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 photovoltaic, and aims to enable a current collection electrode to have enough contact area with a doped semiconductor layer located in an edge region through a first opening and reduce contact resistance. The solar cell includes a semiconductor substrate, a doped semiconductor layer, a passivation layer, and a plurality of collector electrodes. The plurality of collector electrodes extend along the first direction and are distributed at intervals along the second direction. The passivation layer is internally provided with an opening, and the collector electrode is electrically connected with the doped semiconductor layer through the opening. The first face comprises an edge area and a middle area located on the inner side of the edge area and adjacent to the edge area. The opening in the edge area is defined as a first opening, and the opening in the middle area is defined as a second opening. The area corresponding to at least one first opening is larger than the area corresponding to the second opening.

Description

Technical Field

[0001] This invention relates to the field of photovoltaic technology, and in particular to a solar cell and 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 it, creating 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. Once connected to a circuit through the electrode structure, an electric current is generated. A passivation layer can be incorporated into the solar cell to reduce the carrier recombination rate. In this case, the electrode structure can be electrically connected to the p-region and n-region respectively through openings within the passivation layer, thus enabling the extraction of carriers.

[0003] However, in existing solar cells, carrier recombination is severe in the edge region of the cell, resulting in poor carrier collection. 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 enables the current collector electrode to have sufficient contact area with the doped semiconductor layer located in the edge region through at least one large first opening, thereby reducing contact resistance and improving carrier collection efficiency.

[0005] To achieve the above objectives, in a first aspect, the present invention provides a solar cell comprising: a semiconductor substrate, a doped semiconductor layer, a passivation layer, and a plurality of current collector electrodes. The semiconductor substrate includes a first surface and a second surface disposed opposite to each other. The doped semiconductor layer is disposed on the first surface. The passivation layer covers the side of the doped semiconductor layer facing away from the semiconductor substrate. The plurality of current collector electrodes are disposed on the side of the passivation layer facing away from the doped semiconductor layer. The plurality of current collector electrodes extend along a first direction and are spaced apart along a second direction, the first direction intersecting the second direction. An opening is provided in the passivation layer, through which the current collector electrodes are electrically connected to the doped semiconductor layer. The first surface includes two edge regions disposed opposite to each other and extending along the first direction, and a central region located between the two edge regions. The opening in the passivation layer located in the edge region is defined as a first opening, and the opening in the passivation layer located in the central region is defined as a second opening. The area of ​​at least one first opening is larger than the area of ​​at least one second opening.

[0006] With the above technical solution, the passivation layer has openings, each of which exposes a portion of the doped semiconductor layer. The current collector electrode, located on the side of the passivation layer facing away from the semiconductor substrate, can be electrically connected to a portion of the doped semiconductor layer through these openings, thus enabling carrier extraction. This eliminates the need to remove all the passivation layer directly below the current collector electrode, retaining the passivation layer between adjacent openings along the first direction. This allows for a larger passivation contact area between the passivation layer and the doped semiconductor layer, which helps reduce the carrier recombination rate. Furthermore, the solar cell provided by this invention features at least one first opening on the edge region of the first surface with a relatively large area (i.e., the area enclosed by the top contour of the opening). This ensures sufficient contact area between the current collector electrode and the doped semiconductor layer through the first opening, reducing contact resistance, improving carrier collection efficiency in the edge region, and reducing carrier recombination. In addition, due to limitations in patterning processes, it is difficult to form the first opening in the edge region. Therefore, setting the area of ​​at least one first opening in the edge region to be larger than the area of ​​the second opening is beneficial to increasing the area of ​​the doped semiconductor layer effectively exposed by at least one first opening (defined as the effective area). This also helps to ensure that the collector electrode can have sufficient contact area with the doped semiconductor layer through the first opening, thereby reducing the contact resistance.

[0007] As one possible implementation, the edge region includes two first regions arranged opposite each other along a first direction, and a second region located between the two first regions. The area of ​​the first opening in the first region is larger than the area of ​​the first opening in the second region.

[0008] By adopting the above technical solution, it is beneficial to ensure that the first opening in the passivation layer located at the corner of the solar cell has a large effective area, ensuring that the two ends of the collector electrode along the first direction can have sufficient contact area with the doped semiconductor layer through the first opening, reducing contact resistance, improving the carrier collection effect at the corner, and also improving the bonding stability of the two ends of the collector electrode along the first direction on the semiconductor substrate, thereby improving the yield of the solar cell.

[0009] As one possible implementation, the central region includes two third regions arranged opposite each other along a first direction, and a fourth region located between the two third regions. The area of ​​the second opening in the third region is larger than the area of ​​the second opening in the fourth region; and / or, the area of ​​the first opening in the edge region is larger than the area of ​​the second opening in the fourth region.

[0010] When the above technical solution is adopted, the beneficial effect of the area of ​​the second opening in the third region being greater than the area of ​​the second opening in the fourth region can be referred to the beneficial effect of the area of ​​the first opening in the first region being greater than the area of ​​the first opening in the second region as described above, and will not be repeated here.

[0011] Furthermore, since the second direction is the spacing distribution direction of different collector electrodes, the first opening on the edge region on both sides of the fourth region along the spacing distribution direction of the collector electrodes is set to have a large area. This ensures that the entire collector electrode on the edge region along the second direction can at least export the carriers collected by the doped semiconductor layer through the first opening with a large area. This prevents the problem that the carriers cannot be exported in time because the entire collector electrode is difficult to electrically connect with the doped semiconductor layer through the first opening (or can only be electrically connected with the doped semiconductor layer through the first opening with a small effective area). This reduces the carrier recombination rate and helps to improve the working performance of the solar cell.

[0012] As one possible implementation, the doped semiconductor layer includes N-type doped layers and P-type doped layers extending along a first direction and alternately arranged along a second direction. Specifically, the area of ​​at least one first opening on the P-type doped layer is smaller than the area of ​​at least one first opening on the N-type doped layer; and / or, the area of ​​at least one second opening on the P-type doped layer is smaller than the area of ​​at least one second opening on the N-type doped layer. In this case, it is advantageous to ensure a large passivation contact area between the passivation layer and the P-type doped layer, thus preventing the recombination of carriers collected by the P-type doped layer.

[0013] As one possible implementation, the thickness of the passivation layer located on the edge region is greater than the thickness of the passivation layer located on the middle region.

[0014] When using the above technical solution, due to the influence of slicing, film deposition, equipment, etc., the number of defects in the edge region of the first side of the solar cell is greater than the number of defects in the middle region. Setting a passivation layer with a larger thickness on the edge region can improve the passivation effect of the passivation layer on the edge region and reduce the carrier recombination in the edge region.

[0015] As one possible implementation, a protrusion structure is formed on the surface of the doped semiconductor layer facing away from the semiconductor substrate within the first opening, and the characteristic parameters of the protrusion structure on the edge region surface within the first opening are smaller than the characteristic parameters of the protrusion structure on the central region surface within the first opening. The characteristic parameters include at least one of quantity, density, and height. And / or, the doped semiconductor layer includes a first doped silicon layer and a second doped silicon layer disposed on at least a portion of the first doped silicon layer on the side facing away from the semiconductor substrate, the crystallinity of the second doped silicon layer being less than that of the first doped silicon layer, and the thickness of the second doped silicon layer in the edge region within the first opening being less than the thickness of the second doped silicon layer in the central region within the first opening.

[0016] When the above technical solution is adopted, if the number of protrusions on the surface of the central region within the first opening is large, the surface roughness of the central region of the first opening is large, which is beneficial to increasing the contact area between the doped semiconductor layer and the current collector electrode and reducing the contact resistance. Furthermore, compared with the highly crystallized first doped silicon layer, the less crystallized second doped silicon layer has a relatively higher passivation effect. When the thickness of the second doped silicon layer in the central region of the first opening is large, it can improve the passivation effect of the doped semiconductor layer on the semiconductor substrate at the portion corresponding to the first opening, compensating for the difference in passivation effect between different areas covered by the passivation layer in the first surface caused by the opening of the passivation layer, and improving the working performance of the solar cell. In addition, a large number of protrusions and / or a large thickness of the second doped silicon layer in the central region of the first opening indicate a high degree of irradiation of the passivation layer in the portion corresponding to the central region of the first opening using laser etching, ensuring that there is no residual passivation layer material in the central region of the first opening (or minimizing residual passivation layer material), which is beneficial to improving the contact performance between the current collector electrode and the doped semiconductor layer.

[0017] As one possible implementation, the edge region within the first opening includes residual passivation layer material. In this case, the passivation layer material in the edge region within the first opening can passivate the edge region of the first opening, compensating for the disadvantage of a smaller passivation contact area between the passivation layer and the doped semiconductor layer due to the large area corresponding to the first opening, thereby reducing carrier recombination in the edge region within the first opening. Simultaneously, it also helps protect the doped semiconductor layer beneath the passivation layer material in the edge region within the first opening, preventing damage to the doped semiconductor layer and ensuring a high field passivation effect.

[0018] As one possible implementation, along the second direction, the width of the first opening is equal to the width of the second opening. Along the first direction, the length of the first opening is greater than the length of the second opening. In this case, during the process of forming the first and second openings by etching the passivation layer using laser etching, it is not necessary to adjust the spot size. By adjusting the spot overlap rate and / or the number of spots along the second direction, first and second openings with different areas can be formed, which simplifies the etching process and improves etching efficiency.

[0019] As one possible implementation, the number of current collectors electrically connected to the doped semiconductor layer through the first opening is greater than or equal to 1 and less than or equal to 5. In this case, it can prevent the passivation contact area between the passivation layer and the doped semiconductor layer from being too small due to an excessive number of current collectors electrically connected to the doped semiconductor layer through the first opening, which is beneficial to ensure that the passivation layer has a high passivation effect on the doped semiconductor layer. At the same time, if the number of current collectors electrically connected to the doped semiconductor layer through the first opening is too large, that is, if the first opening area is also set at the middle position or near the middle position of the solar cell, it will cause a large degree of thermal damage to the doped semiconductor layer at the middle position or near the middle position of the solar cell. Therefore, setting the number of current collectors electrically connected to the doped semiconductor layer through the first opening to less than or equal to 5 can reduce or even avoid thermal damage to the doped semiconductor layer at the middle position or near the middle position of the solar cell.

[0020] As one possible implementation, the doped semiconductor layer includes N-type and P-type doped layers extending along a first direction and alternately arranged along a second direction. The collector electrode includes a first collector electrode and a second collector electrode alternately spaced along the second direction. The first collector electrode is electrically connected to the N-type doped layer, and the second collector electrode is electrically connected to the P-type doped layer. The number of first collector electrodes electrically connected to the N-type doped layer through a first opening is less than the number of second collector electrodes electrically connected to the P-type doped layer through the first opening.

[0021] When the above technical solution is adopted, if the number of first collector electrodes electrically connected to the N-type doped layer through the first opening is small, it can prevent thermal damage to the N-type doped layer caused by excessive laser irradiation during etching of the passivation layer on the inner side of the N-type doped layer along the direction from the edge region to the middle region. This ensures a high yield of the N-type doped layer and helps to ensure a large passivation contact area between the passivation layer and the N-type doped layer. In addition, since the conductivity of the P-type doped layer is relatively poor compared to the N-type doped layer, a larger number of second collector electrodes electrically connected to the P-type doped layer through the first opening can ensure sufficient carrier collection contact area between the second collector electrode and the outer P-type doped layer along the direction from the middle region to the edge region, ensuring the hole collection effect in the edge region.

[0022] As one possible implementation, the number of first collector electrodes electrically connected to the N-type doped layer through the first opening is greater than or equal to 1 and less than or equal to 3; and / or, the number of second collector electrodes electrically connected to the P-type doped layer through the first opening is greater than or equal to 2 and less than or equal to 5.

[0023] As one possible implementation, the doped semiconductor layer includes an N-type doped layer and a P-type doped layer that extend along a first direction and are alternately arranged along a second direction. The collector electrode includes a first collector electrode and a second collector electrode that are alternately spaced along the second direction, with the first collector electrode electrically connected to the N-type doped layer and the second collector electrode electrically connected to the P-type doped layer.

[0024] In this configuration, both the P-type and N-type doped layers have raised structures on the surface of the regions exposed at the first opening, on the side facing away from the semiconductor substrate. Along the second direction, the characteristic parameters of the raised structures within the first opening corresponding to the first collector electrode farther from the edge region are greater than the characteristic parameters of the raised structures within the first opening corresponding to the first collector electrode closer to the edge region, and / or, the characteristic parameters of the raised structures within the first opening corresponding to the second collector electrode farther from the edge region are greater than the characteristic parameters of the raised structures within the first opening corresponding to the second collector electrode closer to the edge region. The characteristic parameters include at least one of number, density, and height.

[0025] And / or, both the P-type doped layer and the N-type doped layer include a first doped silicon layer and a second doped silicon layer disposed on at least a portion of the side of the first doped silicon layer facing away from the semiconductor substrate, wherein the crystallinity of the second doped silicon layer is less than that of the first doped silicon layer. The thickness of the second doped silicon layer within the first opening corresponding to the first collector electrode far from the edge region is greater than the thickness of the second doped silicon layer within the first opening corresponding to the first collector electrode near the edge region, and / or, the thickness of the second doped silicon layer within the first opening corresponding to the second collector electrode far from the edge region is greater than the thickness of the second doped silicon layer within the first opening corresponding to the second collector electrode near the edge region.

[0026] In the above technical solution, in the first surface of the semiconductor substrate, since the central region mainly ensures the collection of charge carriers, the characteristic parameters of the protrusion structure in the first opening corresponding to the second collector electrode, which is farther from the edge region, are greater than those of the protrusion structure in the first opening corresponding to the second collector electrode near the edge region. This is advantageous because the surface area of ​​the P-type doped layer exposed in the first opening on the inner side along the direction from the edge region to the central region has a larger specific surface area, which helps to increase the contact area between the P-type doped layer and the second collector electrode at this location. This ensures that the charge carriers collected by the P-type doped layer in the high-efficiency part of the edge region near the central region can be promptly discharged. Furthermore, as mentioned above, the passivation effect of the second doped silicon layer is higher than that of the first doped silicon layer. Therefore, when the thickness of the second doped silicon layer in the first opening corresponding to the second collector electrode farther from the edge region is greater than that in the first opening corresponding to the second collector electrode near the edge region, it ensures that the second doped silicon layer has a very high passivation effect on the high-efficiency part of the edge region near the central region, reducing the recombination of charge carriers at the inner first opening.

[0027] As one possible implementation, the passivation layer includes a laser irradiation area, which includes a first opening, a second opening, and laser-affected areas located at the outer peripheries of the first opening and the second opening, respectively. The passivation layer is disposed within the laser-affected areas. The thickness of the passivation layer located in the laser-affected areas is less than the thickness of the passivation layer outside the laser irradiation areas; and / or, the width of the laser-affected area located at the outer periphery of the first opening is greater than the width of the laser-affected area located at the outer periphery of the second opening.

[0028] When the above technical solution is adopted, a smaller thickness of the passivation layer in the laser-affected zone helps reduce the residual passivation layer material in the first and second openings inside the laser-affected zone, ensuring that the current collector electrode can pass through the first and second openings and have a larger contact area with the doped semiconductor layer, thus reducing contact resistance. Furthermore, it allows the laser energy to be distributed gradually from the first opening (or the second opening) to the laser-affected zone, making the laser spot easier to control and simplifying the manufacturing process.

[0029] Furthermore, during the laser etching process to form an opening in the passivation layer, the laser spot has higher energy in the center, enabling it to penetrate the passivation layer and form the opening. However, the energy at the edge of the laser spot is relatively low, failing to penetrate the passivation layer and thus forming a laser-affected zone. In this case, the laser-affected zone located around the periphery of the first opening has a relatively large width. During the actual fabrication process, the laser spot corresponding to the first opening has higher irradiation energy, which is beneficial for removing the thicker passivation layer within the first opening at the edge region. This reduces the amount of passivation layer material residue within the first opening and helps ensure sufficient contact area between the current collector electrode and the doped semiconductor layer.

[0030] As one possible implementation, along the second direction, the width of the laser irradiation area around the outer periphery of the first opening is equal to the width of the laser irradiation area around the outer periphery of the second opening. The length of the laser irradiation area around the outer periphery of the first opening along the first direction is greater than the length of the laser irradiation area around the outer periphery of the second opening along the first direction. The application principle of the beneficial effect in this case can refer to the application principle of the beneficial effect described above where the width of the first opening is equal to the width of the second opening along the second direction, and the length of the first opening is greater than the width of the second opening, which will not be repeated here.

[0031] As one possible implementation, the laser irradiation area of ​​the first opening has multiple light spot irradiation sub-regions that partially overlap along a first direction. Specifically, along the first direction, within the same laser irradiation area, the overlap rate between two adjacent light spot irradiation sub-regions is greater than or equal to 30% and less than 100%; and / or, within the same laser irradiation area, the minimum distance between the same side boundary lines extending along a second direction of two adjacent light spot irradiation sub-regions is greater than 0 and less than or equal to 50 μm.

[0032] With the above technical solution, it is understood that the laser irradiation energy is higher in the overlapping area of ​​two adjacent laser spots, making it easier to completely remove the passivation layer. Therefore, within the same laser irradiation area, if the overlap rate of two adjacent spot irradiation sub-regions is within the aforementioned range, it can prevent a small overlap rate from resulting in a larger proportion of areas with lower laser irradiation energy within the first opening, leading to a greater amount of residual passivation layer material. This helps ensure sufficient contact area between the collector electrode and the doped semiconductor layer located at the edge region. Furthermore, it can prevent damage to the doped semiconductor layer and reduced manufacturing efficiency caused by a large overlap rate, thus helping to ensure a high yield of the doped semiconductor layer. The beneficial effects of having a minimum spacing of greater than 0 and less than or equal to 50 μm between the boundary lines of two adjacent spot irradiation sub-regions extending along the second direction within the same laser irradiation area can be referred to the previous text and will not be repeated here.

[0033] As one possible implementation, the doped semiconductor layer includes N-type doped layers and P-type doped layers that extend along a first direction and are alternately arranged along a second direction. The passivation layer includes a laser irradiation region, which includes a first opening, a second opening, and laser-affected regions located at the outer peripheries of the first and second openings, respectively. The laser irradiation region has multiple light spot irradiation sub-regions that partially overlap along the first direction. Specifically, the overlap rate between two adjacent light spot irradiation sub-regions in the laser irradiation region corresponding to the P-type doped layer and including the first opening is greater than the overlap rate between two adjacent light spot irradiation sub-regions in the laser irradiation region corresponding to the N-type doped layer and including the first opening; and / or, the minimum spacing between the boundary lines extending along the second direction in the laser irradiation region corresponding to the P-type doped layer and including the first opening in the laser irradiation region is less than the minimum spacing between the boundary lines extending along the second direction in the laser irradiation region corresponding to the N-type doped layer and including the first opening in the laser irradiation region.

[0034] As mentioned earlier, when using the above technical solution, the conductivity of the P-type doped layer is worse than that of the N-type doped layer. Therefore, by setting a higher overlap rate between adjacent irradiated sub-regions in the laser irradiation region corresponding to the P-type doped layer, the proportion of non-overlapping areas in the laser irradiation region is reduced. This allows more local areas in the laser irradiation region corresponding to the P-type doped layer to receive higher laser irradiation energy, ensuring that the first opening can expose a portion of the P-type doped layer located below it. It also helps reduce the amount of passivation layer material remaining in the first opening, providing sufficient contact area between the second current collector and the P-type doped layer, reducing contact resistance and carrier recombination. Simultaneously, it also helps prevent the N-type doped layer from being affected by excessively high-energy laser irradiation, reducing thermal damage to the N-type doped layer. As for the beneficial effect of the minimum spacing between the boundary lines extending along the second direction in two adjacent light spot irradiation sub-regions in the laser irradiation region including the first opening of the P-type doped layer being smaller than the minimum spacing between the boundary lines extending along the second direction in two adjacent light spot irradiation sub-regions in the laser irradiation region including the first opening of the N-type doped layer, please refer to the previous text.

[0035] As one possible implementation, the thickness of the passivation layer at the four corners of the solar cell is greater than the thickness of the passivation layer at other locations.

[0036] As one possible implementation, in the edge region, the area of ​​the passivation layer material remaining in the edge region within the first opening at the four corners of the solar cell is larger than the area of ​​the passivation layer material remaining in the edge region within the first opening at other locations. This configuration results in a larger area of ​​passivation layer material remaining in the edge region within the openings at the four corners of the first surface, which is beneficial for improving the passivation effect of the passivation layer at these locations and reducing carrier recombination.

[0037] As one possible implementation, in the edge region, a protrusion structure is formed on the surface of the doped semiconductor layer on the side facing away from the semiconductor substrate, exposed at the first opening. The characteristic parameters of the protrusion structure within the first opening at the corner of the solar cell are smaller than those of the protrusion structures within the first opening at other locations. The characteristic parameters include at least one of quantity, density, and height. The application principle of the beneficial effects in this case can be referred to above.

[0038] As one possible implementation, the doped semiconductor layer includes a first doped silicon layer and a second doped silicon layer disposed on at least a portion of the side of the first doped silicon layer facing away from the semiconductor substrate. The crystallinity of the second doped silicon layer is less than that of the first doped silicon layer. In the edge region, the thickness of the second doped silicon layer within the first opening at the corner of the solar cell is less than the thickness of the second doped silicon layer within the first opening at other locations. The application principle of the beneficial effects in this case can be referred to the preceding text.

[0039] As one possible implementation, the doped semiconductor layer includes an N-type doped layer and a P-type doped layer that extend along a first direction and are alternately arranged along a second direction.

[0040] In this embodiment, on the edge region, a raised structure is formed within the first opening on the surface of the doped semiconductor layer facing away from the semiconductor substrate. On the edge region of the first surface, the characteristic parameters of the raised structure within the first opening corresponding to the N-type doped layer are greater than the characteristic parameters of the raised structure within the first opening corresponding to the P-type doped layer. The characteristic parameters include at least one of the following: number, density, and height.

[0041] And / or, both the N-type doped layer and the P-type doped layer include a first doped silicon layer and a second doped silicon layer disposed on at least a portion of the side of the first doped silicon layer facing away from the semiconductor substrate, wherein the crystallinity of the second doped silicon layer is less than that of the first doped silicon layer. In the edge region of the first surface, the thickness of the second doped silicon layer within the first opening corresponding to the N-type doped layer is greater than the thickness of the second doped silicon layer within the first opening corresponding to the P-type doped layer.

[0042] And / or, the area of ​​the passivation layer material remaining in the first opening corresponding to the P-type doped layer located at the four corners of the solar cell is greater than the area of ​​the passivation layer material remaining in the first opening corresponding to the N-type doped layer located at the four corners of the solar cell.

[0043] When the above technical solution is adopted, a larger characteristic parameter of the protrusion structure within the first opening corresponding to the N-type doped layer is beneficial for increasing the surface roughness of the N-type doped layer exposed at the first opening, increasing the contact area between the N-type doped layer and the collector electrode, and ensuring higher contact performance between the N-type doped layer and the collector electrode. Furthermore, the application principle of the beneficial effect of the thickness of the second doped silicon layer within the first opening corresponding to the N-type doped layer being greater than the thickness of the second doped silicon layer within the first opening corresponding to the P-type doped layer can be referred to the application principle of the beneficial effect of the larger characteristic parameter of the protrusion structure within the first opening corresponding to the N-type doped layer described above, and will not be repeated here.

[0044] As one possible implementation, the collector electrode includes a seed layer located on the doped semiconductor layer and corresponding to the first opening or the second opening, and a metal layer located on the seed layer. The seed layer is in contact with the doped semiconductor layer through the first opening or the second opening. The thickness of the seed layer located at the edge region of the first opening is greater than the thickness of the seed layer located in the central region of the first opening; and / or, the thickness of the seed layer located at the edge region of the second opening is greater than the thickness of the seed layer located in the central region of the second opening.

[0045] When using the above technical solution, during the laser etching process to form the opening by etching the passivation layer, the energy at the edge of the laser spot is relatively low (compared to the center of the spot), resulting in residual passivation layer material in the edge region of the opening. While this residual passivation layer material can improve the passivation effect, it also hinders the connection between the current collector electrode and the doped semiconductor layer. Therefore, taking the first opening as an example: setting a seed layer with a larger thickness in the edge region of the first opening can compensate for the disadvantage of the residual passivation layer material hindering carrier transport, thus improving the contact performance between the seed layer and the doped semiconductor layer in the edge region of the first opening and improving carrier collection efficiency. Furthermore, while improving edge contact performance, the thicker seed layer in the edge region of the first opening can also prevent the upper metal layer from entering the bottom layer from the edge, reducing metal recombination loss and improving contact performance.

[0046] As one possible implementation, the doped semiconductor layer includes an N-type doped layer and a P-type doped layer that extend along a first direction and are alternately arranged along a second direction.

[0047] The difference between the thickness of the seed layer in the edge region of the first opening corresponding to the N-type doped layer and the thickness of the seed layer in the middle region is less than the difference between the thickness of the seed layer in the edge region of the first opening corresponding to the P-type doped layer and the thickness of the seed layer in the middle region.

[0048] And / or, the difference between the thickness of the seed layer in the edge region of the second opening corresponding to the N-type doped layer and the thickness of the seed layer in the middle region is less than the difference between the thickness of the seed layer in the edge region of the second opening corresponding to the P-type doped layer and the thickness of the seed layer in the middle region.

[0049] And / or, the surface roughness of the portion of the N-type doped layer exposed in the first opening is greater than the surface roughness of the portion of the P-type doped layer exposed in the first opening.

[0050] And / or, the surface roughness of the portion of the N-type doped layer exposed in the second opening is greater than the surface roughness of the portion of the P-type doped layer exposed in the second opening.

[0051] When the above technical solution is adopted, if the difference between the thickness of the seed layer in the edge region and the thickness of the seed layer in the middle region of the first opening corresponding to the N-type doped layer is small, the uniformity of the seed layer thickness in the first opening corresponding to the N-type doped layer is high. This is beneficial for providing a smoother stress transition at the contact surface between the seed layer and the metal layer, reducing stress accumulation at the contact surface, and avoiding the generation of cracks or gaps. Compared with the N-type doped layer, the P-type doped layer has weaker carrier separation and transport capabilities, resulting in the need to reinforce the carrier transport channels. Based on this, if the difference between the thickness of the seed layer in the edge region and the thickness of the seed layer in the middle region of the first opening corresponding to the P-type doped layer is large, it is beneficial to increase the surface area of ​​the seed layer, thereby increasing the contact area between the seed layer and the metal layer, reducing the contact resistance, and facilitating the timely discharge of carriers. In addition, the application principle of the beneficial effect of the larger surface roughness of the part of the N-type doped layer exposed in the first opening can refer to the application principle of the beneficial effect of the larger characteristic parameters of the protrusion structure in the first opening corresponding to the N-type doped layer described above, which will not be repeated here.

[0052] Secondly, 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.

[0053] 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.

[0054] Thirdly, the present invention provides a method for fabricating a solar cell, the method comprising: first, providing a semiconductor substrate. The semiconductor substrate includes a first surface and a second surface disposed opposite to each other. The first surface includes two edge regions disposed opposite to each other and extending along a first direction, and a central region located between the two edge regions. Next, forming a doped semiconductor layer on the first surface. Next, forming a passivation layer on the side of the doped semiconductor layer opposite to the semiconductor substrate. Next, forming an opening in the passivation layer. The opening in the edge region of the passivation layer is defined as a first opening, and the opening in the central region of the passivation layer is defined as a second opening. The area of ​​at least one first opening is larger than the area of ​​at least one second opening. Next, forming a plurality of current collector electrodes on the side of the passivation layer opposite to the doped semiconductor layer. The plurality of current collector electrodes extend along the first direction and are spaced apart along a second direction, the first direction intersecting the second direction. The current collector electrodes pass through the first opening and the second opening and are electrically connected to the doped semiconductor layer.

[0055] One possible implementation involves forming an opening in the passivation layer, including: using a laser etching process and overlapping m laser spots in the edge region to form a first opening, where m is a positive integer greater than or equal to 2; and using a laser etching process and irradiating with one laser spot or overlapping n laser spots in the central region to form a second opening, where n is a positive integer greater than or equal to 2 and less than m.

[0056] In one possible implementation, the doped semiconductor layer includes N-type doped layers and P-type doped layers that extend along a first direction and are alternately arranged along a second direction. A laser etching process is used, with a laser spot having a first laser power to create a first opening and a second opening at the location of the passivation layer corresponding to the P-type doped layer. Alternatively, a laser etching process is used, with a laser spot having a second laser power to create a first opening and a second opening at the location of the passivation layer corresponding to the N-type doped layer. The first laser power is different from the second laser power.

[0057] 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

[0058] 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: Figure 1 A longitudinal sectional view of the structure of a solar cell provided in an embodiment of the present invention. Figure 1 ; Figure 2 A longitudinal sectional view of the structure of a solar cell provided in an embodiment of the present invention. Figure 2 ; Figure 3 This is a schematic diagram illustrating the distribution of openings within the passivation layer in a solar cell provided in an embodiment of the present invention. Figure 1 ; Figure 4 This is a schematic diagram illustrating the distribution of openings within the passivation layer in a solar cell provided in an embodiment of the present invention. Figure 2 ; Figure 5 SEM image of the opening distribution in the third region of the solar cell provided in the embodiment of the present invention; Figure 6 SEM image of an opening disposed on an N-type doped layer in a solar cell provided in an embodiment of the present invention. Figure 1 ; Figure 7 This is a schematic diagram of different openings disposed on the doped semiconductor layer in a solar cell provided in an embodiment of the present invention; Figure 8 SEM image of an opening disposed on an N-type doped layer in a solar cell provided in an embodiment of the present invention. Figure 2 ; Figure 9 SEM image of an opening disposed on a p-type doped layer in a solar cell provided in an embodiment of the present invention. Figure 1 ; Figure 10 This is a SEM image of the morphology of the protrusion structure in the solar cell provided in an embodiment of the present invention; Figure 11 A longitudinal sectional view of the structure of a solar cell provided in an embodiment of the present invention. Figure 3 ; Figure 12 This is a SEM image of the seed layer within the first opening of the N-type doped layer in a solar cell provided in an embodiment of the present invention. Figure 13 This is a SEM image of the seed layer within the first opening of the p-type doped layer in a solar cell provided in an embodiment of the present invention. Figure 14 A schematic diagram of the structure of a solar cell during the fabrication process provided in an embodiment of the present invention. Figure 1 ; Figure 15 A schematic diagram of the structure of a solar cell during the fabrication process provided in an embodiment of the present invention. Figure 2 ; Figure 16 A schematic diagram of the structure of a solar cell during the fabrication process provided in an embodiment of the present invention. Figure 3 ; Figure 17 A schematic diagram of the structure of a solar cell during the fabrication process provided in an embodiment of the present invention. Figure 4 .

[0059] Reference numerals: 11 is semiconductor substrate, 12 is doped semiconductor layer, 13 is passivation layer, 14 is collector electrode, 15 is edge region, 16 is central region, 17 is first region, 18 is first opening, 19 is second opening, 20 is protrusion structure, 21 is first doped silicon layer, 22 is second doped silicon layer, 23 is N-type doped layer, 24 is P-type doped layer, 25 is laser irradiation area, 26 is laser-affected area, 27 is light spot irradiation sub-region, 28 is second region, 29 is seed layer, 30 is third region, and 31 is fourth region. Detailed Implementation

[0060] 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.

[0061] 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.

[0062] 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.

[0063] 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.

[0064] 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.

[0065] In a first aspect, embodiments of the present invention provide a solar cell. For example... Figure 1 and Figure 2As shown, the solar cell includes: a semiconductor substrate 11, a doped semiconductor layer 12, a passivation layer 13, and a plurality of current collector electrodes 14. The semiconductor substrate 11 includes a first surface and a second surface disposed opposite to each other. The doped semiconductor layer 12 is disposed on the first surface. The passivation layer 13 covers the side of the doped semiconductor layer 12 facing away from the semiconductor substrate 11. The plurality of current collector electrodes 14 are disposed on the side of the passivation layer 13 facing away from the doped semiconductor layer 12. The plurality of current collector electrodes 14 extend along a first direction and are spaced apart along a second direction, the first direction intersecting the second direction. An opening is provided in the passivation layer 13, through which the current collector electrodes 14 are electrically connected to the doped semiconductor layer 12.

[0066] In the embodiments of the present invention, the size and shape of the opening can be set according to actual needs.

[0067] When the above technical solution is adopted, such as Figure 1 and Figure 2 As shown, the passivation layer 13 has openings, each of which exposes a portion of the doped semiconductor layer 12. The collector electrode 14, located on the side of the passivation layer 13 facing away from the semiconductor substrate 11, can be electrically connected to a portion of the doped semiconductor layer 12 through the openings, thus enabling carrier extraction. This eliminates the need to remove all of the passivation layer 13 directly below the collector electrode 14, retaining the passivation layer 13 between two adjacent openings along the first direction. This allows for a larger passivation contact area between the passivation layer 13 and the doped semiconductor layer 12, which helps reduce the carrier recombination rate.

[0068] In practical applications, this invention does not specifically limit the material and conductivity type of the semiconductor substrate. For example, the semiconductor substrate can be any semiconductor material such as silicon, germanium-silicon, or germanium. The conductivity type of the semiconductor substrate can be P-type, N-type, or intrinsic.

[0069] In addition, the correspondence between the first and second surfaces of the semiconductor substrate and the front and back surfaces of the solar cell can be determined based on the type of solar cell and the distribution range of the doped semiconductor layer in the solar cell in the actual application scenario.

[0070] For example, in the case of a double-sided contact solar cell, the first side of the semiconductor substrate may correspond to the front side of the solar cell, in which case the second side of the semiconductor substrate may correspond to the back side of the solar cell. Alternatively, the first side of the semiconductor substrate may correspond to the back side of the solar cell, in which case the second side of the semiconductor substrate may correspond to the front side of the solar cell.

[0071] For example, such as Figure 2As 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, and the second surface of the semiconductor substrate 11 corresponds to the front surface of the solar cell.

[0072] For doped semiconductor layers, the structure and conductivity type of the doped semiconductor layer, as well as the range of the doped semiconductor layer on the semiconductor substrate, can be set according to the type of solar cell and actual needs.

[0073] For example, in the case of a double-sided contact solar cell, the doped semiconductor layer can be disposed on a local area of ​​the first side of the semiconductor substrate, or it can be disposed on the entire first side. The doped semiconductor layer can be an N-type doped layer or a P-type doped layer.

[0074] For example, in the case of a back-contact solar cell, the doped semiconductor layer can be an N-type doped layer or a P-type doped layer, in which case the doped semiconductor layer is disposed on a local region of the first surface of the semiconductor substrate. Alternatively, as... Figure 2 As shown, the doped semiconductor layer 12 may also include an N-type doped layer 23 and a P-type doped layer 24 that extend along a first direction and are spaced apart along a second direction; in this case, the collector electrode 14 may include a first collector electrode and a second collector electrode that are alternately spaced along the second direction, the first collector electrode being electrically connected to the N-type doped layer 23 and the second collector electrode being electrically connected to the P-type doped layer 24.

[0075] The material and thickness of the doped semiconductor layer can be set according to actual needs. For example, the material of the doped semiconductor layer can include any semiconductor material such as silicon, germanium-silicon, germanium, or gallium arsenide. In terms of the arrangement of matter, the crystal phase of the doped semiconductor layer can be amorphous, microcrystalline, nanocrystalline, single-crystal, or polycrystalline. Optionally, the doped semiconductor layer can include a doped polycrystalline silicon layer.

[0076] Furthermore, when the doped semiconductor layer includes both N-type and P-type doped layers, the materials of the N-type and P-type doped layers can be the same; for example, the materials of both the N-type and P-type doped layers can be doped polycrystalline silicon, doped amorphous silicon, doped microcrystalline silicon, or doped nanocrystalline silicon, etc. Alternatively, the materials of the N-type and P-type doped layers can also be different; for example, the material of the N-type doped layer can include doped polycrystalline silicon, and the material of the P-type doped layer can include at least one of doped amorphous silicon, doped microcrystalline silicon, and doped nanocrystalline silicon.

[0077] In addition, such as Figure 1 As shown, the doped semiconductor layer 12 can be directly disposed on the first surface. Or, as... Figure 2As shown, the back contact battery may further include an interface passivation layer disposed between the doped semiconductor layer 12 and the first surface to reduce the carrier recombination rate. The material and thickness of the interface passivation layer can be set according to the material of the doped semiconductor layer 12 and actual needs, and are not specifically limited here. For example, when the material in the doped semiconductor layer closest to the semiconductor substrate includes doped polycrystalline silicon, the interface passivation layer is a tunneling oxide layer. As another example, when the material in the doped semiconductor layer closest to the semiconductor substrate includes at least one of doped amorphous silicon, doped microcrystalline silicon, and doped nanocrystalline silicon, the interface passivation layer is an intrinsic amorphous silicon layer, an intrinsic microcrystalline silicon layer, an intrinsic nanocrystalline silicon layer, or a mixture of the above three.

[0078] For a passivation layer, the passivation layer covers the side of the doped semiconductor layer that faces away from the semiconductor substrate. The material of the passivation layer can include any material with passivation function, such as silicon oxide, silicon nitride, or aluminum oxide.

[0079] It should be noted that the definition of the first surface includes two edge regions that are opposite to each other and extend along a first direction, and a central region located between the two edge regions. In this case, as... Figure 1 and Figure 2 As shown, the material of the passivation layer 13 located in the central region 16 can be the same as the material of the passivation layer 13 located in the edge region 15. For example, the material of the passivation layer located in the central region and the material of the passivation layer located in the edge region can both include silicon nitride and / or aluminum oxide, etc.

[0080] Alternatively, the material of the passivation layer located in the central region may be the same as only a portion of the material of the passivation layer located in the edge region. For example, the material of the passivation layer located in the central region may include silicon nitride and / or aluminum oxide, while the material of the passivation layer located in the edge region may include silicon oxide, in addition to silicon nitride and / or aluminum oxide.

[0081] The thickness of the passivation layer can be determined based on the material of the passivation layer and the actual application scenario. The thickness of the passivation layer in different regions of the first surface can be approximately the same.

[0082] Alternatively, the thickness of the passivation layer located on the edge region can be greater than the thickness of the passivation layer located on the central region. In this case, due to the influence of slicing, film deposition, equipment, etc., the number of defects in the edge region on one side of the first surface of the solar cell is greater than the number of defects in the central region. Setting the passivation layer on the edge region to have a larger thickness can improve the passivation effect of the passivation layer on the edge region and reduce the carrier recombination rate in the edge region.

[0083] The extent of the edge and central regions in the first surface can be determined based on the size of the semiconductor substrate, the characteristics of the deposition process during passivation layer fabrication, and other practical requirements such as the extent of the plating. No specific limitations are made here. Furthermore, the difference in thickness between the passivation layer located in the edge region and the passivation layer located in the central region can be determined based on the characteristics of the deposition process during passivation layer fabrication and the plating details.

[0084] An opening in the passivation layer located at the edge region is defined as a first opening, and an opening in the passivation layer located in the middle region is defined as a second opening. For example, as shown... Figure 3 As shown, the area of ​​at least one first opening 18 can be larger than the area of ​​at least one second opening 19. In this case, setting at least one first opening 18 located on the edge region 15 in the first surface to have a relatively large area (i.e., the area enclosed by the top contour of the opening) helps ensure that the collector electrode 14 can have sufficient contact area with the doped semiconductor layer 12 through the first opening 18, reducing contact resistance, improving the carrier collection efficiency of the edge region 15, and reducing carrier recombination. In addition, due to the influence of factors such as equipment and the film layer itself, it is difficult to form the first opening 18 in the edge region 15. Therefore, setting the area of ​​at least one first opening 18 located in the edge region 15 to be larger than the area of ​​the second opening 19 helps to increase the area of ​​the doped semiconductor layer 12 effectively exposed by at least one first opening 18 (defined as the effective area), which also helps to ensure that the collector electrode 14 can have sufficient contact area with the doped semiconductor layer 12 through the first opening 18, reducing contact resistance.

[0085] In practical applications, the area of ​​a single first opening located on the edge region (which can be any first opening located on the edge region) can be greater than the area of ​​a second opening located on the central region (which can be any second opening located on the edge region).

[0086] Alternatively, the area of ​​all the first openings located on the edge region may be greater than the area of ​​the only second opening located on the central region (which may be any second opening located on the edge region).

[0087] Alternatively, the area of ​​a single first opening located on the edge region (which can be any first opening located on the edge region) may be greater than the area of ​​all the second openings located on the central region.

[0088] Alternatively, the area of ​​all the first openings located on the edge region could be greater than the area of ​​all the second openings located on the middle region.

[0089] The edge region is defined as two first regions arranged opposite each other along a first direction, and a second region located between the two first regions. The middle region includes two third regions arranged opposite each other along the first direction, and a fourth region located between the two third regions.

[0090] For example, such as Figure 3 and Figure 4 As shown, the area of ​​the first opening 18 located on the edge region 15 can be larger than the area of ​​the second opening 19 located on the fourth region 31. With this configuration, since the second direction is the spacing direction of different collector electrodes 14, the first opening 18 on the edge regions 15 located on both sides of the fourth region 31 along the spacing direction of the collector electrodes 14 is set to have a larger area. This ensures that the entire collector electrode 14 located on the edge region 15 along the second direction can at least export the carriers collected by the doped semiconductor layer 12 through the first opening 18 with a larger area. This prevents the problem of carriers not being exported in time because the entire collector electrode 14 is difficult to electrically connect with the doped semiconductor layer 12 through the first opening 18 (or can only be electrically connected with the doped semiconductor layer 12 through the first opening 18 with a smaller effective area), thereby reducing the carrier recombination rate and improving the working performance of the solar cell.

[0091] For example, such as Figure 3 and Figure 4 As shown, the area of ​​the first opening 18 located in the second region 28 may be greater than the area of ​​the second opening 19 located in the fourth region 31.

[0092] It should be noted that in practical applications, when the same laser spot is used and the first and second openings are formed under the same irradiation parameters such as laser power and overlap rate, the area of ​​at least one first opening may be less than or equal to the area of ​​the second opening.

[0093] The difference in area between the first opening and the second opening can be set according to the difference in carrier collection requirements between the edge region and the middle region of the first surface, the difference in the thickness of the passivation layer located in the edge region and the middle region, and other practical needs. No specific limitation is made here.

[0094] The difference in area between the first opening and the second opening can be achieved by the first opening having a wider width than the second opening along the second direction, and / or the first opening having a longer length than the second opening along the first direction.

[0095] Optional, such as Figure 3 and Figure 4As shown, along the second direction, the width of the first opening 18 can be equal to the width of the second opening 19; and along the first direction, the length of the first opening 18 is greater than the length of the second opening 19. In this case, during the process of forming the first opening 18 and the second opening 19 by etching the passivation layer 13 through laser etching, it is not necessary to adjust the spot size. By adjusting the spot overlap rate and / or the number of spots along the second direction, the first opening 18 and the second opening 19 with different areas can be formed, which helps to simplify the etching process and improve the etching efficiency.

[0096] It should be noted that, due to the different positions of the first and second openings in the passivation layer, and the influence of measurement accuracy, even if the actual widths of the first and second openings are the same, their measured width values ​​may differ. Therefore, in this embodiment of the invention, the width of the first opening equal to the width of the second opening means that the insulation value of the difference between the widths of the first and second openings is less than or equal to the value due to positional differences and measurement errors (e.g., 10 μm).

[0097] The sizes of the different first openings on the edge region can be the same or different. The sizes of the different second openings on the central region can be the same or different.

[0098] For example, such as Figure 3 As shown, the area of ​​the first opening 18 located in the first region 17 can be larger than the area of ​​the first opening 18 located in the second region 28. This arrangement helps to ensure that the first opening 18 located in the passivation layer 13 at the corner of the solar cell has a larger effective area, ensuring that the two ends of the current collector electrode 14 along the first direction can have sufficient contact area with the doped semiconductor layer 12 through the first opening 18, reducing contact resistance, improving the carrier collection effect at the corner, and also improving the bonding stability of the two ends of the current collector electrode 14 along the first direction on the semiconductor substrate 11, thereby improving the yield of the solar cell.

[0099] For example, such as Figure 4 As shown, the area of ​​the second opening 19 located in the third region 30 can be larger than the area of ​​the second opening 19 located in the fourth region 31. The application principle of the beneficial effect in this case can be referred to the application principle of the beneficial effect described above, where the area of ​​the first opening 18 located in the first region 17 is larger than the area of ​​the first opening 18 located in the second region 28, and will not be repeated here.

[0100] For example, the area of ​​the first opening corresponding to different current collector electrodes gradually decreases along the direction from the edge region to the center region. This arrangement helps to ensure that the first opening in the middle of the solar cell has a larger area, thereby allowing for a larger contact area between the current collector electrode and the doped semiconductor layer located at the edge of the cell, reducing carrier recombination. Furthermore, compared to the passivation layer near the edge of the first surface, the passivation layer near the center region is thinner. Setting the first opening near the center region to a relatively small area helps to reduce thermal damage to the doped semiconductor layer below the first opening near the center region, ensuring a high field passivation effect for the doped semiconductor layer.

[0101] Secondly, when the doped semiconductor layer includes N-type doped layers and P-type doped layers that extend along a first direction and are alternately arranged along a second direction, the area of ​​the first opening corresponding to the P-type doped layer can be equal to the area of ​​the first opening corresponding to the N-type doped layer; and / or, the area of ​​the second opening corresponding to the P-type doped layer can be equal to the area of ​​the second opening corresponding to the N-type doped layer.

[0102] Alternatively, the area of ​​at least one first opening on the P-type doped layer may be smaller than the area of ​​at least one first opening on the N-type doped layer; and / or, the area of ​​at least one second opening on the P-type doped layer may be smaller than the area of ​​at least one second opening on the N-type doped layer. In this case, it is advantageous to ensure a larger passivation contact area between the passivation layer and the P-type doped layer, thus preventing the recombination of carriers collected by the P-type doped layer.

[0103] In addition, it is understandable that in the actual manufacturing process, when laser etching is used to set openings in the passivation layer, the different irradiation energy of the laser etching process at the positions corresponding to the first and second openings in the passivation layer will result in different degrees of etching of the passivation layer. Therefore, the irradiation energy corresponding to the laser etching process and the morphology of the passivation layer around the openings after laser etching can be determined based on the size difference between the first and second openings in the edge region and the middle region of the passivation layer.

[0104] For example, such as Figure 6As shown, the passivation layer 13 includes a laser irradiation region 25, which includes a first opening 18, a second opening 19, and laser-affected regions 26 located on the outer periphery of the first opening 18 and the second opening 19, respectively. The passivation layer 13 is disposed within the laser-affected region 26. The thickness of the passivation layer 13 located in the laser-affected region 26 can be less than the thickness of the passivation layer 13 outside the laser irradiation region 25. This configuration, when the thickness of the passivation layer 13 in the laser-affected region 26 is smaller, helps to reduce the residual passivation layer 13 material within the first opening 18 and the second opening 19 inside the laser-affected region 26, ensuring that the current collector electrode 14 can have a larger contact area with the doped semiconductor layer 12 through the first opening 18 and the second opening 19, thus reducing contact resistance. Furthermore, it allows the laser energy to be distributed gradually from the first opening 18 (or the second opening 19) to the laser-affected region 26, making the laser spot easier to control and simplifying the manufacturing process.

[0105] Of course, the thickness of the portion of the passivation layer located in the laser-affected region can also be equal to the thickness of the portion excluding the laser-irradiated region. This configuration improves the passivation effect of the passivation layer around the opening and reduces carrier recombination.

[0106] It should be noted that the range of the laser-affected zone, the first opening, and the second opening can be determined by observing the color differences in different parts of the laser-irradiated area under an electron microscope. Alternatively, since the thickness of the passivation layer at the first and second openings can be zero, while the thickness of the passivation layer in the laser-affected zone is greater than its own thickness at the first and second openings; furthermore, the thickness of the passivation layer in the areas excluding the laser-irradiated zone can be greater than its thickness in the laser-affected zone, therefore, the range of the laser-affected zone, the first opening, and the second opening can also be determined by observing the thickness differences of the passivation layer in different parts of the laser-irradiated area.

[0107] For example, such as Figure 7As shown, the width of the laser-affected region 26 located around the first opening 18 is greater than the width of the laser-affected region 26 located around the second opening 19. With this configuration, during the laser etching process to form the opening by etching the passivation layer 13, the laser spot has higher energy in the center, enabling it to penetrate the passivation layer 13 and form the opening. However, the edge of the laser spot has relatively lower energy and fails to penetrate the passivation layer 13, thus failing to form the laser-affected region 26. In this case, the laser-affected region 26 located around the first opening 18 has a relatively large width. During the actual fabrication process, the laser spot corresponding to the first opening 18 has higher irradiation energy, which facilitates the removal of the thicker passivation layer 13 within the first opening 18 located in the edge region 15. This reduces the amount of passivation layer 13 material remaining in the first opening 18, ensuring sufficient contact area between the current collector electrode 14 and the doped semiconductor layer 12, and reducing carrier recombination in the edge region 15.

[0108] For example, such as Figure 7 As shown, along the second direction, the width of the laser irradiation area 25 around the first opening 18 can be equal to the width of the laser irradiation area 25 around the second opening 19. The length of the laser irradiation area 25 around the first opening 18 along the first direction is greater than the length of the laser irradiation area 25 around the second opening 19 along the first direction. The application principle of the beneficial effect in this case can refer to the application principle of the beneficial effect described above, where the width of the first opening 18 along the second direction is equal to the width of the second opening 19, and the length of the first opening 18 along the first direction is greater than the width of the second opening 19; it will not be repeated here.

[0109] Of course, the area corresponding to the first opening can also be made larger than the area corresponding to the second opening by making the width of the laser irradiation area corresponding to the first opening greater than the width of the laser irradiation area corresponding to the second opening along the second direction.

[0110] For example, such as Figure 6 and Figure 7As shown, the laser irradiation area 25, including the first opening 18, has multiple light spot irradiation sub-areas 27 that partially overlap along a first direction. Along the first direction, the overlap rate of two adjacent light spot irradiation sub-areas 27 within the same laser irradiation area 25 can be greater than or equal to 30% and less than 100%. For example, the overlap rate of two adjacent light spot irradiation sub-areas 27 within the same laser irradiation area 25 can be 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 80%, 90%, or 100%, etc. With this configuration, it can be understood that the laser irradiation energy is higher in the overlapping area of ​​two adjacent laser spots, making it easier to completely remove the passivation layer 13. Based on this, within the same laser irradiation area 25, the overlap rate of two adjacent laser spot irradiation sub-regions 27 is within the aforementioned range. This prevents a small overlap rate from resulting in a larger proportion of areas with lower laser irradiation energy within the first opening 18, leading to a greater amount of residual passivation layer 13 material. This helps ensure sufficient contact area between the current collector electrode 14 and the doped semiconductor layer 12 located in the edge region 15, reducing carrier recombination in the edge region 15. Furthermore, it also prevents damage to the doped semiconductor layer 12 and reduced manufacturing efficiency caused by a large overlap rate, thus ensuring a higher yield for the doped semiconductor layer 12.

[0111] It should be noted that, as Figure 6 and Figure 7 As shown, along the first direction, in the same laser irradiation area 25, both sides of the light spot irradiation sub-area 27 located at the initial position can be exposed outside the adjacent light spot irradiation sub-area 27. The length of the light spot irradiation sub-area 27 along the first direction can be determined based on the distance between the two sides of the light spot irradiation sub-area 27 located at the initial position. Furthermore, in the same laser irradiation area 25, the boundaries of two adjacent light spot irradiation sub-areas 27 located on the same side along the laser travel direction can also be exposed. Determining the distance between these two boundaries allows us to obtain the distance by which the light spot irradiation sub-area 27 corresponding to the later laser irradiation is exposed outside the light spot irradiation sub-area 27 corresponding to the earlier laser irradiation. Based on the length of the light spot irradiation sub-area 27 along the first direction and the distance by which the light spot irradiation sub-area 27 corresponding to the later laser irradiation is exposed outside the light spot irradiation sub-area 27 corresponding to the earlier laser irradiation, the overlap rate of two adjacent light spot irradiation sub-areas 27 in the same laser irradiation area 25 along the first direction can be calculated.

[0112] Furthermore, when the boundary of the light spot irradiation sub-region along the first direction is a straight line, the distance between the two boundaries of the light spot irradiation sub-region at the initial position, and the distance by which the light spot irradiation sub-region corresponding to the subsequent laser irradiation is exposed outside the light spot irradiation sub-region corresponding to the previous laser irradiation, can be obtained by direct measurement. However, when the boundary of the light spot irradiation sub-region along the first direction is a curve or a wavy line, etc., and is not a straight line, the distance between the two boundaries of the light spot irradiation sub-region at the initial position can be determined as follows: a straight line can be drawn along the first direction through both boundaries of the light spot irradiation sub-region at the initial position. This straight line intersects with both boundaries at points, and the length of the line connecting these two intersection points is the distance between the two boundaries of the light spot irradiation sub-region at the initial position.

[0113] When the doped semiconductor layer includes N-type doped layers and P-type doped layers that extend along a first direction and are alternately arranged along a second direction, the overlap rate of two adjacent light spot irradiation sub-regions in the laser irradiation region corresponding to the P-type doped layer, including the first opening, can be equal to the overlap rate of two adjacent light spot irradiation sub-regions in the laser irradiation region corresponding to the N-type doped layer, including the first opening.

[0114] Alternatively, the overlap rate of two adjacent irradiated sub-regions in the laser irradiation region including the first opening of the P-type doped layer can be greater than that of two adjacent irradiated sub-regions in the laser irradiation region including the first opening of the N-type doped layer. With this configuration, as mentioned earlier, the conductivity of the P-type doped layer is poorer than that of the N-type doped layer. Therefore, setting a larger overlap rate in the laser irradiation region including the first opening of the P-type doped layer reduces the proportion of non-overlapping areas in the laser irradiation region, allowing more local areas in the laser irradiation region including the first opening to receive higher laser irradiation energy. This helps ensure that the first opening exposes a portion of the P-type doped layer located below it, and also helps reduce the amount of passivation layer material remaining in the first opening. This provides sufficient contact area between the second current collector and the P-type doped layer, reducing contact resistance and carrier recombination. Simultaneously, it also helps prevent the N-type doped layer from being affected by excessively high-energy laser irradiation, reducing thermal damage to the N-type doped layer.

[0115] For example, within the same laser irradiation area, the minimum distance L between the boundary lines of two adjacent light spot irradiation sub-regions extending along the second direction on the same side is greater than 0 and less than or equal to 50 μm. For instance, the minimum distance L between the boundary lines of two adjacent light spot irradiation sub-regions extending along the second direction on the same side within the same laser irradiation area can be 0.5 μm, 5 μm, 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, 45 μm, or 50 μm, etc. The beneficial effect in this case can be referenced to the previously mentioned overlap rate of two adjacent light spot irradiation sub-regions within the same laser irradiation area that is greater than or equal to 30% and less than or equal to 100%, which will not be elaborated upon here.

[0116] When the doped semiconductor layer includes N-type doped layers and P-type doped layers that extend along a first direction and are alternately arranged along a second direction, the minimum spacing between the boundary lines extending along the second direction in two adjacent light spot irradiation sub-regions in the laser irradiation region corresponding to the P-type doped layer, including the first opening, can be smaller than the minimum spacing between the boundary lines extending along the second direction in two adjacent light spot irradiation sub-regions in the laser irradiation region corresponding to the N-type doped layer, including the first opening. The application principle of this beneficial effect can be referenced to the application principle of the beneficial effect described above, where the overlap rate of two adjacent light spot irradiation sub-regions in the laser irradiation region corresponding to the P-type doped layer, including the first opening, is greater than the overlap rate of two adjacent light spot irradiation sub-regions in the laser irradiation region corresponding to the N-type doped layer, including the first opening; it will not be repeated here.

[0117] Of course, the minimum spacing between the boundary lines extending along the second direction in the laser irradiation region of the P-type doped layer, including the first opening, can also be equal to the minimum spacing between the boundary lines extending along the second direction in the laser irradiation region of the N-type doped layer, including the first opening.

[0118] As for how many collector electrodes are electrically connected to the doped semiconductor layer through the first opening along the second direction, it can be determined based on the width of the edge region in the actual application scenario, the difference in carrier collection requirements between the edge region and the middle region, the deposition and plating of the passivation layer during actual fabrication, the spacing between adjacent collector electrodes, and other actual requirements.

[0119] For example, the number of current collectors electrically connected to the doped semiconductor layer through the first opening can be greater than or equal to 1 and less than or equal to 5. For instance, the number of current collectors electrically connected to the doped semiconductor layer through the first opening (which can be only current collectors of the same polarity, or include current collectors of the same polarity and opposite polarities) can be 1, 2, 3, 4, or 5. In this case, it can prevent a small passivation contact area between the passivation layer and the doped semiconductor layer due to an excessively large number of current collectors electrically connected to the doped semiconductor layer through the first opening, thus ensuring a high passivation effect of the passivation layer on the doped semiconductor layer. Simultaneously, an excessively large number of current collectors electrically connected to the doped semiconductor layer through the first opening means that the middle or near-middle position of the solar cell is also configured with a large first opening area, leading to significant thermal damage to the doped semiconductor layer at the middle or near-middle position of the solar cell. Therefore, setting the number of current collectors electrically connected to the doped semiconductor layer through the first opening to less than or equal to 5 can reduce or even avoid thermal damage to the doped semiconductor layer at the middle or near-middle position of the solar cell.

[0120] Furthermore, when the doped semiconductor layer includes N-type and P-type doped layers extending along a first direction and alternately arranged along a second direction, and the collector electrode includes a first collector electrode and a second collector electrode alternately spaced along the second direction, the number of first collector electrodes electrically connected to the N-type doped layer through the first opening can be equal to the number of second collector electrodes electrically connected to the P-type doped layer through the first opening. Alternatively, the number of first collector electrodes electrically connected to the N-type doped layer through the first opening can be less than the number of second collector electrodes electrically connected to the P-type doped layer through the first opening. In this case, when the number of first collector electrodes electrically connected to the N-type doped layer through the first opening is small, it can prevent thermal damage to the N-type doped layer caused by excessive laser irradiation during etching of the passivation layer on the inner side of the N-type doped layer along the direction from the edge region to the middle region. This ensures a high yield of the N-type doped layer and helps to ensure a large passivation contact area between the passivation layer and the N-type doped layer. In addition, since the conductivity of the P-type doped layer is relatively poor compared to the N-type doped layer, a larger number of second collector electrodes electrically connected to the P-type doped layer through the first opening can ensure sufficient carrier collection contact area between the second collector electrodes and the outer P-type doped layer along the direction from the middle region to the edge region, ensuring the hole collection effect in the edge region.

[0121] The specific number of the first collector electrodes electrically connected to the N-type doped layer through the first opening, and the specific number of the second collector electrodes electrically connected to the P-type doped layer through the first opening, can be determined based on the width of the edge region in the actual application scenario, the spacing between adjacent first and second collector electrodes, the doping concentration of the N-type and P-type doped layers, and actual requirements.

[0122] For example, the number of first collector electrodes electrically connected to the N-type doped layer through the first opening is greater than or equal to 1 and less than or equal to 3. For instance, the number of first collector electrodes electrically connected to the N-type doped layer through the first opening can be 1, 2, or 3.

[0123] For example, the number of second collector electrodes electrically connected to the P-type doped layer through the first opening is greater than or equal to 2 and less than or equal to 5. For instance, the number of second collector electrodes electrically connected to the P-type doped layer through the first opening can be 2, 3, 4, or 5.

[0124] Furthermore, in practical applications, no passivation layer material may remain in any part of the area within the first opening. This arrangement increases the contact area between the current collector electrode and the doped semiconductor layer through the larger first opening, which helps to reduce contact resistance.

[0125] Or, such as Figure 8 and Figure 9 As shown, the edge region within the first opening 18 includes residual material of the passivation layer 13. In this case, the material of the passivation layer 13 located in the edge region within the first opening 18 can passivate the edge region of the first opening 18, compensating for the disadvantage of a smaller passivation contact area between the passivation layer 13 and the doped semiconductor layer 12 due to the larger area corresponding to the first opening 18, thereby reducing carrier recombination in the edge region within the first opening 18. Simultaneously, it also helps protect the doped semiconductor layer 12 beneath the material of the passivation layer 13 located in the edge region within the first opening 18, preventing damage to the doped semiconductor layer 12 and ensuring that the doped semiconductor layer 12 has a high field passivation effect.

[0126] The width of the edge region of the material with the passivation layer remaining in the first opening can be determined based on the area corresponding to the first opening and the requirements for the contact area between the doped semiconductor layer and the collector electrode.

[0127] Furthermore, the portion of the surface of the doped semiconductor layer on the side opposite to the semiconductor substrate within the first opening can be planar.

[0128] Or, such as Figure 10As shown, a protrusion structure 20 can be provided on the surface of the doped semiconductor layer 12 facing away from the semiconductor substrate 11 within the first opening 18. With this configuration, in the actual fabrication process, the passivation layer 13 can be etched using a laser etching process to form the opening. Specifically, during the etching process of the passivation layer 13 corresponding to the opening using a high-temperature laser spot, the doped semiconductor layer 12 below absorbs the laser light, its temperature increases, and its surface melts to form the protrusion structure 20. This increases the surface roughness, which helps to increase the contact area between the doped semiconductor layer 12 and the collector electrode 14, and reduces the contact resistance.

[0129] The shape and size of the protruding structure can be set according to actual needs. For example, the protruding structure can be in the form of a cone or a quasi-conical shape with rounded apex angles.

[0130] When the area corresponding to the first opening is larger than the area corresponding to the second opening, the characteristic parameters of the protrusions on the surface of the edge region within the first opening can be smaller than the characteristic parameters of the protrusions on the surface of the central region within the first opening. The characteristic parameters include at least one of quantity, density, and height. Specifically, the characteristic parameters of the protrusions can be only any one of quantity, density, and height. In this case, it can be only that the number of protrusions on the surface of the edge region within the first opening is less than the number of protrusions on the surface of the central region within the first opening, or only that the density of the protrusions on the surface of the edge region within the first opening is less than the density of the protrusions on the surface of the central region within the first opening, or only that the height of the protrusions on the surface of the edge region within the first opening is less than the height of the protrusions on the surface of the central region within the first opening. Alternatively, the characteristic parameters of the protrusion structure can be at least two of the following: number, density, and height. In this case, the characteristic parameters of the protrusion structure on the edge region surface within the first opening being less than those of the protrusion structure on the central region surface within the first opening means that at least two of the number, density, and height of the protrusion structure on the edge region surface within the first opening are compared with the same values ​​of the number, density, and height of the protrusion structure on the central region surface within the first opening. With this configuration, when the number of protrusion structures on the central region surface within the first opening is large, the surface roughness of the central region of the first opening is greater, which is beneficial for increasing the contact area between the doped semiconductor layer and the collector electrode, and reducing the contact resistance.

[0131] Alternatively, the characteristic parameters of the protrusions on the surface of the edge region within the first opening can be equal to the characteristic parameters of the protrusions on the surface of the central region within the first opening. This configuration helps reduce the residual passivation layer material in the edge region within the first opening and increases the contact area between the current collector electrode and the doped semiconductor layer.

[0132] In this configuration, where the doped semiconductor layer comprises N-type and P-type doped layers extending along a first direction and alternately arranged along a second direction, and a protrusion structure can be provided within the first opening on the surface of the doped semiconductor layer facing away from the semiconductor substrate, the characteristic parameter of the protrusion structure within the first opening corresponding to the N-type doped layer on the edge region of the first surface can be greater than the characteristic parameter of the protrusion structure within the first opening corresponding to the P-type doped layer (the meaning of the characteristic parameter can be found above and will not be repeated here). This configuration, when the characteristic parameter of the protrusion structure within the first opening corresponding to the N-type doped layer is larger, is beneficial for increasing the surface roughness of the N-type doped layer exposed at the first opening, increasing the contact area between the N-type doped layer and the collector electrode, and ensuring higher contact performance between the N-type doped layer and the collector electrode.

[0133] Alternatively, the characteristic parameters of the protrusion structure within the first opening corresponding to the N-type doped layer can also be equal to the characteristic parameters of the protrusion structure within the first opening corresponding to the P-type doped layer.

[0134] For example, along the second direction, the characteristic parameter of the protrusion structure within the first opening corresponding to the first collector electrode away from the edge region can be greater than the characteristic parameter of the protrusion structure within the first opening corresponding to the first collector electrode near the edge region, and / or, the characteristic parameter of the protrusion structure within the first opening corresponding to the second collector electrode away from the edge region is greater than the characteristic parameter of the protrusion structure within the first opening corresponding to the second collector electrode near the edge region. Taking the second collector electrode as an example, in the first surface of the semiconductor substrate, since the central region mainly ensures carrier collection, the characteristic parameter of the protrusion structure within the first opening corresponding to the second collector electrode away from the edge region along the second direction is set to be greater than the characteristic parameter of the protrusion structure within the first opening corresponding to the second collector electrode near the edge region. In this case, it is advantageous to ensure that the surface of the region where the P-type doped layer is exposed in the first opening located on the inner side along the direction from the edge region to the central region has a larger specific surface area, which is beneficial to increasing the contact area between the P-type doped layer and the second collector electrode at this location, ensuring that the carriers collected by the P-type doped layer in the part of the edge region near the central region with higher power generation efficiency can be timely discharged.

[0135] For example, the doped semiconductor layer includes a first doped silicon layer and a second doped silicon layer disposed on at least a portion of the side of the first doped silicon layer facing away from the semiconductor substrate. The crystallinity of the second doped silicon layer is less than that of the first doped silicon layer. As mentioned above, the portion corresponding to the opening of the passivation layer can be etched by irradiation with a high-temperature laser spot. During the etching process, the temperature of the underlying doped semiconductor layer increases after absorbing the laser, and its surface melting also causes a change in its crystal phase (e.g., from polycrystalline to amorphous). Compared with the highly crystallized first doped silicon layer, the less crystallized second doped silicon layer has a relatively higher passivation effect. Therefore, when the doped semiconductor layer also includes a second doped silicon layer, the passivation effect of the doped semiconductor layer on the semiconductor substrate can be improved, and the carrier recombination rate can be reduced.

[0136] In the embodiments of the invention, a higher degree of crystallization can refer to a higher crystallization rate, a larger grain size, and / or a greater number of grains. For example, the first doped silicon layer includes a polycrystalline silicon layer, and the second doped silicon layer includes an amorphous silicon layer (the amorphous silicon layer may contain a small amount of microcrystalline silicon and / or nanocrystalline silicon, but the content of the microcrystalline silicon and / or nanocrystalline silicon is very small, for example, less than 5%, as is known in the art).

[0137] Secondly, such as Figure 11 As shown, the second doped silicon layer 22 can be disposed at least on the portion of the first doped silicon layer 21 corresponding to the opening. Alternatively, the second doped silicon layer can also be disposed on the entire surface of the first doped silicon layer on the side facing away from the semiconductor substrate.

[0138] When the doped semiconductor layer includes a first doped silicon layer and a second doped silicon layer, the thickness of the second doped silicon layer in the edge region within the first opening can be less than the thickness of the second doped silicon layer in the central region within the first opening. With this configuration, the second doped silicon layer with a lower degree of crystallinity has a relatively higher passivation effect compared to the first doped silicon layer with a higher degree of crystallinity. When the thickness of the second doped silicon layer in the central region within the first opening is larger, the passivation effect of the doped semiconductor layer on the semiconductor substrate at the portion corresponding to the first opening can be improved, compensating for the difference in passivation effect between different regions covered by the passivation layer in the first surface caused by passivation layer opening, thereby improving the working performance of the solar cell. Furthermore, a larger distribution of the number of protrusions in the central region within the first opening and / or a larger thickness of the second doped silicon layer indicates a higher degree of irradiation of the portion of the passivation layer corresponding to the central region within the first opening using laser etching. This ensures that there is no residual passivation layer material in the central region within the first opening (or minimizes residual passivation layer material), which is beneficial for improving the contact performance between the current collector electrode and the doped semiconductor layer.

[0139] Alternatively, the thickness of the second doped silicon layer in the edge region within the first opening can also be equal to the thickness of the second doped silicon layer in the central region within the first opening.

[0140] When the doped semiconductor layer includes N-type and P-type doped layers extending along a first direction and alternately arranged along a second direction, and the doped semiconductor layer includes the aforementioned first and second doped silicon layers in the edge region of the first surface, the thickness of the second doped silicon layer within the first opening corresponding to the N-type doped layer in the edge region of the first surface can be greater than the thickness of the second doped silicon layer within the first opening corresponding to the P-type doped layer. The application principle of this beneficial effect can be referenced from the application principle of the beneficial effect of the larger characteristic parameters of the protrusion structure within the first opening corresponding to the N-type doped layer described above, and will not be repeated here.

[0141] Alternatively, the thickness of the second doped silicon layer within the first opening corresponding to the N-type doped layer can also be equal to the thickness of the second doped silicon layer within the first opening corresponding to the P-type doped layer.

[0142] For example, the thickness of the second doped silicon layer within the first opening corresponding to the first collector electrode far from the edge region can be greater than the thickness of the second doped silicon layer within the first opening corresponding to the first collector electrode near the edge region, and / or, the thickness of the second doped silicon layer within the first opening corresponding to the second collector electrode far from the edge region can be greater than the thickness of the second doped silicon layer within the first opening corresponding to the second collector electrode near the edge region. Taking the second collector electrode as an example, as mentioned above, the passivation effect of the second doped silicon layer is higher than that of the first doped silicon layer. Therefore, a larger thickness of the second doped silicon layer within the first opening corresponding to the second collector electrode far from the edge region is beneficial in ensuring that the second doped silicon layer has a very high passivation effect on the portion of the edge region with higher power generation efficiency near the central region, reducing carrier recombination at the inner first opening.

[0143] In addition, in the actual manufacturing process, the thickness of the passivation layer located at the four corners of the first surface can be equal to the thickness of the rest of the passivation layer.

[0144] Alternatively, the thickness of the passivation layer at the four corners of the solar cell can be greater than the thickness of the passivation layer at other locations. In this case, the etching difficulty of the passivation layer at the four corners of the first surface in the edge region may be greater than that of the remaining areas. Therefore, the difference in thickness between the passivation layer at the four corners of the first surface in the edge region and the passivation layer thickness in the remaining areas can be used to determine the area size of the openings in these two types of regions, as well as the morphology of the doped semiconductor layer within the openings and whether there are any passivation layer residues.

[0145] For example, when the doped semiconductor layer includes N-type doped layers and P-type doped layers extending along a first direction and alternately arranged along a second direction, the area of ​​the passivation layer material remaining in the first opening corresponding to the P-type doped layer at the four corners of the solar cell can be larger than the area of ​​the passivation layer material remaining in the first opening corresponding to the N-type doped layer at the four corners of the solar cell. The application principle of this beneficial effect can be referred to the application principle of the beneficial effect of the larger characteristic parameters of the protrusion structure in the first opening corresponding to the N-type doped layer described above, and will not be repeated here.

[0146] Alternatively, the area of ​​the passivation layer material remaining in the first opening corresponding to the P-type doped layer located at the four corners of the solar cell can be equal to the area of ​​the passivation layer material remaining in the first opening corresponding to the N-type doped layer located at the four corners of the solar cell.

[0147] Furthermore, in practical applications, the area of ​​the passivation layer material remaining in the inner edge region of the opening at the four corners of the first surface can be equal to the area of ​​the passivation layer material remaining in the inner edge region of the opening at the other positions on the first surface.

[0148] Alternatively, in the edge region, the area of ​​the passivation layer material remaining in the edge region within the first opening at the four corners of the solar cell can be larger than the area of ​​the passivation layer material remaining in the edge region within the first opening at other locations. This configuration results in a larger area of ​​passivation layer material remaining in the edge region within the openings at the four corners of the first surface, which is beneficial for improving the passivation effect of the passivation layer at these locations and reducing carrier recombination. Furthermore, when the thickness of the passivation layer at the four corners of the first surface is greater than the thickness of the passivation layer at other locations in the edge region, the etching of the passivation layer at the four corners of the first surface using laser etching to form the openings is correspondingly more difficult. Based on this, when the area of ​​the passivation layer material remaining in the edge region of the first opening at the four corners of the first surface is larger, it indicates that when etching the passivation layer at the four corners of the first surface, excessively high energy laser irradiation was not used. This helps to prevent problems such as microcracks or edge breakage caused by high heat loss at the corners of the solar cell, thereby improving the cell yield.

[0149] Secondly, in the edge region of the first surface, when a protrusion structure is provided on the surface of the area exposed at the opening on the side of the doped semiconductor layer away from the semiconductor substrate, the characteristic parameters of the protrusion structure in the first opening located at the corner of the solar cell can be equal to the characteristic parameters of the protrusion structure in the first opening at other locations.

[0150] Alternatively, the characteristic parameters of the protruding structure within the first opening located at a corner of the solar cell can be smaller than the characteristic parameters of the protruding structures within the first opening at other locations. The characteristic parameters include at least one of quantity, density, and height. The beneficial effect in this case can be understood by referring to the previously described principle that the area of ​​the passivation layer material remaining in the edge region of the first opening at the four corners of the first surface is larger than the area of ​​the passivation layer material remaining in the edge region of the first opening at other locations on the first surface; this will not be elaborated upon here.

[0151] In the edge region of the first surface, if the doped semiconductor layer includes the first doped silicon layer and the second doped silicon layer described above, the thickness of the second doped silicon layer in the first opening at the corner of the solar cell can be equal to the thickness of the second doped silicon layer in the first opening at other locations.

[0152] Alternatively, in the edge region, the thickness of the second doped silicon layer within the first opening at the corner of the solar cell is less than the thickness of the second doped silicon layer within the first opening at other locations. The application principle of the beneficial effects in this case can be found above.

[0153] For the collector electrodes, multiple collector electrodes are disposed on the side of the passivation layer away from the doped semiconductor layer. The multiple collector electrodes extend along a first direction and are spaced apart along a second direction. The first and second directions can be any two directions parallel to the first surface and different from each other. Optionally, the first direction is perpendicular to the second direction.

[0154] The embodiments of the present invention do not impose specific limitations on the structure and materials of the current collector electrode, which can be set according to actual needs.

[0155] For example, the current collector includes a seed layer located on the doped semiconductor layer and corresponding to the first opening or the second opening, and a metal layer located on the seed layer, the seed layer being in contact with the doped semiconductor layer through the first opening or the second opening. In this case, the thickness of the seed layer in the edge region within the first opening may be equal to the thickness of the seed layer in the central region within the first opening. And / or, the thickness of the seed layer in the edge region within the second opening may be equal to the thickness of the seed layer in the central region within the second opening.

[0156] Or, such as Figure 12 and Figure 13As shown, the thickness of the seed layer 29 located at the edge region of the first opening 18 can also be greater than the thickness of the seed layer 29 located in the central region of the first opening 18; and / or, the thickness of the seed layer 29 located at the edge region of the second opening 19 can also be greater than the thickness of the seed layer 29 located in the central region of the second opening 19. In this case, during the process of forming the opening by etching the passivation layer 13 using a laser etching process, the energy at the edge of the laser spot is relatively small (compared to the center of the spot), resulting in residual passivation layer 13 material in the edge region 15 inside the opening. Although this residual passivation layer 13 material can improve the passivation effect, it will also hinder the connection between the current collector electrode 14 and the doped semiconductor layer 12. Based on this, taking the first opening 18 as an example: The seed layer 29 located in the edge region within the first opening 18 has a relatively large thickness. This can compensate for the disadvantage of the passivation layer 13 material remaining in the edge region of the first opening 18 hindering carrier transport, thus improving the contact performance between the seed layer 29 and the doped semiconductor layer 12, and consequently improving carrier collection efficiency. Furthermore, while improving edge contact performance, the relatively thick seed layer 29 in the edge region of the first opening 18 can also prevent the upper metal layer from entering the bottom layer from the edge, reducing metal recombination losses and improving contact performance.

[0157] Wherein, when the collector electrode includes a seed layer and a metal layer, and the doped semiconductor layer includes N-type doped layers and P-type doped layers that extend along a first direction and are alternately arranged along a second direction, the difference between the thickness of the seed layer in the inner edge region of the first opening corresponding to the N-type doped layer and the thickness of the seed layer in the middle region can be equal to the difference between the thickness of the seed layer in the inner edge region of the first opening corresponding to the P-type doped layer and the thickness of the seed layer in the middle region; and / or, the difference between the thickness of the seed layer in the inner edge region of the second opening corresponding to the N-type doped layer and the thickness of the seed layer in the middle region can be equal to the difference between the thickness of the seed layer in the inner edge region of the second opening corresponding to the P-type doped layer and the thickness of the seed layer in the middle region.

[0158] Alternatively, the difference between the thickness of the seed layer in the edge region and the thickness of the seed layer in the middle region of the first opening corresponding to the N-type doped layer is less than the difference between the thickness of the seed layer in the edge region and the thickness of the seed layer in the middle region of the first opening corresponding to the P-type doped layer. And / or, the difference between the thickness of the seed layer in the edge region and the thickness of the seed layer in the middle region of the second opening corresponding to the N-type doped layer is less than the difference between the thickness of the seed layer in the edge region and the thickness of the seed layer in the middle region of the second opening corresponding to the P-type doped layer. Taking the first opening as an example, when the difference between the thickness of the seed layer in the edge region and the thickness of the seed layer in the middle region of the first opening corresponding to the N-type doped layer is small, the uniformity of the seed layer thickness in the first opening corresponding to the N-type doped layer is higher. This is beneficial for providing a smoother stress transition at the contact surface between the seed layer and the metal layer, reducing stress accumulation at the contact surface, and avoiding the generation of cracks or gaps. Compared to the N-type doped layer, the P-type doped layer has weaker carrier separation and transport capabilities, requiring reinforcement of the carrier transport channels. Based on this, when the difference between the thickness of the seed layer in the edge region of the first opening corresponding to the P-type doped layer and the thickness of the seed layer in the middle region is large, it is beneficial to increase the surface area of ​​the seed layer, thereby increasing the contact area between the seed layer and the metal layer, reducing the contact resistance, and facilitating the timely extraction of charge carriers.

[0159] For example, the surface roughness of the portion of the N-type doped layer exposed at the first opening can be greater than the surface roughness of the portion of the P-type doped layer exposed at the first opening; and / or, the surface roughness of the portion of the N-type doped layer exposed at the second opening can be greater than the surface roughness of the portion of the P-type doped layer exposed at the second opening. The application principle of the beneficial effect in this case can refer to the application principle of the beneficial effect of the larger characteristic parameter of the protrusion structure in the first opening corresponding to the N-type doped layer described above, which will not be repeated here.

[0160] Secondly, embodiments of the present invention provide a photovoltaic module, which includes 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.

[0161] 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 of the first aspect and its various implementations, and will not be repeated here.

[0162] Thirdly, embodiments of the present invention provide a method for manufacturing a solar cell, the method comprising: First, a semiconductor substrate is provided. The semiconductor substrate includes a first surface and a second surface disposed opposite to each other. The first surface includes two edge regions disposed opposite to each other and extending along a first direction, and a central region located between the two edge regions.

[0163] The material and conductivity type of the semiconductor substrate, as well as the width of the edge and middle regions in the first surface, can be referred to in the previous text and will not be repeated here.

[0164] Next, as Figure 14 As shown, a doped semiconductor layer 12 is formed on the first surface.

[0165] In practical applications, when the doped semiconductor layer is entirely disposed on the first surface, processes such as deposition and doping can be used to form the doped semiconductor layer on the first surface.

[0166] When the doped semiconductor layer is disposed on a local area of ​​the first surface, selective etching of the doped semiconductor layer can be achieved by laser etching, photolithography combined with wet etching, or chemical etching after the entire doped semiconductor layer is formed.

[0167] When the doped semiconductor layer includes P-type doped layers and N-type doped layers spaced apart along a direction parallel to the first surface, the P-type doped layer and N-type doped layer can be formed respectively in the manner described above for forming a doped semiconductor layer locally disposed on the first surface.

[0168] Next, as Figure 15 As shown, a passivation layer 13 can be formed on the side of the doped semiconductor layer 12 away from the semiconductor substrate 11 using processes such as chemical vapor deposition.

[0169] Next, as Figure 16 As shown, an opening is formed on the passivation layer 13.

[0170] In the actual manufacturing process, laser etching can be used to form openings within the passivation layer. The amount of laser energy applied to the passivation layer at different opening locations can be determined based on the size of the opening.

[0171] When an opening located on the edge region is defined as a first opening and an opening located on the central region is defined as a second opening, if the area corresponding to at least one first opening is larger than the area corresponding to the second opening, the irradiation energy of the passivation layer corresponding to the first opening using laser etching can be greater than the irradiation energy of the passivation layer corresponding to the second opening using laser etching. Specifically, the laser spot overlap rate during the etching process of the passivation layer corresponding to the first opening can be greater than the laser spot overlap rate during the etching process of the passivation layer corresponding to the second opening; and / or, the laser irradiation power during the etching process of the passivation layer corresponding to the first opening can be greater than the laser irradiation power during the etching process of the passivation layer corresponding to the second opening.

[0172] For example, forming an opening on the passivation layer may include the steps of: using a laser etching process to overlap m laser spots in the edge region to form a first opening; and using a laser etching process to either irradiate with one laser spot or overlap n laser spots in the central region to form a second opening. Here, m is a positive integer greater than or equal to 2, and n is a positive integer greater than or equal to 2 and less than m. The specific values ​​of M and n can be determined based on the specific dimensions of the first and second openings, as well as the size of the laser spots, and are not specifically limited here.

[0173] Furthermore, when the doped semiconductor layer includes N-type doped layers and P-type doped layers that extend along a first direction and are alternately arranged along a second direction, the laser power used to create the first and second openings at the positions of the passivation layer corresponding to the P-type doped layer using a laser etching process can be equal to the laser power used to create the first and second openings at the positions of the passivation layer corresponding to the N-type doped layer.

[0174] Alternatively, a first and a second opening can be defined by using a laser spot with a first laser power to create a first opening at the location of the passivation layer corresponding to the P-type doped layer. Furthermore, a first and a second opening can be defined by using a laser spot with a second laser power to create a first opening at the location of the passivation layer corresponding to the N-type doped layer. The first laser power can also be different from the second laser power. This configuration helps ensure a larger contact area between the P-type doped layer and the collector electrode, guaranteeing effective hole collection.

[0175] Next, as Figure 17 As shown, multiple collector electrodes 14 can be formed on the side of the passivation layer 13 away from the doped semiconductor layer 12 using processes such as screen printing, electroplating, and electroless plating. The multiple collector electrodes 14 extend along a first direction and are spaced apart along a second direction, the first direction intersecting the second direction. The collector electrodes 14 pass through a first opening 18 and a second opening 19, and are electrically connected to the doped semiconductor layer 12.

[0176] The structure of the collector electrode can be referred to in the previous text, and will not be repeated here.

[0177] 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.

[0178] 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.

[0179] 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, including a first surface and a second surface disposed opposite to each other; A doped semiconductor layer is disposed on the first surface; A passivation layer is provided, covering the side of the doped semiconductor layer opposite to the semiconductor substrate. Multiple collector electrodes are disposed on the side of the passivation layer opposite to the doped semiconductor layer; The plurality of current collectors extend along a first direction and are spaced apart along a second direction, the first direction intersecting the second direction; the passivation layer has an opening, through which the current collectors pass and are electrically connected to the doped semiconductor layer; The first surface includes two edge regions that are disposed opposite to each other and extend along the first direction, and a central region located between the two edge regions; the opening of the passivation layer in the edge region is defined as a first opening, and the opening of the passivation layer in the central region is defined as a second opening; The area of ​​at least one of the first openings is greater than the area of ​​at least one of the second openings.

2. The solar cell according to claim 1, characterized in that, The edge region includes two first regions arranged opposite each other along the first direction, and a second region located between the two first regions; the area of ​​the first opening located in the first region is larger than the area of ​​the first opening located in the second region.

3. The solar cell according to claim 1, characterized in that, The central region includes two third regions arranged opposite each other along the first direction, and a fourth region located between the two third regions; The area of ​​the second opening located in the third region is larger than the area of ​​the second opening located in the fourth region; And / or, the area of ​​the first opening located on the edge region is greater than the area of ​​the second opening located on the fourth region.

4. The solar cell according to claim 1, characterized in that, The doped semiconductor layer includes an N-type doped layer and a P-type doped layer that extend along the first direction and are alternately arranged along the second direction; Wherein, the area of ​​at least one first opening located on the P-type doped layer is smaller than the area of ​​at least one first opening located on the N-type doped layer; And / or, the area of ​​at least one second opening on the P-type doped layer is smaller than the area of ​​at least one second opening on the N-type doped layer.

5. The solar cell according to claim 1, characterized in that, The thickness of the passivation layer located in the edge region is greater than the thickness of the passivation layer located in the central region.

6. The solar cell according to claim 1, characterized in that, The surface of the doped semiconductor layer facing away from the semiconductor substrate has a protrusion structure in the first opening, and the characteristic parameters of the protrusion structure on the edge region surface in the first opening are smaller than the characteristic parameters of the protrusion structure on the middle region surface in the first opening; the characteristic parameters include at least one of number, density and height. And / or, the doped semiconductor layer includes a first doped silicon layer and a second doped silicon layer disposed on at least a portion of the side of the first doped silicon layer facing away from the semiconductor substrate, wherein the crystallization degree of the second doped silicon layer is less than that of the first doped silicon layer, and the thickness of the second doped silicon layer in the edge region of the first opening is less than that in the middle region of the first opening.

7. The solar cell according to claim 1, characterized in that, The edge region within the first opening includes residual material from the passivation layer.

8. The solar cell according to claim 1, characterized in that, Along the second direction, the width of the first opening is equal to the width of the second opening; Along the first direction, the length of the first opening is greater than the length of the second opening.

9. The solar cell according to claim 1, characterized in that, The number of collector electrodes electrically connected to the doped semiconductor layer through the first opening is greater than or equal to 1 and less than or equal to 5.

10. The solar cell according to claim 1, characterized in that, The doped semiconductor layer includes an N-type doped layer and a P-type doped layer that extend along the first direction and are alternately arranged along the second direction; the collector electrode includes a first collector electrode and a second collector electrode that are alternately arranged along the second direction, the first collector electrode being electrically connected to the N-type doped layer, and the second collector electrode being electrically connected to the P-type doped layer. The number of first collector electrodes electrically connected to the N-type doped layer through the first opening is less than the number of second collector electrodes electrically connected to the P-type doped layer through the first opening.

11. The solar cell according to claim 10, characterized in that, The number of the first collector electrodes electrically connected to the N-type doped layer through the first opening is greater than or equal to 1 and less than or equal to 3; And / or, the number of second collector electrodes electrically connected to the P-type doped layer through the first opening is greater than or equal to 2 and less than or equal to 5.

12. The solar cell according to claim 1, characterized in that, The doped semiconductor layer includes an N-type doped layer and a P-type doped layer that extend along the first direction and are alternately arranged along the second direction; the collector electrode includes a first collector electrode and a second collector electrode that are alternately arranged along the second direction, the first collector electrode being electrically connected to the N-type doped layer, and the second collector electrode being electrically connected to the P-type doped layer. In this configuration, both the P-type doped layer and the N-type doped layer have raised structures on their surfaces exposed at the first opening on the side facing away from the semiconductor substrate. Along the second direction, the characteristic parameters of the raised structures within the first opening corresponding to the first collector electrode, which is farther from the edge region, are greater than the characteristic parameters of the raised structures within the first opening corresponding to the first collector electrode, which is closer to the edge region; and / or, the characteristic parameters of the raised structures within the first opening corresponding to the second collector electrode, which is farther from the edge region, are greater than the characteristic parameters of the raised structures within the first opening corresponding to the second collector electrode, which is closer to the edge region. The characteristic parameters include at least one of quantity, density, and height. And / or, both the P-type doped layer and the N-type doped layer include a first doped silicon layer and a second doped silicon layer disposed on at least a portion of the side of the first doped silicon layer facing away from the semiconductor substrate, wherein the crystallization degree of the second doped silicon layer is less than that of the first doped silicon layer; the thickness of the second doped silicon layer in the first opening corresponding to the first collector electrode away from the edge region is greater than the thickness of the second doped silicon layer in the first opening corresponding to the first collector electrode near the edge region, and / or, the thickness of the second doped silicon layer in the first opening corresponding to the second collector electrode away from the edge region is greater than the thickness of the second doped silicon layer in the first opening corresponding to the second collector electrode near the edge region.

13. The solar cell according to claim 1, characterized in that, The passivation layer includes a laser irradiation area, which includes a first opening, a second opening, and laser-affected areas located on the outer periphery of the first opening and the outer periphery of the second opening, respectively. The passivation layer is disposed within the laser-affected area; the thickness of the passivation layer located in the laser-affected area is less than the thickness of the passivation layer outside the laser-irradiated area. And / or, the width of the laser-affected zone located on the outer periphery of the first opening is greater than the width of the laser-affected zone located on the outer periphery of the second opening.

14. The solar cell according to claim 13, characterized in that, Along the second direction, the width of the laser irradiation area on the outer periphery of the first opening is equal to the width of the laser irradiation area on the outer periphery of the second opening; The length of the laser irradiation area on the outer periphery of the first opening along the first direction is greater than the length of the laser irradiation area on the outer periphery of the second opening along the first direction.

15. The solar cell according to claim 13, characterized in that, The laser irradiation area including the first opening has multiple light spot irradiation sub-areas that partially overlap along a first direction; Wherein, along the first direction, in the same laser irradiation area, the overlap rate of two adjacent laser spot irradiation sub-areas is greater than or equal to 30% and less than 100%; And / or, within the same laser irradiation area, the minimum distance between the boundary lines of the same side extending along the second direction of two adjacent laser spot irradiation sub-areas is greater than 0 and less than or equal to 50 μm.

16. The solar cell according to claim 1, characterized in that, The doped semiconductor layer includes an N-type doped layer and a P-type doped layer that extend along the first direction and are alternately arranged along the second direction; the passivation layer includes a laser irradiation region, which includes a first opening, a second opening, and laser-affected regions located at the outer periphery of the first opening and the outer periphery of the second opening, respectively; the laser irradiation region has a plurality of light spot irradiation sub-regions that partially overlap along the first direction. Wherein, the overlap rate of two adjacent light spot irradiation sub-regions in the laser irradiation region including the first opening corresponding to the P-type doped layer is greater than the overlap rate of two adjacent light spot irradiation sub-regions in the laser irradiation region including the first opening corresponding to the N-type doped layer. And / or, the minimum spacing between the boundary lines extending along the second direction in two adjacent light spot irradiation sub-regions in the laser irradiation region corresponding to the P-type doped layer, including the first opening, is less than the minimum spacing between the boundary lines extending along the second direction in two adjacent light spot irradiation sub-regions in the laser irradiation region corresponding to the N-type doped layer, including the first opening.

17. The solar cell according to claim 1, characterized in that, The thickness of the passivation layer located at the four corners of the solar cell is greater than the thickness of the passivation layer located at other corners.

18. The solar cell according to claim 1 or 17, characterized in that, In the edge region, the area of ​​the passivation layer material remaining in the edge region within the first opening located at the four corners of the solar cell is greater than the area of ​​the passivation layer material remaining in the edge region within the first opening located at other positions. And / or, in the edge region, a protrusion structure is provided on the surface of the doped semiconductor layer on the side opposite to the semiconductor substrate that is exposed at the first opening, and the characteristic parameter of the protrusion structure in the first opening at the corner position of the solar cell is smaller than the characteristic parameter of the protrusion structure in the first opening at other positions; the characteristic parameter includes at least one of number, density and height; And / or, the doped semiconductor layer includes a first doped silicon layer and a second doped silicon layer disposed on at least a portion of the side of the first doped silicon layer facing away from the semiconductor substrate, wherein the crystallization degree of the second doped silicon layer is less than that of the first doped silicon layer; in the edge region, the thickness of the second doped silicon layer in the first opening located at the corner of the solar cell is less than the thickness of the second doped silicon layer in the first opening at other locations.

19. The solar cell according to claim 1, characterized in that, The doped semiconductor layer includes an N-type doped layer and a P-type doped layer that extend along the first direction and are alternately arranged along the second direction; Wherein, on the edge region, the surface of the doped semiconductor layer facing away from the semiconductor substrate has a protrusion structure within the first opening; on the edge region of the first surface, the characteristic parameter of the protrusion structure within the first opening corresponding to the N-type doped layer is greater than the characteristic parameter of the protrusion structure within the first opening corresponding to the P-type doped layer; the characteristic parameter includes at least one of quantity, density, and height. And / or, both the N-type doped layer and the P-type doped layer include a first doped silicon layer and a second doped silicon layer disposed on at least a portion of the side of the first doped silicon layer facing away from the semiconductor substrate, wherein the crystallization degree of the second doped silicon layer is less than that of the first doped silicon layer; and on the edge region of the first surface, the thickness of the second doped silicon layer in the first opening corresponding to the N-type doped layer is greater than the thickness of the second doped silicon layer in the first opening corresponding to the P-type doped layer. And / or, the area of ​​the passivation layer material remaining in the first opening corresponding to the P-type doped layer located at the four corners of the solar cell is greater than the area of ​​the passivation layer material remaining in the first opening corresponding to the N-type doped layer located at the four corners of the solar cell.

20. The solar cell according to claim 1, characterized in that, The current collector electrode includes a seed layer located on the doped semiconductor layer and corresponding to the first opening or the second opening, and a metal layer located on the seed layer. The seed layer is in contact with the doped semiconductor layer through the first opening or the second opening. Wherein, the thickness of the seed layer located in the edge region of the first opening is greater than the thickness of the seed layer located in the middle region of the first opening; and / or, the thickness of the seed layer located in the edge region of the second opening is greater than the thickness of the seed layer located in the middle region of the second opening.

21. The solar cell according to claim 20, characterized in that, The doped semiconductor layer includes an N-type doped layer and a P-type doped layer that extend along the first direction and are alternately arranged along the second direction; Wherein, the difference between the thickness of the seed layer in the edge region of the first opening corresponding to the N-type doped layer and the thickness of the seed layer in the middle region is less than the difference between the thickness of the seed layer in the edge region of the first opening corresponding to the P-type doped layer and the thickness of the seed layer in the middle region. And / or, the difference between the thickness of the seed layer in the edge region of the second opening corresponding to the N-type doped layer and the thickness of the seed layer in the middle region is less than the difference between the thickness of the seed layer in the edge region of the second opening corresponding to the P-type doped layer and the thickness of the seed layer in the middle region; And / or, the surface roughness of the portion of the N-type doped layer exposed in the first opening is greater than the surface roughness of the portion of the P-type doped layer exposed in the first opening; And / or, the surface roughness of the portion of the N-type doped layer exposed in the second opening is greater than the surface roughness of the portion of the P-type doped layer exposed in the second opening.

22. 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 21; And an encapsulation layer that covers the surface of the battery string.

23. A method for manufacturing a solar cell, characterized in that, include: Provide a semiconductor substrate; The semiconductor substrate includes a first surface and a second surface disposed opposite to each other; the first surface includes two edge regions disposed opposite to each other and extending along a first direction, and a central region located between the two edge regions; A doped semiconductor layer formed on the first surface; A passivation layer is formed on the side of the doped semiconductor layer opposite to the semiconductor substrate; An opening is formed in the passivation layer; The opening of the passivation layer located in the edge region is defined as a first opening, and the opening of the passivation layer located in the middle region is defined as a second opening; The area of ​​at least one of the first openings is greater than the area of ​​at least one of the second openings; Multiple collector electrodes are formed on the side of the passivation layer opposite to the doped semiconductor layer; The plurality of current collector electrodes extend along the first direction and are spaced apart along the second direction, wherein the first direction intersects the second direction; The current collector electrode passes through the first opening and the second opening and is electrically connected to the doped semiconductor layer.

24. The method for manufacturing a solar cell according to claim 23, characterized in that, Forming the opening on the passivation layer includes: The first opening is formed by using a laser etching process and overlapping m laser spots in the edge region; m is a positive integer greater than or equal to 2. The second opening is formed by using a laser etching process, with one laser spot irradiating or n laser spots overlapping in the central region; n is a positive integer greater than or equal to 2 and less than m.

25. The method for manufacturing a solar cell according to claim 23, characterized in that, The doped semiconductor layer includes an N-type doped layer and a P-type doped layer that extend along the first direction and are alternately arranged along the second direction; A laser etching process is used, and the first opening and the second opening are formed at the position of the passivation layer corresponding to the P-type doped layer through a laser spot with a first laser power; A laser etching process is used, and the first opening and the second opening are made at the position of the passivation layer corresponding to the N-type doped layer through a laser spot with a second laser power; the first laser power is different from the second laser power.

Images