Solar cell, cell assembly and photovoltaic system

Abstract

The invention discloses a solar cell, a cell module and a photovoltaic system. The solar cell comprises a silicon substrate, a plurality of first doped regions and a plurality of second doped regions, wherein the first doped regions and the second doped regions are arranged on the first side of the silicon substrate; the first doped region and the second doped region are sequentially arranged along the first direction and are arranged at an interval; an isolation groove is arranged between the adjacent first doped region and second doped region, and the isolation groove is used for isolating the first doped region and the second doped region; the isolation grooves comprise first isolation grooves and second isolation grooves, and the first isolation grooves and the second isolation grooves are sequentially arranged at intervals in the first direction; the width of the first isolation groove along the first direction is smaller than that of the second isolation groove along the first direction, and the vertical projection of at least one of two opposite side walls of the second isolation groove along the first direction on the silicon substrate comprises a first concave-convex structure. The risk of hidden crack of the cell can be reduced, the reliability of the cell is improved, and the photoelectric conversion efficiency of the cell is improved.

Description

[0001] This patent application claims priority to Chinese application No. 2025204783644, filed on March 18, 2025, entitled "Solar Cells, Cell Modules and Photovoltaic Systems", the entire contents of which are incorporated herein by reference. Technical Field

[0002] This invention relates to the field of solar cell technology, and more particularly to a solar cell, a battery module, and a photovoltaic system. Background Technology

[0003] Back-contact solar cells are cells in which both the emitter and base contact electrodes are placed on the back (non-light-receiving surface) of the cell. The light-receiving surface of the cell is not blocked by any metal electrodes, which effectively increases the short-circuit current of the cell.

[0004] In related technologies, to prevent leakage current between the P-region and N-region of a back-contact solar cell, trenches are typically used for isolation. However, after the trenches are fabricated in these technologies, the cell is at risk of microcracks, affecting its reliability. Summary of the Invention

[0005] This invention provides a solar cell, a battery module, and a photovoltaic system to reduce the risk of microcracks in the battery, improve battery reliability, and increase the photoelectric conversion efficiency of the battery.

[0006] According to one aspect of the present invention, a solar cell is provided, comprising:

[0007] A silicon substrate, and a plurality of first doped regions and a plurality of second doped regions disposed on a first side of the silicon substrate; the first doped regions and the second doped regions are arranged sequentially along a first direction and are spaced apart from each other;

[0008] An isolation trench is provided between adjacent first and second doped regions, the isolation trench being used to isolate the first doped region and the second doped region; the isolation trench includes a first isolation trench and a second isolation trench, which are arranged alternately along the first direction.

[0009] The width of the first isolation groove along the first direction is smaller than the width of the second isolation groove along the first direction;

[0010] At least one of the two sidewalls of the second isolation trench opposite each other along the first direction includes a first convex-concave structure in its vertical projection onto the silicon substrate.

[0011] Optionally, the first convex-concave structure includes at least one of wavy lines and zigzag lines.

[0012] Optionally, the first concave-convex structure is periodic.

[0013] Optionally, the undulation of the sidewall of the first isolation trench projected vertically onto the silicon substrate along the first direction is less than the undulation of the sidewall of the second isolation trench projected vertically onto the silicon substrate along the first direction.

[0014] Optionally, the degree of undulation of at least one of the two sidewalls of the first isolation trench that are opposite each other along the first direction when projected vertically onto the silicon substrate includes a second concave-convex structure.

[0015] The degree of undulation in the second concave-convex structure is less than that in the first concave-convex structure.

[0016] Optionally, the vertical projection of the sidewalls of the first isolation trench opposite each other along the first direction onto the silicon substrate is a straight line.

[0017] Optionally, a portion of the first doped region is adjacent to the second doped region along the second direction, and the isolation trench further includes a third isolation trench, which is disposed between the first doped region and the second doped region along the second direction, and is connected to the first isolation trench and the second isolation trench; wherein, the second direction and the first direction intersect each other;

[0018] The width of the third isolation groove along the second direction is greater than the width of the first isolation groove along the first direction; the width of the third isolation groove along the second direction is less than the width of the second isolation groove along the first direction.

[0019] Optionally, the width of the third isolation groove along the second direction is a fixed value, or the width of the third isolation groove along the second direction gradually decreases along the direction from the second isolation groove to the first isolation groove.

[0020] Optionally, the width of the first isolation groove along the first direction is greater than or equal to 40 micrometers and less than or equal to 70 micrometers;

[0021] The width of the second isolation groove along the first direction is greater than or equal to 60 micrometers and less than or less than 100 micrometers.

[0022] Optionally, the absolute value of the difference between the widths of the different first isolation grooves along the first direction is less than or equal to a first set value;

[0023] The absolute value of the difference in width of the different second isolation grooves along the first direction is less than or equal to the second set value.

[0024] Optionally, the first set value is less than or equal to 5 micrometers;

[0025] The second setting value is less than or equal to 5 micrometers.

[0026] Optionally, the longitudinal section of the isolation trench is trapezoidal, wherein the longitudinal section is perpendicular to the surface of the silicon substrate adjacent to the first doped region and parallel to the first direction, and the lower base of the trapezoid is located on the side of the upper base of the trapezoid away from the silicon substrate.

[0027] Optionally, the first surface of the silicon substrate has a plurality of first regions and a plurality of second regions, the first regions and the second regions being arranged sequentially at intervals along the first direction, and a trench being formed between adjacent first regions and second regions; the first doped region is disposed in the first region, and the second doped region is disposed in the second region;

[0028] The silicon substrate is further provided with a first passivation layer and a first antireflection layer on its first side; the first passivation layer is disposed on the side of the first doped region and the second doped region away from the silicon substrate, and the first antireflection layer is disposed on the side of the first passivation layer away from the silicon substrate; the first passivation layer and the first antireflection layer cover the first doped region, the second doped region and the trench.

[0029] The region between the first antireflection layer on the adjacent surfaces of the first doped region and the second doped region is the isolation trench.

[0030] Optionally, the solar cell also includes:

[0031] Second passivation layer, second antireflection layer, first electrode and second electrode;

[0032] The second passivation layer and the second antireflection layer are disposed on the second side of the silicon substrate, the first side and the second side are disposed opposite to each other, and the second antireflection layer is disposed on the side of the second passivation layer away from the silicon substrate;

[0033] The first electrode is disposed on the side of the first antireflection layer away from the silicon substrate, and the first electrode passes through the first antireflection layer and the first passivation layer to contact the first doped region; the second electrode is disposed on the side of the first antireflection layer away from the silicon substrate, and the second electrode passes through the first antireflection layer and the first passivation layer to contact the second doped region.

[0034] Optionally, one of the first doped region and the second doped region is a P-type doped region and the other is an N-type doped region, and the silicon substrate is an N-type silicon substrate or a P-type silicon substrate.

[0035] According to another aspect of the present invention, a battery assembly is provided, including the solar cell described in any embodiment of the present invention.

[0036] According to another aspect of the present invention, a photovoltaic system is provided, including the battery module described in any embodiment of the present invention.

[0037] This invention, through the provision of an isolation trench including a first isolation trench and a second isolation trench, is arranged sequentially and alternately along a first direction. The width of the first isolation trench along the first direction is smaller than the width of the second isolation trench along the first direction X. That is, the isolation trenches are arranged with alternating widths along the first direction. The narrower first isolation trench requires less laser light than the second isolation trench, thereby reducing overall damage caused by laser processing. Simultaneously, the alternating width arrangement of the isolation trenches can alleviate stress caused by the same laser intensity, reducing the probability of microcracks in the solar cell and increasing cell reliability. Furthermore, by providing a first concave-convex structure in the vertical projection of at least one of the two opposing sidewalls of the second isolation trench onto the silicon substrate along the first direction, the surface area of ​​the sidewalls of the second isolation trench is increased, thereby increasing the area of ​​the passivation layer on the surface of the second isolation trench. This can reduce carrier recombination rate and improve the photoelectric conversion efficiency of the solar cell.

[0038] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of the present invention, nor is it intended to limit the scope of the invention. Other features of the invention will become readily apparent from the following description. Attached Figure Description

[0039] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0040] Figure 1 This is a schematic diagram of the structure of a solar cell provided in an embodiment of the present invention;

[0041] Figure 2 This is a schematic diagram of another solar cell structure provided in an embodiment of the present invention;

[0042] Figure 3 This is a top view of the solar cell provided in an embodiment of the present invention. Detailed Implementation

[0043] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0044] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0045] As mentioned in the background section, in related technologies, the fabrication of isolation grooves carries the risk of microcracks in the battery, affecting battery reliability. The inventors discovered through research that the reason for this problem lies in the fact that in related technologies, the isolation grooves are formed through laser processing. The wider the isolation groove, the more laser light is required, and the higher the risk of microcracks in the battery cell during laser processing. Therefore, excessive laser light increases internal stress in the cell, drastically increasing the risk of microcracks and reducing battery cell reliability.

[0046] Based on this, this embodiment provides a solar cell. Figure 1 This is a schematic diagram of the structure of a solar cell provided in an embodiment of the present invention. Figure 2 This is a schematic diagram of another solar cell structure provided in an embodiment of the present invention. Figure 3 This is a top view of the solar cell provided in an embodiment of the present invention. (Reference) Figures 1-3 The solar cells include:

[0047] A silicon substrate 10, and a plurality of first doped regions 20 and a plurality of second doped regions 30 disposed on a first side of the silicon substrate 10; the first doped regions 20 and the second doped regions 30 are arranged sequentially along a first direction X and are spaced apart from each other;

[0048] An isolation trench 40 is provided between adjacent first doped region 20 and second doped region 30. The isolation trench 40 is used to isolate the first doped region 20 and the second doped region 30. The isolation trench 40 includes a first isolation trench 41 and a second isolation trench 42. Along the first direction X, the first isolation trench 41 and the second isolation trench 42 are arranged at intervals.

[0049] The width D1 of the first isolation groove 41 along the first direction X is smaller than the width D2 of the second isolation groove 42 along the first direction X.

[0050] At least one of the two sidewalls of the second isolation trench 42 opposite each other along the first direction X includes a first convex-concave structure 421 in the vertical projection of the second isolation trench 42 onto the silicon substrate 10.

[0051] The silicon substrate 10 has a front side and a back side. The front side is the side of the solar cell that receives light when it is working, and the back side is the side that is backlit when the solar cell is working. The first side of the silicon substrate 10 is the backlit side. The silicon substrate 10 can be a monocrystalline silicon wafer or a polycrystalline silicon wafer, and it can be a P-type silicon wafer or an N-type silicon wafer; no specific limitation is made here. The first doped region 20 and the second doped region 30 can be a P-type doped region and an N-type doped region, respectively. The isolation trench 40 is used to isolate adjacent first doped regions 20 and second doped regions 30 to prevent leakage current conduction between the first doped region 20 and the third doped region 30. The first isolation trench 41 and the second isolation trench 42 have the same shape. The width D1 of the first isolation trench 41 and the width D2 of the second isolation trench 42 are the widths of the first isolation trench 41 and the second isolation trench 42 at the same position. For example, refer to Figure 2 The longitudinal section of the first isolation groove 41 and the second isolation groove 42 is trapezoidal. The width of the first isolation groove 41 and the second isolation groove 42 can both be the width of the upper base of the trapezoid, or both be the width of the lower base of the trapezoid, or the width between the two waists at the center of the trapezoid, or the average width. One of the two sidewalls of the second isolation groove 42 opposite each other along the first direction X can have a first concave-convex structure 421 in its vertical projection onto the silicon substrate 10, or both sidewalls opposite each other along the first direction X can have the first concave-convex structure 421 in their vertical projection onto the silicon substrate 10.

[0052] Specifically, the isolation groove 40 can be prepared by laser processing and texturing. The wider the isolation groove 40, the more laser light is required, and the more prone the battery is to microcracks. In this embodiment, the isolation groove 40 includes a first isolation groove 41 and a second isolation groove 42. Along the first direction X, the first isolation groove 41 and the second isolation groove 42 are arranged alternately. The width D1 of the first isolation groove 41 along the first direction X is smaller than the width D2 of the second isolation groove 42 along the first direction X. That is, along the first direction X, the isolation grooves 40 are arranged with alternating widths. The narrower first isolation groove 41 requires less laser light than the second isolation groove 42, thereby reducing the overall damage caused by laser processing. At the same time, the alternating width of the isolation grooves 40 can alleviate the stress caused by the same laser intensity, reduce the probability of microcracks in the battery cell, and increase the reliability of the battery. Furthermore, by setting at least one of the two sidewalls of the second isolation trench 42 opposite to each other along the first direction X to include a first concave-convex structure 421 in the vertical projection of the second isolation trench 42 onto the silicon substrate 10, the surface area of ​​the sidewall of the second isolation trench 42 is increased, and the area of ​​the passivation layer disposed on the surface of the second isolation trench 42 is increased, which can reduce the carrier recombination rate and improve the photoelectric conversion efficiency of the solar cell.

[0053] Based on the above embodiments, optionally, the first concave-convex structure 421 includes at least one of wavy lines and zigzag lines.

[0054] Specifically, in the vertical projection of the same sidewall of the second isolation trench 42 onto the silicon substrate 10, the first concave-convex structure 421 can all be wavy lines; or all be wavy lines; or it can be partially wavy and partially wavy lines. By including at least one of wavy lines and wavy lines in the first concave-convex structure 421, the area of ​​the sidewall of the second isolation trench 42 can be further increased, the area of ​​the passivation layer can be further increased, the carrier recombination rate can be further reduced, and the photoelectric conversion efficiency of the solar cell can be further improved.

[0055] Based on the above embodiments, optionally, the first concave-convex structure 421 is periodic. This can further increase the area of ​​the sidewall of the second isolation trench 42, further increase the area of ​​the passivation layer, further reduce the carrier recombination rate, and further improve the photoelectric conversion efficiency of the solar cell.

[0056] Based on the above embodiments, optionally, the undulation of the vertical projection of the opposite sidewall of the first isolation trench 41 along the first direction X onto the silicon substrate 10 is less than the undulation of the vertical projection of the opposite sidewall of the second isolation trench 42 along the first direction onto the silicon substrate 10.

[0057] Specifically, the sidewall of the first isolation trench 41 may not include any uneven structure, or may include an uneven structure with a small degree of undulation. Two parallel straight lines are provided on both sides of the sidewall of the first isolation trench 41 in the vertical projection onto the silicon substrate 10, each line contacting the vertical projection. The maximum distance between the two lines represents the degree of undulation of the sidewall of the first isolation trench 41 in the vertical projection onto the silicon substrate 10. Similarly, two parallel straight lines are provided on both sides of the opposite sidewall of the second isolation trench 42 in the first direction in the vertical projection onto the silicon substrate 10, each line contacting the vertical projection. The maximum distance between the two lines represents the degree of undulation of the sidewall of the second isolation trench 42 in the vertical projection onto the silicon substrate 10. For example, the degree of undulation of the sidewall of the first isolation trench 41 in the vertical projection onto the silicon substrate 10 can be represented by straightness, and the degree of undulation of the second isolation trench 42 in the vertical projection onto the silicon substrate 10 can also be represented by straightness.

[0058] If the sidewall of the first isolation trench 41 has the same uneven structure as the sidewall of the second isolation trench 42, the first isolation trench 41 would require a larger width, increasing the amount of laser used and the risk of microcracks in the battery. By making the undulation of the vertical projection of the opposite sidewall of the first isolation trench 41 along the first direction X onto the silicon substrate 10 less than the undulation of the vertical projection of the opposite sidewall of the second isolation trench 42 along the first direction onto the silicon substrate 10, the first isolation trench 41 can be made with a smaller width. At the same time, the sidewall of the second isolation trench 42 is provided with the first uneven structure 421. This ensures that damage caused by laser processing is reduced, stress caused by the same laser intensity is alleviated, the probability of microcracks in the battery cell is reduced, and the reliability of the battery is increased. At the same time, it can reduce the carrier loading rate and improve the photoelectric conversion efficiency.

[0059] Based on the above embodiments, optionally, at least one of the two sidewalls of the first isolation groove 41 that are opposite each other along the first direction X includes a second concave-convex structure 411 in the vertical projection of the silicon substrate 10.

[0060] The degree of undulation of the second concave-convex structure 411 is less than that of the first concave-convex structure 421.

[0061] Specifically, the first distance between the highest point of the convex portion and the lowest point of the concave portion of the second concave-convex structure 411 represents the degree of undulation of the second concave-convex structure 411. The second distance between the highest point of the convex portion and the lowest point of the concave portion of the first concave-convex structure 421 represents the degree of undulation of the first concave-convex structure 421. The degree of undulation of the second concave-convex structure 411 is less than that of the first concave-convex structure 421, that is, the first distance is less than the second distance. The greater the degree of undulation of the concave-convex structure, the more concave the concave portion and / or more convex the convex portion of the structure.

[0062] By setting the degree of undulation of the second concave-convex structure 411 to be less than that of the first concave-convex structure 421, the first isolation groove 41 can be set to a smaller width. This ensures that damage caused by laser processing is reduced, stress caused by the same laser intensity is alleviated, the probability of microcracks in the cell is reduced, and the reliability of the cell is increased. At the same time, it can further reduce the carrier loading rate and improve the photoelectric conversion efficiency.

[0063] Based on the above embodiments, optionally, the vertical projection of the sidewalls of the first isolation trench 41 opposite to each other along the first direction X onto the silicon substrate 10 is a straight line.

[0064] This design can further reduce the width of the first isolation groove 41, reduce the amount of laser used in the fabrication of the first isolation groove 41, reduce the probability of microcracks in the battery, and reduce the difficulty of the fabrication process of the first isolation groove 41.

[0065] It should be noted that in this embodiment, the vertical projection of the sidewall of the first isolation groove 41 opposite to the first direction X onto the silicon substrate 10 is a straight line, which means that the straightness of the vertical projection of the sidewall of the first isolation groove 41 opposite to the first direction X onto the silicon substrate 10 is less than or equal to a set value. This set value can be a value greater than or equal to 0. For example, the set value can be 0 or a value close to 0.

[0066] Based on the above embodiments, optionally, a portion of the first doped region 20 is adjacent to the second doped region 30 along the second direction Y, and the isolation trench 40 further includes a third isolation trench 43, which is disposed between the first doped region 20 and the second doped region 30 along the second direction Y, and the third isolation trench 43 is connected to the first isolation trench 41 and the second isolation trench 42; wherein, the second direction X and the first direction Y intersect each other;

[0067] The width D3 of the third isolation groove 43 along the second direction Y is greater than the width D1 of the first isolation groove 41 along the first direction X; the width D3 of the third isolation groove 43 along the second direction Y is less than the width D2 of the second isolation groove 42 along the first direction X.

[0068] Specifically, the third isolation trench 43 is used to isolate the first doped region 20 and the second doped region 30. The longitudinal section of the third isolation trench 43 along the width direction has the same shape as the longitudinal section of the first isolation trench 41 and the second isolation trench 42 along the width direction. The width D3 of the third isolation trench 43, the width D1 of the first isolation trench 41, and the width D2 of the second isolation trench 42 are the widths of the first isolation trench 41, the second isolation trench 42, and the third isolation trench 43 at the same position. For example, refer to... Figure 2The longitudinal sections of the first isolation groove 41, the second isolation groove 42 and the third isolation groove 43 are trapezoidal. The widths of the first isolation groove 41, the second isolation groove 42 and the third isolation groove 43 can all be the width of the upper base of the trapezoid, or all be the width of the lower base of the trapezoid, or the width between the two sides of the trapezoid at the center, or the average width.

[0069] By setting the width D3 of the third isolation groove 43 to be between the width D1 of the first isolation groove 41 and the width D2 of the second isolation groove 42, the width of the entire isolation groove 40 gradually changes from large to small, which can avoid stress concentration and further reduce the risk of microcracks in the solar cell.

[0070] Based on the above embodiments, optionally, the width D3 of the third isolation groove 43 along the second direction Y is a fixed value, or the width D3 of the third isolation groove 43 along the second direction Y gradually decreases along the direction from the second isolation groove 42 to the first isolation groove 41.

[0071] Specifically, the width D3 of the third isolation groove 43 along the second direction Y is a fixed value, that is, the width of the third isolation groove 43 at each position along the first direction X is the same, and all are the same value. This setting ensures that the width of the isolation groove 40 gradually decreases, avoids stress concentration, and reduces the difficulty of the process.

[0072] Along the direction from the second isolation groove 42 to the first isolation groove 41, the width D3 of the third isolation groove 43 gradually decreases along the second direction Y. That is, the closer the third isolation groove 43 is to the second isolation groove 42, the larger its width becomes. This allows the isolation groove 40 to gradually decrease in width from the second isolation groove 42 (which is wider) to the first isolation groove 41 (which is narrower), further avoiding stress concentration and preventing the occurrence of microcracks.

[0073] Based on the above embodiments, optionally, refer to the following: Figures 1-3 The width D1 of the first isolation groove 41 along the first direction X is greater than or equal to 40 micrometers and less than or equal to 70 micrometers;

[0074] The width of the second isolation groove 42 along the first direction X is greater than or equal to 60 micrometers and less than or less than 100 micrometers.

[0075] Specifically, the wider the isolation trench 40, the more laser light is required, and the greater the risk of microcracks in the solar cell. If the isolation trench 40 is too narrow, it may not effectively isolate the first doped region 20 and the second doped region 30. By setting the width D1 of the first isolation trench 41 along the first direction X to be greater than or equal to 40 micrometers and less than or equal to 70 micrometers, and the width of the second isolation trench 42 along the first direction X to be greater than or equal to 60 micrometers and less than or less than 100 micrometers, it can be ensured that both the first isolation trench 41 and the second isolation trench 42 can effectively isolate the first doped region 20 and the second doped region 30. At the same time, it can avoid excessive laser light usage in the first isolation trench 41 and the second isolation trench 42, reducing damage caused by laser processing. Furthermore, by using the above-mentioned width range for the first isolation trench 41 and the second isolation trench 42, the overall stress of the solar cell can be better adjusted, stress concentration can be reduced, the probability of microcracks in the solar cell can be reduced, and the reliability of the solar cell can be increased.

[0076] For example, the width D1 of the first isolation groove 41 can be 45 micrometers, 50 micrometers, 55 micrometers, 56.6 micrometers, 58.1 micrometers, 60 micrometers, or 65 micrometers, etc. The width D1 of the second isolation groove 42 can be 65 micrometers, 70 micrometers, 75 micrometers, 80 micrometers, 85 micrometers, 85.4 micrometers, 88.8 micrometers, or 90 micrometers, etc.

[0077] Based on the above embodiments, optionally, the absolute value of the difference between the widths D1 of different first isolation grooves along the first direction X of 41 is less than or equal to a first set value.

[0078] The absolute value of the difference in width D2 of different second isolation grooves 42 along the first direction X is less than or equal to the second set value.

[0079] Specifically, the width D1 of all the first isolation grooves 41 along the first direction X can be the same or different, and the width D2 of all the second isolation grooves 42 along the first direction X can be the same or different. When the width D1 of all the first isolation grooves 41 along the first direction X is the same, the first setting value is 0. When the width D2 of all the second isolation grooves 41 along the first direction X is the same, the second setting value is 0.

[0080] The first and second set values ​​can be determined based on the allowable process error. When the absolute value of the difference in width D1 along the first direction X of different first isolation grooves 41 is less than or equal to the first set value, the width D1 of all first isolation grooves 41 along the first direction X is basically the same. Similarly, when the absolute value of the difference in width D2 along the first direction X of different second isolation grooves 42 is less than or equal to the second set value, the width D2 of all second isolation grooves 42 along the first direction X is basically the same. This setting ensures uniform stress distribution throughout the solar cell, preventing stress concentration that could lead to microcracks.

[0081] Based on the above embodiments, optionally, the first set value is less than or equal to 5 micrometers, and the second set value is less than or equal to 5 micrometers. This setting ensures that the dimensions of the first isolation groove 41 and the second isolation groove 42 are sufficient to reduce stress and prevent stress concentration from causing microcracks, while reducing the difficulty of the manufacturing process.

[0082] For example, the first setting value can be 2 micrometers, 3 micrometers or 4 micrometers, etc., and the second setting value can be 2 micrometers, 3 micrometers or 4 micrometers, etc.

[0083] Based on the above embodiments, optionally, the longitudinal section of the isolation trench 40 is trapezoidal, wherein the longitudinal section is perpendicular to the surface of the silicon substrate 10 adjacent to the first doped region 20 and parallel to the first direction X, and the lower base of the trapezoid is located on the side of the upper base of the trapezoid away from the silicon substrate 10.

[0084] Specifically, Figure 1 The diagram shows the longitudinal section of the isolation region 40. The lower base of the trapezoid is located on the side of the upper base of the trapezoid adjacent to the silicon substrate 10. That is, the width of the isolation trench 40 is smaller on the side adjacent to the silicon substrate 10 and larger on the side away from the silicon substrate 10. In other words, the closer to the silicon substrate 10, the smaller the width of the isolation trench 40. This arrangement can further reduce the internal stress of the battery, further avoid microcracks, and improve battery reliability.

[0085] Based on the above embodiments, optionally, the first surface of the silicon substrate 10 has a plurality of first regions 11 and a plurality of second regions 12, the first regions 11 and the second regions 12 are arranged sequentially at intervals along the first direction X, and a trench 13 is provided between adjacent first regions 11 and second regions 12; a first doped region 20 is disposed in the first region 11, and a second doped region 30 is disposed in the second region 12.

[0086] A first passivation layer 50 and a first antireflection layer 60 are also provided on the first side of the silicon substrate 10; the first passivation layer 50 is provided on the side of the first doped region 20 and the second doped region 30 away from the silicon substrate 10, and the first antireflection layer 60 is provided on the side of the first passivation layer 50 away from the silicon substrate 10. The first passivation layer 50 and the first antireflection layer 60 cover the first doped region 20, the second doped region 30 and the trench 13.

[0087] The region between the first antireflection layer 60 on the adjacent surfaces of the first doped region 20 and the second doped region 30 is an isolation trench 40.

[0088] For details, please refer to [link / reference]. Figure 1The first passivation layer 50 covers the first doped region 20, the second doped region 30, and the trench 13, meaning the first passivation layer 50 covers the entire back side of the silicon substrate 10. The first passivation layer 50 can be a passivating film layer such as an aluminum oxide layer, and there are no specific limitations here. The first antireflection layer 60 is used to reduce sunlight reflection, allowing more sunlight to be absorbed inside the solar cell. The first antireflection layer 60 can be a film layer such as a silicon nitride layer.

[0089] Based on the above embodiments, optionally, refer to the following: Figure 2 The solar cell also includes: a second passivation layer 70, a second antireflection layer 80, a first electrode 90, and a second electrode 100;

[0090] The second passivation layer 70 and the second antireflection layer 80 are disposed on the second side of the silicon substrate 10, with the first side and the second side disposed opposite to each other, and the second antireflection layer 80 is disposed on the side of the second passivation layer 70 away from the silicon substrate 10.

[0091] The first electrode 90 is disposed on the side of the first antireflection layer 60 away from the silicon substrate 10, and the first electrode 90 passes through the first antireflection layer 60 and the first passivation layer 50 to contact the first doped region 20; the second electrode 100 is disposed on the side of the first antireflection layer 60 away from the silicon substrate 10, and the second electrode 100 passes through the first antireflection layer 60 and the first passivation layer 50 to contact the second doped region 30.

[0092] For details, please refer to Figure 2 The front side of the silicon substrate 10 is covered by a second passivation layer 70 and a second antireflection layer 80. The second passivation layer 70 can be a passivating film such as an aluminum oxide layer. The second antireflection layer 80 is used to reduce sunlight reflection, allowing more sunlight to be absorbed inside the solar cell. The second antireflection layer 80 can be a silicon nitride layer or a similar film. Both the first electrode 90 and the second electrode 100 can be metal electrodes.

[0093] Based on the above embodiments, optionally, one of the first doped region 20 and the second doped region 30 is a P-type doped region and the other is an N-type doped region, and the silicon substrate 10 is an N-type silicon substrate or a P-type silicon substrate.

[0094] Specifically, the first doped region 20 and the second doped region 30 can be polycrystalline silicon doped regions, and the silicon substrate 10 can be a monocrystalline silicon substrate.

[0095] This invention also provides a battery assembly, including the solar cell described in any embodiment of this invention.

[0096] This invention also provides a photovoltaic system, including the battery module described in any embodiment of this invention.

[0097] It should be understood that the various forms of processes shown above can be used, with steps reordered, added, or deleted. For example, the steps described in this invention can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution of this invention can be achieved, and this is not limited herein.

[0098] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A solar cell, characterized in that, include: A silicon substrate, and a plurality of first doped regions and a plurality of second doped regions disposed on a first side of the silicon substrate; the first doped regions and the second doped regions are arranged sequentially along a first direction and are spaced apart from each other; An isolation trench is provided between adjacent first and second doped regions, the isolation trench being used to isolate the first doped region and the second doped region; the isolation trench includes a first isolation trench and a second isolation trench, which are arranged alternately along the first direction. The width of the first isolation groove along the first direction is smaller than the width of the second isolation groove along the first direction; At least one of the two sidewalls of the second isolation trench opposite each other along the first direction includes a first convex-concave structure in its vertical projection onto the silicon substrate.

2. The solar cell according to claim 1, characterized in that: The first concave-convex structure includes at least one of wavy lines and zigzag lines.

3. The solar cell according to claim 1, characterized in that: The first concave-convex structure is periodic.

4. The solar cell according to claim 1, characterized in that: The degree of undulation of the sidewall of the first isolation trench projected vertically onto the silicon substrate along the first direction is less than the degree of undulation of the sidewall of the second isolation trench projected vertically onto the silicon substrate along the first direction.

5. The solar cell according to claim 4, characterized in that: At least one of the two sidewalls of the first isolation trench opposite each other along the first direction includes a second concave-convex structure in its vertical projection onto the silicon substrate; The degree of undulation in the second concave-convex structure is less than that in the first concave-convex structure.

6. The solar cell according to claim 4, characterized in that: The vertical projection of the sidewalls of the first isolation trench opposite each other along the first direction onto the silicon substrate is a straight line.

7. The solar cell according to claim 1, characterized in that: A portion of the first doped region is adjacent to the second doped region along the second direction. The isolation trench further includes a third isolation trench, which is disposed between the first doped region and the second doped region along the second direction and is connected to the first isolation trench and the second isolation trench. The second direction and the first direction intersect each other. The width of the third isolation groove along the second direction is greater than the width of the first isolation groove along the first direction; the width of the third isolation groove along the second direction is less than the width of the second isolation groove along the first direction.

8. The solar cell according to claim 7, characterized in that: The width of the third isolation groove along the second direction is a fixed value, or the width of the third isolation groove gradually decreases along the second direction from the second isolation groove to the first isolation groove.

9. The solar cell according to claim 1, characterized in that: The width of the first isolation groove along the first direction is greater than or equal to 40 micrometers and less than or equal to 70 micrometers; The width of the second isolation groove along the first direction is greater than or equal to 60 micrometers and less than or less than 100 micrometers.

10. The solar cell according to claim 1, characterized in that: The absolute value of the difference in the width of the different first isolation grooves along the first direction is less than or equal to a first set value; The absolute value of the difference in width of the different second isolation grooves along the first direction is less than or equal to the second set value.

11. The solar cell according to claim 10, characterized in that: The first set value is less than or equal to 5 micrometers; The second setting value is less than or equal to 5 micrometers.

12. The solar cell according to claim 1, characterized in that: The longitudinal section of the isolation trench is trapezoidal, wherein the longitudinal section is perpendicular to the surface of the silicon substrate adjacent to the first doped region and parallel to the first direction, and the lower base of the trapezoid is located on the side of the upper base of the trapezoid away from the silicon substrate.

13. The solar cell according to claim 1, characterized in that: The first surface of the silicon substrate has a plurality of first regions and a plurality of second regions, the first regions and the second regions being arranged sequentially at intervals along the first direction, and a trench being formed between adjacent first regions and second regions; the first doped region is disposed in the first region, and the second doped region is disposed in the second region; The silicon substrate is further provided with a first passivation layer and a first antireflection layer on its first side; the first passivation layer is disposed on the side of the first doped region and the second doped region away from the silicon substrate, and the first antireflection layer is disposed on the side of the first passivation layer away from the silicon substrate; the first passivation layer and the first antireflection layer cover the first doped region, the second doped region and the trench. The region between the first antireflection layer on the adjacent surfaces of the first doped region and the second doped region is the isolation trench.

14. The solar cell according to claim 13, characterized in that, Also includes: Second passivation layer, second antireflection layer, first electrode and second electrode; The second passivation layer and the second antireflection layer are disposed on the second side of the silicon substrate, the first side and the second side are disposed opposite to each other, and the second antireflection layer is disposed on the side of the second passivation layer away from the silicon substrate; The first electrode is disposed on the side of the first antireflection layer away from the silicon substrate, and the first electrode passes through the first antireflection layer and the first passivation layer to contact the first doped region; The second electrode is disposed on the side of the first antireflection layer away from the silicon substrate, and the second electrode passes through the first antireflection layer and the first passivation layer to contact the second doped region.

15. The solar cell according to claim 1, characterized in that, One of the first doped region and the second doped region is a P-type doped region and the other is an N-type doped region, and the silicon substrate is an N-type silicon substrate or a P-type silicon substrate.

16. A battery assembly, characterized in that, The solar cell includes any one of claims 1-15.

17. A photovoltaic system, characterized in that, Includes the battery assembly as described in claim 16.

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