Photovoltaic cell, module, and system

Abstract

The present disclosure is applicable to the technical field of solar cells, and provides a photovoltaic cell, a module, and a system. A plurality of first textured structures and a plurality of second textured structures are formed in a middle region and an edge region of the cell, respectively. The second textured structures and the first textured structures are each tapered, and the vertex angles of the second textured structures having a first preset proportion are greater than the vertex angles of the first textured structures.

Description

Photovoltaic cells, modules and systems

[0001] Cross-references

[0002] This disclosure incorporates, in its entirety, Chinese Patent Application No. 202520172966.7, filed on January 24, 2025, entitled “A Solar Cell, Battery Module and Photovoltaic System,” which is incorporated herein by reference. Technical Field

[0003] This disclosure pertains to the field of solar cell technology, and particularly relates to a solar cell, a cell module, and a photovoltaic system. Background Technology

[0004] Solar cell power generation is a sustainable and clean energy source that converts sunlight into electricity using the photovoltaic effect of semiconductor pn junctions. In related technologies, solar cells are typically textured to reduce reflection and passivate the image. However, current textured surfaces struggle to balance anti-reflection and passivation, resulting in relatively poor photoelectric conversion efficiency.

[0005] Therefore, how to design the textured surface of solar cells to improve photoelectric conversion efficiency has become an urgent problem to be solved.

[0006] Public content

[0007] This disclosure provides a solar cell, a cell module, and a photovoltaic system aimed at solving the problem of how to design the textured surface of a solar cell to improve photoelectric conversion efficiency.

[0008] The solar cell disclosed herein includes two opposing surfaces and several side surfaces, with the side surfaces located between the two opposing surfaces; at least one surface is formed with a central region and an edge region, with the edge region surrounding the central region; the central region and the edge region are respectively formed with several first textured structures and several second textured structures; the second textured structures and the first textured structures are conical in shape, with the apex angle of the second textured structure being greater than the apex angle of the first textured structure in a first preset proportion.

[0009] In some implementations, the first preset ratio is 50%-100%.

[0010] In some implementations, the difference between the maximum value of the apex angle of the second velvet structure and the maximum value of the apex angle of the first velvet structure is 0.5°-15°.

[0011] In some embodiments, at least a portion of the second velvet structure has an apex angle of 75°-85° and at least a portion of the first velvet structure has an apex angle of 70°-82°, or at least a portion of the second velvet structure has an apex angle of 75°-85°, or at least a portion of the first velvet structure has an apex angle of 70°-82°.

[0012] In some embodiments, the surface includes several edges, and the ratio of the width of the edge region to the width of the surface is 1:(5-100).

[0013] In some implementations, the edge region is ring-shaped and continuously surrounds the central region.

[0014] In some embodiments, the size of the second velvet structure in the second preset ratio is smaller than the size of the first velvet structure.

[0015] In some implementations, the second preset ratio is 50%-100%.

[0016] In some implementations, the size difference between the largest second velvet structure and the largest first velvet structure is 0.01 μm to 3.7 μm.

[0017] The battery assembly disclosed herein includes any of the solar cells described above.

[0018] The photovoltaic system disclosed herein includes any of the aforementioned battery modules.

[0019] The solar cells, battery modules, and photovoltaic systems of the present disclosure, since the apex angle of the second textured structure located in the edge region is larger than the apex angle of the first textured structure located in the middle region, can achieve better passivation effect of the second textured structure and better anti-reflection effect of the first textured structure, which is beneficial to improving the photoelectric conversion efficiency of the solar cells as a whole. Attached Figure Description

[0020] Figure 1 is a schematic diagram of the structure of a solar cell according to an embodiment of the present disclosure;

[0021] Figure 2 is a schematic diagram of the structure of a solar cell according to an embodiment of the present disclosure;

[0022] Figure 3 is a schematic diagram of a partial structure of a solar cell according to an embodiment of the present disclosure;

[0023] Figure 4 is an SEM image of the middle region of a solar cell according to an embodiment of the present disclosure;

[0024] Figure 5 is an SEM image of the middle region of a solar cell according to an embodiment of the present disclosure;

[0025] Figure 6 is an SEM image of the edge region of a solar cell according to an embodiment of the present disclosure;

[0026] Figure 7 is an SEM image of the edge region of a solar cell according to an embodiment of the present disclosure;

[0027] Explanation of key component symbols: 10, Solar cell; 11, Surface; 110, Edge; 111, Middle region; 112, Edge region; 12, Side; 131, First textured structure; α1, Vertex angle of the first textured structure; d1, Dimension of the first textured structure; 132, Second textured structure; α2, Vertex angle of the second textured structure; d2, Dimension of the second textured structure. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of this disclosure clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. Examples of embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this disclosure, and should not be construed as limiting this disclosure. Furthermore, it should be understood that the specific embodiments described herein are merely for explaining this disclosure and are not intended to limit this disclosure.

[0029] In the description of this disclosure, it should be understood that the terms “length”, “width”, “upper”, “lower”, “left”, “right”, “horizontal”, “top”, “bottom”, etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this disclosure and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this disclosure.

[0030] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, features defined as "first" or "second" may explicitly or implicitly include one or more features. In the description of this disclosure, "a plurality of" means two or more, unless otherwise explicitly defined in some embodiments.

[0031] In the description of this disclosure, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linkage" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this disclosure according to the specific circumstances.

[0032] In this disclosure, unless otherwise expressly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0033] The following disclosure provides numerous different embodiments or examples for implementing various structures of this disclosure. To simplify the disclosure, specific examples of components and arrangements are described below. These are merely examples and are not intended to limit the scope of this disclosure. Furthermore, reference numerals and / or letters may be repeated in different examples; such repetition is for simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or arrangements discussed. In addition, various specific examples of processes and materials are provided in this disclosure, but those skilled in the art will recognize the application of other processes and / or the use of other materials.

[0034] Please refer to Figures 1, 2, 3, 4, 5, 6, and 7. The solar cell 10 of this embodiment includes two opposing surfaces 11 and a plurality of side surfaces 12, with the side surfaces 12 located between the opposing surfaces 11. At least one surface 11 has a central region 111 and an edge region 112, with the edge region 112 surrounding the central region 111. The central region 111 and the edge region 112 are respectively formed with a plurality of first textured structures 131 and a plurality of second textured structures 132. The second textured structures 132 and the first textured structures 131 are conical, and the apex angle α2 of the second textured structure 132 is greater than the apex angle α1 of the first textured structure 131.

[0035] In the solar cell 10 of this disclosure, since the apex angle of the second textured structure 132 located in the edge region 112 is larger than the apex angle of the first textured structure 131 located in the middle region 111, the passivation effect of the second textured structure 132 is better, and the anti-reflection effect of the first textured structure 131 is better, which is beneficial to improving the photoelectric conversion efficiency of the solar cell 10 as a whole.

[0036] It is understandable that a larger apex angle of the textured surface structure results in better passivation, but a worse anti-reflection effect. In the solar cell 10 of this embodiment, a second textured surface structure 132 with a larger apex angle is provided in the edge region 112, where damage and recombination are greater and better passivation is required, which can better passivate the edge region 112; at the same time, a first textured surface structure 131 with a smaller apex angle is provided in the middle region 111, where damage and recombination are relatively less, which can make the anti-reflection effect of the middle region 111 better. Thus, overall, the photoelectric conversion efficiency of the solar cell 10 is better.

[0037] In some embodiments, the solar cell 10 may be a PERC cell, HJT cell, TopCon cell, MWT cell, BC cell, tandem cell, etc. The solar cell 10 may be a back-contact cell or a bi-faced contact cell. The specific form of the solar cell 10 is not limited here.

[0038] In some embodiments, the number of sides 12 can be 1, 2, 3, 4, 5, or other numbers. In the example of Figure 1, the number of sides 12 is 4. In the example of Figure 2, the number of sides 12 is 8. The specific number of sides 12 is not limited here.

[0039] In some embodiments, side surface 12 may also include a central region and an edge region, with the edge region surrounding the central region. The central region and the edge region are each formed with two conical pile surfaces, and the apex angle of the pile surface in the edge region is larger than the apex angle of the pile surface in the central region in a predetermined proportion. That is to say, the explanation and description of the central region 111 and the edge region 112 of surface 11 can be applied to side surface 12. To avoid redundancy, further details are omitted here.

[0040] In some implementations, in some examples, one of the two surfaces 11 is formed with a central region 111 and an edge region 112. In other examples, both surfaces 11 are formed with a central region 111 and an edge region 112.

[0041] In some embodiments, the edge region 112 surrounds the central region 111. This can mean that the edge region 112 is in a ring shape and continuously surrounds the central region 111. Alternatively, it can mean that there are multiple edge regions 112, dispersedly surrounding the central region 111.

[0042] In some embodiments, the number of first pile structures 131 can be 1, 2, 3, 4, 5, or other numbers. The number of second pile structures 132 can be 1, 2, 3, 4, 5, or other numbers. No limitation is made here.

[0043] In some embodiments, "conical" refers to a textured surface that resembles a cone or pyramid. For example, it could be pyramidal. In some embodiments, the dimension of the textured surface refers to the width of the base of the cone. For example, the width of the base of a pyramid. It is understood that when the base is irregular in shape, the dimension can refer to the maximum width of the base or the width at any point on the base. The width at any point on the base refers to the distance between that point and its opposite side.

[0044] In some implementations, the apex angle refers to the included angle between two opposite sides 12 of the velvet structure.

[0045] In some embodiments, the first preset ratio is 50%-100%. For example, it is 50%, 52%, 60%, 80%, 90%, or 100%. This ensures that the proportion of the second textured structure 132 with larger apex angles is within a suitable range, avoiding a poor passivation effect in the edge region 112 caused by a small proportion of the second textured structure 132 with larger apex angles, and thus ensuring the passivation effect of the edge region 112 of the solar cell 10.

[0046] In some implementations, the first preset ratio is 80%-90%, such as 80%, 82%, 85%, 88%, or 90%. This further optimizes the ratio of the second velvet structure 132 with a larger apex angle, ensuring the passivation effect of the edge region 112 while allowing space for the existence of the second velvet structure 132 with a smaller apex angle, thus reducing the difficulty of the process.

[0047] Please refer to Figures 3, 5, and 7. In some embodiments, the difference between the maximum value of the apex angle α2 of the second velvet structure 132 and the maximum value of the apex angle α1 of the first velvet structure 131 is 0.5°-15°. For example, it is 0.5°, 0.6°, 1°, 3°, 5°, 10°, 12°, or 15°.

[0048] In this way, the difference between the maximum value of the apex angle of the second velvet structure 132 and the first velvet structure 131 is within a suitable range, thereby avoiding poor passivation effect of the edge region 112 or poor anti-reflection effect of the middle region 111 due to a small difference, and also avoiding the high process difficulty and low production efficiency due to a large difference.

[0049] Referring to Figures 3 and 5, in some embodiments, the apex angle α1 of at least a portion of the first velvet structure 131 is 70°-82°. For example, it is 70°, 71°, 75°, 78°, 80°, or 82°.

[0050] In this way, the apex angle α1 of the first velvet structure 131 is within a suitable range, which can avoid the poor passivation effect caused by the small apex angle α1 of the first velvet structure 131, which cannot meet the basic passivation requirements of the middle region 111, and can also avoid the poor anti-reflection effect caused by the large apex angle α1 of the first velvet structure 131.

[0051] In some embodiments, the apex angle α1 of a portion of the first pile structure 131 may be 70°-82°. For example, the apex angle α1 of the largest first pile structure 131 may be 70°-82°. Alternatively, the apex angle α1 of all the first pile structures 131 may be 70°-82°. No limitation is made here.

[0052] In some embodiments, the apex angle α1 of the first textured structure 131 is 73.9°-79.8°. For example, it is 73.9°, 74°, 75°, 78°, 79.8°, or 80°. In this way, the apex angle α1 of the first textured structure 131 is further optimized, and the overall photoelectric conversion efficiency of the battery is further improved.

[0053] Referring to Figures 3 and 7, in some embodiments, the apex angle α2 of at least a portion of the second velvet structure 132 is 75°-85°. For example, it is 75°, 76°, 78°, 80°, 82°, or 85°.

[0054] In this way, the apex angle α2 of the second velvet structure 132 is within a suitable range, which can avoid the poor passivation effect caused by a small apex angle α2 of the second velvet structure 132, and also avoid the poor anti-reflection effect caused by a large apex angle α2 of the second velvet structure 132, which would fail to meet the basic anti-reflection requirements of the edge region 112.

[0055] In some embodiments, the apex angle α2 of a portion of the second pile structure 132 may be 75°-85°. For example, the apex angle α2 of the largest second pile structure 132 may be 75°-85°. Alternatively, the apex angle α2 of all the second pile structures 132 may be 75°-85°. No limitation is made here.

[0056] In some embodiments, the apex angle α2 of the second textured structure 132 is 80.44°-82.57°. For example, it is 80.44°, 80.5°, 80.8°, 81°, 81.5°, 82°, or 82.57°. This further optimizes the apex angle α2 of the second textured structure 132, further improving the overall photoelectric conversion efficiency of the battery.

[0057] Please refer to Figures 1 and 2. In some embodiments, the surface 11 includes a plurality of edges 110, and the ratio of the width w1 of the edge region 112 to the width w0 of the surface is 1:(5-100). For example, it is 1:5, 1:8, 1:10, 1:30, 1:50, 1:80, 1:90, or 1:100.

[0058] This ensures that the ratio of the width w1 of the edge region 112 to the width w0 of the surface is within a suitable range. It avoids the poor overall passivation effect caused by an excessively small width, and also avoids the passivation effect from diminishing as the width continues to increase. This, in turn, helps to improve the overall photoelectric conversion efficiency of the solar cell 10.

[0059] In some embodiments, the width of the edge region 112 and the width of the surface 11 are the dimensions of the edge region 112 and the surface 11 in the same direction, respectively.

[0060] Please refer to Figures 1 and 2. In some embodiments, the edge region 112 is ring-shaped and continuously surrounds the central region 111.

[0061] Thus, by setting the edge region 112 as a ring, the area near all edges 110 of the surface 11 is provided with a second textured surface structure 132 with a large apex angle, thereby ensuring that all edges 110 of the surface 11 are well passivated without omissions or gaps, which is beneficial to improving the photoelectric conversion efficiency of the solar cell 10.

[0062] Please refer to Figures 3, 4, 5, 6, and 7. In some embodiments, the size d2 of the second velvet structure 132 with the second preset ratio is smaller than the size d1 of the first velvet structure 131.

[0063] This results in a smaller size for at least a portion of the second textured structure 132 located in the edge region 112, thus improving the passivation effect of the second textured structure 132. Simultaneously, a larger size for at least a portion of the first textured structure 131 in the middle region 111 improves the anti-reflection effect of the middle region 111, allowing more sunlight to enter the middle region 111 of the solar cell 10. This, in turn, helps to improve the photoelectric conversion efficiency of the solar cell 10.

[0064] As mentioned earlier, "conical" refers to a textured surface that resembles a cone or pyramid. For example, it could be pyramidal. In some implementations, the dimension of the textured surface refers to the width of the base of the cone, such as the base width of a pyramid. It is understood that when the base shape is irregular, the dimension can refer to the maximum width of the base or the width at any point on the base.

[0065] In some embodiments, the second preset ratio is 50%-100%. For example, it is 50%, 52%, 60%, 80%, 90%, or 100%. This ensures that the proportion of the smaller second textured structure 132 is within a suitable range, avoiding poor passivation of the edge region 112 due to the smaller proportion of the second textured structure 132, and thus ensuring the passivation effect of the edge region 112 of the solar cell 10.

[0066] In some embodiments, the second preset ratio is 80%-90%. For example, it is 80%, 82%, 85%, 88%, or 90%. In this way, the ratio of the smaller second velvet structure 132 is further optimized, which ensures the passivation effect of the edge region 112 while allowing space for the larger second velvet structure 132, thereby reducing the difficulty of the process.

[0067] Please refer to Figures 3, 4, 5, 6, and 7. In some embodiments, the difference between the size d2 of the largest second velvet structure 132 and the size d1 of the largest first velvet structure 131 is 0.01 μm to 3.7 μm. For example, it is 0.01 μm, 0.02 μm, 0.1 μm, 0.5 μm, 1 μm, 2 μm, 3 μm, 3.5 μm, or 3.7 μm.

[0068] In this way, the difference between the size d2 of the largest second velvet structure 132 and the size d1 of the largest first velvet structure 131 is within a suitable range. This avoids the poor passivation effect of the edge region 112 or the poor anti-reflection effect of the middle region 111 caused by the difference being too small, and also avoids the high process difficulty and low production efficiency caused by the difference being too large.

[0069] In some embodiments, the size d1 of at least a portion of the first textured structure 131 is 0.3 μm-4 μm. For example, it is 0.3 μm, 0.5 μm, 0.8 μm, 1 μm, 2 μm, 2.818 μm, 3 μm, 3.8 μm, or 4 μm. This ensures that the size d1 of the first textured structure 131 is within a suitable range, avoiding poor anti-reflection performance due to an excessively small size, and also avoiding failure to meet the basic anti-reflection requirements of the intermediate region 111 due to an excessively large size. In some embodiments, the size d1 of the first textured structure 131 is 2.818 μm.

[0070] In some embodiments, the size d1 of a portion of the first velvet structure 131 may be 0.3 μm-4 μm. For example, the size d1 of the largest first velvet structure 131 may be 0.3 μm-4 μm. Alternatively, the size d1 of all the first velvet structures 131 may be 0.3 μm-4 μm.

[0071] In some embodiments, the size d2 of the second textured structure 132 is 0.3μm-3μm. For example, it is 0.3μm, 0.5μm, 0.8μm, 1μm, 1.63μm, 2μm, 2.818μm, or 3μm. This ensures that the size d2 of the second textured structure 132 is within a suitable range, avoiding the inability to meet the basic anti-reflection requirements of the edge region 112 due to an excessively small size, and also avoiding poor passivation effect due to an excessively large size. In some embodiments, the size d2 of the second textured structure 132 is 1.63μm.

[0072] The battery assembly of this disclosure includes the solar cell 10 of any of the above-mentioned embodiments.

[0073] In the battery module of this embodiment, since the apex angle of the second textured structure 132 located in the edge region 112 of the solar cell 10 is larger than the apex angle of the first textured structure 131 located in the middle region 111, the passivation effect of the second textured structure 132 is better, and the anti-reflection effect of the first textured structure 131 is better, which is beneficial to improving the photoelectric conversion efficiency of the solar cell 10 overall.

[0074] In this embodiment, multiple solar cells 10 in the battery module can be connected in series to form a battery string, thereby realizing the series current collection and output. For example, the battery cells can be connected in series by setting solder strips (busbars, interconnecting strips), conductive backplates, etc.

[0075] It is understood that in such embodiments, the battery assembly may also include a metal frame, a backsheet, photovoltaic glass, and an encapsulating film. The encapsulating film may be filled between the front and back of the solar cell 10, the photovoltaic glass, adjacent cells, etc. As a filler, it may be a transparent colloid with good light transmittance and aging resistance. For example, the encapsulating film may be an EVA film or a POE film, and the specific choice can be made according to the actual situation, without limitation.

[0076] Photovoltaic glass can be applied to the encapsulating film on the front side of the solar cell 10. This photovoltaic glass can be ultra-clear glass, possessing high light transmittance, high transparency, and superior physical, mechanical, and optical properties. For example, ultra-clear glass can achieve a light transmittance of over 92%, protecting the solar cell 10 while minimizing impact on its efficiency. Simultaneously, the encapsulating film bonds the photovoltaic glass and the solar cell 10 together, providing sealing, insulation, and waterproofing / moisture protection for the solar cell 10.

[0077] The backsheet can be attached to the encapsulant film on the back of the solar cell 10. The backsheet provides protection and support for the solar cell 10, offering reliable insulation, water resistance, and aging resistance. Multiple backsheet options are available, typically including tempered glass, acrylic glass, and aluminum alloy TPT composite encapsulant film, with specific choices depending on the specific circumstances. The backsheet, solar cell 10, encapsulant film, and photovoltaic glass can be mounted on a metal frame. The metal frame serves as the main external support structure for the entire battery module, providing stable support and installation. For example, the battery module can be installed at the desired location using the metal frame.

[0078] The photovoltaic system of this disclosure includes the battery module described above.

[0079] In the photovoltaic system of this embodiment, since the apex angle of the second textured structure 132 located in the edge region 112 of the solar cell 10 of the battery module is larger than the apex angle of the first textured structure 131 located in the middle region 111, the passivation effect of the second textured structure 132 is better, and the anti-reflection effect of the first textured structure 131 is better, which is beneficial to improving the photoelectric conversion efficiency of the solar cell 10 as a whole.

[0080] In this embodiment, the photovoltaic system can be applied in photovoltaic power plants, such as ground-mounted power plants, rooftop power plants, and floating power plants. It can also be applied to equipment or devices that utilize solar energy to generate electricity, such as user solar power supplies, solar streetlights, solar cars, and solar buildings. Of course, it is understood that the application scenarios of the photovoltaic system are not limited to these; that is, the photovoltaic system can be applied in all fields that require solar energy to generate electricity. Taking a photovoltaic power generation system network as an example, the photovoltaic system may include a photovoltaic array, a combiner box, and an inverter. The photovoltaic array may be an array combination of multiple battery modules; for example, multiple battery modules can form multiple photovoltaic arrays. The photovoltaic array is connected to the combiner box, which can collect the current generated by the photovoltaic array. The collected current flows through the inverter and is converted into AC power required by the mains power grid before being connected to the mains power grid to achieve solar power supply.

[0081] In the description of this specification, the references to terms such as "some embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with an embodiment or example is included in at least one embodiment or example of this disclosure. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, the above are merely preferred embodiments of this disclosure and are not intended to limit this disclosure. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this disclosure should be included within the scope of protection of this disclosure.

Claims

1. A solar cell comprising two opposing surfaces and a plurality of side surfaces, the side surfaces being located between the two opposing surfaces; at least one of the surfaces having a central region and an edge region, the edge region surrounding the central region; the central region and the edge region respectively having a plurality of first textured structures and a plurality of second textured structures; The second velvet structure and the first velvet structure are conical in shape, and the apex angle of the second velvet structure is greater than the apex angle of the first velvet structure in a first preset ratio.

2. The solar cell according to claim 1, wherein, The first preset ratio is 50%-100%.

3. The solar cell according to claim 1, wherein, The difference between the maximum value of the apex angle of the second velvet structure and the maximum value of the apex angle of the first velvet structure is 0.5°-15°.

4. The solar cell according to claim 1, wherein, The apex angle of at least a portion of the second velvet structure is 75°-85° and the apex angle of at least a portion of the first velvet structure is 70°-82°, or the apex angle of at least a portion of the second velvet structure is 75°-85°, or the apex angle of at least a portion of the first velvet structure is 70°-82°.

5. The solar cell according to claim 1, wherein, The ratio of the width of the edge region to the width of the surface is 1:(5-100).

6. The solar cell according to claim 1, wherein, The edge region is ring-shaped and continuously surrounds the central region.

7. The solar cell according to claim 1, wherein, The size of the second velvet structure in the second preset ratio is smaller than the size of the first velvet structure.

8. The solar cell according to claim 7, wherein, The second preset ratio is 50%-100%.

9. The solar cell according to claim 7, wherein, The difference between the size of the second largest velvet structure and the size of the first largest velvet structure is 0.01 μm-3.7 μm.

10. A battery assembly comprising the solar cell according to any one of claims 1-9.

11. A photovoltaic system comprising the battery module of claim 10.

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