Solar cell, preparation method thereof and photovoltaic module

Abstract

The invention relates to a solar cell and a preparation method thereof, and a photovoltaic module, the solar cell comprises a silicon substrate, the silicon substrate comprises a front surface and a back surface, the front surface and / or the back surface respectively comprise a stress dispersion area, and the stress dispersion areas are at least distributed on two sides of any one of the front surface and / or the back surface. The solar cell has excellent flexibility and high photoelectric conversion efficiency, and large-scale commercial production and application of the flexible solar cell are facilitated.

Description

Technical Field

[0001] The present invention relates to the technical field of solar cells, and in particular to a solar cell and a preparation method thereof, and a photovoltaic module. Background Art

[0002] Crystalline silicon (c-Si) solar cells are the dominant photovoltaic technology accounting for about 95% of the market. They have technical advantages such as high power conversion efficiency, low manufacturing cost, and good stability. However, the inherent brittleness of silicon wafers makes them prone to cracking under bending stress, making it difficult to prepare silicon wafers into flexible cells. Traditional thin-film solar cells, such as amorphous silicon, cadmium telluride (CdTe), and perovskite, although flexible, have low power conversion efficiency, toxicity of some materials that cause environmental problems, and insufficient stability in large-area product applications. As a result, such flexible solar cells have not been able to achieve large-scale production and application.

[0003] Although reducing the thickness of silicon wafers can help improve the mechanical flexibility of solar cells to a certain extent, thin silicon wafers will increase the transmittance, reducing the amount of light absorbed by the cell, thereby reducing the overall conversion efficiency of the cell, making it difficult to balance the flexibility of silicon wafers and photoelectric conversion efficiency. Summary of the invention

[0004] Based on this, it is necessary to provide a solar cell and a preparation method thereof, and a photovoltaic module to address the above problems; the solar cell not only has excellent flexibility, but also has high photoelectric conversion efficiency, which is conducive to the large-scale commercial production and application of flexible solar cells.

[0005] A solar cell comprises a silicon substrate, wherein the silicon substrate comprises a front side and a back side, wherein the front side and / or the back side respectively comprise a stress dispersion zone, and the stress dispersion zone is distributed at least on both sides of any one of the front side and / or the back side.

[0006] In one embodiment, taking the area ratio of the stress dispersion zone in a silicon substrate with a thickness of 75 μm as 5.74% as a benchmark, the area ratio of the stress dispersion zone increases by 2.5%-5.5% for every 5 μm reduction in the thickness of the silicon substrate.

[0007] In one embodiment, the width of the stress dispersion zone on any side is less than or equal to 10.5 mm.

[0008] In one of the embodiments, the stress dispersion areas in at least one of the front side and the back side are symmetrically distributed.

[0009] In one embodiment, when the silicon substrate is rectangular, the long side of at least one of the front side and the back side has the stress dispersion area;

[0010] Alternatively, when the silicon substrate is in a square shape, four sides of at least one of the front surface and the back surface have the stress dispersion area.

[0011] In one embodiment, the front side further includes a first suede area, and the back side further includes a second suede area, and the reflectivity of the second suede area is less than the reflectivity of the first suede area.

[0012] In one of the embodiments, under the condition of a wavelength of 620 nm, the difference in reflectivity between the stress dispersion area and the second suede area is greater than or equal to 3%.

[0013] In one embodiment, the reflectivity of the stress dispersion area is 13%-15%;

[0014] And / or, the reflectivity of the first suede area is 10%-12%;

[0015] And / or, the reflectivity of the second suede area is 9%-11%.

[0016] In one embodiment, the first suede area includes a Y-shaped groove, and the second suede area includes an X-shaped groove.

[0017] A method for preparing the solar cell as described above comprises the following steps:

[0018] Providing a silicon substrate, adding a mask at least covering the edge of the silicon substrate, performing visible light laser treatment on the silicon substrate after adding the mask under oxygen-rich conditions, and forming the stress dispersion area after wet cleaning, or performing selective ultraviolet laser or green laser treatment on the silicon substrate to obtain the stress dispersion area, or performing selective wet etching on the silicon substrate to obtain the stress dispersion area;

[0019] The front structure and the back structure are prepared on the processed silicon substrate to obtain the solar cell.

[0020] A photovoltaic module comprises the solar cell described above.

[0021] The solar cell described in the present invention effectively reduces the stress concentration effect caused by the velvet structure in the solar cell by setting a stress dispersion zone with a specific position on the surface of the silicon substrate, which is beneficial to reducing the critical bending radius and the number of cracks caused by the bending of the silicon wafer, so that the solar cell has excellent bending flexibility. At the same time, it reduces the influence of surface reflection on the light collection efficiency, so that the flexibility and photoelectric conversion efficiency of the solar cell reach a delicate balance point, and the solar cell provided by the present invention has both excellent flexibility and photoelectric conversion efficiency, which also provides strong technical support for the large-scale commercial production and application of flexible solar cells. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0023] Figure 1 Schematic diagram of the cross-sectional structure of a silicon substrate of a solar cell in one embodiment of the present invention;

[0024] Figure 2 A schematic diagram of a cross-sectional structure of a silicon substrate of a solar cell in another embodiment of the present invention;

[0025] Figure 3 A schematic diagram of a cross-sectional structure of a silicon substrate of a solar cell in another embodiment of the present invention;

[0026] Figure 4 A schematic diagram of a cross-sectional structure of a silicon substrate of a solar cell in another embodiment of the present invention;

[0027] Figure 5 This is a scanning electron microscope image of the stress dispersion area in the silicon substrate obtained in Example 1;

[0028] Figure 6 Schematic diagram of the head-to-tail bending test of flexible batteries.

[0029] Among them, 10, stress dispersion area; 20, first velvet area; 30, second velvet area; w, width of the stress dispersion area. DETAILED DESCRIPTION

[0030] For ease of understanding of the present invention, the present invention will be described in more detail below. However, it should be understood that the present invention can be implemented in many different forms and is not limited to the embodiments or examples described herein. On the contrary, the purpose of providing these embodiments or examples is to make the understanding of the disclosure of the present invention more thorough and comprehensive.

[0031] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those generally understood by those skilled in the art of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific implementation methods or embodiments, and are not intended to limit the present invention. The optional scope of the term "and / or" used herein includes any one of two or more related listed items, and also includes any and all combinations of related listed items, and the combinations include any two related listed items, any more related listed items, or all related listed items.

[0032] The present invention provides a solar cell, comprising a silicon substrate, wherein the silicon substrate comprises a front surface and a back surface, Figure 1 and Figure 2 As shown, the front surface and / or the back surface respectively include stress dispersion areas 10, and the stress dispersion areas 10 are distributed at least on two sides of any one of the front surface and / or the back surface.

[0033] It can be understood that the present invention is applicable to various existing solar cell structures, including but not limited to heterojunction cells, etc., and the present invention is not limited to this. For example: for heterojunction cells, the front side of the silicon substrate includes a first intrinsic amorphous silicon layer, an N-type doped layer, a first transparent conductive film layer and a front electrode stacked from the inside to the outside, and the back side includes a second intrinsic amorphous silicon layer, a P-type doped layer, a second transparent conductive film layer and a back electrode stacked from the inside to the outside, wherein the front side and / or the back side independently include a stress dispersion zone 10, and the stress dispersion zone 10 is distributed on at least two sides of any one of the front side and / or the back side.

[0034] When traditional crystalline silicon (c-Si) wafers are subjected to stress, they usually begin to crack at sharp points on the surface of the wafer, especially in textured areas such as channels between surface pyramids. When mechanical bending force is applied, these sharp points will produce concentrated stress, causing them to crack easily.

[0035] Based on this, the solar cell described in the present invention, by setting a stress dispersion area 10 with a specific position on the surface of the silicon substrate, the stress dispersion area 10 forms a smooth channel between the velvet structures such as pyramids, effectively reducing the stress concentration effect caused by the velvet structures such as pyramids in the solar cell, which is beneficial to reducing the critical bending radius and reducing the number of cracks caused by bending of the silicon wafer, so that the solar cell has excellent bending flexibility. At the same time, it reduces the impact of surface reflection on the light collection efficiency, so that the flexibility of the solar cell and the photoelectric conversion efficiency reach a delicate balance point, so that the solar cell has both excellent flexibility and photoelectric conversion efficiency.

[0036] It should be noted that the stress dispersion zone 10 is only distributed in the edge area of ​​the silicon substrate, not distributed on the entire silicon substrate surface. The difference between the stress dispersion zone 10 and other areas on the surface of the silicon substrate is that the stress dispersion zone 10 is a non-velvet structure, preferably a polished surface, that is, the reflectivity of the stress dispersion zone 10 is higher than the reflectivity of the velvet structure such as the pyramid on the surface of the silicon substrate. When the direction of applying the mechanical bending force is toward the front side, it is preferred that at least the front side has a stress dispersion zone 10; when the direction of applying the mechanical bending force is toward the back side, it is preferred that at least the back side has a stress dispersion zone 10; when the mechanical bending force can be applied either toward the front side or toward the back side, it is preferred that both the front side and the back side have a stress dispersion zone 10. The stress dispersion zone 10 can be distributed on the symmetrical sides of any one of the front side and / or the back side, or can be distributed on the adjacent two sides of any one of the front side and / or the back side, and the present invention does not limit this.

[0037] Preferably, the stress dispersion area 10 is distributed at least on two symmetrical sides of any one of the front surface and / or the back surface, which is more conducive to improving the bending effect.

[0038] In any one surface, when the area ratio of the stress dispersion area 10 is larger, it is more conducive to enhancing the overall mechanical flexibility of the solar cell, which helps to reduce the risk of cracking or damage during the processing and installation of the solar cell, thereby extending and improving the reliability of the photovoltaic module. However, the larger the area ratio of the stress dispersion area 10 is, the more significantly the light absorption effect is reduced, thereby affecting the photoelectric conversion efficiency of the solar cell. Therefore, the present invention needs to ensure that the stress dispersion area 10 is sufficient to enhance the mechanical properties while enabling the solar cell to achieve the best light reception and conversion efficiency.

[0039] Preferably, taking the area ratio of the stress dispersion zone 10 in the silicon substrate with a thickness of 75 μm as 5.74% as a benchmark, the area ratio of the stress dispersion zone 10 increases by 2.5%-5.5% for every 5 μm reduction in the thickness of the silicon substrate. By reducing the thickness of the silicon substrate to further improve the flexibility while synergistically regulating the area ratio of the stress dispersion zone 10, the flexibility of the solar cell and the photoelectric conversion efficiency can be balanced.

[0040] It is understandable that, based on different application requirements, solar cells have different sizes, that is, silicon substrates of different sizes are required. Therefore, the present invention does not limit the specific size of the stress dispersion area 10 .

[0041] Considering the size of conventional silicon substrates, in one embodiment, the width w of the stress dispersion zone 10 on any side is less than or equal to 10.5 mm, preferably 2 mm-6 mm, including but not limited to any point value of 2 mm, 3 mm, 4 mm, 5 mm, 6 mm or any range value between the two. It should be noted that the size of the stress dispersion zone is related to the size of the silicon substrate. The size of the silicon substrate develops from M0- to M12, from 156 mm to 156.75 mm, 158.75 mm, 161.70 mm, 165 mm, 166 mm, 182 mm, 185 mm, 192 mm, 200 mm, 210 mm, and may develop other sizes. The stress dispersion zone can become larger as the size of the silicon substrate changes, but the stress dispersion zone at least does not exceed the half side length of the silicon substrate after being cut in half. For example, for a 210 mm silicon substrate, the width of the stress dispersion zone on one side should generally not exceed 210 mm × 10% × 50%. When the area of ​​the silicon substrate becomes smaller, the width of the stress dispersion zone also becomes smaller adaptively.

[0042] In one embodiment, the stress dispersion areas 10 are symmetrically distributed in at least one of the front and back surfaces, that is, the stress dispersion areas 10 are symmetrically distributed in the front surface, or the stress dispersion areas 10 are symmetrically distributed in the back surface, or the stress dispersion areas 10 are symmetrically distributed in both the front and back surfaces, which is beneficial to uniformly disperse the stress concentration effect and further improve the bending flexibility of the solar cell.

[0043] It should be noted that the silicon substrate in the solar cell provided by the present invention can be in any shape, including but not limited to rectangular, square and the like, and the present invention does not limit this.

[0044] In one embodiment, when the silicon substrate is rectangular, on the front and back sides, preferably at least one of the long sides has a stress dispersion area 10, that is, on the front side of the rectangular silicon substrate, the two long sides have stress dispersion areas 10, or, on the back side of the rectangular silicon substrate, the two long sides have stress dispersion areas 10, or, on the front and back sides of the rectangular silicon substrate, the four long sides on both sides have stress dispersion areas 10.

[0045] It is understandable that on the front and back sides of the rectangular silicon substrate, the two short sides may also have stress dispersion areas 10, and the present invention is not limited to this.

[0046] In another embodiment, when the silicon substrate is square, at least one of the front and back sides preferably has four sides with stress dispersion areas 10, that is, on the front side of the square silicon substrate, four sides have stress dispersion areas 10, or, on the back side of the square silicon substrate, four sides have stress dispersion areas 10, or, on both the front and back sides of the square silicon substrate, all sides have stress dispersion areas 10.

[0047] In one embodiment, the front side further comprises a first suede area 20, and the back side further comprises a second suede area 30. Figure 3 and Figure 4 As shown, the reflectivity of the second velvet area 30 is less than the reflectivity of the first velvet area 20. By setting the front and back sides of the silicon substrate to have different reflectivity levels, the front side can minimize surface reflection and maximize light absorption. The higher reflectivity of the back side can promote internal reflection, which can effectively increase the optical path length of the incident light and make the light stay longer in the silicon substrate. In particular, the EQE value in the long-wave band can be improved, thereby minimizing light transmission losses and further improving the overall conversion efficiency of the solar cell.

[0048] It is understandable that the reflectivity of the first suede area 20 and the second suede area 30 can be achieved by adjusting the different sizes of the suede structures on the front and back sides, such as Figure 3 As shown, it can also be achieved by adjusting the suede area on the front and back sides to be different, such as Figure 4 As shown, the present invention is not limited to this.

[0049] Preferably, under the condition of 620nm wavelength, the reflectivity difference between the second velvet area 30 and the first velvet area 20 is greater than or equal to 0.5%. Further preferably, the reflectivity difference between the second velvet area 30 and the first velvet area 20 is 0.5%-1%, including but not limited to any point value among 0.5%, 0.6%, 0.7%, 0.71%, 0.8%, 0.9%, 1% or any range value between two of them.

[0050] In one embodiment, under the condition of 620nm wavelength, the reflectivity difference between the stress dispersion zone 10 and the second velvet zone 30 is greater than or equal to 3%. By setting the stress dispersion zone 10 and the second velvet zone 30 in the silicon substrate to have a certain reflectivity difference, more light sources can be absorbed, which is beneficial to further improve the photoelectric conversion efficiency of the solar cell.

[0051] Preferably, the reflectivity difference between the stress dispersion area 10 and the second suede area 30 is 3%-5%, including but not limited to any point value among 3%, 3.5%, 4%, 4.5%, 5% or any range value between two of them.

[0052] More preferably, the reflectivity of the stress dispersion area 10 is 13%-15%, including but not limited to any point value among 13%, 13.5%, 14%, 14.5%, 15% or any range value between two of them.

[0053] The reflectivity of the first suede area 20 is 10%-12%, including but not limited to any value among 10%, 10.5%, 11%, 11.5%, 12% or any range between two values.

[0054] The reflectivity of the second suede area 30 is 9%-11%, including but not limited to any value among 9%, 9.5%, 10%, 10.5%, 11% or any range between two values.

[0055] In one embodiment, the first suede area 20 preferably includes a Y-shaped groove, and the second suede area 30 preferably includes an X-shaped groove.

[0056] It should be noted that the X-shaped groove structure refers to a texture pattern composed of intersecting grooves that form an "X" shape when viewed from the surface. This structure is characterized by the grooves intersecting at a certain angle, forming a criss-cross pattern on the surface of the silicon wafer; the intersecting grooves not only increase the optical path length inside the silicon wafer, which is beneficial for enhancing light absorption through multiple internal reflections, but also help to distribute mechanical stress more evenly, improve the ability of the wafer to handle bending, and reduce the risk of microcracks.

[0057] In one embodiment, a passivation layer is further provided on the surface of the first suede area 20, which is beneficial to further reduce surface reflection, ensure that more light sources are absorbed, and further improve the overall conversion efficiency of the solar cell.

[0058] Specifically, the passivation layer on the surface of the first textured area 20 includes but is not limited to silicon nitride.

[0059] The present invention provides a method for preparing the solar cell as described above, comprising the following steps:

[0060] S1, providing a silicon substrate, adding a mask at least covering the edge of the silicon substrate, performing visible light laser treatment on the silicon substrate after adding the mask under oxygen-rich conditions, and forming the stress dispersion area after wet cleaning, or performing selective ultraviolet laser or green laser treatment on the silicon substrate to obtain the stress dispersion area, or performing selective wet etching on the silicon substrate to obtain the stress dispersion area;

[0061] S2, preparing a front structure and a back structure for the treated silicon substrate to obtain the solar cell.

[0062] In step S1, in the visible light laser treatment step, it is preferred to use a visible picosecond pulse laser. Specifically, the laser pulse energy is 0.1 J / cm 2 -1J / cm 2 , preferably 0.1 J / cm 2 -0.4J / cm 2; The laser treatment time is 1s-80s, preferably 3s-20s; the laser power is 30W-60W.

[0063] In one embodiment, wet cleaning includes acid cleaning or alkaline cleaning, wherein the acid cleaning solution includes but is not limited to a mixture of 90%-91% hydrofluoric acid and 9%-10% water, or a mixture of 67%-69% nitric acid and 31%-33% water, and the alkaline cleaning solution includes but is not limited to a mixture of 67%-69% potassium hydroxide and 31%-33% water.

[0064] In one embodiment, in the selective laser processing, the laser pulse energy is 0.1 J / cm 2 -0.8J / cm 2 , preferably 0.2 J / cm 2 -0.6J / cm 2 ; The laser treatment time is 1s-120s, preferably 1s-20s; the laser power is 20W-50W.

[0065] In step S2, it can be understood that for different solar cells, the processes for preparing the front structure and the back structure are different. Different solar cells can be prepared using existing disclosed processes, and the present invention does not limit this. For example, for a heterojunction cell, an intrinsic amorphous silicon layer, a doping layer, a transparent conductive film layer and an electrode are deposited on the front and back sides respectively to obtain a heterojunction cell.

[0066] The present invention also provides a photovoltaic module, comprising the solar cell described above. The photovoltaic module can be widely used in multiple fields such as power generation, outdoor lighting, mobile power supply, and aerospace, and the present invention does not limit this.

[0067] The solar cell and its preparation method and photovoltaic module will be further described below by the following specific examples. However, those skilled in the art will understand that the following examples are only used to illustrate the present invention and should not be considered to limit the scope of the present invention. If no specific conditions are specified in the examples, the conventional conditions or the conditions recommended by the manufacturer are followed. If the manufacturer of the reagents or instruments used is not specified, they are all conventional products that can be purchased commercially.

[0068] Example 1

[0069] Using a UV laser with a total power of 30W, the edge of a 210mm×105mm silicon wafer was ground for 2-4 seconds to produce a silicon substrate. The SEM image of the stress dispersion area in the silicon substrate is shown in Figure 5 As shown, it can be seen that the laser polished edge distributes mechanical stress more evenly, which helps to reduce stress concentration and thus minimize the risk of micro cracks or fractures during bending cycles.

[0070] The silicon substrate was transferred to a PECVD vacuum chamber and the i, n and p layers were deposited. The i layer with a thickness of about 5 nm was deposited on both sides of the silicon substrate. A phosphorus-doped nanocrystal layer with a thickness of about 16 nm and a boron-doped nanocrystal layer with a thickness of about 22 nm were deposited on both sides of the i layer as the electron transport layer and the hole transport layer, respectively. Using an indium tin oxide (ITO) target, a TCO layer with a thickness of about 70 nm was deposited on both sides by a PVD device. Conventional silver screen printing was performed using a grid line with a line width of about 24 μm, followed by thermal annealing for 30 minutes and light injection for 90 seconds at 210°C to produce a heterojunction cell.

[0071] Example 2

[0072] A green laser with a total power of 60W was used to grind the edge of a 210mm×105mm silicon wafer for 2-4 seconds to obtain a silicon substrate.

[0073] The silicon substrate was transferred to a PECVD vacuum chamber and the i, n and p layers were deposited. The i layer with a thickness of about 8 nm was deposited on both sides of the silicon substrate. A phosphorus-doped nanocrystal layer with a thickness of about 18 nm and a boron-doped nanocrystal layer with a thickness of about 26 nm were deposited on both sides of the i layer as the electron transport layer and the hole transport layer, respectively. Using an indium tin oxide (ITO) target, a TCO layer with a thickness of about 65 nm was deposited on both sides by a PVD device. Conventional silver screen printing was performed using a grid line with a line width of about 18 μm, followed by thermal annealing for 30 minutes and light injection for 90 seconds at 210°C to produce a heterojunction cell.

[0074] Example 3 to Example 6

[0075] Examples 3 to 6 adopt the same preparation method as Example 1, except that the prepared silicon substrates are different, refer to Table 1 for details.

[0076] Table 1

[0077]

[0078] Note: The reflectivity in Table 1 was tested at a wavelength of 620nm.

[0079] The performance tests of the batteries prepared in all embodiments were carried out respectively, and the results are shown in Table 2. The specific performance parameters include: short-circuit current (Isc), open-circuit voltage (Voc), conversion efficiency (Eff), fill factor (FF), maximum power (Pmax), series resistance (Rs), parallel resistance (Rsh), reverse current (Irev2), average efficiency (Av.Eff), and maximum efficiency (MaxEff).

[0080] Table 2

[0081]

[0082] According to Table 2, the efficiency of the solar cell provided by the present invention is about 25.1%-25.5%, Isc is about 8.64-8.67, Voc is about 0.754V-0.756V, FF is about 84.8-85.4, and the Figure 6 The head-to-tail bending test shown shows that after 1000 head-to-tail bending cycles, the average efficiency only drops to about 0.25%, retaining more than 99% of the original conversion efficiency.

[0083] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0084] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A solar cell comprising a silicon substrate, wherein the silicon substrate comprises a front surface and a back surface, wherein: The front surface and / or the back surface respectively include stress dispersion areas, and the stress dispersion areas are distributed at least on two sides of any one of the front surface and / or the back surface.

2. The solar cell according to claim 1, characterized in that Taking the area ratio of the stress dispersion zone in a silicon substrate with a thickness of 75 μm as 5.74% as a benchmark, the area ratio of the stress dispersion zone increases by 2.5%-5.5% for every 5 μm reduction in the thickness of the silicon substrate.

3. The solar cell according to claim 1 or 2, characterized in that: The width of the stress dispersion zone on any side is less than or equal to 10.5 mm.

4. The solar cell according to claim 1, characterized in that The stress dispersion areas in at least one of the front side and the back side are symmetrically distributed.

5. The solar cell according to claim 1 or 4, characterized in that: When the silicon substrate is rectangular, the long side of at least one of the front side and the back side has the stress dispersion area; Alternatively, when the silicon substrate is in a square shape, four sides of at least one of the front surface and the back surface have the stress dispersion area.

6. The solar cell according to claim 1, characterized in that The front side further includes a first suede area, and the back side further includes a second suede area, wherein the reflectivity of the second suede area is lower than the reflectivity of the first suede area.

7. The solar cell according to claim 6, characterized in that: Under the condition of a wavelength of 620 nm, the difference in reflectivity between the stress dispersion area and the second suede area is greater than or equal to 3%.

8. The solar cell according to claim 6 or 7, characterized in that: The reflectivity of the stress dispersion zone is 13%-15%; And / or, the reflectivity of the first suede area is 10%-12%; And / or, the reflectivity of the second suede area is 9%-11%.

9. The solar cell according to claim 6, characterized in that: The first suede area includes a Y-shaped groove, and the second suede area includes an X-shaped groove.

10. A method for preparing a solar cell according to any one of claims 1 to 9, characterized in that: The steps include: Providing a silicon substrate, adding a mask at least covering the edge of the silicon substrate, performing visible light laser treatment on the silicon substrate after adding the mask under oxygen-rich conditions, and forming the stress dispersion area after wet cleaning, or performing selective ultraviolet laser or green laser treatment on the silicon substrate to obtain the stress dispersion area, or performing selective wet etching on the silicon substrate to obtain the stress dispersion area; The front structure and the back structure are prepared on the processed silicon substrate to obtain the solar cell.

11. A photovoltaic module, characterized in that: The invention comprises a solar cell as claimed in any one of claims 1 to 9.

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