A photovoltaic cell, a grid plating method thereof, a photovoltaic module and a photovoltaic system

Abstract

The application discloses a photovoltaic cell and a grid line plating method thereof, a photovoltaic module and a photovoltaic system. The photovoltaic cell comprises a silicon cell. The surface of the silicon cell is a textured surface with a pyramid structure. The pyramid structure has a conductive grid which is formed by connecting metal grid lines arranged at the tip, edge and bottom of the pyramid structure. In the application, the metal grid lines are arranged at the tip, edge and bottom of the pyramid structure on the textured surface of the silicon cell, so that the metal grid lines are finally connected to form the conductive grid. The damage caused by laser opening to the silicon cell is reduced, the opening voltage loss of the silicon cell is smaller, and the working performance of the photovoltaic cell is improved.

Description

Technical Field

[0001] This invention relates to the field of photovoltaic cell technology, and in particular to a photovoltaic cell and its grid line plating method, a photovoltaic module and a photovoltaic system. Background Technology

[0002] Photovoltaic cell grid line fabrication mainly falls into two categories: electroplating and printing. High-efficiency cells such as TOPCon / HJT primarily use copper-plated grid lines. In the grid line fabrication process, the anti-reflective coating layer on the cell surface needs to be laser-grooved first, followed by the deposition of a seed layer in the grooved area, and then copper, silver, or tin plating, forming elliptical or flat grid lines with a width of approximately 10-30 μm and a height of approximately 5-20 μm. The disadvantage of this process is that the necessary laser grooving during grid line fabrication causes significant voltage loss in the cell, leading to a decrease in cell efficiency.

[0003] Therefore, minimizing the pressure loss during laser mold opening of solar cells is one of the important factors in improving the working efficiency of solar cells. Summary of the Invention

[0004] The purpose of this invention is to provide a photovoltaic cell and its grid line coating method, photovoltaic module and photovoltaic system, which can reduce laser damage caused by the coating of grid lines in the photovoltaic cell to a certain extent, reduce the opening voltage loss of the cell, and improve the working efficiency of the cell.

[0005] To address the aforementioned technical problems, in a first aspect, a photovoltaic cell is provided, comprising a silicon cell; the surface of the silicon cell is a textured surface with a pyramidal structure.

[0006] The pyramid structure has a conductive grid, which is formed by connecting metal grid lines at the tip, edges, and base of the pyramid structure.

[0007] This invention leverages the inherent pyramidal texture of the silicon solar cell surface. Only the tips, edges, and base of the pyramidal structure on the textured surface are molded and metal grid lines are installed, allowing these lines to connect and form a conductive mesh. Because the tips, edges, and base of the pyramidal structure converge laser energy, the laser energy used to form the grid lines at these locations can be relatively low. This results in less mold-making damage to the silicon solar cell, leading to lower opening pressure loss and improved photovoltaic cell performance.

[0008] In some embodiments, the conductive mesh covers several elongated regions with a width of 15µm to 200µm.

[0009] In some embodiments, the width of the metal gate line is 0.05µm to 1µm; the thickness is 50nm to 1µm.

[0010] In some embodiments, the metal gate line includes a seed layer, a conductive gate line layer, and an anti-oxidation layer stacked sequentially along the thickness direction;

[0011] The thickness ratio between the seed layer and the conductive gate layer is 0.02 to 6.

[0012] The thickness ratio between the conductive gate layer and the antioxidant layer is 0.25~10.

[0013] In some embodiments, the thickness of the seed layer is 10nm~300nm, the thickness of the conductive gate layer is 50nm~500nm, and the thickness of the antioxidant layer is 50nm~200nm.

[0014] In some embodiments, the metal grid line is a silver-plated line, and the thickness of the silver-plated line is 50nm~1um.

[0015] In some embodiments, a transparent dielectric layer is covered on the sloping surface of the pyramid structure; the transparent dielectric layer is an anti-reflection layer and a passivation layer, with a thickness of 10 nm to 200 nm.

[0016] The base dimension of the pyramid structure is 0.5um to 10um; and on the surface of the silicon solar cell, in a unit area of ​​100um×100um, the proportion of pyramid structures with a base dimension greater than 1.5um should be no less than 30%.

[0017] In some embodiments, the silicon solar cell is any one of TOPCon, PERC, HJT, or BC solar cells.

[0018] Secondly, a method for plating grid lines in a photovoltaic cell is provided, comprising:

[0019] A silicon solar cell with a textured surface formed by a pyramid structure is laser-irradiated to create a mold for a transparent dielectric layer covering the textured surface of the silicon solar cell, forming grooves extending along the tip, edge, and bottom of the pyramid structure; the transparent dielectric layer is the surface film layer of the silicon solar cell.

[0020] Metal grid lines are plated in the grooves on the silicon solar cell to form a conductive mesh.

[0021] In the process of preparing silicon solar cells, this invention involves laser irradiation to create grooves on the pointed, edge, and bottom portions of the pyramid structure on the front side of the silicon solar cell. This allows for the creation of molds on the pointed, edge, and bottom portions of the pyramid structure with relatively low laser beam power, and the deposition of metal grid lines to form a conductive mesh. This reduces the damage caused by grooving to the silicon solar cell, resulting in a silicon solar cell with lower opening voltage loss, which is beneficial for improving the working performance of photovoltaic solar cells.

[0022] In some embodiments, a silicon solar cell with a textured surface formed by a pyramid structure is laser-irradiated to mold a transparent dielectric layer covering the textured surface of the silicon solar cell, forming grooves extending along the tip, edge, and bottom of the pyramid structure, including:

[0023] The laser power is pre-calibrated based on the thickness of the transparent dielectric layer covering the silicon solar cell to obtain a calibration power; wherein the calibration power is not greater than the minimum mold opening power corresponding to the current thickness of the transparent dielectric layer;

[0024] According to the specified power, the silicon solar cell is irradiated with a laser to perform photolithography on the transparent dielectric layer at the tip, edge, and bottom of the pyramid structure to form grooves.

[0025] In some embodiments, the silicon solar cell is laser-irradiated according to the rated power to perform photolithography on the transparent dielectric layer at the tip, edge, and bottom of the pyramid structure to form grooves, including:

[0026] According to the calibrated power, any one of the following laser beams with a wavelength of 266nm~1550nm (picosecond laser beam, femtosecond laser beam, or flat laser beam) is used to perform photolithography on the transparent dielectric layer on the silicon solar cell to form the groove with a width of 0.05um~1um; wherein the spot size of the laser beam is 10um~200um.

[0027] In some embodiments, the process of pre-determining the calibration power includes:

[0028] The surface of the silicon battery sample with the same structural material as the silicon battery cell is polished to form a polished surface;

[0029] A transparent dielectric sampling layer is formed on the polished surface; wherein the transparent dielectric sampling layer is a film layer with the same material and thickness as the transparent dielectric layer on the silicon solar cell.

[0030] The transparent dielectric sampling layer on the silicon solar cell sample is irradiated sequentially with laser beams of different powers to obtain the minimum grooving power for grooving the transparent dielectric sampling layer;

[0031] The calibration power is a power that is not greater than the minimum slotting power.

[0032] Thirdly, a photovoltaic module is provided, comprising a front cover plate, a first encapsulating film, a battery string layer, a second encapsulating film, and a back cover plate stacked sequentially.

[0033] The battery string layer includes a plurality of photovoltaic cells as described in any of the above descriptions.

[0034] In the photovoltaic module of the present invention, the photovoltaic cells with conductive grids formed in the cell string layer have lower on-state voltage loss, which is beneficial to improving the working performance of the photovoltaic module.

[0035] Fourthly, a photovoltaic system is provided, including the photovoltaic module as described above.

[0036] In the photovoltaic system of the present invention, the photovoltaic cells in the photovoltaic module have lower opening voltage loss, thereby improving the working performance of the photovoltaic module and improving the overall working performance and economic benefits of the photovoltaic system. Attached Figure Description

[0037] To more clearly illustrate the technical solutions of the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0038] Figure 1 A partial structural schematic diagram of a silicon solar cell with a pyramidal textured surface provided in an embodiment of the present invention;

[0039] Figure 2 A schematic diagram illustrating the principle of laser mold opening provided in an embodiment of the present invention;

[0040] Figure 3 A schematic diagram showing a comparison of partial cross-sectional structures of a photovoltaic cell before and after mold opening, provided in an embodiment of the present invention;

[0041] Figure 4 A schematic flowchart illustrating a method for plating grid lines in a photovoltaic cell according to an embodiment of the present invention;

[0042] Figure 5 This is a schematic diagram of the exploded structure of a photovoltaic module provided in an embodiment of the present invention;

[0043] Figure 6 This is a schematic diagram of the frame structure of a photovoltaic system provided in an embodiment of the present invention;

[0044] The accompanying drawings are not drawn to scale.

[0045] Reference numerals: 1 for silicon solar cell, 10 for transparent dielectric layer, 101 for wire groove, 2 for pyramid structure, 21 for tip, 22 for edge, 23 for bottom, 24 for slope, 3 for metal grid line; 100 for front cover plate, 200 for first encapsulation film, 300 for cell string layer, 400 for second encapsulation film, 500 for back cover plate, 600 for frame, 700 for junction box, 1000 for photovoltaic system, 1001 for photovoltaic module. Detailed Implementation

[0046] The descriptions of specific structures or functions implemented according to the inventive concept disclosed in this specification are merely illustrative examples for explaining embodiments of the inventive concept. Those skilled in the art will understand that embodiments of the inventive concept can have various variations and forms, and are not limited to the embodiments described in this specification, but also include various modifications, equivalents, or substitutions made within the scope of the inventive purpose, concept, and technology.

[0047] The researchers of this invention have discovered that in the traditional manufacturing process of photovoltaic cells, it is necessary to perform laser molding on the surface of the photovoltaic cell and then form grid lines in the laser-molded area. However, laser grooving on the surface of the photovoltaic cell will damage the structure of the photovoltaic cell, thereby forming composite centers, which will affect the power generation efficiency of the photovoltaic cell in the actual power generation process to a certain extent.

[0048] Based on this, the present invention provides a photovoltaic cell and a method for plating its grid lines, which can reduce the pressure loss caused by laser mold opening to a certain extent and improve the working power of the photovoltaic cell.

[0049] To enable those skilled in the art to better understand the present invention, the invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. Obviously, the described embodiments are merely some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0050] like Figures 1 to 3 As shown, Figure 1 This is a partial structural diagram of a silicon solar cell with a pyramidal textured surface, provided in an embodiment of the present invention. Figure 2 A schematic diagram illustrating the principle of laser mold opening provided in an embodiment of the present invention; Figure 3This is a schematic diagram comparing the partial cross-sectional structure of the photovoltaic cell before and after mold opening, as provided in an embodiment of the present invention.

[0051] In one specific embodiment of the present invention, the photovoltaic cell may include:

[0052] Silicon solar cell 1; the surface of silicon solar cell 1 is a textured surface with a pyramid structure 2;

[0053] A transparent medium layer 10 is covered on the sloping surface 24 of the pyramid structure 2;

[0054] Metal grid lines 3 are sequentially connected and extended at the tip 21, edge 22, and base 23 of the pyramid structure 2; the metal grid lines 3 are sequentially connected to form a conductive grid.

[0055] like Figure 1 and Figure 2 As shown, before the metal grid lines 3 are formed on the silicon solar cell 1, its textured surface is covered with a transparent dielectric layer 10. The transparent dielectric layer 10 can specifically be an anti-reflection layer and a passivation layer, and its thickness can be 10nm~200nm. For example, the transparent dielectric layer 10 can be a combination of one or more of the following films: aluminum oxide film, silicon nitride film, silicon oxide film, silicon oxynitride film, magnesium fluoride film, ITO film, FTO film, and TCO film.

[0056] Before the actual deposition of the metal grid lines 3, the transparent dielectric layer 10 needs to be laser-cut to expose the PN junction on the silicon solar cell 1, and then the metal grid lines 3 that are electrically connected to the PN junction are deposited.

[0057] It is understandable that, such as Figure 1 As shown, under normal circumstances, a textured surface with a large number of pyramid structures 2 (that is, roughly square pyramidal pointed structures) will be formed on the front side of the silicon solar cell 1; the base size of each pyramid structure 2 is approximately 0.5um to 10um; and on the surface of the silicon solar cell 1, in a unit area of ​​100um×100um, the proportion of pyramid structures 2 with a base greater than 1.5um should not be less than 30%.

[0058] Therefore, in this embodiment, during the molding process of the transparent dielectric layer 10 on the front side of the silicon solar cell 1, the characteristic of its surface having a pyramid structure 2 can be fully utilized, and the transparent dielectric layer 10 of the pyramid structure 2 is only molded on the tip 21, edge 22 and bottom edge 23.

[0059] like Figure 2 As shown, Figure 2The diagram shows the optical path of the apex of a pyramid structure 2 and the common base 23 between two adjacent pyramid structures 2. When parallel laser beams irradiate the surface of the silicon solar cell 1 perpendicularly, the light converges at the apex of the pyramid structure 2 due to the refraction of light by the transparent dielectric layer 10, resulting in higher laser energy at the apex 21. Similarly, energy convergence occurs at the edges 22 of the pyramid structure 2. A valley is formed at the common base 23 of two adjacent pyramid structures 2. Laser light incident on this valley undergoes not only refraction but also repeated reflections. The repeatedly reflected laser light ultimately propagates at the valley, meaning that the valley also absorbs more laser energy.

[0060] Based on this, in this embodiment, when a laser beam is irradiated onto the textured surface of the silicon solar cell 1 with a pyramid structure 2, the tip 21, edge 22, and base 23 of the pyramid structure 2 will converge and absorb more laser energy. By reasonably controlling the power of the laser beam irradiating the surface of the silicon solar cell 1, the power of the laser beam is not sufficient to etch the transparent dielectric layer 10 on the pyramid slope 24. However, due to the convergence and reflection of laser energy at the tip 21, edge 22, and base 23 of the pyramid structure 2, the absorbed laser energy can etch and remove the transparent dielectric layer 10. That is, only the transparent dielectric layer 10 at the tip 21, edge 22, and base 23 of the pyramid structure 2 is etched and removed. Figure 3 As shown.

[0061] Based on the above discussion, since this invention only requires molding the transparent dielectric layer 10 of the tip 21, edge 22, and bottom 23 of the pyramid structure 2 to form metal grid lines 3, a lower power laser beam can be used, resulting in less opening voltage loss in the silicon solar cell 1. Furthermore, since the molding positions are the tip 21, edge 22, and bottom 23 of the pyramid structure 2, the molding positions can be distributed in a mesh pattern. Based on the formation of finer metal grid lines 3 at the slotted positions, a mesh-interconnected conductive grid is formed. This ensures current convergence output and reduces the reflectivity of the grid lines to the light incident on the photovoltaic cell, thereby further increasing the photoelectric conversion efficiency of the photovoltaic cell.

[0062] Optionally, in this embodiment, the area on the silicon solar cell 1 where a conductive grid is formed by metallization can be several elongated areas, similar to the area covered by several grid lines on a conventional solar cell; the width of each elongated area can be 15um to 200um, and the length should be the same as the side length of the silicon solar cell 1.

[0063] In another optional embodiment of the present invention, metal grid lines 3 can also be formed on the tip 21, edge 22 and bottom edge 23 of all pyramid structures 2 on the entire front side of the silicon solar cell 1, so that the conductive grid covers the entire front area of ​​the silicon solar cell 1.

[0064] Furthermore, the width of each metal gate line 3 can be 0.05µm to 1µm, and the thickness can be 50nm to 1µm. The length of each metal gate line is determined by the edge length and base length of the pyramid structure 2 in which it is located.

[0065] Optionally, each metal gate line 3 may comprise a seed layer, a conductive gate line layer, and an anti-oxidation layer stacked sequentially; wherein the thickness ratio between the seed layer and the conductive gate line layer is 0.02~6; and the thickness ratio between the conductive gate line layer and the anti-oxidation layer is 0.25~10.

[0066] Further optionally, the seed layer has a thickness of 10 nm to 300 nm, the conductive grid layer has a thickness of 50 nm to 500 nm, and the anti-oxidation layer has a thickness of 50 nm to 200 nm. Additionally, for some solar cells requiring finer grid lines, the metal grid line 3 can also be a silver-plated line, with a thickness of 50 nm to 1 μm.

[0067] Furthermore, the silicon solar cell used in this invention can be any one of TOPCon solar cells, PERC solar cells, HJT solar cells, or BC solar cells, and there are no specific limitations on this in this invention.

[0068] In summary, this invention leverages the inherent pyramidal texture of the silicon solar cell surface. Only the transparent dielectric layer at the tips, edges, and base of the pyramidal structure on the textured surface of the silicon solar cell is molded and metal grid lines are installed, allowing these metal grid lines to connect and form a conductive mesh. Because the tips, edges, and base of the pyramidal structure have a converging effect on laser energy, the laser energy used in forming the grid lines at these locations can be relatively small. This results in less mold-making damage to the silicon solar cell itself, leading to a silicon solar cell with lower opening pressure loss, which is beneficial for improving the performance of the photovoltaic cell.

[0069] Reference Figures 1 to 4 As shown, Figure 4 This is a schematic flowchart of a method for plating grid lines in a photovoltaic cell, provided in an embodiment of the present invention.

[0070] In one specific embodiment of the present invention, the method for plating the grid lines of the photovoltaic cell may include:

[0071] S1: Laser irradiation is performed on the silicon solar cell 1 with a textured surface formed by the pyramid structure 2 to open the textured surface covering the silicon solar cell 1 and form a groove 101 extending along the tip 21, edge 22 and bottom edge 23 of the pyramid structure 2.

[0072] S2: Metal grid lines 3 are plated in the grooves 101 on the silicon solar cell 1 to form a conductive grid.

[0073] like Figure 1 As shown, during the fabrication of silicon solar cell 1, a textured surface with numerous pyramidal structures 2 (i.e., roughly square pyramidal apical structures) is normally formed on the front side of silicon solar cell 1. Figure 2 As shown, at the tip 21, edge 22, and base 23 of the pyramid structure 2, the laser beams refracting light through the transparent dielectric layer 10 converge, thus absorbing more laser energy. Based on this, in this embodiment, the power of the laser beam irradiating the surface of the silicon cell 1 can be reasonably controlled so that the power of the laser beam is insufficient to etch the transparent dielectric layer 10 on the pyramid slope 24. However, at the tip 21, edge 22, and base 23 of the pyramid structure 2, due to the convergence and reflection of laser energy, the absorbed laser energy can etch away the transparent dielectric layer 10. This means that only the transparent dielectric layer 10 at the tip 21, edge 22, and base 23 of the pyramid structure 2 is etched away. Figure 3 As shown.

[0074] Further optionally, the process of molding the transparent dielectric layer 10 on the silicon solar cell 1 may also include:

[0075] S10: The laser power is calibrated in advance based on the thickness of the transparent dielectric layer 10 covering the silicon solar cell 1 to obtain the calibration power; wherein, the calibration power is not greater than the minimum mold opening power corresponding to the current thickness of the transparent dielectric layer 10;

[0076] S11: The silicon solar cell 1 is irradiated with laser according to the rated power to perform photolithography on the transparent dielectric layer 10 of the tip 21, edge 22 and bottom 23 of the pyramid structure 2 to form a groove 101.

[0077] As described above, in this embodiment, during the photolithographic molding process of the transparent dielectric layer 10 on the silicon solar cell 1, only the tip 21, edge 22, and base 23 of the pyramid structure 2 are photolithographically molded, while the transparent dielectric layer 10 on the slope 24 of the pyramid structure 2 is not photolithographically removed. Therefore, it is necessary to reasonably control the energy of the laser beam to ensure that the energy converged at the tip 21 and edge 22, and the energy repeatedly reflected at the base 23, is sufficient to photolithographically remove the transparent dielectric layer 10, while the laser energy on the slope 24 of the pyramid structure 2 is insufficient to photolithographically remove the transparent dielectric layer 10. Clearly, this reasonable laser power should be less than the minimum molding power required to photolithographically remove the transparent dielectric layer 10 of the current thickness on the silicon solar cell 1.

[0078] In practical applications, the minimum mold opening power corresponding to the current thickness of the transparent dielectric layer 10 can be determined through preliminary experiments. Then, based on this minimum mold opening power, the calibration power that can perform photolithographic mold opening on the tip 21, edge 22 and bottom edge 23 of the pyramid structure 2 can be determined.

[0079] Further, optionally, the process of pre-determining the calibration power may include:

[0080] S101: Polish the surface of the silicon cell sample with the same structural material as silicon cell 1 to form a polished surface;

[0081] S102: A transparent dielectric sampling layer is formed on the polished surface; wherein the transparent dielectric sampling layer is a film layer with the same material and thickness as the transparent dielectric layer 10 on the silicon solar cell 1;

[0082] S103: The transparent dielectric sampling layer on the silicon cell sample is irradiated sequentially with laser beams of different powers to obtain the minimum grooving power for grooving the transparent dielectric sampling layer;

[0083] S104: The calibration power is a power that is not greater than the minimum slotting power.

[0084] In this embodiment, the silicon solar cell sample and the silicon solar cell 1 that requires laser molding should have the same structure; the difference is that the front side of the silicon solar cell sample is polished and then a transparent dielectric sampling layer is deposited, and the thickness and film composition of the transparent dielectric sampling layer on the silicon solar cell sample and the transparent dielectric layer 10 on the silicon solar cell 1 are the same.

[0085] It is understood that the minimum grooving power determined in this embodiment can essentially be regarded as the minimum grooving power for molding the transparent dielectric layer 10 on the slope surface 24 of the pyramid structure 2. Obviously, the slope surface 24 of the pyramid structure 2 is a roughly flat surface. Therefore, in the process of determining the minimum grooving power for grooving the transparent dielectric layer 10 on the silicon cell sample, the front side of the silicon cell sample can be directly processed to form a polished surface, thereby forming a surface shape that is closer to the transparent dielectric layer 10 on the slope surface 24 of the pyramid structure 2, thus making it simpler and more accurate to determine the minimum grooving power.

[0086] During the minimum grooving power calibration process, laser beams of different powers can be used sequentially to mark and test silicon solar cell samples with a specific overlap rate (such as 0~80%). The results can be observed under an electron microscope to find the minimum laser power that can be etched and molded for the transparent dielectric sampling layer of the current thickness under the current wavelength laser beam, which is also the minimum grooving power.

[0087] Therefore, the minimum grooving power is the upper limit of the laser power for irradiating the silicon solar cell 1. In practical applications, in order to avoid the transparent dielectric layer 10 on the slope surface 24 of the pyramid structure 2 being irradiated and etched by the laser, a laser power slightly less than the minimum grooving power can be selected as the calibration power. Considering that the laser beam is generally obliquely incident on the slope surface 24 of the pyramid structure 2, under normal circumstances, the calibration power of the laser beam is equal to the minimum laser power, which is not enough to etch and remove the transparent dielectric layer 10 on the slope surface 24 of the pyramid structure 2.

[0088] Based on the above discussion, after determining the calibration power, laser beam lithography can be performed on the silicon solar cell 1 according to the calibration test, using that calibration power. Optionally, the laser beam in this embodiment can be any one of a picosecond laser beam, femtosecond laser beam, or flat laser beam with a wavelength of 266nm~1550nm. A groove 101 with a width of 0.05um~1um is formed at the tip 21, edge 22, and bottom edge 23 of the pyramid structure 2. The laser spot size formed on the silicon solar cell 1 by the laser beam is 10um~200um. It can be understood that if the laser spot in this embodiment is circular, the diameter of the circular spot is 10um~200um; if the laser spot is rectangular, the size of the rectangular spot along the direction perpendicular to the movement of the laser spot on the silicon solar cell 1 is 10um~200um.

[0089] Based on any of the above embodiments, after completing the photolithographic mold opening of the transparent dielectric layer 10 at a specific location on the silicon solar cell 1, metal grid lines 3 can be further deposited on the silicon solar cell 1 at the mold opening location; such as Figure 1 and Figure 3As shown, Figure 1 The image shows metal grid lines 3 extending from the tip 21, edge 22, and base 23 of a portion of the pyramid structure 2. Figure 3 The cross-section shows a schematic diagram of photolithographic grooves 101 on the transparent dielectric layer 10, and metal gate lines 3 formed in the grooves 101.

[0090] In an optional embodiment of the present invention, the process of plating the metal grid wires 3 in the wire groove 101 may include:

[0091] S21: Nickel is plated at the slotted positions on the silicon solar cell to form a seed layer of 10nm~300nm;

[0092] S22: Copper is plated on the seed layer to form a conductive gate layer of 50nm~500nm;

[0093] S23: Silver or tin is plated on the conductive gate layer to form an antioxidant layer of 50nm~200nm.

[0094] It should be noted that the seed layer, conductive gate layer, and antioxidant layer in this embodiment can all be formed by electroplating or chemical plating.

[0095] Furthermore, in another optional embodiment of the present invention, the metal grid line 3 may also be silver plated directly on the slotted position of the silicon cell 1 to form a finer silver metal grid line 3 forming a conductive mesh.

[0096] like Figure 5 As shown, the present invention also provides an embodiment of a photovoltaic module, which may include:

[0097] The front cover plate 100, the first encapsulating film 200, the battery string layer 300, the second encapsulating film 400 and the back cover plate 500 are stacked in sequence.

[0098] The battery string layer 300 includes a plurality of photovoltaic cells as described in any of the above.

[0099] A photovoltaic (PV) module is a device that directly converts light energy into electrical energy through the photoelectric effect or photochemical effect. A PV module typically has a stacked encapsulation structure, comprising at least the following from the light-facing side to the backlighting side: a front cover plate 100, a first encapsulating film 200, a cell string layer 300, a second encapsulating film 400, and a back cover plate 500, as well as a frame surrounding the stacked structure and a junction box located on one side of the back cover plate 500.

[0100] The front cover 100 may be made of a material with excellent light transmittance, impact resistance, corrosion resistance, and weather resistance, and may optionally include at least one of the following materials: tempered glass, plexiglass, transparent ceramics, organic fibers, or polymers. In some embodiments, the front cover 100 may include at least one of an insulating barrier layer, a fluorinated weather-resistant layer, and a transition adhesive layer.

[0101] The back cover 500 typically needs to possess insulation, water resistance, aging resistance, weather resistance, and corrosion resistance. It may optionally include at least one of tempered glass, acrylic glass, metal back cover 500, or composite back cover 500 with PET film as the substrate. The PET-based composite back cover 500 may, depending on the needs of different scenarios, include various types such as composite (e.g., TPT / KPK, TPE / KPE), coated (e.g., TPC, KPC, CPC), and co-extruded (e.g., PO).

[0102] It is understandable that the material selection of the front cover 100 and the back cover 500 does not affect each other, and the same or different materials can be selected according to different application scenarios of the components (such as residential photovoltaics and building-integrated photovoltaics).

[0103] The first encapsulating film 200 and the second encapsulating film 400 may be selected from at least one of ethylene-vinyl acetate copolymer (EVA) film, polyvinyl octene coelastomer (POE) film, EVA-POE-EVA co-extruded film (EPE), PVB (polyvinyl butyral), polyethylene terephthalate (PET) film, or liquid silicone. In some embodiments, the first encapsulating film 200 and the second encapsulating film 400 may further include one or more functional additives selected from the group consisting of crosslinking agents, coupling agents, antioxidants, ultraviolet absorbers, etc., to improve the crosslinking degree, weather resistance, adhesive strength, and anti-aging properties of the film. It is understood that the first encapsulating film 200 and the second encapsulating film 400 may be made of the same or different materials.

[0104] The battery string layer 300 includes multiple battery strings, which can be combined in series, parallel, or series-parallel configurations to achieve current collection and output. Further, each battery string is formed by sequentially connecting multiple battery cells via connectors. In some embodiments, at least a portion of the connector is electrically connected to the back electrode of one battery cell, and at least another portion of the connector is electrically connected to the front or back electrode of another battery cell to form a battery string. The connector may optionally include conductive elements such as solder strips, busbars, or metal clips. In some embodiments, to improve welding performance, oxidation resistance, and weather resistance, the connector material may preferably be a highly conductive metal material, such as at least one of silver, copper, tin, and nickel, or an alloy thereof. In some embodiments, to balance conductivity and cost control, the connector material may also be at least one of metal-clad composite materials such as silver-coated copper, copper-coated silver, copper-coated aluminum, aluminum-coated copper, tin-plated copper, or nickel-plated copper. The electrical connection may be selected from one of the following methods: laser welding, spot welding, bonding, ultrasonic welding, resistance welding, or brazing.

[0105] A photovoltaic cell may include a semiconductor substrate, a first emitter of a first conductivity type, and a second emitter of a second conductivity type. It is understood that one of the first and second conductivity types is P-type, and the other is N-type. The semiconductor substrate may include an N-type silicon substrate or a P-type silicon substrate. N-type silicon substrates are typically formed by doping with Group V elements such as phosphorus, arsenic, or antimony, and have the characteristic that the majority carriers are electrons; P-type silicon substrates are typically formed by doping with Group III elements such as boron, gallium, or aluminum, and have the characteristic that the majority carriers are holes.

[0106] A conductive grid is provided on the photovoltaic cell as a grid line to collect the output current; the material forming the conductive grid can be at least one of silver-based conductive paste or silver-coated copper composite paste. The paste uses highly conductive metal powder as the conductive substrate, and the substrate can be at least one of silver powder, copper powder, or silver-coated copper composite powder; to improve the ohmic contact performance, conductivity, and long-term weather resistance of the electrodes, a composite functional layer can be provided on the surface of the substrate or in the grid line structure, and the functional layer material includes at least one of glass powder, organic carrier, nickel-based barrier layer, tin-based alloy layer, or anti-oxidation and corrosion-resistant coating.

[0107] It is understood that the photovoltaic cell can be at least one of the following commonly used in the field: TOPCon (Tunnel Oxide Passivated Contact) cell, HJT (Heterojunction with Intrinsic Thin-film) cell, BC (Back Contact) cell, perovskite / tandem cell, etc.

[0108] The frame 600 surrounds the periphery of the stacked structure and is typically made of aluminum alloy or steel alloy. In some embodiments, the frame 600 may also be a fiberglass frame or a plastic frame. The inner side of the frame 600 usually has grooves for filling with sealant to achieve a sealed bond with the stacked components formed by the front cover 100, the first encapsulating film 200, the battery string layer 300, the second encapsulating film 400, and the back cover 500, thereby blocking moisture and buffering external impacts. In some embodiments, the frame 600 can be assembled using corner brackets.

[0109] A junction box 700 is located on one side of the back cover 500 and is electrically connected to the terminals of the bus electrodes in the battery string layer 300 via a lead-out busbar for energy extraction. The junction box 700 typically includes a housing and cover made of weather-resistant insulating material, conductive connecting tabs disposed within the housing, and one or more bypass diodes. The bypass diodes are connected in parallel with sub-units of the battery string. The electrical leads of the junction box 700 include photovoltaic-specific connectors and cables. The cables preferably use cross-linked polyethylene insulating sheaths and tinned copper core wires. In some embodiments, the interior of the junction box 700 may also be filled and encapsulated with potting compound to achieve insulation, thermal conductivity, moisture protection, and fixation.

[0110] like Figure 6 As shown, the present invention also provides an embodiment of a photovoltaic system 1000, which may include the photovoltaic module 1001 as described above.

[0111] The photovoltaic system 1000 provided by this invention can be applied in photovoltaic power plants, such as ground power plants, rooftop power plants, and water surface power plants. It can also be applied to equipment or devices that use solar energy to generate electricity, such as user solar power supplies, solar street lights, solar cars, solar buildings, etc.

[0112] It is understandable that the application scenarios of the PV system 1000 are not limited to this; that is to say, the PV system 1000 can be applied in all fields that require solar power generation. Taking a PV power generation system as an example, the PV system 1000 may include a PV array, a combiner box, and an inverter. The PV array may be an array combination of multiple PV modules. For example, multiple PV modules can form multiple PV arrays. The PV array is connected to the combiner box, which can collect the current generated by the PV 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 realize solar power supply.

[0113] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that the elements inherent in a process, method, article, or apparatus that includes a list of elements are included. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element. Additionally, portions of the technical solutions provided in the embodiments of the present invention that are consistent with the implementation principles of corresponding technical solutions in the prior art have not been described in detail to avoid excessive elaboration.

[0114] This article uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. It should be noted that those skilled in the art can make several improvements and modifications to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the protection scope of the present invention.

Claims

1. A photovoltaic cell, characterized in that, Includes silicon solar cells; the surface of the silicon solar cells is a textured surface with a pyramid structure; a transparent dielectric layer is covered on the sloping surface of the pyramid structure; The pyramid structure has a conductive grid, which is formed by connecting metal grid lines at the tip, edges, and bottom of the pyramid structure. The metal grid lines are formed by molding the transparent dielectric layer at the tip, edges, and bottom of the pyramid structure and creating grooves.

2. The photovoltaic cell as described in claim 1, characterized in that, The conductive mesh covers several elongated areas with a width of 15µm to 200µm.

3. The photovoltaic cell as described in claim 1, characterized in that, The width of the metal gate line is 0.05um to 1um, and the thickness is 50nm to 1um.

4. The photovoltaic cell as described in claim 1, characterized in that, The metal gate line includes a seed layer, a conductive gate line layer, and an anti-oxidation layer stacked sequentially along the thickness direction; The thickness ratio between the seed layer and the conductive gate layer is 0.02 to 6. The thickness ratio between the conductive gate layer and the antioxidant layer is 0.25~10.

5. The photovoltaic cell as described in claim 4, characterized in that, The thickness of the seed layer is 10nm~300nm, the thickness of the conductive gate layer is 50nm~500nm, and the thickness of the antioxidant layer is 50nm~200nm.

6. The photovoltaic cell as described in claim 1, characterized in that, The metal grid lines are silver-plated lines, and the thickness of the silver-plated lines is 50nm~1um.

7. The photovoltaic cell as described in claim 1, characterized in that, The transparent dielectric layer is an anti-reflection layer and a passivation layer, with a thickness of 10nm~200nm; The base dimension of the pyramid structure is 0.5um to 10um; and on the surface of the silicon solar cell, in a unit area of ​​100um×100um, the proportion of pyramid structures with a base dimension greater than 1.5um should be no less than 30%.

8. The photovoltaic cell as described in claim 1, characterized in that, The silicon solar cell is any one of TOPCon, PERC, HJT, or BC solar cells.

9. A method for plating grid lines in a photovoltaic cell, characterized in that, include: A silicon solar cell with a textured surface formed by a pyramid structure is laser-irradiated to mold a transparent dielectric layer covering the tip, edge, and bottom of the pyramid structure in the textured surface of the silicon solar cell, forming grooves extending along the tip, edge, and bottom of the pyramid structure; the transparent dielectric layer is the surface film layer of the silicon solar cell. Metal grid lines are plated in the grooves on the silicon solar cell to form a conductive mesh.

10. The method for plating grid lines in a photovoltaic cell as described in claim 9, characterized in that, Laser irradiation is applied to a silicon solar cell with a textured surface forming a pyramid structure to create a molded transparent dielectric layer covering the pointed, edge, and base portions of the pyramid structure within the textured surface of the silicon solar cell. This molded layer forms grooves extending along the pointed, edge, and base portions of the pyramid structure, including: The laser power is pre-calibrated based on the thickness of the transparent dielectric layer covering the silicon solar cell to obtain the calibration power; wherein the calibration power is not greater than the minimum mold opening power corresponding to the current thickness of the transparent dielectric layer; According to the specified power, the silicon solar cell is irradiated with a laser to perform photolithography on the transparent dielectric layer at the tip, edge, and bottom of the pyramid structure to form grooves.

11. The method for plating grid lines of a photovoltaic cell as described in claim 10, characterized in that, According to the specified power, the silicon solar cell is subjected to laser irradiation to perform photolithography on the transparent dielectric layer at the tip, edge, and base of the pyramid structure to form grooves, including: According to the calibrated power, any one of the following laser beams with a wavelength of 266nm~1550nm (picosecond laser beam, femtosecond laser beam, or flat laser beam) is used to perform photolithography on the transparent dielectric layer on the silicon solar cell to form the groove with a width of 0.05um~1um; wherein the spot size of the laser beam is 10um~200um.

12. The method for plating grid lines in a photovoltaic cell as described in claim 10, characterized in that, The process of pre-determining the calibration power includes: The surface of the silicon battery sample with the same structural material as the silicon battery cell is polished to form a polished surface; A transparent dielectric sampling layer is formed on the polished surface; wherein the transparent dielectric sampling layer is a film layer with the same material and thickness as the transparent dielectric layer on the silicon solar cell. The transparent dielectric sampling layer on the silicon solar cell sample is irradiated sequentially with laser beams of different powers to obtain the minimum grooving power for grooving the transparent dielectric sampling layer; The calibration power is a power that is not greater than the minimum slotting power.

13. A photovoltaic module, characterized in that, It includes a front cover, a first encapsulating film, a battery string layer, a second encapsulating film, and a back cover, which are stacked sequentially. The battery string layer includes a plurality of photovoltaic cells as described in any one of claims 1 to 8.

14. A photovoltaic system, characterized in that, Including the photovoltaic module as described in claim 13.

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