Back contact cell and photovoltaic module
By dividing the electrode layer into multiple electrode regions in the back-contact solar cell and using staggered grid lines, the leakage path problem was solved, thereby improving the cell's open-circuit voltage and short-circuit current.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- ANHUI SUNSHINE SOLAR TECHNOLOGY CO LTD
- Filing Date
- 2025-05-22
- Publication Date
- 2026-06-26
Smart Images
Figure CN224419196U_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of photovoltaic technology, and in particular to a back-contact solar cell and a photovoltaic module. Background Technology
[0002] The TOPCon Back Contact (TBC) solar cell uses a method of depositing tunneled SiOx and doped polycrystalline silicon on an N-type silicon substrate to prepare the emitter and back surface field, and prepares P-regions and N-regions arranged in an interdigitated pattern on the back of the cell.
[0003] However, existing back-contact solar cells have leakage channels in the P and N regions. The interdigitated arrangement of the P and N regions will cause the leakage channels to affect the entire cell, amplifying the impact of the leakage channels and thus significantly reducing the open-circuit voltage and short-circuit current of the cell. Utility Model Content
[0004] The purpose of this application is to provide a back-contact solar cell and photovoltaic module, thereby reducing the impact of leakage current channels on the entire battery and improving the open-circuit voltage and short-circuit current of the battery.
[0005] To address the aforementioned technical problems, embodiments of this application provide a back-contact solar cell, comprising: a silicon wafer substrate and an electrode layer disposed on the back side of the silicon wafer substrate, the electrode layer comprising a plurality of parallel electrode regions; each electrode region being disposed of a first grid line group and a second grid line group with the opposite polarity to the first grid line group; the first grid line group comprising a first bus grid line extending along a first direction and a first main grid line connected to the first bus grid line, the endpoint of the first main grid line away from the first bus grid line being connected to a first fine grid line; the first fine grid line extending along the first direction, and the first main grid line extending along a second direction... The second direction extends in a direction different from the first direction; the second grid line group includes a second bus grid line extending in the first direction and a second main grid line connected to the second bus grid line, the end of the second main grid line away from the second bus grid line being connected to a second fine grid line; the second fine grid line extends in the first direction, and a plurality of second main grid lines extend in the second direction; the first main grid line and the second main grid line are spaced apart in the first direction and staggered in the second direction, and the first fine grid line and the second fine grid line are spaced apart in the second direction and staggered in the first direction.
[0006] Embodiments of this application also provide a photovoltaic module, including: a panel, a battery string, and a backsheet stacked sequentially; the battery string is composed of multiple back-contact battery cells as described above.
[0007] In some embodiments, the first gate line group includes a plurality of first main gate lines connected to the first bus gate line; the second gate line group includes a plurality of second main gate lines connected to the second bus gate line; the plurality of first main gate lines and the plurality of second main gate lines are arranged at intervals along the first direction and staggered along the second direction.
[0008] In some embodiments, the endpoint of the first main gate line located on the non-edge side, away from the first bus gate line, is connected to the center point of the first fine gate line; the endpoint of the second main gate line located on the non-edge side, away from the second bus gate line, is connected to the center points of two symmetrical second fine gate lines.
[0009] In some embodiments, the endpoint of the first main gate line located on the edge side, away from the first bus gate line, is connected to the endpoint of a first fine gate line; the endpoint of the second main gate line located on the edge side, away from the second bus gate line, is connected to the endpoint of a second fine gate line.
[0010] In some embodiments, the non-endpoint region of the first main gate line located on the non-edge side is also connected to the center point of at least one third fine gate line, the third fine gate line being arranged with the first fine gate line along the second direction;
[0011] In some embodiments, the non-endpoint region of the second main gate line located on the non-edge side is also connected to the center point of at least one fourth fine gate line, the fourth fine gate line and the second fine gate line being arranged along the second direction; the third fine gate line and the fourth fine gate line are arranged at intervals along the second direction and staggered along the first direction.
[0012] In some embodiments, the non-endpoint regions of the first main gate line located in the edge region are also connected to at least one endpoint of the third fine gate line, and the non-endpoint regions of the second main gate line located in the edge region are also connected to at least one endpoint of the fourth fine gate line.
[0013] In some embodiments, the silicon substrate is an N-type silicon wafer or a P-type silicon wafer.
[0014] The technical solution provided in this application has at least the following advantages:
[0015] This application embodiment divides the electrode layer into multiple electrode regions, with each electrode region having its own grid line arrangement. Even if a leakage channel is generated in the isolation region of the back contact solar cell, the leakage channel only affects the corresponding electrode region, not the entire cell, thereby reducing the impact of the leakage channel on the entire cell and improving the cell's open-circuit voltage and short-circuit current. Attached Figure Description
[0016] One or more embodiments are illustrated by way of example with reference numerals in the accompanying drawings. These illustrations do not constitute a limitation on the embodiments. Elements with the same reference numerals in the drawings are denoted as similar elements. Unless otherwise stated, the figures in the drawings are not to be limited by scale.
[0017] Figure 1 This is a schematic diagram of the structure of the back contact battery cell based on relevant technologies;
[0018] Figure 2 This is a schematic diagram of the structure of a back contact battery cell according to an embodiment of this application;
[0019] Figure 3 This is a schematic diagram of the structure of a back contact battery cell according to another embodiment of this application;
[0020] Figure 4 This is a schematic diagram of the structure of a photovoltaic module according to an embodiment of this application;
[0021] Figure 5 This is a schematic diagram of the structure of the back side of a back-contact battery cell according to an embodiment of this application. Detailed Implementation
[0022] As is known from the background technology, the arrangement of P and N regions with interdigitated spacing will cause the leakage channel to affect the entire battery cell, amplifying the effect of the leakage channel, thereby significantly reducing the open circuit voltage and short circuit current of the battery.
[0023] like Figure 1 The diagram shows a back-contact solar cell structure in related technologies. The light gray area represents the P-region, the dark gray area represents the N-region, the white area represents the P- and N-isolation regions, and the blue lines represent metal grid lines. The metallization pattern is arranged in an interdigitated pattern in the P-region and the N-region.
[0024] Analysis revealed that when fabricating interdigitated P-regions and N-regions on the back of back-contact solar cells, laser + wet etching is often used. The gaps between the P-regions and N-regions are isolated by wet etching trenches. However, incomplete trench etching can lead to incomplete isolation of some P-regions and N-regions, resulting in leakage channels. The existing metallization pattern on the back of back-contact solar cells amplifies the impact of these leakage channels on the entire cell, significantly reducing the open-circuit voltage and short-circuit current of the cell.
[0025] Therefore, this application provides a back-contact solar cell, comprising: a silicon wafer substrate and an electrode layer disposed on the back side of the silicon wafer substrate, the electrode layer comprising a plurality of parallel electrode regions; each electrode region comprising a first grid line group and a second grid line group with the opposite polarity to the first grid line group; the first grid line group comprising a first bus grid line extending along a first direction and a first main grid line connected to the first bus grid line, the endpoint of the first main grid line away from the first bus grid line being connected to a first fine grid line; the first fine grid line extending along the first direction, and a plurality of first main grid lines extending along a second direction, the second direction being different from the first direction; the second grid line group comprising a second bus grid line extending along the first direction and a second main grid line connected to the second bus grid line, the endpoint of the second main grid line away from the second bus grid line being connected to a second fine grid line; the second fine grid line extending along the first direction, and a plurality of second main grid lines extending along the second direction; the first main grid line and the second main grid line are spaced apart along the first direction and staggered along the second direction, and the first fine grid line and the second fine grid line are spaced apart along the second direction and staggered along the first direction.
[0026] This embodiment divides the electrode layer into multiple electrode regions, with each electrode region having its own grid lines. Even if a leakage channel is generated in the isolation area of the back contact solar cell, the leakage channel only affects the corresponding electrode region, not the entire cell. This reduces the impact of the leakage channel on the entire cell and improves the cell's open-circuit voltage and short-circuit current.
[0027] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined. Similarly, "multiple sets" refers to two or more sets (including two sets), and "multiple pieces" refers to two or more pieces (including two pieces).
[0028] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.
[0029] In the description of the embodiments in this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent three cases: A exists, A and B exist simultaneously, and B exists. In addition, the character " / " in this document generally indicates that the related objects before and after are in an "or" relationship.
[0030] In the description of the embodiments of this application, the technical terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential," etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings. They are used only for the convenience of describing the embodiments of this application and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this application. For example, if the device or element in the illustration is inverted, then the element described as "below," "under," "down," or "bottom" of other elements or features will be oriented "above" or "top" of the other elements or features. Therefore, the term "below" may, depending on the context in which the term is used, encompass both above and below orientations, which will be obvious to those skilled in the art. Materials may be oriented in other ways (e.g., rotated 90 degrees, inverted, flipped), and the spatial relative descriptive terms used herein may be interpreted accordingly.
[0031] In the description of the embodiments of this application, unless otherwise expressly specified and limited, technical terms such as "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.
[0032] In the accompanying drawings corresponding to the embodiments of this application, some structures are enlarged for better understanding and ease of description. Furthermore, when describing a component as "generally" formed on another component, it means that the component is not formed on the entire surface (or front surface) of the other component, nor is it formed on a portion of the edge of the entire surface.
[0033] In the description of the embodiments of this application, when a component "includes" another component, other components are not excluded unless otherwise stated, and other components may be further included. The formation or provision of a second component above or on a first component, or on the surface of a first component, or on one side of a first component, may include embodiments where the first and second components are in direct contact, and may also include embodiments where an additional component may be present between the first and second components, thereby preventing direct contact between the first and second components. For simplicity and clarity, various components may be drawn at different scales. In the drawings, some layers / components may be omitted for simplicity. Unless otherwise specified, the formation or provision of a second component on the surface of a first component refers to direct contact between the first and second components. The term "component" may refer to a layer, film, region, portion, structure, etc.
[0034] The terminology used in the description of the various embodiments herein is for the purpose of describing particular embodiments only and is not intended to be limiting. As used in the description of the various embodiments and the appended claims, the term "component" is also intended to include the plural form unless the context clearly indicates otherwise. Components include layers, films, regions, or plates, etc.
[0035] The embodiments of this disclosure will now be described in detail with reference to the accompanying drawings. However, those skilled in the art will understand that many technical details have been provided in the embodiments of this disclosure to facilitate a better understanding of the disclosure. However, the technical solutions claimed in this disclosure can be implemented even without these technical details and various variations and modifications based on the following embodiments.
[0036] Figure 2 This is a schematic diagram of the structure of the back contact solar cell in this embodiment. The back contact solar cell in this embodiment includes: a silicon wafer substrate 1 and an electrode layer 2 disposed on the back side of the silicon wafer substrate 1. The electrode layer 2 includes a plurality of parallel electrode regions 20. Each electrode region 20 is provided with a first grid line group 21 and a second grid line group 22 with the opposite polarity to the first grid line group 21.
[0037] refer to Figure 2In the figure, the first direction is horizontal, and the second direction is vertical. The first grid line group 21 includes a first busbar 211 extending along the first direction and at least one first main grid line 212 connected to the first busbar 211. The endpoint of the first main grid line 212 away from the first busbar 211 is connected to a first fine grid line 213. The first fine grid line 213 extends along the first direction, and multiple first main grid lines 212 extend along a second direction, which is different from the first direction. The second grid line group 22 includes a second busbar 221 extending along the first direction and at least one... The second main grid line 222 has its endpoint away from the second busbar 221 connected to the second fine grid line 223; the second fine grid line 223 extends along the first direction, and multiple second main grid lines 222 extend along the second direction; the first main grid line 212 and the second main grid line 222 are arranged at intervals along the first direction and staggered along the second direction, and between adjacent first main grid lines 212 and second main grid lines 222, the corresponding first fine grid lines 213 and second fine grid lines 223 are arranged at intervals along the second direction and staggered along the first direction.
[0038] Specifically, the silicon substrate 1 of the back-contact solar cell can be either an N-type or P-type silicon wafer. To improve light absorption efficiency, the surface of the silicon substrate 1 is typically texturized to form a pyramidal textured structure. This structure increases the number of light reflections on the silicon surface, thereby improving light absorption. The back side of the silicon substrate 1 has an electrode region 20 and a contact area connecting the electrode region 20 to the fine grid lines. The back side of the silicon substrate 1 typically undergoes special treatments, such as the fabrication of a passivation layer and a selective contact layer. For example, in a back-contact solar cell, the back side may have an ultrathin layer of silicon oxide and a layer of doped polycrystalline silicon thin film. This structure effectively reduces carrier recombination and improves the open-circuit voltage of the cell.
[0039] In a back-contact solar cell, the back side of the silicon substrate 1 includes P-type doped regions and N-type doped regions, such as... Figure 2 As shown, the light gray area is the P-type doped region, the dark gray area is the N-type doped region, the white area is the P- and N-isolation region, and the blue line is the metal grid line. In this embodiment, the first grid line group 21 is used to connect the P-type doped region in the electrode region 20, and the second grid line group 22 is used to connect the N-type doped region in the electrode region 20. The formation of these regions is crucial to the current collection and conversion efficiency of the battery.
[0040] refer to Figure 2Each electrode region 20 has the same grid line arrangement structure. The first grid line group 21 includes a plurality of first main grid lines 212 connected to the first bus grid line 211, and the plurality of first main grid lines 212 are arranged along the first direction. The second grid line group 22 includes a plurality of second main grid lines 222 connected to the second bus grid line 221, and the plurality of second main grid lines 222 are arranged along the first direction. The plurality of first main grid lines 212 and the plurality of second main grid lines 222 are arranged at intervals along the first direction and staggered along the second direction.
[0041] refer to Figure 2 Each electrode region 20 is provided with a first main gate line 212 located on the edge side and a second main gate line 222 located on the edge side; the first main gate line 212 and the second main gate line 222 located on the edge side are respectively located on the two edge sides of the electrode region 20. That is, for each electrode region 20, a first main gate line 212 is provided on one edge side of the electrode region 20, and a second main gate line 222 is provided on the other edge side of the electrode region 20.
[0042] Specifically, the endpoint of the first main grid line 212 located on the edge side, away from the first bus grid line 211, is connected to the endpoint of a first fine grid line 213; the endpoint of the second main grid line 222 located on the edge side, away from the second bus grid line 221, is connected to the endpoint of a second fine grid line 223; the endpoint of the first main grid line 212 located on the non-edge side, away from the first bus grid line 211, is connected to the center point of the first fine grid line 213, that is, the first fine grid line 213 is symmetrically arranged with the first main grid line 212 as the center line; the endpoint of the second main grid line 222 located on the non-edge side, away from the second bus grid line 221, is connected to the center point of the second fine grid line 223; that is, the second fine grid line 223 is symmetrically arranged with the second main grid line 222 as the center line.
[0043] Specifically, in this embodiment, the first main grid line 212 has a first fine grid line 213 only at its endpoints away from the first bus grid line 211, and the second main grid line 222 has a second fine grid line 223 only at its endpoints away from the second bus grid line 221. In this way, with the same area of the back-contact solar cell, the number of electrode regions 20 can be maximized. Even if a leakage current channel is generated in the isolation area of the back-contact solar cell, the area of the corresponding electrode region 20 affected by the leakage current channel is relatively small, further improving the open-circuit voltage and short-circuit current of the cell.
[0044] like Figure 3The diagram shows a specific structural schematic of another back-contact battery cell in this embodiment. In this embodiment, the endpoint of the first main grid line 212 away from the first busbar 211 is provided with a first fine grid line 213, and the endpoint of the second main grid line 222 away from the second busbar 221 is provided with a second fine grid line 223. Furthermore, the non-endpoint region of the first main grid line 212 located on the edge side is also connected to the endpoint of at least one third fine grid line 214, and the non-endpoint region of the first main grid line 212 located on the non-edge side is also connected to the center point of at least one third fine grid line 214. The third fine grid line 214 and the first fine grid line 213 are arranged along a second direction. The non-endpoint region of the second main gate line 222 is also connected to the endpoint of at least one fourth fine gate line 224, and the non-endpoint region of the first main gate line 212 located on the non-edge side is also connected to the center point of at least one fourth fine gate line 224; the fourth fine gate line 224 and the second fine gate line 223 are arranged at intervals along the second direction; between adjacent first main gate lines 212 and second main gate lines 222, the third fine gate line 214 and the fourth fine gate line 224 are arranged at intervals along the second direction and staggered along the first direction; wherein, a first main gate line 212 is provided on one edge side of the electrode region 20, and a second main gate line 222 is provided on the other edge side of the electrode region 20.
[0045] like Figure 3 As shown, one end of the first main grid line 212 is connected to the first bus grid line 211, the non-endpoint region of the first main grid line 212 is connected to at least one third fine grid line 214, and the end of the first main grid line 212 away from the first bus grid line 211 is connected to the first fine grid line 213; one end of the second main grid line 222 is connected to the second bus grid line 221, the non-endpoint region of the second main grid line 222 is connected to at least one fourth fine grid line 224, and the end of the second main grid line 222 away from the second bus grid line 221 is connected to the second fine grid line 223. For adjacent first main grid lines 212 and second main grid lines 222, in the second direction, the first fine grid line 213, the second fine grid line 223, the third fine grid line 214, and the fourth fine grid line 224 are arranged sequentially, and in the first direction, the first fine grid line 213, the second fine grid line 223, the third fine grid line 214, and the fourth fine grid line 224 are arranged alternately.
[0046] Embodiments of this application also provide a photovoltaic module, such as... Figure 4 The diagram shown is a cross-sectional view of the photovoltaic module in this embodiment. Figure 5 The diagram shown is a structural schematic of the back side of the back contact solar cell in this embodiment. The photovoltaic module in this embodiment includes: a panel 100, a cell string 200, and a back sheet 300 stacked in sequence; the cell string 300 is composed of multiple back contact solar cells as described above.
[0047] refer to Figure 5The back of the battery also has a first solder ribbon 23 and a second solder ribbon 24. The first solder ribbon 23 is sequentially connected to the first main grid line 212 of each electrode region and covers the first main grid line 212 of each electrode region. Since there is an overlap area between the first solder ribbon 23 and the second bus grid line 221 while the first solder ribbon 23 is covering the first main grid line 212, it affects the efficiency of collecting holes in the P region. Therefore, insulating adhesive is provided in the overlap area between the first solder ribbon 23 and the second bus grid line 221 to isolate the first solder ribbon 23 from the second bus grid line 221. To improve the efficiency of collecting holes in the P-region, the second solder ribbon 24 is sequentially connected to the second main grid line 222 of each electrode region. The second solder ribbon 24 covers the second main grid line 222 of each electrode region. Since there is an overlap between the second solder ribbon 24 and the first bus grid line 211 while the second solder ribbon 24 covers the second main grid line 222, it will affect the efficiency of collecting electrons in the N-region. Therefore, insulating adhesive is set in the overlap area of the second solder ribbon 24 and the first bus grid line 211 to isolate the second solder ribbon 24 from the first bus grid line 211 and improve the efficiency of collecting electrons in the N-region.
[0048] Specifically, between two adjacent back-contact solar cells, the first solder strip 23 of one back-contact solar cell is connected to the second solder strip 24 of the other back-contact solar cell, thereby connecting multiple back-contact solar cells in series to form a solar cell string. This connection method helps to reduce or eliminate the gap between two adjacent back-contact solar cells, increase the light-receiving area of the solar cell string, and improve light utilization. The photovoltaic module includes multiple solar cell strings, and adjacent solar cell strings are electrically connected through busbars, thereby realizing the current collection and output of multiple solar cell strings to ensure the efficient operation and stability of the photovoltaic module.
[0049] Specifically, the panel is the light-receiving surface of the photovoltaic module, and the backsheet is the backlighting surface. Multiple silicon wafer substrates for the back-contact solar cells are mounted on the panel, and the backsheet covers the electrode layers of the back-contact solar cells. The panel can be a transparent polymer material, such as ethylene-tetrafluoroethylene copolymer (ETFE), polyvinylidene fluoride (PVF), or polyvinylidene difluoride (PVDF), to reduce the weight of the photovoltaic module and improve its stability. The backsheet can be a composite backsheet, for example, composed of a fluorocarbon film, a polyester film (PET), and an adhesive. It can also be a coated backsheet, for example, a fluoropolymer coating applied to a PET base film. Furthermore, the backsheet can be transparent.
[0050] Those skilled in the art will understand that the above embodiments are specific examples of implementing this disclosure, and in practical applications, various changes in form and detail may be made without departing from the spirit and scope of this disclosure. Any person skilled in the art can make various alterations and modifications without departing from the spirit and scope of this disclosure; therefore, the scope of protection of this disclosure should be determined by the scope defined in the claims.
[0051] Those skilled in the art will understand that the above embodiments are specific examples of implementing this disclosure, and in practical applications, various changes in form and detail may be made without departing from the spirit and scope of this disclosure. Any person skilled in the art can make various alterations and modifications without departing from the spirit and scope of this disclosure; therefore, the scope of protection of this disclosure should be determined by the scope defined in the claims.
Claims
1. A back contact battery cell, characterized in that, include: A silicon wafer substrate (1) and an electrode layer (2) disposed on the back side of the silicon wafer substrate (1), the electrode layer (2) comprising a plurality of parallel electrode regions (20); each electrode region (20) is provided with a first gate line group (21) and a second gate line group (22) with the opposite polarity to the first gate line group (21); The first grid line group (21) includes a first bus grid line (211) extending along a first direction and a first main grid line (212) connected to the first bus grid line (211). The first main grid line (212) is connected to a first fine grid line (213) at its endpoint away from the first bus grid line (211). The first fine grid line (213) extends along the first direction, and the first main grid line (212) extends along a second direction, which is different from the first direction. The second gate line group (22) includes a second bus gate line (221) extending along the first direction and a second main gate line (222) connected to the second bus gate line (221). The endpoint of the second main gate line (222) away from the second bus gate line (221) is connected to a second fine gate line (223). The second fine gate line (223) extends along the first direction, and a plurality of second main gate lines (222) extend along the second direction. The first main grid line (212) and the second main grid line (222) are arranged at intervals along the first direction and staggered along the second direction, and the first fine grid line (213) and the second fine grid line (223) are arranged at intervals along the second direction and staggered along the first direction.
2. The back contact battery cell according to claim 1, characterized in that, The first gate line group (21) includes a plurality of first main gate lines (212) connected to the first bus gate line (211); The second grid line group (22) includes a plurality of second main grid lines (222) connected to the second bus grid line (221); the plurality of first main grid lines (212) and the plurality of second main grid lines (222) are arranged at intervals along the first direction and staggered along the second direction.
3. The back contact battery cell according to claim 1, characterized in that, The endpoint of the first main grid line (212) located on the non-edge side, away from the first bus grid line (211), is connected to the center point of the first fine grid line (213); the endpoint of the second main grid line (222) located on the non-edge side, away from the second bus grid line (221), is connected to the center point of the second fine grid line (223).
4. The back contact battery cell according to claim 3, characterized in that, The endpoint of the first main grid line (212) located on the edge side, away from the first bus grid line (211), is connected to the endpoint of a first fine grid line (213); the endpoint of the second main grid line (222) located on the edge side, away from the second bus grid line (221), is connected to the endpoint of a second fine grid line (223).
5. The back contact battery cell according to claim 3 or 4, characterized in that, The non-endpoint region of the first main gate line (212) located on the non-edge side is also connected to the center point of at least one third fine gate line (214), which is arranged with the first fine gate line (213) along the second direction.
6. The back contact battery cell according to claim 5, characterized in that, The non-endpoint region of the second main gate line (222) located on the non-edge side is also connected to the center point of at least one fourth fine gate line (224), which is arranged with the second fine gate line (223) along the second direction; the third fine gate line (214) and the fourth fine gate line (224) are arranged at intervals along the second direction and staggered along the first direction.
7. The back contact battery cell according to claim 6, characterized in that, The non-endpoint region of the first main gate line (212) located in the edge region is also connected to the endpoint of at least one of the third fine gate lines (214), and the non-endpoint region of the second main gate line (222) located in the edge region is also connected to the endpoint of at least one of the fourth fine gate lines (224).
8. The back contact battery cell according to claim 1, characterized in that, The silicon substrate (1) is an N-type silicon wafer or a P-type silicon wafer.
9. A photovoltaic module, comprising: A panel (100), a battery string (200), and a backplate (300) are stacked in sequence; the battery string is composed of a plurality of back-contact battery cells as described in any one of claims 1-8.
10. The photovoltaic module according to claim 9, characterized in that, The back of the back contact battery is also provided with a first solder strip (23) and a second solder strip (24). The first solder strip (23) is sequentially connected to the first main grid line (212) of each electrode region (20), and the second solder strip (24) is sequentially connected to the second main grid line (222) of each electrode region (20).