Method for producing a photovoltaic module

Abstract

This application discloses a method for manufacturing a photovoltaic module. The photovoltaic module includes a solar cell, a first pre-crosslinked film, a second pre-crosslinked film, a front glass, a back pre-crosslinked film, a back adhesive film, and a backsheet or back glass. The first pre-crosslinked film is attached to the front of the solar cell, the second pre-crosslinked film is attached to the side of the first pre-crosslinked film facing away from the solar cell, the front glass is attached to the side of the second pre-crosslinked film facing away from the first pre-crosslinked film, the back pre-crosslinked film is attached to the back of the solar cell, the back adhesive film is attached to the side of the back pre-crosslinked film facing away from the solar cell, and the backsheet or back glass is attached to the side of the back adhesive film facing away from the back pre-crosslinked film. By attaching the first pre-crosslinked film to the front of the solar cell and then attaching the second pre-crosslinked film to the side of the first pre-crosslinked film facing away from the solar cell, this application creates a pre-crosslinking gradient between the first and second pre-crosslinked films, thereby effectively improving the reliability of the photovoltaic module.

Description

Technical Field

[0001] This application relates to the field of solar cell technology, specifically to a photovoltaic module and a method for producing a photovoltaic module. Background Technology

[0002] In the manufacturing and application of busbarless solar cells, the coating of busbarless solar cells has a pre-crosslinking degree. If conventional encapsulation films are used during encapsulation, the difference in the pre-crosslinking degree between the two types of encapsulation films may lead to a decrease in the reliability of the corresponding photovoltaic modules. Summary of the Invention

[0003] In order to overcome the problems existing in the prior art, the main objective of this application is to provide a photovoltaic module and a method for producing photovoltaic modules that can improve reliability.

[0004] To achieve the above objectives, this application specifically adopts the following technical solution:

[0005] This application provides a photovoltaic module, the photovoltaic module comprising:

[0006] Battery cells;

[0007] A first pre-crosslinked film is attached to the front side of the battery cell;

[0008] The second pre-crosslinked film is attached to the side of the first pre-crosslinked film facing away from the battery cell;

[0009] The front glass is attached to the side of the second pre-crosslinked film facing away from the first pre-crosslinked film;

[0010] A back pre-crosslinked film is attached to the back of the battery cell;

[0011] A back adhesive film is attached to the side of the back pre-crosslinked film facing away from the battery cell.

[0012] A back panel or back glass, wherein the back panel or back glass is attached to the side of the back adhesive film facing away from the back pre-crosslinked film.

[0013] In this embodiment, by attaching a first pre-crosslinked film to the front of the solar cell and then attaching a second pre-crosslinked film to the side of the first pre-crosslinked film facing away from the solar cell, the pre-crosslinking degree of the front encapsulation film in the photovoltaic module is changed, so that the first pre-crosslinked film and the second pre-crosslinked film form a pre-crosslinking gradient, thereby effectively improving the reliability of the photovoltaic module.

[0014] In some embodiments, the pre-crosslinking degree of the first pre-crosslinked film is 30% to 60%, and the pre-crosslinking degree of the second pre-crosslinked film is 5% to 20%. This embodiment ensures that the reliability test requirements of the photovoltaic module are met by setting the pre-crosslinking degree range of the first pre-crosslinked film to 30% to 60% and the pre-crosslinking degree range of the second pre-crosslinked film to 5% to 20%. This is because if the pre-crosslinking degree ranges of the first and second pre-crosslinked films are outside the aforementioned ranges, the photovoltaic module may not pass the reliability test.

[0015] In some embodiments, the basis weight of the second pre-crosslinked film is 250 g / m³. 2 ~400g / m 2 The thickness of the second pre-crosslinked film is 0.3 mm to 0.4 mm. In this embodiment, the basis weight of the second pre-crosslinked film is set to 250 g / m³. 2 ~400g / m 2 The thickness range of the second pre-crosslinked film is set to 0.3mm~0.4mm, thereby improving the production yield of the second pre-crosslinked film, reducing costs, and improving the reliability of photovoltaic modules.

[0016] In some embodiments, the basis weight of the first pre-crosslinked film is 50 g / m³. 2 ~300g / m 2 The thickness of the first pre-crosslinked film is 0.1 mm to 0.3 mm. In this embodiment, the basis weight of the first pre-crosslinked film is set to 50 g / m³. 2 ~300g / m 2 The thickness range of the first pre-crosslinked film is set to 0.1mm~0.3mm, thereby improving the production yield of the first pre-crosslinked film, reducing costs, and improving the reliability of photovoltaic modules.

[0017] In some embodiments, the pre-crosslinking degree of the back pre-crosslinked film is 30% to 60%. This embodiment improves the coating effect by setting the pre-crosslinking degree of the back pre-crosslinked film to a range of 30% to 60%.

[0018] In some embodiments, the basis weight of the back pre-crosslinked film is 50 g / m³. 2 ~300g / m 2 The thickness of the back pre-crosslinked film is 0.1 mm to 0.3 mm. In this embodiment, the basis weight range of the back pre-crosslinked film is set to 50 g / m³. 2 ~300g / m 2 The thickness range of the back pre-crosslinked film is set to 0.1mm~0.3mm, thereby improving the production yield of the back pre-crosslinked film while reducing costs.

[0019] In some embodiments, the first pre-crosslinked film is made of a polyolefin elastomer, an ethylene-vinyl acetate copolymer, or a polyolefin elastomer and an ethylene-vinyl acetate copolymer, and the second pre-crosslinked film is made of a polyolefin elastomer, an ethylene-vinyl acetate copolymer, or a polyolefin elastomer and an ethylene-vinyl acetate copolymer.

[0020] In some embodiments, the photovoltaic module further includes a frame that is fitted around the periphery of a laminate composed of the front glass, the second pre-crosslinked film, the first pre-crosslinked film, the solar cells, the back pre-crosslinked film, the back adhesive film, and the back sheet or the back glass. This embodiment facilitates the installation of the photovoltaic module by installing a frame around the periphery of the laminate.

[0021] Accordingly, this application also provides a method for producing photovoltaic modules, the method comprising:

[0022] The first adhesive film, the second adhesive film, and the third adhesive film are respectively subjected to pre-crosslinking treatment to obtain a first pre-crosslinked film, a second pre-crosslinked film, and a back pre-crosslinked film;

[0023] Multiple first pre-crosslinked films are respectively attached to the front side of each battery cell, and multiple back pre-crosslinked films are respectively attached to the back side of each battery cell, so that the battery cells are connected in series to form a battery string;

[0024] The front glass, the second pre-crosslinked film, the battery string, the back adhesive film, and the back plate or back glass are stacked from bottom to top to form a pre-laminated product.

[0025] The pre-laminated product is laminated to form a laminated part.

[0026] In some embodiments, the production method further includes:

[0027] Electroluminescence testing was performed on the laminated component;

[0028] The laminated parts that have passed the electroluminescence test are framed to form the finished photovoltaic module.

[0029] The photovoltaic module of this application includes a solar cell, a first pre-crosslinked film, a second pre-crosslinked film, a front glass, a back pre-crosslinked film, a back encapsulant film, and a backsheet or back glass. The first pre-crosslinked film is attached to the front of the solar cell, the second pre-crosslinked film is attached to the side of the first pre-crosslinked film facing away from the solar cell, the front glass is attached to the side of the second pre-crosslinked film facing away from the first pre-crosslinked film, the back pre-crosslinked film is attached to the back of the solar cell, the back encapsulant film is attached to the side of the back pre-crosslinked film facing away from the solar cell, and the backsheet or back glass is attached to the side of the back encapsulant film facing away from the back pre-crosslinked film. Compared with the prior art, this application, by attaching the first pre-crosslinked film to the front of the solar cell and then attaching the second pre-crosslinked film to the side of the first pre-crosslinked film facing away from the solar cell, thereby changing the pre-crosslinking degree of the front encapsulant film in the photovoltaic module, that is, improving the flowability of the encapsulant film, and forming a pre-crosslinking gradient between the first pre-crosslinked film and the second pre-crosslinked encapsulant film, can effectively improve the reliability performance of the photovoltaic module. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the structure of a photovoltaic module based on related technologies.

[0031] Figure 2 This is a schematic diagram of the structure of a photovoltaic module provided in an embodiment of this application.

[0032] Figure 3 A flowchart illustrating a method for producing photovoltaic modules according to an embodiment of this application.

[0033] Attached image labels:

[0034] 1. Front glass; 2. Second pre-crosslinked film; 3. First pre-crosslinked film; 4. Battery cell; 5. Back pre-crosslinked film; 6. Back adhesive film; 7. Back sheet; 101. Front glass; 102. Front adhesive film; 103. Front pre-crosslinked film; 104. Battery cell; 105. Back pre-crosslinked film; 106. Back adhesive film; 107. Back sheet. Detailed Implementation

[0035] 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. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0036] In the description of this application, unless otherwise expressly specified and limited, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance; unless otherwise specified or explained, the term "multiple" refers to two or more, and the term "various types" refers to two or more; the terms "connection," "fixed," etc., should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, an integral connection, or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0037] In the description of this specification, it should be understood that the directional terms such as "upper" and "lower" used in the embodiments of this application are used to describe the angles shown in the accompanying drawings and should not be construed as limiting the embodiments of this application. Furthermore, in the context, it should also be understood that when it is mentioned that an element is connected "upper" or "lower" to another element, it can be directly connected to the other element "upper" or "lower," or indirectly connected to the other element "upper" or "lower" through an intermediate element.

[0038] Solar cells can generally be divided into crystalline silicon cells and thin-film cells based on their materials. Crystalline silicon cell technology uses silicon wafers as substrates and is further divided into P-type cells and N-type cells based on the differences in silicon wafers. Both types of cells generate electricity based on the separation of photogenerated carriers through PN junctions.

[0039] Crystalline silicon solar cells mainly include the following types:

[0040] 1. Heterojunction with Intrinsic Thin-layer (HIT) solar cell: Heterojunction solar cells have a symmetrical bifacial structure. The middle layer is N-type crystalline silicon. On the front side, intrinsic amorphous silicon thin films and P-type amorphous silicon thin films are deposited sequentially to form a PN junction. On the back side, intrinsic amorphous silicon thin films and N-type amorphous silicon thin films are deposited sequentially to form a back surface field. Heterojunction solar cells benefit from the dual passivation effect of the N-type silicon substrate and amorphous silicon on the substrate surface defects, and have the advantage of high efficiency.

[0041] 2. Back Contact Cell (BC): A back contact cell refers to a cell where both the main and fine metal grid lines (including the main grid lines and the fine grid lines) and the PN junction are located on the back side of the cell, with the metal grid lines arranged alternately. This structure reduces optical losses and results in a higher short-circuit current Jsc because there are no metal grid lines or other structures obstructing the front side (light conversion surface) of the cell. Simultaneously, the back side of the cell allows for wider metal grid lines, reducing the series resistance Rs and thus improving the fill factor FF. Furthermore, the open-circuit voltage gain from the front surface field and good passivation further increases the output power of the back contact cell, leading to its high conversion efficiency.

[0042] 3. Passivated Emitter Rear Cell (PERC): PERC cells use a passivation film to passivate the back of the cell, replacing the all-aluminum back field. This enhances the reflection of light on the inner back of the silicon substrate and can reduce the recombination rate on the back of the cell.

[0043] 4. Tunnel Oxide Passivated Contact (TOPCON) Cells: TOPCON cells are a new type of high-efficiency solar photovoltaic cell. Their structure mainly includes an N-type monocrystalline silicon substrate, a tunneling dielectric layer formed by ultrathin silicon oxide (SiOx) or silicon nitride (SiNx) deposited on the N-type monocrystalline silicon substrate, and a doped polycrystalline silicon layer covering the tunneling dielectric layer. The passivation effect of the tunneling dielectric layer allows electrons to tunnel to the doped polycrystalline silicon layer or the N-type monocrystalline silicon substrate in contact with the tunneling dielectric layer, while simultaneously blocking the passage of holes and reducing electron-hole recombination at the interface, thus achieving selective carrier transport.

[0044] Thin-film batteries include perovskite solar cells (PSCs), which use semiconductor materials with an ABX3 structure to capture sunlight and convert it into electrical energy, where A is a bulky cation, B is a transition metal ion, and X is a halide anion.

[0045] Crystalline silicon solar cells are relatively fragile and cannot withstand harsh external conditions independently. Therefore, individual crystalline silicon solar cells need to be connected in series and parallel, encapsulated, and then connected to external wires to become solar cell modules that can be used independently as photovoltaic power sources.

[0046] Reference Figure 1As shown, in related technologies, photovoltaic modules typically include a front glass 101, a front encapsulant film (non-pre-crosslinked film) 102, a front pre-crosslinked coating 103, a solar cell 104, a back pre-crosslinked coating 105, a back encapsulant film 106, and a backsheet 107. Specifically, the front pre-crosslinked coating 103 is attached to the front side of the solar cell 104, the front encapsulant film 102 is attached to the side of the front pre-crosslinked coating 103 facing away from the solar cell 104, the front glass 101 is attached to the side of the front encapsulant film 102 facing away from the front pre-crosslinked coating 103, the back pre-crosslinked coating 105 is attached to the back side of the solar cell 104, the back encapsulant film 106 is attached to the side of the back pre-crosslinked coating 105 facing away from the solar cell 104, and the backsheet 107 is attached to the side of the back encapsulant film 106 facing away from the back pre-crosslinked coating 105. However, the inventors discovered through long-term practice that if conventional encapsulant films (non-pre-crosslinked films) are used for encapsulation in photovoltaic modules, the difference in the degree of pre-crosslinking between the front encapsulant film and the front pre-crosslinked coating film will lead to a decrease in the reliability of photovoltaic modules.

[0047] Reference Figure 2 As shown, an embodiment of this application discloses a photovoltaic module, which includes a solar cell 4, a first pre-crosslinked film 3, a second pre-crosslinked film 2, a front glass 1, a back pre-crosslinked film 5, a back adhesive film 6, a backplate 7, and a frame. The first pre-crosslinked film 3 is attached to the front of the solar cell 4, the second pre-crosslinked film 2 is attached to the side of the first pre-crosslinked film 3 facing away from the solar cell 4, and the front glass 1 is attached to the side of the second pre-crosslinked film 2 facing away from the first pre-crosslinked film 3. The back pre-crosslinked film 5 is attached to the back of the solar cell 4, the back adhesive film 6 is attached to the side of the back pre-crosslinked film 5 facing away from the solar cell 4, and the backplate 7 is attached to the side of the back adhesive film 6 facing away from the back pre-crosslinked film 5, forming a laminate. The frame is fitted around the periphery of the laminate composed of the front glass 1, the second pre-crosslinked film 2, the first pre-crosslinked film 3, the solar cell 4, the back pre-crosslinked film 5, the back adhesive film 6, and the backplate 7 to form the finished photovoltaic module.

[0048] In the actual manufacturing process of photovoltaic modules, the individual cells are first connected in series to form a cell string. Then, the cell string, various film layers, front glass, and backsheet are stacked to form a pre-laminated product. This pre-laminated product is then laminated to form a laminate. After processes such as EL testing (electroluminescence testing), framing, junction box assembly, cleaning, IV testing (current-voltage characteristic testing), and finished product inspection, a finished product ready for shipment is finally obtained. Specifically, during the string welding of the individual cells, one end of the welding wire is placed on the front of one cell, and the other end on the back of another. A first pre-crosslinked film 3 is then applied to the front of the cell, and a back pre-crosslinked film 5 is applied to the back of the cell. This first pre-crosslinked film 3 fixes one end of the welding wire to the front of the cell, and the back pre-crosslinked film 5 fixes the other end to the back of the cell, thus achieving the series connection between the cells to form a cell string. When laminating the battery string, each film layer, the front glass and the back sheet, the front glass, the second pre-crosslinked film, the battery string, the back adhesive film and the back sheet are stacked from bottom to top to form the pre-lamination product. The pre-lamination product is then laminated by a laminator to obtain the laminated part.

[0049] In this embodiment, the photovoltaic module includes a backsheet 7, which is attached to the side of the back film 6 facing away from the solar cells 4. It is understood that in other embodiments, the backsheet can be replaced with a back glass, which is attached to the side of the back film 6 facing away from the solar cells 4.

[0050] This application employs a first pre-crosslinked film 3 and a back pre-crosslinked film 5 with a certain degree of pre-crosslinking to coat the solar cells, thereby improving the coating effect during the string welding process of each solar cell. If ordinary adhesive film is used to coat the solar cells, the adhesive film may flow between the welding wire and the solar cell, causing poor soldering. At the same time, using the first pre-crosslinked film 3 and the back pre-crosslinked film 5 with a certain degree of pre-crosslinking to coat the solar cells can also improve the EL test effect of the laminated components. In addition, this application applies the first pre-crosslinked film 3 to the front of the solar cell 4 and then applies the second pre-crosslinked film 2 to the side of the first pre-crosslinked film 3 facing away from the solar cell 4. By changing the pre-crosslinking degree of the front encapsulation film in the photovoltaic module, i.e., improving the film flowability, the first pre-crosslinked film 3 and the second pre-crosslinked film 2 form a pre-crosslinking gradient, thereby effectively improving the reliability of the photovoltaic module.

[0051] In this embodiment, the pre-crosslinking degree of the first pre-crosslinked film 3 is 30%~60%, the pre-crosslinking degree of the second pre-crosslinked film 2 is 5%~20%, and the pre-crosslinking degree of the back pre-crosslinked film 5 is 30%~60%. Specifically, the pre-crosslinking degree of the first pre-crosslinked film 3 can be 30%, 40%, 50%, 60%, etc., the pre-crosslinking degree of the second pre-crosslinked film 2 can be 5%, 10%, 15%, 20%, etc., and the pre-crosslinking degree of the back pre-crosslinked film 5 can be 30%, 40%, 50%, 60%, etc.

[0052] Through long-term practice, the inventors discovered that different pre-crosslinking ranges of the encapsulating film in photovoltaic modules can affect the manufacturing process and reliability. This embodiment satisfies the reliability testing requirements of photovoltaic modules by setting the pre-crosslinking degree range of the first pre-crosslinked film 3 to 30%~60%, the pre-crosslinking degree range of the second pre-crosslinked film 2 to 5%~20%, and the pre-crosslinking degree range of the back pre-crosslinked film 5 to 30%~60%. This is because if the pre-crosslinking degree ranges of the first pre-crosslinked film 3, the second pre-crosslinked film 2, and the back pre-crosslinked film 5 are outside these ranges, the reliability testing requirements of the photovoltaic modules may not be met.

[0053] The basis weight of the first pre-crosslinked membrane 3 is 50 g / m³. 2 ~300g / m 2 The basis weight of the second pre-crosslinked membrane 2 is 250 g / m³. 2 ~400g / m 2 The basis weight of the pre-crosslinked film 5 on the back is 50 g / m³. 2 ~300g / m 2 Specifically, the basis weight of the first pre-crosslinked film 3 can be 50 g / m³. 2 70g / m 2 100g / m 2 150g / m 2 200g / m 2 250g / m 2 300g / m 2 The basis weight of the second pre-crosslinked membrane 2 can be 250 g / m³. 2 300g / m 2 350g / m 2 400g / m 2 The basis weight of the pre-crosslinked film 5 on the back side can be 50 g / m³. 2 70g / m 2 100g / m 2 150g / m 2 200g / m 2 250g / m 2 300g / m 2 wait.

[0054] The basis weight of the encapsulant film affects its manufacturability at the encapsulant film manufacturer's end. If the film is too thin, it can lead to low production yield and increased costs; if the film is too thick, it will result in material waste and high costs. At the photovoltaic module manufacturing end, the basis weight of the encapsulant film affects the manufacturing process and reliability of the photovoltaic module. In this embodiment, the basis weight range of the first pre-crosslinked film 3 is set to 50 g / m³. 2 ~300g / m 2 The basis weight range of the second pre-crosslinked membrane 2 is set to 250 g / m³. 2 ~400g / m 2 The basis weight range of the pre-crosslinked film 5 on the back side is set to 50 g / m³. 2 ~300g / m 2 This improves the yield of encapsulant film production, reduces costs, and enhances the reliability of photovoltaic modules.

[0055] The thickness of the first pre-crosslinked film 3 is 0.1 mm to 0.3 mm, the thickness of the second pre-crosslinked film 2 is 0.3 mm to 0.4 mm, and the thickness of the back pre-crosslinked film 5 is 0.1 mm to 0.3 mm. Specifically, the thickness of the first pre-crosslinked film 3 can be 0.1 mm, 0.15 mm, 0.2 mm, 0.25 mm, 0.3 mm, etc., the thickness of the second pre-crosslinked film 2 can be 0.3 mm, 0.32 mm, 0.34 mm, 0.36 mm, 0.38 mm, 0.4 mm, etc., and the thickness of the back pre-crosslinked film 5 can be 0.1 mm, 0.15 mm, 0.2 mm, 0.25 mm, 0.3 mm, etc.

[0056] The thickness of the encapsulant film affects its manufacturability at the encapsulant film manufacturer's end. If the film is too thin, it can lead to low production yield and increased costs; if the film is too thick, it may result in material waste and high costs. At the photovoltaic module manufacturing end, the film thickness affects the process and reliability of the photovoltaic module. This embodiment sets the thickness range of the first pre-crosslinked film 3 to 0.1mm~0.3mm, the thickness range of the second pre-crosslinked film 2 to 0.3mm~0.4mm, and the basis weight range of the back pre-crosslinked film 5 to 0.1mm~0.3mm, thereby improving the encapsulant film production yield while reducing costs and enhancing the reliability of the photovoltaic module.

[0057] The material of the pre-crosslinked film is mainly related to the type of adhesive film. For example, the first pre-crosslinked film 3 can be a POE (polyolefin elastomer) pre-crosslinked film, and the material of the POE pre-crosslinked film can be polyolefin elastomer (abbreviated as POE); the first pre-crosslinked film 3 can also be an EPE (expandable polyethylene) pre-crosslinked film, and the material of the EPE pre-crosslinked film can be polyolefin elastomer and ethylene-vinyl acetate copolymer (abbreviated as EVA); the first pre-crosslinked film 3 can also be an EVA pre-crosslinked film, and the material of the EVA pre-crosslinked film can be ethylene-vinyl acetate copolymer. The back pre-crosslinked film 5 can be a POE pre-crosslinked film, an EPE pre-crosslinked film, or an EVA pre-crosslinked film. The first pre-crosslinked film 3 is mainly used to fix one end of the welding wire to the front of the battery cell, and the back pre-crosslinked film is mainly used to fix the other end of the welding wire to the back of the battery cell.

[0058] The second pre-crosslinked film 2 can be a POE pre-crosslinked film, an EPE pre-crosslinked film, or an EVA pre-crosslinked film, and the back adhesive film 6 can be made of polyolefin elastomer, expandable polyethylene, or ethylene-vinyl acetate copolymer. The second pre-crosslinked film 2 and the back adhesive film 6 are used to encapsulate and protect the battery cells, prevent the external environment from affecting the performance of the battery cells, and bond the front glass, battery string, and back sheet together.

[0059] The front glass can be ultra-clear glass, which has a high light transmittance of over 92%. It is mainly used to protect the solar cells from damage caused by various harsh environmental factors such as temperature, humidity and external impact, while not affecting their absorption of light energy.

[0060] The backsheet can be a composite film made of multiple layers of polymer films bonded together by rolling. It is mainly used to protect the internal encapsulation materials and cells of photovoltaic modules from mechanical damage and external environmental corrosion. It also has good insulation properties, which largely determine the working life of photovoltaic modules.

[0061] Accordingly, refer to Figure 3 As shown in the figure, an embodiment of this application also discloses a method for producing photovoltaic modules, used to produce the photovoltaic modules described in the above embodiments. The method includes the following steps:

[0062] S11. The first adhesive film, the second adhesive film and the third adhesive film are respectively subjected to pre-crosslinking treatment to obtain the first pre-crosslinked film, the second pre-crosslinked film and the back pre-crosslinked film.

[0063] Specifically, pre-crosslinking treatment of the film refers to reacting the crosslinking agent with the polymer chain at a lower temperature to form a partially crosslinked structure, thereby obtaining pre-crosslinked films with different degrees of pre-crosslinking. Among them, the pre-crosslinking degree of the first pre-crosslinked film 3 ranges from 30% to 60%, the pre-crosslinking degree of the second pre-crosslinked film 2 ranges from 5% to 20%, and the pre-crosslinking degree of the back pre-crosslinked film 5 ranges from 30% to 60%.

[0064] S12. Multiple first pre-crosslinked films are respectively attached to the front side of each battery cell, and multiple back pre-crosslinked films are respectively attached to the back side of each battery cell, so that the battery cells are connected in series to form a battery string.

[0065] Specifically, before stringing the battery cells, each cell needs to be categorized by power and current. The categorized cells are then marked with different categorization levels. For example, categorization can be done in 0.1 power increments, with each categorization marked with a different color for differentiation. Then, multiple cells of the same categorization level are connected in series, front and back, using welding wire to form a battery string. For example, one end of the welding wire can be placed on the front of one battery cell, and the other end on the back of another. A first pre-crosslinked film 3 is then applied to the front of the battery cell using a lamination process, and a back pre-crosslinked film 5 is applied to the back of the battery cell using a lamination process. This fixes one end of the welding wire to the front of the battery cell 4 using the first pre-crosslinked film 3 and the other end to the back of the battery cell 4 using the back pre-crosslinked film 5, thus achieving series connection between the battery cells 4 to form a battery string.

[0066] S13. The front glass, the second pre-crosslinked film, the battery string, the back adhesive film, and the back plate or back glass are stacked from bottom to top to form a pre-laminated product.

[0067] Specifically, the front glass 1 can be placed on the workbench first, and then the second pre-crosslinked film 2 can be placed on the front glass 1. Then, the battery strings can be arranged on the second pre-crosslinked film 2 by a layout machine, and then stacked by a stacking welding machine. Then, the back adhesive film 6 can be covered on the battery strings, and finally the back plate 7 can be covered on the back adhesive film 6 to obtain the pre-lamination product.

[0068] S14. Perform appearance inspection and first electroluminescence test on the pre-laminated product.

[0069] Specifically, the pre-laminated products after lamination undergo preliminary appearance inspection to ensure there are no appearance defects. Then, they are placed in an EL tester for the first electroluminescence test to observe whether there are any battery defects. If so, the pre-laminated products with defects are sent to the cell replacement station for cell replacement.

[0070] S15. The pre-lamination product that has passed the appearance inspection and the first electroluminescence test is laminated to obtain the laminated part.

[0071] Specifically, the pre-laminated products can be placed into a laminator, and then the front glass 1, the second pre-crosslinked film 2, the battery string, the back adhesive film 6 and the back plate 7 can be pressed together in a high temperature and vacuum environment to form a laminate of an integrated product.

[0072] S16. Perform a second electroluminescence test on the laminate.

[0073] Specifically, the laminate is placed in an EL tester for a second electroluminescence test to observe whether there are any battery defects. If so, the defective laminate is repaired.

[0074] S17. The laminated parts that pass the second electroluminescence test are framed.

[0075] Specifically, the laminated product is fitted with a frame to give it a certain load-bearing capacity and installation function.

[0076] This application applies a first pre-crosslinked film 3 to the front of the solar cell 4, and then applies a second pre-crosslinked film 2 to the side of the first pre-crosslinked film 3 facing away from the solar cell 4. This changes the pre-crosslinking degree of the encapsulating film on the front of the photovoltaic module, that is, improves the fluidity of the encapsulating film, and makes the first pre-crosslinked film 3 and the second pre-crosslinked film 2 form a pre-crosslinking gradient, thereby effectively improving the reliability of the photovoltaic module.

[0077] The above description is merely a preferred embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A method for producing a photovoltaic module, characterized in that, include: The first adhesive film, the second adhesive film, and the third adhesive film are respectively subjected to pre-crosslinking treatment to obtain a first pre-crosslinked film, a second pre-crosslinked film, and a back pre-crosslinked film; Multiple first pre-crosslinked films are respectively attached to the front side of each battery cell, and multiple back pre-crosslinked films are respectively attached to the back side of each battery cell, so that the battery cells are connected in series to form a battery string; The front glass, the second pre-crosslinked film, the battery string, the back adhesive film, and the back plate or back glass are stacked from bottom to top to form a pre-laminated product. The pre-laminated product is laminated to form a laminated part.

2. The production method according to claim 1, characterized in that, The degree of pre-crosslinking of the first pre-crosslinked film is 30% to 60%, and the degree of pre-crosslinking of the second pre-crosslinked film is 5% to 20%.

3. The production method according to claim 2, characterized in that, The basis weight of the second pre-crosslinked film is 250 g / m³. 2 ~400g / m 2 The thickness of the second pre-crosslinked film is 0.3 mm to 0.4 mm.

4. The production method according to claim 2, characterized in that, The basis weight of the first pre-crosslinked film is 50 g / m³. 2 ~300g / m 2 The thickness of the first pre-crosslinked film is 0.1 mm to 0.3 mm.

5. The production method according to claim 1, characterized in that, The degree of pre-crosslinking of the back pre-crosslinked film is 30%~60%.

6. The production method according to claim 5, characterized in that, The basis weight of the pre-crosslinked film on the back is 50 g / m³. 2 ~300g / m 2 The thickness of the pre-crosslinked film on the back is 0.1 mm to 0.3 mm.

7. The production method according to claim 1, characterized in that, The first pre-crosslinked film is made of polyolefin elastomer, ethylene-vinyl acetate copolymer, or a combination of polyolefin elastomer and ethylene-vinyl acetate copolymer, and the second pre-crosslinked film is made of polyolefin elastomer, ethylene-vinyl acetate copolymer, or a combination of polyolefin elastomer and ethylene-vinyl acetate copolymer.

8. The production method according to any one of claims 1 to 7, characterized in that, The production method further includes: fitting a frame around the periphery of a laminate composed of the front glass, the second pre-crosslinked film, the first pre-crosslinked film, the battery cell, the back pre-crosslinked film, the back adhesive film, and the back plate or the back glass.

9. The production method according to any one of claims 1 to 7, characterized in that, The production method further includes: Electroluminescence testing was performed on the laminated component; The laminated parts that have passed the electroluminescence test are framed to form the finished photovoltaic module.

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