Solar cell, manufacturing method thereof and photovoltaic module

Abstract

The invention provides a solar cell, a manufacturing method thereof and a photovoltaic module, and relates to the photovoltaic field. The solar cell comprises a substrate which comprises a first surface and a second surface which are opposite to each other, the first surface is provided with a groove, microstructures are arranged on the first surface of the periphery of the groove, the bottom surface of the groove and the side face of the groove respectively, and the multiple microstructures comprise a first conical structure, a second conical structure and a columnar structure, the height direction of the first conical structure intersects with the height direction of the second conical structure, and the side face of the columnar structure inclines towards the peripheral direction of the groove. The first passivation layer is located on the first surface. The problem that in the prior art, a solar cell is low in sunlight absorption rate is at least solved.

Description

Technical Field

[0001] The present application relates to the field of photovoltaics, and in particular, to a solar cell, a manufacturing method thereof, and a photovoltaic module. Background Art

[0002] At present, as a new energy alternative, solar cells are used more and more widely. Solar cells utilize the photovoltaic effect to generate carriers, and then use electrodes to extract the carriers, thereby facilitating the effective utilization of electrical energy.

[0003] In the prior art, the absorption rate of solar cells to sunlight is low, resulting in a low photoelectric conversion efficiency of solar cells.

[0004] The above information disclosed in the background art section is only used to enhance the understanding of the background art of the technology described herein. Therefore, the background art may contain certain information that is not prior art known to those skilled in the art in their own country. Summary of the Invention

[0005] The main object of the present application is to provide a solar cell, a manufacturing method thereof, and a photovoltaic module, so as to at least solve the problem that the absorption rate of solar cells to sunlight in the prior art is low.

[0006] To achieve the above object, according to one aspect of the present application, there is provided a solar cell, including: a substrate including opposite first and second surfaces, the first surface having a groove, and the first surface, the bottom surface, and the side surface of the groove respectively having microstructures on the outer periphery of the groove, the plurality of microstructures including: a first conical structure, a second conical structure, and a columnar structure, the height direction of the first conical structure intersecting the height direction of the second conical structure, and the side surface of the columnar structure being inclined toward the outer periphery direction of the groove; a first passivation layer located on the first surface.

[0007] Optionally, the columnar structure includes a first prism and a second prism, the planes where the side surfaces of the first prism and the second prism are located intersect, the side surface of the groove includes a first buffer area, a fuzzing area, and a second buffer area arranged in sequence along a first direction, the first prism is located in the first buffer area, the first conical structure is located in the fuzzing area, the second prism is located in the second buffer area, and the first direction is perpendicular to the first surface and points from the first surface to the second surface.

[0008] Optionally, the angle between the first surface and the side surface of the first prism is an acute angle.

[0009] Optionally, the angle between the bottom surface of the groove and the side surface of the second prism is an obtuse angle.

[0010] Optionally, the height of the first prism in the first direction is 0.5 - 2 μm.

[0011] Optionally, the height of the second prism in the first direction is 0.5 - 5 μm.

[0012] Optionally, the height of the first prism in the second direction is 0.5 - 2 μm, the second direction is perpendicular to the first direction and the first intersection line direction respectively, and the first intersection line direction is the extension direction of the intersection line of the side surface of the first prism and the first surface.

[0013] Optionally, the height of the second prism in the third direction is 0.5 - 2 μm, the third direction is perpendicular to the first direction and the second intersection line direction, and the second intersection line direction is the extension direction of the intersection line of the side surface of the first prism and the bottom surface of the groove.

[0014] Optionally, the depth of the groove in the fourth direction is 10 - 100 μm, the width of the groove in the fifth direction is 3 - 10 μm, the fourth direction is perpendicular to the first surface, and the fifth direction is perpendicular to the fourth direction.

[0015] Optionally, the height of the first conical structure is 0.5 - 3 μm.

[0016] Optionally, the second conical structure is located on the bottom surface of the groove and the first surface.

[0017] Optionally, the protrusion height of the second conical structure located on the bottom surface of the groove is the first height, and the protrusion height of the second conical structure located on the first surface is the second height, and the first height is less than the second height.

[0018] Optionally, the first passivation layer is further located on the bottom surface and the side surface of the groove. The solar cell further includes: a first doped conductive layer, which is located in the substrate and in contact with the first passivation layer, and the surface of the first doped conductive layer away from the second surface is part of the first surface; a tunneling oxide layer, which is located on the second surface; a second doped conductive layer, which is located on the side of the tunneling oxide layer away from the substrate, the second doped conductive layer has the same doping type as the substrate, and the second doped conductive layer has a different doping type from the first doped conductive layer; a second passivation layer, which is located on the side of the second doped conductive layer away from the tunneling oxide layer; a first electrode, which is located on the side of the first passivation layer away from the first doped conductive layer; and a second electrode, which is located on the side of the second passivation layer away from the second doped conductive layer.

[0019] Optionally, the first passivation layer is located on the first surface outside the periphery of the groove. The solar cell further includes: a third doped conductive layer located on the side of the first passivation layer on one side of the groove and away from the first surface; a fourth doped conductive layer located on the side of the first passivation layer on the other side of the groove and away from the first surface. The doping type of the fourth doped conductive layer is the same as that of the substrate, and the doping type of the third doped conductive layer is different from that of the fourth doped conductive layer; a third passivation layer located on the side of the third doped conductive layer and the fourth doped conductive layer away from the first passivation layer, on the bottom surface and the side surface of the groove; a fourth passivation layer located on the second surface; a third electrode located on the side of the third passivation layer away from the third doped conductive layer; and a fourth electrode located on the side of the third passivation layer away from the fourth doped conductive layer.

[0020] Optionally, the second surface has the groove. The solar cell further includes: a fifth doped conductive layer located on the side of the first passivation layer away from the first surface; a first transparent conductive layer located on the side of the fifth doped conductive layer away from the first passivation layer, on the bottom surface and the side surface of the groove on the first surface; a fifth passivation layer located on the second surface; a sixth doped conductive layer located on the side of the fifth passivation layer away from the second surface. The doping type of the sixth doped conductive layer is the same as that of the substrate, and the doping type of the sixth doped conductive layer is different from that of the fifth doped conductive layer; a second transparent conductive layer located on the side of the sixth doped conductive layer away from the fifth passivation layer, on the bottom surface and the side surface of the groove on the second surface; a fifth electrode located on the side of the first transparent conductive layer away from the fifth doped conductive layer; and a sixth electrode located on the side of the second transparent conductive layer away from the sixth doped conductive layer.

[0021] Optionally, the first passivation layer includes: a borosilicate glass layer located on the surface of the first doped conductive layer away from the second surface; a silicon oxide layer located on the bottom surface and the side surface of the groove; an aluminum oxide layer located on the side of the borosilicate glass layer away from the first doped conductive layer and on the side of the silicon oxide layer away from the bottom surface and the side surface of the groove; and an antireflection layer located on the side of the aluminum oxide layer away from the borosilicate glass layer and the silicon oxide layer.

[0022] Optionally, the thickness of the silicon oxide layer is 50 - 150 nm.

[0023] According to another aspect of the present application, a method for manufacturing a solar cell is provided, including: providing an initial structure, the initial structure including an initial substrate and an initial passivation layer, the initial substrate including opposite third and second surfaces, the third surface having microstructures thereon, and the initial passivation layer being located on the third surface; removing a part of the initial passivation layer and a part of the initial substrate to form an initial groove in the initial substrate; texturing the bottom surface and side surfaces of the initial groove to form the microstructures on the side surfaces and bottom surface of the initial groove respectively, the textured initial groove forming a groove, and the remaining initial substrate forming a substrate, the plurality of microstructures including: a first conical structure, a second conical structure, and a columnar structure, the height direction of the first conical structure intersecting the height direction of the second conical structure, and the side surface of the columnar structure being inclined towards the outer peripheral direction of the groove.

[0024] Optionally, texturing the bottom surface and side surfaces of the initial groove to form the microstructures on the side surfaces and bottom surface of the initial groove respectively includes: etching the bottom surface and side surfaces of the initial groove with a mixed solution at an ambient temperature of 60 - 90 °C to form the microstructures on the side surfaces and bottom surface of the initial groove respectively, the mixed solution including an alkaline solution and a texturing additive.

[0025] Optionally, the volume of the alkaline solution is 0.5 - 20 L, and the volume of the texturing additive is 0.5 - 10 L.

[0026] Optionally, the initial structure further includes an initial doped conductive layer in the initial substrate, the initial doped conductive layer being in contact with the initial passivation layer, and removing a part of the initial passivation layer and a part of the initial substrate to form an initial groove in the initial substrate includes: removing a part of the initial passivation layer by a laser etching process to expose a part of the initial doped conductive layer, and the remaining initial passivation layer forming an oxide layer; sequentially removing the exposed initial doped conductive layer and the exposed initial substrate by a wet etching process to obtain the initial groove.

[0027] Optionally, removing a part of the initial passivation layer by a laser etching process includes: etching and removing a part of the initial passivation layer with a laser beam having an output power of 10 - 90% of the maximum output power and a scanning speed of 5000 - 40000 mm / s, the laser beam including one of the following: an infrared laser beam, a ultraviolet laser beam, a green laser beam.

[0028] Optionally, the remaining initial doped conductive layer forms a first doped conductive layer, and the oxide layer is a borosilicate glass layer. After texturing the bottom surface and the side surfaces of the initial groove, the method further includes: forming a silicon oxide layer on the bottom surface and the side surfaces of the groove by an oxidation process; forming an aluminum oxide layer on the surface of the borosilicate glass layer away from the first doped conductive layer and on the surface of the silicon oxide layer away from the bottom surface and the side surfaces of the groove; forming an antireflection layer on the surface of the aluminum oxide layer away from the borosilicate glass layer and the silicon oxide layer to obtain a first passivation layer.

[0029] According to another aspect of the present application, a photovoltaic module is provided, including any one of the solar cells described above.

[0030] The present application has the following beneficial technical effects: In the solar cell, the first surface of the substrate has a groove, and microstructures are provided on the first surface of the substrate, on the bottom surface of the groove, and on the side surfaces of the groove. The plurality of microstructures include a first conical structure, a second conical structure, and a columnar structure, and the height directions of the first conical structure and the second conical structure are different. That is to say, the solar cell of the present application is provided with microstructures on the surfaces in two intersecting directions, namely the surface and the side surface. Under the combined action of the two groups of microstructures in different directions, light at more angles can be scattered and enter the interior of the solar cell, thereby effectively suppressing the specular reflection effect of light, greatly reducing the light reflection loss, improving the light trapping effect, and thus improving the overall light absorption efficiency of the solar cell. Moreover, since a variety of microstructures can provide a variety of reflection surfaces, the incident light energy can interact with surfaces of various angles and curvatures, so that the incident light can be reflected multiple times in different directions, increasing the propagation path length of the light inside the solar cell. The farther the light propagates inside the cell, the more opportunities it has to interact with the cell material, thereby greatly increasing the generation probability of photo-generated carriers and improving the photoelectric conversion efficiency of the cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The specification drawings forming a part of the present application are used to provide a further understanding of the present application. The schematic embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation to the present application. In the drawings:

[0032] Figure 1 A schematic partial cross-sectional structure diagram of a solar cell provided in an embodiment of the present application is shown;

[0033] Figure 2 A schematic partial cross-sectional structure diagram of another solar cell provided in an embodiment of the present application is shown;

[0034] Figure 3Shows an SEM (Scanning Electron Microscope) test diagram of a solar cell provided according to an embodiment of the present application;

[0035] Figure 4 Shows a schematic diagram of a partial cross-sectional structure of a TOPCon solar cell provided according to an embodiment of the present application;

[0036] Figure 5 Shows a schematic diagram of a partial cross-sectional structure of a back-contact solar cell provided according to an embodiment of the present application;

[0037] Figure 6 Shows a schematic diagram of a partial cross-sectional structure of a heterojunction solar cell provided according to an embodiment of the present application;

[0038] Figure 7 Shows a schematic flowchart of a manufacturing method of a solar cell provided according to an embodiment of the present application;

[0039] Figure 8 Shows a schematic diagram of a partial cross-sectional structure of an initial structure provided according to an embodiment of the present application;

[0040] Figure 9 Shows a schematic diagram of a structure obtained after removing a part of the initial passivation layer provided according to an embodiment of the present application;

[0041] Figure 10 Shows a schematic diagram of a structure after forming an initial groove provided according to an embodiment of the present application;

[0042] Figure 11 Shows a schematic diagram of a partial cross-sectional structure of another solar cell provided according to an embodiment of the present application;

[0043] Figure 12 Shows a schematic diagram of a single-crystal silicon crystal structure provided according to an embodiment of the present application;

[0044] Figure 13 Shows schematic diagrams of three crystal orientations of a single-crystal silicon crystal provided according to an embodiment of the present application;

[0045] Figure 14 Shows a schematic diagram of a rhombus structure composed of 111 crystal orientations of multiple adjacent unit cells of a single-crystal silicon provided according to an embodiment of the present application;

[0046] Figure 15 Shows an SEM test diagram of a second conical structure in a solar cell provided according to an embodiment of the present application.

[0047] Among them, the above-mentioned drawings include the following reference numerals:

[0048] 10. Substrate; 11. Groove; 12. First conical structure; 13. Second conical structure; 14. Columnar structure; 15. First doped conductive layer; 16. First prism; 17. Second prism; 18. First passivation layer; 19. Tunneling oxide layer; 20. Second doped conductive layer; 21. Second passivation layer; 22. First electrode; 23. Second electrode; 25. First transparent conductive layer; 26. Second transparent conductive layer; 27. First antireflection layer; 28. Second antireflection layer; 29. Initial substrate; 30. Initial doped conductive layer; 31. Initial groove; 32. Initial passivation layer; 33. Oxide layer; 34. Third doped conductive layer; 35. Fourth doped conductive layer; 36. Third passivation layer; 37. Fourth passivation layer; 38. Third electrode; 39. Fourth electrode; 40. Fifth doped conductive layer; 41. Sixth doped conductive layer; 42. Fifth passivation layer; 43. Fifth electrode; 44. Sixth electrode; 45. Third antireflection layer; 46. Fourth antireflection layer. Detailed implementation manners

[0049] It should be noted that, without conflict, the embodiments in the present application and the features in the embodiments may be combined with each other. The present application will be described in detail below with reference to the drawings and in combination with the embodiments.

[0050] The present application will be further described in detail below with reference to specific embodiments, and these embodiments should not be construed as limiting the scope claimed by the present application.

[0051] In order to enable those skilled in the art to better understand the solution of the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present application.

[0052] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the drawings are used to distinguish similar objects, and do not necessarily need to describe a specific order or sequence. It should be understood that such data can be interchanged under appropriate circumstances so as to describe the embodiments of the present application here. In addition, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device comprising a series of steps or units does not necessarily have to be limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0053] As introduced in the background art, there is a problem in the prior art that the absorption rate of sunlight by solar cells is relatively low. To solve this technical problem, embodiments of the present application provide a solar cell, a manufacturing method thereof, and a photovoltaic module.

[0054] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present application.

[0055] Embodiments of the present application provide a solar cell. Figure 1 Exemplarily, a schematic cross-sectional structure diagram of a solar cell according to an embodiment of the present application is shown, as Figure 1 shown, the solar cell includes:

[0056] A substrate 10, including opposite first and second surfaces, the first surface having a groove 11, and the first surface outside the periphery of the groove 11, the bottom surface of the groove 11, and the side surface of the groove 11 respectively having microstructures. The plurality of microstructures include: a first conical structure 12, a second conical structure 13, and a columnar structure 14. The height direction of the first conical structure 12 intersects with the height direction of the second conical structure 13. The side surface of the columnar structure 14 is inclined towards the outer periphery direction of the groove;

[0057] Specifically, the outer periphery direction of the groove 11 is the direction from the groove 11 to the first surface outside the periphery of the groove 11. The side surface of the columnar structure 14 being inclined towards the outer periphery direction of the groove means that the side surface of the columnar structure 14 is not perpendicular to the first surface, but has a certain inclination angle relative to the first surface. At least part of the first conical structure 12, the second conical structure 13, and the columnar structure 14 is located on the first surface, at least part of the first conical structure 12, the second conical structure 13, and the columnar structure 14 is located on the bottom surface of the groove, and at least part of the first conical structure 12, the second conical structure 13, and the columnar structure 14 is located on the side surface of the groove. The first conical structure 12 and the second conical structure 13 may specifically be pyramid structures, such as pyramid structures. The columnar structure 14 may specifically be a prism structure. The height direction of the first conical structure 12 may be perpendicular to the height direction of the second conical structure 13. The substrate may be a silicon substrate, and the material of the silicon substrate may include single crystal silicon, polycrystalline silicon, amorphous silicon, and microcrystalline silicon, etc.

[0058] A first passivation layer 18, located on the first surface.

[0059] In the described embodiment, there are grooves on the first surface of the substrate, and microstructures are provided on the first surface of the substrate, on the bottom surface of the groove, and on the side surface of the groove. The multiple microstructures include a first conical structure, a second conical structure, and a columnar structure, and the height directions of the first conical structure and the second conical structure are different. That is to say, the solar cell of the present application is provided with microstructures on the surfaces in two intersecting directions, namely the surface and the side surface. Under the combined action of the two groups of microstructures in different directions, light at more angles can be scattered and enter the interior of the solar cell, thereby effectively suppressing the specular reflection effect of light, greatly reducing the light reflection loss, improving the light trapping effect, and thus improving the overall light absorption efficiency of the solar cell. Moreover, since multiple microstructures can provide multiple reflection surfaces, the incident light energy can interact with surfaces of multiple angles and curvatures, so that the incident light can be reflected multiple times in different directions, increasing the propagation path length of the light inside the solar cell. The farther the light propagates inside the cell, the more opportunities it has to interact with the cell material, thereby greatly increasing the generation probability of photo-generated carriers and improving the photoelectric conversion efficiency of the cell.

[0060] In the microstructures of the present application, there are multiple first conical structures, multiple second conical structures, and multiple columnar structures, and the multiple first conical structures, the multiple second conical structures, and the multiple columnar structures are densely distributed on the substrate.

[0061] In the present application, the described columnar structure is a micro-convex structure located on at least one of the first surface, the bottom surface of the groove, and the side surface. The columnar structure may include a structure surrounded by two opposite surfaces (referred to as the upper surface and the lower surface) and at least one side surface. In the columnar structure, the upper surface and the lower surface may be parallel or non-parallel; in the case where there are multiple side surfaces, the common edges of every two adjacent quadrilateral side surfaces may be parallel or non-parallel. That is to say, the columnar structure may include at least one of a prism, a cylinder, a pseudo-prism (i.e., the case where the upper and lower surfaces of the prism are non-parallel and / or the common edges of the side surfaces are non-parallel), and a pseudo-cylinder (i.e., the case where the upper and lower surfaces of the cylinder are non-parallel).

[0062] The described prism, cylinder, pseudo-prism, and pseudo-cylinder may be regular prisms or oblique prisms. In the case where the columnar structure includes a prism and / or a pseudo-prism, it may specifically be a triangular prism, a pseudo-triangular prism, a quadrangular prism, a pseudo-quadrangular prism, a pentagonal prism, or a pseudo-pentagonal prism, etc.

[0063] In the present application, the first conical structure and the second conical structure may specifically be a tetrahedral pyramid, also called a pyramid structure.

[0064] Since there are three types of microstructures, namely the first conical structure, the second conical structure, and the columnar structure, in some exemplary solutions, the first type of microstructure can be provided on the first surface of the outer periphery of the groove, the second type of microstructure can be provided on the side surface of the groove, and the third type of microstructure can be provided on the bottom surface of the groove. That is, the types of microstructures provided on any two of the first surface, the side surface of the groove, and the bottom surface are different. For example, a plurality of second conical structures are provided on the first surface, a plurality of first conical structures are provided on the side surface of the groove, and a plurality of prism structures are provided on the bottom surface of the groove. In some other exemplary solutions, two types of microstructures can be provided on the first surface of the outer periphery of the groove, two types of microstructures can be provided on the side surface of the groove, and two types of microstructures can be provided on the bottom surface of the groove. Some of the microstructures provided on any two of the first surface, the side surface of the groove, and the bottom surface are the same. For example, the second conical structure and the prism structure are provided on the first surface, the first conical structure and the prism structure are provided on the side surface of the groove, and the second conical structure and the prism structure are provided on the bottom surface of the groove. In some other exemplary solutions, three types of microstructures are provided on the first surface of the outer periphery of the groove, on the side surface of the groove, and on the bottom surface of the groove. In some other exemplary solutions, one type of microstructure is provided on at least one of the first surface of the outer periphery of the groove, the side surface of the groove, and the bottom surface of the groove, and multiple types of microstructures are provided on the remaining surfaces. The types of microstructures on the three surfaces can be the same or different. For example, the second conical structure is provided on the first surface, the second conical structure is provided on the bottom surface of the groove, and the first conical structure and the prism structure are provided on the side surface of the groove; or, the second conical structure and the prism structure are provided on the first surface, the second conical structure is provided on the bottom surface of the groove, and the first conical structure and the prism structure are provided on the side surface of the groove. Of course, the setting methods of the microstructures on the first surface of the outer periphery of the groove, the side surface of the groove, and the bottom surface of the groove are not limited to the above exemplary solutions. In addition to the above exemplary solutions, those skilled in the art can also flexibly set the types of microstructures on the first surface of the outer periphery of the groove, the side surface of the groove, and the bottom surface of the groove according to actual needs.

[0065] In some alternative embodiments, as Figure 1 , Figure 2 and Figure 3 shown, the columnar structure 14 includes a first prism 16 and a second prism 17. The planes where the side surfaces of the first prism 16 are located intersect with the planes where the side surfaces of the second prism 17 are located. The side surface of the groove 11 includes a first buffer zone, a fluff discharging zone, and a second buffer zone arranged in sequence along a first direction. The first prism 16 is located in the first buffer zone, the first conical structure 12 is located in the fluff discharging zone, and the second prism 17 is located in the second buffer zone. The first direction is perpendicular to the first surface and points from the first surface to the second surface. That is to say, the first direction is the direction from the opening of the groove 11 to the bottom surface of the groove 11.

[0066] In the described embodiment, on the side surface of the groove, the first buffer and the second buffer are located on both sides of the fuzzing area. The two buffers can ensure the normal growth and morphological optimization of the conical-shaped fuzz surface in the fuzzing area, and further realize the formation of a first conical structure in the fuzzing area where the height direction intersects (for example, is perpendicular to) the first direction. The first conical structure is used to capture the light that is not effectively absorbed by the microstructures on the first surface of the substrate, thereby further improving the light trapping ability of the solar cell. In addition, the first prism formed by the first buffer and the prism structure formed by the second buffer can further increase the roughness of the side surface of the groove, further reduce the direct reflection of light by the side surface, and further reduce the escape of light when the light is reflected back from the inside of the cell to the surface, thereby further improving the light capture efficiency. This design of the multi-level microstructures on the side surface of the groove further solves the problem of low light capture efficiency in traditional solar cells. By adjusting the arrangement of the microstructures, the path of light inside the cell can be precisely controlled, significantly improving the light absorption efficiency and conversion efficiency of the cell.

[0067] In some exemplary embodiments, the first prism may specifically include one or more of a triangular prism, a quasi-triangular prism, a quadrangular prism, and a quasi-quadrangular prism. The second prism may specifically include at least one of a triangular prism and a quasi-triangular prism.

[0068] In some embodiments, the fuzzing area is the growth area of the first conical structure 12. In this area, the etching solution can penetrate and act on the surface of the substrate 10 to form an efficient fuzz surface structure, such as the first conical structure 12 in the shape of a pyramid. This area can improve the light trapping ability and short-circuit current of the cell, allowing the fuzz surface structure to develop to the maximum extent, capturing more sunlight and converting it into electrical energy.

[0069] In some embodiments, as Figure 2 shown, a plurality of the first prisms 16 are located in the first buffer, and the side surfaces of the plurality of the first prisms 16 serve as part of the side surface of the groove 11. A plurality of the second prisms 17 are located in the second buffer, and the side surfaces of the plurality of the second prisms 17 serve as part of the side surface of the groove 11.

[0070] In one implementation manner of the present application, as Figure 2 shown, the included angle θ between the first surface and the side surface of the first prism 16 is an acute angle. As Figure 2As shown, the first prism 16 is adjacent to the first surface. The side surface of the first prism 16 is inclined towards the outer peripheral direction of the groove 11, such that an acute angle in the shape of a brim is formed between the first surface and the side surface of the first prism 16. This shape structure can not only prevent the etching process of the microstructure on the side surface of the groove 11 from damaging the first surface of the substrate 10, but also ensure a good morphology of the first conical structure 12 on the side close to the first buffer zone in the flocking area, and a complete flocked surface structure can be formed, playing a role in the formation transition of the morphology of the first conical structure 12.

[0071] It should be noted that among the acute angles between the first surface and the side surface of the first prism 16, "the first surface" refers to the plane where the base of the microstructure on the first surface is located, and this plane is parallel to the second surface. In other words, the angle θ between the second surface and the extended surface of the side surface of the first prism 16 is an acute angle.

[0072] Moreover, the acute angle design between the first surface and the side surface of the first prism 16 enables the incident light to be reflected at a larger incident angle when contacting the first prism 16, increasing the path length of the light inside the battery. This design utilizes the principle of total internal reflection of light. Even when the light is incident perpendicularly, the light can be guided to a longer path through the inclined surface of the prism, thereby improving the light absorption efficiency.

[0073] In some embodiments, as Figure 2 shown, the angle α between the bottom surface of the groove 11 and the side surface of the second prism 17 is an obtuse angle. As Figure 2 shown, the second prism 17 is adjacent to the bottom surface of the groove 11. The side surface of the second prism 17 is inclined towards the outer peripheral direction of the groove 11, such that an obtuse angle is formed between the bottom surface of the groove 11 and the side surface of the second prism 17. This shape structure can not only prevent the etching process of the microstructure on the side surface of the groove 11 from damaging the bottom surface of the groove 11, but also ensure a good morphology of the first conical structure 12 on the side close to the second buffer zone in the flocking area, and a complete flocked surface structure can be formed, playing a role in the formation transition of the morphology of the first conical structure 12.

[0074] It should be noted that among the obtuse angles between the bottom surface of the groove 11 and the side surface of the second prism 17, "the bottom surface of the groove 11" refers to the plane where the base of the bottom microstructure is located, and this plane is parallel to the second surface. In other words, the angle α between the second surface and the extended surface of the side surface of the second prism 17 is an acute angle.

[0075] And Figure 2In [the figure], the obtuse angle design between the bottom surface of the groove 11 and the side surface of the second prism 17 enables the light reflected from the inside of the battery to be reflected again at a larger angle when contacting the second prism 17, increasing the number of reflections and the path length of the light. This design utilizes the principle of multiple reflections of light. Even when the light is reflected from the inside of the battery at a small angle, the light can be scattered again through the inclined surface of the second prism 17, thereby improving the light absorption efficiency.

[0076] In some other embodiments of the present application, such as Figure 2 As shown, the height h1 of the first prism 16 in the first direction is 0.5 - 2 μm. For example, the height h1 of the first prism 16 in the first direction can be 0.5 μm, 0.8 μm, 1.0 μm, 1.3 μm, 1.6 μm, or 2 μm, etc. Of course, it can also be other values within the range. By setting the height of the first prism 16 along the first direction within the height range, it can be further ensured that the complete conical structure can be exposed in the flocking area after etching, thereby further ensuring that the morphology of the first conical structure 12 is better.

[0077] According to some other embodiments of the present application, such as Figure 2 As shown, the height h2 of the second prism 17 in the first direction is 0.5 - 5 μm. For example, the height of the second prism 17 in the first direction can be 0.5 μm, 1.0 μm, 1.5 μm, 2 μm, 3 μm, 4 μm, 4.5 μm, or 5 μm, etc. Of course, it can also be other values within the range. By setting the height of the second prism 17 along the first direction within the height range, it can be further ensured that the complete conical structure can be exposed in the flocking area after etching, thereby further ensuring that the morphology of the first conical structure 12 is better.

[0078] In some embodiments, such as Figure 2 As shown, the height h3 of the first prism 16 in the second direction is 0.5 - 2 μm. The second direction is perpendicular to the first direction and the first intersection direction respectively. The first intersection direction is the extension direction of the intersection line of the side surface of the first prism 16 and the first surface. For example, the height h3 of the first prism 16 in the second direction can be 0.5 μm, 0.6 μm, 0.8 μm, 1 μm, 1.6 μm, 1.9 μm, or 2 μm, etc. Of course, it can also be other values within the range. By setting the height of the first prism 16 along the second direction within the height range, the first conical structure 12 with the required height can be obtained, thereby further ensuring that the morphology of the first conical structure 12 is better.

[0079] In some embodiments, such as Figure 2As shown, the height h4 of the second prism 17 in the third direction is 0.5 - 2 μm. The third direction is perpendicular to the first direction and the second intersection line direction. The second intersection line direction is the extension direction of the intersection line between the side surface of the first prism 16 and the bottom surface of the groove 11. For example, the height h4 of the second prism 17 in the third direction can be 0.5 μm, 0.6 μm, 0.8 μm, 1 μm, 1.6 μm, 1.9 μm, or 2 μm, etc. Of course, it can also be other values within this range. By setting the height of the second prism 17 in the third direction to this height range, a first conical structure 12 with the required height can be obtained, thereby further ensuring a better morphology of the first conical structure 12.

[0080] It should be noted that the second direction is the same as or opposite to the third direction. The height of the first prism 16 in the second direction and the height of the second prism 17 in the third direction are the etching depths for etching the side surface of the groove 11.

[0081] In an alternative solution, as Figure 2 shown, the depth h5 of the groove 11 in the fourth direction is 10 - 100 μm. For example, the depth h5 of the groove 11 in the fourth direction can be 10 μm, 30 μm, 50 μm, 70 μm, or 100 μm, etc. Of course, it can also be other values within this range; the width w of the groove 11 in the fifth direction is 3 - 10 μm. For example, the width of the groove 11 in the fifth direction can be 3 μm, 5 μm, 6 μm, 8 μm, 9 μm, or 10 μm, etc. Of course, it can also be other values within this range; the fourth direction is perpendicular to the first surface, and the fifth direction is perpendicular to the fourth direction. This depth and width range is determined based on the wavelength of light and the absorption characteristics of the battery material. This range further ensures that after light enters the groove 11, it can undergo multiple reflections and scattering, increasing the path length of light inside the battery, improving the light absorption efficiency, and further increasing the scattering and absorption of light inside the battery.

[0082] In some embodiments, the fourth direction can be the same as or opposite to the first direction. The fifth direction can be the same as or opposite to the second direction and the third direction respectively.

[0083] Since the pyramid morphology of the fluff-emitting region (i.e., the first conical structure 12) requires a certain height, that is, a certain depth needs to be etched into the substrate to expose the diamond-shaped spire structure, the setting of the first buffer zone and the second buffer zone enables the fluff-emitting region to form the first conical structure 12 with a spire structure. Additionally, if the depth h5 of the groove in the fourth direction is less than or equal to the sum of h1 and h2, a complete fluff surface structure will not be formed in the fluff-emitting region, and only depressions will be formed. Therefore, h5 > (h1 + h2) is set.

[0084] Furthermore, the height of the first conical structure 12 is 0.5 - 3 μm. For example, the height of the first conical structure 12 can be 0.5 μm, 1 μm, 1.5 μm, 2 μm, 2.5 μm, or 3 μm, etc. Of course, it can also be other values within the range. Setting the height of the first conical structure 12 within this range can further ensure the effective scattering of incident light and avoid the problem of low light utilization rate caused by the light trapping effect, thereby further achieving the effect of improving the light absorption rate and the short-circuit current of the battery.

[0085] Among them, the height direction of the first conical structure 12 can be perpendicular to the first direction or intersect the first direction at an acute angle.

[0086] In some embodiments, the second conical structure 13 is located on the bottom surface of the groove 11 and the first surface. The second conical structure 13 located on the bottom surface and the first surface of the groove 11 increases the probability that incident light incident on the bottom surface and the first surface of the groove 11 at different angles is absorbed after at least one reflection by the second conical structure 13, and the probability that the light is reflected to the side surface of the groove 11 after at least one reflection by the second conical structure 13 and then absorbed after at least one reflection by the first conical structure 12, thereby facilitating the improvement of the light absorption rate of the first surface of the substrate 10, the bottom surface of the groove 11, and the side surface for incident light.

[0087] Furthermore, the height of the second conical structure 13 is 0.5 - 3 μm. For example, the height of the second conical structure 13 can be 0.5 μm, 1 μm, 1.5 μm, 2 μm, 2.5 μm, or 3 μm, etc. Of course, it can also be other values within the range.

[0088] In some embodiments, the height direction of the second conical structure 13 can be parallel to the first direction, that is, the height of the second conical structure 13 is perpendicular to the height of the first conical structure 12; the height of the second conical structure 13 can also intersect the first direction at an acute angle.

[0089] In some other embodiments, the protruding height of the second conical structure 13 on the bottom surface of the groove 11 is a first height, and the protruding height of the second conical structure 13 on the first surface is a second height, and the first height is less than the second height. The second conical structure 13 on the first surface has a higher protruding height, which can more effectively scatter vertically and obliquely incident light, increase the path length of light inside the battery, and thus improve the light absorption rate; while the second conical structure 13 on the bottom surface of the groove 11 has a smaller protruding height, which can reduce the additional carrier transport time introduced by light scattering while maintaining the light scattering effect, and help the carriers move quickly to the electrodes. In addition, the second conical structure 13 with a higher protruding height can be formed on the first surface by a standard process, and forming the second conical structure 13 with a lower height on the bottom surface of the groove 11 is beneficial to reducing the process control complexity.

[0090] Of course, in addition to the above height relationship, when those skilled in the art design the structure of the solar cell, the first height can also be set to be the same as the second height; the first height can also be set to be greater than the second height.

[0091] In this application, the reflectivity of the first conical structure 12 and the second conical structure 13 can be 5% - 20% respectively. The base side length of the first conical structure 12 and the second conical structure 13 can be 2μm - 5μm.

[0092] In actual application, the solar cell of this application can be various types of solar cells. For example, the solar cell of this application can be a TOPCon (Tunnel Oxide Passivated Contact) cell, a BC (Back Contact) cell, an HJT (Heterojunction with Intrinsic Thin Layer) cell, or a Perc (Passivated Emitter and Rear Cell) cell.

[0093] The embodiment of this application provides a cell structure of a TOPCon solar cell, as Figure 4 shown, the first passivation layer 18 is also located on the bottom surface and the side surface of the groove 11, and the solar cell further includes:

[0094] A first doped conductive layer 15, which is located in the substrate 10 and in contact with the first passivation layer 18, and the surface of the first doped conductive layer 15 away from the second surface is part of the first surface;

[0095] The tunneling oxide layer 19 is located on the second surface;

[0096] The second doped conductive layer 20 is located on the side of the tunneling oxide layer 19 away from the substrate 10. The second doped conductive layer 20 has the same doping type as the substrate 10, and the second doped conductive layer 20 has a different doping type from the first doped conductive layer 15;

[0097] Specifically, when the doping types of the substrate 10 and the second doped conductive layer 20 are P-type doping, the doping type of the first doped conductive layer 15 is N-type; when the doping types of the substrate 10 and the second doped conductive layer 20 are N-type doping, the doping type of the first doped conductive layer 15 is P-type.

[0098] The second passivation layer 21 is located on the side of the second doped conductive layer 20 away from the tunneling oxide layer 19;

[0099] The first electrode 22 is located on the side of the first passivation layer 18 away from the first doped conductive layer 15;

[0100] Specifically, the orthographic projection of the first electrode 22 on the substrate 10 is located in the first doped conductive layer 15. The first electrode 22 makes electrical contact with the first doped conductive layer 15.

[0101] The second electrode 23 is located on the side of the second passivation layer 21 away from the second doped conductive layer 20.

[0102] Specifically, the second electrode 23 makes electrical contact with the second doped conductive layer 20.

[0103] In this embodiment, the first passivation layer 18 and the second passivation layer 21 can play a passivation effect, reduce the carrier recombination loss between the doped conductive layer and the electrode, improve the short-circuit current and open-circuit voltage of the TOPCon solar cell, thereby improving the cell conversion efficiency; the tunneling oxide layer 19 can achieve selective transport of carriers; the second doped conductive layer 20 plays a field passivation role; the first doped conductive layer 15 and the substrate 10 form a PN junction.

[0104] Among them, Figure 4 An embodiment in which the second surface is not textured is exemplarily shown. In other embodiments, the second surface may also have the second conical structure.

[0105] Optionally, the first surface of the substrate 10 includes alternating first regions and third regions. The first doped conductive layer 15 contacts the first regions, and the grooves 11 are located in the third regions. In this embodiment, the first doped conductive layer 15 contacts the first regions and does not contact the third regions, which can reduce the carrier recombination loss in the third regions, improve the short-circuit current of the battery, and reduce the saturation dark current density in the third regions.

[0106] Optionally, the material of the first passivation layer 18 may be one or more of silicon oxide, aluminum oxide, silicon nitride, silicon oxynitride, or carbon oxynitride. In some embodiments, the first passivation layer 18 may be a single-layer structure. In other embodiments, the first passivation layer 18 may also be a multi-layer structure. In some embodiments, the first passivation layer 18 may be formed by a PECVD (Plasma Enhanced Chemical Vapor Deposition) method.

[0107] Optionally, the material of the second passivation layer 21 may be one or more of silicon oxide, aluminum oxide, silicon nitride, silicon oxynitride, or carbon oxynitride. In some embodiments, the second passivation layer 21 may be a single-layer structure. In other embodiments, the second passivation layer 21 may also be a multi-layer structure. In some embodiments, the second passivation layer 21 may be formed by a PECVD method.

[0108] Optionally, the materials and film layer structures of the first passivation layer 18 and the second passivation layer 21 may be the same or different.

[0109] Optionally, the first passivation layer 18 can prevent metal atoms in the first electrode 22 from diffusing into the first doped conductive layer 15, reduce the carrier recombination loss between the first electrode 22 and the first conductive layer, and reduce problems such as low photoelectric conversion efficiency of the solar cell caused by carrier recombination loss.

[0110] Optionally, the tunneling oxide layer 19 can cause an asymmetric shift in the energy band of the second surface, such that the potential barrier of the majority carriers in the carriers is lower than the potential barrier of the minority carriers. Therefore, the majority carriers can more easily perform quantum tunneling through the tunneling oxide layer 19, while the minority carriers can hardly pass through the tunneling oxide layer 19, thereby achieving selective transport of carriers. In addition, the tunneling oxide layer 19 can also achieve the effect of chemical passivation of the substrate 10. In some embodiments, the material of the tunneling oxide layer 19 may be a dielectric material, such as silicon oxide.

[0111] Optionally, the material of the second doped conductive layer 20 may be doped silicon, and the doped silicon may specifically include doped polysilicon, doped microcrystalline silicon, or doped amorphous silicon, etc.

[0112] Optionally, the solar cell is a single-sided cell, i.e., it receives solar light only through the first surface of the substrate 10. In some embodiments, the solar cell is a double-sided cell, i.e., both the first surface and the second surface of the substrate 10 are used to receive solar light.

[0113] Optionally, the substrate 10 is an N-type semiconductor substrate 10, i.e., the substrate 10 is doped with N-type ions, and the N-type ions can be any one of phosphorus, arsenic, or antimony. The first doped conductive layer 15 can be a P-type doped layer doped with P-type ions, and the P-type ions can be any one of boron, aluminum, or gallium. The first doped conductive layer 15 and the substrate 10 form a PN junction. The first doped conductive layer 15 can be obtained by diffusing and doping P-type ions on the surface layer of the substrate 10, and the doped part of the substrate 10 is converted into the first doped conductive layer 15. The second doped conductive layer 20 is an N-type conductive layer doped with N-type ions.

[0114] Optionally, as Figure 4 shown, both the first passivation layer 18 and the second passivation layer 21 are single-layer film structures. The solar cell may further include: a first antireflection layer 27, located between the first passivation layer 18 and the first electrode 22 and covering the surface of the first passivation layer 18 away from the first doped conductive layer 15 and the groove 11; a second antireflection layer 28, located between the second passivation layer 21 and the second electrode 23 and covering the surface of the second passivation layer 21 away from the second doped conductive layer 20.

[0115] Optionally, the first passivation layer is a multi-layer film structure, and specifically includes: a borosilicate glass layer located on the surface of the first doped conductive layer away from the second surface; a silicon oxide layer located on the bottom surface and the side surfaces of the groove; an aluminum oxide layer located on the side of the borosilicate glass layer away from the first doped conductive layer and on the side of the silicon oxide layer away from the bottom surface and the side surfaces of the groove; an antireflection layer located on the side of the aluminum oxide layer away from the borosilicate glass layer and the silicon oxide layer. In this embodiment, the borosilicate glass layer can effectively passivate the surface defects of the first doped conductive layer, reduce the surface recombination rate, and thus improve the open-circuit voltage of the battery; forming a silicon oxide layer on the bottom surface and the side surfaces of the groove not only has a passivation effect, but also, due to its refractive index being higher than that of air, can reduce the direct reflection of light on the surface, promote the heat dissipation and absorption of light inside the battery, increase the short-circuit current of the battery, and play a role in light management; forming an aluminum oxide layer on the borosilicate glass layer and the silicon oxide layer can further reduce the surface recombination; forming an antireflection layer on the outermost layer of the light-receiving surface of the battery, this film layer directly faces the incident light and has the characteristic of a low refractive index, which can greatly reduce the reflection loss of light, ensure that more light can penetrate into the battery interior, and improve the short-circuit current.

[0116] Optionally, the thickness of the silicon oxide layer is 50 - 150 nm. For example, the thickness of the silicon oxide layer can be 60 nm, 80 nm, or 100 nm, etc. Of course, it can also be other values within this range. Within this thickness range, the silicon oxide layer can effectively passivate the surface defects, increase the open-circuit voltage (Voc) by reducing the non-radiative recombination, thereby improving the photoelectric conversion efficiency of the battery; at the same time, this thickness range helps to maintain the stability of the structure and the mechanical strength of the battery.

[0117] Optionally, the thickness of the first doped conductive layer 15 can be 0.1 - 1 μm. The thickness of the tunneling oxide layer 19 can be 1 - 3 nm. The thickness of the second doped conductive layer 20 can be 50 - 300 nm. The doping concentration of the second doped conductive layer 20 can be 1×10 17 cm -3 ~1×10 20 cm -3 . The thickness of the aluminum oxide layer can be 2 - 10 nm.

[0118] An embodiment of the present application provides a battery structure of a back-contact solar cell. As Figure 5 shown, the first passivation layer 18 is located on the first surface outside the periphery of the groove 11, and the solar cell further includes:

[0119] A third doped conductive layer 34 located on the side of the first passivation layer 18 away from the first surface on one side of the groove 11;

[0120] Specifically, the third doped conductive layer 34 is located on one side of the groove 11 and on the side of the first passivation layer 18 away from the first surface.

[0121] A fourth doped conductive layer 35, located on the side of the first passivation layer 18 away from the first surface on the other side of the groove 11, the fourth doped conductive layer 35 having the same doping type as the substrate 10, and the third doped conductive layer 34 having a different doping type from the fourth doped conductive layer 35;

[0122] Specifically, the fourth doped conductive layer 35 is located on the other side of the groove 11 and on the side of the first passivation layer 18 away from the first surface. The third doped conductive layer 34 and the fourth doped conductive layer 35 are isolated by the groove 11.

[0123] A third passivation layer 36, located on the side of the third doped conductive layer 34 and the fourth doped conductive layer 35 away from the first passivation layer 18, on the bottom surface of the groove 11, and on the side surface of the groove 11;

[0124] A fourth passivation layer 37, located on the second surface;

[0125] A third electrode 38, located on the side of the third passivation layer 36 away from the third doped conductive layer 34;

[0126] Specifically, the orthographic projection of the third electrode 38 on the substrate 10 is located within the orthographic projection of the third doped conductive layer 34 on the substrate 10. The third electrode 38 forms an electrical contact with the third doped conductive layer 34.

[0127] A fourth electrode 39, located on the side of the third passivation layer 36 away from the fourth doped conductive layer 35.

[0128] Specifically, the orthographic projection of the fourth electrode 39 on the substrate 10 is located within the orthographic projection of the fourth doped conductive layer 35 on the substrate 10. The fourth electrode 39 forms an electrical contact with the fourth doped conductive layer 35.

[0129] In the described embodiment, the first passivation layer 18 can reduce the recombination rate of photo-generated electrons and photo-generated holes in the substrate 10 at the first surface of the substrate 10; the third doped conductive layer 34 and the fourth doped conductive layer 35 are separated by the groove 11, reducing the possibility of leakage current occurring between the third doped conductive layer 34 and the fourth doped conductive layer 35, and improving the reliability of the solar cell; the third passivation layer 36 and the fourth passivation layer 37 can enhance the surface carrier concentration of the back-contact solar cell, improve the short-circuit current and open-circuit voltage of the back-contact solar cell, thereby improving the cell efficiency; the third doped conductive layer 34 and the substrate 10 form a PN junction.

[0130] Among them, as Figure 5 shown, the second surface of the substrate 10 has a microstructure, specifically, it has the second conical structure 13.

[0131] Optionally, the first surface can be the back surface of the solar cell, that is, the surface not directly irradiated by sunlight. The second surface can be the front surface of the solar cell, that is, the surface that can be directly irradiated by sunlight.

[0132] Optionally, the material of the third passivation layer 36 can be one or more of silicon oxide, aluminum oxide, silicon nitride, silicon oxynitride, or carbon oxynitride. In some embodiments, the third passivation layer 36 can be a single-layer structure. In other embodiments, the third passivation layer 36 can also be a multi-layer structure.

[0133] Optionally, the material of the fourth passivation layer 37 can be one or more of silicon oxide, aluminum oxide, silicon nitride, silicon oxynitride, or carbon oxynitride. In some embodiments, the fourth passivation layer 37 can be a single-layer structure. In other embodiments, the fourth passivation layer 37 can also be a multi-layer structure.

[0134] Optionally, the first passivation layer 18 can include at least one of silicon oxide, aluminum oxide, silicon nitride, silicon oxynitride, amorphous silicon, and polycrystalline silicon. The lattice of the first passivation layer 18 can be well matched with the lattice of the substrate 10, that is, the first passivation layer 18 can well passivate the first surface of the substrate 10 to reduce the recombination rate of photo-generated electrons and photo-generated holes in the substrate 10 at the first surface. The first passivation layer 18 and the P-type doping layer can form a tunneling passivation contact structure, and this tunneling passivation contact structure can improve the efficiency of the P-type doping layer in collecting holes. The first passivation layer 18 and the N-type doping layer can form a tunneling passivation contact structure, and this tunneling passivation contact structure can improve the efficiency of the N-type doping layer in collecting electrons. The thickness of the first passivation layer 18 can be 1 to 3 nm.

[0135] Optionally, the first passivation layer 18 may include a first doped type tunneling layer corresponding to the third doped conductive layer 34 (the first doped type is the same as the doping type of the third doped conductive layer 34), and a second doped type tunneling layer corresponding to the fourth doped conductive layer 35 (the second doped type is the same as the doping type of the fourth doped conductive layer 35).

[0136] Optionally, the third doped conductive layer 34 may be at least one of doped amorphous silicon, doped polycrystalline silicon, doped microcrystalline silicon, and doped silicon carbide. The fourth doped conductive layer 35 may be at least one of doped amorphous silicon, doped polycrystalline silicon, doped microcrystalline silicon, and doped silicon carbide. The thickness of the third doped conductive layer 34 may be 50 - 300 nm. The doping concentration of the third doped conductive layer 34 may be 1×10 17 cm -3 ~1×10 20 cm -3 。 The thickness of the fourth doped conductive layer 35 may be 50 - 300 nm. The doping concentration of the third doped conductive layer 34 may be 1×10 17 cm -3 ~1×10 20 cm -3 。

[0137] Optionally, the first surface has a plurality of the grooves 11. The first surface includes alternately arranged first regions and second regions. The third doped conductive layer 34 is located in the first regions, and the fourth doped conductive layer 35 is located in the second regions. Adjacent first regions and second regions are separated by the grooves 11.

[0138] Optionally, the size of the third doped conductive layer 34 is the same as the size of the first region, and the size of the fourth doped conductive layer 35 is the same as the size of the second region.

[0139] In some embodiments, the size of the third doped conductive layer 34 is larger than the size of the fourth doped conductive layer 35. This can ensure that the back - contact solar cell has good collection effects on both holes and electrons, which is beneficial to improving the performance and conversion efficiency of the back - contact solar cell.

[0140] Optionally, the orthographic projection area of the third electrode 38 on the substrate 10 is smaller than the area of the first region, and this orthographic projection is located in the first region. The orthographic projection area of the fourth electrode 39 on the substrate 10 is smaller than the area of the second region, and this orthographic projection is located in the second region.

[0141] Optionally, along the thickness direction of the substrate 10, the distance between the first region and the second surface is greater than the distance between the second region and the second surface. That is, the fourth doped conductive layer 35 is closer to the second surface than the third doped conductive layer 34, such that the third doped conductive layer 34 and the fourth doped conductive layer 35 are misaligned in the thickness direction of the substrate 10, further reducing the possibility of leakage current between the third doped conductive layer 34 and the fourth doped conductive layer 35, thereby further improving the reliability of the back-contact solar cell, and improving the efficiency and output power of the back-contact solar cell.

[0142] Optionally, the distance between the first region and the second surface is a first distance, the distance between the second region and the second surface is a second distance, the first distance can be 2 to 10 μm; the second distance can be 2 to 10 μm; the difference between the first distance and the second distance can be 1 to 5 μm.

[0143] Optionally, the third passivation layer 36 includes an aluminum oxide layer and a silicon nitride layer stacked in sequence along the direction away from the third doped conductive layer 34 and the fourth doped conductive layer 35. The fourth passivation layer 37 includes an aluminum oxide layer and a silicon nitride layer stacked in sequence along the direction away from the second surface. The thickness of the aluminum oxide layer is 2 to 10 nm. The thickness of the silicon nitride layer is 50 to 150 nm.

[0144] Optionally, as Figure 5 shown, the solar cell may further include: a third antireflection layer 45, located between the third passivation layer 36 and the third electrode 38 and between the third passivation layer 36 and the fourth electrode 39, and covering the surface of the third passivation layer 36 away from the third doped conductive layer 34, the fourth doped conductive layer 35, and the groove 11; a fourth antireflection layer 46, located on the surface of the fourth passivation layer 37 away from the substrate 10.

[0145] An embodiment of the present application further provides a battery structure of a heterojunction solar cell, as Figure 6 shown, the second surface has the groove 11, and the solar cell further includes:

[0146] A fifth doped conductive layer 40, located on the side of the first passivation layer 18 away from the first surface;

[0147] A first transparent conductive layer 25, located on the side of the fifth doped conductive layer 40 away from the first passivation layer 18, on the bottom surface and the side surface of the groove 11 on the first surface;

[0148] A fifth passivation layer 42, located on the second surface;

[0149] The sixth doped conductive layer 41 is located on the side of the fifth passivation layer 42 away from the second surface. The sixth doped conductive layer 41 has the same doping type as the substrate 10, and the sixth doped conductive layer 41 has a different doping type from the fifth doped conductive layer 40;

[0150] The second transparent conductive layer 26 is located on the side of the sixth doped conductive layer away from the fifth passivation layer 42, on the bottom surface and the side surface of the groove on the second surface;

[0151] The fifth electrode 43 is located on the side of the first transparent conductive layer 25 away from the fifth doped conductive layer 40;

[0152] The sixth electrode 44 is located on the side of the second transparent conductive layer 26 away from the sixth doped conductive layer 41.

[0153] In the embodiment, the first passivation layer 18 and the fifth passivation layer 42 are used to passivate the defects on the surface of the substrate 10, thereby reducing carrier recombination; the first transparent conductive layer 25 and the second transparent conductive layer 26 have light transmittance and conductivity, and are used to collect photo-generated carriers and allow sunlight to enter the battery; the sixth doped conductive layer 41 plays a field passivation role; the fifth doped conductive layer 40 and the substrate 10 form a PN junction, and at the same time, it also affects the carrier transport between interfaces.

[0154] In some embodiments, as Figure 6 shown, both the first surface and the second surface of the substrate 10 respectively have microstructures.

[0155] Optionally, the thickness of the first passivation layer 18 and the fifth passivation layer 42 is 1 - 3 nm, and the first passivation layer 18 and the fifth passivation layer 42 can specifically be an intrinsic amorphous silicon layer, without doping.

[0156] Optionally, the thickness of the fifth doped conductive layer 40 is 50 - 300 nm, and the doping concentration is 1×10 17 cm -3 ~1×10 20 cm -3 . The thickness of the sixth doped conductive layer 41 is 50 - 300 nm, and the doping concentration is 1×10 17 cm -3 ~1×10 20 cm -3 .

[0157] Optionally, the materials of the first transparent conductive layer 25 and the second transparent conductive layer 26 are independently selected from one or more of indium tin oxide (ITO) and aluminum zinc oxide. The thickness of the first transparent conductive layer 25 can be 10 - 500 nm. The thickness of the second transparent conductive layer 26 can be 10 - 500 nm.

[0158] Optionally, the grooves 11 on the first surface and the grooves 11 on the second surface are symmetrically distributed along a direction perpendicular to the thickness of the substrate 10.

[0159] Hereinafter, the solar cell of the present application will be specifically described with reference to specific examples and comparative examples.

[0160] Example 1

[0161] This example provides a solar cell, including:

[0162] A substrate, including opposite first and second surfaces, the first surface having grooves, and the first surface outside the periphery of the grooves and the bottom surface of the grooves having a plurality of second conical structures. The side surface of the grooves includes a first buffer zone, a fuzzing zone, and a second buffer zone arranged in sequence along a first direction. The first buffer zone has a plurality of first prisms, the fuzzing zone has a plurality of first conical structures, the second buffer zone has a plurality of second prisms, and the height directions of the first conical structures intersect with the height directions of the second conical structures;

[0163] A first passivation layer, located on the first surface.

[0164] Comparative Example 1

[0165] This comparative example provides a solar cell, and the only difference between this solar cell and Example 1 is that the first surface of the substrate in this comparative example has no grooves, no second conical structures on the bottom surface of the grooves, and no first conical structures, first prisms, and second prisms on the side surface of the grooves.

[0166] Comparative Example 2

[0167] This comparative example provides a solar cell, and the only difference between this solar cell and Example 1 is that this comparative example has no first conical structures, first prisms, and second prisms on the side surface of the grooves.

[0168] The surface reflectivity of the solar cells in Example 1 and Comparative Example 1 was tested, and the test results are shown in Table 1:

[0169] Table 1

[0170]

[0171]

[0172] As can be seen from the experimental data in Table 1, for light rays in the wavelength range of 300 nm to 780 nm, the surface reflectivity of the solar cell of Example 1 is lower than that of Comparative Example 1 and Comparative Example 2, indicating that the technical solution of the present application can improve the light trapping effect of the solar cell.

[0173] An embodiment of the present application further provides a method for manufacturing a solar cell. It should be noted that the method for manufacturing the solar cell is used to manufacture and form any of the above-mentioned solar cells.

[0174] Figure 7 is a flowchart of the method for manufacturing a solar cell according to an embodiment of the present application. Figures 8 to 11 is a schematic structural diagram obtained after each process step according to the method for manufacturing a solar cell. As Figures 7 to 11 shown, the method includes the following steps:

[0175] Step S201, as Figure 8 shown, provide an initial structure, the initial structure includes an initial substrate 29 and an initial passivation layer 32, the initial substrate 29 includes an opposite third surface and a second surface, the third surface has a microstructure, and the initial passivation layer 32 is located on the third surface;

[0176] Step S202, remove a part of the initial passivation layer 32 and a part of the initial substrate 29 to form an initial groove 31 in the initial substrate 29;

[0177] Specifically, the remaining initial passivation layer 32 can form a first passivation layer. The third surface after forming the initial groove 31 serves as the first surface.

[0178] Step S203, as Figure 11 shown, texture the bottom surface and the side surface of the initial groove 31 to form the microstructures on the side surface and the bottom surface of the initial groove 31 respectively. After texturing, the initial groove 31 forms a groove 11, and the remaining initial substrate 29 forms a substrate 10. The plurality of microstructures include: a first conical structure 12, a second conical structure 13, and a columnar structure 14. The height direction of the first conical structure 12 intersects with the height direction of the second conical structure 13, and the side surface of the columnar structure 14 is inclined towards the outer peripheral direction of the groove 11.

[0179] Specifically, the third surface with a groove forms the first surface. The outer peripheral direction of the groove 11, i.e., the direction from the groove 11 to the first surface on the outer periphery of the groove 11, the side surface of the columnar structure 14 being inclined towards the outer peripheral direction of the groove means that the side surface of the columnar structure 14 is not perpendicular to the first surface but has a certain inclination angle relative to the first surface. At least part of the first conical structure 12, the second conical structure 13, and the columnar structure 14 is located on the first surface, at least part of the first conical structure 12, the second conical structure 13, and the columnar structure 14 is located on the bottom surface of the groove, and at least part of the first conical structure 12, the second conical structure 13, and the columnar structure 14 is located on the side surface of the groove. The first conical structure 12 and the second conical structure 13 may specifically be pyramid structures, such as pyramid structures. The columnar structure 14 may specifically be a prism structure. The height direction of the first conical structure 12 may be perpendicular to the height direction of the second conical structure 13. The substrate 10 may be a silicon substrate 10, and the material of the silicon substrate 10 may include single-crystalline silicon, polycrystalline silicon, amorphous silicon, and microcrystalline silicon, etc.

[0180] Through the embodiment, first, an initial substrate and an initial passivation layer located on the third surface of the initial substrate are provided, wherein the third surface has microstructures; then, part of the initial passivation layer and part of the substrate are removed to form an initial groove; finally, the side surface of the initial groove is textured to form microstructures located on the side surface and the bottom surface of the initial groove, and the microstructures include a first conical structure, a second conical structure, and a columnar structure, and the height directions of the first conical structure and the second conical structure are different. The solar cell obtained by the method is provided with microstructures on the surfaces in two intersecting directions, namely the surface and the side surface. Under the combined action of the two groups of microstructures in different directions, light at more angles can be scattered and enter the interior of the solar cell, thereby effectively suppressing the specular reflection effect of light, greatly reducing the light reflection loss, enhancing the light trapping effect, and thus improving the overall light absorption efficiency of the solar cell. Moreover, since multiple microstructures can provide multiple reflection surfaces, the incident light energy can interact with surfaces of multiple angles and curvatures, so that the incident light can be reflected multiple times in different directions, increasing the propagation path length of the light inside the solar cell. The farther the light propagates inside the cell, the more opportunities it has to interact with the cell material, thereby greatly increasing the generation probability of photo-generated carriers and improving the photoelectric conversion efficiency of the cell.

[0181] In some embodiments, the microstructures on the third surface may be the second conical structure 13, and the height direction of the second conical structure 13 intersects (for example, is perpendicular to) the third surface.

[0182] In an alternative solution, texturing is performed on the bottom surface and the side surface of the initial groove 31 to form the microstructures on the side surface and the bottom surface of the initial groove 31 respectively, including: etching the bottom surface and the side surface of the initial groove 31 with a mixed solution at an ambient temperature of 60 to 90 °C to form the microstructures on the side surface and the bottom surface of the initial groove 31 respectively, the mixed solution including an alkaline solution and a texturing additive. In this embodiment, the bottom surface and the side surface of the initial groove 31 are etched with the alkaline solution to form the microstructures, which can increase the complexity of the battery surface topography without damaging the overall structural integrity of the battery. These microstructures can significantly increase the scattering of light on the battery surface, extend the path length of light, thereby increasing the effective absorption of light inside the battery, increasing the short-circuit current, and further improving the overall photoelectric conversion efficiency; moreover, the microstructures obtained after texturing treatment can reduce the direct reflection of light on the battery surface, causing the incident light to be scattered and absorbed at different angles, and the reflectivity is greatly reduced, which helps to improve the light capture rate and the performance of the battery.

[0183] In the present application, the volume of the alkaline solution is 0.5 to 20 L, and the volume of the texturing additive is 0.5 to 10 L.

[0184] In some embodiments, etching the bottom surface and the side surface of the initial groove 31 with a mixed solution to form the microstructures on the side surface and the bottom surface of the initial groove 31 respectively, including: etching the bottom surface and the side surface of the initial groove 31 with a mixed solution to form a plurality of first prisms 16, a plurality of first conical structures 12 and a plurality of second prisms 17 on the side surface of the initial groove 31, the plurality of first prisms 16 being located in a first buffer zone, the plurality of first conical structures 12 being located in a linting zone, the plurality of second prisms 17 being located in a second buffer zone, the first buffer zone, the linting zone and the second buffer zone being arranged in sequence along a first direction on the side surface of the groove, the first direction being perpendicular to the first surface and pointing from the first surface to the second surface, the height direction of the first conical structure 12 intersecting (for example, being perpendicular to) the first direction, and forming the second conical structure 13 on the bottom surface of the initial groove 31, the height direction of the second conical structure 13 being parallel to the first direction or intersecting the first direction.

[0185] In other embodiments, the initial structure further includes an initial doped conductive layer 30 located in the initial substrate 29, the initial doped conductive layer 30 being in contact with the initial passivation layer 32, removing a part of the initial passivation layer 32 and a part of the initial substrate 29 to form an initial groove 31 in the initial substrate 29, including: as Figure 8 and Figure 9As shown, a part of the initial passivation layer 32 is removed by a laser etching process, so that a part of the initial doped conductive layer 30 is exposed, and the remaining initial passivation layer 32 forms an oxide layer 33; as Figure 9 and Figure 10 As shown, the exposed initial doped conductive layer 30 and the exposed initial substrate 29 are sequentially removed by a wet etching process to obtain the initial groove 31. In this embodiment, first, a part of the initial passivation layer 32 is removed by a laser etching method. Laser etching can accurately control the initial passivation layer 32 to be removed, forming a high-precision and localized structure, avoiding damage to other parts of the battery; then, the exposed part of the initial doped conductive layer 30 and part of the initial substrate 29 are sequentially removed by a wet etching method, and an initial groove 31 with a better morphology can be obtained, which is convenient for forming microstructures with better morphology on the side and bottom surfaces of the initial groove 31; the combined use of laser etching and wet etching can achieve the precise manufacturing of complex structures while controlling costs, reduce material waste, and improve the economic benefits of the entire battery manufacturing process.

[0186] In addition, the doping type of the initial doped conductive layer 30 is different from the doping type of the initial substrate 29. Removing a part of the initial doped conductive layer 30 reduces the carrier recombination caused by the doping of foreign elements and can improve the open-circuit voltage of the battery.

[0187] In order to further achieve precise localized removal of the initial passivation layer 32, according to some further alternative solutions of the present application, removing a part of the initial passivation layer 32 by a laser etching process includes: using a laser beam with an output power of 10~90% of the maximum output power and a scanning speed of 5000~40000 mm / s to etch and remove a part of the initial passivation layer 32, and the laser beam includes one of the following: an infrared laser beam, an ultraviolet laser beam, and a green laser beam. In this embodiment, within the specified power and speed range, the laser can accurately remove the initial passivation layer 32 in a preset area without affecting the surrounding area, avoiding structural damage caused by over-etching, maintaining the integrity and flatness of the battery surface, and being beneficial to subsequent processes; laser etching with an output power in the range of 10~90% can ensure the rapid and efficient removal of the initial passivation layer 32, and the control of the scanning speed can further optimize the etching time and accuracy; by using an infrared, ultraviolet, or green laser beam, the most suitable wavelength can be selected according to the absorption characteristics of the material, thereby minimizing the heat-affected zone, reducing the thermal damage to the battery surface, and maintaining the high quality and performance stability of the battery surface.

[0188] In an exemplary embodiment, as Figure 8 and Figure 9As shown, the remaining initial doped conductive layer 30 forms a first doped conductive layer 15. The oxide layer 33 is a borosilicate glass layer. After texturing the bottom surface and side surfaces of the initial groove 31, the method further includes: forming a silicon oxide layer on the bottom surface and side surfaces of the groove by an oxidation process; forming an aluminum oxide layer on the surface of the borosilicate glass layer away from the first doped conductive layer and on the surface of the silicon oxide layer away from the bottom surface and side surfaces of the groove; forming an antireflection layer on the surface of the aluminum oxide layer away from the borosilicate glass layer and the silicon oxide layer to obtain a first passivation layer, that is, the first passivation layer includes the borosilicate glass layer, the silicon oxide layer, the aluminum oxide layer, and the antireflection layer. By sequentially forming a silicon oxide layer, an aluminum oxide layer, and an antireflection layer on the surface of the initial groove after texturing, not only can the surface passivation and light trapping effects be enhanced, and the contact performance be improved, but also the mechanical strength and chemical stability of the cell are increased due to the formation of the silicon oxide layer and the aluminum oxide layer, so the structural stability and quality can also be increased.

[0189] In addition, as Figure 8 shown, the second surface of the initial substrate 29 also has a microstructure. In some embodiments, the second surface of the initial substrate 29 has a second conical structure 13; a second doped conductive layer 20 and a second passivation layer 21 are sequentially stacked on the second surface of the initial substrate 29. The doping type of the second doped conductive layer 20 is the same as the doping type of the initial substrate 29 and different from the doping type of the first doped conductive layer 15.

[0190] The principle of etching the side surface of the initial groove to form a textured surface is explained below: The single-crystalline silicon crystal structure is as Figure 12 shown. There are three crystal orientations in single-crystalline silicon: 100, 110, and 111. The three crystal orientation structures are as Figure 13 shown. The relationship of the atomic density of the three crystal orientation structures of single-crystalline silicon is: 111>110>100. Therefore, the relationship of the reaction rates of the three crystal orientation structures of single-crystalline silicon with alkali is: 111<110<100. During the wet etching of the bottom surface and side surfaces of the initial groove 31 using a mixed solution, anisotropic etching of single-crystalline silicon can be performed by adjusting the etching conditions, and the 111 crystal orientation can be exposed. It can be considered that the 111 crystal orientations of multiple adjacent unit cells of single-crystalline silicon form a rhombus structure, as Figure 14 shown. During conventional texturing (i.e., etching to form the second conical structure), the top of the upper pyramid will be exposed (as Figure 15 shown). If there is a vertical plane with a certain width at the same time, pyramid structures will grow on the planes in both the horizontal and vertical directions. The exposed 111 crystal orientations are the tips on different sides of the rhombus, thereby obtaining the first conical structure on the side surface of the groove.

[0191] An embodiment of the present application further provides a photovoltaic module, including any one of the above-described solar cells.

[0192] The photovoltaic module includes any one of the above-described solar cells. In this solar cell, there are grooves on the first surface of the substrate, and microstructures are provided on the first surface of the substrate, on the bottom surface of the grooves, and on the side surfaces of the grooves. The microstructures include a first conical structure, a second conical structure, and a columnar structure, and the height directions of the first conical structure and the second conical structure are different. That is to say, the solar cell of the present application is provided with microstructures on the surfaces in two intersecting directions, namely the surface and the side surface. Under the combined action of the two groups of microstructures in different directions, light at more angles can be scattered and enter the interior of the solar cell, thereby effectively suppressing the specular reflection effect of light, greatly reducing the light reflection loss, enhancing the light trapping effect, and thus improving the overall light absorption efficiency of the solar cell. Moreover, the incident light is reflected multiple times in different directions, increasing the propagation path length of the light inside the solar cell. The farther the light travels inside the cell, the more opportunities it has to interact with the cell material, thereby significantly increasing the generation probability of photo-generated carriers and improving the photoelectric conversion efficiency of the cell.

[0193] It should also be noted that the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, such that a process, method, article or apparatus comprising a series of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article or apparatus. Without further limitation, an element defined by the phrase "comprising an..." does not exclude the presence of additional identical elements in the process, method, article or apparatus comprising the element.

[0194] From the above description, it can be seen that the embodiments described in the present application achieve the following technical effects:

[0195] In the solar cell of the present application, there are grooves on the first surface of the substrate, and microstructures are provided on the first surface of the substrate, on the bottom surface of the grooves, and on the side surfaces of the grooves. The plurality of microstructures include a first conical structure, a second conical structure, and a columnar structure, and the height directions of the first conical structure and the second conical structure are different. That is to say, the solar cell of the present application is provided with microstructures on the surfaces in two intersecting directions, namely the surface and the side surface. Under the combined action of the two groups of microstructures in different directions, light at more angles can be scattered and enter the interior of the solar cell, thereby effectively suppressing the specular reflection effect of light, greatly reducing the light reflection loss, enhancing the light trapping effect, and thus improving the overall light absorption efficiency of the solar cell. Moreover, since a variety of microstructures can provide a variety of reflection surfaces, the incident light energy can interact with surfaces of various angles and curvatures, so that the incident light can be reflected multiple times in different directions, increasing the propagation path length of the light in the solar cell. The farther the light propagates in the cell, the more opportunities it has to interact with the cell material, thereby greatly increasing the generation probability of photo-generated carriers and improving the photoelectric conversion efficiency of the cell.

[0196] The foregoing is only the preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included within the protection scope of the present application.

Claims

1. A solar cell, characterized in that: include: A substrate, comprising a first surface and a second surface opposite to each other, the first surface having a groove, the first surface at the periphery of the groove, the bottom surface of the groove, and the side surface of the groove respectively having microstructures, wherein the plurality of microstructures comprise: a first cone structure, a second cone structure, and a columnar structure, wherein the height direction of the first cone structure intersects the height direction of the second cone structure, and the side surface of the columnar structure is inclined toward the periphery of the groove; A first passivation layer is located on the first surface.

2. The solar cell according to claim 1, characterized in that The columnar structure includes a first prism and a second prism, the plane where the side of the first prism is located intersects with the plane where the side of the second prism is located, the side of the groove includes a first buffer zone, a pile outlet zone and a second buffer zone arranged in sequence along a first direction, the first prism is located in the first buffer zone, the first conical structure is located in the pile outlet zone, the second prism is located in the second buffer zone, and the first direction is perpendicular to the first surface and points from the first surface to the second surface.

3. The solar cell according to claim 2, characterized in that: The angle between the first surface and the side surface of the first prism is an acute angle.

4. The solar cell according to claim 2, characterized in that: The included angle between the bottom surface of the groove and the side surface of the second prism is an obtuse angle.

5. The solar cell according to claim 2, characterized in that: The height of the first prism in the first direction is 0.5-2 μm.

6. The solar cell according to claim 2, characterized in that: The height of the second prism in the first direction is 0.5-5 μm.

7. The solar cell according to claim 2, characterized in that: The height of the first prism in the second direction is 0.5-2 μm. The second direction is perpendicular to the first direction and the first intersection direction. The first intersection direction is the extension direction of the intersection of the side surface of the first prism and the first surface.

8. The solar cell according to claim 2, characterized in that: The height of the second prism in the third direction is 0.5-2 μm, and the third direction is perpendicular to the first direction and the second intersection direction, and the second intersection direction is the extension direction of the intersection line of the side surface of the first prism and the bottom surface of the groove.

9. The solar cell according to claim 1, characterized in that: The depth of the groove in the fourth direction is 10-100 μm, the width of the groove in the fifth direction is 3-10 μm, the fourth direction is perpendicular to the first surface, and the fifth direction is perpendicular to the fourth direction.

10. The solar cell according to claim 1, characterized in that: The height of the first cone-shaped structure is 0.5-3 μm.

11. The solar cell according to claim 1, characterized in that: The second cone-shaped structure is located on the bottom surface of the groove and on the first surface.

12. The solar cell according to claim 11, characterized in that: The protruding height of the second cone structure on the bottom surface of the groove is a first height, and the protruding height of the second cone structure on the first surface is a second height, and the first height is smaller than the second height.

13. The solar cell according to claim 1, characterized in that The first passivation layer is also located on the bottom surface of the groove and the side surface of the groove, and the solar cell further includes: A first doped conductive layer, located in the substrate and in contact with the first passivation layer, wherein a surface of the first doped conductive layer away from the second surface is a portion of the first surface; a tunneling oxide layer located on the second surface; A second doped conductive layer, located on a side of the tunnel oxide layer away from the substrate, the second doped conductive layer and the substrate have the same doping type, and the second doped conductive layer and the first doped conductive layer have a different doping type; a second passivation layer, located on a side of the second doped conductive layer away from the tunnel oxide layer; a first electrode, located on a side of the first passivation layer away from the first doped conductive layer; The second electrode is located on a side of the second passivation layer away from the second doped conductive layer.

14. The solar cell according to claim 1, characterized in that The first passivation layer is located on the first surface of the outer periphery of the groove, and the solar cell further comprises: a third doped conductive layer located on a side of the groove and away from the first surface; a fourth doped conductive layer located on a side of the first passivation layer on the other side of the groove away from the first surface, the fourth doped conductive layer having the same doping type as the substrate, and the third doped conductive layer and the fourth doped conductive layer having different doping types; A third passivation layer is located on a side of the third doped conductive layer and the fourth doped conductive layer away from the first passivation layer, a bottom surface of the groove, and a side surface of the groove; a fourth passivation layer, located on the second surface; a third electrode, located at a side of the third passivation layer away from the third doped conductive layer; The fourth electrode is located on a side of the third passivation layer away from the fourth doped conductive layer.

15. The solar cell according to claim 1, characterized in that The second surface has the groove, and the solar cell further comprises: a fifth doped conductive layer, located on a side of the first passivation layer away from the first surface; A first transparent conductive layer is located on a side of the fifth doped conductive layer away from the first passivation layer and on a bottom surface and a side surface of the groove on the first surface; a fifth passivation layer, located on the second surface; a sixth doped conductive layer, located on a side of the fifth passivation layer away from the second surface, the sixth doped conductive layer having the same doping type as the substrate, and a different doping type from the fifth doped conductive layer; a second transparent conductive layer, located on a side of the sixth doped conductive layer away from the fifth passivation layer, and on a bottom surface and a side surface of the groove on the second surface; A fifth electrode, located on a side of the first transparent conductive layer away from the fifth doped conductive layer; The sixth electrode is located on a side of the second transparent conductive layer away from the sixth doped conductive layer.

16. The solar cell according to claim 13, characterized in that: The first passivation layer comprises: a borosilicate glass layer, located on a surface of the first doped conductive layer away from the second surface; a silicon oxide layer, located on the bottom surface of the groove and the side surface of the groove; an aluminum oxide layer, located on a side of the borosilicate glass layer away from the first doped conductive layer, and located on a side of the silicon oxide layer away from the bottom surface of the groove and the side surface of the groove; The anti-reflection layer is located on a side of the aluminum oxide layer away from the borosilicate glass layer and the silicon oxide layer.

17. The solar cell according to claim 16, characterized in that: The thickness of the silicon oxide layer is 50-150 nm.

18. A method for manufacturing a solar cell, characterized in that: include: Providing an initial structure, the initial structure comprising an initial substrate and an initial passivation layer, the initial substrate comprising a third surface and a second surface opposite to each other, the third surface having a microstructure, and the initial passivation layer being located on the third surface; removing a portion of the initial passivation layer and a portion of the initial substrate to form an initial groove in the initial substrate; The bottom surface and the side surface of the initial groove are textured to form the microstructure on the side surface and the bottom surface of the initial groove respectively. The initial groove after textured forms a groove, and the remaining initial substrate forms a substrate. The multiple microstructures include: a first conical structure, a second conical structure and a columnar structure. The height direction of the first conical structure intersects with the height direction of the second conical structure, and the side surface of the columnar structure is inclined toward the outer peripheral direction of the groove.

19. The method for manufacturing a solar cell according to claim 18, characterized in that: The bottom surface and the side surface of the initial groove are textured to form the microstructure on the side surface and the bottom surface of the initial groove, respectively, including: At an ambient temperature of 60-90° C., a mixed solution is used to etch the bottom and side surfaces of the initial groove to form the microstructure on the side and bottom surfaces of the initial groove, respectively. The mixed solution includes an alkaline solution and a texturing additive.

20. The method for manufacturing a solar cell according to claim 19, characterized in that: The capacity of the alkaline solution is 0.5-20L, and the capacity of the texturing additive is 0.5-10L.

21. The method for manufacturing a solar cell according to claim 18, characterized in that: The initial structure further includes an initial doped conductive layer located in the initial substrate, the initial doped conductive layer is in contact with the initial passivation layer, and a portion of the initial passivation layer and a portion of the initial substrate are removed to form an initial groove located in the initial substrate, including: Using a laser etching process to remove part of the initial passivation layer, so that part of the initial doped conductive layer is exposed, and the remaining initial passivation layer forms an oxide layer; The exposed initial doped conductive layer and the exposed initial substrate are removed in sequence by a wet etching process to obtain the initial groove.

22. The method for manufacturing a solar cell according to claim 21, characterized in that: Removing part of the initial passivation layer by a laser etching process comprises: A laser beam having an output power of 10-90% of the maximum output power and a scanning speed of 5000-40000 mm / s is used to etch and remove part of the initial passivation layer, wherein the laser beam includes one of the following: an infrared laser beam, an ultraviolet laser beam, and a green laser beam.

23. The method for manufacturing a solar cell according to claim 21, characterized in that: The remaining initial doped conductive layer forms a first doped conductive layer, the oxide layer is a borosilicate glass layer, and after texturing the bottom and side surfaces of the initial groove, the method further includes: Forming a silicon oxide layer on the bottom surface of the groove and the side surface of the groove by an oxidation process; forming an aluminum oxide layer on a surface of the borosilicate glass layer away from the first doped conductive layer, and on a surface of the silicon oxide layer away from the bottom surface of the groove and the side surface of the groove; An anti-reflection layer is formed on the surface of the aluminum oxide layer away from the borosilicate glass layer and the silicon oxide layer to obtain a first passivation layer.

24. A photovoltaic module, characterized in that: A solar cell comprising the solar cell according to any one of claims 1 to 17.

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