Solar cell and photovoltaic module

Abstract

The invention discloses a solar cell and a photovoltaic module. The solar cell comprises a semiconductor substrate and current collection grid lines, and the surface, provided with the current collection grid lines, of the semiconductor substrate is a target surface; the target surface is provided with an edge area and a middle area along the extension direction of the collector grid lines, and the extension direction of the collector grid lines is a first direction; the edge area is provided with a plurality of first texture structures extending in the second direction, and the middle area is provided with a plurality of second texture structures extending in the second direction; in the extension direction of the collector grid lines, the first texture structures located in the edge area have first distribution density, the second texture structures located in the middle area have second distribution density, the first distribution density is larger than the second distribution density, and the first direction intersects with the second direction. The collecting grid lines are not approximately parallel to the texture structures, and the distribution density of the first texture structures in the edge region is higher than that of the second texture structures in the middle region, so that the linearity of the collecting grid lines is improved.

Description

Technical Field

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

[0002] Solar cells convert sunlight into electricity. Traditionally, the collector grid lines of solar cells extend parallel to the textured structure on the solar cell surface, resulting in poor collector grid linearity. This increases the series resistance of the solar cell and reduces efficiency. Furthermore, poorly linear collector grid lines may cover more of the solar cell surface, reducing the effective light-receiving area and leading to lower cell efficiency. Summary of the Invention

[0003] The object of the present invention is to provide a solar cell and a photovoltaic module to improve the linearity of the collector grid, reduce the series resistance, increase the light receiving area, and improve the cell efficiency.

[0004] In a first aspect, the present invention provides a solar cell comprising a semiconductor substrate and a collector grid line, wherein the surface of the semiconductor substrate provided with the collector grid line is a target surface; Along the extension direction of the collector grid line, the target surface has an edge region and a middle region, and the middle region is located between the two edge regions; the extension direction of the collector grid line is a first direction; The edge region has a plurality of first texture structures extending along the second direction, and the middle region has a plurality of second texture structures extending along the second direction; Along the extension direction of the collector grid line, the first texture structure located in the edge area has a first distribution density, and the second texture structure located in the middle area has a second distribution density, and the first distribution density is greater than the second distribution density; the first direction intersects the second direction.

[0005] When using the above technical solution, the surface of the semiconductor substrate provided with the collector grid line, i.e., the target surface, has edge regions located on either side and a middle region located between the two edge regions in the direction in which the collector grid line extends. The extension direction (second direction) of the first texture structure in the edge region and the second texture structure in the middle region both intersect with the extension direction (first direction) of the collector grid line and are not approximately parallel. Compared to existing structures in which the extension direction of the collector grid line is approximately parallel to the extension direction of the texture structure, the collector grid line in this application is not approximately parallel to the extension direction of the texture structure, thereby reducing the interference and influence of the texture structure on the extension direction of the printed collector grid line, thereby improving the linearity of the collector grid line.

[0006] In addition, along the extension direction of the collector grid line, the first texture structure located in the edge area has a first distribution density, and the second texture structure located in the middle area has a second distribution density. Along the extension direction of the collector grid line, the first distribution density of the first texture structure in the edge area is greater than the second distribution density of the second texture structure in the middle area. Since the movement speed of the scraper corresponding to the starting position or the retracting position of the edge area is slower when the collector grid line is printed, more collector grid line slurry is printed. By adjusting the first distribution density of the first texture structure in the edge area to be higher than the second distribution density of the second texture structure in the middle area, the roughness of the edge area is increased compared to the roughness of the middle area on the extension path of the collector grid line. The increased roughness of the edge area is conducive to slowing down the fluidity of the slurry, thereby improving the linearity of the collector grid line on the edge area. Collector grid lines with better linearity can reduce series resistance, improve efficiency, and increase the light-receiving area.

[0007] In some possible implementations, the length of the edge region in the first direction is less than or equal to 15% of the length of the solar cell. Since the roughness of the edge region has a significant impact on the printing quality and linearity of the collector grid lines, if the proportion of the edge region is greater than 15%, the proportion of the edge region is too large. Since the roughness of the edge region of the present application is increased after adjustment, if the proportion of the edge region is too large, the passivation performance of the film layer of the semiconductor substrate will be significantly affected. Therefore, considering the impact of the edge region on the linearity of the collector grid lines and the passivation performance of the solar cell, the proportion of the edge region is selected to be less than or equal to 15%.

[0008] In some possible implementations, the angle between the first direction and the second direction is 70° to 115°. This allows the collector grid line to extend in the first direction, or be perpendicular to the first and second texture structures (the second direction). This reduces the overlap between the printed collector grid line and the texture structure along the collector grid line's extension direction, further minimizing the effect of the texture structure on the collector grid line's linearity and improving the collector grid line's linearity.

[0009] In some possible implementations, the first texture structure and the second texture structure both include multiple tower base structures recessed into the semiconductor substrate, and the bottom surface of the tower base structure is a polygonal plane; wherein the multiple tower base structures are continuously arranged along the second direction and at least partially stacked to form a tower base string.

[0010] When using the above technical solution, the tower base structure is recessed inward relative to the surface of the semiconductor substrate. The tower base structure has a non-pyramid-shaped microstructure morphology, with a certain degree of roughness and light-trapping effect, which is beneficial for the absorption of sunlight and improves the photoelectric conversion efficiency. At the same time, compared with the pyramid-shaped structure, the tower base structure has a relatively better surface flatness, which is beneficial for the passivation of the semiconductor substrate and can achieve both passivation and light absorption. Multiple tower base structures are arranged continuously along the second direction, and adjacent tower base structures are at least partially stacked to form a tower base string. The extension direction of the tower base string is the extension direction of the first texture structure and the second texture structure.

[0011] In some possible implementations, a tower base structure with a recessed depth greater than or equal to 0.1 μm is defined as a first target tower base structure; within a unit area, along the extension direction of the collector grid line, the number of first target tower base structures located in the edge area is greater than the number of first target tower base structures located in the middle area. Since the number of first target tower base structures within a unit area reflects the distribution density of the texture structure, the greater the number, the greater the distribution density; therefore, by increasing the number of first tower base structures in the edge area, increasing the first distribution density of the first texture structure in the edge area, it is beneficial to further improve the linearity of the collector grid line in the edge area. The tower base structure with a recessed depth greater than or equal to 0.1 μm is selected as the first target tower base structure for quantitative statistics. If the recessed depth is less than 0.1 μm, the recessed depth of the tower base structure is too small, and the impact on the roughness is small, and the impact on the linearity of the collector grid line is negligible.

[0012] In some possible implementations, tower base structures with a recessed depth greater than or equal to 0.2 μm are defined as second target tower base structures. Within a unit area, along the extension direction of the collector grid line, the number of second target tower base structures located in the edge region is greater than the number of second target tower base structures located in the middle region. Tower base structures with a recessed depth greater than or equal to 0.2 μm are selected as second target tower base structures for quantitative analysis. As the recessed depth increases, the impact on roughness becomes more pronounced, and thus the impact on the linearity of the collector grid line becomes more pronounced.

[0013] In some possible implementations, along the extension direction of the collector grid line, within a unit length, the number of tower base strings located in the edge area is greater than the number of tower base strings located in the middle area; wherein, the number of tower base structures in the tower base string is greater than or equal to 5, and the recessed depth of at least one tower base structure in the tower base string is greater than or equal to 0.1 μm. Since within a unit length along the extension direction of the collector grid line, the number of tower base strings located in the edge area is greater than the number of tower base strings located in the middle area, within a unit length, the number of tower base strings can also reflect the distribution density of the texture structure, and the more tower base strings there are, the greater the distribution density. Therefore, on the extension path of the collector grid line, by increasing the number of tower base strings in the edge area, the first distribution density of the first texture structure in the edge area is increased, which is beneficial to further improve the linearity of the collector grid line in the edge area. The tower base string is formed by continuously stacking more than or equal to 5 tower base structures, which can be observed as a whole, and it is more convenient to count the number of tower base strings. A tower base string with at least one tower base structure having a recessed depth greater than or equal to 0.1 μm is selected for quantitative statistics. If the recessed depth is less than 0.1 μm, the recessed depth of the tower base structure is too small, and the tower base string has little effect on the roughness and a negligible effect on the linearity of the collector grid line.

[0014] In some possible implementations, within a unit length in the first direction, the number of tower base strings located in the edge area is 25 to 35.

[0015] And / or, within a unit length in the first direction, the number of tower base strings located in the middle area is 15 to 25.

[0016] When the above technical solution is adopted, since the first texture structure and the second texture structure both extend along the second direction, the first direction and the second direction intersect. Therefore, by selecting the statistics of the tower base strings within the first direction per unit length in the edge area and the middle area, the number of tower base strings can be clearly observed. Since the texture structure distribution density in each area of ​​the edge area or the middle area is not much different; therefore, by measuring the number of tower base strings in the edge area and the middle area within a suitable unit length, the first distribution density of the first texture structure in the edge area and the second distribution density of the second texture structure in the middle area can be reflected. If the number of tower base strings per unit length in the edge area is less than 25, the first distribution density of the first texture structure in the edge area is too small, which is not conducive to increasing the roughness of the edge area and has little effect on improving the linearity of the collector grid line. If the number of tower base strings per unit length in the edge area is greater than 35, the first distribution density of the first texture structure in the edge area is too large, resulting in excessive roughness in the edge area, making the fluidity of the collector grid line printing too small, which is not conducive to the continuous printing and forming of the collector grid line in the edge area, avoiding the poor passivation effect of the semiconductor substrate surface film layer caused by excessive roughness. Therefore, considering the need to improve the linearity of the collector grid lines in the edge regions, the printing quality of the collector grid lines, and the passivation performance, the number of tower base strings per unit length in the edge regions is selected to be 25 to 35. The number of tower base strings per unit length in the middle region is selected to be 15 to 25, which can match the printing speed of the collector grid lines in the middle region and improve the linearity of the collector grid lines in the middle region.

[0017] In some possible implementations, in the direction perpendicular to the second direction, the spacing between two adjacent tower base strings is 15μm~50μm. That is, in the extension direction perpendicular to the tower base string, the arrangement spacing of two adjacent tower base strings is 15μm~50μm. The smaller the arrangement spacing, the greater the distribution density of the texture structure; conversely, the smaller the distribution density. If the spacing is less than 15μm, the tower base strings are arranged too densely, and the distribution density of the texture structure is too large, resulting in excessive roughness in the edge area, making the fluidity of the collector grid line printing too small, which is not conducive to the continuous printing and forming of the collector grid line in the edge area. In addition, excessive roughness will lead to poor surface passivation effect. If the spacing is greater than 50μm, the arrangement density of the tower base strings is too small, which is not conducive to increasing the roughness of the edge area and has little effect on improving the linearity of the collector grid line.

[0018] In some possible implementations, the one-dimensional dimension of the bottom surface of the tower base structure is 15μm to 50μm. This range helps prevent excessive roughness caused by a smaller one-dimensional dimension, thereby improving surface passivation performance. It also prevents excessive roughness caused by a larger one-dimensional dimension. Excessively small roughness can increase the fluidity of the slurry and hinder the linearity of the collector grid lines.

[0019] In some possible implementations, perpendicular to the second direction, the first spacing between at least two adjacent tower base strings in the edge region is smaller than the second spacing between at least two adjacent tower base strings in the middle region. The smaller the arrangement spacing between two adjacent tower base strings, the greater the distribution density of the texture structure; conversely, the smaller the distribution density. Therefore, by adjusting the first spacing between at least two adjacent tower base strings in the edge region to be smaller than the second spacing between at least two adjacent tower base strings in the middle region, the first distribution density of the first texture structure in the edge region is made greater than the second distribution density of the second texture structure in the middle region, so as to further improve the linearity of the collector grid line in the edge region.

[0020] In some possible implementations, the target surface has a first doping region and a second doping region, the first doping region and the second doping region are alternately arranged along the second direction, and the first doping region and the second doping region have opposite conductivity types; The distribution density of the first texture structure located in the first doping region is different from the distribution density of the first texture structure located in the second doping region; The distribution density of the second texture structure located in the first doping region is different from the distribution density of the second texture structure located in the second doping region.

[0021] When the above technical solution is adopted, since the conductivity types of the first doping region and the second doping region are opposite, and usually the conductivity strengths of the first doping region and the second doping region are different, the doping region with weaker conductivity requires more collector gate contact area to reduce the transmission resistance. Therefore, by increasing the roughness of the doping region, that is, increasing the distribution density of the texture structure of the doping region, the contact area between the collector gate and the doping region can be increased, the transmission resistance can be reduced, and the current collection capacity can be improved. Therefore, the distribution density of the first texture structure located in the first doping region is different from the distribution density of the first texture structure located in the second doping region; the distribution density of the second texture structure located in the first doping region is different from the distribution density of the second texture structure located in the second doping region.

[0022] In some possible implementations, the first doping region is a P-type doping region, and the second doping region is an N-type doping region; the distribution density of the first texture structure located in the P-type doping region is greater than the distribution density of the first texture structure located in the N-type doping region; the distribution density of the second texture structure located in the P-type doping region is greater than the distribution density of the second texture structure located in the N-type doping region. Since the doping concentration of the P-type doping region is lower and the doping concentration of the N-type doping region is higher, the conductivity of the P-type doping region is relatively weak, and the conductivity of the N-type doping region is stronger; therefore, the P-type doping region with weaker conductivity requires more collector gate contact area to reduce the transmission resistance. Therefore, by increasing the roughness of the P-type doping region, that is, increasing the distribution density of the texture structure of the P-type doping region, the contact area between the collector gate and the P-type doping region can be increased, the transmission resistance can be reduced, and the current collection capability can be improved.

[0023] In some possible implementations, the target surface has a P-type doping region and an N-type doping region, and the P-type doping region and the N-type doping region are alternately arranged along the second direction; the distribution density of the first texture structure located in the P-type doping region is greater than the distribution density of the second texture structure located in the P-type doping region; the distribution density of the first texture structure located in the N-type doping region is greater than the distribution density of the second texture structure located in the N-type doping region.

[0024] When using the above technical solution, within the same type of doped region, the distribution density of the first texture structure located at the edge region is compared with the distribution density of the second texture structure located in the middle region. This allows the linearity of the collector gate line at the edge region to be improved by increasing the roughness of the collector gate line relative to the middle region in the doped region through which the collector gate line passes.

[0025] In some possible implementations, the target surface has a P-type doped region and an N-type doped region, and the P-type doped region and the N-type doped region are alternately arranged along the second direction; in the same tower base string, the one-dimensional size of the bottom surface of the tower base structure located in the N-type doped region is larger than the one-dimensional size of the bottom surface of the tower base structure located in the P-type doped region.

[0026] When using the above technical solution, the larger the one-dimensional size of the tower base structure's bottom surface, the smaller the density of the texture structure. Therefore, in order to increase the density of the texture structure in the less conductive P-type doped region, thereby increasing the contact area between the collector grid and the P-type doped region, reducing transmission resistance, and improving current collection capacity, it is necessary that within the same tower base string, the one-dimensional size of the tower base structure's bottom surface in the P-type doped region be smaller than the one-dimensional size of the tower base structure's bottom surface in the N-type doped region.

[0027] In some possible implementations, the target surface has a P-type doped region and an N-type doped region, and the P-type doped region and the N-type doped region are arranged alternately along the second direction; the collector grid line includes a first collector grid line and a second collector grid line, the first collector grid line is correspondingly arranged in the P-type doped region, and the second collector grid line is correspondingly arranged in the N-type doped region; in a direction perpendicular to the first direction, the width of the first collector grid line is greater than the width of the second collector grid line. Since the doping concentration of the P-type doped region is lower and the doping concentration of the N-type doped region is higher, the conductivity of the P-type doped region is relatively weak, and the conductivity of the N-type doped region is stronger; therefore, the P-type doped region with weaker conductivity requires more collector grid line contact area to reduce the transmission resistance. Therefore, by setting a relatively wider first collector grid line on the P-type doped region, the collector grid line contact area can be increased, the transmission resistance can be reduced, and the current collection capacity of the P-type doped region can be improved.

[0028] In some possible implementations, a silicon nitride film layer is provided on the target surface. The silicon nitride film layer can improve the roughness of the texture structure and affect the fluidity of the electrode slurry on the surface of the semiconductor substrate. Accordingly, the thicker the silicon nitride film layer, the smaller the roughness of the texture structure, and the thinner the silicon nitride film layer, the less likely it will reduce the roughness of the texture structure. If the roughness is too small, it will not be conducive to improving the linearity of the collector grid line. If the roughness is too large, it will reduce the passivation effect of the solar cell. By reasonably setting the thickness of the silicon nitride film layer on the target surface, the silicon nitride film layer can meet both the passivation effect and the roughness requirements, thereby improving the linearity of the collector grid line.

[0029] In a second aspect, the present invention further provides a photovoltaic module, comprising: A battery string, wherein the battery string is formed by electrically connecting a plurality of solar cells as described in any one of the above items; an interconnection member electrically connected to the solar cell; and an encapsulation layer covering the surface of the battery string.

[0030] Since the photovoltaic assembly includes the solar cell of the first aspect, it has the same beneficial effects as the first aspect, which will not be described in detail. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings: Figure 1 A schematic diagram of the distribution of a first texture structure in a local edge region of a solar cell provided by an embodiment of the present invention; Figure 2 A schematic diagram of the distribution of a local second texture structure in the middle region of a solar cell provided by an embodiment of the present invention; Figure 3 A schematic diagram showing the distribution of edge and middle regions of a solar cell provided by an embodiment of the present invention; Figure 4 A schematic diagram of the distribution of the edge area of ​​a solar cell provided by an embodiment of the present invention; Figure 5 A three-dimensional image of a first texture structure of a solar cell provided by an embodiment of the present invention; Figure 6 A three-dimensional image of a first texture structure of a P-type doped region of a solar cell provided by an embodiment of the present invention; Figure 7 A three-dimensional image of a first texture structure of an N-type doped region of a solar cell provided by an embodiment of the present invention; Figure 8 A schematic diagram of one-dimensional dimensions of a tower base structure of a solar cell provided by an embodiment of the present invention; Figure 9 Another schematic diagram of one-dimensional dimensions of a tower base structure of a solar cell provided by an embodiment of the present invention; Figure 10 Another schematic diagram of the one-dimensional size of a tower base structure of a solar cell provided by an embodiment of the present invention.

[0032] Figure numerals: 100 is the first texture structure, 110 is the tower base structure, 200 is the second texture structure, 300 is the collector grid line, 310 is the first collector grid line, 320 is the second collector grid line, 400 is the semiconductor substrate, 101 is the first doping region, and 102 is the second doping region. DETAILED DESCRIPTION

[0033] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0034] It should be noted that when an element is referred to as being “fixed on” or “disposed on” another element, it may be directly on the other element or indirectly on the other element. When an element is referred to as being “connected to” another element, it may be directly connected to the other element or indirectly connected to the other element.

[0035] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of the technical features indicated. Thus, a feature specified as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, "plurality" means two or more, unless otherwise specifically defined. "Several" means one or more, unless otherwise specifically defined.

[0036] In the description of the present invention, it should be understood that the terms "up", "down", "front", "back", "left", "right", etc., indicating directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as a limitation on the present invention.

[0037] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediate medium; and may encompass internal communication between two components or interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0038] like Figure 1-Figure 7 As shown, an embodiment of the present invention provides a solar cell including a semiconductor substrate 400 and a collector grid line 300. The semiconductor substrate 400 has two opposing surfaces, and the collector grid line 300 is disposed on at least one surface of the semiconductor substrate 400. The surface of the semiconductor substrate 400 on which the collector grid line 300 is disposed is a target surface. Along the extension direction of the collector grid line 300, the target surface includes an edge region A and a middle region B arranged along a first direction, with the middle region B located between the two edge regions A. The extension direction of the collector grid line 300 is the first direction, i.e., the target surface of the semiconductor substrate 400 is sequentially divided into an edge region A, a middle region B, and an edge region A along the extension direction of the collector grid line 300. The edge region A includes a plurality of first texture structures 100 extending along a second direction, and the plurality of first texture structures 100 are arranged along the first direction. The middle region B includes a plurality of second texture structures 200 extending along the second direction, and the plurality of second texture structures 200 are arranged along the first direction. Along the extension direction of the collector grid line 300 , the first texture structure 100 located in the edge area A has a first distribution density, and the second texture structure 200 located in the middle area B has a second distribution density, the first distribution density is greater than the second distribution density; the first direction intersects the second direction.

[0039] When using the above technical solution, in a first direction (the extension direction of the collector grid line 300), the surface of the semiconductor substrate 400 provided with the collector grid line 300, i.e., the target surface, is divided into edge regions A located on both sides and a middle region B located between the two edge regions A. The extension direction (second direction) of the first texture structure 100 in the edge region A and the second texture structure 200 in the middle region B both intersect with the extension direction (first direction) of the collector grid line 300, i.e., they are not approximately parallel or parallel. Compared to existing structures in which the extension direction of the collector grid line is approximately parallel to the extension direction of the texture structure, the collector grid line 300 in this application is not approximately parallel or parallel to the extension direction of the texture structure. This reduces the interference and influence of the first texture structure 100 and the second texture structure 200 on the extension direction of the printed collector grid line 300, thereby improving the linearity of the collector grid line 300.

[0040] Furthermore, the applicant's research has found that when the collector grid lines in this application extend in a direction that is not approximately parallel or parallel to the direction of the texture structure, the printing quality of the collector grid lines in the edge region is poor, and the linearity of the collector grid lines needs to be further improved. The applicant's research has found that improving the first distribution density of the first texture structure 100 in the edge region A can improve the linearity of the collector grid lines 300 in the edge region A. Therefore, the applicant adjusted the first distribution density of the first texture structure 100 in the edge region A to be greater than the second distribution density of the second texture structure 200 in the middle region B. Because the movement speed of the scraper at the starting or ending position of the edge region corresponding to the collector grid line is slower during printing, more collector grid line paste is printed. By adjusting the first distribution density of the first texture structure 100 in the edge region A to be higher than the second distribution density of the second texture structure 200 in the middle region B, the roughness of the edge region A is increased compared to the roughness of the middle region B. The increased roughness of the edge region A helps to slow down the fluidity of the collector grid line paste, reducing the possibility of the printed collector grid line paste deviating and bifurcating to both sides of the extension direction, thereby improving the linearity of the collector grid line 300 in the edge region A. The collector grid line 300 with better linearity can reduce the series resistance because the bending of the collector grid line is reduced, thereby reducing the coverage of the curved collector grid line on the surface of the solar cell, thereby increasing the light-receiving area and improving the conversion efficiency.

[0041] When the above technical solution is adopted, different microstructures in different areas of the surface, such as different line mark morphology distributions, can be obtained by adjusting the cutting process of the semiconductor substrate, such as the cutting line speed, cutting feed speed, etc. The obtained line mark morphology distribution is converted into a texture structure distribution after etching during battery preparation. In addition, by adjusting the etching process during battery preparation, different etching processes can be used for the edge area and the middle area of ​​the silicon substrate to obtain the texture structure distribution required by this application.

[0042] It should be noted that in actual applications, semiconductor substrate 400 may include a semiconductor base and various functional layers disposed on the semiconductor base. The semiconductor base may be made of any semiconductor material, such as a silicon base, a silicon-germanium base, a germanium base, or a gallium arsenide base. The functional layers may include at least one of a doped semiconductor layer, a passivation layer, an anti-reflective layer, and a transparent conductive layer. The combination of different functional layers and their stacking distribution on the semiconductor base are selected based on the type of solar cell. The semiconductor base may be made of materials such as N-type or P-type single crystal silicon, polycrystalline silicon, or microcrystalline silicon. The materials of the doped semiconductor layer may include doped single crystal silicon, doped polycrystalline silicon, doped microcrystalline silicon, doped nanocrystalline silicon, and doped amorphous silicon. The materials and doping types of the semiconductor base and doped semiconductor layer are appropriately selected based on the cell type. For example, if the doped semiconductor layer is doped polycrystalline silicon, it may form a tunneling passivation contact structure with a tunneling oxide layer. If the doped semiconductor layer is doped amorphous silicon, it may form a heterojunction contact structure with intrinsic amorphous silicon. The resulting solar cell may have a tunneling passivation contact structure and / or a heterojunction contact structure, without specific limitations herein.

[0043] The above-mentioned solar cell can be a double-sided solar cell, that is, collector grid lines are arranged on both surfaces of the semiconductor substrate, wherein the positive collector grid line is arranged on one surface of the semiconductor substrate and the negative collector grid line is arranged on the other surface of the semiconductor substrate; or, the solar cell can be a back-contact cell, that is, the positive collector grid line and the negative collector grid line are both arranged on the same surface of the semiconductor substrate, that is, the back surface.

[0044] The collector grid lines extend along a first direction, and multiple collector grid lines are arranged along a second direction. For back-contact cells, the collector grid lines on the back side include positive collector grid lines and negative collector grid lines, corresponding to different conductivity doping regions on the back side, and are arranged alternately. For bifacial solar cells, the collector grid lines on the same side have the same polarity and are arranged in an alternating pattern.

[0045] In some embodiments, in the first direction, the length of the edge region A is less than or equal to 15% of the overall length of the solar cell, and correspondingly, the length of the middle region B is greater than 85% of the overall length of the solar cell. Specifically, the proportions of the two edge regions A can be 5%, 10%, 12%, 15%, etc. Since the roughness of the edge region A has a great impact on the printing quality and linearity of the collector grid line 300. If the proportion of the edge region A is greater than 15%, the proportion of the edge region A is too large. Since the roughness of the edge region A of the present application increases after adjustment, if the proportion of the edge region A is too large, the film passivation performance of the semiconductor substrate 400 will be greatly affected. Therefore, considering the influence of the edge region A on the linearity of the collector grid line 300 and the passivation performance of the solar cell, the proportion of the edge region A is selected to be less than or equal to 15%. It should be noted that the area where each collector grid line 300 is located has an edge area and a middle area in the extension direction of the collector grid line 300. Figures 1-4 The edge region A shown in FIG refers to a set of edge regions where multiple collector gate lines 300 are located. Figures 1-4 The middle region B shown in FIG. 1 refers to a set of middle regions where the plurality of collector gate lines 300 are located.

[0046] like Figure 1-Figure 3 As shown, in some embodiments, the angle between the first direction and the second direction is 70° to 115°, specifically 70°, 75°, 80°, 85°, 86°, 87°, 88°, 89°, 90°, 95°, 100°, 105°, 110°, 115°, etc. In this way, the extending direction (first direction) of the collector grid line 300 is approximately perpendicular or perpendicular to the extending direction (second direction) of the first texture structure 100 and the second texture structure 200, thereby further reducing the adverse effect of the texture structure on the linearity of the collector grid line 300 and improving the linearity of the collector grid line 300.

[0047] like Figure 1 、 Figure 2 、 Figure 5-Figure 7As shown, in some possible implementations, the first texture structure 100 and the second texture structure 200 both include a plurality of tower base structures 110 recessed into the semiconductor substrate 400. Regardless of the functional layers of the semiconductor substrate 400, the final morphology presented on the surface of the semiconductor substrate 400 is a plurality of tower base structures 110 recessed into the semiconductor substrate 400. The bottom surface of the tower base structure 110 is a polygonal plane, and the shape of the polygonal plane includes at least one of a rectangle, a rhombus, a square, a trapezoid, an approximate rectangle, an approximate rhombus, an approximate square, and an approximate trapezoid. Among them, the plurality of tower base structures 110 are arranged continuously along the second direction, and the adjacent tower base structures 110 are at least partially stacked to form a tower base string. It is understandable that in the actual manufacturing process, the bottom surface morphology of the tower base structure 110 presents an irregular polygonal plane, but generally presents morphological features similar to a rhombus, a square, and a trapezoid.

[0048] In some embodiments, a silicon nitride film layer is provided on the target surface of the semiconductor substrate 400, that is, at least a silicon nitride film layer is provided on the surface of the semiconductor substrate, and the silicon nitride film layer serves as a passivation layer. When preparing a solar cell, a silicon nitride film layer can be first formed on the surface of the semiconductor substrate, and then a collector grid line can be formed after the silicon nitride film layer is formed, or a doped semiconductor layer and a silicon nitride film layer can be first formed on the surface of the semiconductor substrate, and then a collector grid line can be formed on the silicon nitride film layer. The silicon nitride film layer can improve the roughness of the texture structure on the surface of the semiconductor substrate and the degree of wetting with the electrode slurry, affecting the fluidity of the electrode slurry on the surface of the semiconductor substrate. The thicker the silicon nitride film layer, the more uniform and flat the surface covered by the silicon nitride film layer, so that the roughness of the texture structure is reduced. The thinner the silicon nitride film layer, the more it can change with the surface shape of the texture structure, and the less it will reduce the roughness of the texture structure. If the roughness is too small, it is not conducive to improving the linearity of the collector grid line. If the roughness is too large, it will reduce the passivation effect of the solar cell. By properly setting the thickness of the silicon nitride film on the target surface, the silicon nitride film can meet both the passivation effect and the roughness requirements, thereby improving the linearity of the collector grid line. For example, the thickness of the silicon nitride film can be 50-100 nm.

[0049] When the above technical solution is adopted, the tower base structure 110 is recessed inward relative to the surface of the semiconductor substrate 400. The tower base structure 110 has a non-pyramid-shaped microstructure morphology. The morphology formed by multiple tower base structures 110 has a certain degree of roughness and light trapping effect, which is beneficial to the absorption of sunlight and improves the photoelectric conversion efficiency. At the same time, compared with the morphological characteristics of the pyramid structure, the surface flatness of the tower base structure 110 is relatively good, which is beneficial to the passivation of the semiconductor substrate 400, and can take into account both the passivation effect and light absorption, thereby optimizing the battery conversion efficiency. Multiple tower base structures 110 are continuously arranged along the second direction and adjacent tower base structures 110 are at least partially stacked to form a tower base string. The extension direction of the tower base string is the extension direction of the first texture structure 100 and the second texture structure 200. Figure 1 、 Figure 2 、 Figure 5-Figure 7 It can be seen that the extending direction of the collector grid line 300 is approximately perpendicular or vertical to the extending direction of the tower base string.

[0050] In some embodiments, the distribution density of the first texture structure 100 and the second texture structure 200 can be determined by defining a tower base structure 110 with a recess depth greater than or equal to 0.1 μm as a first target tower base structure; and within a unit area, along the extension direction of the collector grid line 300, the number of first target tower base structures located in the edge region A is greater than the number of first target tower base structures located in the middle region B. The unit area can be any unit rectangular area within the edge region A and the middle region B, within the extension region of the collector grid line 300, or within the extension region adjacent to the collector grid line 300. The unit area can be (0.5 mm to 5 mm) × (0.5 mm to 5 mm), and the length and width of the unit area can be any combination, such as 0.5 mm × 0.5 mm, 1 mm × 1 mm, 5 mm × 5 mm, etc. The unit area selected in the edge region A is equal to the unit area selected in the middle region B. The recessed depth of the tower base structure 110 refers to the height value between the bottom of the tower base structure 110 of the battery and the edge of the tower base structure 110; in actual measurement, the recessed depth of the tower base structure 110 can be the height value measured between the bottom of the tower base structure on the surface of the silicon substrate and the edge of the tower base structure. Since the film thickness on the surface of the semiconductor substrate is very small, it can also be the height value directly measured between the bottom of the tower base structure 110 on the surface of the battery and the edge of the tower base structure 110. Within a unit area, the number of first target tower base structures reflects the distribution density of the texture structure. The more the number of first target tower base structures, the greater the distribution density. Therefore, by increasing the number of first target tower base structures in the edge area A, the first distribution density of the first texture structure 100 in the edge area A is increased, which is beneficial to further improve the linearity of the collector grid line 300 in the edge area A. The tower base structure 110 with a recessed depth greater than or equal to 0.1 μm is selected as the first target tower base structure for quantitative statistics. If the recessed depth is less than 0.1 μm, the recessed depth of the tower base structure 110 is too small, has little effect on the roughness, and has a negligible effect on the linearity of the collector grid line 300, and is not included in the statistical range.

[0051] In some embodiments, a tower base structure 110 with a recessed depth greater than or equal to 0.2 μm is defined as a second target tower base structure; within a unit area, along the extension direction of the collector grid line 300, the number of second target tower base structures located in the edge area A is greater than the number of second target tower base structures located in the middle area B. The tower base structures 110 with a recessed depth greater than or equal to 0.2 μm are selected as the second target tower base structures for quantitative statistics. The further the recessed depth increases, the more obvious the impact on the roughness, and thus the more significant the impact on the linearity of the collector grid line. Of course, tower base structures 110 with a recessed depth greater than or equal to 0.25 μm, 0.3 μm, 0.4 μm, etc. can also be selected for quantitative statistics. By controlling the distribution of tower base structures with greater influence, the linearity of the collector grid line 300 can be controlled.

[0052] In other embodiments, the distribution density of the first texture structure 100 and the second texture structure 200 can also be presented in the following manner: Figure 1 、 Figure 2 、 Figure 5-Figure 7 As shown, within a unit length in the collector grid line extension direction, the number of tower base strings located in the edge region A is greater than the number of tower base strings located in the middle region B. The number of tower base structures 110 in the tower base string is greater than or equal to five, and the recessed depth of at least one tower base structure 110 in the tower base string is greater than or equal to 0.1 μm. Because the first direction intersects with the extension direction (second direction) of the first texture structure 100 and the second texture structure 200, and is preferably approximately perpendicular to the extension direction of the tower base string, it can be understood that the multiple tower base strings are arranged along the first direction. Therefore, during observation and statistics, the number of tower base strings in the edge region A and the number of tower base strings in the middle region B are counted within a unit length in the first direction. The unit length selected in the edge region A is equal to the unit length selected in the middle region B. The unit length can be a unit distance selected along the extension direction of the collector grid line 300, or in the area adjacent to the collector grid line 300. Since the number of tower base strings within the unit length of the first direction can also reflect the distribution density of the texture structure, the more tower base strings there are, the greater the distribution density. Therefore, by increasing the number of tower base strings in the edge area A in the extension direction of the collector grid line 300, the first distribution density of the first texture structure 100 in the edge area A is increased, which is conducive to further improving the linearity of the collector grid line 300 in the edge area A. In addition, the tower base string is formed by continuously stacking more than or equal to 5 tower base structures 110, which can be observed as a whole, making it more convenient to observe and count the number of tower base strings. During actual observation and measurement, the recessed depth of a certain tower base structure 110 in the tower base string can be measured. As long as the recessed depth of the tower base structure 110 is greater than or equal to 0.1μm, the tower base string can be counted. If the recessed depth of the tower base structure 110 of the tower base string is less than 0.1μm, the recessed depth of the tower base structure 110 is too small, the tower base string has little effect on the roughness, and has little effect on the linearity of the collector grid line 300. Of course, tower base strings with 6, 7, 8, 9, 10, or more tower base structures 110 stacked in a row may also be used as statistical objects. Alternatively, a concave depth of at least one tower base structure 110 in the tower base string greater than or equal to 0.2 μm, 0.3 μm, 0.4 μm, or the like may be used as a statistical standard.

[0053] In some embodiments, within a unit length in the first direction, the number of tower base strings located in edge region A is 25-35, specifically 25, 27, 29, 31, 33, or 35. For example, within edge region A, a measurement region with a length of 840.8 μm is selected along the extending direction of collector grid line 300. Randomly selected measurement regions within the edge region contain 25-35 tower base strings.

[0054] For example, the unit length in the first direction can also be any length of 830μm~900μm, specifically 830μm, 840μm, 850μm, 860μm, 870μm, 880μm, 890μm, etc. Correspondingly, the number of tower base strings counted in the edge area A is different, and the actual measurement shall prevail.

[0055] Similarly, within a unit length in the first direction, the number of tower base strings located in the middle region B is 15 to 25. For example, within the middle region B, a measurement area with a length of 840.8 μm is selected along the extension direction of the collector grid line 300. Different measurement areas in the middle region are randomly selected, and the number of tower base strings counted within this measurement area is 15 to 25, specifically 15, 17, 19, 21, 23, or 25. It should be noted that the unit length selected within the edge region A is equal to the unit length selected within the middle region B.

[0056] For example, the unit length along the extension direction of the collector grid line 300 can also be any length of 830μm~900μm, specifically 830μm, 840μm, 850μm, 860μm, 870μm, 880μm, 890μm, etc. Correspondingly, the number of tower base strings counted in the middle area B is different, and the actual measurement shall prevail.

[0057] When adopting the above technical solution, since the first texture structure 100 and the second texture structure 200 both extend along the second direction and the first direction and the second direction intersect, the statistics of the tower base strings are performed within the unit length in the first direction in the edge area A and the middle area B, and the number of tower base strings can be clearly observed. Since the texture structure distribution density in each area of ​​the edge area A or the middle area B is not much different, by measuring the number of tower base strings in the edge area A and the tower base strings in the middle area B within a suitable unit length, the distribution density of the first texture structure 100 in the edge area A and the second texture structure 200 in the middle area B along the extension direction of the collector grid line 300 can be reflected. If the number of tower base strings per unit length of the edge region A is less than 25, the first distribution density of the first texture structure 100 in the edge region A is too small, which is not conducive to increasing the roughness of the edge region A and has little effect on improving the linearity of the collector grid line 300; if the number of tower base strings per unit length of the edge region A is greater than 35, the first distribution density of the first texture structure 100 in the edge region A is too large, resulting in excessive roughness of the edge region A, making the fluidity of the collector grid line printing too small, which is not conducive to the continuous printing and forming of the collector grid line 300 in the edge region A. At the same time, the above scheme can avoid the poor passivation effect of the semiconductor substrate surface film layer caused by excessive roughness. Therefore, considering improving the linearity of the collector grid line 300 in the edge region A, the printing and forming quality of the collector grid line 300, and the passivation performance, the number of tower base strings per unit length of the edge region A is selected to be 25 to 35. The number of tower base strings per unit length in the middle region B is 15 to 25, which can match the printing speed of the collector grid line 300 in the middle region B and improve the linearity of the collector grid line 300 in the middle region B.

[0058] like Figure 1 and Figure 2As shown, in some embodiments, the spacing between two adjacent tower base strings perpendicular to the second direction is 15μm to 50μm. That is, in the direction perpendicular to the extension of the tower base strings, the arrangement spacing between two adjacent tower base strings is 15μm to 50μm. For example, the spacing between two adjacent tower base strings can be 15μm, 18μm, 20μm, 22μm, 24μm, 26μm, 28μm, 30μm, 32μm, 34μm, 36μm, 38μm, 40μm, 42μm, 44μm, 47μm, 50μm, etc. The smaller the arrangement spacing, the greater the distribution density of the texture structure, and vice versa. If the spacing is less than 15 μm, the tower base strings are too densely arranged, and the distribution density of the texture structure is too high, resulting in excessive roughness in the edge area A. This reduces the fluidity of the collector grid lines 300 during printing, hindering the continuous printing and forming of the collector grid lines 300 in the edge area A. If the spacing is greater than 50 μm, the tower base string arrangement density is too low, which is not conducive to increasing the roughness of the edge area A and has little effect on improving the linearity of the collector grid lines 300.

[0059] It should be noted that when the first direction and the second direction are perpendicular, the spacing between two adjacent tower base strings is the spacing between the two adjacent tower base strings in the second direction. The spacing between two adjacent tower base strings specifically refers to the distance between the center lines of the two tower base strings.

[0060] like Figure 1 and Figure 2 As shown, in some embodiments, in a direction perpendicular to the second direction, the first spacing d1 between at least partially adjacent two tower base strings located in the edge region A is smaller than the second spacing d2 between at least partially adjacent two tower base strings located in the middle region B. The smaller the arrangement spacing between two adjacent tower base strings, the greater the distribution density of the texture structure, and vice versa. Therefore, by adjusting the first spacing d1 between at least partially adjacent two tower base strings in the edge region A to be smaller than the second spacing d2 between at least partially adjacent two tower base strings in the middle region B, the first distribution density of the first texture structure 100 in the edge region A is made greater than the second distribution density of the second texture structure 200 in the middle region B. By increasing the first distribution density of the first texture structure 100 in the edge region A, the linearity of the collector grid line 300 in the edge region A is further improved.

[0061] For example, the surface of the solar cell is observed under an electron microscope. In the local three-dimensional scanning diagram of the battery surface obtained, taking the unit length of 840.8 μm in the extension direction of the collector grid line 300 as an example, the distribution of the texture structure of the edge area A and the middle area B is measured, wherein the spacing between two adjacent tower base strings is measured by marking the center lines of the two adjacent tower base strings and measuring the distance between the two adjacent center lines; at the same time, the number of tower base strings is counted. It should be noted that in actual measurement, the tower base strings can be observed on the extension path of the collector grid line 300, or in the adjacent area of ​​the extension path of the collector grid line 300; in addition, the unit length can also be selected as needed. This embodiment only gives an example, as shown in Table 1 below: Table 1. Distribution of texture structures in edge and middle areas

[0062] Table 1 shows that the first spacing d1 between at least partially adjacent first texture structures 100 in edge region A is smaller than the second spacing d2 between at least partially adjacent second texture structures 200 in middle region B. Within a unit length, along the extension direction of the collector gate line 300, the first distribution density of the first texture structures 100 in edge region A is greater than the second distribution density of the second texture structures 200 in middle region B. In this example, the spacing between two adjacent first texture structures 100 in edge region A can be selected from the first spacing d1 between two adjacent tower base strings in the P-type doping region of edge region A; the spacing between two adjacent second texture structures 200 in middle region B can be selected from the second spacing d2 between two adjacent tower base strings in the P-type doping region of middle region B. Because a single collector gate line passes through both the edge and middle regions and is located in the same polarity doping region, when performing comparative control, the number and spacing of texture structures in the edge and middle regions of the same polarity doping region can be selected for comparison and control to more accurately reflect the distribution of texture structures in the edge and middle regions, in accordance with the median comparison principle. Of course, when comparing the texture structures of the edge regions and middle regions of doped regions with different polarities, there will be some differences compared with the same polarity doped regions, which are not included in the statistical scope of this embodiment.

[0063] For example, taking the preparation of back-contact batteries as an example, the distribution density of the first texture structure 100 of the P-type doping region in the edge region A is greater than the distribution density of the second texture structure 200 of the P-type doping region in the middle region B. Compared with the battery cell without the above-mentioned features, in the actual mass production process, in this embodiment, the probability of gate breakage is reduced from 1% to 0.3%, and the battery efficiency is increased from 26.51% to 26.56%.

[0064] like Figures 8-10As shown, in some embodiments, the one-dimensional size of the bottom surface of the tower base structure 110 is 15μm~50μm, specifically 15μm, 20μm, 25μm, 30μm, 35μm, 40μm, 45μm, 50μm. Among them, the one-dimensional size of the bottom surface of the tower base structure 110 can specifically be the length, width, diagonal length, diameter of the circle or the distance between the two farthest end points of the bottom surface, etc., which is not limited here. The one-dimensional size of the bottom surface of the tower base structure 110 is within the above range, which is conducive to preventing the one-dimensional size from being too small and causing a large roughness, thereby helping to improve the surface passivation performance, and can also prevent the roughness from being too small due to the large one-dimensional size. Excessive roughness will cause the fluidity of the slurry to increase, which is not conducive to improving the linearity of the collector grid line during printing.

[0065] like Figure 1-Figure 3 As shown, in some embodiments, the target surface of the semiconductor substrate 400 has a first doping region 101 and a second doping region 102, and the first doping region 101 and the second doping region 102 are alternately arranged along the second direction, that is, a collector gate line 300 is provided on the back side of the semiconductor substrate 400, and the back side of the semiconductor substrate 400 has the first doping region 101 and the second doping region 102 alternately arranged along the second direction. The collector gate line 300 includes a first collector gate line 310 and a second collector gate line 320. The first collector gate line 310 and the second collector gate line 320 are respectively arranged on the first doping region 101 and the second doping region 102. The first doping region 101 and the second doping region 102 have opposite conductivity types. The first doping region 101 and the second doping region 102 are distinguished by doped semiconductor layers of different doping types. In some cases, the first doping region 101 and the second doping region 102 can also be physically insulated and isolated by an isolation trench; the distribution density of the first texture structure 100 located in the first doping region 101 is different from the distribution density of the first texture structure 100 located in the second doping region 102; the distribution density of the second texture structure 200 located in the first doping region 101 is different from the distribution density of the second texture structure 200 located in the second doping region 102. The arrangement direction of the first doping region 101 and the second doping region 102 is different from that of the edge region A and the middle region B, and the two are approximately perpendicular. That is, both the edge region A and the middle region B have the first doping region 101 and the second doping region 102.

[0066] Because the first doped region 101 and the second doped region 102 have opposite conductivity types, and generally have different conductivity strengths, the less conductive doped region requires a larger collector gate contact area to reduce transmission resistance. Therefore, by increasing the roughness of the doped region, that is, increasing the distribution density of the texture structure in the doped region, the contact area between the collector gate and the doped region can be increased, thereby reducing transmission resistance and improving current collection capability. Therefore, the distribution density of the first texture structure 100 located in the first doped region 101 is different from the distribution density of the first texture structure 100 located in the second doped region 102, and the distribution density of the second texture structure 200 located in the first doped region 101 is different from the distribution density of the second texture structure 200 located in the second doped region 102. The distribution density of the first texture structure 100 and the second texture structure 200 can be presented as described in the above embodiments, and can be represented by the number of first target tower base structures or second target tower base structures per unit area, or the number of tower base strings per unit length in the first direction. This will not be further described here.

[0067] like Figure 1-Figure 3 As shown, for example, the first doping region 101 is a P-type doping region, and the second doping region 102 is an N-type doping region; the distribution density of the first texture structure 100 in the P-type doping region is greater than the distribution density of the first texture structure 100 in the N-type doping region; and the distribution density of the second texture structure 200 in the P-type doping region is greater than the distribution density of the second texture structure 200 in the N-type doping region. Since the doping concentration of the P-type doping region is lower and the doping concentration of the N-type doping region is higher, the conductivity of the P-type doping region is relatively weak, while the conductivity of the N-type doping region is stronger. Therefore, the P-type doping region with weaker conductivity requires more collector gate contact area to reduce transmission resistance. Therefore, by increasing the roughness of the P-type doping region, that is, increasing the distribution density of the texture structure in the P-type doping region, the contact area between the collector gate and the P-type doping region can be increased, thereby reducing transmission resistance and improving current collection capability.

[0068] Of course, in other embodiments, the first doping region 101 can also be an N-type doping region, and the second doping region 102 can be a P-type doping region. The doping concentration of the N-type doping region is lower, and the doping concentration of the P-type doping region is higher. The conductivity of the N-type doping region is relatively weak, and the conductivity of the P-type doping region is strong. Therefore, the N-type doping region with weaker conductivity requires more collector grid line contact area to reduce the transmission resistance. Therefore, the roughness of the N-type doping region can be increased, that is, the distribution density of the texture structure of the N-type doping region can be increased to increase the contact area between the collector grid line and the N-type doping region, thereby reducing the transmission resistance and improving the current collection capability.

[0069] In some embodiments, the target surface of the semiconductor substrate 400 includes P-type and N-type doped regions, with the P-type and N-type doped regions being arranged alternately along a second direction. The distribution density of the first texture structure 100 in the P-type doped region is greater than the distribution density of the second texture structure 200 in the P-type doped region; and the distribution density of the first texture structure 100 in the N-type doped region is greater than the distribution density of the second texture structure 200 in the N-type doped region. Within doped regions of the same polarity, the distribution density of the first texture structure 100 in the edge region A is compared with the distribution density of the second texture structure 200 in the middle region B. This allows the linearity of the collector gate line 300 in the edge region A to be improved by increasing the roughness of the collector gate line 300 in the edge region A relative to the roughness of the middle region B within the doped region where the collector gate line 300 passes.

[0070] like Figure 6 and Figure 7 As shown, in some embodiments, within the same tower base string (i.e., the same first texture structure 100), the bottom surface one-dimensional dimension of the tower base structure 110 located in the N-type doping region (the second doping region 102) is greater than the bottom surface one-dimensional dimension of the tower base structure 110 located in the P-type doping region (the first doping region 101). For example, the bottom surface one-dimensional dimension of the tower base structure 110, such as the bottom surface length, can be 15μm to 50μm. Within the same tower base string, the bottom surface length of the tower base structure 110 located in the N-type doping region is 25μm to 50μm, and the bottom surface length of the tower base structure 110 located in the P-type doping region is 15μm to 40μm.

[0071] When using the above technical solution, the larger the one-dimensional size of the bottom surface of the tower base structure 110, the smaller the arrangement density of the texture structure. Therefore, in order to increase the arrangement density of the texture structure in the P-type doped region with weaker conductivity, thereby increasing the contact area between the collector grid line and the P-type doped region, reducing the transmission resistance, and improving the current collection capability, the one-dimensional size of the bottom surface of the tower base structure 110 in the P-type doped region within the same tower base string can be adjusted to be smaller than the one-dimensional size of the bottom surface of the tower base structure 110 in the N-type doped region, thereby further increasing the arrangement density of the texture structure in the P-type doped region.

[0072] like Figure 1-Figure 3As shown, in some possible implementations, when the back side of the semiconductor substrate 400 has P-type doping regions and N-type doping regions alternately arranged along the second direction; the collector gate line 300 includes a first collector gate line 310 and a second collector gate line 320, the first collector gate line 310 is correspondingly arranged in the P-type doping region, the second collector gate line 320 is correspondingly arranged in the N-type doping region, the first collector gate line 310 extends along the first direction, the P-type doping region extends along the first direction, the second collector gate line 320 extends along the first direction, and the N-type doping region extends along the first direction; perpendicular to the first direction, the width of the first collector gate line 310 is greater than the width of the second collector gate line 320. Since the doping concentration of the P-type doping region is lower and the doping concentration of the N-type doping region is higher, the conductivity of the P-type doping region is relatively weak, and the conductivity of the N-type doping region is strong. Therefore, the P-type doping region with weaker conductivity requires more collector gate line contact area to reduce the transmission resistance. Therefore, the collector gate line contact area can be increased by setting a relatively wider first collector gate line 310 on the P-type doping region, thereby reducing the transmission resistance and improving the current collection capacity of the P-type doping region.

[0073] like Figure 1 、 Figure 2 and Figure 4 As shown, in some embodiments, Figure 4 , along the second direction, the edge area A on the left is divided into a first edge area A1, a second edge area A2, and a third edge area A3 from top to bottom, and the edge area A on the right is divided into a fourth edge area A4, a fifth edge area A5, and a sixth edge area A6 from top to bottom; The distribution density of the first texture structure 100 in at least part of the first edge region A1 and the third edge region A3 is greater than the distribution density of the first texture structure 100 in at least part of the second edge region A2. The distribution density of the first texture structure 100 in at least part of the fifth edge region A5 is greater than the distribution density of the first texture structure 100 in at least part of the fourth edge region A4 and the sixth edge region A6.

[0074] Based on the solar cells described in any of the above embodiments, embodiments of the present invention further provide a photovoltaic module comprising a cell string, an interconnect, and an encapsulation layer, wherein the cell string is formed by electrically connecting a plurality of solar cells as described in any of the above embodiments; the interconnect is electrically connected to the solar cells; and the encapsulation layer covers the surface of the cell string. The encapsulation layer may include a cover plate and a back plate located on both sides of the cell string, as well as an encapsulation film and other structures for encapsulation. Because this photovoltaic module utilizes the solar cells described in any of the above embodiments, it has the same beneficial effects as any of the above embodiments.

[0075] In the description of the above embodiments, specific features, structures, materials or characteristics may be combined in an appropriate manner in any one or more embodiments or examples.

[0076] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. A solar cell, characterized in that: It comprises a semiconductor substrate and a collector grid line, wherein the surface of the semiconductor substrate on which the collector grid line is provided is a target surface; Along the extension direction of the collector grid line, the target surface has an edge region and a middle region, and the middle region is located between the two edge regions; the extension direction of the collector grid line is a first direction; The edge region has a plurality of first texture structures extending along a second direction, and the middle region has a plurality of second texture structures extending along the second direction; the first direction intersects the second direction; Along the extending direction of the collector grid line, the first texture structure located in the edge region has a first distribution density, and the second texture structure located in the middle region has a second distribution density, and the first distribution density is greater than the second distribution density.

2. The solar cell according to claim 1, wherein In the first direction, the length of the edge region is less than or equal to 15% of the length of the solar cell.

3. The solar cell according to claim 1, wherein The angle between the first direction and the second direction is 70° to 115°.

4. The solar cell according to claim 1, wherein The first texture structure and the second texture structure each include a plurality of tower base structures recessed into the semiconductor substrate; The bottom surface of the tower base structure is a polygonal plane; wherein, a plurality of the tower base structures are continuously arranged along the second direction and at least partially stacked to form a tower base string.

5. The solar cell according to claim 4, wherein Defining the tower base structure having a concave depth greater than or equal to 0.1 μm as a first target tower base structure; Within a unit area, along the extending direction of the collector grid line, the number of the first target tower base structures located in the edge region is greater than the number of the first target tower base structures located in the middle region.

6. The solar cell according to claim 4, characterized in that The tower base structure having a concave depth greater than or equal to 0.2 μm is defined as a second target tower base structure; Within a unit area, along the extending direction of the collector grid line, the number of the second target tower base structures located in the edge region is greater than the number of the second target tower base structures located in the middle region.

7. The solar cell according to claim 4, characterized in that Along the extending direction of the collector grid line, within a unit length, the number of the tower base strings located in the edge area is greater than the number of the tower base strings located in the middle area; The number of the tower base structures in the tower base string is greater than or equal to 5, and the recessed depth of at least one of the tower base structures in the tower base string is greater than or equal to 0.1 μm.

8. The solar cell according to claim 7, characterized in that Within a unit length in the first direction, the number of the tower base strings located in the edge area is 25 to 35; And / or, within a unit length of the first direction, the number of the tower base strings located in the middle area is 15 to 25.

9. The solar cell according to claim 4, wherein: In a direction perpendicular to the second direction, the spacing between two adjacent tower base strings is 15 μm to 50 μm; And / or, a one-dimensional size of the bottom surface of the tower base structure is 15 μm to 50 μm.

10. The solar cell according to claim 4, characterized in that In a direction perpendicular to the second direction, a first spacing between at least two adjacent tower base strings located in the edge region is smaller than a second spacing between at least two adjacent tower base strings located in the middle region.

11. The solar cell according to any one of claims 1 to 10, characterized in that: The target surface has a first doping region and a second doping region, the first doping region and the second doping region are alternately arranged along the second direction, and the first doping region and the second doping region have opposite conductivity types; The distribution density of the first texture structure located in the first doping region is different from the distribution density of the first texture structure located in the second doping region; The distribution density of the second texture structure located in the first doping region is different from the distribution density of the second texture structure located in the second doping region.

12. The solar cell according to claim 11, characterized in that The first doping region is a P-type doping region, and the second doping region is an N-type doping region; The distribution density of the first texture structure located in the P-type doping region is greater than the distribution density of the first texture structure located in the N-type doping region; The distribution density of the second texture structure located in the P-type doping region is greater than the distribution density of the second texture structure located in the N-type doping region.

13. The solar cell according to any one of claims 1 to 10, characterized in that: The target surface has a P-type doping region and an N-type doping region, and the P-type doping region and the N-type doping region are alternately arranged along the second direction; The distribution density of the first texture structure located in the P-type doping region is greater than the distribution density of the second texture structure located in the P-type doping region; The distribution density of the first texture structure located in the N-type doping region is greater than the distribution density of the second texture structure located in the N-type doping region.

14. The solar cell according to any one of claims 4 to 10, characterized in that: The target surface has a P-type doping region and an N-type doping region, and the P-type doping region and the N-type doping region are alternately arranged along the second direction; In the same tower base string, a one-dimensional size of the bottom surface of the tower base structure located in the N-type doping region is larger than a one-dimensional size of the bottom surface of the tower base structure located in the P-type doping region.

15. The solar cell according to any one of claims 1 to 10, characterized in that: The target surface has a P-type doping region and an N-type doping region, and the P-type doping region and the N-type doping region are alternately arranged along the second direction; The collector gate line includes a first collector gate line and a second collector gate line, the first collector gate line is correspondingly arranged in the P-type doping region, and the second collector gate line is correspondingly arranged in the N-type doping region; In a direction perpendicular to the first direction, the width of the first collecting gate line is greater than the width of the second collecting gate line.

16. The solar cell according to any one of claims 1 to 10, characterized in that: A silicon nitride film layer is provided on the target surface.

17. A photovoltaic module, characterized in that: include: A battery string, wherein the battery string is formed by electrically connecting a plurality of solar cells according to any one of claims 1 to 16; an interconnection member, electrically connected to the solar cell; and an encapsulation layer covering the surface of the battery string.

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