Solar cell, manufacturing method thereof and photovoltaic module

Abstract

The invention discloses a solar cell, a manufacturing method thereof and a photovoltaic module, relates to the technical field of photovoltaics, and is used for reducing the frequency of reciprocating motion of laser spots in a patterning treatment process, reducing laser damage, facilitating improvement of the conversion efficiency of the solar cell and improving the productivity of patterning treatment. The solar cell includes a semiconductor substrate and a first doped semiconductor layer. The first doped semiconductor layer is disposed on a local region of the first surface. The first doped semiconductor layer comprises a plurality of first strip-shaped regions which extend along the first direction and are distributed at intervals along the second direction. The first doped semiconductor layer includes a first boundary extending in a first direction and a second boundary extending in a second direction. The first boundary is provided with a plurality of first protruding units which fluctuate in the second direction and are sequentially distributed in the first direction, and the second boundary is provided with a plurality of second protruding units which fluctuate in the first direction and are sequentially distributed in the second direction. The width of the first protruding unit is smaller than that of the second protruding unit.

Description

Technical Field

[0001] This invention relates to the field of photovoltaic technology, and in particular to a solar cell, its manufacturing method, and a photovoltaic module. Background Technology

[0002] A solar cell is a device that converts solar energy into electrical energy. Specifically, when a solar cell is in operation, sunlight shines on the semiconductor pn junction, forming new electron-hole pairs. Under the influence of the built-in electric field of the pn junction, photogenerated holes flow to the p-region, and photogenerated electrons flow to the n-region. When the circuit is connected, an electric current is generated. The doped semiconductor layer, located in the p-region and / or n-region, can be disposed only in a localized area on the corresponding surface of the semiconductor substrate. For example, in a back-contact cell, the N-type and P-type doped semiconductor layers are located only in a localized area on the back of the cell. Another example is the poly-finger structure in a tunneling oxide passivated contact cell.

[0003] However, the conversion efficiency of existing solar cells still needs to be further improved. Summary of the Invention

[0004] The purpose of this invention is to provide a solar cell and its manufacturing method, as well as a photovoltaic module, which is used to pattern the first doped semiconductor layer by using a rectangular light spot with a large length along the second direction. This reduces the number of times the laser spot moves back and forth during the patterning process, reduces the damage to the semiconductor substrate caused by high-temperature laser irradiation, and helps to improve the conversion efficiency of the solar cell. At the same time, it increases the production capacity of the patterning process and improves the manufacturing efficiency of the solar cell.

[0005] To achieve the above objectives, in a first aspect, the present invention provides a solar cell comprising: a semiconductor substrate and a first doped semiconductor layer. The semiconductor substrate includes a first surface and a second surface opposite to each other. The first doped semiconductor layer is disposed on a local region of the first surface. The first doped semiconductor layer includes a plurality of first strip-shaped regions extending along a first direction and spaced apart along a second direction. The first direction is different from the second direction. The first doped semiconductor layer includes a first boundary extending along the first direction and a second boundary extending along the second direction. The first boundary has a plurality of first protruding units undulating towards the second direction and sequentially distributed along the first direction, and the second boundary has a plurality of second protruding units undulating towards the first direction and sequentially distributed along the second direction. The width of the first protruding units is smaller than the width of the second protruding units.

[0006] In the solar cell provided by the present invention, the first doped semiconductor layer is disposed on a local area of ​​the first surface of the semiconductor substrate using the above technical solution. In the actual manufacturing process, a first doped semiconductor layer entirely disposed on the first surface can be formed first using deposition and doping processes. Then, a laser etching process is used to pattern the first doped semiconductor layer by means of a laser spot following a planned path. Based on this, it is understood that in order to completely remove the portion of the first doped semiconductor layer to be removed from the first surface, the position of the laser spot irradiated in the current irradiation along the first direction overlaps with the position irradiated by the previous laser spot, and the position of the laser spot irradiated in the current row along the second direction also overlaps with the position irradiated by the previous row of laser spots. Since the overlapping positions have undergone at least two high-temperature laser irradiations, they are prone to damage to the semiconductor substrate below that position. Furthermore, the aforementioned first doped semiconductor layer includes a first boundary extending along the first direction and a second boundary extending along the second direction. The first boundary has a plurality of first protruding units undulating towards the second direction and sequentially distributed along the first direction, and the second boundary has a plurality of second protruding units undulating towards the first direction and sequentially distributed along the second direction. In this context, the first and second protruding units are formed during the actual laser etching process, where the extension directions of the corresponding sides of the laser spot's outline boundary line form certain angles with the first and second directions, respectively. This results in a protruding morphology (e.g., a relatively small serrated or wavy shape) associated with the laser spot at the boundary of the patterned first doped semiconductor layer. It can be seen that the width of a single first protruding unit in the first boundary of the first doped semiconductor layer can, to some extent, reflect the length along the first direction in the laser spot's outline boundary; similarly, the width of a single second protruding unit in the second boundary of the first doped semiconductor layer can, to some extent, reflect the length along the second direction in the laser spot's outline boundary. In this case, when the width of the first protruding unit is less than the width of the second protruding unit, the length along the first direction in the laser spot's outline boundary is also less than the length along the second direction, resulting in a roughly rectangular laser spot. Compared with using a square spot with small side lengths to pattern the first doped semiconductor layer, using a rectangular spot with a larger long side length to pattern the first doped semiconductor layer can reduce the number of reciprocating movements of the laser spot along the second direction during the patterning process, reduce the damage to the semiconductor substrate caused by high-temperature laser irradiation, and help improve the conversion efficiency of solar cells. At the same time, it can also improve the utilization rate of laser energy and the production capacity of patterning, thereby improving the manufacturing efficiency of solar cells.

[0007] As one possible implementation, the first doped semiconductor layer further includes a plurality of first connection regions. The first connection regions are disposed between at least two adjacent first strip regions and are electrically connected to each of the two adjacent first strip regions. The boundary extending along a first direction in each of the first strip regions has a first protruding unit. At least one boundary extending along a second direction in either the first connection region or the first strip region has a second protruding unit. In this case, during the patterning process of the first doped semiconductor layer, the number of reciprocating movements of the laser spot along the second direction in the region located between two adjacent first connection regions along the first direction and / or between two adjacent first strip regions along the first direction on the first surface can be reduced. This reduces damage to the semiconductor substrate caused by high-temperature laser irradiation, which is beneficial for improving the conversion efficiency of the solar cell. Simultaneously, it can also increase the production capacity of the patterning process and improve the manufacturing efficiency of the solar cell.

[0008] As one possible implementation, the solar cell further includes a second doped semiconductor layer. The second doped semiconductor layer has the opposite doping type to the first doped semiconductor layer. The second doped semiconductor layer is disposed on a second surface; or, the second doped semiconductor layer and the first doped semiconductor layer are alternately distributed on a first surface. The extinction coefficient of the first doped semiconductor layer is greater than that of the second doped semiconductor layer.

[0009] When using the above technical solution, since the extinction coefficient of the first doped semiconductor layer is greater than that of the second doped semiconductor layer, the first doped semiconductor layer has a relatively higher density compared to the second doped semiconductor layer. Therefore, patterning the first doped semiconductor layer using laser etching is more difficult. Based on this, when the width of the first protruding unit is smaller than the width of the second protruding unit, a rectangular spot with a smaller short side can be used to pattern the denser first doped semiconductor layer. Since the long side of the rectangular spot is roughly parallel to the second direction, the number of laser repetitions along the second direction is reduced, decreasing laser damage and patterning time, improving productivity and efficiency. The resulting first protruding unit has a width smaller than the second protruding unit. Furthermore, because the first protruding unit is smaller, more laser spots correspond to the first boundary of the first doped semiconductor layer, which helps prevent the presence of residual first doped semiconductor layer outside the first boundary, reducing carrier recombination rate, reducing leakage and parasitic absorption caused by residual first doped semiconductor layer, and improving the conversion efficiency of the solar cell.

[0010] As one possible implementation, when both the second doped semiconductor layer and the first doped semiconductor layer are disposed on the first surface, the second doped semiconductor layer includes a plurality of second strip-shaped regions extending along a first direction and spaced apart along a second direction. The second strip-shaped regions and the first strip-shaped regions are alternately spaced along the second direction. The thickness of the first doped semiconductor layer is greater than the thickness of the second doped semiconductor layer; and / or, along the second direction, the width of the first strip-shaped region is greater than the width of the second strip-shaped region.

[0011] With the above technical solution, a larger thickness of the first doped semiconductor layer can improve its passivation effect on the semiconductor substrate and reduce the difference in passivation between the first and second doped semiconductor layers. Furthermore, when the width of the first strip region included in the first doped semiconductor layer is large, it is beneficial to increase the area ratio of the first doped semiconductor layer on the first surface, thereby reducing the amount of etching required for patterning the highly dense first doped semiconductor layer using laser etching, reducing etching difficulty, and improving etching capacity. Additionally, by controlling the area ratio of the first and second doped semiconductor layers on one side of the first surface, the area ratio of the PN junction region or high / low junction region formed between the first doped semiconductor layer and the semiconductor substrate can be adjusted, achieving effective carrier diversion. This balances the manufacturing capacity of the solar cell with the effective collection of carriers, facilitating cost reduction and efficiency improvement.

[0012] As one possible implementation, when both the second doped semiconductor layer and the first doped semiconductor layer are disposed on the first surface, the second doped semiconductor layer includes a third boundary extending along a first direction and a fourth boundary extending along a second direction. The third boundary has a plurality of third protruding units undulating towards the second direction and sequentially distributed along the first direction, and the fourth boundary has a fourth protruding unit undulating towards the first direction and sequentially distributed along the second direction. Wherein, the width of the first protruding unit is less than the width of the third protruding unit; and / or, the width of the first protruding unit is less than the width of the fourth protruding unit; and / or, the width of the second protruding unit is less than the width of the third protruding unit; and / or, the width of the second protruding unit is less than the width of the fourth protruding unit; and / or, the width of the third protruding unit is equal to the width of the fourth protruding unit.

[0013] As described above, when the above technical solution is adopted, the width of a single protruding unit in the boundary of the doped semiconductor layer can, to a certain extent, reflect the length along the corresponding direction in the laser spot outline boundary. In this case, when the width of the first protruding unit is smaller than the width of the third protruding unit, the size of the laser spot etching the first doped semiconductor layer along the first direction is smaller than the size of the laser spot etching the second doped semiconductor layer along the first direction. This is beneficial for reducing the area of ​​the laser spot etching the first doped semiconductor layer. With the same etching energy, it is beneficial for increasing the etching energy per unit area of ​​the laser spot etching the first doped semiconductor layer. This is beneficial for thoroughly etching the part to be removed in the first doped semiconductor layer, preventing residues, reducing the carrier recombination rate, and also reducing parasitic absorption. Furthermore, when the area of ​​the second doped semiconductor layer on the first surface is relatively small (compared to the area of ​​the first doped semiconductor layer on the first surface), etching the second doped semiconductor layer with a larger laser spot can improve the etching efficiency. At the same time, the density of the second doped semiconductor layer is relatively low. Even if the etching energy per unit area is low due to the larger area of ​​the laser spot used to etch the second doped semiconductor layer, it can still ensure that the second doped semiconductor layer to be removed is completely removed. This can also reduce the thermal damage to the already formed first doped semiconductor layer caused by laser etching, which is beneficial to improving the yield and conversion efficiency of solar cells.

[0014] As for the beneficial effect of the first protruding unit being narrower than the fourth protruding unit, the second protruding unit being narrower than the third protruding unit, and the second protruding unit being narrower than the fourth protruding unit, the application principle can refer to the application principle of the beneficial effect of the first protruding unit being narrower than the third protruding unit as described above, and will not be repeated here.

[0015] In addition, when the width of the third protruding unit is equal to the width of the fourth protruding unit, the laser spot for etching the second doped semiconductor layer is a square-shaped spot. At this time, different sizes and shapes of laser spots can be used to etch the first and second doped semiconductor layers on the first surface, depending on their different distributions, which helps to improve etching efficiency and etching yield.

[0016] As one possible implementation, the second doped semiconductor layer includes a plurality of second strip regions and a plurality of second connection regions. The plurality of second strip regions extend along a first direction and are spaced apart along a second direction. The second strip regions and the first strip regions are alternately spaced along the second direction. At least one second connection region is disposed between two adjacent second strip regions and is electrically connected to each of the two adjacent second strip regions. The boundary of each second strip region extending along the first direction has a third protruding unit. At least one of the second connection regions and the second strip region has a fourth protruding unit at its boundary extending along the second direction.

[0017] When the above technical solution is adopted, during the patterning process of the second doped semiconductor layer, a large laser spot can be used to etch the area between two adjacent second connection regions along the first direction and / or between two adjacent second strip regions along the first direction on the first surface. This improves the etching efficiency while preventing thermal damage to the first doped semiconductor layer below by laser etching, which is beneficial to improving the yield and conversion efficiency of solar cells.

[0018] As one possible implementation, the first doped semiconductor layer has the opposite doping type to the semiconductor substrate; and / or, the first doped semiconductor layer has the P-type doping type.

[0019] As one possible implementation, in the first surface, the region where the first doped semiconductor layer is disposed is designated as the first region, and the remaining region is designated as the second region. The surface of the second region is provided with an array of textured structures. The textured structures include multiple clustered textured structures spaced apart, with different clustered textured structures in the same row spaced apart along a first direction. Alternatively, the textured structures include fishbone-like textured structures or grid-like textured structures continuously distributed at least along the first direction. In this case, the presence of the textured structures enhances the light-trapping effect of the second region surface, improving the light utilization efficiency of the solar cell. Furthermore, it can increase the passivation contact area between the second region and the surface passivation layer or the second doped semiconductor layer located on it, reducing the carrier recombination rate.

[0020] As one possible implementation, when a clustered texture structure is provided on the surface of the second region, the distance between two clustered texture structures located within two adjacent first strip-shaped regions along the second direction and adjacent to each other along the first direction in the second region is the first distance. The distance between two adjacent clustered texture structures located within two adjacent first strip-shaped regions along the second direction and spaced apart along the second direction in the second region is the second distance, or the distance between the clustered texture structure and the edge of the second region's outline along the second direction is the second distance. The first distance is less than the second distance.

[0021] As described above, in order to completely remove the portion of the first doped semiconductor layer to be removed from the first surface, the laser spot irradiated in the current direction overlaps with the position irradiated by the previous laser spot along the first direction. Simultaneously, the laser spot irradiated in the current row along the second direction also overlaps with the position irradiated by the previous row of laser spots. Since the overlapping positions have undergone at least two high-temperature laser irradiations, a clustered texture structure can be formed on the semiconductor substrate surface below these overlapping positions by adjusting parameters such as etching energy and etching time. Based on this, the spacing of the clustered texture structure along the first direction can reflect the size of the non-overlapping portion of the laser spot along the first direction, and thus the size of the laser spot along the first direction. Similarly, the spacing of the clustered texture structure along the second direction can also reflect the size of the non-overlapping portion of the laser spot along the second direction, and thus the size of the laser spot along the second direction. Furthermore, the spacing between the clustered texture structure and the edge of the second region contour along the second direction can also reflect the size of the laser spot along the second direction. Based on this, when the first spacing is smaller than the second spacing, the length along the first direction in the laser spot outline boundary is also smaller than the length along the second direction. This also indicates that the laser spot used to pattern the first doped semiconductor layer is a rectangular spot, which reduces the number of reciprocating movements of the laser spot along the second direction during the patterning process, reduces the damage to the semiconductor substrate caused by high-temperature laser irradiation, and helps to improve the conversion efficiency of the solar cell. At the same time, it can also improve the utilization rate of laser energy and the production capacity of patterning, thereby improving the manufacturing efficiency of the solar cell.

[0022] As one possible implementation, when a clustered texture structure is formed on the surface of the second region, the spacing between two adjacent clustered texture structures along the first direction is smaller than the minimum spacing between the outermost clustered texture structure along the first direction and the edge of the second region's contour. In this case, thermal damage to the semiconductor substrate at the edge of the second region's contour caused by high-temperature laser is reduced, thus lowering the risk of leakage.

[0023] As one possible implementation, when a clustered texture structure is formed on the surface of the second region, the maximum size of at least one clustered texture structure along the first direction is greater than its maximum size along the second direction. In this case, the overlap rate of the laser spot along the first direction is greater than the overlap rate of the laser spot along the second direction. The greater overlap rate along the first direction is beneficial for reducing the etching length of the laser spot along the first direction while keeping the spot size fixed. This is advantageous for increasing the area ratio of the first doped semiconductor layer on the first surface, increasing the carrier collection area, and reducing the contact resistance.

[0024] As one possible implementation, at least a portion of the surface of the second region is provided with an array of texture structures. The surface of the second region is also provided with a base-like texture structure. The one-dimensional dimension of the base-like texture structure is larger than the one-dimensional dimension of at least one texture structure. Specifically, the one-dimensional dimension of the texture structure is the one-dimensional dimension of the clustered texture structure, or the one-dimensional dimension of the texture structure is the width of a single texture strip in a fishbone-like texture structure or a mesh-like texture structure.

[0025] With the above technical solution, the texture structure is distributed on the second region, which also has a tower-like texture structure, which helps to improve the light trapping effect on the surface of the second region. In addition, the one-dimensional size of the texture structure is smaller than that of the tower-like texture structure, which makes the area of ​​thermal damage to the semiconductor substrate caused by laser etching smaller, thus helping to reduce the carrier recombination rate.

[0026] As one possible implementation, if a clustered texture structure is provided on the surface of the second region, the clustered texture structure includes multiple pore structures. In this case, it is beneficial to increase the specific surface area of ​​the clustered texture structure and enhance the light-trapping effect.

[0027] As one possible implementation, where both the second doped semiconductor layer and the first doped semiconductor layer are disposed on the first surface, the second region includes a first sub-region and a second sub-region. The second doped semiconductor portion is disposed on the first sub-region. The second sub-region is located between the first sub-region and the first region, serving to separate the first doped semiconductor layer and the second doped semiconductor layer. A textured structure is distributed on the surface of the first sub-region; and / or, the surface of the second sub-region is textured.

[0028] With the above technical solution, the surface of the second sub-region is textured, which can improve the bifaciality of the solar cell. Furthermore, texturing the second sub-region allows for further etching of the second sub-region located between the second and first doped semiconductor layers, eliminating any residue of the second and first doped semiconductor layers at this location and reducing the risk of leakage.

[0029] In a second aspect, the present invention provides a method for manufacturing a solar cell, the method comprising: first, providing a semiconductor substrate; the semiconductor substrate including a first surface and a second surface opposite to each other. Next, forming a first doped semiconductor layer integrally disposed on the first surface. Next, employing a laser etching process and patterning the first doped semiconductor layer using a rectangular laser spot, such that the remaining first doped semiconductor layer is located on a local region of the first surface. The first doped semiconductor layer includes a plurality of first strip-shaped regions extending along a first direction and spaced apart along a second direction. The first direction is different from the second direction. The short side of the rectangular laser spot is substantially parallel to the first direction, and the long side of the rectangular laser spot is substantially parallel to the second direction. The first doped semiconductor layer includes a first boundary extending along the first direction and a second boundary extending along the second direction. The first boundary has a plurality of first protruding units undulating towards the second direction and sequentially distributed along the first direction, and the second boundary has a plurality of second protruding units undulating towards the first direction and sequentially distributed along the second direction. The width of the first protruding unit is greater than the width of the second protruding unit.

[0030] As one possible implementation, the overlap rate of the rectangular light spots along the first direction is greater than the overlap rate of the rectangular light spots along the second direction.

[0031] As one possible implementation, after patterning the first doped semiconductor layer using a laser etching process and a rectangular laser spot, the method for manufacturing a solar cell further includes: forming a second doped semiconductor layer integrally disposed on the first surface. The second doped semiconductor layer has the opposite doping type to the first doped semiconductor layer, and the extinction coefficient of the first doped semiconductor layer is greater than that of the second doped semiconductor layer. Next, a laser etching process is used to pattern the second doped semiconductor layer using a square laser spot, so that the remaining second doped semiconductor layer is located in a local area of ​​the first surface, and the first and second doped semiconductor layers are alternately distributed.

[0032] As one possible implementation, the length of the long side of the rectangular light spot is less than the side length of the square light spot; and / or, the length of the short side of the rectangular light spot is less than the side length of the square light spot; and / or, the illumination area of ​​a single rectangular light spot is less than the illumination area of ​​a single square light spot; and / or, along the second direction, the overlap rate of the rectangular light spots is less than the overlap rate of the square light spots.

[0033] The beneficial effects of the second aspect and its various implementations in this invention can be found in the analysis of the beneficial effects of the first aspect and its various implementations, and will not be repeated here.

[0034] Thirdly, the present invention provides a photovoltaic module comprising: a cell string and an encapsulation layer. The cell string is formed by electrically connecting multiple solar cells as provided in the first aspect and its various implementations; the encapsulation layer covers the surface of the cell string.

[0035] The beneficial effects of the third aspect and its various implementations in this invention can be found in the analysis of the beneficial effects of the first aspect and its various implementations, and will not be repeated here. Attached Figure Description

[0036] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this invention, illustrate exemplary embodiments of the invention and are used to explain the invention, but do not constitute an undue limitation of the invention. In the drawings:

[0037] Figure 1 This is a longitudinal cross-sectional view of a first structure of a solar cell provided in an embodiment of the present invention;

[0038] Figure 2 This is a schematic diagram showing the distribution of the first doped semiconductor layer on the first surface of the solar cell provided in an embodiment of the present invention. Figure 1 ;

[0039] Figure 3 This is a schematic diagram showing the distribution of the first doped semiconductor layer on the first surface of the solar cell provided in an embodiment of the present invention. Figure 2 ;

[0040] Figure 4 This is a schematic diagram showing the distribution of the first doped semiconductor layer on the first surface of the solar cell provided in an embodiment of the present invention. Figure 3 ;

[0041] Figure 5 This is a SEM image of a portion of the first boundary of the first doped semiconductor layer in a solar cell provided in an embodiment of the present invention.

[0042] Figure 6 This is a SEM image of a portion of the second boundary of the first doped semiconductor layer in a solar cell provided in an embodiment of the present invention.

[0043] Figure 7 A schematic diagram of the laser spot etching scheme during the manufacturing process of a solar cell provided in an embodiment of the present invention;

[0044] Figure 8 This is a longitudinal cross-sectional view of a second structure of a solar cell provided in an embodiment of the present invention;

[0045] Figure 9 This is a longitudinal cross-sectional schematic diagram of a third structure of a solar cell provided in an embodiment of the present invention;

[0046] Figure 10 This is a longitudinal cross-sectional view of a fourth structure of a solar cell provided in an embodiment of the present invention;

[0047] Figure 11 A longitudinal cross-sectional view of the fifth structure of a solar cell provided in an embodiment of the present invention;

[0048] Figure 12 A longitudinal cross-sectional view of a sixth structure of a solar cell provided in an embodiment of the present invention;

[0049] Figure 13 This is a schematic diagram showing the distribution of the first doped semiconductor layer and the second doped semiconductor layer on the first surface of the solar cell provided in an embodiment of the present invention. Figure 1 ;

[0050] Figure 14 This is a schematic diagram showing the distribution of the first doped semiconductor layer and the second doped semiconductor layer on the first surface of the solar cell provided in an embodiment of the present invention. Figure 2 ;

[0051] Figure 15 This is a schematic diagram showing the distribution of the first doped semiconductor layer and the second doped semiconductor layer on the first surface of the solar cell provided in an embodiment of the present invention. Figure 3 ;

[0052] Figure 16 This is a SEM image of the structure of a portion of the second region in a solar cell provided in an embodiment of the present invention;

[0053] Figure 17 This is a SEM image of the structure of a solar cell at a portion of the cluster-like texture structure provided in an embodiment of the present invention;

[0054] Figure 18 This is a schematic diagram of the structure of a solar cell with a partial grid-like texture structure provided in an embodiment of the present invention.

[0055] Reference numerals: 11 is a semiconductor substrate, 12 is a first doped semiconductor layer, 13 is a first strip region, 14 is a first boundary, 15 is a second boundary, 16 is a first protruding unit, 17 is a second protruding unit, 18 is a first connection region, 19 is a second doped semiconductor layer, 20 is a second strip region, 21 is a third boundary, 22 is a fourth boundary, 23 is a third protruding unit, 24 is a fourth protruding unit, 25 is a second connection region, 26 is a first region, 27 is a second region, 28 is a clustered texture structure, 29 is a first sub-region, 30 is a second sub-region, 31 is an interface passivation layer, 32 is a laser spot, and 33 is a mesh-like texture structure. Detailed Implementation

[0056] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. However, it should be understood that these descriptions are merely exemplary and not intended to limit the scope of the invention. Furthermore, descriptions of well-known structures and techniques are omitted in the following description to avoid unnecessarily obscuring the concept of the invention.

[0057] The accompanying drawings illustrate various structural schematic diagrams according to embodiments of the present invention. These drawings are not to scale, and some details have been enlarged for clarity, and some details may have been omitted. The shapes of the various regions and layers shown in the drawings, as well as their relative sizes and positional relationships, are merely exemplary and may deviate from reality due to manufacturing tolerances or technical limitations. Furthermore, those skilled in the art can design regions / layers with different shapes, sizes, and relative positions as needed.

[0058] In the context of this invention, when a layer / element is referred to as being "on" another layer / element, the layer / element may be directly on the other layer / element, or there may be an intermediate layer / element between them. Furthermore, if a layer / element is "on" another layer / element in one orientation, then when the orientation is reversed, the layer / element may be "below" the other layer / element. To make the technical problems, technical solutions, and beneficial effects of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0059] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified. "Several" means one or more, unless otherwise explicitly specified.

[0060] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0061] Firstly, embodiments of the present invention provide a solar cell. In terms of electrode placement, the solar cell can be a double-sided contact cell or a back-contact cell. In terms of electrode type, the solar cell can be a cell with a main grid or a cell without a main grid. Embodiments of the present invention do not specifically limit the type of solar cell.

[0062] like Figures 1 to 4 As shown, the solar cell includes a semiconductor substrate 11 and a first doped semiconductor layer 12. The semiconductor substrate 11 includes a first surface and a second surface opposite to each other. The first doped semiconductor layer 12 is disposed on a local area of ​​the first surface.

[0063] The first doped semiconductor layer 12 includes a plurality of first strip regions 13 extending along a first direction and spaced apart along a second direction.

[0064] The first direction is different from the second direction.

[0065] like Figures 2 to 6 As shown, the first doped semiconductor layer 12 includes a first boundary 14 extending along a first direction and a second boundary 15 extending along a second direction. The first boundary 14 has a plurality of first protrusion units 16 undulating toward the second direction and sequentially distributed along the first direction, and the second boundary 15 has a plurality of second protrusion units 17 undulating toward the first direction and sequentially distributed along the second direction.

[0066] In the actual manufacturing process, since the first doped semiconductor layer is disposed on a local area of ​​the first surface of the semiconductor substrate, a deposition and doping process can be used to form a first doped semiconductor layer that is entirely disposed on the first surface. Then, a laser etching process is used to pattern the first doped semiconductor layer by means of a laser spot following a planned path. In the boundary of the first doped semiconductor layer, the first and second protruding units are formed during the actual laser etching process by the extension directions of the corresponding sides of the laser spot's outline boundary line having a certain angle with the first and second directions, respectively. This results in a protruding morphology (e.g., a relatively small serrated or wavy shape) associated with the laser spot at the boundary of the first doped semiconductor layer after patterning. It can be seen that in the first boundary of the first doped semiconductor layer, the width of a single first protruding unit can, to some extent, reflect the length along the first direction in the laser spot outline boundary; and in the second boundary of the first doped semiconductor layer, the width of a single second protruding unit can, to some extent, reflect the length along the second direction in the laser spot outline boundary.

[0067] It can be seen that the shape and size of the first protrusion unit and the second protrusion unit can be set according to the shape and size of the laser spot used when etching the first doped semiconductor layer, as well as actual needs.

[0068] like Figure 5 and Figure 6 As shown, the width of the first protruding unit 16 can be smaller than the width of the second protruding unit 17. In this case, it is understood that in order to completely remove the portion of the first doped semiconductor layer 12 to be removed from the first surface, the position of the laser spot 32 irradiated in the current irradiation along the first direction overlaps with the position irradiated by the previous laser spot 32. Simultaneously, the position of the laser spot 32 irradiated in the current row along the second direction also overlaps with the position irradiated by the previous row of laser spots 32. Since the overlapping positions have undergone at least two high-temperature laser irradiations, they are prone to damage to the semiconductor substrate 11 below that position. Therefore, when the width of the first protruding unit 16 is smaller than the width of the second protruding unit 17, the length of the laser spot 32's outline boundary along the first direction is also smaller than the length along the second direction. In this case, the laser spot 32 is a quasi-rectangular spot (e.g., a rectangular spot of 240μm*135μm). Compared with using a square spot with small side lengths (e.g., a square spot of 190μm*190μm) to pattern the first doped semiconductor layer 12, using a rectangular spot with a larger long side length to pattern the first doped semiconductor layer 12 can reduce the number of reciprocating movements of the laser spot 32 along the second direction during the patterning process, reduce the damage to the semiconductor substrate 11 caused by high-temperature laser irradiation, and help improve the conversion efficiency of the solar cell. At the same time, it can also improve the utilization rate of laser energy and the production capacity of patterning, thereby improving the manufacturing efficiency of the solar cell.

[0069] It should be noted that, Figure 7 In the diagram, different dashed line shapes show the approximate shape of different laser spots; the triangular area is the overlapping area of ​​only two adjacent laser spot etching areas; the parallelogram area is the overlapping area of ​​only two adjacent rows of laser spot etching areas; and the circular area is the total overlapping area of ​​the laser spot in two adjacent laser spot etching areas and two adjacent rows of laser spot etching areas.

[0070] In practical applications, the embodiments of the present invention do not specifically limit the correspondence between the first and second surfaces of the semiconductor substrate and the front (directly illuminated surface) and back surfaces of the solar cell, or the formation range of the first doped semiconductor layer on the first surface of the semiconductor substrate. These can be determined according to the type of solar cell and actual needs.

[0071] Among them, such as Figures 8 to 10 As shown, in the case of a double-sided contact solar cell, the first side of the semiconductor substrate 11 can correspond to either the front or back side of the solar cell.

[0072] like Figure 11As shown, in the case of a back-contact solar cell, the first surface of the semiconductor substrate 11 corresponds to the back surface of the solar cell.

[0073] For example, such as Figures 8 to 10 As shown, the solar cell may further include a second doped semiconductor layer 19. The doping type of the second doped semiconductor layer 19 is opposite to that of the first doped semiconductor layer 12. The second doped semiconductor layer 19 is disposed on the second surface; or, both the second doped semiconductor layer 19 and the first doped semiconductor layer 12 are disposed on the first surface. The location of the second doped semiconductor layer 19 on the semiconductor substrate 11 is determined according to the type of cell and actual requirements.

[0074] In the case of a double-sided contact solar cell, such as Figures 8 to 10 As shown, the second doped semiconductor layer 19 is disposed on the second surface. In this case, the boundary of the second doped semiconductor layer 19 can coincide with the boundary of the second surface, that is, the entire second doped semiconductor layer 19 is disposed on the second surface; or, the second surface can also be disposed on a local area of ​​the second surface.

[0075] In the case of a back-contact solar cell, such as Figure 11 As shown, the second doped semiconductor layer 19 and the first doped semiconductor layer 12 can be alternately distributed on the first surface; or, the second doped semiconductor layer can also extend to cover part of the first doped semiconductor layer, in which case the overlapping part of the first doped semiconductor layer and the second doped semiconductor layer can be electrically insulated by an insulating layer (such as a silicon oxide layer, an aluminum oxide layer or a silicon nitride layer); or, in the overlapping area, at least part of the first doped semiconductor layer can also be electrically connected to at least part of the second doped semiconductor layer to reduce the risk of hot spots in the solar cell.

[0076] In terms of doping type, the first doped semiconductor layer can be P-type, in which case the second doped semiconductor layer is N-type; or, the first doped semiconductor layer can also be N-type, in which case the second doped semiconductor layer is P-type. Furthermore, the doping types of the first doped semiconductor layer and the semiconductor substrate can be opposite (e.g., the semiconductor substrate is N-type, and the first doped semiconductor layer is P-type), or they can be the same.

[0077] From a material perspective, the materials of the first doped semiconductor layer and / or the second doped semiconductor layer can include any semiconductor material such as silicon, germanium-silicon, or germanium. The materials of the first and second doped semiconductor layers can be the same or different. For example, both the first and second doped semiconductor layers can be doped crystalline silicon layers (such as at least one of polycrystalline silicon, monocrystalline silicon, nanocrystalline silicon, and microcrystalline silicon). Another example is that the first doped semiconductor layer is a doped crystalline silicon layer, and the second doped semiconductor layer is a doped amorphous silicon layer.

[0078] For example, the extinction coefficient of the first doped semiconductor layer can be greater than that of the second doped semiconductor layer. In this case, because the extinction coefficient of the first doped semiconductor layer is greater than that of the second doped semiconductor layer, the first doped semiconductor layer has a relatively higher density compared to the second doped semiconductor layer, making it more difficult to pattern the first doped semiconductor layer using laser etching. Based on this, a rectangular laser spot can be used to pattern the denser first doped semiconductor layer. Since the long side of the rectangular laser spot is roughly parallel to the second direction, the number of times the laser travels along the second direction is reduced, decreasing laser damage and patterning time, improving power generation and efficiency. The width of the first protrusion unit is smaller than that of the second protrusion unit. Furthermore, because the width of the first protrusion unit is smaller, there are more laser spots at the first boundary of the first doped semiconductor layer, which helps prevent the presence of residual first doped semiconductor layer outside the first boundary, reducing the carrier recombination rate, reducing leakage and parasitic absorption caused by the residual first doped semiconductor layer, and improving the conversion efficiency of the solar cell.

[0079] Alternatively, the extinction coefficient of the first doped semiconductor layer can be equal to the extinction coefficient of the second doped semiconductor layer.

[0080] The specific values ​​of the extinction coefficients of the first doped semiconductor layer and the second doped semiconductor layer can be set according to the materials and doping types of the first and second doped semiconductor layers, as well as actual needs, and are not specifically limited here.

[0081] In addition, such as Figures 8 to 11 As shown, the first doped semiconductor layer 12 and / or the second doped semiconductor layer 19 can be directly disposed on the semiconductor substrate 11. Alternatively, as... Figure 12As shown, the solar cell may further include an interface passivation layer 31; the interface passivation layer 31 is located between the semiconductor substrate 11 and the first doped semiconductor layer 12 and / or the second doped semiconductor layer 19. The material and thickness of the interface passivation layer 31 can be set according to the materials of the first doped semiconductor layer 12 and / or the second doped semiconductor layer 19, and actual needs. For example, when the first doped semiconductor layer and / or the second doped semiconductor layer are doped polycrystalline silicon layers, the interface passivation layer is a tunneling passivation layer. The material of the tunneling passivation layer may include materials such as silicon oxide, aluminum oxide, or titanium oxide. Another example: when the materials of the first doped semiconductor layer and / or the second doped semiconductor layer may include at least one of doped amorphous silicon, doped nanocrystalline silicon, and doped microcrystalline silicon, the interface passivation layer is at least one of intrinsic amorphous silicon, intrinsic nanocrystalline silicon, and intrinsic microcrystalline silicon.

[0082] When an interface passivation layer is provided between the first doped semiconductor layer and the second doped semiconductor layer and the semiconductor substrate, the materials of the two interface passivation layers can be the same or different.

[0083] For example, in the case of a double-sided contact solar cell, the first doped semiconductor layer disposed on the first surface of the semiconductor substrate is a doped polycrystalline silicon layer, and the passivation layer at the interface between the first doped semiconductor layer and the semiconductor substrate is a tunneling passivation layer. The second doped semiconductor layer disposed on the second surface of the semiconductor substrate can also be a doped polycrystalline silicon layer, and the passivation layer at the interface between the second doped semiconductor layer and the semiconductor substrate is a tunneling passivation layer; alternatively, the second doped semiconductor layer can also be a doped amorphous silicon layer, and the passivation layer at the interface between the second doped semiconductor layer and the semiconductor substrate can be an intrinsic amorphous silicon layer.

[0084] For example, in the case of a back-contact solar cell, both the first and second doped semiconductor layers are doped polycrystalline silicon layers. The interface passivation layers disposed between the semiconductor substrate and the first and second doped semiconductor layers are both tunneling passivation layers.

[0085] In terms of thickness, the specific thicknesses of the first doped semiconductor layer and the second doped semiconductor layer can be set according to the doping type and concentration of the two layers, as well as actual needs, and are not specifically limited here.

[0086] For example, the thickness of the first doped semiconductor layer can be greater than the thickness of the second doped semiconductor layer. In this case, a larger thickness of the first doped semiconductor layer can improve its passivation effect on the semiconductor substrate and reduce the difference in passivation effect between the first and second doped semiconductor layers. For instance, if the doping concentration of the P-type doped semiconductor layer is less than that of the N-type doped semiconductor layer, then setting a larger thickness for the P-type doped semiconductor layer is beneficial for enhancing its passivation effect.

[0087] Alternatively, the thickness of the first doped semiconductor layer can be equal to the thickness of the second doped semiconductor layer.

[0088] In terms of appearance, such as Figures 2 to 4 As shown, the first doped semiconductor layer 12 may include a plurality of first strip regions 13 extending along a first direction and spaced apart along a second direction. The first direction is different from the second direction.

[0089] The first direction and the second direction can be any two different directions parallel to the first surface. The specific directions referred to by the first direction and the second direction can be set according to the shape of the first surface and actual needs, and are not specifically limited here. For example: the first direction and the second direction are perpendicular; the shape of the first surface is a rectangle, and the first direction and the second direction are parallel to the extension direction of the long side and the extension direction of the short side of the rectangle, respectively.

[0090] The number and size of the first strip regions included in the first doped semiconductor layer, as well as the spacing between adjacent first strip regions, can be set according to the doping type and extinction coefficient of the first doped semiconductor layer, and actual needs, and are not specifically limited here.

[0091] In addition, such as Figure 2 As shown, when the first doped semiconductor layer 12 includes only the first strip region 13, the first boundary 14 of the first doped semiconductor layer 12 has a first protrusion unit 16 located in the boundary of the first strip region 13 extending along the first direction, and the second boundary 15 of the first doped semiconductor layer 12 has a second protrusion unit 17 located in the boundary of the first strip region 13 extending along the second direction.

[0092] Or, for example, such as Figure 3 and Figure 4As shown, the first doped semiconductor layer 12 may further include a plurality of first connection regions 18. Each first connection region 18 is disposed between at least two adjacent first strip regions 13 and is electrically connected to each of the two adjacent first strip regions 13. The first connection regions 18 may be located only between two adjacent first strip regions 13, or at least one first connection region 18 may be located outside the first strip region 13 along the second direction. Alternatively, each pair of adjacent first strip regions may have a first connection region 18, or some pairs of adjacent first strip regions may not have a first connection region 18. The morphology and distribution of the first connection regions 18 can be determined based on the morphology of the electrode structure electrically connected to the first doped semiconductor layer 12, and are not specifically limited here.

[0093] When the first doped semiconductor layer includes a first strip region and a first connection region, the boundary of the first strip region extending along the first direction has a first protruding unit. As for the distribution of the second protruding units, they can be located only on the boundary of the first connection region extending along the second direction; they can also be located only on the boundary of the first strip region extending along the second direction; or they can both the boundary of the first connection region and the boundary of the first strip region extending along the second direction have second protruding units. Specifically, the distribution of the second protruding units can be determined based on the size of the laser spot used to etch the first doped semiconductor layer and the length of the boundaries of the first connection region and the first strip region extending along the second direction. For example, when the length of the boundary of the first connection region and / or the first strip region extending along the second direction is greater than the size of the laser spot along the second direction, the boundary of the first connection region and / or the boundary of the first strip region extending along the second direction has a second protruding unit. In this case, during the patterning process of the first doped semiconductor layer, the number of times the laser spot reciprocates along the second direction in the region between two adjacent first connection regions along the first direction and / or between two adjacent first strip regions along the first direction can be reduced. This reduces the damage to the semiconductor substrate caused by high-temperature laser irradiation, which is beneficial to improving the conversion efficiency of the solar cell. At the same time, it can also increase the production capacity of the patterning process and improve the manufacturing efficiency of the solar cell.

[0094] Regarding the morphology of the second doped semiconductor layer, when the second doped semiconductor layer is only disposed on a local area of ​​the corresponding surface of the semiconductor substrate, such as... Figures 13 to 15 As shown, the second doped semiconductor layer 19 may include a plurality of second strip regions 20 extending along a first direction and spaced apart along a second direction.

[0095] Among them, such as Figures 13 to 15 As shown, when both the second doped semiconductor layer 19 and the first doped semiconductor layer 12 are disposed on the first surface, the second strip region 20 and the first strip region 13 are alternately distributed along the second direction.

[0096] When the second doped semiconductor layer is disposed on the second surface, the orthographic projection of the second strip-shaped region included in the second doped semiconductor layer on the first surface may be located within the orthographic projection of the first strip-shaped region included in the first doped semiconductor layer on the first surface, or may cover the orthographic projection of the first strip-shaped region included in the first doped semiconductor layer on the first surface. Alternatively, the orthographic projection of the second strip-shaped region included in the second doped semiconductor layer on the first surface may be at least partially staggered with the orthographic projection of the first strip-shaped region included in the first doped semiconductor layer on the first surface.

[0097] As for the number and size of the second strip regions included in the second doped semiconductor layer, as well as the spacing between adjacent second strip regions, they can be set according to the doping type and extinction coefficient of the second doped semiconductor layer, the distribution of the second doped semiconductor layer and the first doped semiconductor layer, and actual needs, and are not specifically limited here.

[0098] For example: Figure 12 As shown, when both the second doped semiconductor layer 19 and the first doped semiconductor layer 12 are disposed on the first surface, and the extinction coefficient of the first doped semiconductor layer 12 is greater than that of the second doped semiconductor layer 19, the width of the first strip region 13 along the second direction can be greater than the width of the second strip region 20. In this case, it is beneficial to increase the area ratio of the first doped semiconductor layer 12 on the first surface, thereby reducing the etching amount required for patterning the highly dense first doped semiconductor layer 12 using laser etching, reducing etching difficulty, and improving etching capacity. In addition, by controlling the area ratio of the first doped semiconductor layer 12 and the second doped semiconductor layer 19 on one side of the first surface, the area ratio of the PN junction region or the high-low junction region formed between the first doped semiconductor layer 12 and the semiconductor substrate 11 can be adjusted, achieving effective shunting of charge carriers, so that the manufacturing capacity of the solar cell and the effective collection of charge carriers are balanced, which is beneficial for cost reduction and efficiency improvement.

[0099] Alternatively, if both the second doped semiconductor layer and the first doped semiconductor layer are disposed on the first surface, and the extinction coefficient of the first doped semiconductor layer is greater than the extinction coefficient of the second doped semiconductor layer, the width of the first strip region can also be equal to the width of the second strip region.

[0100] It should be noted that, because the boundary of the first strip-shaped region is provided with a first protruding unit, the boundary of the first strip-shaped region along the first direction has an uneven undulating shape. The width of the first strip-shaped region can be calculated by taking the average of the widths of the portions corresponding to different first protruding units within the first strip-shaped region, or it can be the width of the portions corresponding to different first protruding units within the first strip-shaped region along the middle of the first direction. If the boundary of the second strip-shaped region extending along the first direction also has an undulating shape, its width can be determined by referring to the method for determining the width of the first strip-shaped region, and will not be elaborated here.

[0101] Alternatively, the second doped semiconductor layer may consist only of the second strip-shaped region. Or, as... Figure 14 and Figure 15 As shown, the second doped semiconductor layer 19 may further include a plurality of second connection regions 25. The second connection regions 25 are disposed between at least two adjacent second strip regions 20 and are electrically connected to the two adjacent second strip regions 20 respectively.

[0102] The second connection region may be located only between two adjacent second strip regions, or at least one second connection region may be located outside the second strip region located outward along the second direction. Alternatively, a second connection region may be present between every two adjacent second strip regions, or some adjacent second strip regions may not have a second connection region. The morphology and distribution of the second connection region can be determined based on the morphology of the electrode structure electrically connected to the second doped semiconductor layer, and are not specifically limited here. Furthermore, when both the first and second doped semiconductor layers are disposed on the first surface, and the first doped semiconductor layer also includes a first connection region, the first and second connection regions may be distributed at intervals along the first direction.

[0103] When the second doped semiconductor layer is only disposed on a local area of ​​the corresponding surface of the semiconductor substrate, such as Figures 13 to 15 As shown, the second doped semiconductor layer can be defined as including a third boundary 21 extending along a first direction and a fourth boundary 22 extending along a second direction. The third boundary 21 has a plurality of third protrusion units 23 undulating toward the second direction and sequentially distributed along the first direction, and the fourth boundary 22 has fourth protrusion units 24 undulating toward the first direction and sequentially distributed along the second direction.

[0104] Wherein, when the second doped semiconductor layer includes only the second strip region, the third protrusion unit of the third boundary of the second doped semiconductor layer is located in the boundary of the second strip region extending along the first direction, and the fourth protrusion unit of the fourth boundary of the second doped semiconductor layer is located in the boundary of the second strip region extending along the second direction.

[0105] When the second doped semiconductor layer includes a second strip region and a second connection region, the boundary of the second strip region extending along the first direction has a third protruding unit. As for the distribution location of the fourth protruding unit, it can be that only the boundary of the second connection region extending along the second direction has a fourth protruding unit; it can also be that only the boundary of the second strip region extending along the second direction has a fourth protruding unit; or it can be that both the boundaries of the second connection region and the second strip region extending along the second direction have fourth protruding units. Specifically, the distribution location of the fourth protruding unit can be determined based on the size of the laser spot used to etch the second doped semiconductor layer and the lengths of the boundaries of the second connection region and the second strip region extending along the second direction. For example, when the length of the boundary of the second connection region and / or the second strip region extending along the second direction is greater than the size of the laser spot along the second direction, the boundary of the second connection region and / or the second strip region extending along the second direction has a fourth protruding unit.

[0106] Furthermore, as mentioned earlier, the width of a single protruding unit in the boundary of the doped semiconductor layer can, to some extent, reflect the length along the corresponding direction in the laser spot outline boundary. In the above case, the width and morphology of the third and fourth protruding units can be determined based on the size of the laser spot used to etch the second doped semiconductor layer, and the size relationship between the first and second protruding units in the first doped semiconductor layer and the third and fourth protruding units in the second doped semiconductor layer can be determined based on the distribution of the first and second doped semiconductor layers. No specific limitations are made here.

[0107] For example, the width of the third protruding unit can be equal to the width of the fourth protruding unit. In this case, the laser spot for etching the second doped semiconductor layer is a square-shaped spot (such as a 300μm*300μm square spot, or a 240μm*240μm square spot, etc.). At this time, depending on the different distributions of the first doped semiconductor layer and the second doped semiconductor layer on the corresponding surfaces, laser spots of different sizes and shapes can be used to etch them, which is beneficial to improving etching efficiency and etching yield.

[0108] Of course, a rectangular light spot can also be used to etch the second doped semiconductor layer, in which case the width of the third protrusion unit is different from the width of the fourth protrusion unit.

[0109] For example, when both the second doped semiconductor layer and the first doped semiconductor layer are disposed on the first surface, the width of the first protruding unit can be smaller than the width of the third protruding unit; and / or, the width of the first protruding unit can be smaller than the width of the fourth protruding unit; and / or, the width of the second protruding unit is smaller than the width of the third protruding unit; and / or, the width of the second protruding unit is smaller than the width of the fourth protruding unit. In the above cases, when the width of the first protruding unit is smaller than the width of the third protruding unit, the size of the laser spot etching the first doped semiconductor layer along the first direction is smaller than the size of the laser spot etching the second doped semiconductor layer along the first direction. This is beneficial for reducing the area of ​​the laser spot etching the first doped semiconductor layer. With the same etching energy, this is beneficial for increasing the etching energy per unit area of ​​the laser spot etching the first doped semiconductor layer. This is beneficial for thoroughly etching the portion to be removed from the first doped semiconductor layer, preventing residues, reducing the carrier recombination rate, and also reducing parasitic absorption. Furthermore, when the area of ​​the second doped semiconductor layer on the first surface is relatively small (compared to the area of ​​the first doped semiconductor layer on the first surface), etching the second doped semiconductor layer with a larger laser spot can improve the etching efficiency. At the same time, the density of the second doped semiconductor layer is relatively low. Even if the etching energy per unit area is low due to the larger area of ​​the laser spot used to etch the second doped semiconductor layer, it can still ensure that the second doped semiconductor layer to be removed is completely removed. This can also reduce the thermal damage to the already formed first doped semiconductor layer caused by laser etching, which is beneficial to improving the yield and conversion efficiency of solar cells.

[0110] As for the beneficial effect of the first protruding unit being narrower than the fourth protruding unit, the second protruding unit being narrower than the third protruding unit, and the second protruding unit being narrower than the fourth protruding unit, the application principle can refer to the application principle of the beneficial effect of the first protruding unit being narrower than the third protruding unit as described above, and will not be repeated here.

[0111] When both the second doped semiconductor layer and the first doped semiconductor layer are disposed on the first surface, the difference between the width of the first protruding unit and the width of the third protruding unit and the fourth protruding unit, and the difference between the width of the second protruding unit and the width of the third protruding unit and the fourth protruding unit, can be determined based on the size of the laser spot for etching the first doped semiconductor layer and the second doped semiconductor layer, respectively, and no specific limitation is made here.

[0112] In practical applications, the surface region with the first doped semiconductor layer is defined as the first region, and the remaining region is defined as the second region. In some cases, such as... Figures 16 to 18As shown, the surface of the second region 27 can be provided with an array of textured structures. As mentioned earlier, in order to completely remove the portion of the first doped semiconductor layer that needs to be removed from the first surface, the position of the laser spot irradiated in the current irradiation along the first direction overlaps with the position of the laser spot irradiated in the previous irradiation. At the same time, the position of the laser spot irradiated in the current row along the second direction also overlaps with the position of the laser spot irradiated in the previous row. Since the overlapping position has undergone at least two high-temperature laser irradiations, a textured structure can be formed on the semiconductor substrate surface below the overlapping position by adjusting parameters such as etching energy and etching time. Based on this, the morphology, size, and distribution of the textured structure can be determined according to the size, overlap rate, and energy of the laser spot irradiating the first doped semiconductor layer, and are not specifically limited here.

[0113] Optional, such as Figure 16 and Figure 17 As shown, the texture structure may include multiple clustered texture structures 28 spaced apart, with different clustered texture structures 28 spaced apart along a first direction in the same row. Alternatively, as... Figure 18 As shown, the texture structure may also include at least a fishbone-like texture structure or a mesh-like texture structure 33 continuously distributed along the first direction. In this case, the presence of the texture structure helps to enhance the light-trapping effect of the surface of the second region 27 and improve the light utilization efficiency of the solar cell. In addition, it can also increase the passivation contact area between the second region 27 and the surface passivation layer or the second doped semiconductor layer 19 located on itself, thereby reducing the carrier recombination rate.

[0114] For example, such as Figure 18 As shown, the fishbone-like texture structure or mesh-like texture structure 33 includes individual texture strips that may comprise a linear continuous texture structure composed of multiple small bases. The one-dimensional dimension of a single small base is a few micrometers, such as 2μm to 9μm, and the one-dimensional dimension includes the side length, depth, etc. of the small base.

[0115] For example, such as Figure 16 and Figure 17 As shown, the clustered texture structure 28 may include multiple pore structures. Adjacent pore structures may be spaced apart or adjacent to each other. In this case, it is beneficial to increase the specific surface area of ​​the clustered texture structure 28 and enhance the light-trapping effect. The one-dimensional size of a single pore structure can be several micrometers, such as 2μm to 9μm.

[0116] For example, when a clustered texture structure is provided on the surface of the second region, the maximum size of at least one clustered texture structure along the first direction can be greater than its maximum size along the second direction. In this case, the overlap rate of the laser spot along the first direction is greater than the overlap rate of the laser spot along the second direction. The greater overlap rate along the first direction is beneficial for reducing the etching length of the laser spot along the first direction when the spot size is fixed. This is beneficial for increasing the area ratio of the first doped semiconductor layer on the first surface, increasing the carrier collection area, and reducing the contact resistance.

[0117] The method for determining the maximum size of the clustered texture structure along the first direction can be as follows: first, determine the approximate outer boundary of the clustered texture structure based on its morphology (e.g., when the clustered texture structure includes multiple pore structures, obtain the outer boundary of the clustered texture structure based on the line connecting the boundaries of the outermost pore structures; for example, the maximum size of the clustered texture structure along the first direction is tens of micrometers, which can be around 30 μm). The maximum straight-line distance between the two points with the largest spacing along the first direction within this outer boundary is the maximum size of the clustered texture structure along the first direction. The method for determining the maximum size of the clustered texture structure along the second direction can be referred to the previous text and will not be repeated here.

[0118] Furthermore, within the second region, the spacing between two clustered texture structures located within two adjacent first strip-shaped regions along the second direction and adjacent to each other along the first direction is defined as the first spacing. Also, within the second region, the spacing between two adjacent clustered texture structures located within two adjacent first strip-shaped regions along the second direction and spaced apart along the second direction is defined as the second spacing, or the spacing between the clustered texture structure and the edge of the second region's outline along the second direction is defined as the second spacing. In the above cases, for example, the first spacing can be smaller than the second spacing. In this case, it is understood that the spacing of the clustered texture structures along the first direction can reflect the size of the non-overlapping portion of the laser spot along the first direction, and thus can reflect the size of the laser spot along the first direction. Similarly, the spacing of the clustered texture structures along the second direction can also reflect the size of the non-overlapping portion of the laser spot along the second direction, and thus can reflect the size of the laser spot along the second direction. The spacing between the clustered texture structure and the edge of the second region's outline along the second direction can also reflect the size of the laser spot along the second direction. Based on this, when the first spacing is smaller than the second spacing, the length along the first direction in the laser spot outline boundary is also smaller than the length along the second direction. This also indicates that the laser spot used to pattern the first doped semiconductor layer is a rectangular spot, which reduces the number of reciprocating movements of the laser spot along the second direction during the patterning process, reduces the damage to the semiconductor substrate caused by high-temperature laser irradiation, and helps to improve the conversion efficiency of the solar cell. At the same time, it can also improve the utilization rate of laser energy and the production capacity of patterning, thereby improving the manufacturing efficiency of the solar cell.

[0119] The method for determining the first spacing can be to first determine the approximate outer boundary of the clustered texture structure based on the morphology of the clustered texture structure (for example, when the clustered texture structure includes multiple pore structures, the outer boundary of the clustered texture structure can be obtained by connecting the boundaries of the outermost pore structures). Then, determine the two points with the smallest spacing along the first direction among the outer boundaries of two adjacent clustered texture structures along the first direction, and the spacing between the two points along the first direction is the first spacing.

[0120] As for the second spacing, when the second spacing is the spacing between two adjacent clustered texture structures located between two adjacent first strip regions along the second direction and distributed at intervals along the second direction, the spacing between the two points with the smallest spacing along the second direction at the outer boundaries of the two adjacent clustered texture structures along the second direction is the second spacing in the second direction.

[0121] When the second spacing is the spacing between the clustered texture structure and the edge of the second region contour along the second direction, the spacing between the point closest to the edge of the second region contour along the second direction in the outer boundary of the clustered texture structure and the edge of the second region contour (when the first doped semiconductor layer includes multiple first strip regions, the edge of the second region contour is the boundary of the first strip region) is the second spacing.

[0122] For example, the spacing between two adjacent clustered texture structures along the first direction can be less than the minimum spacing between the outermost clustered texture structure along the first direction and the edge of the second region's contour. The minimum spacing between the outermost clustered texture structure along the first direction and the edge of the second region's contour can be determined based on the distance between the point on the outer boundary of the outermost clustered texture structure along the first direction that is closest to the edge of the second region's contour and the edge of the second region's contour. In this case, thermal damage to the semiconductor substrate at the edge of the second region's contour caused by high-temperature laser is reduced, thus lowering the risk of leakage.

[0123] As for the surface morphology of the second region in the first surface where no first doped semiconductor layer is provided, it can be set according to the type of solar cell, the type of film layer on the second region, and actual needs, and no specific limitation is made here.

[0124] For example, if at least a portion of the surface of the second region has an array of textured structures, a tower-like textured structure may also be provided on the surface of the second region. In this case, it is beneficial to improve the light-trapping effect of the second region.

[0125] In some cases, the one-dimensional dimension of the aforementioned tower-like texture structure can be larger than the one-dimensional dimension of at least one texture structure. Specifically, the one-dimensional dimension of the texture structure is the same as that of the clustered texture structure, or the width W of a single texture strip in a fishbone-like or mesh-like texture structure. In this case, the area of ​​thermal damage to the semiconductor substrate caused by laser etching is smaller, which is beneficial for reducing the carrier recombination rate.

[0126] Among them, such as Figure 12 As shown, when both the second doped semiconductor layer 19 and the first doped semiconductor layer 12 are disposed on the first surface, the second region 27 is defined as including a first sub-region 29 and a second sub-region 30. The second doped semiconductor portion is disposed on the first sub-region 29. The second sub-region 30 is located between the first sub-region 29 and the first region 26, and is used to separate the first doped semiconductor layer 12 and the second doped semiconductor layer 19. This arrangement can reduce the risk of leakage between the first doped semiconductor layer 12 and the second doped semiconductor layer 19.

[0127] The texture structure can be distributed only on the surface of the first sub-region. Alternatively, the texture structure can be distributed on the surfaces of both the first and second sub-regions.

[0128] Furthermore, the surface of the second sub-region can be textured. This configuration can improve the bifaciality of the solar cell. Moreover, texturing the second sub-region allows for further etching of the second sub-region located between the second and first doped semiconductor layers, eliminating any residue of the second and first doped semiconductor layers and reducing the risk of leakage.

[0129] Of course, the surface of the second sub-region can also be planar. Depending on the degree to which the second sub-region is etched, it may retain an array-distributed texture structure, or it may only retain an array-distributed texture structure on the surface of the first sub-region. Similarly, it is even possible to retain an array-distributed texture structure on the surface of the first region.

[0130] Secondly, embodiments of the present invention provide a method for manufacturing a solar cell. The method includes the following steps: First, a semiconductor substrate is provided; the semiconductor substrate includes a first surface and a second surface opposite to each other. Next, a first doped semiconductor layer is formed integrally on the first surface. Next, a laser etching process is used to pattern the first doped semiconductor layer using a rectangular laser spot, so that the remaining first doped semiconductor layer is located on a local area of ​​the first surface. The first doped semiconductor layer includes a plurality of first strip-shaped regions extending along a first direction and spaced apart along a second direction. The first direction is different from the second direction. The short side of the rectangular laser spot is substantially parallel to the first direction, and the long side of the rectangular laser spot is substantially parallel to the second direction. The first doped semiconductor layer includes a first boundary extending along the first direction and a second boundary extending along the second direction. The first boundary has a plurality of first protruding units undulating towards the second direction and sequentially distributed along the first direction, and the second boundary has a plurality of second protruding units undulating towards the first direction and sequentially distributed along the second direction. The width of the first protruding unit is greater than the width of the second protruding unit.

[0131] It should be noted that the structure and materials of the solar cells manufactured using the manufacturing method provided in the embodiments of the present invention can be referred to the description of the structure and materials of the solar cells provided in the first aspect above, and will not be repeated here.

[0132] In the actual manufacturing process, chemical vapor deposition and doping processes can be used to first form a first doped semiconductor layer integrally formed on the first surface, and a mask layer (such as a borosilicate glass layer) formed on the side of the first doped semiconductor layer facing away from the semiconductor substrate. Then, a laser etching process is used to pattern the mask layer and the first doped semiconductor layer sequentially using a rectangular laser spot. The short side of the rectangular laser spot is approximately parallel to the length extension direction (i.e., the first direction) of the first strip-shaped region included in the first doped semiconductor layer. Specifically, when the angle between the short side of the rectangular laser spot and the first direction is greater than 0° and less than or equal to 10°, they can be considered approximately parallel. Since the boundary of the first doped semiconductor layer is not perfectly flat, the first direction can be determined based on the external tangent line of the first boundary within the selected viewing window. In this case, when the angle between the short side of the rectangular laser spot and the external tangent line is greater than 0° and less than or equal to 10°, they can be considered approximately parallel.

[0133] In addition, the size of the rectangular spot, as well as the overlap rate of the rectangular spot along the first direction and the overlap rate of the rectangular spot along the second direction, can be determined based on the size of the area removed by the patterning process of the first doped semiconductor layer, and are not specifically limited here.

[0134] For example, the overlap rate of the rectangular light spots along the first direction can be greater than the overlap rate of the rectangular light spots along the second direction. Alternatively, the overlap rate of the rectangular light spots along the first direction can be equal to or less than the overlap rate of the rectangular light spots along the second direction.

[0135] In addition to providing the semiconductor substrate, the method for manufacturing the solar cell further includes forming a second doped semiconductor layer on the semiconductor substrate with a doping type opposite to that of the first doped semiconductor layer. The formation process of the second doped semiconductor layer can be determined based on the specific formation location of the second doped semiconductor layer on the semiconductor substrate.

[0136] When the second doped semiconductor layer in the manufactured solar cell is located on the second surface of the semiconductor substrate, a chemical vapor deposition and doping process can be used to form a continuous second doped semiconductor layer and a mask layer on the second surface. If the second doped semiconductor layer is only located in a local area of ​​the second surface, a process such as laser etching can be used to pattern the second doped semiconductor layer. The size and overlap rate of the laser spot used for laser etching can be determined based on the size of the area removed by the patterning process of the second doped semiconductor layer, and are not specifically limited here.

[0137] When the second doped semiconductor layer in the manufactured solar cell is located on the first surface, a laser etching process can be used. After patterning the first doped semiconductor layer with a rectangular laser spot, deposition and etching processes are then used to form a continuous second doped semiconductor layer on the first surface. The material and extinction coefficient of this second doped semiconductor layer can be referred to the preceding text. Next, a laser etching process can be used to pattern the second doped semiconductor layer so that the remaining second doped semiconductor layer is located in a local area of ​​the first surface. A square laser spot can be used to pattern the second doped semiconductor layer. The extinction coefficient of the second doped semiconductor layer can be smaller than that of the first doped semiconductor layer. On the first surface, the first and second doped semiconductor layers can be alternately distributed.

[0138] When the second doped semiconductor layer is located on the first surface and a square spot is used to pattern the second doped semiconductor layer, the size relationship between the square spot and the rectangular spot, as well as the overlap rate between the square spot and the rectangular spot, can be determined based on the area size to be laser etched when the first doped semiconductor layer and the second doped semiconductor layer are patterned respectively, and the actual requirements. No specific limitations are made here.

[0139] For example, the length of the long side of the rectangular laser spot can be smaller than the side length of the square laser spot. In this case, it is advantageous to reduce the area of ​​the rectangular laser spot used to etch the first doped semiconductor layer. With the same etching energy, it is advantageous to increase the etching energy per unit area of ​​the rectangular laser spot used to etch the first doped semiconductor layer, which helps to cleanly etch the portion to be removed from the first doped semiconductor layer, preventing residues and reducing the carrier recombination rate, while also reducing parasitic absorption. Furthermore, when the area of ​​the second doped semiconductor layer on the first surface is relatively small (compared to the area of ​​the first doped semiconductor layer on the first surface), using a larger square laser spot to etch the second doped semiconductor layer can improve the etching efficiency. Simultaneously, the second doped semiconductor layer has relatively low density; even if the etching energy per unit area is lower due to the larger area of ​​the square laser spot used to etch the second doped semiconductor layer, it can still ensure that the second doped semiconductor layer to be removed is completely removed. This also reduces thermal damage to the formed first doped semiconductor layer caused by laser etching, which is beneficial for improving the yield and conversion efficiency of solar cells.

[0140] For example, the shorter side of a rectangular light spot is shorter than the side length of a square light spot. The application principle of the beneficial effect in this case can refer to the application principle of the beneficial effect described above, where the longer side of a rectangular light spot can be shorter than the side length of a square light spot.

[0141] For example, the illumination area of ​​a single rectangular light spot is smaller than that of a single square light spot. The application principle of the beneficial effect in this case can refer to the application principle of the beneficial effect described above, where the length of the longer side of the rectangular light spot can be smaller than the side length of the square light spot.

[0142] For example, along the second direction, the overlap rate of rectangular light spots is less than that of square light spots. In this case, it is beneficial to improve the utilization rate of laser energy and the productivity of patterning processing when etching the first doped semiconductor layer, thereby improving the manufacturing efficiency of solar cells. The beneficial effects of the second aspect and its various implementations in the embodiments of the present invention can be referred to the analysis of the beneficial effects in the first aspect and its various implementations, and will not be repeated here.

[0143] Thirdly, embodiments of the present invention provide a photovoltaic module, which includes: a battery string and an encapsulation layer. The battery string is formed by electrically connecting multiple solar cells as provided in the first aspect and its various implementations; the encapsulation layer covers the surface of the battery string.

[0144] The beneficial effects of the third aspect and its various implementations in the embodiments of the present invention can be referred to the analysis of the beneficial effects of the first aspect and its various implementations, and will not be repeated here.

[0145] The above description does not provide detailed explanations of the technical aspects of each layer's patterning, etching, etc. However, those skilled in the art should understand that various technical means can be used to form layers and regions of the desired shape. Furthermore, to form the same structure, those skilled in the art can also design methods that are not entirely identical to those described above. Additionally, although various embodiments have been described above, this does not mean that the measures in the various embodiments cannot be used advantageously in combination.

[0146] The embodiments of the present invention have been described above. However, these embodiments are merely for clarity and are not intended to limit the scope of the invention. The scope of the invention is defined by the appended claims and their equivalents. Various substitutions and modifications can be made by those skilled in the art without departing from the scope of the invention, and all such substitutions and modifications should fall within the scope of the invention.

Claims

1. A solar cell, characterized in that, include: A semiconductor substrate, the semiconductor substrate including opposing first and second surfaces; A first doped semiconductor layer is disposed on a local area of ​​the first surface; the first doped semiconductor layer includes a plurality of first strip-shaped regions extending along a first direction and spaced apart along a second direction; the first direction is different from the second direction; The first doped semiconductor layer includes a first boundary extending along the first direction and a second boundary extending along the second direction; the first boundary has a plurality of first protruding units that undulate toward the second direction and are sequentially distributed along the first direction, and the second boundary has a plurality of second protruding units that undulate toward the first direction and are sequentially distributed along the second direction; the width of the first protruding unit is smaller than the width of the second protruding unit.

2. The solar cell according to claim 1, characterized in that, The first doped semiconductor layer further includes a plurality of first connection regions; the first connection regions are disposed between at least two adjacent first strip regions and are electrically connected to the two adjacent first strip regions respectively; The boundary extending along the first direction in the first strip region has the first protruding unit; At least one of the first connecting region and the first strip region has a boundary extending along the second direction with the second protruding unit.

3. The solar cell according to claim 1, characterized in that, The solar cell further includes a second doped semiconductor layer; the second doped semiconductor layer and the first doped semiconductor layer have opposite doping types. The second doped semiconductor layer is disposed on the second surface; Alternatively, the second doped semiconductor layer and the first doped semiconductor layer are alternately distributed on the first surface; The extinction coefficient of the first doped semiconductor layer is greater than that of the second doped semiconductor layer.

4. The solar cell according to claim 3, characterized in that, When both the second doped semiconductor layer and the first doped semiconductor layer are disposed on the first surface, the second doped semiconductor layer includes a plurality of second strip regions extending along the first direction and spaced apart along the second direction; the second strip regions and the first strip regions are alternately spaced apart along the second direction; Wherein, the thickness of the first doped semiconductor layer is greater than the thickness of the second doped semiconductor layer; and / or, along the second direction, the width of the first strip region is greater than the width of the second strip region.

5. The solar cell according to claim 3, characterized in that, When both the second doped semiconductor layer and the first doped semiconductor layer are disposed on the first surface, the second doped semiconductor layer includes the third boundary extending along the first direction and the fourth boundary extending along the second direction; the third boundary has a plurality of third protruding units that undulate toward the second direction and are sequentially distributed along the first direction, and the fourth boundary has a fourth protruding unit that undulates toward the first direction and is sequentially distributed along the second direction. Wherein, the width of the first protruding unit is smaller than the width of the third protruding unit; And / or, the width of the first protruding unit is smaller than the width of the fourth protruding unit; And / or, the width of the second protruding unit is smaller than the width of the third protruding unit; And / or, the width of the second protruding unit is smaller than the width of the fourth protruding unit; And / or, the width of the third protruding unit is equal to the width of the fourth protruding unit.

6. The solar cell according to claim 5, characterized in that, The second doped semiconductor layer includes a plurality of second strip regions and a plurality of second connection regions; the plurality of second strip regions extend along the first direction and are spaced apart along the second direction; the second strip regions and the first strip regions are alternately spaced apart along the second direction; the second connection regions are disposed at least between two adjacent second strip regions and are electrically connected to the two adjacent second strip regions respectively; The boundary of the second strip-shaped region extending along the first direction has the third protruding unit; At least one of the second connecting area and the second strip area has the fourth protruding unit at its boundary extending along the second direction.

7. The solar cell according to claim 1, characterized in that, The first doped semiconductor layer has the opposite doping type to the semiconductor substrate; And / or, the doping type of the first doped semiconductor layer is P-type.

8. The solar cell according to any one of claims 1 to 7, characterized in that, In the first surface, the area where the first doped semiconductor layer is disposed is the first region, and the remaining area is the second region; The surface of the second region is provided with an array of textured structures; The texture structure includes multiple clustered texture structures spaced apart, with different clustered texture structures in the same row spaced apart along the first direction; or, the texture structure includes at least a fishbone-shaped texture structure or a grid-shaped texture structure continuously distributed along the first direction.

9. The solar cell according to claim 8, characterized in that, When the clustered texture structure is provided on the surface of the second region. Within the second region, the distance between two adjacent clustered texture structures located within the range of two first striped regions along the second direction and adjacent to each other along the first direction is the first distance; within the second region, the distance between two adjacent clustered texture structures located within the range of two first striped regions along the second direction and spaced apart along the second direction is the second distance, or, the distance between the clustered texture structure and the outline edge of the second region along the second direction is the second distance; the first distance is less than the second distance; And / or, the spacing between two adjacent clustered texture structures along the first direction is less than the minimum spacing between the clustered texture structure located on the outer side along the first direction and the edge of the second region contour.

10. The solar cell according to claim 8, characterized in that, When the clustered texture structure is provided on the surface of the second region, at least one of the clustered texture structures has a maximum size along the first direction that is greater than its maximum size along the second direction.

11. The solar cell according to claim 8, characterized in that, At least a portion of the surface of the second region is provided with the textured structure distributed in an array; The surface of the second region is also provided with a tower-shaped texture structure; the one-dimensional dimension of the tower-shaped texture structure is larger than the one-dimensional dimension of at least one of the texture structures; Wherein, the one-dimensional dimension of the texture structure is the one-dimensional dimension of the clustered texture structure, or the one-dimensional dimension of the texture structure is the width of a single texture strip in the fishbone texture structure or the grid texture structure.

12. The solar cell according to claim 8, characterized in that, When the clustered texture structure is provided on the surface of the second region, the clustered texture structure includes multiple pore structures.

13. The solar cell according to claim 8, characterized in that, When both the second doped semiconductor layer and the first doped semiconductor layer are disposed on the first surface. The second region includes a first sub-region and a second sub-region; the second doped semiconductor portion is disposed on the first sub-region; the second sub-region is located between the first sub-region and the first region, and is used to separate the first doped semiconductor layer and the second doped semiconductor layer. The texture structure is distributed on the surface of the first sub-region; and / or, the surface of the second sub-region is a velvety surface.

14. A method for manufacturing a solar cell, characterized in that, include: Provide a semiconductor substrate; The semiconductor substrate includes opposing first and second surfaces; A first doped semiconductor layer is formed on the first surface in a continuous manner; A laser etching process is used to pattern the first doped semiconductor layer using a rectangular laser spot, so that the remaining first doped semiconductor layer is located on a local area of ​​the first surface; the first doped semiconductor layer includes a plurality of first strip-shaped regions extending along a first direction and spaced apart along a second direction; the first direction is different from the second direction; the short side of the rectangular laser spot is approximately parallel to the first direction, and the long side of the rectangular laser spot is approximately parallel to the second direction. The first doped semiconductor layer includes a first boundary extending along the first direction and a second boundary extending along the second direction; the first boundary has a plurality of first protruding units that undulate toward the second direction and are sequentially distributed along the first direction, and the second boundary has a plurality of second protruding units that undulate toward the first direction and are sequentially distributed along the second direction; the width of the first protruding unit is greater than the width of the second protruding unit.

15. The method for manufacturing a solar cell according to claim 14, characterized in that, The overlap rate of the rectangular light spots along the first direction is greater than the overlap rate of the rectangular light spots along the second direction.

16. The method for manufacturing a solar cell according to claim 14, characterized in that, The method for manufacturing the solar cell further includes, after employing laser etching and patterning the first doped semiconductor layer using the rectangular laser spot: A second doped semiconductor layer is formed on the first surface in a continuous manner; the doping type of the second doped semiconductor layer is opposite to that of the first doped semiconductor layer, and the extinction coefficient of the first doped semiconductor layer is greater than that of the second doped semiconductor layer; A laser etching process is used, and the second doped semiconductor layer is patterned using a square laser spot so that the remaining second doped semiconductor layer is located on a local area of ​​the first surface, and the first doped semiconductor layer and the second doped semiconductor layer are distributed alternately.

17. The method for manufacturing a solar cell according to claim 16, characterized in that, The length of the longer side of the rectangular light spot is less than the side length of the square light spot; And / or, the length of the shorter side of the rectangular light spot is less than the side length of the square light spot; And / or, the illumination area of ​​a single rectangular light spot is smaller than the illumination area of ​​a single square light spot; And / or, along the second direction, the overlap rate of the rectangular light spot is less than the overlap rate of the square light spot.

18. A photovoltaic module, characterized in that, include: A battery string, wherein the battery string is formed by electrically connecting a plurality of solar cells as described in any one of claims 1 to 13; And an encapsulation layer that covers the surface of the battery string.

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