Solar cell and manufacturing method therefor, and photovoltaic module

Abstract

A solar cell and a manufacturing method therefor, and a photovoltaic module. The solar cell comprises a silicon substrate (100), wherein the silicon substrate (100) comprises a front surface and a back surface, the front surface and / or the back surface each comprise stress distribution regions (10), and the stress distribution regions (10) are at least distributed on two edges of either of the front surface and / or the back surface.

Description

Solar cells and their preparation methods, photovoltaic modules

[0001] Related applications

[0002] This application claims priority to Chinese patent application filed on January 22, 2025, application number 202510106401.3, entitled "Solar Cell and Method for Preparing the Same, Photovoltaic Module", the entire contents of which are incorporated herein by reference. Technical Field

[0003] This application relates to the field of solar cell technology, and in particular to a solar cell and its preparation method, and a photovoltaic module. Background Technology

[0004] Crystalline silicon (c-Si) solar cells are the dominant photovoltaic technology, accounting for approximately 95% of the market, and possess 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 fabricate flexible cells. Traditional thin-film solar cells, such as those made of amorphous silicon, cadmium telluride (CdTe), and perovskite, while flexible, have also failed to achieve large-scale production and application due to limitations such as low power conversion efficiency, the toxicity of some materials leading to environmental problems, and insufficient stability in large-area applications.

[0005] While reducing the thickness of silicon wafers can improve the mechanical flexibility of solar cells to some extent, thinner silicon wafers increase transmittance, reducing the amount of light absorbed by the cell and thus lowering the overall conversion efficiency. This makes it difficult to balance the flexibility of silicon wafers with photoelectric conversion efficiency. Summary of the Invention

[0006] According to various embodiments of this application, a solar cell and its preparation method, as well as a photovoltaic module, are provided; the solar cell not only has excellent flexibility, but also high photoelectric conversion efficiency, which is conducive to realizing the large-scale commercial production and application of flexible solar cells.

[0007] This application provides a solar cell including a silicon substrate, the silicon substrate including a front side and a back side, wherein the front side and / or the back side respectively include stress dispersion regions, and the stress dispersion regions are distributed on both sides of either the front side and / or the back side.

[0008] In one embodiment, with a baseline of 5.74% of the area of ​​the stress dispersion region in a silicon substrate with a thickness of 75 μm, the area of ​​the stress dispersion region increases by 2.5%-5.5% for every 5 μm decrease in the thickness of the silicon substrate.

[0009] In one embodiment, the width of the stress dispersion zone on any one side is less than or equal to 10.5 mm.

[0010] In one embodiment, the stress dispersion zone is symmetrically distributed on at least one of the front and back sides.

[0011] In one embodiment, when the silicon substrate is rectangular, at least one of the front and back sides has the stress dispersion region along its long side.

[0012] In one embodiment, when the silicon substrate is square, at least one of the front and back sides has the stress dispersion zone on all four sides.

[0013] In one embodiment, the front side further includes a first velvet area, and the back side further includes a second velvet area, the reflectivity of the second velvet area being less than that of the first velvet area.

[0014] In one embodiment, at a wavelength of 620 nm, the difference in reflectivity between the stress dispersion region and the second textured region is greater than or equal to 3%.

[0015] In one embodiment, the reflectivity of the stress dispersion zone is 13%-15%.

[0016] In one embodiment, the reflectivity of the first velvet area is 10%-12%.

[0017] In one embodiment, the reflectivity of the second velvet area is 9%-11%.

[0018] In one embodiment, the first velvet area includes a Y-shaped groove, and the second velvet area includes an X-shaped groove.

[0019] A method for fabricating a solar cell as described above includes the following steps: providing a silicon substrate; adding a mask to the silicon substrate to at least cover its edges; subjecting the silicon substrate with the added mask to visible light laser treatment under oxygen-rich conditions; forming the stress dispersion region after wet cleaning; or, selectively treating the silicon substrate with ultraviolet laser or green laser to obtain the stress dispersion region; or, selectively wet etching the silicon substrate to obtain the stress dispersion region; and fabricating a front structure and a back structure on the treated silicon substrate to obtain the solar cell.

[0020] A photovoltaic module, comprising a solar cell as described above.

[0021] Details of one or more embodiments of this application are set forth in the following drawings and description. Other features, objects, and advantages of this application will become apparent from the specification, drawings, and claims. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 is a schematic cross-sectional view of the silicon substrate of a solar cell according to one embodiment of this application.

[0024] Figure 2 is a schematic cross-sectional view of the silicon substrate of a solar cell according to another embodiment of this application.

[0025] Figure 3 is a schematic cross-sectional view of the silicon substrate of a solar cell according to another embodiment of this application.

[0026] Figure 4 is a schematic cross-sectional view of the silicon substrate of a solar cell according to another embodiment of this application.

[0027] Figure 5 is a scanning electron microscope image of the stress dispersion region in the silicon substrate prepared in Example 1.

[0028] Figure 6 is a schematic diagram of the flexible battery head and tail bending test.

[0029] Wherein, 100 is the silicon substrate; 10 is the stress dispersion region; 20 is the first textured region; 30 is the second textured region; and w is the width of the stress dispersion region. Detailed Implementation

[0030] This application includes the following advantages: To facilitate understanding, this application will be described in more detail below. However, it should be understood that this application can be implemented in many different forms and is not limited to the embodiments or examples described herein. Rather, these embodiments or examples are provided to provide a more thorough and complete understanding of the disclosure of this application.

[0031] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein in the specification of this application is for the purpose of describing particular implementations or embodiments only and is not intended to be limiting of this application. The optional range of the term "and / or" as used herein includes any one of two or more of the related listed items, as well as any and all combinations of the related listed items, including any two related listed items, any more related listed items, or a combination of all related listed items.

[0032] This application provides a solar cell including a silicon substrate 100, the silicon substrate 100 including a front side and a back side. As shown in Figures 1 and 2, the front side and / or the back side respectively include stress dispersion regions 10, and the stress dispersion regions 10 are distributed on both sides of either the front side and / or the back side.

[0033] It is understood that this application is applicable to various existing solar cell structures, including but not limited to heterojunction cells, and this application does not limit them. For example, for a heterojunction cell, the front side of the silicon substrate 100 includes a first intrinsic amorphous silicon layer, an N-type doped layer, a first transparent conductive thin 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 thin film layer, and a back electrode stacked from the inside to the outside. The front side and / or the back side each independently include a stress dispersion region 10, and the stress dispersion region 10 is distributed at least on both sides of either the front side and / or the back side.

[0034] When subjected to stress, traditional crystalline silicon (c-Si) wafers typically begin to crack at sharp points on the wafer surface, especially in textured areas such as channels between surface pyramids. When mechanical bending forces are applied, these sharp points generate concentrated stress, making them prone to cracking.

[0035] Based on this, the solar cell described in this application, by setting stress dispersion regions 10 at specific locations on the surface of the silicon substrate 100, forms smooth channels between pyramidal and other textured structures, effectively reducing the stress concentration caused by pyramidal and other textured structures in the solar cell. This helps to reduce the critical bending radius, reduce the number of cracks caused by bending of the silicon wafer, and give the solar cell excellent bending flexibility. At the same time, it reduces the impact of surface reflection on light collection efficiency, so that the flexibility and photoelectric conversion efficiency of the solar cell reach a delicate balance point, thereby giving the solar cell both excellent flexibility and photoelectric conversion efficiency.

[0036] It should be noted that the stress dispersion region 10 is only distributed in the edge region of the silicon substrate 100, and not on the entire surface of the silicon substrate 100. The difference between the stress dispersion region 10 and other areas of the silicon substrate 100 surface is that the stress dispersion region 10 is a non-textured structure, and can be optionally a polished surface; that is, the reflectivity of the stress dispersion region 10 is higher than the reflectivity of a pyramidal or other textured structure on the surface of the silicon substrate 100. When the direction of the applied mechanical bending force is towards the front, at least the front surface may have a stress dispersion region 10; when the direction of the applied mechanical bending force is towards the back surface, at least the back surface may have a stress dispersion region 10; when the applied mechanical bending force can be towards either the front or the back surface, both the front and back surfaces may have stress dispersion regions 10. The stress dispersion region 10 may be distributed on both symmetrical sides of either the front or the back surface, or on adjacent sides of either the front or the back surface; this application does not impose any restrictions on this.

[0037] In some embodiments, the stress dispersion zone 10 is distributed on at least two symmetrical sides of either the front and / or the back side, which is more conducive to improving the bending effect.

[0038] In any given face, a larger area proportion of the stress dispersion region 10 is more conducive to enhancing the overall mechanical flexibility of the solar cell, helping to reduce the risk of cracking or damage during handling and installation, thereby extending and improving the reliability of the photovoltaic module. However, a larger area proportion of the stress dispersion region 10 significantly reduces the light absorption effect, thus affecting the photoelectric conversion efficiency of the solar cell. Therefore, this application aims to ensure that the stress dispersion region 10 is sufficient to enhance mechanical performance while achieving optimal light reception and conversion efficiency of the solar cell.

[0039] In some embodiments, with a base of 5.74% of the area of ​​the stress dispersion region 10 in a silicon substrate 100 with a thickness of 75 μm, the area of ​​the stress dispersion region 10 increases by 2.5%-5.5% for every 5 μm reduction in the thickness of the silicon substrate 100. By reducing the thickness of the silicon substrate 100 to further improve flexibility, while synergistically controlling the area of ​​the stress dispersion region 10, the flexibility of the solar cell and the photoelectric conversion efficiency can be kept in balance.

[0040] It is understood that solar cells have different sizes based on different application requirements, that is, silicon substrates 100 of different sizes need to be used. Therefore, this application does not limit the specific size of the stress dispersion region 10.

[0041] Considering the dimensions of the conventional silicon substrate 100, in one embodiment, the width of the stress dispersion region 10 on any side is defined as w, and the width w of the stress dispersion region 10 on any side is less than or equal to 10.5 mm, and can be selected from 2 mm to 6 mm, including but not limited to any one of 2 mm, 3 mm, 4 mm, 5 mm, 6 mm or any range between two. It should be noted that the size of the stress dispersion region is related to the size of the silicon substrate 100. The size of the silicon substrate 100 has evolved from M0 to M12, and from 156mm to 156.75mm, 158.75mm, 161.70mm, 165mm, 166mm, 182mm, 185mm, 192mm, 200mm, and 210mm, and may continue to evolve to other sizes. The stress dispersion region can increase with the size of the silicon substrate 100, but it must not exceed 10% of the half-side length of the silicon substrate 100 after it has been cut in half. For example, for a 210mm silicon substrate 100, the width of the stress dispersion region on one side should generally not exceed 210mm × 10% × 50%. When the area of ​​the silicon substrate 100 decreases, the width of the stress dispersion region also decreases accordingly.

[0042] In one embodiment, the stress dispersion region 10 is symmetrically distributed on at least one of the front and back sides, that is: the stress dispersion region 10 is symmetrically distributed on the front side, or on the back side, or both the front and back sides are symmetrically distributed, which is beneficial for uniformly dispersing stress concentration and further improving the bending flexibility of the solar cell.

[0043] It should be noted that the silicon substrate 100 in the solar cell provided in this application can be of any shape, including but not limited to rectangular, square and other shapes, and this application does not limit it.

[0044] In one embodiment, when the silicon substrate 100 is rectangular, at least one of the long sides of the front and back sides may have stress dispersion areas 10, that is: on the front side of the rectangular silicon substrate 100, two long sides have stress dispersion areas 10, or on the back side of the rectangular silicon substrate 100, two long sides have stress dispersion areas 10, or on both the front and back sides of the rectangular silicon substrate 100, all four long sides have stress dispersion areas 10.

[0045] It is understood that the two short sides of the rectangular silicon substrate 100 may also have stress dispersion zones 10 on the front and back sides, and this application does not limit this.

[0046] In another embodiment, when the silicon substrate 100 is square, at least one of the four sides of the front and back sides may have stress dispersion areas 10, that is: stress dispersion areas 10 are present on the four sides of the front side of the square silicon substrate 100, or stress dispersion areas 10 are present on the four sides of the back side of the square silicon substrate 100, or stress dispersion areas 10 are present on all sides of the front and back sides of the square silicon substrate 100.

[0047] In one embodiment, the front side further includes a first textured area 20, and the back side further includes a second textured area 30. As shown in Figures 3 and 4, the reflectivity of the second textured area 30 is less than that of the first textured area 20. By setting different reflectivity between the front and back sides of the silicon substrate 100, the front side minimizes surface reflection, thereby maximizing light absorption. The higher reflectivity of the back side promotes internal reflection, effectively increasing the optical path length of incident light and allowing the light to stay in the silicon substrate 100 for a longer time. In particular, it can improve the EQE value in the long wavelength band, thereby minimizing light transmission loss and improving the overall conversion efficiency of the solar cell.

[0048] It is understood that the reflectivity of the first velvet area 20 and the second velvet area 30 can be achieved by adjusting the different velvet structure sizes of the front and back sides, as shown in Figure 3, or by adjusting the different velvet areas of the front and back sides, as shown in Figure 4. This application does not limit this.

[0049] In some embodiments, at a wavelength of 620 nm, the reflectance difference between the second textured region 30 and the first textured region 20 is greater than or equal to 0.5%. In some embodiments, the reflectance difference between the second textured region 30 and the first textured region 20 is 0.5%-1%, including but not limited to any one of 0.5%, 0.6%, 0.7%, 0.71%, 0.8%, 0.9%, 1%, or a range between any two.

[0050] In one embodiment, under a wavelength of 620nm, the reflectivity difference between the stress dispersion region 10 and the second textured region 30 is greater than or equal to 3%. By setting a certain reflectivity difference between the stress dispersion region 10 and the second textured region 30 in the silicon substrate 100, it can be ensured that more light source is absorbed, which is beneficial to further improve the photoelectric conversion efficiency of the solar cell.

[0051] In some embodiments, the reflectivity difference between the stress dispersion region 10 and the second velvet region 30 is 3%-5%, including but not limited to any one of 3%, 3.5%, 4%, 4.5%, 5%, or any range between the two.

[0052] In some embodiments, the reflectivity of the stress dispersion region 10 is 13%-15%, including but not limited to any one of 13%, 13.5%, 14%, 14.5%, 15%, or a range between any two.

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

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

[0055] In one embodiment, the first velvet area 20 may optionally include a Y-shaped groove, and the second velvet area 30 may optionally include an X-shaped groove.

[0056] It should be noted that the X-shaped groove structure refers to a textured 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 crisscrossing pattern on the silicon wafer surface. The intersecting grooves not only increase the optical path length inside the silicon wafer, enhancing light absorption through multiple internal reflections, but also help to distribute mechanical stress more evenly, improving the wafer's ability to handle bending and reducing the risk of microcracks.

[0057] In one embodiment, the surface of the first textured region 20 is further provided with a passivation layer, which helps to further reduce surface reflection, ensure that more light source is absorbed, and further improve the overall conversion efficiency of the solar cell.

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

[0059] This application provides a method for preparing a solar cell as described above, comprising the following steps.

[0060] Step S1: Provide a silicon substrate, add a mask to the silicon substrate to cover at least the edges, perform visible light laser treatment on the silicon substrate after adding the mask under oxygen-rich conditions, and form the stress dispersion region after wet cleaning; or, selectively treat the silicon substrate with ultraviolet laser or green laser to obtain the stress dispersion region; or, selectively wet etch the silicon substrate to obtain the stress dispersion region.

[0061] Step S2: Prepare the front and back structures of the processed silicon substrate to obtain the solar cell.

[0062] In step S1, during the visible light laser processing, a visible picosecond pulsed laser can be selected. Specifically, the laser pulse energy is 0.1 J / cm². 2 -1J / cm 2 The value can be set to 0.1 J / cm. 2 -0.4J / cm 2 The laser processing time is 1s-80s, selectable from 3s-20s; the laser power is 30W-60W.

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

[0064] In one embodiment, the laser pulse energy in selective laser processing is 0.1 J / cm². 2 -0.8J / cm 2 The value can be set to 0.2 J / cm. 2 -0.6J / cm 2 The laser processing time is 1s-120s, selectable from 1s-20s; the laser power is 20W-50W.

[0065] In step S2, it is understood that the processes for preparing the front and back structures are different for different solar cells. Existing publicly available processes can be used to prepare different solar cells, and this application does not limit this. For example, for heterojunction cells, an intrinsic amorphous silicon layer, a doped layer, a transparent conductive thin film layer, and an electrode can be deposited on the front and back sides respectively to prepare a heterojunction cell.

[0066] This application also provides a photovoltaic module, including the solar cell described above. The photovoltaic module can be widely used in various fields such as power generation, outdoor lighting, mobile power supplies, and aerospace, and this application does not limit its applications thereto.

[0067] The following specific embodiments will further illustrate the solar cell, its preparation method, and photovoltaic module. However, those skilled in the art will understand that the following embodiments are for illustrative purposes only and should not be considered as limiting the scope of this application. Unless otherwise specified, specific conditions in the embodiments are performed under conventional conditions or conditions recommended by the manufacturer. Reagents or instruments used without specified manufacturers are all commercially available conventional products.

[0068] Example 1

[0069] A 30W ultraviolet laser was used to grind the edges of a 210mm × 105mm silicon wafer for 2-4 seconds to obtain a silicon substrate. The scanning electron microscope (SEM) image of the stress dispersion zone in the silicon substrate is shown in Figure 5. It can be seen that the laser-polished edges have a more uniform distribution of mechanical stress, which helps reduce stress concentration and thus minimizes the risk of microcracks or fracture during bending cycles.

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

[0071] Example 2

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

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

[0074] Examples 3 to 6

[0075] Examples 3 to 6 used the same preparation method as Example 1, the difference being that different silicon substrates were obtained, as detailed in Table 1.

[0076] Table 1

[0077] Note: The reflectance values ​​in Table 1 were all tested at a wavelength of 620 nm.

[0078] The performance of the batteries prepared in all embodiments was tested, 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).

[0079] Table 2

[0080] As shown in Table 2, the solar cell provided in this application has an efficiency of approximately 25.1%-25.5%, an Isc of approximately 8.64A-8.67A, a Voc of approximately 0.754V-0.756V, and an FF of approximately 84.8-85.4. After a head-and-tail bending test as shown in Figure 6, the average efficiency only drops to approximately 0.25% after 1000 head-and-tail bending cycles, retaining more than 99% of the original conversion efficiency.

[0081] This application has the following advantages: The solar cell described in this application effectively reduces the stress concentration caused by the textured surface structure in the solar cell by setting stress dispersion regions at specific locations on the silicon substrate surface. This helps to reduce the critical bending radius, reduce the number of cracks caused by bending of the silicon wafer, and give the solar cell excellent bending flexibility. At the same time, it reduces the impact of surface reflection on light collection efficiency, thereby achieving a delicate balance between the flexibility and photoelectric conversion efficiency of the solar cell. As a result, the solar cell provided by this application 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.

[0082] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0083] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A solar cell comprising a silicon substrate, said silicon substrate including a front side and a back side, characterized in that, The front side and / or the back side each include a stress dispersion area, and the stress dispersion area is distributed on both sides of either the front side and / or the back side.

2. The solar cell according to claim 1, wherein, Based on a baseline of 5.74% for the area of ​​the stress dispersion region in a silicon substrate with a thickness of 75 μm, the area of ​​the stress dispersion region increases by 2.5%-5.5% for every 5 μm decrease in the thickness of the silicon substrate.

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

4. The solar cell according to claim 1, wherein, The stress dispersion zones are symmetrically distributed on at least one of the front and back sides.

5. The solar cell according to claim 1 or 4, wherein, When the silicon substrate is rectangular, at least one of the front and back sides has the stress dispersion area on its long side.

6. The solar cell according to claim 1 or 4, wherein, When the silicon substrate is square, at least one of the front and back sides has the stress dispersion zone on all four sides.

7. The solar cell according to claim 1, wherein, The front side also includes a first velvet area, and the back side also includes a second velvet area, wherein the reflectivity of the second velvet area is less than that of the first velvet area.

8. The solar cell according to claim 7, wherein, At a wavelength of 620 nm, the difference in reflectivity between the stress dispersion region and the second textured surface region is greater than or equal to 3%.

9. The solar cell according to claim 7 or 8, wherein, The reflectivity of the stress dispersion zone is 13%-15%.

10. The solar cell according to claim 7 or 8, wherein, The reflectivity of the first velvet surface area is 10%-12%.

11. The solar cell according to claim 7 or 8, wherein, The reflectivity of the second velvet surface area is 9%-11%.

12. The solar cell according to claim 7, wherein, The first velvet area includes a Y-shaped groove, and the second velvet area includes an X-shaped groove.

13. A method for preparing a solar cell according to any one of claims 1-12, characterized in that, Includes the following steps: A silicon substrate is provided, and a mask covering at least the edge is added to the silicon substrate. The silicon substrate with the added mask is subjected to visible light laser treatment under oxygen-rich conditions, and the stress dispersion region is formed after wet cleaning. Alternatively, the stress dispersion region is obtained by selectively treating the silicon substrate with ultraviolet laser or green laser, or by selectively wet etching the silicon substrate. The front and back structures are fabricated on the treated silicon substrate to obtain the solar cell.

14. A photovoltaic module, characterized in that, Including the solar cell as described in any one of claims 1-12.

Images