Solar cell, manufacturing method thereof and photovoltaic module

Abstract

The invention relates to a solar cell, a manufacturing method thereof and a photovoltaic module, and the manufacturing method of the solar cell comprises the steps: providing a silicon wafer with a suede structure; a first film layer is formed on the side, where the suede structure is located, of the silicon wafer, the first film layer covers the surface of the suede structure, the first film layer comprises a first sub-part located at the bottom of a groove of the suede structure and a second sub-part located outside the bottom of the groove of the suede structure, and the thickness of the first sub-part is larger than that of the second sub-part; and etching the first sub-part at the bottom of the groove of the suede structure so as to reduce the thickness of the first sub-part. Therefore, a good suede structure can be formed on the surface of the side, away from the silicon wafer, of the first film layer, reflection of photons by the surface of the side, away from the silicon wafer, of the first film layer can be reduced, and the conversion efficiency of the solar cell can be improved.

Description

Technical Field

[0001] The present application relates to the field of photovoltaic cell technology, and in particular to solar cells and methods for making same, and photovoltaic modules. Background Art

[0002] Solar cells, also known as photovoltaic cells, are semiconductor devices that convert sunlight directly into electrical energy. As they are green and environmentally friendly products that do not cause environmental pollution, and solar energy is a renewable resource, solar cells are a new type of battery with broad development prospects.

[0003] Crystalline silicon cells are the mainstream cells in solar cells. In order to improve the photon utilization rate of solar cells, the surface of the silicon wafer of the solar cell is usually provided with a pyramid velvet structure. The pyramid velvet structure can reduce the reflection of photons, so that more photons are absorbed and utilized by the solar cell, and the conversion efficiency of the solar cell is improved. However, the production of other film layers on the side of the silicon wafer where the pyramid velvet structure is located will increase the reflection of photons on the side of the silicon wafer where the pyramid velvet structure is located, resulting in a decrease in the conversion efficiency of the solar cell. Summary of the invention

[0004] Based on this, the present application provides a solar cell and a manufacturing method thereof and a photovoltaic module to improve the conversion efficiency of the solar cell.

[0005] An embodiment of the first aspect of the present application provides a method for manufacturing a solar cell, comprising:

[0006] Providing a silicon wafer with a velvet structure;

[0007] Forming a first film layer on the side of the silicon wafer where the velvet structure is located, the first film layer covers the surface of the velvet structure, the first film layer includes a first sub-portion located at the bottom of the groove of the velvet structure and a second sub-portion located outside the bottom of the groove of the velvet structure, and the thickness of the first sub-portion is greater than the thickness of the second sub-portion;

[0008] The first sub-portion located at the bottom of the groove of the texture structure is etched to reduce the thickness of the first sub-portion.

[0009] In some embodiments, the step of etching the first sub-portion located at the bottom of the groove of the velvet structure to reduce the thickness of the first sub-portion includes:

[0010] Putting the silicon wafer in the etching liquid and then pulling it out, so that the etching liquid remains on both the first sub-part and the second sub-part;

[0011] The silicon wafer that has been exposed to the etching liquid is subjected to a first drying treatment to remove the etching liquid on the second sub-part and leave the etching liquid on the first sub-part; the etching liquid on the first sub-part etches the first sub-part to reduce the thickness of the first sub-part.

[0012] In some embodiments, the step of placing the silicon wafer in the etching solution and then pulling it out so that the etching solution remains on both the first sub-section and the second sub-section includes:

[0013] Place the silicon wafer with the textured structure facing upward in a slow pull tank filled with etching solution; the slow pull time is 2s to 6s, and the temperature is 45°C to 65°C.

[0014] In some embodiments, the step of performing a first drying treatment on the silicon wafer that has been subjected to the etching liquid so that the etching liquid on the second sub-portion is removed and the etching liquid remains on the first sub-portion; and etching the first sub-portion with the etching liquid on the first sub-portion so that the thickness of the first sub-portion is reduced comprises:

[0015] The silicon wafer that has been etched by the etching liquid is placed in a drying tank for drying. The first drying time is 3s to 6s, and the first drying temperature is 55°C to 75°C, so that the etching liquid on the second sub-part is removed and the etching liquid remains on the first sub-part; the etching liquid on the first sub-part etches the first sub-part, so that the thickness of the first sub-part is thinned.

[0016] In some embodiments, after the step of performing a first drying treatment on the silicon wafer that has been subjected to the etching liquid so that the etching liquid on the second sub-section is removed and etching liquid remains on the first sub-section; and etching the first sub-section with the etching liquid on the first sub-section so that the thickness of the first sub-section is reduced, the method further comprises:

[0017] The silicon wafer is subjected to a first cleaning treatment to remove the etching liquid on the first sub-portion and the portion of the first sub-portion etched by the etching liquid.

[0018] In some embodiments, a first preset time period is provided between the first drying process and the first cleaning process, and the first preset time period is 8s-15s.

[0019] In some embodiments, the step of performing a first cleaning treatment on the silicon wafer to remove the etching solution on the first sub-portion and the portion of the first sub-portion etched by the etching solution includes:

[0020] The silicon wafer is placed in a first cleaning tank, and the first cleaning time is 55s to 75s.

[0021] In some embodiments, after the step of performing a first cleaning process on the silicon wafer to remove the etching solution on the first sub-portion and the portion of the first sub-portion etched by the etching solution, the method further includes:

[0022] The silicon wafer is subjected to a second drying process.

[0023] In some embodiments, in the second drying process, the second drying time is 350s to 450s, and the second drying temperature is 75°C to 95°C.

[0024] In some embodiments, the first film layer is a doped semiconductor film layer or a passivation anti-reflection film layer; the doped semiconductor film layer is a doped polycrystalline silicon layer, a doped amorphous silicon layer, a doped microcrystalline silicon layer or a doped nanocrystalline silicon layer.

[0025] An embodiment of the second aspect of the present application provides a solar cell, which is manufactured using the solar cell manufacturing method described in any of the above embodiments.

[0026] An embodiment of the third aspect of the present application provides a photovoltaic assembly, comprising the solar cell described in any of the above embodiments.

[0027] In the above-mentioned method for manufacturing a solar cell, the first film layer covering the velvet structure surface of the silicon wafer includes a first sub-portion and a second sub-portion, the first sub-portion is located at the bottom of the groove of the velvet structure, and the second sub-portion is located outside the bottom of the groove of the velvet structure, the thickness of the first sub-portion is greater than the thickness of the second sub-portion, and the thickness of the first sub-portion is reduced by etching the first sub-portion located at the bottom of the groove of the velvet structure. In this way, a better velvet structure can be formed on the surface of the first film layer facing away from the silicon wafer, and even the surface of the first film layer facing away from the silicon wafer can be conformal to the velvet structure on the silicon wafer. As a result, the reflection of photons by the surface of the first film layer facing away from the silicon wafer can be reduced, that is, the reflectivity can be reduced, thereby improving the light utilization rate of the solar cell and improving the conversion efficiency of the solar cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] FIG. 1 is a flow chart of a method for manufacturing a solar cell in some embodiments of the present application.

[0029] FIG. 2 is a flow chart of a method for manufacturing a solar cell in some other embodiments of the present application.

[0030] FIG. 3 is a process flow chart of a method for manufacturing a solar cell in some embodiments of the present application.

[0031] Description of reference numerals:

[0032] 11. Silicon wafer; 111. Velvet structure; 12. First film layer; 121. First sub-unit; 122. Second sub-unit. DETAILED DESCRIPTION

[0033] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present application, so the present application is not limited by the specific embodiments disclosed below.

[0034] In the description of the present application, it should be understood that if the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. appear, the orientation or position relationship indicated by these terms is based on the orientation or position relationship shown in the accompanying drawings, which is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application.

[0035] In addition, if the terms "first" or "second" appear, these terms are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of this application, if the term "plurality" appears, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0036] In this application, unless otherwise clearly specified and limited, if the terms "installed", "connected", "connected", "fixed" and the like appear, these terms should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integrated connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to the specific circumstances.

[0037] In the present application, unless otherwise clearly specified and limited, if there is a description that a first feature is "above" or "below" a second feature, etc., or similar descriptions appear, it may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature being "above", "above" and "above" the second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. The first feature being "below", "below" and "below" the second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0038] It should be noted that if an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be a central element. If an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. If any, the terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used in this application are for illustrative purposes only and do not represent the only implementation method.

[0039] Solar cells, also known as photovoltaic cells, are semiconductor devices that convert sunlight directly into electrical energy. As they are green and environmentally friendly products that do not cause environmental pollution, and solar energy is a renewable resource, solar cells are a new type of battery with broad development prospects.

[0040] Crystalline silicon cells are the mainstream cells in solar cells. In order to improve the photon utilization rate of solar cells, the surface of the silicon wafer of the solar cell is usually provided with a pyramid velvet structure. The pyramid velvet structure can reduce the reflection of photons, so that more photons are absorbed and utilized by the solar cell, and the conversion efficiency of the solar cell is improved. However, the production of other film layers on the side of the silicon wafer where the pyramid velvet structure is located will increase the reflection of photons on the side of the silicon wafer where the pyramid velvet structure is located, resulting in a decrease in the conversion efficiency of the solar cell.

[0041] Based on the above technical problems, the present application provides a solar cell and a manufacturing method thereof and a photovoltaic module to improve the conversion efficiency of the solar cell.

[0042] Referring to FIG. 1 , in a first aspect, an embodiment of the present application provides a method for manufacturing a solar cell, comprising:

[0043] S10, providing a silicon wafer 11 with a velvet structure 111;

[0044] Specifically, for a single-sided solar cell, a velvet structure 111 may be formed on the light-receiving surface of the silicon wafer 11; for a double-sided solar cell, velvet structures 111 are formed on both opposite sides of the silicon wafer 11. The velvet structure 111 may be a pyramid velvet structure.

[0045] S20, forming a first film layer 12 on the side of the velvet structure 111 of the silicon wafer 11, the first film layer 12 covering the surface of the velvet structure 111, the first film layer 12 including a first sub-portion 121 located at the bottom of the groove of the velvet structure 111 and a second sub-portion 122 located outside the bottom of the groove of the velvet structure 111, the thickness of the first sub-portion 121 being greater than the thickness of the second sub-portion 122;

[0046] Specifically, the first film layer 12 may be formed by depositing the first film layer 12 on the side of the silicon wafer 11 where the textured structure 111 is located by using low pressure chemical vapor deposition (LPCVD), plasma enhanced chemical vapor deposition (PECVD) or physical vapor deposition (PVD).

[0047] Due to the height difference between the top of the velvet structure 111 and the bottom of the groove of the velvet structure 111, there is always a height difference between the surface of the first sub-section 121 facing away from the silicon wafer 11 and the surface of the second sub-section 122 facing away from the silicon wafer 11; and due to the unevenness of the surface of the velvet structure 111, the deposition rate of the first film layer 12 material at the bottom of the groove of the velvet structure 111 is greater than the deposition rate of the first film layer 12 material outside the bottom of the groove of the velvet structure 111, which makes the thickness of the first sub-section 121 greater than the thickness of the second sub-section 122, and the height difference between the surface of the first sub-section 121 facing away from the silicon wafer 11 and the surface of the second sub-section 122 facing away from the silicon wafer 11 is reduced, so that the reflectivity of the surface of the first film layer 12 facing away from the silicon wafer 11 is increased.

[0048] S30, etching the first sub-portion 121 at the bottom of the groove of the velvet structure 111 to reduce the thickness of the first sub-portion 121, specifically, the thickness of each part of the first film layer 12 can be made substantially uniform. In this way, the height difference between the surface of the first sub-portion 121 facing away from the silicon wafer 11 and the surface of the second sub-portion 122 facing away from the silicon wafer 11 can be increased, so that the surface of the first film layer 12 facing away from the silicon wafer 11 forms a better velvet structure, thereby reducing the reflection of photons on the surface of the first film layer 12 facing away from the silicon wafer 11, reducing the reflectivity, and improving the utilization rate of photons by the solar cell, thereby improving the conversion efficiency of the solar cell.

[0049] In summary, the manufacturing method of the solar cell provided by the embodiment of the present application, the first film layer 12 covering the surface of the velvet structure 111 of the silicon wafer 11 includes a first sub-portion 121 and a second sub-portion 122, the first sub-portion 121 is located at the bottom of the groove of the velvet structure 111, and the second sub-portion 122 is located outside the bottom of the groove of the velvet structure 111, the thickness of the first sub-portion 121 is greater than the thickness of the second sub-portion 122, and the thickness of the first sub-portion 121 located at the bottom of the groove of the velvet structure 111 is reduced by etching the first sub-portion 121 located at the bottom of the groove of the velvet structure 111, so that the thickness of the first sub-portion 121 is thinned, so that the surface of the first film layer 12 facing away from the silicon wafer 11 can form a better velvet structure, thereby reducing the reflection of photons on the surface of the first film layer 12 facing away from the silicon wafer 11, that is, reducing the reflectivity, thereby improving the light utilization rate of the solar cell and improving the conversion efficiency of the solar cell.

[0050] It should be noted that the first film layer 12 refers to the film layer required for realizing photoelectric conversion in the solar cell; for different types of solar cells, the type of the first film layer 12 is different. For example, for a tunneling oxide layer passivation contact cell, the first film layer 12 can be a doped polycrystalline silicon layer or a passivation anti-reflection layer. For a heterojunction solar cell, the first film layer 12 can be a doped amorphous silicon layer, a doped microcrystalline silicon layer or a doped nanocrystalline silicon layer.

[0051] Referring to FIG. 2 and FIG. 3 , in some embodiments, S30, etching the first sub-portion 121 at the bottom of the groove of the velvet structure 111 to reduce the thickness of the first sub-portion 121, specifically includes:

[0052] S310, placing the silicon wafer 11 in the etching liquid and then pulling it out, so that the etching liquid remains on both the first sub-portion 121 and the second sub-portion 122;

[0053] S320, performing a first drying treatment on the silicon wafer 11 that has been exposed to the etching liquid, so that the etching liquid on the second sub-portion 122 is removed and etching liquid remains on the first sub-portion 121; the etching liquid on the first sub-portion 121 etches the first sub-portion 121, so that the thickness of the first sub-portion 121 is reduced.

[0054] In the above process, the silicon wafer 11 is placed in the etching liquid and then pulled out, and the silicon wafer 11 that has passed through the etching liquid is subjected to a first drying treatment to remove the etching liquid on the second sub-portion 122, so that the second sub-portion 122 can be prevented from being corroded by the etching liquid, thereby ensuring the thickness of the second sub-portion 122; the etching liquid on the first sub-portion 121 is retained, and the etching liquid on the first sub-portion 121 etches the first sub-portion 121, so that the thickness of the first sub-portion 121 is thinned, so that the surface of the first film layer 12 facing away from the silicon wafer 11 can form a better velvet structure, thereby reducing the reflection of photons on the surface of the first film layer 12 facing away from the silicon wafer 11, thereby improving the light absorption capacity of the solar cell, and further improving the open circuit voltage and conversion efficiency of the solar cell.

[0055] In some embodiments, S310, placing the silicon wafer 11 in an etching solution and then pulling it out, so that the etching solution remains on both the first sub-portion 121 and the second sub-portion 122, specifically includes:

[0056] The silicon wafer 11 is placed in a slow pull tank filled with etching solution with the textured structure 111 facing upward; the slow pull time is 2s to 6s, and the temperature is 45°C to 65°C.

[0057] Since the surface of the first sub-section 121 facing away from the silicon wafer 11 is lower than the surface of the second sub-section 122 facing away from the silicon wafer 11, by placing the velvet structure 111 of the silicon wafer 11 facing upward in a slow pulling tank filled with etching solution, the slow pulling time is 2s to 6s, and the temperature is 45°C to 65°C. In this way, more etching solution can be left on the first sub-section 121, and less etching solution can be left on the second sub-section 122. Therefore, after the silicon wafer 11 undergoes the first drying treatment, the etching solution on the second sub-section 122 is removed, and the etching solution still remains on the first sub-section 121, so that the etching solution on the first sub-section 121 can be conveniently used to etch the first sub-section 121, so that the thickness of the first sub-section 121 is thinned, thereby reducing the reflection of photons by the surface of the first film layer 12 facing away from the silicon wafer 11, thereby improving the open circuit voltage and conversion efficiency of the solar cell.

[0058] In some embodiments, S320, performing a first drying process on the silicon wafer 11 after being etched by the etching liquid, so that the etching liquid on the second sub-portion 122 is removed, and the etching liquid remains on the first sub-portion 121; the etching liquid on the first sub-portion 121 etches the first sub-portion 121, so that the thickness of the first sub-portion 121 is reduced, specifically including:

[0059] The silicon wafer 11 that has been etched by the etching liquid is placed in a drying tank for drying. The first drying time is 3s to 6s, and the first drying temperature is 55°C to 75°C, so that the etching liquid on the second sub-section 122 is removed, and the etching liquid remains on the first sub-section 121. The etching liquid on the first sub-section 121 etches the first sub-section 121, so that the thickness of the first sub-section 121 is thinned.

[0060] In the above process, the silicon wafer 11 that has been exposed to the etching liquid is placed in a drying tank for drying, and the first drying time is controlled to be 3s to 6s, and the first drying temperature is 55°C to 75°C, so as to control the degree of drying of the silicon wafer 11, so that etching liquid remains on the first sub-portion 121, and the etching liquid on the second sub-portion 122 is removed, so that the first sub-portion 121 is etched with the etching liquid remaining on the first sub-portion 121, so that the thickness of the first sub-portion 121 is reduced, and the second sub-portion 122 is prevented from being etched, and the thickness of the second sub-portion 122 is ensured. In this way, the surface of the first film layer 12 facing away from the silicon wafer 11 can form a better velvet surface, thereby reducing the reflection of photons on the surface of the first film layer 12 facing away from the silicon wafer 11, that is, reducing the reflectivity, thereby improving the light utilization rate of the solar cell and improving the conversion efficiency of the solar cell.

[0061] 2 and 3 , in some embodiments, S320, the silicon wafer 11 after being etched by the etching liquid is subjected to a first drying process so that the etching liquid on the second sub-portion 122 is removed and the etching liquid remains on the first sub-portion 121; the etching liquid on the first sub-portion 121 etches the first sub-portion 121 so that the thickness of the first sub-portion 121 is reduced, and the method further includes:

[0062] S330 , performing a first cleaning process on the silicon wafer 11 to remove the etching solution on the first sub-portion 121 and the portion of the first sub-portion 121 etched by the etching solution.

[0063] In the above process, the etching solution of the first sub-portion 121 and the etched portion of the first sub-portion 121 can be removed by performing a first cleaning treatment on the silicon wafer 11, thereby reducing the thickness of the first sub-portion 121 and avoiding over-etching of the first sub-portion 121, thereby improving the light absorption capacity of the solar cell and improving the conversion efficiency of the solar cell.

[0064] In some embodiments, S330, performing a first cleaning process on the silicon wafer 11 to remove the etching solution on the first sub-portion 121 and the portion of the first sub-portion 121 etched by the etching solution, specifically includes:

[0065] The silicon wafer 11 is placed in a first cleaning tank, and the first cleaning time is 55s to 75s.

[0066] Specifically, deionized water can be used to clean the silicon wafer 11 in the first cleaning tank, and the first cleaning time is 55s to 75s. In this way, the etching solution on the first sub-portion 121 and the etched portion of the first sub-portion 121 can be removed. At the same time, other ions on the silicon wafer 11 can be removed to prevent the ions of the silicon wafer 11 from entering the subsequent process with the silicon wafer 11, thereby facilitating the sustainability of mass production of solar cells, improving the production efficiency of solar cells, and reducing production costs.

[0067] In some embodiments, a first preset time period is provided between the first drying process and the first cleaning process, and the first preset time period is 8s to 15s.

[0068] Specifically, the time taken for the silicon wafer 11 to be transferred from the drying tank to the first cleaning tank can be controlled to be a first preset time. In this way, the etching liquid on the first sub-portion 121 can etch the first sub-portion 121 within the first preset time. As a result, not only can the thickness of the first sub-portion 121 be reduced and the conversion efficiency of the solar cell be improved, but it also will not affect the manufacturing process and time required for the solar cell, which is beneficial to improving the manufacturing efficiency of the solar cell.

[0069] Referring to FIG. 2 , in some embodiments, after S330, performing a first cleaning process on the silicon wafer 11 to remove the etching solution on the first sub-portion 121 and the portion of the first sub-portion 121 etched by the etching solution, the process further includes:

[0070] S340 , performing a second drying process on the silicon wafer 11 .

[0071] Specifically, in the second drying process, the second drying time is 350s to 450s, and the second drying temperature is 75°C to 95°C.

[0072] In the above process, the silicon wafer 11 is subjected to a second drying treatment, the second drying time is 350s to 450s, and the second drying temperature is 75°C to 95°C to ensure that the silicon wafer 11 and the first film layer 12 are fully dried, which is beneficial to the production of subsequent film layers of solar cells and improves the production efficiency of solar cells.

[0073] In a second aspect, an embodiment of the present application provides a solar cell, which is manufactured using the method for manufacturing a solar cell described in any of the above embodiments, thereby improving the light utilization rate of the solar cell and the conversion efficiency of the solar cell.

[0074] It should be noted that solar cells may include interdigitated back contact cells (IBC), HJT cells (Heterojunction with Intrinsic Thin film), TOPCon cells (Tunnel Oxide Passivated Contact), MWT cells (Metallization wrapthrough), PERC cells (Passivated Emitter and Rear Cell), etc.

[0075] In a third aspect, an embodiment of the present application provides a photovoltaic module, comprising the solar cell in any of the above embodiments, thereby improving the conversion efficiency of the photovoltaic module.

[0076] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0077] The above embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the patent application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent application shall be subject to the attached claims.

Claims

1. A method for manufacturing a solar cell, characterized in that: include: Providing a silicon wafer with a velvet structure; Forming a first film layer on the side of the silicon wafer where the velvet structure is located, the first film layer covers the surface of the velvet structure, the first film layer includes a first sub-portion located at the bottom of the groove of the velvet structure and a second sub-portion located outside the bottom of the groove of the velvet structure, and the thickness of the first sub-portion is greater than the thickness of the second sub-portion; The first sub-portion located at the bottom of the groove of the texture structure is etched to reduce the thickness of the first sub-portion.

2. The method for manufacturing a solar cell according to claim 1, characterized in that: The step of etching the first sub-portion located at the bottom of the groove of the velvet structure to reduce the thickness of the first sub-portion includes: Putting the silicon wafer in the etching liquid and then pulling it out, so that the etching liquid remains on both the first sub-part and the second sub-part; The silicon wafer that has been exposed to the etching liquid is subjected to a first drying treatment, so that the etching liquid on the second sub-section is removed and etching liquid remains on the first sub-section; the etching liquid on the first sub-section etches the first sub-section, so that the thickness of the first sub-section is reduced.

3. The method for manufacturing a solar cell according to claim 2, characterized in that: The step of placing the silicon wafer in the etching liquid and then pulling it out so that the etching liquid remains on both the first sub-part and the second sub-part comprises: Place the silicon wafer with the textured structure facing upward in a slow pull tank filled with etching solution; the slow pull time is 2s to 6s, and the temperature is 45°C to 65°C.

4. The method for manufacturing a solar cell according to claim 2, characterized in that: The step of performing a first drying treatment on the silicon wafer that has been subjected to the etching liquid to remove the etching liquid on the second sub-section and leaving etching liquid on the first sub-section; and etching the first sub-section with the etching liquid on the first sub-section to reduce the thickness of the first sub-section comprises: The silicon wafer that has been etched by the etching liquid is placed in a drying tank for drying. The first drying time is 3s to 6s, and the first drying temperature is 55°C to 75°C, so that the etching liquid on the second sub-part is removed, and the etching liquid remains on the first sub-part. The etching liquid on the first sub-part etches the first sub-part, so that the thickness of the first sub-part is thinned.

5. The method for manufacturing a solar cell according to claim 2, characterized in that: After the step of performing a first drying treatment on the silicon wafer that has been subjected to the etching liquid so that the etching liquid on the second sub-section is removed and the etching liquid remains on the first sub-section; and etching the first sub-section with the etching liquid on the first sub-section so that the thickness of the first sub-section is reduced, the method further includes: The silicon wafer is subjected to a first cleaning treatment to remove the etching liquid on the first sub-portion and the portion of the first sub-portion etched by the etching liquid.

6. The method for manufacturing a solar cell according to claim 5, characterized in that: The step of performing a first cleaning treatment on the silicon wafer to remove the etching solution on the first sub-portion and the portion of the first sub-portion etched by the etching solution comprises: The silicon wafer is placed in a first cleaning tank, and the first cleaning time is 55s to 75s.

7. The method for manufacturing a solar cell according to claim 5, characterized in that: The first drying process and the first cleaning process are separated by a first preset time period, and the first preset time period is 8s to 15s.

8. The method for manufacturing a solar cell according to claim 5, characterized in that: After the step of performing a first cleaning process on the silicon wafer to remove the etching liquid on the first sub-portion and the portion of the first sub-portion etched by the etching liquid, the method further includes: The silicon wafer is subjected to a second drying process.

9. The method for manufacturing a solar cell according to claim 8, characterized in that: In the second drying process, the second drying time is 350s to 450s, and the second drying temperature is 75°C to 95°C.

10. The method for manufacturing a solar cell according to claim 1, characterized in that: The first film layer is a doped semiconductor film layer or a passivation anti-reflection film layer; the doped semiconductor film layer is a doped polycrystalline silicon layer, a doped amorphous silicon layer, a doped microcrystalline silicon layer or a doped nanocrystalline silicon layer.

11. A solar cell, characterized in that: The solar cell is manufactured by the method for manufacturing a solar cell according to any one of claims 1 to 10.

12. A photovoltaic module, characterized in that: Comprising the solar cell according to claim 11.

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