Solar cell and photovoltaic module
By adopting multi-slicing, high-density layout design and a solution to gradually decrease the front gate line in solar cells, the internal loss and heat spot risks of large-size crystalline silicon solar cells are solved, and the power generation power of photovoltaic modules is increased and the production cost is reduced.
Patent Information
- Application Number
- CN202421490471.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-06-27
- Publication Date
- 2025-06-20
- Estimated Expiration
- 2034-06-27
AI Technical Summary
Existing large-size crystalline silicon solar cells have severe internal losses, reduced power and hot spot risks during power generation, and the methods to increase the density of components are complex and costly.
The solar cell with multi-chip, high-density layout design reduces resistance loss through the gradual reduction of the front gate line, and optimizes the current collection and welding process through the multi-chip structure and welding tape connection.
The power generation power of photovoltaic modules is increased by about 2.5%, reducing production costs, enhancing the mechanical strength and durability of the modules, and reducing the amount of silver paste used.
Smart Images
Figure CN223007835U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of photovoltaics, in particular to a solar cell and a photovoltaic module. Background Art
[0002] In order to improve the power generation efficiency of photovoltaic modules, one of the commonly used solutions is to use large-sized crystalline silicon solar cells. Such large-sized crystalline silicon solar cells are usually installed in photovoltaic modules in the form of half cells. Since large-sized cells can collect more solar energy, generating larger current and voltage, their internal losses are also more serious, which will lead to power reduction and increase the risk of hot spots.
[0003] Another method to improve power generation efficiency is to increase the layout density of the module. To achieve this design, a flat solder ribbon is required to complete the welding scheme of the cell string, such as a triangular segmented solder ribbon. This welding scheme involves processes such as image recognition and alignment modules, which is relatively complex, and the cost of the solder ribbon is high, and the production efficiency is low. Summary of the Invention
[0004] Therefore, the utility model provides a solar cell and a photovoltaic module, which are applicable to the module design of large-sized cell pieces, adopt design schemes such as multi-segmentation and high-density layout, optimize the internal current collection method of large-sized cells, further reduce the distance between cell pieces, increase the density of cell pieces, and thus achieve the goals of improving the power generation efficiency of the module and reducing the production and manufacturing cost.
[0005] To solve the above technical problems, the utility model provides a solar cell, comprising:
[0006] A cell piece body;
[0007] Multiple front grid lines arranged at intervals along the first direction of the cell piece body and extending along the second direction, both ends of each front grid line are respectively connected to pads located at the edges of both ends of the cell piece body in the second direction, and the back of the cell piece body is provided with back main grids corresponding to each of them, and the first direction arrangement is perpendicular to the second direction;
[0008] Wherein, the width of the front grid line gradually becomes smaller along the second direction.
[0009] In an embodiment of the utility model, the front grid line is in the shape of an isosceles trapezoid.
[0010] In an embodiment of the utility model, the width of the wide part of the front grid line is 2 ± 0.5 mm, and the width of the narrow part is 0.8 ± 0.2 mm.
[0011] In an embodiment of the utility model, the radial dimension of the pad is not less than 3 mm.
[0012] In an embodiment of the present utility model, the thickness of the pad protruding from the front surface of the solar cell is the same as the thickness of the front grid line.
[0013] In an embodiment of the present utility model, anti-breaking grid auxiliary lines are respectively arranged between two adjacent front main grids and between two adjacent back main grids.
[0014] The present utility model also provides a photovoltaic module, comprising:
[0015] A battery string formed by connecting a plurality of the solar cells through welding tapes;
[0016] An encapsulation layer covering the surface of the battery string;
[0017] A cover plate covering the surface of the encapsulation layer facing away from the battery string.
[0018] In an embodiment of the present utility model, the battery string comprises battery cell bodies alternately arranged at intervals of 0.3 - 0.6 mm in the first direction. Two adjacent battery cell bodies include a first battery cell and a second battery cell. Wherein, two ends of the welding tape are respectively welded to the pad of the first battery cell and the back main grid of the corresponding second battery cell.
[0019] In an embodiment of the present utility model, the thickness of the welding tape is less than 0.15 mm, and the width of the welding tape is not less than 2 mm.
[0020] In an embodiment of the present utility model, the encapsulation layer comprises a glue film, and the cover plate comprises a glass cover plate or a plastic cover plate.
[0021] The above technical solution of the present utility model has the following advantages compared with the prior art:
[0022] For the solar cell and the photovoltaic module of the present utility model, the solar cell adopts a design with gradually decreasing width of the front grid lines, which reduces the resistance loss during transmission, improves the current collection efficiency of the solar cell, reduces the usage amount of silver paste, and effectively reduces the cost.
[0023] The entire photovoltaic module adopts a multi-piece design, which reduces the in-series current, significantly reduces the internal loss, and the power can be increased by about 2.5%. The multi-piece structure design improves the overall load and anti-crack ability, and can be compatible with thinner crystalline silicon solar cells, which not only improves the performance of the module, but also enhances the mechanical strength and durability of the module. By welding the welding tapes to the pads on the front edge and the back main grids of adjacent solar cells respectively, there is no (less) occlusion on the front of each solar cell, which improves the power of the module. Description of the Drawings
[0024] To make the content of the present utility model easier to be clearly understood, the following further detailed description of the present utility model is given according to the specific embodiments of the present utility model and in conjunction with the attached drawings.
[0025] Figure 1 It is a schematic diagram of the connection between the solder ribbon of the present utility model and the pad on the front side of the solar cell.
[0026] Figure 2 It is a schematic diagram of the structure of the large-sized cell of the present utility model.
[0027] Figure 3 It is a partial schematic diagram of the structure of the large-sized cell of the present utility model.
[0028] Figure 4 It is a partial schematic diagram of the completion of the welding of the cell string of the present utility model.
[0029] Explanation of the reference numerals in the drawings of the specification:
[0030] 100, large-sized cell;
[0031] 1, cell body; 11, front grid line; 12, pad; 13, anti-breakage grid auxiliary line;
[0032] 2, solder ribbon;
[0033] 3, first cell;
[0034] 4, second cell. Specific embodiments
[0035] The following further description of the present utility model is given in conjunction with the attached drawings and specific embodiments, so that those skilled in the art can better understand the present utility model and be able to implement it, but the embodiments cited do not limit the present utility model.
[0036] In the present utility model, when directions (up, down, left, right, front and back) are described, it is only for the convenience of describing the technical solution of the present utility model, rather than indicating or implying that the technical features referred to must have a specific orientation, be constructed and operated in a specific orientation, so it cannot be understood as a limitation to the present utility model.
[0037] In the present utility model, the meaning of "several" is one or more, the meaning of "multiple" is two or more, and "greater than", "less than", "exceeding", etc. are understood as not including the present number; "above", "below", "within", etc. are understood as including the present number. In the description of the present utility model, if "first" and "second" are described, they are only for the purpose of distinguishing technical features and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity of the technical features indicated or the sequence relationship of the technical features indicated.
[0038] In the present utility model, unless otherwise clearly defined, terms such as "arranged", "installed", and "connected" should be understood in a broad sense. For example, they can be directly connected or indirectly connected through an intermediate medium; they can be fixedly connected, detachably connected, or integrally formed; they can be mechanically connected, electrically connected, or capable of communicating with each other; they can be the communication inside two components or the interaction relationship between two components. Those skilled in the art can reasonably determine the specific meanings of the above terms in the present utility model in combination with the specific content of the technical solution.
[0039] Referring to Figure 1 as shown, a solar cell includes:
[0040] a cell body 1;
[0041] a plurality of front grid lines 11 arranged at intervals along the first direction of the cell body 1 and extending along the second direction. Both ends of each front grid line 11 are respectively connected to pads 12 located at both ends of the cell body 1 along the second direction. The back surface of the cell body 1 is provided with back main grids corresponding to each of them. The first direction arrangement and the second direction are perpendicular to each other;
[0042] wherein, the width of the front grid line 11 gradually becomes smaller along the second direction.
[0043] It can be understood that the main function of the front grid line 11 is to collect and transmit electrons. The diffusion path of electrons in the cell is relatively long. Therefore, the existence of the grid line can effectively reduce the path length of electrons reaching the electrode, reduce the internal resistance, and improve the cell efficiency. Both ends of the front grid line 11 are connected to pads 12 located at both ends of the cell body 1 along the second direction for electrical connection and fixation.
[0044] Referring to Figure 2 and Figure 3 as shown, the cell body 1 is obtained by dividing a large-sized cell 100 into multiple sub-cells by a slicing machine. The large-sized cell includes a plurality of solar cells arranged along the second direction. Adjacent two solar cells are connected through pads 12 at one end edge of each of them.
[0045] And the front grid line 11 only needs to consider electrical performance transmission and does not need to consider welding performance. Therefore, silver paste with a lower silver content can be selected to reduce production costs. In addition, the width of the front grid line 11 gradually becomes smaller along the second direction, which can reduce the usage amount of silver paste. Silver paste is an expensive conductive material. Reducing its usage amount can significantly reduce production costs.
[0046] In one embodiment, the front grid line 11 is in an isosceles trapezoidal shape, and the width of the wide part of the front grid line 11 is 2±0.5mm, and the width of the narrow part is 0.8±0.2mm. This shape can optimize the current transmission path and reduce resistance loss. The width of the wide part of the front grid line 11 is 2±0.5mm, and the width of the narrow part is 0.8±0.2mm. This design not only ensures good electrical connection, but also reduces the amount of material used.
[0047] In one embodiment, the radial dimension of the pad 12 is not less than 3 mm. The larger pad 12 size ensures good welding strength and stability, and prevents the battery cell from breaking or falling off due to mechanical stress during use.
[0048] In one embodiment, the thickness of the pad 12 protruding from the front side of the solar cell is consistent with the thickness of the front grid line 11 .
[0049] In order to further improve the mechanical strength and durability of the cell, anti-break grid auxiliary lines 13 are respectively arranged between two adjacent front main grids and two adjacent back main grids. These auxiliary lines can effectively disperse mechanical stress, prevent grid line breakage, and improve the service life of the cell.
[0050] This embodiment also provides a photovoltaic module, including:
[0051] A battery string is formed by connecting a plurality of the solar cells mentioned above via a welding ribbon 2;
[0052] An encapsulation layer, covering the surface of the battery string;
[0053] A cover plate covers a surface of the packaging layer facing away from the battery string.
[0054] In one embodiment, referring to Figure 4 As shown, the battery string includes battery cell bodies 1 alternately arranged at intervals of 0.3 to 0.6 mm along the first direction, and two adjacent battery cell bodies 1 include a first battery cell 3 and a second battery cell 4, wherein the two ends of the welding strip 2 are respectively welded to the welding pad 12 of the first battery cell 3 and the corresponding back main grid of the second battery cell 4.
[0055] The welding strip 2 is respectively connected to the pad 12 at the front edge of the adjacent cell and the back main grid, so that the front of each cell is not blocked (less blocked), and the power of the module is improved. By reducing the cell spacing (0.3~0.6mm), the layout density of the cell is increased, the power generation of the photovoltaic module is improved, and more solar cells can be arranged in the same area, thereby increasing the amount of solar energy collected.
[0056] Specifically, the encapsulation layer covers the surface of the battery string, serving to protect the battery cells from environmental influences. The encapsulation layer can be made of various materials, such as polyvinyl butyral (PVB) film, ethylene-vinyl acetate copolymer (EVA) film, polyoctene copolymer (POE) film, or polyethylene terephthalate (PET) film, etc. These materials have good optical transparency and weather resistance, and can effectively protect the battery cells.
[0057] Specifically, the cover plate covers the surface of the encapsulation layer facing away from the battery string, and can be a cover plate with a light-transmitting function such as a glass cover plate or a plastic cover plate. Specifically, the surface of the cover plate facing the encapsulation layer can be an uneven surface, thereby increasing the utilization rate of incident light and improving the photoelectric conversion efficiency of the module.
[0058] In one embodiment, the solder ribbon 2 adopts a flat (wide and flat) structure, which is convenient for small-pitch welding. The thickness of the solder ribbon 2 is less than 0.15 mm, and the width of the solder ribbon 2 is not less than 2 mm. This enables the weight of the film to be reduced from 460 grams to 320 grams, and the usage amount of the solder ribbon 2 to be reduced by about 45%, and the usage amount of silver paste can be reduced.
[0059] The entire photovoltaic module through multi-piece design reduces the current within the string, significantly reduces internal losses, and the power can be increased by about 2.5%. The multi-piece structure design improves the overall load and anti-crack ability, and can be compatible with thinner crystalline silicon battery cells. This design not only improves the performance of the module, but also enhances the mechanical strength and durability of the module.
[0060] It can be understood that the production of a photovoltaic module includes the following steps: welding the battery string; laminating according to the structure of photovoltaic glass, film, battery string, film, photovoltaic glass or backsheet; using a laminator to tightly bond the raw materials of each layer together to form a whole; after lamination, trimming the edges of the module and performing appearance inspection to ensure there are no defects; installing the laminated photovoltaic module into an aluminum alloy frame to enhance its mechanical strength and facilitate subsequent installation and fixation; installing a junction box to provide an electrical connection interface for the installation and use of the photovoltaic module; performing a series of electrical performance and durability tests on the assembled photovoltaic module to ensure it meets the factory standards; packaging the tested qualified photovoltaic module.
[0061] Among them, the high-density battery string welding step:
[0062] Using a slicer, after dividing large-sized battery cells into multi-pieces, detecting and classifying the multi-piece battery cells;
[0063] Welding one end of the solder ribbon 2 to the edge pad 12 on the front of the first battery cell 3;
[0064] Placing the first battery cell 3 to ensure that the front of the first battery cell 3 faces upward;
[0065] Place the second solar cell 4, ensuring that the front side of the second solar cell 4 faces upward and the back side contacts the welding tape 2, and ensuring that the distance between the first solar cell 3 and the second solar cell 4 is between 0.3 - 0.6 mm;
[0066] Weld the main grid on the back side of the second solar cell 4 to the welding tape 2, ensuring that the back side of the second solar cell 4 is in a fully welded state;
[0067] And so on, weld the remaining solar cells.
[0068] The above settings not only improve the electrical connection quality between the solar cells, but also reduce the material usage and improve the production efficiency. By optimizing the welding process and material selection, the production cost of the photovoltaic module can be significantly reduced, while improving the performance and reliability of the module.
[0069] Finally, it should be noted that the above specific embodiments are only used to illustrate the technical solutions of the present invention rather than to limit them. Although the present invention has been described in detail with reference to the examples, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the spirit and scope of the technical solutions of the present invention, and they should all be covered within the scope of the claims of the present invention.
Claims
1. A solar cell, characterized in that: include: Battery cell body (1); A plurality of front grid lines (11) arranged at intervals along a first direction of the battery cell body (1) and extending along a second direction, the two ends of each of the front grid lines (11) being respectively connected to welding pads (12) located at two end edges of the battery cell body (1) in the second direction, the back side of the battery cell body (1) being provided with a back main grid corresponding to each of the front grid lines (11), the first direction being perpendicular to the second direction; Wherein, the width of the front grid line (11) gradually decreases along the second direction.
2. A solar cell according to claim 1, characterized in that: The front grid lines (11) are in the shape of an isosceles trapezoid.
3. A solar cell according to claim 1 or 2, characterized in that: The width of the front grid line (11) is 2±0.5 mm at its widest point, and 0.8±0.2 mm at its narrowest point.
4. A solar cell according to claim 1, characterized in that: The radial dimension of the welding pad (12) is not less than 3 mm.
5. The solar cell according to claim 1, characterized in that: The thickness of the solder pad (12) protruding from the front side of the battery cell is consistent with the thickness of the front side grid line (11).
6. The solar cell according to claim 1, characterized in that: Anti-break grid auxiliary lines (13) are respectively arranged between two adjacent front grid lines (11) and two adjacent back main grid lines.
7. A photovoltaic module, characterized in that: include: A battery string, formed by connecting a plurality of solar cells according to any one of claims 1 to 6 via a welding ribbon (2); An encapsulation layer, covering the surface of the battery string; A cover plate covers a surface of the packaging layer facing away from the battery string.
8. A photovoltaic module according to claim 7, characterized in that: The battery string comprises battery cell bodies (1) alternately arranged at intervals of 0.3 to 0.6 mm along the first direction, two adjacent battery cell bodies (1) comprising a first battery cell (3) and a second battery cell (4), wherein two ends of the welding ribbon (2) are respectively welded to the welding pad (12) of the first battery cell (3) and the corresponding back main grid of the second battery cell (4).
9. A photovoltaic module according to claim 7, characterized in that: The thickness of the welding strip (2) is less than 0.15 mm, and the width of the welding strip (2) is not less than 2 mm.
10. A photovoltaic module according to claim 7, characterized in that: The encapsulation layer includes an adhesive film, and the cover plate includes a glass cover plate or a plastic cover plate.