Solar cell
By setting stress dispersion zones on the surface of the silicon substrate, the problem of easy cracking of crystalline silicon solar cells under bending stress was solved, achieving a balance between flexibility and high-efficiency photoelectric conversion, and promoting the commercialization of flexible solar cells.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- RISEN ENERGY CO LTD
- Filing Date
- 2025-01-22
- Publication Date
- 2026-05-19
AI Technical Summary
Existing crystalline silicon solar cells are prone to cracking under bending stress, and it is difficult to balance flexibility and photoelectric conversion efficiency. Traditional flexible solar cells have problems such as low power conversion efficiency, material toxicity and insufficient stability, which limit their large-scale application.
Stress dispersion zones are set on the front and/or back of the silicon substrate. By forming smooth channels between the textured structures, stress concentration is reduced, flexibility is enhanced, and reflectivity differences are optimized to improve photoelectric conversion efficiency.
This achieves a balance between the excellent bending flexibility and high photoelectric conversion efficiency of flexible solar cells, supporting their large-scale commercial production and application.
Smart Images
Figure CN224265409U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of battery technology, and in particular to a solar cell. Background Technology
[0002] 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.
[0003] 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. Utility Model Content
[0004] Therefore, it is necessary to provide a solar cell to address the above problems; 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.
[0005] A solar cell includes a silicon substrate, the silicon substrate having a front side and a back side, wherein the front side and / or the back side each include a stress dispersion region, the stress dispersion region being distributed at least on both sides of either the front side and / or the back side.
[0006] 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.
[0007] In one embodiment, the width of the stress dispersion zone on any one side is less than or equal to 10.5 mm.
[0008] In one embodiment, the stress dispersion zone is symmetrically distributed on at least one of the front and back sides.
[0009] 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.
[0010] 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.
[0011] 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.
[0012] 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%.
[0013] In one embodiment, the reflectivity of the stress dispersion zone is 13%-15%;
[0014] And / or, the reflectivity of the first velvet area is 10%-12%;
[0015] And / or, the reflectivity of the second velvet area is 9%-11%.
[0016] In one embodiment, the first velvet area includes a Y-shaped groove, and the second velvet area includes an X-shaped groove.
[0017] The solar cell described in this invention effectively reduces the stress concentration caused by the textured surface structure of the solar cell by setting stress dispersion zones at specific locations on the silicon substrate surface. This helps to reduce the critical bending radius, decrease the number of cracks caused by silicon wafer bending, 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 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. Attached Figure Description
[0018] To more clearly illustrate the technical solutions of this utility model, the drawings used in this utility model will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0019] Figure 1 This is a schematic diagram of the cross-sectional structure of the silicon substrate of the solar cell in one embodiment of the present invention;
[0020] Figure 2 This is a schematic diagram of the cross-sectional structure of the silicon substrate of the solar cell in another embodiment of the present invention;
[0021] Figure 3 This is a schematic diagram of the cross-sectional structure of the silicon substrate of the solar cell in another embodiment of the present invention;
[0022] Figure 4 This is a schematic diagram of the cross-sectional structure of the silicon substrate of the solar cell in another embodiment of the present invention.
[0023] Wherein, 10 is the stress dispersion zone; 20 is the first napped area; 30 is the second napped area; and w is the width of the stress dispersion zone. Detailed Implementation
[0024] To facilitate understanding of this utility model, it will be described in more detail below. However, it should be understood that this utility model 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 make the disclosure of this utility model more thorough and complete.
[0025] 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 invention pertains. The terminology used herein is for the purpose of describing particular embodiments or examples only and is not intended to be limiting of the invention.
[0026] This utility model provides a solar cell, including a silicon substrate, wherein the silicon substrate includes a front side and a back side, and is combined with... Figure 1 and Figure 2 As shown, the front side and / or the back side each include a stress dispersion region 10, and the stress dispersion region 10 is distributed on both sides of either the front side and / or the back side.
[0027] It is understood that this utility model is applicable to various existing solar cell structures, including but not limited to heterojunction cells, and this utility model does not limit them. For example, for a heterojunction cell, the front side of the silicon substrate 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.
[0028] 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.
[0029] Based on this, the solar cell of this utility model, by setting stress dispersion regions 10 at specific locations on the surface of the silicon substrate, 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, thus giving the solar cell both excellent flexibility and photoelectric conversion efficiency.
[0030] It should be noted that the stress dispersion region 10 is only distributed in the edge area of the silicon substrate, and not on the entire surface of the silicon substrate. The difference between the stress dispersion region 10 and other areas on the silicon substrate surface is that the stress dispersion region 10 is a non-textured structure, preferably a polished surface, meaning that the reflectivity of the stress dispersion region 10 is higher than the reflectivity of textured structures such as pyramids on the silicon substrate surface. When the direction of the applied mechanical bending force is towards the front, it is preferable that at least the front has a stress dispersion region 10; when the direction of the applied mechanical bending force is towards the back, it is preferable that at least the back has a stress dispersion region 10; when the applied mechanical bending force can be towards either the front or the back, it is preferable that both the front and the back have stress dispersion regions 10. The stress dispersion region 10 can be distributed on both symmetrical sides of either the front or the back, or on adjacent sides of either the front or the back; this invention does not impose any limitations on this.
[0031] Preferably, 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.
[0032] In any given surface, 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 invention aims to ensure that the stress dispersion region 10 is sufficient to enhance mechanical performance while enabling the solar cell to achieve optimal light reception and conversion efficiency.
[0033] Preferably, with a base of 5.74% of the area of the stress dispersion region 10 in a silicon substrate 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. By reducing the thickness of the silicon substrate 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.
[0034] It is understood that solar cells have different sizes based on different application requirements, that is, different sizes of silicon substrates are required. Therefore, this invention does not limit the specific size of the stress dispersion region 10.
[0035] Considering the dimensions of a conventional silicon substrate, in one embodiment, the width w of the stress dispersion region 10 on any one side is less than or equal to 10.5 mm, preferably 2 mm to 6 mm, including but not limited to any value among 2 mm, 3 mm, 4 mm, 5 mm, and 6 mm, or any range between two values. It should be noted that the size of the stress dispersion region is related to the size of the silicon substrate. Silicon substrate sizes have evolved 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, and 210 mm, and other sizes may also be developed. The stress dispersion region can increase with the size of the silicon substrate, but the stress dispersion region should not exceed the length of half the silicon substrate after it has been cut in half. For example, for a 210 mm silicon substrate, the width of the stress dispersion region on one side should generally not exceed 210 mm × 10% × 50%. As the area of the silicon substrate decreases, the width of the stress dispersion zone also decreases accordingly.
[0036] 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.
[0037] It should be noted that the silicon substrate in the solar cell provided by this utility model can be of any shape, including but not limited to irregular shapes such as rectangles, squares, and pentagons, and this utility model does not limit it in this respect.
[0038] In one embodiment, when the silicon substrate is rectangular, preferably at least one of the long sides of the front and back sides has stress dispersion areas 10, that is: on the front side of the rectangular silicon substrate, two long sides have stress dispersion areas 10, or on the back side of the rectangular silicon substrate, two long sides have stress dispersion areas 10, or on both the front and back sides of the rectangular silicon substrate, all four long sides have stress dispersion areas 10.
[0039] It is understood that the two short sides of the rectangular silicon substrate can also have stress dispersion zones 10 on the front and back sides, and this invention does not limit this.
[0040] In another embodiment, when the silicon substrate is square, preferably at least one of the four sides of the front and back sides has stress dispersion areas 10, that is: on the front side of the square silicon substrate, the four sides have stress dispersion areas 10, or on the back side of the square silicon substrate, the 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.
[0041] In one embodiment, the front side further includes a first napped area 20, and the back side further includes a second napped area 30, combined with Figure 3 and Figure 4 As shown, the reflectivity of the second textured region 30 is less than that of the first textured region 20. By setting different reflectivity between the front and back sides of the silicon substrate, the front side minimizes surface reflection, thereby maximizing light absorption. The higher reflectivity of the back side promotes internal reflection, which can effectively increase the optical path length of incident light and allow the light to stay in the silicon substrate 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.
[0042] 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 suede structure sizes on the front and back sides, such as... Figure 3 As shown, this can also be achieved by adjusting the different areas of the nap on the front and back sides, such as... Figure 4 As shown, this utility model does not impose any limitations on this.
[0043] Preferably, under a wavelength of 620nm, the reflectance difference between the second textured region 30 and the first textured region 20 is greater than or equal to 0.5%. More preferably, 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 any range between the two.
[0044] 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, it can be ensured that more light source is absorbed, which is beneficial to further improve the photoelectric conversion efficiency of the solar cell.
[0045] Preferably, 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.
[0046] More preferably, the reflectivity of the stress dispersion zone 10 is 13%-15%, including but not limited to any one of 13%, 13.5%, 14%, 14.5%, 15% or any range between two.
[0047] 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.
[0048] 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.
[0049] In one embodiment, the first velvet area 20 preferably includes a Y-shaped groove, and the second velvet area 30 preferably includes an X-shaped groove.
[0050] 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.
[0051] 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.
[0052] Specifically, the passivation layer on the surface of the first textured region 20 includes, but is not limited to, silicon nitride.
[0053] 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.
[0054] The embodiments described above are merely illustrative of several implementations of this utility model, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the utility model patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this utility model, and these all fall within the protection scope of this utility model. Therefore, the protection scope of this utility model patent 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 at least on both sides of either the front side and / or the back side; 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.
2. The solar cell according to claim 1, characterized in that, The width of the stress dispersion zone on any one side is less than or equal to 10.5 mm.
3. The solar cell according to claim 1, characterized in that, The stress dispersion zones are symmetrically distributed on at least one of the front and back sides.
4. The solar cell according to claim 1 or 3, characterized in that, When the silicon substrate is rectangular, at least one of the front and back sides has the stress dispersion area on its long side.
5. The solar cell according to claim 1 or 3, characterized in that, When the silicon substrate is square, at least one of the front and back sides has the stress dispersion zone on all four sides.
6. The solar cell according to claim 1, characterized in that, 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.
7. The solar cell according to claim 6, characterized in that, Under a wavelength of 620nm, the difference in reflectivity between the stress dispersion region and the second textured surface region is greater than or equal to 3%.
8. The solar cell according to any one of claims 6 or 7, characterized in that, The reflectivity of the stress dispersion zone is 13%-15%; And / or, the reflectivity of the first velvet surface area is 10%-12%; And / or, the reflectivity of the second velvet area is 9%-11%.
9. The solar cell according to claim 6, characterized in that, The first velvet area includes a Y-shaped groove, and the second velvet area includes an X-shaped groove.