Solar cell sheet, cell assembly and photovoltaic system

Abstract

The present application is applicable to the technical field of solar cells. Provided are a solar cell sheet (100), a cell assembly (200) and a photovoltaic system (1000). The solar cell sheet (100) may comprise a silicon substrate (10), first doped layers (20), second doped layers (30), first passivation film layers (40) and first solder joints (50), wherein the silicon substrate (10) has a first surface (11) and a second surface (12), which are opposite each other, the first doped layers (20) are arranged on the first surface (11) in a stacked manner, and each first doped layer (20) has several first preset regions (201); the second doped layers (30) are arranged in the first preset regions (201) in a stacked manner, and several second doped layers (30) are arranged at intervals; the first passivation film layers (40) are arranged on the second doped layers (30) and the first doped layers (20) in a stacked manner; and the first solder joints (50) are arranged on the first passivation film layers (40), and the orthographic projections of the first solder joints (50) on the first doped layers (20) at least partially overlap with the orthographic projections of the second doped layers (30) on the first doped layers (20).

Description

Solar cells, battery modules and photovoltaic systems

[0001] Priority information

[0002] This application claims priority and benefits of patent application No. 202311238243.4 filed with the State Intellectual Property Office of China on September 22, 2023, and patent application No. 202420802407.5 and No. 202420798601.0 filed with the State Intellectual Property Office of China on April 17, 2024, and the entire text of which is incorporated herein by reference. Technical Field

[0003] The present application relates to the technical field of solar cells, and in particular to a solar cell, a battery assembly and a photovoltaic system. Background Art

[0004] Currently, solar cells (such as Topcon solar cells, HJT solar cells, and back-contact solar cells) are all equipped with a doped layer. A fine grid and a main grid are also provided on the doped layer. The fine grid penetrates the passivation film layer and contacts the doped layer to collect current. The main grid is connected to the fine grid to collect the current of the fine grid. When connecting two solar cells, solder joints are required on the cell to solder to the solder ribbon. The solder joints are usually provided on the passivation film layer.

[0005] Utility Model Content

[0006] The present application provides a solar cell, a battery assembly and a photovoltaic system.

[0007] The solar cell of the embodiment of the present application comprises:

[0008] a silicon substrate having a first surface and a second surface opposite to each other;

[0009] A first doping layer stacked on the first surface, the first doping layer having a plurality of first preset areas;

[0010] A second doping layer is provided at the first preset area, wherein a plurality of the second doping layers are provided at intervals;

[0011] a first passivation film layer, the first passivation film layer being stacked on the second doping layer and the first doping layer; and

[0012] A plurality of first welding points are provided on the first passivation film layer, and an orthographic projection of the first welding points on the first doping layer at least partially overlaps with an orthographic projection of the second doping layer on the first doping layer.

[0013] The present application also provides a battery assembly, which includes a plurality of solar cells.

[0014] The present application also provides a photovoltaic system, which includes the above-mentioned battery assembly.

[0015] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become obvious from the description below, or will be learned through practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] FIG1 is a schematic diagram of a module of a photovoltaic system provided in an embodiment of the present application;

[0017] FIG2 is a schematic diagram of a module of a battery assembly provided in an embodiment of the present application;

[0018] FIG3 is a schematic structural diagram of a solar cell provided in an embodiment of the present application;

[0019] FIG4 is another structural schematic diagram of a solar cell provided in an embodiment of the present application;

[0020] FIG5 is another schematic structural diagram of a solar cell provided in an embodiment of the present application;

[0021] FIG6 is a schematic diagram of another structure of a solar cell provided in an embodiment of the present application;

[0022] FIG7 is a schematic diagram of a planar structure of a solar cell provided in an embodiment of the present application;

[0023] FIG8 is a schematic cross-sectional view of the back contact cell along line VI-VI in FIG7 ;

[0024] FIG9 is another schematic cross-sectional view of the back contact cell along line VI-VI in FIG7 ;

[0025] FIG10 is another schematic cross-sectional view of the back contact cell along line VI-VI in FIG7 ;

[0026] FIG11 is another schematic cross-sectional view of the back contact cell along line VI-VI in FIG7 ;

[0027] FIG12 is another schematic diagram of the planar structure of a solar cell provided in an embodiment of the present application;

[0028] FIG13 is a schematic cross-sectional view of the back contact cell along line IX-IX in FIG12;

[0029] FIG14 is a schematic cross-sectional view of the back contact cell along line XX in FIG12 ;

[0030] FIG15 is another schematic cross-sectional view of the back contact cell along line IX-IX in FIG12;

[0031] FIG16 is another schematic cross-sectional view of the back contact cell along line XX in FIG12 ;

[0032] FIG17 is another schematic diagram of the planar structure of the solar cell provided in an embodiment of the present application. Modes for Carrying Out the Invention

[0033] In order to make the objectives, technical solutions, and advantages of this application more clearly understood, the present application is further described in detail below with reference to the accompanying drawings and examples. 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. In addition, it should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.

[0034] In the description of this application, 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, and are only for the convenience of describing this application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on this application.

[0035] 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. Throughout the description of this application, "plurality" means two or more, unless otherwise specifically defined.

[0036] In the description of this application, 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; they can refer to mechanical connections, electrical connections, or mutual communication; they can refer to direct connections or indirect connections through an intermediate medium; they can refer to internal communication between two components or the interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on specific circumstances.

[0037] In this application, 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.

[0038] The disclosure below provides many different embodiments or examples for realizing different structures of the present application. In order to simplify the disclosure of the present application, the components and settings of specific examples are described below. Of course, they are merely examples and are not intended to limit the present application. In addition, the present application 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 application provides examples of various specific processes and materials, but those skilled in the art will appreciate the application of other processes and / or the use scenarios of other materials.

[0039] Referring to Figures 1 and 2, the photovoltaic system 1000 in the embodiment of the present application may include the battery assembly 200 in the embodiment of the present application. The battery assembly 200 in the embodiment of the present application may include a plurality of battery strings, and the battery string may include a plurality of solar cells 100 in the embodiment of the present application. In the present application, the multiple solar cells 100 in the battery assembly 200 are sequentially connected in series via welding ribbons to form a battery string. The individual battery strings in the battery assembly 200 can be connected in series, in parallel, or in a combination of series and parallel to achieve current bus output. For example, the connection between the individual battery strings can be achieved via bus bars.

[0040] 3 and 4 , the solar cell 100 in this embodiment may include a silicon substrate 10 , a first doping layer 20 , a second doping layer 30 , a first passivation film layer 40 and a first solder joint 50 .

[0041] The silicon substrate 10 has a first surface 11 and a second surface 12 opposite to each other. A first doped layer 20 is stacked on the first surface 11 and has a plurality of first predetermined regions 201. Second doped layers 30 are stacked in the first predetermined regions 201, and the plurality of second doped layers 30 are spaced apart.

[0042] The first passivation film layer 40 is stacked on the second doping layer 30 and the first doping layer 20. Specifically, the first passivation film layer 40 can cover the entire first doping layer 20 and the second doping layer 30 (that is, the first passivation film layer 40 covers the second doping layer 30 and the area of ​​the first doping layer 20 not covered by the second doping layer 30).

[0043] The first solder joint 50 can be disposed on the first passivation film layer 40, and the orthographic projection of the first solder joint 50 on the first doped layer 20 at least partially overlaps with the orthographic projection of the second doped layer 30 on the first doped layer 20. In other words, the first solder joint 50 is at least partially located above the second doped layer 30.

[0044] To put it another way, the first solder joint 50 and the second doped layer 30 at least partially overlap in the thickness direction of the solar cell 100. It should be noted that in this application, "orthographic projection" refers to the orthographic projection along the thickness direction of the solar cell 100. For similar descriptions below, please refer to this reference for clarity.

[0045] In the related art, the tension between the doping layer and the passivation film layer below the solder joint is relatively weak, and the solder joint is prone to detachment due to insufficient tension during soldering.

[0046] In the solar cell of the embodiment of the present application, a second doping layer 30 is provided on the first predetermined region 201 of the first doping layer 20. The second doping layer 30 is covered with a first passivation film 40. The orthographic projection of the first solder joint 50 on the first doping layer 20 at least partially overlaps with the orthographic projection of the second doping layer 30 on the first doping layer 20. Thus, by providing the second doping layer 30 on the first doping layer 20, the bonding strength with the first passivation film 40 can be enhanced. Disposing the first solder joint 50 above the second doping layer 30 (i.e., the orthographic projection of the first solder joint 50 on the first doping layer 20 at least partially overlaps with the orthographic projection of the second doping layer 30 on the first doping layer 20) can effectively increase the bonding strength of the first solder joint 50 during welding, thereby effectively preventing the first solder joint 50 from detaching during welding and improving welding reliability.

[0047] Specifically, in the present application, the solar cell 100 may be a back contact cell, a Topcon solar cell, an HJT solar cell, or the like having a first doping layer 20 and requiring solder joints to be set on the first doping layer 20, and no specific limitation is given here.

[0048] In some embodiments, the polarity of the second doping layer 30 is opposite to that of the first doping layer 20 , and the roughness of the surface 301 where the second doping layer 30 contacts the first passivation film layer 40 is greater than the roughness of the surface 202 where the first doping layer 20 contacts the first passivation film layer 40 .

[0049] In this way, the roughness of the surface 301 where the second doping layer 30 contacts the first passivation film layer 40 is greater than the roughness of the surface 202 where the first doping layer 20 contacts the first passivation film layer 40, so that the bonding tension between the first passivation film layer 40 and the second doping layer 30 is greater than the bonding tension between the first passivation film layer 40 and the first doping layer 20, which can effectively increase the welding tension of the first solder joint 50 during welding, thereby effectively preventing the first solder joint 50 from detaching during welding.

[0050] Specifically, the first doped layer 20 and the second doped layer 30 can be a P-type doped layer and an N-type doped layer, respectively, as long as their polarities are opposite. For example, in some embodiments, the first doped layer 20 can be a P-type polycrystalline silicon layer, a P-type amorphous silicon layer, or a P-type microcrystalline silicon layer, without limitation. Similarly, the second doped layer 30 can be an N-type polycrystalline silicon layer, an N-type amorphous silicon layer, or an N-type microcrystalline silicon layer, without limitation.

[0051] In some embodiments, the polarity of the second doping layer 30 is opposite to that of the first doping layer 20 , and the first doping layer 20 is a P-type doping layer, while the second doping layer 30 is an N-type doping layer.

[0052] In some embodiments, a tunneling oxide layer or an intrinsic amorphous silicon layer (not shown) may be provided between the first doped layer 20 and the silicon substrate 10. Specifically, when the solar cell is a Topcon solar cell or a back-contact solar cell, a tunneling oxide layer may be provided between the first doped layer 20 and the silicon substrate 10. When the solar cell is an HJT solar cell, an intrinsic amorphous silicon layer may be provided between the first doped layer 20 and the silicon substrate 10.

[0053] 3 , in some embodiments, the first predetermined region 201 is a portion of the first doped layer 20 facing away from the surface of the silicon substrate 10 , and the second doped layer 30 is stacked on the first predetermined region 201 and is located above the first doped layer 20 .

[0054] Specifically, as shown in FIG3 , the first predetermined area 201 is a portion of the surface of the first doping layer 20 away from the silicon substrate 10, which is substantially a planar area. In this case, the second doping layer 30 is directly stacked on the first doping layer 20 and is located on the second doping layer 30.

[0055] Referring to FIG. 4 , in some other embodiments, the first predetermined region 201 may be a first embedding groove 210 recessed on the first doping layer 20 , and the second doping layer 30 is stacked in the first embedding groove 210 . In the thickness direction of the solar cell 100 , the first welding point 50 and the second doping layer 30 at least partially overlap.

[0056] It can be understood that in the present application, the second doping layer 30 is located in the first embedding groove 210, and all parts of the first doping layer 30 can be completely contained in the first embedding groove 210, or part of the first doping layer 30 can extend out of the first embedding groove 210 in the thickness direction. There is no specific limitation here.

[0057] In some embodiments, the depth of the first embedding trench 210 may be 5 nm-400 nm.

[0058] In this way, it is possible to effectively avoid the first embedded groove 210 being too shallow, which would result in the second doped layer 30 being too thin and thus causing poor tensile strength enhancement effect, and it is also possible to avoid the first embedded groove 210 being too deep, which would result in the second doped layer 30 being too thick and thus causing increased costs.

[0059] Specifically, the depth of the first embedded groove 210 may be 5nm, 10nm, 20nm, 30nm, 40nm, 50nm, 60nm, 70nm, 80nm, 90nm, 100nm, 150nm, 200nm, 250nm, 300nm, 350nm, 400nm or any value between 5nm and 400nm, and is not limited here.

[0060] 5 and 6 , in some embodiments, the solar cell 100 may further include a first isolation layer 60 . The first isolation layer 60 may be stacked between the first doping layer 20 and the second doping layer 30 to separate the first doping layer 20 from the second doping layer 30 .

[0061] In this way, the second doping layer 30 can be separated from the first doping layer 20 by the first isolation layer 60 to avoid direct contact between the two, while also ensuring the passivation effect of the first doping layer 20 .

[0062] Specifically, in such a case, as shown in FIG5 , in some embodiments, the first isolation layer 60 may be directly stacked on the surface of the first doping layer 20 and cover the first doping layer 20, and the second doping layer 30 may cover the first isolation layer 60. As shown in FIG6 , in some embodiments, the first isolation layer 60 may be stacked on the inner wall of the first embedded groove 210, that is, the first isolation layer 60 is disposed on the inner wall of the first embedded groove 210, and the second doping layer 30 may be stacked and covered on the first isolation layer 60.

[0063] Of course, it is understandable that in some embodiments, it is not necessary to set the first isolation layer 60 to separate the first doped layer 20 and the second doped layer 30. It is only necessary to set the metal grid line in contact with the first doped layer 20 in the solar cell 100 to not contact the second doped layer 30. No specific limitation is made here.

[0064] In some embodiments, the thickness of the first isolation layer 60 may be greater than 2 nm. This can avoid a significant increase in process difficulty caused by the thickness of the first isolation layer 60 being too small.

[0065] Furthermore, in some embodiments, the first isolation layer 60 may include at least one of a silicon oxide film layer, a silicon nitride film layer, an aluminum oxide film layer, a silicon oxynitride film layer, a silicon carbide film layer, and an intrinsic amorphous silicon film layer.

[0066] Specifically, in such an embodiment, the first isolation layer 60 may or may not have a tunneling function, and may be an insulating layer or a non-insulating layer. There is no specific limitation here, and the specific film layer may be selected according to different types of battery cells.

[0067] For example, when the cell is a Topcon solar cell and a back contact cell, the first isolation layer 60 may be at least one of a silicon oxide film layer, a silicon nitride film layer, an aluminum oxide film layer, a silicon oxynitride film layer, and a silicon carbide film layer. The first isolation layer 60 may or may not have a tunneling function.

[0068] When the cell is a HJT solar cell, the first isolation layer 60 may be an intrinsic amorphous silicon layer. It is understood that the specific selection of the first isolation layer 60 is merely an example description here, and it is not to be construed as limiting the present application.

[0069] As shown in Figures 3-6, in some embodiments, the orthographic projection area of ​​the first predetermined region 201 on the silicon substrate 10 is greater than or equal to the orthographic projection area of ​​the first solder joint 50 on the silicon substrate 10. The orthographic projection of the first solder joint 50 on the first doped layer 20 is completely located within the first predetermined region 201. That is, in the thickness direction of the solar cell 100, the first solder joint 50 is completely located above the second doped layer 30. When the first predetermined region 201 is the first embedding groove 210, the orthographic projection of the first solder joint 50 on the first doped layer 20 is completely located within the first embedding groove 210.

[0070] In this way, the first solder joint 50 is completely located in the first preset area 201, and the entire bottom of the first solder joint 50 has the second doping layer, which can maximize the welding tension at the first solder joint 50, thereby ensuring the reliability of welding.

[0071] Specifically, in such an embodiment, the area of ​​the first preset region 201 may preferably be just equal to the orthographic projection area of ​​the first welding point 50 or slightly larger than the orthographic projection area of ​​the first welding point 50 .

[0072] Of course, in some embodiments, the orthographic projection area of ​​the first solder joint 50 on the first doping layer 20 may also be larger than the orthographic projection area of ​​the second doping layer 30 on the first doping layer 20 (that is, the area of ​​the first preset area 201). For example, a single first solder joint 50 may correspond to multiple second doping layers 30. In such a case, the first solder joint 50 may completely cover the second doping layer 30. In such a case, the ratio of the overlapping area of ​​the second doping layer 30 and the first solder joint 50 to the total area of ​​the first solder joint 50 may be greater than 20% to avoid too small a welding tension.

[0073] In addition, in some embodiments, the first solder joint 50 can be bonded above the first passivation film layer 40, or partially embedded in the first passivation film layer 40, or at least partially penetrate the first passivation film layer 40 to contact the second doping layer 30. When the first solder joint 50 contacts the second doping layer 30, the first doping layer 20 and the second doping layer 30 can be isolated by setting a first isolation layer 60. No specific restrictions are set here.

[0074] In some embodiments, the thickness of the second doping layer 30 may be 5 nm-400 nm.

[0075] In this way, it is possible to effectively avoid the second doping layer 30 being too thin to cause poor tensile reinforcement effect, the second doping layer 30 being too thin to cause increased process difficulty, and the second doping layer 30 being too thick to cause increased cost.

[0076] Specifically, the thickness of the second doping layer 30 may be 5nm, 10nm, 20nm, 30nm, 40nm, 50nm, 60nm, 70nm, 80nm, 90nm, 100nm, 150nm, 200nm, 250nm, 300nm, 350nm, 400nm or any value between 5nm and 400nm, and is not limited here.

[0077] In some embodiments, the first passivation film layer 40 may include at least one of a silicon nitride film layer, an aluminum oxide film layer, a silicon oxynitride film layer, an intrinsic amorphous silicon film layer, and a TCO film layer.

[0078] Specifically, in such an embodiment, the type of the first passivation film layer 40 can also be selected according to different types of cell wafers. For example, when the cell is a Topcon solar cell and a back contact cell, the first passivation film layer 40 can be at least one of a silicon oxide film layer, a silicon nitride film layer, an aluminum oxide film layer, a silicon oxynitride film layer, and a silicon carbide film layer.

[0079] When the cell is an HJT solar cell, the first passivation film layer 40 can be a TCO film layer, which is not specifically limited here. It is understood that this is merely an example of the specific selection of the first passivation film layer 40, and it is not to be understood as a limitation of the present application.

[0080] 7 to 13 , in some embodiments, the solar cell 100 may further include a third doping layer 70 , a second passivation film 80 , and a plurality of second solder joints 90 . The polarity of the third doping layer 70 is opposite to that of the first doping layer 20 .

[0081] As shown in Figures 8 to 11, in some embodiments, the first doping layer 20 may be stacked on the first surface 11, the third doping layer 70 may be stacked on the second surface 12, the second passivation film layer 80 is stacked on the third doping layer 70, and the second solder joint 90 is provided on the second passivation film layer 80. In this case, the solar cell 100 is a double-sided solar cell, such as a Topcon solar cell, an HJT solar cell, etc.

[0082] Similarly, in the present application, the second passivation film layer 80 may also include at least one of a silicon nitride film layer, an aluminum oxide film layer, a silicon oxynitride film layer, an intrinsic amorphous silicon film layer, and a TCO film layer.

[0083] As shown in Figures 12-16, in some embodiments, the first doping layer 20 and the third doping layer 70 may also be stacked on the first surface 11, the first passivation film layer 40 may be stacked on the first doping layer 20, the second doping layer 30, and the third doping layer 70, the second solder joint 90 may also be disposed on the first passivation film layer 40, and the second passivation film layer 80 may be stacked on the second surface 12. In this case, the solar cell 100 is a back-contact cell, the first surface 11 is the back side of the cell, and the second surface 12 is the front side of the cell.

[0084] In the embodiment of the present application, in the solar cell 100, the second doped layer 30 can be obtained by partially removing the wrap-around layer formed on the first doped layer 20 during the process of forming the third doped layer 70 described above, and the roughness of the second doped layer 30 can be controlled by controlling the temperature and time of deposition or by etching. Of course, in some embodiments, the second doped layer 30 can also be directly obtained by deposition. Similarly, the roughness of the second doped layer 30 can also be controlled by controlling the temperature and time of deposition or by etching, and the specific details are not limited here.

[0085] It can be understood that when the solar cell 100 is a bifacial solar cell, a plurality of first auxiliary grids (not shown) are provided on the first passivation film layer 40, and the first auxiliary grids penetrate the first passivation film layer 40 and contact the first doped layer 20, and a plurality of second auxiliary grids (not shown) are also provided on the second passivation film layer 80, and the second auxiliary grids penetrate the second passivation film layer 80 and contact the third doped layer 70. In the bifacial solar cell, a first main grid (not shown) that crosses and contacts the first auxiliary grid and a second main grid (not shown) that crosses and contacts the second auxiliary grid are also provided. The first welding point 50 can be provided on the first main grid, which can be located on the first passivation film layer 40 or partially embedded in the first passivation film layer 40 or penetrate the first passivation film layer 40 and contact the second doping layer 30 below the first passivation film layer 40. The first welding point 50 is used for welding with the welding ribbon. Similarly, the second welding point 90 can be provided on the second main grid, which can be located on the second passivation film layer 80 or partially embedded in the second passivation film layer 80 or penetrate the second passivation film layer 80. The second welding point 90 is also used for welding with the welding ribbon.

[0086] When the solar cell 100 is a back-contact cell, the first passivation film layer 40 is provided with a third sub-grid (not shown) and a fourth sub-grid (not shown). The third sub-grid penetrates the first passivation film layer 40 and contacts the first doped layer 20 , and the fourth sub-grid penetrates the first passivation film layer 40 and contacts the third doped layer 70 .

[0087] When the solar cell 100 is a back contact cell, it can be divided into the following two cases:

[0088] The first type: As shown in Figure 12, in some embodiments, on the first surface 11, a plurality of first doped layers 20 and a plurality of third doped layers 70 may be arranged alternately along the first direction, and both the first doped layers 20 and the third doped layers 70 extend along the second direction, intersecting the first direction, which may be the longitudinal direction and the transverse direction of the solar cell 100, respectively. As shown in Figure 12, in this embodiment, the first doped layers 20 and the third doped layers 70 are continuous doped layers along the second direction, and are arranged alternately along the first direction.

[0089] In a back-contact battery, a main grid may be set or not. When a main grid is set, it includes several third main grids (not shown in the figure) and several fourth main grids (not shown in the figure). Several third main grids and several fourth main grids are alternately arranged along the second direction. The third auxiliary grid is connected to the third main grid and disconnected at the fourth main grid. The fourth auxiliary grid is connected to the fourth main grid and disconnected at the third main grid. The first welding point 50 is set at the third main grid and connected to the third main grid. The second welding point 90 is set at the fourth main grid and connected to the fourth main grid. Several first welding points 50 can be set along the extension direction of the third main grid, and several second welding points 90 can be set along the extension direction of the fourth main grid.

[0090] When no main grid is provided, the first welding point 50 and the second welding point 90 can be directly provided in the area covered by the welding strip of the battery. For example, the first welding point 50 can be provided at the disconnection point of the third auxiliary grid, and the second welding point 90 can be provided at the disconnection point of the fourth auxiliary grid. In this way, the welding points can be directly connected to the welding strip in the absence of a main grid. It can be understood that in such a case, the welding strip welded to the first welding point 50 can be electrically connected to all third auxiliary grids, and the welding strip welded to the second welding point 90 can be electrically connected to all fourth auxiliary grids. Of course, in some embodiments, the third and fourth auxiliary grids can also be provided without disconnection, but can be isolated by providing insulating glue at the locations of the main grid or welding strips of opposite polarity. The specific details are not limited here.

[0091] Second type: As shown in FIG17 , in some embodiments, the first doping layer 20 may include a plurality of first sub-doping layers 21 and a second sub-doping layer 22, and the third doping layer 70 may include a plurality of third sub-doping layers 71 and a plurality of fourth sub-doping layers 72. The plurality of first sub-doping layers 21 and the plurality of third sub-doping layers 71 are alternately arranged in sequence along the first direction and spaced apart on the first surface 11 and extend along the second direction. The plurality of second sub-doping layers 22 and the plurality of fourth sub-doping layers 72 are alternately arranged in sequence along the second direction and spaced apart on the first surface 11 and extend along the first direction. The first sub-doping layer 21 is disconnected at the fourth sub-doping layer 72 and contacts the second sub-doping layer 22, and the third sub-doping layer 71 is disconnected at the second sub-doping layer 22 and contacts the fourth sub-doping layer 72. The second sub-doping layer 22 has a plurality of first predetermined regions 201, which are spaced apart along the second direction. The number of first solder joints 50 may correspond to the number of first predetermined regions 201. In this case, the first solder joint 50 may be disposed on the second sub-doped layer 22 , and the second solder joint 90 may be disposed on the fourth sub-doped layer 72 .

[0092] Specifically, it is easy to understand that the first sub-doping layer 21 and the second sub-doping layer 22 together constitute the comb-tooth-shaped first doping layer 20, and the third sub-doping layer 71 and the fourth sub-doping layer 72 together constitute the comb-tooth-shaped third doping layer 70. The first sub-doping layer 21 and the second sub-doping layer 22 can be formed by the same process, and the third doping layer 71 and the fourth sub-doping layer 72 can be formed by the same process.

[0093] Furthermore, in such an embodiment, in the first direction, the length of the first solder joint 50 is greater than the length of the second doping layer 30, and the ratio of the length of the first solder joint 50 above the second doping layer 30 to the total length of the first solder joint 50 is greater than or equal to 20%.

[0094] In this way, when the length of the first solder joint 50 in the first direction is relatively large, setting the ratio of the length of the first solder joint 50 above the second doping layer 30 (i.e., the length of the orthographic projection of the first solder joint 50 in the thickness direction overlapping with the second doping layer 30) to the total length of the first solder joint 50 to be greater than or equal to 20% can effectively ensure the welding tension of the first solder joint 50 and avoid insufficient welding tension.

[0095] Preferably, in such an embodiment, in order to ensure the welding tension of the first welding spot 50 , the ratio of the length of the first welding spot 50 located above the second doping layer 30 to the total length of the first welding spot 50 is greater than or equal to 50%.

[0096] In some embodiments, the ratio of the orthographic projection area of ​​the second doped layer 30 on the second sub-doped layer 22 to the area of ​​the second sub-doped layer 22 is less than 50%. This can prevent the second doped layer 30 from being too large in area, which would cause the second doped layer 30 to be more likely to recombine with the second sub-doped layer 22 and result in large recombination losses.

[0097] Specifically, in such an embodiment, "the ratio of the area of ​​the orthographic projection of the second doping layer 30 on the second sub-doping layer 22 to the area of ​​the second sub-doping layer 22 is less than 50%" can be that the ratio of the area of ​​all second doping layers 30 on a single second sub-doping layer 22 to the area of ​​a single second sub-doping layer 22 is less than 50%, or it can be that the ratio of the sum of the areas of all second doping layers 30 on the entire back contact battery to the sum of the areas of all second sub-doping layers 22 is less than 50%. There is no specific limitation here, and the first one is preferred.

[0098] Furthermore, as shown in FIG. 17 , in such an embodiment, in the first direction, the distance between two adjacent first welding points 50 may be 3 mm to 40 mm.

[0099] In this way, by setting the spacing between two adjacent first solder joints 50 within this reasonable range, the first solder joints 50 can be basically within a reasonable spacing, so that there can be enough first solder joints 50 on the same second sub-doping layer 22, thereby avoiding the occurrence of cold solder joints when soldering the solder strips and ensuring the reliability of soldering.

[0100] Specifically, in such an embodiment, the spacing between two adjacent first welding points 50 may be, for example, 3mm, 4mm, 5mm, 6mm, 7mm, 8mm, 9mm, 10mm, 15mm, 20mm, 25mm, 30mm, 35mm, 40mm or any value between 3mm-40mm, and is not limited here.

[0101] In some embodiments, the third doping layer 70 may have several second preset areas 701 , and the solar cell 100 may further include a fourth doping layer 110 . The fourth doping layer 110 is stacked and disposed in the second preset areas 701 , and the several fourth doping layers 110 are disposed at intervals.

[0102] As shown in Figures 9 and 11, when the third doped layer 70 is stacked on the second surface 12, the second passivation film layer 80 covers the third doped layer 70 and the fourth doped layer 110, and the orthographic projection of the second solder joint 90 on the third doped layer 70 and the orthographic projection of the fourth doped layer 110 on the third doped layer 70 at least partially overlap (that is, in the thickness direction of the solar cell 100, the second solder joint 90 and the fourth doped layer 110 at least partially overlap).

[0103] As shown in Figures 14 and 16, when the third doped layer 70 is stacked on the first surface 11, the first passivation film layer 40 covers the first doped layer 20, the second doped layer 30, the third doped layer 70 and the fourth doped layer 110, and the orthographic projection of the second solder joint 90 on the third doped layer 70 and the orthographic projection of the fourth doped layer 110 on the third doped layer 70 at least partially overlap (in the thickness direction of the solar cell 100, the second solder joint 90 and the fourth doped layer 110 at least partially overlap).

[0104] In this way, while increasing the tensile force of the first welding point 50 during welding, the tensile force of the second welding point 90 during welding can also be effectively increased, effectively preventing the second welding point 90 from detaching during welding.

[0105] In some embodiments, the fourth doping layer 110 has an opposite polarity to the third doping layer 70 ;

[0106] In the case where the third doping layer 70 is stacked on the second surface 12 , the roughness of the surface 111 of the fourth doping layer 110 in contact with the second passivation film layer 80 is greater than the roughness of the surface 702 of the third doping layer 70 in contact with the second passivation film layer 80 ;

[0107] When the third doping layer 70 is stacked on the first surface 11 , the roughness of the surface 111 of the fourth doping layer 110 in contact with the first passivation film layer 40 is greater than the roughness of the surface 702 of the third doping layer 70 in contact with the first passivation film layer 40 .

[0108] In this way, by setting the roughness, the tensile force of the second welding point 90 during welding can be further increased.

[0109] 14 , in some embodiments, the second predetermined region 701 is a portion of the third doped layer 70 facing away from the surface of the silicon substrate 10 , and the fourth doped layer 110 is stacked on the second predetermined region 701 and is located above the third doped layer 70 .

[0110] Specifically, as shown in FIG14 , the second predetermined area 701 is a portion of the surface of the third doping layer 70 away from the silicon substrate 10, which is substantially a planar area. In this case, the fourth doping layer 110 is directly stacked on the third doping layer 70 and is located on the fourth doping layer 110.

[0111] Referring to FIG. 16 , in some other embodiments, the second predetermined region 701 may be a second embedding groove 701 recessed on the third doping layer 70 , and the fourth doping layer 110 is stacked in the second embedding groove 701 . In the thickness direction of the solar cell 100 , the first solder joint 50 and the fourth doping layer 110 at least partially overlap.

[0112] It can be understood that in the present application, the fourth doping layer 110 is located in the second embedding groove 701, and all parts of the first doping layer 30 can be completely contained in the second embedding groove 701, or part of the first doping layer 30 can extend out of the second embedding groove 701 in the thickness direction. There is no specific limitation here.

[0113] In some embodiments, the depth of the second embedding trench 701 may be 5 nm-400 nm.

[0114] In this way, it is possible to effectively avoid the second embedded groove 701 being too shallow, which would result in the fourth doped layer 110 being too thin and thus leading to poor tensile strength enhancement effect, and it is also possible to avoid the second embedded groove 701 being too deep, which would result in the fourth doped layer 110 being too thick and thus leading to increased costs.

[0115] Specifically, the depth of the second embedded groove 701 can be 5nm, 10nm, 20nm, 30nm, 40nm, 50nm, 60nm, 70nm, 80nm, 90nm, 100nm, 150nm, 200nm, 250nm, 300nm, 350nm, 400nm or any value between 5nm and 400nm, and is not limited here.

[0116] Referring to FIG. 14 and FIG. 16 , in some embodiments, the solar cell 100 may further include a second isolation layer 120 . The second isolation layer 120 may be stacked between the third doping layer 70 and the fourth doping layer 110 to separate the third doping layer 70 from the fourth doping layer 110 .

[0117] In this way, the fourth doping layer 110 can be separated from the third doping layer 70 by the second isolation layer 120 to avoid direct contact between the two, while also ensuring the passivation effect of the third doping layer 70 .

[0118] Specifically, in such a case, as shown in FIG14 , in some embodiments, the second isolation layer 120 may be directly stacked on the surface of the third doped layer 70 and cover the third doped layer 70, and the fourth doped layer 110 may cover the second isolation layer 120. As shown in FIG16 , in some embodiments, the second isolation layer 120 may be stacked on the inner wall of the second embedded groove 701, that is, the second isolation layer 120 is disposed on the inner wall of the second embedded groove 701, and the fourth doped layer 110 may be stacked and covered on the second isolation layer 120.

[0119] Of course, it is understandable that, in some embodiments, it is not necessary to provide the second isolation layer 120 to separate the third doping layer 70 and the fourth doping layer 110 , and this is not specifically limited here.

[0120] In some embodiments, the thickness of the second isolation layer 120 may be greater than 2 nm. This can avoid significantly increasing the difficulty of the process due to the thickness of the second isolation layer 120 being too small.

[0121] Furthermore, in some embodiments, the second isolation layer 120 may include at least one of a silicon oxide film layer, a silicon nitride film layer, an aluminum oxide film layer, a silicon oxynitride film layer, a silicon carbide film layer, and an intrinsic amorphous silicon film layer.

[0122] Specifically, in such an embodiment, the second isolation layer 120 may or may not have a tunneling function. It may be an insulating layer or a non-insulating layer. There is no specific limitation here. The specific film layer can be selected according to different types of battery cells.

[0123] For example, when the cell is a Topcon solar cell and a back contact cell, the second isolation layer 120 may be at least one of a silicon oxide film layer, a silicon nitride film layer, an aluminum oxide film layer, a silicon oxynitride film layer, and a silicon carbide film layer, and the second isolation layer 120 may or may not have a tunneling function.

[0124] When the cell is a HJT solar cell, the second isolation layer 120 may be an intrinsic amorphous silicon layer. It is understood that the specific selection of the second isolation layer 120 is merely an example, and should not be construed as limiting the present application.

[0125] In some embodiments, the orthographic projection of the second solder joint 90 on the third doped layer 70 is completely located within the second predetermined area 701 , that is, in the thickness direction of the solar cell 100 , the second solder joint 90 is completely located above the fourth doped layer 110 .

[0126] In this way, the second solder joint 90 is completely located in the second preset area 701 , and the entire bottom of the second solder joint 90 has the fourth doping layer 110 , which can maximize the welding tension at the second solder joint 90 and ensure the reliability of welding.

[0127] Specifically, in such an embodiment, the area of ​​the second preset region 701 may preferably be just equal to the orthographic projection area of ​​the second welding point 90 or slightly larger than the orthographic projection area of ​​the second welding point 90 .

[0128] Of course, in some embodiments, the orthographic projection area of ​​the second solder joint 90 on the third doping layer 70 may also be larger than the orthographic projection area of ​​the fourth doping layer 110 on the third doping layer 70 (that is, the area of ​​the second preset area 701). For example, a single second solder joint 90 may correspond to multiple fourth doping layers 110. In such a case, the second solder joint 90 may completely cover the fourth doping layer 110. In such a case, the ratio of the overlapping area of ​​the fourth doping layer 110 and the second solder joint 90 to the total area of ​​the second solder joint 90 may be greater than 20% to avoid excessively low welding tension.

[0129] In some embodiments, the fourth doping layer 110 may have a thickness of 5 nm-400 nm.

[0130] In this way, it is possible to effectively avoid the fourth doping layer 110 being too thin, which would result in poor tensile reinforcement effect, the fourth doping layer being too thin, which would result in increased process difficulty, and the fourth doping layer being too thick, which would result in increased cost.

[0131] Specifically, the thickness of the fourth doping layer 110 may be 5nm, 10nm, 20nm, 30nm, 40nm, 50nm, 60nm, 70nm, 80nm, 90nm, 100nm, 150nm, 200nm, 250nm, 300nm, 350nm, 400nm or any value between 5nm-400nm, and is not limited here.

[0132] Furthermore, as shown in FIG17 , in the case where the third doping layer 70 is disposed on the first surface 11 and the first doping layer 20 includes a plurality of first sub-doping layers 21 and a second sub-doping layer 22, and the third doping layer 70 includes a plurality of third sub-doping layers 71 and a plurality of fourth sub-doping layers 72, the second sub-doping layer 22 has a plurality of first preset regions 201, the plurality of first preset regions 201 being spaced apart along the second direction, and the number of first solder joints 50 corresponds to the number of first preset regions 201. The fourth sub-doping layer 72 has a plurality of second preset regions 701, the plurality of second preset regions 701 being spaced apart along the first direction, and the number of pairs of second solder joints 90 corresponds to the number of second preset regions 701. That is, in this case, the fourth doping layer 110 is stacked on the second preset regions 701 of the fourth sub-doping layer 72.

[0133] As shown in Figure 17, in such an embodiment, in the first direction, the length of the second solder joint 90 may be greater than the length of the fourth doping layer 110, and the ratio of the length of the second solder joint 90 located above the fourth doping layer 110 to the total length of the second solder joint 90 is greater than or equal to 20%.

[0134] In this way, when the length of the second solder joint 90 in the first direction is relatively large, setting the ratio of the length of the second solder joint 90 above the fourth doping layer 110 (i.e., the length of the orthographic projection of the second solder joint 90 in the thickness direction overlapping with the fourth doping layer 110) to the total length of the second solder joint 90 to be greater than or equal to 20% can effectively ensure the welding tension of the second solder joint 90 and avoid insufficient welding tension.

[0135] Preferably, in such an embodiment, in order to ensure the welding tension of the second welding spot 90 , the ratio of the length of the second welding spot 90 located above the fourth doping layer 110 to the total length of the second welding spot 90 is greater than or equal to 50%.

[0136] In some embodiments, the ratio of the orthographic projection area of ​​the fourth doped layer 110 on the fourth sub-doped layer 72 to the area of ​​the fourth sub-doped layer 72 is less than 50%. This can prevent the fourth doped layer 110 from occupying too large an area, which would cause the fourth doped layer 110 to be more likely to recombine with the fourth sub-doped layer 72 and result in large recombination losses.

[0137] Specifically, in such an embodiment, "the ratio of the area of ​​the orthographic projection of the fourth doping layer 110 on the fourth sub-doping layer 72 to the area of ​​the fourth sub-doping layer 72 is less than 50%" can be that the ratio of the area of ​​all fourth doping layers 110 on a single fourth sub-doping layer 72 to the single fourth sub-doping layer 72 is less than 50%, or it can be that the ratio of the sum of the areas of all fourth doping layers 110 on the entire back contact battery to the sum of the areas of all fourth sub-doping layers 72 is less than 50%. There is no specific limitation here, and the first one is preferred.

[0138] Furthermore, as shown in FIG. 17 , in such an embodiment, in the first direction, the distance between two adjacent second welding points 90 may be 3 mm to 40 mm.

[0139] In this way, by setting the spacing between two adjacent second solder joints 90 within this reasonable range, the second solder joints 90 can be basically within a reasonable spacing, so that there can be enough second solder joints 90 on the same fourth sub-doping layer 72, thereby avoiding the occurrence of cold solder joints when soldering the solder strips and ensuring the reliability of soldering.

[0140] Specifically, in such an embodiment, the spacing between two adjacent second welding points 90 may be, for example, 3mm, 4mm, 5mm, 6mm, 7mm, 8mm, 9mm, 10mm, 15mm, 20mm, 25mm, 30mm, 35mm, 40mm or any value between 3mm-40mm, and is not limited here.

[0141] Throughout this specification, reference to terms such as "one embodiment," "some embodiments," "examples," "specific examples," or "some examples" means that a specific feature, structure, material, or characteristic described in conjunction with the embodiment or example is included in at least one embodiment or example of the present application. In this specification, schematic representations 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 any one or more embodiments or examples.

[0142] Although the embodiments of the present application have been shown and described, those skilled in the art will appreciate that various changes, modifications, substitutions, and variations may be made to the embodiments without departing from the principles and intent of the present application, and that the scope of the present application is defined by the claims and their equivalents.

Claims

1. A solar cell, characterized in that: include: A silicon substrate having a first surface and a second surface opposite to each other; A first doping layer stacked on the first surface, wherein the first doping layer has a plurality of first preset regions; A second doping layer is arranged at the first preset area, and a plurality of the second doping layers are arranged at intervals; A first passivation film layer, wherein the first passivation film layer is stacked on the second doping layer and the first doping layer; and A plurality of first welding points, wherein the first welding points are arranged on the first passivation film layer, and an orthographic projection of the first welding points on the first doping layer at least partially overlaps with an orthographic projection of the second doping layer on the first doping layer.

2. The solar cell according to claim 1, characterized in that: The polarity of the second doping layer is opposite to that of the first doping layer, and the roughness of a surface of the second doping layer in contact with the first passivation film layer is greater than the roughness of a surface of the first doping layer in contact with the first passivation film layer.

3. The solar cell according to claim 1, characterized in that: The first doping layer is a P-type doping layer, the second doping layer is an N-type doping layer, and the first welding point is at least partially located above the second doping layer.

4. The solar cell according to claim 1, characterized in that: The first preset region is a portion of the surface of the first doped layer away from the silicon substrate, and the second doped layer is stacked on the first preset region and is located above the first doped layer; or The first preset area is a first embedding groove formed concavely on the first doping layer, the second doping layer is arranged in the first embedding groove, and in the thickness direction of the solar cell sheet, the first welding point and the second doping layer at least partially overlap.

5. The solar cell according to claim 4, characterized in that: When the first preset area is the first embedded groove, the depth of the first embedded groove is 5nm-400nm.

6. The solar cell according to claim 4, characterized in that: The solar cell further includes a first isolation layer, which is stacked between the first doping layer and the second doping layer to separate the first doping layer from the second doping layer.

7. The solar cell according to claim 6, characterized in that: The thickness of the first isolation layer is greater than 2 nm.

8. The solar cell according to claim 6, characterized in that: The first isolation layer includes at least one of a silicon oxide film layer, a silicon nitride film layer, an aluminum oxide film layer, a silicon oxynitride film layer, a silicon carbide film layer and an intrinsic amorphous silicon film layer.

9. The solar cell according to claim 1, characterized in that: The orthographic projection area of ​​the first preset region on the silicon substrate is greater than or equal to the orthographic projection area of ​​the first welding point on the silicon substrate, and the orthographic projection of the first welding point on the first doping layer is completely located in the first preset region.

10. The solar cell according to claim 1, characterized in that: The thickness of the second doping layer is 5nm-400nm.

11. The solar cell according to claim 1, characterized in that: The first passivation film layer includes at least one of a silicon nitride film layer, an aluminum oxide film layer, a silicon oxynitride film layer, an intrinsic amorphous silicon film layer, and a TCO film layer.

12. The solar cell according to any one of claims 1 to 11, characterized in that: The solar cell further comprises a third doping layer, a second passivation film layer and a plurality of second solder joints, wherein the polarity of the third doping layer is opposite to that of the first doping layer; wherein the first doped layer is stacked on the first surface, the third doped layer is stacked on the second surface, the second passivation film layer is stacked on the third doped layer, and the second solder joint is arranged on the second passivation film layer; or The first doping layer and the third doping layer are both stacked on the first surface, the first passivation film layer is stacked on the first doping layer, the second doping layer and the third doping layer, the second welding point is also arranged on the first passivation film layer, and the second passivation film layer is stacked on the second surface.

13. The solar cell according to claim 12, characterized in that: In the case where the third doping layer is stacked on the first surface, on the first surface, a plurality of the first doping layers and a plurality of the third doping layers are alternately arranged in sequence along a first direction, and both the first doping layers and the third doping layers extend along a second direction, and the second direction intersects with the first direction.

14. The solar cell according to claim 12, characterized in that: In the case where the third doping layer is stacked and arranged on the first surface, the first doping layer includes a plurality of first sub-doping layers and a second sub-doping layer, and the third doping layer includes a plurality of third sub-doping layers and a plurality of fourth sub-doping layers; A plurality of the first sub-doping layers and a plurality of the third sub-doping layers are alternately arranged in sequence along a first direction and are disposed on the first surface at intervals and extend along a second direction, wherein the second direction intersects the first direction; A plurality of the second sub-doping layers and a plurality of the fourth sub-doping layers are arranged alternately and spaced in sequence along the second direction on the first surface and extend along the first direction, the first sub-doping layer is disconnected at the fourth sub-doping layer and contacts the second sub-doping layer, and the third sub-doping layer is disconnected at the second sub-doping layer and contacts the fourth sub-doping layer; The second sub-doping layer has a plurality of the first preset regions, and the plurality of the first preset regions are arranged at intervals along the second direction.

15. The solar cell according to claim 14, characterized in that: In the first direction, the length of the first solder joint is greater than the length of the second doping layer, and a ratio of a length of the first solder joint located above the second doping layer to a total length of the first solder joint is greater than or equal to 20%.

16. The solar cell according to claim 14, characterized in that: In the first direction, a ratio of a length of the first solder joint located above the second doping layer to a total length of the first solder joint is greater than or equal to 50%.

17. The solar cell according to claim 14, characterized in that: A ratio of an orthographic projection area of ​​the second doping layer on the second sub-doping layer to an area of ​​the second sub-doping layer is less than or equal to 50%.

18. The solar cell according to claim 14, characterized in that: In the first direction, the distance between two adjacent first welding points is 3 mm-40 mm.

19. The solar cell according to claim 12, characterized in that: The third doping layer has a plurality of second preset regions, the solar cell further comprises a fourth doping layer, the fourth doping layer is stacked and arranged at the second preset region, the plurality of fourth doping layers are arranged at intervals, and the fourth doping layer has a polarity opposite to that of the third doping layer; In the case where the third doped layer is stacked on the second surface, the second passivation film layer covers the third doped layer and the fourth doped layer, and the orthographic projection of the second welding point on the third doped layer at least partially overlaps with the orthographic projection of the fourth doped layer on the third doped layer; When the third doped layer is stacked on the first surface, the first passivation film layer covers the first doped layer, the second doped layer, the third doped layer and the fourth doped layer, and the orthographic projection of the second welding point on the third doped layer at least partially overlaps with the orthographic projection of the fourth doped layer on the third doped layer.

20. The solar cell according to claim 19, characterized in that: The fourth doping layer has a polarity opposite to that of the third doping layer; In the case where the third doped layer is stacked on the second surface, the roughness of the surface of the fourth doped layer in contact with the second passivation film layer is greater than the roughness of the surface of the third doped layer in contact with the second passivation film layer; In the case where the third doping layer is stacked on the first surface, the roughness of a surface of the fourth doping layer in contact with the first passivation film layer is greater than the roughness of a surface of the third doping layer in contact with the first passivation film layer.

21. The solar cell according to claim 19, characterized in that: The second preset region is a portion of the surface of the third doped layer away from the silicon substrate, and the fourth doped layer is stacked on the second preset region and is located above the third doped layer; or The second preset area is a second embedding groove formed concavely on the third doping layer, the fourth doping layer is arranged in the second embedding groove, and in the thickness direction of the solar cell sheet, the first welding point at least partially overlaps with the second doping layer.

22. The solar cell according to claim 21, characterized in that: When the second preset area is the second embedded groove, the depth of the second embedded groove is 5nm-400nm.

23. The solar cell according to claim 19, characterized in that: The solar cell further includes a second isolation layer, which is stacked between the third doping layer and the fourth doping layer to separate the third doping layer from the fourth doping layer.

24. The solar cell according to claim 23, characterized in that: The thickness of the second isolation layer is greater than 2 nm.

25. The solar cell according to claim 23, characterized in that: The second isolation layer includes at least one of a silicon oxide film layer, a silicon nitride film layer, an aluminum oxide film layer, a silicon oxynitride film layer, a silicon carbide film layer and an intrinsic amorphous silicon film layer.

26. The solar cell according to claim 19, characterized in that: The orthographic projection of the second welding point on the third doping layer is completely located within the second preset area.

27. The solar cell according to claim 19, characterized in that: The thickness of the fourth doping layer is 5nm-400nm; and / or The second passivation film layer includes at least one of a silicon nitride film layer, an aluminum oxide film layer, a silicon oxynitride film layer, an intrinsic amorphous silicon film layer, and a TCO film layer.

28. The solar cell according to claim 19, characterized in that: In the case where the third doping layer is stacked and arranged on the first surface, the first doping layer includes a plurality of first sub-doping layers and a second sub-doping layer, and the third doping layer includes a plurality of third sub-doping layers and a plurality of fourth sub-doping layers; A plurality of the first sub-doping layers and a plurality of the third sub-doping layers are alternately arranged in sequence along a first direction and are disposed on the first surface at intervals and extend along a second direction, wherein the second direction intersects the first direction; A plurality of the second sub-doping layers and a plurality of the fourth sub-doping layers are arranged alternately and spaced in sequence along the second direction on the first surface and extend along the first direction, the first sub-doping layer is disconnected at the fourth sub-doping layer and contacts the second sub-doping layer, and the third sub-doping layer is disconnected at the second sub-doping layer and contacts the fourth sub-doping layer; The second sub-doping layer has a plurality of the first preset regions, which are spaced apart along the first direction; the fourth sub-doping layer has a plurality of the second preset regions, which are spaced apart along the first direction.

29. A battery assembly, characterized in that: The invention comprises the solar cell sheets as described in any one of claims 1 to 28.

30. A photovoltaic system, characterized in that: A battery assembly comprising the battery assembly of claim 29.

Images