Back contact battery piece, battery assembly and photovoltaic system

Abstract

The invention is applicable to the field of photovoltaic technology, and provides a back contact battery piece, a battery assembly and a photovoltaic system, and the back contact battery piece comprises a substrate which is provided with a first surface and a second surface which are oppositely arranged; the first confluence structure and the second confluence structure are arranged on the first surface at intervals in the first direction; according to the above structural design, the confluence structure of the first surface is arranged to partially penetrate through the substrate to be connected with the interconnection structure of the second surface, and the confluence structure of the first surface of one of two adjacent battery pieces is in direct lap joint with the interconnection structure of the second surface of the other battery piece to achieve interconnection between the adjacent battery pieces. A welding strip is not needed, the moving distance of a carrier is shortened, input of series welding machine equipment is omitted, the process production steps of the cell assembly are simplified, adjacent cell pieces are overlapped and interconnected, the distance between the cell pieces is eliminated, and the power density of the assembly is further improved.

Description

Technical Field

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

[0002] Solar cells, also known as photovoltaic cells, are devices that directly convert light energy into direct current (DC) using the photovoltaic effect. The PN junction on the semiconductor in a solar cell can directly convert solar energy into electrical energy through the photovoltaic effect. Solar cells are typically sheet-shaped. Solar cells with both electrodes of different polarities formed on the back of the cell are called back-contact cells. Currently, back-contact solar cells (such as IBC, MWT, and EWT solar cells) have received widespread attention. Because they have no grid lines or even any electrode patterns on the front side, with both the positive and negative electrodes located on the back of the cell, they reduce shading and effectively increase the short-circuit current, thus improving the energy conversion efficiency. However, existing back-contact solar cells have electrodes located on the back of the cell, requiring the use of solder ribbons for stringing. This prevents them from being directly stacked and connected to form a string like traditional crystalline silicon solar cells.

[0003] Application content

[0004] This application provides a back-contact solar cell, which aims to solve the problem that the electrodes of existing back-contact solar cells are all located on the back of the cell, requiring the use of solder ribbons for stringing, and cannot be directly stacked and arranged to connect the positive and negative electrodes of adjacent cells to form a cell string, as is the case with traditional crystalline silicon solar cells.

[0005] This application is implemented as follows: a back-contact battery cell includes a substrate having a first surface and a second surface disposed opposite to each other; a first bus structure and a second bus structure spaced apart on the first surface along a first direction; a first grid structure and a second grid structure disposed between the first bus structure and the second bus structure, the first grid structure being connected to the first bus structure and the second grid structure being connected to the second bus structure; a first interconnect structure disposed on the second surface, the first bus structure at least partially passing through the substrate and connected to the first interconnect structure; and / or a second interconnect structure disposed on the second surface, the second bus structure at least partially passing through the substrate and connected to the second interconnect structure.

[0006] In this application, through the above-described structural design, the busbar structure of the first surface is configured to partially pass through the substrate and connect to the interconnection structure of the second surface. The busbar structure of the first surface of one of the two adjacent cells is directly connected to the interconnection structure of the second surface of the other cell to achieve interconnection between the adjacent cells. No solder strip is required, which shortens the movement distance of charge carriers, saves the investment in string welding equipment, simplifies the process production steps of the battery module, and the overlapping interconnection between adjacent cells eliminates the gap between cells, further improving the power density of the module.

[0007] Optionally, the first gate line structure includes at least one of a first electrode pattern structure and a second electrode pattern structure.

[0008] Optionally, the first electrode pattern structure includes a plurality of first fine gates, which extend along the first direction and are spaced apart along the second direction, and each first fine gate is connected to the first bus structure.

[0009] Optionally, the second electrode pattern structure includes a plurality of first main gates spaced apart along the first direction and a plurality of first sub-gates respectively cross-connected to the plurality of first main gates, each of the first main gates being connected to the first bus structure.

[0010] Optionally, the second gate structure includes at least one of a third electrode pattern structure and a fourth electrode pattern structure.

[0011] Optionally, the third electrode pattern structure includes a plurality of second fine gates, which extend along the first direction and are spaced apart along the second direction, and each second fine gate is connected to the second bus structure.

[0012] Optionally, the fourth electrode pattern structure includes a plurality of second main gates spaced apart along the first direction and a plurality of second sub-gates respectively cross-connected to the plurality of second main gates, each of the second main gates being connected to the second bus structure.

[0013] Optionally, the substrate has at least one first through-hole, through which the first bus structure is connected to the first interconnect structure.

[0014] Optionally, the diameter of the first through hole ranges from 50 to 500 μm.

[0015] Optionally, the minimum distance from the center of the first through hole to the edge of the substrate is greater than or equal to 1.5 mm.

[0016] Optionally, the substrate has at least one second through-hole, through which the second bus structure is connected to the second interconnect structure.

[0017] Optionally, the diameter of the second through hole ranges from 50 to 500 μm.

[0018] Optionally, the minimum distance from the center of the second through hole to the edge of the substrate is greater than or equal to 1.5 mm.

[0019] Optionally, the first interconnection structure includes a plurality of first interconnection modules, which are spaced apart in the second direction.

[0020] Optionally, the first interconnect structure includes a first interconnect gate line extending along a second direction.

[0021] Optionally, the second interconnection structure includes a plurality of second interconnection modules, which are spaced apart in a second direction.

[0022] Optionally, the second interconnect structure includes a second interconnect gate line extending along a second direction.

[0023] Optionally, the first bus structure includes a plurality of first bus modules, which are spaced apart in the second direction.

[0024] Optionally, the first bus structure includes a first bus grid line extending along a second direction.

[0025] Optionally, the second bus structure includes a plurality of second bus modules, which are spaced apart in a second direction.

[0026] Optionally, the second bus structure includes a second bus grid line extending along a second direction.

[0027] A battery assembly includes the aforementioned battery cells, wherein a plurality of the battery cells are partially overlapped in a first direction, wherein the first bus structure on the first surface of one of two adjacent battery cells and the second interconnect structure on the second surface of the other are in conductive contact, and / or the second bus gate structure on the first surface of one of two adjacent battery cells and the first interconnect structure on the second surface of the other are in conductive contact.

[0028] Optionally, a conductive material is provided in the overlapping area between the plurality of battery cells, the conductive material including conductive adhesive or conductive silver paste.

[0029] A photovoltaic system includes the aforementioned battery module. The technical effects of this application are the same as those of the aforementioned battery module, and will not be repeated here. Attached Figure Description

[0030] Figures 1 to 10These are schematic diagrams of various embodiments of the back contact battery cells provided in this application;

[0031] Figures 11 to 13 These are schematic diagrams of various embodiments of the battery assembly provided in this application.

[0032] Explanation of reference numerals in the attached figures:

[0033] 100, Substrate; 101, First surface; 102, Second surface; 200, First bus structure; 201, First bus module; 300, Second bus structure; 301, Second bus module; 400, First gate line structure; 401, First electrode pattern; 4011, First fine gate; 402, Second electrode pattern; 4021, First main gate; 4022, First sub-gate; 500, Second gate line structure; 501, Third electrode pattern; 5011, Second fine gate; 502, Fourth electrode pattern; 5021, Second main gate; 5022, Second sub-gate; 600, First interconnect structure; 601, First interconnect module; 700, Second interconnect structure; 701, Second interconnect module; 800, First via; 900, Second via. Detailed Implementation

[0034] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application. Furthermore, it should be understood that the specific embodiments described herein are merely for explaining this application and are not intended to limit this application.

[0035] In the description of this application, it should be understood that the terms "length", "width", "upper", "lower", "left", "right", "horizontal", "top", "bottom", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0036] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the stated features. In the description of this application, "a plurality of" means two or more, unless otherwise explicitly specified.

[0037] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0038] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature being directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0039] The following disclosure provides numerous different embodiments or examples for implementing various structures of this application. To simplify the disclosure, specific examples of components and arrangements are described below. These are merely examples and are not intended to limit the scope of this application. Furthermore, reference numerals and / or letters may be repeated in different examples; such repetition is for simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or arrangements discussed. In addition, various specific examples of processes and materials are provided in this application, but those skilled in the art will recognize the application of other processes and / or the use of other materials.

[0040] like Figures 1 to 10 As shown, a back-contact solar cell includes a substrate 100, which has a first surface 101 and a second surface 102 disposed opposite to each other. The substrate 100 serves as the support and foundation of the solar cell and exhibits excellent semiconductor performance and mechanical stability. The material of the substrate 100 can be an elemental semiconductor material. Specifically, the elemental semiconductor material is composed of a single element, such as silicon or germanium. The elemental semiconductor material can be monocrystalline, polycrystalline, amorphous, or microcrystalline (a state simultaneously possessing monocrystalline and amorphous states is called microcrystalline). For example, silicon can be at least one of monocrystalline silicon, polycrystalline silicon, amorphous silicon, or microcrystalline silicon. Preferably, the substrate 100 is made of n-type monocrystalline silicon, which is free from photo-induced degradation.

[0041] The substrate 100 has a first surface 101 and a second surface 102 disposed opposite to each other. In one embodiment of this application, the substrate 100 has a front side facing the sun during normal operation and a back side opposite to the front side, the front side being the light-receiving surface; the back side is disposed on the other side of the substrate 100 opposite to the front side, that is, the aforementioned front side and back side are located on different sides of the substrate 100 and are opposite sides. In this embodiment, the first surface 101 is the backlighting surface and the second surface 102 is the light-receiving surface.

[0042] A first busbar structure 200 and a second busbar structure 300 are spaced apart on a first surface 101 along a first direction. A first grid line structure 400 and a second grid line structure 500 are disposed between the first busbar structure 200 and the second busbar structure 300. The first grid line structure 400 is connected to the first busbar structure 200, and the second grid line structure 500 is connected to the second busbar structure 300. Understandably, the grid line structure is used to collect photogenerated carriers generated inside the solar cell, and the busbar structure is used to combine the carriers generated by the grid line structure. The first grid line structure 400 and the second grid line structure 500 are arranged at intervals across the entire backlight surface of the solar cell, and are respectively disposed in different doped regions of the solar cell. The polarities of the first grid line structure 400 and the second grid line structure 500 are opposite. For example, the first grid line structure 400 can be a positive grid line, and the second grid line structure 500 can be a negative grid line, or the first grid line structure 400 can be a negative grid line, and the second grid line structure 500 can be a positive grid line. This application does not limit this. The first bus structure 200 and the second bus structure 300 are respectively arranged at the edges of the backlight surface of the solar cell. The first bus structure 200 is used to combine the charge carriers collected by the first grid line structure 400, and the second bus structure 300 is used to combine the charge carriers collected by the second grid structure 500.

[0043] Specifically, in this embodiment, the battery cell further includes a first interconnect structure 600 disposed on the second surface 102. A first bus structure 200 at least partially passes through the substrate 100 and is connected to the first interconnect structure 600. That is, the first interconnect structure 600 is disposed on the light-facing side of the battery cell, and at least a portion of the first bus structure 200 passes through the substrate 100 and is connected to the first interconnect structure 600 to achieve electrical conduction. This allows current generated on the backlight side of the battery cell to be transmitted to the light-facing side. Preferably, the first bus structure 200 and the first interconnect structure 600 are disposed opposite each other in the thickness direction of the substrate 100. This allows the first bus structure 200 to be directly connected to the first interconnect structure 600 through a through-hole, saving on paste usage. Of course, in other embodiments, the first bus structure 200 and the first interconnect structure 600 can also be staggered in the thickness direction of the substrate 100. The first bus structure 200 and the first interconnect structure 600 can be flexibly arranged independently of each other, and this application does not impose any limitations on this. The solar cell also includes a second interconnect structure 700 disposed on the second surface 102, and a second bus structure 300 at least partially passes through the substrate 100 and is connected to the second interconnect structure 700. That is, the second interconnect structure 700 is disposed on the light-facing side of the solar cell, and at least a portion of the second bus structure 300 passes through the substrate 100 and is connected to the second interconnect structure 700 to achieve electrical conduction, thereby transmitting the current generated on the backlight side of the solar cell to the light-facing side. Preferably, the second bus structure 300 and the second interconnect structure 700 are disposed opposite each other in the thickness direction of the substrate 100, so that the second bus structure 300 can be directly connected to the second interconnect structure 700 through a through-hole, saving the use of paste. Of course, in other embodiments, the second bus structure 300 and the second interconnect structure 700 can also be staggered in the thickness direction of the substrate 100, and the second bus structure 300 and the second interconnect structure 700 can be flexibly arranged independently of each other; this application does not impose any limitations on this.

[0044] In this way, when multiple solar cells are connected in series to form a solar module, the busbar structure on the first surface 101 of one of the adjacent solar cells and the interconnection structure on the second surface 102 of the other solar cell can be directly overlapped to achieve interconnection between the adjacent solar cells. No solder strip is required, which shortens the movement distance of charge carriers, saves the investment in string welding equipment, simplifies the process production steps of solar modules, and the overlapping interconnection between adjacent solar cells eliminates the gap between solar cells, further improving the power density of the module.

[0045] In some embodiments, the first gate line structure 400 includes at least one of a first electrode pattern 401 structure and a second electrode pattern 402 structure. That is, the first gate line structure 400 may be only the first electrode pattern 401 structure, or the first gate line structure 400 may be only the second electrode pattern 402 structure, or the first gate line structure 400 may be a combination of the first electrode pattern 401 structure and the second electrode pattern 402 structure.

[0046] Specifically, the first electrode pattern 401 structure includes multiple first fine grids 4011, which extend along a first direction and are spaced apart along a second direction. Each first fine grid 4011 is connected to the first busbar structure 200. This structural arrangement simplifies the design of the electrode pattern. Each first fine grid 4011 independently collects the charge carriers inside the solar cell. Each first fine grid 4011 is independently and directly connected to the first busbar structure 200, ensuring that the current collected by each first fine grid 4011 flows into the first busbar structure 200 via the shortest path. This reduces the resistance loss of current in the fine grid network. Even if individual first fine grids 4011 experience problems during manufacturing or use (such as breakage), it will not affect the normal operation of other first fine grids 4011, ensuring long-term reliability.

[0047] Specifically, the second electrode pattern 402 structure includes a plurality of first main gates 4021 spaced apart along a first direction and a plurality of first sub-gates 4022 respectively cross-connected to the plurality of first main gates 4021. Each first main gate 4021 is connected to the first bus structure 200. In this embodiment, the plurality of first main gates 4021 and the plurality of first sub-gates 4022 are cross-connected to form a network structure. This mesh structure shortens the current transmission path to the extreme. The current generated at any point in the solar cell only needs to be transmitted to the nearest first sub-gate 4022, and then quickly "captured" and carried away by the first main gate 4021 through the nearest intersection point. This greatly reduces the transmission distance of lateral current in the semiconductor and the resistance loss.

[0048] In some embodiments, the second gate line structure 500 includes at least one of a third electrode pattern structure 501 and a fourth electrode pattern structure 502. That is, the second gate line structure 500 may be only the third electrode pattern structure 501, or the second gate line structure 500 may be only the fourth electrode pattern structure 502, or the second gate line structure 500 may be a combination of the third electrode pattern structure 501 and the fourth electrode pattern structure 502.

[0049] Specifically, the third electrode pattern structure 501 includes a plurality of second fine grids 5011, which extend along a first direction and are spaced apart along a second direction. Each second fine grid 5011 is connected to the second bus structure 300. This structural arrangement simplifies the design of the electrode pattern. Each second fine grid 5011 independently collects charge carriers inside the solar cell, and each second fine grid 5011 is independently and directly connected to the second bus structure 300. This ensures that the current collected by each second fine grid 5011 can flow into the second bus structure 300 via the shortest path, reducing resistance loss in the grid network. Even if individual second fine grids 5011 experience problems during manufacturing or use (such as breakage), it will not affect the normal operation of other second fine grids 5011, ensuring long-term reliability.

[0050] Specifically, the fourth electrode pattern structure 502 includes a plurality of second main gates 5021 spaced apart along a first direction and a plurality of second sub-gates 5022 respectively cross-connected to the plurality of second main gates 5021. Each second main gate 5021 is connected to the second bus structure 300. In this embodiment, the plurality of second main gates 5021 and the plurality of second sub-gates 5022 are respectively cross-connected to form a network structure. This grid structure shortens the current transmission path to the extreme. The current generated at any point in the solar cell only needs to be transmitted to the nearest second sub-gate 5022, and then quickly "captured" and carried away by the second main gate 5021 through the nearest intersection point. This greatly reduces the transmission distance of lateral current in the semiconductor and the resistance loss.

[0051] In some embodiments, the substrate 100 has at least one first through-hole 800, through which the first bus structure 200 is connected to the first interconnect structure 600. Exemplarily, one or more micron-sized first through-holes 800 can be precisely drilled on the substrate 100 using a laser to form conductive channels, allowing the first bus structure 200 on the back side of the solar cell to be directly connected to the first interconnect structure 600 on the back side, forming a conductive contact structure on the front side of the solar cell.

[0052] Further, the pore size of the first through-hole ranges from 50 to 500 μm, preferably from 50 to 350 μm. Exemplarily, the pore size of the first through-hole can be 50 μm, 100 μm, 200 μm, 300 μm, 350 μm, 500 μm, etc., and this application does not impose any limitation thereon. By limiting the pore size of the first through-hole to the above range, it is possible to avoid damage to the substrate structure caused by an excessively large pore size, and also to avoid affecting the passage of slurry if the pore size is too small.

[0053] Furthermore, the minimum distance from the center of the first through hole to the edge of the substrate is greater than or equal to 1.5 mm. In other words, the distance between the center of the first through hole and the edge of the substrate closest to the first through hole is greater than or equal to 1.5 mm. This can avoid damage to the structure of the substrate edge caused by drilling and reduce the risk of microcracks in the substrate.

[0054] In some embodiments, the substrate 100 has at least one second via 900, through which the second bus structure 300 is connected to the second interconnect structure 700. Exemplarily, one or more micrometer-scale second vias 900 can be precisely drilled on the substrate 100 using a laser to form conductive channels, allowing the second bus structure 300 on the back side of the solar cell to be directly connected to the second interconnect structure 700 on the back side, forming a conductive contact structure on the front side of the solar cell.

[0055] Further, the pore size of the second through hole ranges from 50 to 500 μm, preferably from 50 to 350 μm. Exemplarily, the pore size of the second through hole can be 50 μm, 100 μm, 200 μm, 300 μm, 350 μm, 500 μm, etc., and this application does not impose any limitation thereon. By limiting the pore size of the second through hole to the above range, it is possible to avoid damage to the substrate structure caused by an excessively large pore size, and also to avoid affecting the passage of slurry if the pore size of the second through hole is too small.

[0056] Furthermore, the minimum distance from the center of the second through hole to the edge of the substrate is greater than or equal to 1.5 mm. In other words, the distance between the center of the second through hole and the edge of the substrate closest to the second through hole is greater than or equal to 1.5 mm. This can avoid damage to the structure of the substrate edge caused by drilling and reduce the risk of microcracks in the substrate.

[0057] Based on the aforementioned through-hole structure, during the fabrication of the back electrode (e.g., by screen printing silver paste), the silver paste fills the laser-drilled through-hole. After high-temperature sintering, the silver paste within the hole forms a robust, highly conductive channel, physically and electrically connecting the current-carrying structure on the back of the battery to the interconnection structure on the front, achieving current "bypassing." Current that could previously only be drawn from the back of the battery can now "flow" to the front through this hole, providing a structural basis for solderless series connection between battery cells.

[0058] In some embodiments, the first interconnect structure 600 includes a plurality of first interconnect modules 601, which are spaced apart in a second direction. That is, the first interconnect structure 600 can be a plurality of interconnect modules formed on the front side of the solar cell, saving paste loss and reducing costs without affecting the current transmission between solar cells.

[0059] In other embodiments, the first interconnect structure 600 includes a first interconnect grid line extending along a second direction, which simplifies the manufacturing process of the first interconnect grid line. The first interconnect grid line is a continuous linear structure, and the first bus structure 200 corresponding to different structure types can completely cover it, enabling the transmission of current to different positions on the back of the battery cell.

[0060] In some embodiments, the second interconnect structure 700 includes a plurality of second interconnect modules 701, which are spaced apart in a second direction. That is, the second interconnect structure 700 can be a plurality of interconnect modules formed on the front side of the solar cell, saving paste loss and reducing costs without affecting the current transmission between solar cells.

[0061] In some embodiments, the second interconnect structure 700 includes second interconnect grid lines extending along a second direction. This simplifies the fabrication process of the second interconnect grid lines, which are continuous linear structures. The second bus structure 300, corresponding to different structural types, can completely cover them, enabling current transmission to different locations on the back of the solar cell.

[0062] In some embodiments, the first bus structure 200 includes a plurality of first bus modules 201, which are spaced apart in a second direction. That is, the first bus structure 200 can be a plurality of bus modules formed on the back of the solar cell, which can save paste loss and reduce costs without affecting the current transmission between solar cells.

[0063] In some embodiments, the first bus structure 200 includes a first bus grid line extending along a second direction. This simplifies the manufacturing process of the first bus grid line, which is a continuous linear structure, facilitating the current collection function.

[0064] In some embodiments, the second bus structure 300 includes a plurality of second bus modules 301, which are spaced apart in a second direction. That is, the second bus structure 300 can be a plurality of bus modules formed on the back of the solar cell, which can save paste loss and reduce costs without affecting the current transmission between solar cells.

[0065] In some embodiments, the second bus structure 300 includes a second bus grid line extending along a second direction, which simplifies the manufacturing process of the second bus grid line. The second bus grid line is a continuous linear structure, which facilitates the function of current convergence.

[0066] like Figures 10 to 13As shown, in some embodiments, a battery module includes the aforementioned battery cells, wherein the battery cells can be divided into two, three, or four sections. Multiple battery cells are partially overlapped in a first direction. Specifically, the first busbar structure 200 of the first surface 101 of one adjacent battery cell and the second interconnection structure 700 of the second surface 102 of the other battery cell are in conductive contact, and / or the second busbar structure of the first surface 101 of one adjacent battery cell and the first interconnection structure 600 of the second surface 102 of the other battery cell are in conductive contact. In the battery module, through the above structural design, adjacent battery cells can be directly interconnected through the direct overlap of the busbar structure of one cell with the opposite-symmetric interconnection structure of the other, eliminating the need for solder strips. Charge carriers are directly connected through the busbar structure and the interconnection structure to form cross-cell transmission, shortening the lateral current flow distance. Furthermore, the solder strip-free structure eliminates the need for string welding equipment, simplifying the battery module manufacturing process. The overlapping interconnection of the interconnection structure and busbar structure of adjacent battery cells eliminates the spacing between battery cells, further improving the module's power density. Furthermore, conductive materials, such as conductive adhesive, conductive silver paste, or solder paste, are applied to the overlapping areas between multiple solar cells. The application of conductive materials enhances both the connection strength between the solar cells and the current transmission efficiency between them.

[0067] In some embodiments, a photovoltaic system includes the aforementioned battery modules. In this embodiment, the photovoltaic system can be applied in photovoltaic power plants, such as ground-mounted power plants, rooftop power plants, and floating power plants, and can also be applied to equipment or devices that utilize solar energy to generate electricity, such as user solar power supplies, solar streetlights, solar cars, and solar buildings. Of course, it is understood that the application scenarios of the photovoltaic system are not limited to these; that is, the photovoltaic system can be applied in all fields that require solar energy to generate electricity. Taking a photovoltaic power generation system network as an example, the photovoltaic system may include a photovoltaic array, a combiner box, and an inverter. The photovoltaic array may be an array combination of multiple battery modules; for example, multiple battery modules can form multiple photovoltaic arrays. The photovoltaic array is connected to the combiner box, which can collect the current generated by the photovoltaic array. The collected current flows through the inverter and is converted into AC power required by the mains power grid before being connected to the mains power grid to achieve solar power supply.

[0068] In the description of this specification, the use of terms such as "some embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples," etc., refers to specific features, structures, materials, or characteristics described in connection with the embodiments or examples, which are included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiments or examples. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0069] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A back contact battery cell, characterized in that, Includes a substrate having a first surface and a second surface disposed opposite to each other; and a first busbar structure and a second busbar structure disposed at a distance from each other on the first surface along a first direction; A first gate structure and a second gate structure are disposed between the first bus structure and the second bus structure, wherein the first gate structure is connected to the first bus structure and the second gate structure is connected to the second bus structure; A first interconnect structure disposed on the second surface, wherein the first bus structure passes at least partially through the substrate and is connected to the first interconnect structure; and / or a second interconnect structure disposed on the second surface, wherein the second bus structure passes at least partially through the substrate and is connected to the second interconnect structure.

2. The back contact battery cell as described in claim 1, characterized in that, The first gate line structure includes at least one of a first electrode pattern structure and a second electrode pattern structure.

3. The back contact battery cell as described in claim 2, characterized in that, The first electrode pattern structure includes a plurality of first fine gates, which extend along the first direction and are spaced apart along the second direction. Each first fine gate is connected to the first bus structure.

4. The back contact battery cell as described in claim 2, characterized in that, The second electrode pattern structure includes a plurality of first main gates spaced apart along the first direction and a plurality of first sub-gates respectively cross-connected to the plurality of first main gates, and each first main gate is connected to the first bus structure.

5. The back contact battery cell as described in claim 1, characterized in that, The second gate structure includes at least one of a third electrode pattern structure and a fourth electrode pattern structure.

6. The back contact battery cell as described in claim 5, characterized in that, The third electrode pattern structure includes a plurality of second fine gates, which extend along the first direction and are spaced apart along the second direction. Each second fine gate is connected to the second bus structure.

7. The back contact battery cell as described in claim 5, characterized in that, The fourth electrode pattern structure includes a plurality of second main gates spaced apart along the first direction and a plurality of second sub-gates respectively cross-connected to the plurality of second main gates, and each second main gate is connected to the second bus structure.

8. The back contact battery cell as described in claim 1, characterized in that, The substrate has at least one first through hole, through which the first bus structure is connected to the first interconnect structure.

9. The back contact battery cell as described in claim 8, characterized in that, The diameter of the first through hole ranges from 50 to 500 μm.

10. The back contact battery cell as described in claim 8, characterized in that, The minimum distance from the center of the first through hole to the edge of the substrate is greater than or equal to 1.5 mm.

11. The back contact battery cell as described in claim 1, characterized in that, The substrate has at least one second through hole, through which the second bus structure is connected to the second interconnect structure.

12. The back contact battery cell as described in claim 11, characterized in that, The diameter of the second through hole ranges from 50 to 500 μm.

13. The back contact battery cell as described in claim 11, characterized in that, The minimum distance from the center of the second through hole to the edge of the substrate is greater than or equal to 1.5 mm.

14. The back contact battery cell as described in claim 1, characterized in that, The first interconnection structure includes a plurality of first interconnection modules, which are spaced apart in the second direction.

15. The back contact battery cell as described in claim 1, characterized in that, The first interconnect structure includes a first interconnect gate line extending along a second direction.

16. The back contact battery cell as described in claim 1, characterized in that, The second interconnection structure includes a plurality of second interconnection modules, which are spaced apart in a second direction.

17. The back contact battery cell as described in claim 1, characterized in that, The second interconnect structure includes a second interconnect gate line extending along a second direction.

18. The back contact battery cell as described in claim 1, characterized in that, The first bus structure includes a plurality of first bus modules, which are spaced apart in the second direction.

19. The back contact battery cell as described in claim 1, characterized in that, The first bus structure includes a first bus grid line extending along a second direction.

20. The back contact battery cell as described in claim 1, characterized in that, The second bus structure includes a plurality of second bus modules, which are spaced apart in a second direction.

21. The back contact battery cell as described in claim 1, characterized in that, The second bus structure includes a second bus grid line extending along a second direction.

22. A battery assembly, characterized in that, The battery cell includes any one of claims 1-21, wherein a plurality of battery cells are partially overlapped in the first direction, wherein the first busbar structure on the first surface of one of two adjacent battery cells and the second interconnection structure on the second surface of the other are in conductive contact, and / or the second busbar structure on the first surface of one of two adjacent battery cells and the first interconnection structure on the second surface of the other are in conductive contact.

23. The battery assembly as claimed in claim 18, characterized in that, A conductive material is disposed in the overlapping area between the multiple battery cells, the conductive material including conductive adhesive or conductive silver paste.

24. A photovoltaic system, characterized in that, Includes the battery assembly described in any one of claims 22-23 above.

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