus current in the gate lines disposed thereon.

[0034] In other words, this disclosure first designs different area ratios, i.e., widths, for the first extension 202 and the second extension 302. Based on this, if the widths of the first extension 202 and the second extension 302 are different, the width of the connection region 402 is greater than the smaller of the two widths and less than the sum of their widths; if the two widths are equal, the width of the connection region 402 is greater than the equal width and less than the sum of their widths. This makes the width of the connection region 402 different from the widths of the first extension 202 and the second extension 302 in the doped structure, taking into account both the carrier transport efficiency and passivation performance on the back surface side of the substrate layer 1. At the same time, the relatively increased width of the connection region 402 can also ensure the printing accuracy of the gate line paste on it. The increased gate line width reduces the line resistance, and the larger current flowing through it can be output efficiently, thereby improving the overall battery yield and power generation efficiency.

[0035] For example, when the outermost doped structure is a p-type doped structure, the conductivity type of the edge doped structure 4 is also p-type. In this case, if the width of the extension of the p-type doped structure is widened, and the width of the extension of the n-type doped structure is correspondingly narrowed to form both the p-type and n-type doped structures, that is, the width of the extension of the p-type doped structure is less than the width of the extension of the n-type doped structure, then the width of the p-type connection region 402 of the edge doped structure 4 can be simultaneously formed to be the same as the width of the extension of the larger p-type doped structure, or slightly narrowed so that its width is greater than the width of the extension of the n-type doped structure and slightly less than the width of the extension of the p-type doped structure. If the width of the extension of the n-type doped structure is widened, and the width of the extension of the p-type doped structure is correspondingly narrowed to form both the p-type and n-type doped structures, that is, the width of the extension of the n-type doped structure is greater than the width of the extension of the p-type doped structure, then the width of the p-type connection region 402 can be correspondingly widened so that the width of the p-type connection region 402 is greater than the width of the extension of the p-type doped structure and less than or equal to the width of the extension of the n-type doped structure. The same applies when the outermost doped structure is an n-type doped structure and the conductivity type of edge doped structure 4 is n-type, which will not be elaborated here.

[0036] In one embodiment, the ratio of the width W1 of the first extension 202 in the second direction to the width W2 of the second extension 302 in the second direction is in the range of 1:1 to 3:1.

[0037] In this disclosure, the sum of the widths of the first extension 202 and the second extension 302 is a constant value W. Under this premise, the ratio of the width of the p-type extension to the width of the n-type extension can be between 1:1 and 3:1, or the ratio of the width of the n-type extension to the width of the p-type extension can be between 1:1 and 3:1. That is, the width of the n-type extension can be greater than or equal to the width of the p-type extension within the above range, thereby optimizing the different battery structures to meet the requirements of both carrier transport performance and passivation performance, and providing more application possibilities for the component.

[0038] In one embodiment, the width W3 of the connection region 402 in the second direction ranges from (1 / 2W, W). That is, provided that the sum of the widths of the first extension 202 and the second extension 302 is a certain value W, the width W3 of the connection region 402 in the second direction is greater than half of the fixed value W and less than the fixed value W. Regardless of the conductivity type of the connection region 402, it is always ensured that the width of the connection region 402 is increased compared to the reference width, thereby improving the carrier transport performance when the connection region 402 connects the current collection region and the lead-out region 401. More importantly, the connection region 402 has sufficient width to further solve the printing accuracy problem of the grid line paste on it, reduce the line resistance of the grid line, improve the current output efficiency and the overall battery yield.

[0039] Furthermore, the width range of the connection region 402 is preferably (b, W), where b = max(W1, W2). That is, the width W3 of the connection region 402 in the second direction is greater than the width of the larger of the first extension 202 and the second extension 302, and less than the sum of the widths of the first extension 202 and the second extension 302. This strictly ensures that the width W3 of the connection region 402 in the second direction is greater than the width of all doped structures extending along the first direction under any circumstances, thereby further improving the output efficiency of the bus current in the gate line on the connection region 402.

[0040] In one embodiment, the width W3 of the connection region 402 in the second direction ranges from 100 to 800 μm, such as 100 μm, 200 μm, 300 μm, 350 μm, 400 μm, 500 μm, 650 μm, 700 μm, 800 μm, etc. If it is less than 100 μm, the difficulty of fabricating the gate line on the connection region 402 increases, and the line resistance of the gate line is relatively large, which is not conducive to high current transmission. If it is greater than 800 μm, it will compress the width of the extension adjacent to the connection region 402. Therefore, the above range facilitates the formation of the connection region 402 and the overall doped structure on the backlight surface, ensuring that the width setting of the connection region 402 matches the overall doped structure design. For example, if the width W3 of the connection region 402 in the second direction is set to 300 μm or 600 μm, the width distribution of each region of the battery doped structure has an optimal solution, and the formed gate line structure has excellent current transmission efficiency.

[0041] In one embodiment, such as Figure 1 and Figure 3 As shown, the aforementioned back-contact solar cell further includes: a corner doped structure 5, located in the first direction between the lead-out region 401 and the current-collecting portion closest to the edge of the substrate layer 1; the corner doped structure 5 includes a first portion 501 and a second portion 502, the first portion 501 extends along the first direction and is disposed adjacent to and spaced apart from the connection region 402, the second portion 502 extends along the second direction, and one end of the second portion 502 is connected to the end of the first portion 501 that is relatively close to the lead-out region 401, and the other end of the second portion 502 is connected to an extension portion with a conductivity type opposite to that of the connection region 402.

[0042] Compared Figure 5The conventional scheme shown, namely the third extension A adjacent to the connection region 402 in the second direction and with the opposite conductivity type, is connected to the outermost end of the fourth extension B located on the side of the third extension A away from the connection region 402 in the first direction; this disclosure further designs the "extension" located between the lead-out region 401 and the busbar to form a corner doped structure 5 including a first portion 501 and a second portion 502, wherein the first portion 501 is arranged parallel to the extension, and the second portion 502 connects the first portion 501 with another extension located on the side of the first portion 501 away from the connection region 402. However, in this disclosure, the connection between the second portion 502 and the other extension is moved inward compared to the conventional scheme, making it closer to the side of the lead-out region 401, such as... Figures 1 to 4 As shown, while keeping the area of ​​the doped region unchanged, the grid lines formed on it can have a shorter carrier transport and collection path, thereby improving the power generation efficiency of the battery.

[0043] In one embodiment, the ratio of the width W4 of the first portion 501 of the corner doped structure 5 in the second direction to the width W3 of the connecting region 402 in the second direction is in the range of 4:1 to 1:20.

[0044] That is, the width of the first portion 501, which extends in the same direction as the connection region 402, can be greater than or less than the width of the connection region 402. Based on the width design of the connection region 402 and the width of adjacent extensions with the same conductivity type as the connection region 402, the width of the first portion 501 is set within the aforementioned proportional range to ensure coordinated matching of the doped regions of the connection region 402 and its surrounding first portion 501 and other extensions, optimizing doping performance to improve passivation performance and carrier transport. For example, if the first portion 501 and the second extension 302 have the same conductivity type, and the connection region 402 has the opposite conductivity type to the first portion 501, then... Figure 1 As shown, the width W2 of the second extension 302 in the second direction is wider than the reference reference. In this case, the widths of both the first portion 501 and the connecting area 402 can be equal to the reference reference, meaning the ratio of the width W4 of the first portion 501 in the second direction to the width W3 of the connecting area 402 in the second direction is 1:1. Or as... Figure 3 As shown, the width W2 of the second extension 302 in the second direction is still wider than the reference reference, but the width W3 of the connecting area 402 in the second direction is also wider than the reference reference. The width W4 of the first part 501 in the second direction is narrowed relative to the reference reference. At this time, the ratio of the width W4 of the first part 501 in the second direction to the width W3 of the connecting area 402 in the second direction can be 1:3.

[0045] In one embodiment, the widths of the two first portions 501 located on either side of the connecting area 402 in the second direction may be different, and the sum of the width W4 of one of the first portions 501 in the second direction and the width W3 of the connecting area 402 in the second direction is a certain value W.

[0046] like Figure 1 and Figure 3 As shown, the sum of the width W4 of the first portion 501 in the second direction and the width W3 of the connection region 402 in the second direction is also a constant value W. Thus, while meeting the width requirement of the connection region 402, the width of the first portion 501 must also be adjusted accordingly to ensure the stability of the doped structure and the carrier transport performance in the edge region.

[0047] In one embodiment, such as Figure 2 and Figure 4 As shown, the aforementioned back-contact solar cell further includes: a first grid line 6, a second grid line 7, a connecting grid line 8, and a pad 9. The first grid line 6 is disposed on the first doped structure 2; the second grid line 7 is disposed on the second doped structure 3; the connecting grid line 8 is disposed on the connection region 402, and the width of the connecting grid line 8 is greater than the width of the first grid line 6 and the second grid line 7; the pad 9 is disposed on the lead-out region 401, and the connecting grid line 8 connects the pad 9 and the grid line at the outermost edge in the second direction.

[0048] For example, the first gate line 6, the second gate line 7, and the connecting gate line 8 can be formed by screen printing. The pad 9 is disposed on the lead-out area 401 and connected to the gate line located at the outermost edge in the first direction of the substrate layer 1. That is, if the outermost edge is the first gate line 6, the pad 9 is connected to the first gate line 6 through the connecting gate line 8, which is used to output the carriers of the first doped structure 2 and the edge doped structure 4 of the same conductivity type; if the outermost edge is the second gate line 7, the pad 9 is connected to the second gate line 7 through the connecting gate line 8, which is used to output the carriers of the second doped structure 3 and the edge doped structure 4 of the same conductivity type.

[0049] In one embodiment, of the first gate line 6 and the second gate line 7, one is a p-type gate line and the other is an n-type gate line, with the width of the p-type gate line being greater than the width of the n-type gate line.

[0050] Since the carrier transport and collection performance of p-type doped structures is generally weaker than that of n-type doped structures, this disclosure designs the width of the gate line on the p-type doped structure to be greater than that on the n-type doped structure in order to improve the transport and collection of hole carriers.

[0051] This disclosure also provides a back-contact solar cell module, including a plurality of the aforementioned back-contact solar cells, thus possessing all the advantages of the aforementioned back-contact solar cells, optimizing the performance of a single cell to achieve significant efficiency optimization at the module level, and ultimately expanding the application of the solar cell module in different scenarios.

[0052] Further functional descriptions of the above structures are the same as those of the corresponding embodiments described above, and will not be repeated here.

[0053] 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: A base layer (1) includes a light-receiving surface and a backlighting surface disposed opposite to each other; At least one set of first doped structures (2) and second doped structures (3) are formed at intervals on the backlight surface of the substrate layer (1) and have opposite conductivity types; the first doped structure (2) includes a first busbar (201) and a plurality of first extensions (202) connected together, and the second doped structure (3) includes a second busbar (301) and a plurality of second extensions (302) connected together, the first busbar (201) and the second busbar (301) are spaced apart along a first direction, and the first extensions (202) and the second extensions (302) are alternately spaced apart between the first busbar (201) and the second busbar (301) along a second direction; the width of the first extension (202) in the second direction is W1, the width of the second extension (302) in the second direction is W2, and the sum of the widths of the first extension (202) and the second extension (302) in the second direction is a certain value W; An edge-doped structure (4) is connected to the busbar closest to the edge of the substrate layer (1) in the first direction and has the same conductivity type as the busbar; the edge-doped structure (4) includes a lead-out region (401) and a connection region (402), the lead-out region (401) is adapted to provide pads (9), the connection region (402) connects the busbar and the lead-out region (401), the width of the connection region (402) in the second direction is W3, the range of W3 is (a, W), where when W1≠W2, a=min(W1, W2), and when W1=W2, a=W1=W2.

2. The back-contact solar cell according to claim 1, characterized in that, The ratio of the width W1 of the first extension (202) in the second direction to the width W2 of the second extension (302) in the second direction is in the range of 1:1 to 3:

1.

3. The back-contact solar cell according to claim 1, characterized in that, The width W3 of the connecting area (402) in the second direction ranges from (1 / 2W, W).

4. The back-contact solar cell according to claim 1, characterized in that, The width W3 of the connection area (402) in the second direction ranges from 100 to 800 μm.

5. The back-contact solar cell according to claim 1, characterized in that, Also includes: A corner doped structure (5) is located in the first direction between the lead-out region (401) and the busbar closest to the edge of the substrate layer (1); the corner doped structure (5) includes a first portion (501) and a second portion (502), the first portion (501) extends along the first direction and is disposed adjacent to the connection region (402) at intervals, the second portion (502) extends along the second direction, and one end of the second portion (502) is connected to one end of the first portion (501) that is relatively close to the lead-out region (401), and the other end of the second portion (502) is connected to an extension with a conductivity type opposite to that of the connection region (402).

6. The back-contact solar cell according to claim 5, characterized in that, The ratio of the width W4 of the first portion (501) of the corner doped structure (5) in the second direction to the width W3 of the connecting region (402) in the second direction is in the range of 4:1 to 1:

20.

7. The back-contact solar cell according to claim 5, characterized in that, The widths of the two first portions (501) located on both sides of the connecting area (402) in the second direction are different, and the sum of the width W4 of one of the first portions (501) in the second direction and the width W3 of the connecting area (402) in the second direction is a certain value W.

8. The back-contact solar cell according to claim 1, characterized in that, Also includes: The first gate line (6) is disposed on the first doped structure (2); The second gate line (7) is disposed on the second doped structure (3); A connecting grid line (8) is disposed on the connecting area (402), and the width of the connecting grid line (8) is greater than the width of the first grid line (6) and the second grid line (7); A pad (9) is disposed on the lead-out area (401), and the connecting gate line (8) connects the pad (9) and the gate line at the outermost edge in the first direction.

9. The back-contact solar cell according to claim 8, characterized in that, In the first gate line (6) and the second gate line (7), one of them is a p-type gate line and the other is an n-type gate line. The width of the p-type gate line is greater than the width of the n-type gate line.

10. A back-contact solar cell module, characterized in that, include: The back-contact solar cell according to any one of claims 1-9.

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