Solar cell, cell assembly and photovoltaic system

Abstract

The utility model is suitable for the technical field of solar cells, and provides a solar cell, a cell assembly and a photovoltaic system. The solar cell comprises a plurality of front metal electrodes, a silicon substrate, a back structure and a plurality of back metal electrodes, the back surface structure comprises a plurality of polishing areas and a plurality of suede areas which are alternately arranged; wherein the suede area is arranged between any two polishing areas, and the back metal electrodes are arranged in the polishing areas. According to the utility model, the suede area is arranged on the back surface structure of the solar cell, and the back surface metal electrode is arranged in the polishing area, so that when light enters the back surface structure, the light is scattered and reflected for multiple times in the concave-convex structure of the suede area, thereby increasing the path length of the light in the solar cell, and improving the brightness of the solar cell. The photoelectric conversion efficiency and the light absorption efficiency of the solar cell are improved, and the power generation rate of the cell assembly is improved.

Description

[0001] This application claims priority to Chinese patent application number 2024113903274, entitled “Solar Cells, Battery Components and Photovoltaic Systems”, filed with the China Patent Office on September 30, 2024, the entire contents of which are incorporated herein by reference. Technical Field

[0002] The utility model relates to the technical field of solar cells, in particular to a solar cell, a battery assembly and a photovoltaic system. Background Art

[0003] A solar cell is a device that converts sunlight into electricity using the photoelectric effect. Made primarily of photovoltaic materials (such as silicon), it absorbs photons and excites electrons, generating an electric current. The cell, consisting of a front electrode, a photovoltaic layer, and a back electrode, generates electricity when exposed to sunlight and is widely used in power generation systems and various electronic devices.

[0004] Current solar cell designs typically employ a fully polished back surface. While this design can enhance back-side passivation, it also makes it difficult to further increase photoelectric conversion efficiency. Utility Model Content

[0005] The utility model provides a solar cell, a battery assembly and a photovoltaic system to solve the problem in the prior art that the photoelectric conversion efficiency of solar cells is difficult to further improve.

[0006] The present invention is implemented as follows: a solar cell, a solar cell assembly, and a photovoltaic system are provided. The solar cell comprises a plurality of front metal electrodes, a silicon substrate, a back structure, and a plurality of back metal electrodes stacked in sequence; the back structure comprises a plurality of polished regions and a plurality of velvet regions arranged alternately; wherein the velvet region is arranged between any two polished regions, and the back metal electrodes are arranged in the polished regions.

[0007] Furthermore, in the textured area, a distance from the textured area to the back metal electrode is greater than 15 μm.

[0008] Furthermore, an absolute value of a height difference between the suede area and the polished area is 0.5 μm to 15 μm.

[0009] Furthermore, the textured area has a pyramid structure, and the height of the pyramid structure is 0.5 μm to 5 μm.

[0010] Furthermore, the back structure includes a back tunneling layer, a back doping layer, a first back passivation layer and a second back passivation layer stacked in sequence, and the back tunneling layer, the back doping layer, the first back passivation layer and the second back passivation layer are formed in the polishing area.

[0011] Furthermore, the back surface structure includes a first back surface passivation layer and a second back surface passivation layer stacked in sequence, and the first back surface passivation layer and the second back surface passivation layer are formed in the textured area.

[0012] An embodiment of the present invention further provides a battery assembly, which includes the solar cell as described above.

[0013] An embodiment of the present invention further provides a photovoltaic system, which includes the battery assembly described above.

[0014] The utility model is applicable to the technical field of solar cells, and provides a solar cell, a cell assembly, and a photovoltaic system. The solar cell includes a plurality of front metal electrodes, a silicon substrate, a back structure, and a plurality of back metal electrodes stacked in sequence; the back structure includes a plurality of polished areas and a plurality of velvet areas alternately arranged; wherein the velvet area is arranged between any two of the polished areas, and the back metal electrodes are arranged in the polished areas. The utility model provides a velvet area on the back structure of the solar cell, and the back metal electrodes are arranged in the polished areas. When light enters the back structure, it will be scattered and reflected multiple times in the concave-convex structure of the velvet area, thereby increasing the path length of light inside the solar cell, improving the photoelectric conversion efficiency and light absorption efficiency of the solar cell, and improving the power generation rate of the cell assembly. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments recorded in the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0016] Figure 1 This is a schematic diagram of a module of a photovoltaic system provided by an embodiment of the present utility model;

[0017] Figure 2 This is a schematic diagram of a module of a battery assembly provided by an embodiment of the present utility model;

[0018] Figure 3 A schematic diagram of the hierarchical structure of a solar cell provided in an embodiment of the present utility model;

[0019] Figure 4 for Figure 3 A partial plan view of the back surface structure of the solar cell;

[0020] Figure 5 for Figure 3 Schematic diagram of the height difference between the textured area and the polished area in the solar cell.

[0021] Explanation of main component symbols: 1000, photovoltaic system; 1001, battery assembly; 100, solar cell; 10, front metal electrode; 20, front structure; 30, silicon substrate; 40, back structure; 50, back metal electrode; 21, front passivation layer; 22, front doping layer; 41, polished area; 42, velvet area; 411, back tunneling layer; 412, back doping layer; 413, first back passivation layer; 414, second back passivation layer; 421, third back passivation layer; 422, fourth back passivation layer; 423, pyramid structure. DETAILED DESCRIPTION

[0022] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be understood as limiting the present invention. In addition, it should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0023] In the description of the present invention, it should be understood that the terms "length", "width", "up", "down", "top", "bottom", "horizontal", "longitudinal", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they cannot be understood as a limitation on the present invention.

[0024] 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 the technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the described features. In the description of this utility model, "plurality" means two or more, unless otherwise specifically defined.

[0025] In the description of this utility model, it should be noted that, unless otherwise expressly specified or limited, the terms "installed," "connected," and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; mechanical connections, electrical connections, or mutual communication; direct connections or indirect connections through an intermediate medium; and internal communication between two components or interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in this utility model based on specific circumstances.

[0026] In the present invention, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may include the first and second features being in direct contact, or may include the first and second features being in contact not directly but through another feature between them. Moreover, a first feature being "above," "above," and "above" a second feature may include the first feature being directly above or obliquely above the second feature, or may simply mean that the first feature is higher in level than the second feature. A first feature being "below," "below," and "below" a second feature may include the first feature being directly below or obliquely below the second feature, or may simply mean that the first feature is lower in level than the second feature.

[0027] The disclosure below provides many different embodiments or examples for realizing different structures of the present invention. In order to simplify the disclosure of the present invention, the components and settings of specific examples are described below. Of course, they are merely examples and are not intended to limit the present invention. In addition, the present invention may repeat reference numbers and / or reference letters in different examples. Such repetition is for the purpose of simplicity and clarity and does not in itself indicate the relationship between the various embodiments and / or settings discussed. In addition, the present invention provides examples of various specific processes and materials, but a person of ordinary skill in the art may be aware of the application of other processes and / or the use scenarios of other materials.

[0028] See also Figure 1 and Figure 2 The photovoltaic system 1000 in the embodiment of the present invention may include a battery assembly 1001 in the embodiment of the present invention. The battery assembly 1001 in the embodiment of the present invention may include multiple battery strings, and the battery string may include multiple solar cells 100 in the embodiment of the present invention. In the present invention, the multiple solar cells 100 in the battery assembly 1001 are sequentially connected in series via welding ribbons to form a battery string. The individual battery strings in the battery assembly 1001 can be connected in series, in parallel, or in a combination of series and parallel to achieve current bus output. For example, the battery strings can be connected via bus bars.

[0029] See also Figure 3 、 Figure 4 and Figure 5 The solar cell 100 in the embodiment of the present invention can be a whole cell, or it can be a half cell, a third cell, or a cell with other proportions divided from a whole cell. It should be noted that the drawings provided in this application are schematic diagrams, and some elements are not shown in the drawings. The purpose is to clearly describe the technical solution and highlight the key points of the utility model. It is not intended to limit the technical solution to not including these unshown elements. In other words, the drawings are only examples and do not represent a limitation on the specific form of the solar cell 100.

[0030] Furthermore, if Figure 3 、 Figure 4 and Figure 5 As shown, the solar cell 100 includes a plurality of front metal electrodes 10, a front structure 20, a silicon substrate 30, a back structure 40, and a plurality of back metal electrodes 50 stacked in sequence. The solar cell 100 of the embodiment of the present invention may specifically be a TOPCon solar cell 100, and the front metal electrode 10 and the back metal electrode 50 may specifically be composed of electrodes of a single polarity or electrodes of two polarities. The solar cell 100 of the embodiment of the present invention specifically has a front structure 20 and a back structure 40, which are arranged opposite to each other and respectively arranged on both sides of the silicon substrate 30, the back structure 40 is arranged on the back side of the silicon substrate 30, and the front structure 20 is arranged on the front side of the silicon substrate 30. The front metal electrode 10 is arranged on the front structure 20, and the back metal electrode 50 is arranged on the back structure 40, and the polarities of the front metal electrode 10 and the back metal electrode 50 are opposite. The front structure 20 is a velvet structure that has been textured, specifically including a front passivation layer 21 and a front doping layer 22 stacked in sequence. The front passivation layer 21 is a thin film or coating on the front of the solar cell 100 specifically used to reduce the surface recombination rate, reduce carrier recombination losses, and improve cell efficiency. The front doping layer 22 can be either P-type doped or N-type doped.

[0031] The back surface structure 40 includes a plurality of alternating polished regions 41 and a plurality of velvet regions 42. The velvet region 42 is disposed between any two polished regions 41, and the back surface metal electrode 50 is disposed within the polished region 41. The polished region 41 is a smooth, polished structure that has been polished. The velvet region 42 can be disposed between two adjacent polished regions 41 or between two non-adjacent polished regions.

[0032] The textured areas 42 are areas that have undergone a texturing treatment. Texturing refers to the formation of micron-scale concave and convex structures (such as pyramidal, conical, or quadrangular pyramidal structures) on the surface of the silicon substrate 30 through chemical or physical means, thereby reducing surface reflectivity and improving light absorption efficiency. In the embodiment of the present invention, a textured surface is formed on the back surface structure 40 of the solar cell 100 by texturing, thereby forming a plurality of textured areas 42.

[0033] Specifically, the back metal electrode 50 is disposed in the polished region 41, and the projection of the back metal electrode 50 on the back structure 40 is located in the polished region 41. That is, for the back structure 40, the surface of the polished region 41 is a polished surface, and the surface of the velvet region 42 is a velvet surface. That is, the roughness of the velvet region 42 is greater than that of the polished region 41, and the smoothness of the polished region 41 is greater than that of the velvet region 42. Furthermore, the polished region 41 is disposed in the location corresponding to the back structure 40, and near the back metal electrode 50, while the velvet region 42 is disposed outside the polished region 41.

[0034] In conventional solar cells 100, the entire back structure 40 is polished, meaning the entire back structure 40 is polished. However, in the present invention, in addition to the polished area 41, the back structure 40 is also provided with a velvet area 42. The velvet area 42 is a velvet structure with a micron- or nanometer-scale uneven surface. This surface can effectively reduce light reflection. When light enters the back structure 40, it is scattered and reflected multiple times in the uneven structure of the velvet area 42, thereby increasing the path length of light within the solar cell 100, improving the photoelectric conversion efficiency and light absorption efficiency of the solar cell 100, and improving the power generation efficiency of the battery assembly 1001. Furthermore, the provision of the velvet area 42 can also allow more photons to be absorbed by the active area of ​​the solar cell 100, increasing the number of electron-hole pairs and improving the photoelectric conversion efficiency. Furthermore, the provision of the velvet area 42 on the back of the solar cell 100 can effectively reduce the area of ​​the back doping layer 412 on the back of the solar cell 100, reducing its parasitic absorption and the composite loss of the back polished area 41. Therefore, by setting a velvet area 42 on the back structure 40 of the solar cell 100 and setting the back metal electrode 50 in the polished area 41, the photoelectric conversion efficiency and light absorption efficiency of the solar cell 100 can be improved, the power generation rate of the battery component 1001 can be improved, and the recombination loss of the solar cell 100 can be reduced.

[0035] Furthermore, if Figure 3As shown, the back structure 40 includes a back tunneling layer 411, a back doping layer 412, a first back passivation layer 413 and a second back passivation layer 414 stacked in sequence, and the back tunneling layer 411, the back doping layer 412, the first back passivation layer 413 and the second back passivation layer 414 are formed in the polishing area 41.

[0036] Specifically, in the embodiment of the present invention, each functional layer is stacked in sequence to form a polishing area 41, which can form a multi-layer composite structure that complements each other in terms of electrical and optical properties. The second back passivation layer 414 refers to a thin film or coating on the back of the solar cell 100 that is specifically used to reduce the surface recombination rate, reduce carrier recombination losses, and improve battery efficiency. The first back passivation layer 413 is a thin film layer used to isolate and separate different functional areas in the manufacture of the solar cell 100. It can reduce the recombination rate of the surface of doped polysilicon and can have a passivation effect. The first back passivation layer 413 can specifically be an Al2O3 thin film formed by ALD deposition.

[0037] In the present invention, the multi-layer structure design of the polished region 41 can significantly improve the electrical and optical performance of the back surface of the solar cell 100. By introducing the back tunneling layer 411, the back doping layer 412, the first back passivation layer 413, and the second back passivation layer 414, an optimized current transmission path and an efficient optical interface can be formed in the back structure 40, thereby improving the overall photoelectric conversion efficiency and long-term stability of the solar cell 100.

[0038] Furthermore, if Figure 3 and Figure 4 As shown, for the specific structure of the velvet area 42, the back structure 40 includes a third back passivation layer 421 and a fourth back passivation layer 422 stacked in sequence, and the third back passivation layer 421 and the fourth back passivation layer 422 are formed in the velvet area 42. The third back passivation layer 421 is a thin film layer used to isolate and separate different functional areas in the manufacture of the solar cell 100. It can play a passivation effect and can reduce the recombination rate of the surface of the doped polysilicon. The third back passivation layer 421 can specifically be an Al2O3 film formed by ALD deposition. In addition, the first back passivation layer 413 and the third back passivation layer 421 can specifically be integrally formed, and the second back passivation layer 414 and the fourth back passivation layer 422 can specifically be integrally formed.

[0039] The fourth back passivation layer 422 is a thin film or coating applied to the back of the solar cell 100 specifically for reducing the surface recombination velocity, minimizing carrier recombination losses, and improving cell efficiency. It also reduces back optical reflection and increases back optical absorption. Specifically, by adding the fourth back passivation layer 422 to the velvet region 42, the photoelectric conversion efficiency of the solar cell 100 can be significantly enhanced, recombination losses can be reduced, and the cell's stability can be improved.

[0040] Furthermore, if Figure 3 and Figure 4 As shown, for the specific setting of the velvet area 42, in the velvet area 42, the distance L1 from the velvet area 42 to the back metal electrode 50 is greater than 15μm. Specifically, because the velvet area 42 is specifically a velvet structure, when the metal electrode is in direct contact with the velvet area 42, due to the presence of a large number of microscopic concave-convex structures on the velvet surface, the contact resistance will increase, thereby reducing the current collection efficiency. Therefore, in an embodiment of the present utility model, it is designed to maintain a certain distance between the back metal electrode 50 and the velvet area 42, that is, the distance L1 from the velvet area 42 to the back metal electrode 50 is greater than 15μm. This can avoid direct contact between the back metal electrode 50 and the velvet area 42, ensure that the back metal electrode 50 is mainly in contact with the polishing area 41, thereby reducing contact loss, and achieving the effect of improving the power generation rate and electrical performance of the solar cell 100.

[0041] Moreover, the velvet area 42 of the velvet structure will produce higher local thermal stress and mechanical stress than the polished area 41 of the polished structure due to its uneven surface morphology. If the metal electrode directly covers or is close to the boundary of the velvet area 42, then during the subsequent high-temperature sintering or electrode curing process, it may cause local film peeling or crack expansion, causing the "film burst" phenomenon. Therefore, in the velvet area 42, the distance L1 from the velvet area 42 to the back metal electrode 50 is set to be greater than 15μm, that is, the distance between the velvet area 42 and the back metal electrode 50 is kept greater than 15μm, which can effectively reduce the risks of film stress concentration, uneven thermal expansion, film peeling, etc., and avoid the "film burst" phenomenon caused by excessive local stress, thereby achieving the effect of improving the process reliability and overall performance stability of the solar cell 100.

[0042] Preferably, the distance L1 from the velvet area 42 to the back metal electrode 50 can be set to 16 μm, 20 μm, 25 μm, 30 μm, or 40 μm, thereby preventing the solar cell 100 from “bursting” to the greatest extent.

[0043] Furthermore, if Figure 3 and Figure 4 and Figure 5As shown, for the specific structure of the suede area 42, the absolute value of the height difference L2 between the suede area 42 and the polished area 41 is 0.5μm to 15μm. Specifically, the height difference L2 between the suede area 42 and the polished area 41 refers to the distance from the protrusion of the suede area 42 to the surface of the polished area 41.

[0044] Specifically, the velvet region 42 is recessed relative to the polished region 41. This is because when the back structure 40 is textured to form the velvet region 42, the battery material is corroded and removed. The corrosion process is typically uneven, resulting in a recessed surface structure. Therefore, the velvet region 42 is thinner than the polished region 41, giving the appearance of being recessed.

[0045] Furthermore, the depth of the depression in the velvet area 42 can directly affect the scattering and absorption effects of light. Therefore, by setting the absolute value of the height difference L2 between the velvet area 42 and the polished area 41 within the range of 0.5 μm to 15 μm, multiple reflections of light can be effectively controlled, allowing light to be scattered more times on the surface of the solar cell 100, increasing the propagation path of light inside the solar cell 100, thereby achieving the effect of improving the power generation rate and light absorption efficiency of the solar cell 100, and further improving the battery efficiency of the solar cell 100. Preferably, the absolute value of the height difference L2 between the velvet area 42 and the polished area 41 can be set to 0.5 μm, 1 μm, 5 μm, 8 μm, 10 μm, or 15 μm, thereby maximizing the light absorption efficiency of the solar cell 100.

[0046] Furthermore, if Figure 3 、 Figure 4 and Figure 5 As shown, for the specific structure of the velvet area 42, the velvet area 42 has a pyramid structure 423, and the height L3 of the pyramid structure 423 is 0.5μm to 5μm. Specifically, the pyramid structure 423 is a microstructure with excellent anti-reflection properties. When light is irradiated on the surface of the pyramid structure 423 of the velvet area 42, multiple scattering, refraction and reflection will occur between the multiple faces of the pyramid structure 423. This multiple change in the light path can effectively reduce the light reflection loss on the surface of the solar cell 100, thereby further achieving the effect of improving the light absorption efficiency of the solar cell 100 and further improving the battery efficiency of the solar cell 100. Preferably, the height L3 of the pyramid structure 423 of the velvet area 42 can be set to 0.5μm, 1μm, 1.5μm, 2μm, 2.5μm, 3μm, 3.5μm, 4μm, 4.5μm, 5μm, thereby maximizing the light absorption efficiency of the solar cell 100.

[0047] Furthermore, if Figure 3and Figure 4 As shown, the polishing area 41 is configured as a region that has undergone laser patterning. Specifically, laser patterning has a very high spatial resolution, down to the micron level. This precision allows for precise control of the boundaries and shape of the polishing area when forming it. Therefore, laser patterning allows for specific patterning of the polishing area 41, allowing for precise control of the extent of the polishing area 41 and avoiding issues where the polishing area 41 is too small to fully cover the back metal electrode 50.

[0048] The following describes the manufacturing process of the solar cell 100 provided by the embodiment of the present invention. Figure 3 、 Figure 4 and Figure 5 As shown, first, a silicon substrate 30 is prepared, and the front and back surfaces of the silicon substrate 30 are surface treated by techniques such as chemical mechanical polishing (CMP) to improve the smoothness and cleanliness of the surface of the silicon substrate 30, remove defects and impurities, and prepare for subsequent processes.

[0049] Furthermore, the front and back sides of the silicon substrate 30 are textured by alkaline etching or other methods to form microstructures (such as pyramids) to enhance the light absorption capacity of the solar cell 100, reduce reflection, and improve the photoelectric conversion efficiency of the solar cell 100.

[0050] Furthermore, boron is doped on one or both sides of the silicon substrate 30. The specific doping concentration and distribution can be selected according to actual conditions.

[0051] Furthermore, the borosilicate glass formed on the side and back surfaces of the silicon substrate 30 due to boron doping is removed.

[0052] Furthermore, the back surface of the silicon substrate 30 is polished to ensure that the backlight surface of the silicon substrate 30 is smooth and to remove residual impurities.

[0053] Furthermore, a tunneling oxide layer (usually SiO) and intrinsic polysilicon or amorphous silicon are grown on the front and back sides of the silicon substrate 30 .

[0054] Furthermore, phosphorus is doped on the front and back surfaces of the silicon substrate 30. The specific doping concentration and distribution can be selected according to actual conditions.

[0055] Furthermore, the back side of the silicon substrate 30 is subjected to laser patterning, forming a patterned structure on the back side of the silicon substrate 30 using laser technology. The laser patterning of the back side of the silicon substrate 30 can correspond to the location where the back side metal electrode 50 is not present. The range of the laser patterning is slightly smaller than the range of the area where the back side metal electrode 50 is not present, ultimately forming a textured area 42, while the area where the back side metal electrode 50 is present remains as a polished area 41.

[0056] Furthermore, the phosphosilicate glass formed on the front surface of the silicon substrate 30 due to phosphorus doping is removed to prepare for subsequent processes.

[0057] Furthermore, the back of the silicon substrate 30 is textured, and subsequently, the front and back of the silicon substrate 30 are further cleaned with phosphosilicate glass and borosilicate glass. Finally, the front and back of the silicon substrate 30 are thin-film coated and metallized.

[0058] The manufacturing process of the solar cell 100 of the present invention is relatively simple. It only requires an additional step of laser patterning of the back surface in the conventional TOPCon solar cell 100 process.

[0059] Throughout this specification, reference to terms such as "some embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples" means that a specific feature, structure, material, or characteristic described in conjunction with an embodiment or example is included in at least one embodiment or example of the present application. In this specification, the illustrative use of the above terms does 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 any one or more embodiments or examples.

[0060] In addition, the above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present application should be included in the scope of protection of the present application.

Claims

1. A solar cell, characterized in that: It includes a plurality of front metal electrodes, a silicon substrate, a back structure, and a plurality of back metal electrodes stacked in sequence; The back surface structure includes a plurality of polished areas and a plurality of suede areas arranged alternately; The suede area is arranged between any two of the polishing areas, and the back metal electrode is arranged in the polishing area.

2. The solar cell according to claim 1, wherein In the textured area, a distance from the textured area to the back metal electrode is greater than 15 μm.

3. The solar cell according to claim 1, wherein An absolute value of a height difference between the textured area and the polished area is 0.5 μm to 15 μm.

4. The solar cell according to claim 1, wherein The textured region has a pyramid structure, and the height of the pyramid structure is 0.5 μm to 5 μm.

5. The solar cell according to claim 1, wherein The back structure includes a back tunneling layer, a back doping layer, a first back passivation layer and a second back passivation layer stacked in sequence, and the back tunneling layer, the back doping layer, the first back passivation layer and the second back passivation layer are formed in the polishing area.

6. The solar cell according to claim 1, wherein The back surface structure includes a third back surface passivation layer and a fourth back surface passivation layer stacked in sequence, and the third back surface passivation layer and the fourth back surface passivation layer are formed in the textured area.

7. A battery assembly, characterized in that: A solar cell comprising the solar cell according to any one of claims 1 to 6.

8. A photovoltaic system, characterized in that: A battery assembly comprising the battery assembly of claim 7.

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