Solar cell, photovoltaic module and photovoltaic system

Abstract

The invention is suitable for the technical field of solar cells, and provides a solar cell, a photovoltaic module and a photovoltaic system, the solar cell comprises a silicon substrate, a first passivation film and a second passivation film, the silicon substrate comprises a first surface, a second surface and a plurality of cutting surfaces, the first surface and the second surface are opposite, and the cutting surfaces are connected with the first surface and the second surface; the cutting surface comprises a first area close to the first surface and a second area close to the second surface; the first passivation film is arranged in the first area, and the second passivation film is arranged in the second area; the charge characteristics of the first passivation film are different from those of the second passivation film; the charge characteristic is a charge type or charge density. Therefore, the passivation effect of the solar cell can be optimized.

Description

Technical Field

[0001] This application belongs to the field of solar cell technology, and particularly relates to a solar cell, photovoltaic module and photovoltaic system. Background Technology

[0002] During the process of cutting a whole battery cell into several battery segments, a cutting surface is formed, and the passivation effect of the cutting surface is poor. Summary of the Invention

[0003] This application provides a solar cell, a photovoltaic module, and a photovoltaic system, which aim to optimize the passivation effect of the solar cell.

[0004] To achieve the above objectives, the present invention provides the following technical solution: In a first aspect, a solar cell is provided, comprising: a silicon substrate, a first passivation film, and a second passivation film. The silicon substrate includes a first surface and a second surface opposite to each other, and a plurality of cut surfaces connecting the first surface and the second surface. The cut surfaces include a first region near the first surface and a second region near the second surface. The first passivation film is disposed in the first region, and the second passivation film is disposed in the second region. The charge characteristics of the first passivation film are different from the charge characteristics of the second passivation film. The charge characteristics are charge type or charge density.

[0005] In some embodiments, the charge type of the first passivation film is positive or negative; the charge type of the second passivation film is negative; when the charge type of the first passivation film is negative; the charge density of the first passivation film is less than the charge density of the second passivation film.

[0006] In some embodiments, the second passivation film comprises an alumina film or a Lewis acid material film.

[0007] In some embodiments, the thickness of the alumina film in the lateral direction is 10 nm to 200 nm; the lateral direction is the direction from the silicon substrate to the cut surface.

[0008] In some embodiments, the thickness of the Lewis acidic material film in the lateral direction is 500 nm to 5000 nm; the lateral direction is the direction from the silicon substrate to the cut surface.

[0009] In some embodiments, the charge type of the first passivation film is positive; the first passivation film includes one or more of silicon nitride film, silicon oxynitride film and silicon oxide film.

[0010] In some embodiments, the first passivation film includes an aluminum oxide film and a silicon nitride film; the silicon nitride film is located on the side of the aluminum oxide film facing away from the silicon substrate.

[0011] In some embodiments, the thickness of the alumina film in the lateral direction is 1.8 nm to 9 nm; the lateral direction is the direction from the silicon substrate to the cut surface.

[0012] In some embodiments, the thickness of the silicon nitride film in the lateral direction is 75 nm to 155 nm; the lateral direction is the direction from the silicon substrate to the cut surface.

[0013] In some embodiments, the charge type of the first passivation film is negative; the first passivation film includes one or more of silicon nitride film, silicon oxynitride film and silicon oxide film, and aluminum oxide film.

[0014] In some embodiments, the size ratio of the first passivation film and the second passivation film in the thickness direction of the silicon substrate is 1:5 to 1:30.

[0015] In some embodiments, the dimensions of the first passivation film in the thickness direction of the silicon substrate are 5 μm to 40 μm.

[0016] In some embodiments, the dimensions of the second passivation film in the thickness direction of the silicon substrate are 60 μm to 155 μm.

[0017] In some embodiments, the solar cell further includes a P-type doped layer and an N-type doped layer, wherein the P-type doped layer is disposed on the first side and the N-type doped layer is disposed on the second side.

[0018] In some embodiments, the solar cell further includes a P-type doped layer and an N-type doped layer, which are alternately arranged on the second surface.

[0019] In some embodiments, the cutting surface further includes a third region located between the first region and the second region; the third region is used to isolate the first region and the second region.

[0020] In a second aspect, the present invention provides a photovoltaic module, which includes any of the possible solar cells described above.

[0021] Thirdly, the present invention provides a photovoltaic system, which includes the photovoltaic modules described above.

[0022] The beneficial effects of this invention are as follows: The solar cells, photovoltaic modules, and photovoltaic systems of this application embodiment are provided with a first passivation film and a second passivation film with different charge characteristics on the cut surface. The charge characteristics are charge type or charge density. In this way, different charge types or different charge densities can avoid the formation of inversion cancellation at the passivation film connection interface, forming a high recombination center and optimizing the passivation effect of the solar cell. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the structure of a solar cell provided in an embodiment of this application; Figure 2This is a schematic diagram of the structure of a solar cell provided in another embodiment of this application.

[0024] Explanation of key component symbols: Solar cell 10; Silicon substrate 11; First passivation film 12; Second passivation film 13; First surface 111, Second surface 112, Cut surface 113. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of this application 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 application, and should not be construed as limiting this application. Furthermore, it should be understood that the specific embodiments described herein are merely for explaining this application and are not intended to limit this application.

[0026] In the description of this application, 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 application and simplifying the description, and do not 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 application.

[0027] 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. Therefore, features defined as "first" or "second" may explicitly or implicitly include one or more features. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0028] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" 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 application according to the specific circumstances.

[0029] In this application, 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 being 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 being 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.

[0030] The following disclosure provides numerous different embodiments or examples for implementing various structures of this application. 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 application. 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 application, but those skilled in the art will recognize the application of other processes and / or the use of other materials.

[0031] During the process of cutting a whole battery cell into several battery segments, a cutting surface is formed, and the passivation effect of the cutting surface is poor.

[0032] In this regard, according to one aspect of this application, a solar cell is provided, such as Figure 1 ,as well as Figure 2 As shown, it includes: a silicon substrate 11, a first passivation film 12, and a second passivation film 13. The silicon substrate 11 includes a first surface 111 and a second surface 112 opposite to each other, and a plurality of cut surfaces 113 connecting the first surface 111 and the second surface 112. The cut surface 113 includes a first region near the first surface 111 and a second region near the second surface 112; The first passivation film 12 is disposed in the first region, and the second passivation film 13 is disposed in the second region; The charge characteristics of the first passivation film 12 are different from those of the second passivation film 13; the charge characteristics are charge type or charge density.

[0033] The solar cell 10, photovoltaic module, and photovoltaic system of this application embodiment are provided with a first passivation film 12 and a second passivation film 13 with different charge characteristics on the cut surface 113. The charge characteristics are charge type or charge density. In this way, different charge types or different charge densities can avoid the formation of inversion cancellation at the passivation film connection interface, forming a high recombination center and optimizing the passivation effect of the solar cell 10.

[0034] In one embodiment of the present invention, the first surface 111 is a backlight surface, and its second surface is disposed on the other side of the silicon substrate 11 relative to the first surface; that is, the first surface and the second surface are located on different sides of the silicon substrate 11 and are opposite sides. In this embodiment, the silicon substrate 11 is an N-type monocrystalline silicon wafer. It is understood that in other embodiments, the silicon substrate 11 may also be other types of silicon wafers such as polycrystalline silicon wafers or quasi-monocrystalline silicon wafers. The silicon substrate 11 is configured according to the actual use needs, and no specific limitation is made here.

[0035] It should be noted that the number of cut surfaces 113 can be determined according to the cutting method of the entire battery cell.

[0036] For example, if the solar cell 10 is cut into two pieces from a whole cell, the cutting surface 113 of the solar cell 10 can be one; if the solar cell 10 is cut into three or more pieces from a whole cell, the cutting surface 113 of the solar cell 10 can be one or two.

[0037] Specifically, the first passivation film 12 is disposed on the entire surface of the first region, and the second passivation film 13 is disposed on the entire surface of the second region.

[0038] In some embodiments, the first region and the second region are adjacent.

[0039] In some embodiments, the cut surface 113 further includes a third region located between the first and second regions; the third region serves to isolate the first and second regions. The third region is not covered with a passivation film. In still some embodiments, the third region is covered with an insulating film, which includes at least one of silicon oxide, titanium oxide, zirconium oxide, hafnium oxide, EVA (ethylene-vinyl acetate copolymer), and PET (polyethylene glycol terephthalate). This provides both insulation and buffering, which is beneficial for battery protection.

[0040] Specifically, charge types include negative and positive charges, and charge density refers to the amount of charge per unit area.

[0041] In some embodiments, the charge type of the first passivation film 12 is positive or negative; the charge type of the second passivation film 13 is negative; when the charge type of the first passivation film 12 is negative, the charge density of the first passivation film 12 is less than the charge density of the second passivation film 13.

[0042] That is, in the first case, the charge type of the first passivation film 12 is positive; the charge type of the second passivation film 13 is negative.

[0043] Thus, the first passivation film 12 has a positive charge type, which can form a strong positive charge type field passivation, avoid the formation of anti-recombination at the connection interface, form a high recombination center, and improve the passivation effect of the battery.

[0044] That is, in the second case, the charge type of the first passivation film 12 and the second passivation film 13 is negative; the charge density of the first passivation film 12 is less than the charge density of the second passivation film 13.

[0045] For example, the charge density of the first passivation film 12 is less than 3E12 / cm. 2 The charge density of the second passivation film 13 is greater than 3E12 / cm. 2 .

[0046] Thus, the second passivation film 13 has a higher negative charge content, which can form a stronger negative charge field passivation, while the first passivation film 12 has a lower negative charge content, which can form a weaker negative charge field passivation. This avoids the formation of inversion cancellation at the connection interface, forming a high recombination center, and improving the passivation effect of the battery.

[0047] In some embodiments, the second passivation film 13 includes one or more of an alumina film and a Lewis acidic substance film. Of course, the specific structural arrangement of the second passivation film 13 includes, but is not limited to, the several arrangements listed above. The second passivation film 13 is set accordingly according to actual use needs, and no specific limitation is made here.

[0048] Understandably, by setting one or more of the aluminum oxide film or Lewis acidic material film, the charge type of the first passivation film 12 can be negative and the charge density can be large, forming a strong negative charge type field passivation.

[0049] In some embodiments, the second passivation film 13 includes an aluminum oxide film with a thickness of 10 nm to 200 nm in the lateral direction; the lateral direction is the direction from the silicon substrate to the cut surface. For example, the thickness of the aluminum oxide film in the lateral direction can be any value between 10 nm, 50 nm, 100 nm, 150 nm, 200 nm or 10 nm to 200 nm, and is not limited herein.

[0050] Thus, the thickness of the alumina film in the lateral direction is within a suitable range. This avoids the passivation effect from being too small, which would reduce minority carrier lifetime and impair battery efficiency. It also avoids the marginal effect of the passivation effect from being too large, which would increase the processing time and material consumption.

[0051] In practical applications, the silicon substrate 11 can be placed in the first reaction chamber, and a precursor can be introduced into the first reaction chamber to form an aluminum oxide film in the first region of the silicon substrate 11.

[0052] The precursors may include TMA, water vapor, and ozone; the first reaction chamber may be an ALD device chamber.

[0053] In some embodiments, before forming the second passivation film 13, a mask can be used to cover all surfaces except the cut surface 113, leaving only the cut surface 113 exposed. This helps to prevent the formation process of the second passivation film 13 from causing contamination or damage to other surfaces.

[0054] In some embodiments, the second passivation film 13 comprises a Lewis acid material film, the thickness of which in the lateral direction is 500 nm to 5000 nm. For example, the thickness of the Lewis acid material film in the lateral direction can be any value between 500 nm, 1000 nm, 2000 nm, 3000 nm, 4000 nm, 5000 nm, or 500 nm to 5000 nm, and is not limited herein.

[0055] Lewis acidic substances can include, but are not limited to, metal ions, fullerenes, and Brønsted acidic hydrates. Most Lewis acidic substances react with water as a solvent to form hydrates with Brønsted acidity.

[0056] In practical applications, Lewis acidic substances can be dissolved in a suitable solvent to prepare a passivating agent solution. This solution is then uniformly coated onto the second region of the cut surface 113 using spin coating. After annealing or other treatments, the passivating agent interacts with the silicon substrate 11, forming a Lewis acidic substance film as a second passivation film 13 in the second region of the cut surface 113. For example, PCBM fullerene derivatives can be dissolved in organic solvents such as chlorobenzene to prepare a solution of a certain concentration, which is then spin-coated onto the silicon substrate 11. Of course, the above coating method can also be spraying or cross-sectional wetting, etc., and is not limited here.

[0057] Alternatively, a Lewis acidic material film can be formed in the second region of the cut surface 113 as a second passivation film 13 by methods such as vapor deposition and in-situ doping, which is not limited here.

[0058] Thus, the thickness of the Lewis acid material film in the lateral direction is within a suitable range. This avoids the passivation effect from being reduced, the minority carrier lifetime from being reduced, and the battery efficiency from being damaged due to the thickness of the Lewis acid material film in the lateral direction being too small. It also avoids the marginal effect of the passivation effect from being too large in the lateral direction, which would increase the processing time and material consumption.

[0059] In some embodiments, when the charge type of the first passivation film 12 is positive, the first passivation film 12 includes one or more of silicon nitride film, silicon oxynitride film, and silicon oxide film. Of course, when the charge type of the first passivation film 12 is positive, the specific structural arrangement of the first passivation film 12 includes, but is not limited to, the several arrangements listed above. The first passivation film 12 is set accordingly according to actual use needs, and no specific limitation is made here.

[0060] Understandably, silicon nitride films, silicon oxynitride films, and silicon oxide films can form positive charge passivation, which can avoid the formation of inversion cancellation at the passivation film interface, forming high recombination centers and optimizing the passivation effect of solar cell 10.

[0061] In some embodiments, the charge type of the first passivation film 12 is negative; the first passivation film 12 includes one or more of silicon nitride film, silicon oxynitride film, and silicon oxide film, as well as aluminum oxide film. Of course, when the charge type of the first passivation film 12 is negative, the specific structural arrangement of the first passivation film 12 includes, but is not limited to, the several arrangements listed above. The first passivation film 12 is set accordingly according to actual use needs, and no specific limitation is made here.

[0062] Understandably, by setting one or more of silicon nitride film, silicon oxynitride film and silicon oxide film, and aluminum oxide film, the charge type of the first passivation film 12 can be negative and the charge density is small, forming a weaker negative charge type field passivation.

[0063] Preferably, the first passivation film 12 includes an aluminum oxide film and a silicon nitride film; the silicon nitride film is located on the side of the aluminum oxide film opposite to the silicon substrate 11.

[0064] Understandably, employing a composite passivation structure of alumina and silicon nitride films, with the silicon nitride film located outside the alumina film, serves two purposes. First, it ensures that the first passivation film 12 has a negative charge type and a low charge density, resulting in a weaker negative charge type field passivation. Second, the alumina film provides excellent chemical passivation, reducing the surface recombination rate; the silicon nitride film enhances physical protection, while its high refractive index improves optical anti-reflection effects, thereby increasing battery conversion efficiency.

[0065] In some embodiments, when the first passivation film 12 comprises an aluminum oxide film and a silicon nitride film, the thickness of the aluminum oxide film in the lateral direction is 1.8 nm to 9 nm. For example, the thickness of the aluminum oxide film in the lateral direction can be any value between 1.8 nm, 2 nm, 3 nm, 4 nm, 5 nm, 6 nm, 7 nm, 8 nm, 9 nm or 1.8 nm to 9 nm, and is not limited herein.

[0066] Thus, the thickness of the alumina film in the lateral direction is within a suitable range. This avoids the passivation effect from being too small, which would reduce minority carrier lifetime and impair battery efficiency. It also avoids the marginal effect of the passivation effect from being too large, which would increase the processing time and material consumption.

[0067] In some embodiments, when the first passivation film 12 comprises an aluminum oxide film and a silicon nitride film, the thickness of the silicon nitride film in the lateral direction is 75 nm to 155 nm. For example, the thickness of the silicon nitride film in the lateral direction can be any value between 75 nm, 95 nm, 115 nm, 135 nm, 155 nm, or 75 nm to 155 nm, and is not limited herein.

[0068] Thus, the thickness of the silicon nitride film in the lateral direction is within a suitable range. This avoids the situation where the thickness of the silicon nitride film in the lateral direction is too small, which would lead to a decrease in passivation effect, low positive charge density at the interface, weak field effect passivation, and impaired battery efficiency. It also avoids the situation where the thickness of the silicon nitride film in the lateral direction is too large, which would reduce the marginal effect of passivation and increase the process time and material consumption.

[0069] In practical applications, the silicon substrate 11 can be placed in the first reaction chamber and a precursor can be introduced into the first reaction chamber to form an aluminum oxide film in the first region of the silicon substrate 11. Further, the silicon substrate 11 coated with the aluminum oxide film can be placed in the second reaction chamber and silane and ammonia can be introduced into the second reaction chamber to deposit a silicon nitride film on the aluminum oxide film, forming a first passivation film 12 including the aluminum oxide film and the silicon nitride film.

[0070] The precursors may include TMA, water vapor, and ozone; the first reaction chamber may be an ALD equipment chamber; and the second reaction chamber may be a PECVD equipment chamber.

[0071] In some embodiments, before forming the first passivation film 12, a mask can be used to cover all surfaces except the cut surface 113, leaving only the cut surface 113 exposed. This helps to prevent the formation process of the first passivation film 12 from causing contamination or damage to other surfaces.

[0072] It should be noted that the fabrication order of the first passivation film 12 and the second passivation film 13 can be set as needed. For example, the first passivation film 12 can be fabricated first, followed by the second passivation film 13; or, the second passivation film 13 can be fabricated first, followed by the first passivation film 12; there is no restriction here.

[0073] In some embodiments, the size ratio of the first passivation film 12 and the second passivation film 13 in the thickness direction of the silicon substrate 11 is 1:5 to 1:30; for example, the size ratio of the first passivation film 12 and the second passivation film 13 in the thickness direction of the silicon substrate 11 can be any value between 1:5, 1:10, 1:15, 1:20, 1:25, 1:30 or 1:5 to 1:30, and is not limited herein.

[0074] Thus, the size ratio of the first passivation film 12 and the second passivation film 13 in the thickness direction of the silicon substrate 11 is within a suitable range. This avoids the situation where the size ratio of the first passivation film 12 and the second passivation film 13 in the thickness direction of the silicon substrate 11 is too small, resulting in the first passivation film 12 having an excessively small size ratio, which would easily lead to inversion cancellation at the passivation film connection interface and the formation of a high recombination center. It also avoids the situation where the size ratio of the first passivation film 12 and the second passivation film 13 in the thickness direction of the silicon substrate 11 is too large, which would prevent the carrier recombination loss from being effectively reduced.

[0075] In some embodiments, the dimension of the first passivation film 12 in the thickness direction of the silicon substrate 11 is 5 μm to 40 μm. For example, the dimension of the first passivation film 12 in the thickness direction of the silicon substrate 11 can be any value between 5 μm, 10 μm, 20 μm, 30 μm, 40 μm or 5 μm to 40 μm, and is not limited herein.

[0076] Thus, the size of the first passivation film 12 in the thickness direction of the silicon substrate 11 is within a suitable range, which can avoid the first passivation film 12 being too small in the thickness direction of the silicon substrate 11, which would easily lead to inversion cancellation at the passivation film connection interface and the formation of high recombination centers; it can also avoid the first passivation film 12 being too large in the thickness direction of the silicon substrate 11, which would make it impossible to effectively reduce carrier recombination losses.

[0077] In some embodiments, the dimension of the second passivation film 13 in the thickness direction of the silicon substrate 11 is 60 μm to 155 μm. For example, the dimension of the second passivation film 13 in the thickness direction of the silicon substrate 11 can be any value between 60 μm, 80 μm, 100 μm, 120 μm, 140 μm, 155 μm or 60 μm to 155 μm, and is not limited herein.

[0078] Thus, the size of the second passivation film 13 in the thickness direction of the silicon substrate 11 is within a suitable range, which can avoid the second passivation film 13 being too small in the thickness direction of the silicon substrate 11, which would prevent it from effectively reducing carrier recombination loss; it can also avoid the first passivation film 12 being too large in the thickness direction of the silicon substrate 11, which would easily form inversion cancellation at the passivation film connection interface and form a high recombination center.

[0079] In some embodiments, the dimension of the third region in the thickness direction of the silicon substrate 11 is 0.2 μm to 3 μm. For example, the dimension of the third region in the thickness direction of the silicon substrate 11 can be any value between 0.2 μm, 0.4 μm, 0.6 μm, 0.8 μm, 1 μm, 1.5 μm, 2 μm, 3 μm or 0.2 μm to 3 μm, and is not limited herein.

[0080] Thus, the size of the third region in the thickness direction of the silicon substrate 11 is within a suitable range, which can avoid the situation where the size of the third region in the thickness direction of the silicon substrate 11 is too small, which would make it impossible to effectively prevent carrier recombination between the first passivation film 12 and the second passivation film 13, thereby causing recombination loss; it can also avoid the situation where the size of the third region in the thickness direction of the silicon substrate 11 is too large, which would make it easy to form inversion cancellation at the passivation film connection interface, forming a high recombination center.

[0081] It should be noted that the solar cell 10 provided in the embodiments of this application can be a bifacial solar cell 10, a back-contact solar cell 10, etc., and is not limited thereto.

[0082] It should be noted that, in the case of a back-contact solar cell 10, the P-region and the N-region are located on the same side of the silicon substrate 11. The first side 111 of the silicon substrate 11 is the light-facing side of the back-contact solar cell 10, and the second side 112 of the silicon substrate 11 is the back-facing side of the back-contact solar cell 10. Both the P-region and the N-region are located on the second side 112 of the silicon substrate 11. The P-region and the N-region are isolated from each other by an isolation region.

[0083] In some embodiments, the solar cell 10 is a back-contact solar cell 10, and the solar cell 10 further includes a P-type doped layer and an N-type doped layer, which are alternately arranged on the second surface 112.

[0084] In some embodiments, the solar cell 10 is a bifacial solar cell 10, and the solar cell 10 further includes a P-type doped layer and an N-type doped layer, wherein the P-type doped layer is disposed on the first surface 111 and the N-type doped layer is disposed on the second surface 112.

[0085] The P-type and N-type doped layers can be doped polycrystalline silicon layers. The N-type doped layer is doped with an N-type element, specifically a group VA element of the periodic table, such as phosphorus. The P-type doped layer is doped with a P-type element, specifically a group IIIA element of the periodic table, such as boron.

[0086] In some embodiments, the silicon substrate 11 is an N-type silicon substrate 11. Compared to an intrinsically conductive substrate, the N-type silicon substrate 11 has higher conductivity, which helps to reduce the series resistance of the solar cell 10 and improve the efficiency of the solar cell 10. Structurally, the first surface 111 of the solar cell 10 can be textured to improve the light-trapping effect of the light-facing surface of the solar cell 10, thereby improving the light utilization rate of the solar cell 10. Of course, the first surface 111 of the solar cell 10 can also be a flat polished surface; no specific limitation is made here.

[0087] In some embodiments, the first surface 111 and the second surface 112 further include a non-side passivation film; the non-side passivation film is disposed on the side of the P-type doped layer and the N-type doped layer away from the silicon substrate 11.

[0088] In one embodiment of the present invention, the non-side passivation film is one or more combinations of an oxide layer, a silicon carbide layer, and an amorphous silicon layer. As examples of the present invention, the non-side passivation film can be an oxide layer of a single material, a combination of oxide layers of multiple materials and amorphous silicon layers, or a combination of multiple layers of amorphous silicon with different refractive indices of a single material. Furthermore, the non-side passivation film can also be a silicon oxynitride layer, a silicon nitride layer, etc. It is understood that the specific structural arrangement of the non-side passivation film includes, but is not limited to, the several methods listed above. The non-side passivation film is configured according to actual usage needs, and no specific limitations are made here.

[0089] It is understood that in such embodiments, the photovoltaic module corresponding to the solar cell 10 may further include a metal frame, a backsheet, photovoltaic glass, and an encapsulating film. The encapsulating film can be filled between the front and back of the solar cell 10, the photovoltaic glass, adjacent cells, etc. As a filler, it can be a transparent colloid with good light transmittance and aging resistance. For example, the encapsulating film can be an EVA film or a POE film, and the specific choice can be made according to the actual situation, without limitation.

[0090] Photovoltaic glass can be applied to the encapsulating film on the front side of the solar cell 10. The photovoltaic glass can be ultra-clear glass, which has 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.

[0091] 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, etc. The specific choice depends on the specific circumstances and is not limited here. 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 photovoltaic module, providing stable support and installation. For example, the photovoltaic module can be installed at the desired location using the metal frame.

[0092] The photovoltaic system of this application embodiment includes the photovoltaic module described above.

[0093] 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 photovoltaic modules; for example, multiple photovoltaic 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.

[0094] 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 application. 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.

[0095] Furthermore, the above are merely preferred embodiments of this application and are not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the scope of protection of this application.

Claims

1. A solar cell, characterized in that, It includes a silicon substrate, a first passivation film, and a second passivation film. The silicon substrate includes a first surface and a second surface opposite to each other, and a plurality of cut surfaces connecting the first surface and the second surface. The cutting surface includes a first region near the first surface and a second region near the second surface; The first passivation film is disposed in the first region, and the second passivation film is disposed in the second region; The charge characteristics of the first passivation film are different from those of the second passivation film; the charge characteristics are charge type or charge density.

2. The solar cell according to claim 1, characterized in that, The charge type of the first passivation film is positive or negative; the charge type of the second passivation film is negative; when the charge type of the first passivation film is negative; the charge density of the first passivation film is less than the charge density of the second passivation film.

3. The solar cell according to claim 2, characterized in that, The second passivation film includes an aluminum oxide film or a Lewis acidic material film.

4. The solar cell according to claim 3, characterized in that, The thickness of the alumina film in the lateral direction is 10nm~200nm; the lateral direction is the direction from the silicon substrate to the cut surface.

5. The solar cell according to claim 3, characterized in that, The thickness of the Lewis acidic material film in the lateral direction is 500nm~5000nm; the lateral direction is the direction from the silicon substrate to the cut surface.

6. The solar cell according to claim 2, characterized in that, The first passivation film has a positive charge; the first passivation film includes one or more of silicon nitride film, silicon oxynitride film and silicon oxide film.

7. The solar cell according to claim 2, characterized in that, The first passivation film has a negative charge type; the first passivation film includes one or more of silicon nitride film, silicon oxynitride film and silicon oxide film, and aluminum oxide film.

8. The solar cell according to claim 7, characterized in that, The first passivation film includes an aluminum oxide film and a silicon nitride film; the silicon nitride film is located on the side of the aluminum oxide film opposite to the silicon substrate.

9. The solar cell according to claim 8, characterized in that, The thickness of the alumina film in the lateral direction is 1.8 nm to 9 nm; the lateral direction is the direction from the silicon substrate to the cut surface.

10. The solar cell according to claim 8, characterized in that, The thickness of the silicon nitride film in the lateral direction is 75nm to 155nm; the lateral direction is the direction in which the silicon substrate points to the cut surface.

11. The solar cell according to claim 1, characterized in that, The size ratio of the first passivation film and the second passivation film in the thickness direction of the silicon substrate is 1:5 to 1:

30.

12. The solar cell according to claim 1, characterized in that, The first passivation film has a thickness dimension of 5 μm to 40 μm in the silicon substrate.

13. The solar cell according to claim 1, characterized in that, The second passivation film has a thickness dimension of 60 μm to 155 μm in the silicon substrate.

14. The solar cell according to claim 1, characterized in that, The solar cell further includes a P-type doped layer and an N-type doped layer, wherein the P-type doped layer is disposed on the first surface and the N-type doped layer is disposed on the second surface.

15. The solar cell according to claim 1, characterized in that, The solar cell further includes a P-type doped layer and an N-type doped layer, which are alternately arranged on the second surface.

16. The solar cell according to claim 1, characterized in that, The cutting surface also includes a third region located between the first region and the second region; the third region is used to isolate the first region and the second region.

17. A photovoltaic module, characterized in that, Including the solar cell as described in any one of claims 1-16.

18. A photovoltaic system, characterized in that, Including the photovoltaic module as described in claim 17.

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