Photovoltaic module and production method thereof

Abstract

The invention discloses a photovoltaic module and a production method of the photovoltaic module, and the photovoltaic module comprises a battery piece, a first pre-crosslinking film, a second pre-crosslinking film, front glass, a back pre-crosslinking film, a back adhesive film and a back plate or back glass, the first pre-crosslinking film is pasted on the front surface of the battery piece, and the second pre-crosslinking film is pasted on the back surface of the battery piece; the second pre-crosslinking film is attached to the side, back to the battery piece, of the first pre-crosslinking film, the front glass is attached to the side, back to the first pre-crosslinking film, of the second pre-crosslinking film, the back pre-crosslinking film is attached to the back face of the battery piece, and the back adhesive film is attached to the side, back to the battery piece, of the back pre-crosslinking film. And the back plate or the back glass is attached to one side, back to the back pre-crosslinking film, of the back adhesive film. According to the application, the first pre-crosslinking film is attached to the front surface of the battery piece, and then the second pre-crosslinking film is attached to one side, back to the battery piece, of the first pre-crosslinking film, so that the first pre-crosslinking film and the second pre-crosslinking film form a pre-crosslinking gradient, and the reliability of the photovoltaic module can be effectively improved.

Description

Technical Field

[0001] The present application relates to the technical field of solar cells, and in particular to a photovoltaic module and a method for producing the photovoltaic module. Background Art

[0002] In the manufacture and application of busbarless solar cells, the coating of busbarless solar cells has a pre-crosslinking degree. If conventional adhesive film is used for packaging, the difference in the pre-crosslinking degree of the two films may lead to a reduction in the reliability of the corresponding photovoltaic modules. Summary of the invention

[0003] In order to overcome the problems existing in the above-mentioned prior art, the main purpose of the present application is to provide a photovoltaic module and a production method of a photovoltaic module that can improve reliability.

[0004] In order to achieve the above objectives, this application specifically adopts the following technical solutions:

[0005] The present application provides a photovoltaic assembly, the photovoltaic assembly comprising:

[0006] Battery cells;

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

[0008] A second pre-cross-linked film, the second pre-cross-linked film is attached to a side of the first pre-cross-linked film facing away from the battery cell;

[0009] A front glass, wherein the front glass is attached to a side of the second pre-cross-linked film facing away from the first pre-cross-linked film;

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

[0011] A back adhesive film, the back adhesive film being attached to a side of the back pre-crosslinked film facing away from the battery cell;

[0012] A back plate or a back glass, wherein the back plate or the back glass is attached to a side of the back adhesive film that is away from the back pre-cross-linked film.

[0013] In this embodiment, the first pre-cross-linked film is attached to the front side of the battery cell, and the second pre-cross-linked film is attached to the side of the first pre-cross-linked film facing away from the battery cell, thereby changing the pre-cross-linking degree of the front packaging film in the photovoltaic module, so that the first pre-cross-linked film and the second pre-cross-linked film form a pre-cross-linking gradient, thereby effectively improving the reliability performance 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%. In this embodiment, the pre-crosslinking degree range of the first pre-crosslinked film is set to 30% to 60%, and the pre-crosslinking degree range of the second pre-crosslinked film is set to 5% to 20%, thereby ensuring that the reliability test of the photovoltaic module meets the requirements, because if the pre-crosslinking degree range of the first pre-crosslinked film and the second pre-crosslinked film is outside the above range, the photovoltaic module may not pass the reliability test.

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

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

[0017] In some embodiments, the pre-crosslinking degree of the back pre-crosslinked film is 30% to 60%. In this embodiment, the pre-crosslinking degree of the back pre-crosslinked film is set to 30% to 60%, thereby improving the lamination effect.

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

[0019] In some embodiments, the material of the first pre-cross-linked film is polyolefin elastomer, ethylene-vinyl acetate copolymer, or polyolefin elastomer and ethylene-vinyl acetate copolymer, and the material of the second pre-cross-linked film is polyolefin elastomer, ethylene-vinyl acetate copolymer, or polyolefin elastomer and ethylene-vinyl acetate copolymer.

[0020] In some embodiments, the photovoltaic module further comprises a frame, and the frame is sleeved around the periphery of the laminate composed of the front glass, the second pre-cross-linked film, the first pre-cross-linked film, the cell, the back pre-cross-linked film, the back adhesive film and the back plate or the back glass. In this embodiment, the frame is installed on the periphery of the laminate, thereby facilitating the installation of the photovoltaic module.

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

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

[0023] affixing a plurality of the first pre-crosslinked films to the front side of each battery cell, and affixing a plurality of the back side pre-crosslinked films to the back side of each battery cell, so that each battery cell is 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 the back glass are stacked from bottom to top to form a pre-laminated product;

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

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

[0027] performing an electroluminescence test on the laminate;

[0028] The laminate that has passed the electroluminescence test is framed to form a finished product of the photovoltaic module.

[0029] The photovoltaic module of the present application includes a battery 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 back plate or back glass. The first pre-crosslinked film is attached to the front of the battery cell, the second pre-crosslinked film is attached to the side of the first pre-crosslinked film that is not facing the battery cell, the front glass is attached to the side of the second pre-crosslinked film that is not facing the first pre-crosslinked film, the back pre-crosslinked film is attached to the back of the battery cell, the back adhesive film is attached to the side of the back pre-crosslinked film that is not facing the battery cell, and the back plate or back glass is attached to the side of the back adhesive film that is not facing the back pre-crosslinked film. Compared with the prior art, the present application attaches the first pre-crosslinked film to the front of the battery cell, and then attaches the second pre-crosslinked film to the side of the first pre-crosslinked film that is not facing the battery cell, thereby changing the pre-crosslinking degree of the front encapsulation adhesive film in the photovoltaic module, that is, improving the fluidity of the adhesive film, 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. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 A schematic diagram of the structure of a photovoltaic module of the related art.

[0031] Figure 2 A schematic diagram of the structure of a photovoltaic module provided in an embodiment of the present application.

[0032] Figure 3 A flow chart of a method for producing a photovoltaic module provided in an embodiment of the present application.

[0033] Figure ID:

[0034] 1. front glass; 2. second pre-cross-linked film; 3. first pre-cross-linked film; 4. battery cell; 5. back pre-cross-linked film; 6. back adhesive film; 7. backplane; 101. front glass; 102. front adhesive film; 103. front pre-cross-linked coating; 104. battery cell; 105. back pre-cross-linked coating; 106. back adhesive film; 107. backplane. DETAILED DESCRIPTION

[0035] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0036] In the description of this application, unless otherwise clearly specified and limited, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance; unless otherwise specified or explained, the term "multiple" refers to two or more, and the term "multiple" refers to two or more; the terms "connected", "fixed", etc. should be understood in a broad sense, for example, "connected" can be a fixed connection, a detachable connection, an integral connection, or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0037] In the description of this specification, it should be understood that the directional words such as "upper" and "lower" described in the embodiments of the present application are described at the angles shown in the accompanying drawings and should not be understood as limiting the embodiments of the present application. In addition, in the context, it should also be understood that when it is mentioned that an element is connected to another element "upper" or "lower", it can not only be directly connected to another element "upper" or "lower", but also indirectly connected to another 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 the materials. Crystalline silicon cell technology uses silicon wafers as substrates and is divided into P-type cells and N-type cells based on the differences in silicon wafers. The power generation principles of both types of cells are based on the separation of photogenerated carriers through PN junctions.

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

[0040] 1. Heterojunction cell (HIT): Heterojunction cells have a symmetrical double-sided cell structure, with N-type crystalline silicon in the middle. Intrinsic amorphous silicon film and P-type amorphous silicon film are deposited on the front in sequence to form a PN junction; intrinsic amorphous silicon film and N-type amorphous silicon film are deposited on the back in sequence to form a back surface field. Heterojunction cells benefit from the double passivation effect of N-type silicon substrate and amorphous silicon on substrate surface defects, and have the advantage of high efficiency.

[0041] 2. Back Contact Cell (BC): Back contact cell refers to a cell in which the bipolar metal grid lines (including bipolar main grid lines and bipolar fine grid lines) and the PN junction are located on the back of the cell, and the bipolar metal grid lines are distributed alternately. This type of back contact cell can reduce optical loss and has a higher short-circuit current Jsc because there is no bipolar metal grid line or other structure blocking the front of the cell (light conversion surface). At the same time, the back of the cell can allow for wider bipolar metal grid lines to reduce the series resistance Rs of the cell, thereby increasing the fill factor FF. In addition, the front surface field of the cell and the open circuit voltage gain brought about by good passivation increase the output power of the back contact cell, thereby increasing the conversion efficiency of the back contact cell.

[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, enhancing the internal back reflection of light in the silicon substrate, and reducing the recombination rate on the back of the cell.

[0043] 4. Tunnel Oxide Passivated Contact Cell (TOPCON), TOPCon cell is a new type of high-efficiency solar photovoltaic cell, whose structure mainly includes N-type single crystal silicon substrate, tunnel dielectric layer formed by ultra-thin silicon oxide (SiOx) or silicon nitride (SiNx) deposited on the N-type single crystal silicon substrate, and doped polysilicon layer covering the tunnel dielectric layer. Among them, the passivation effect of the tunnel dielectric layer allows electrons to reach the doped polysilicon layer or N-type single crystal silicon substrate in contact with the tunnel dielectric layer through the tunnel effect, while blocking the passage of holes, reducing the recombination of electrons and holes at the interface, thereby forming selective transmission of carriers.

[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 halogen anion.

[0045] Crystalline silicon solar cells are relatively brittle and cannot withstand harsh external conditions independently. Therefore, it is necessary to connect the individual crystalline silicon solar cells in series and parallel, package them, and then connect external wires to become solar cell modules that can be used independently as photovoltaic power sources.

[0046] Reference Figure 1As shown, in the related art, a photovoltaic module generally includes a front glass 101, a front adhesive film (non-pre-crosslinked film) 102, a front pre-crosslinked coating 103, a battery cell 104, a back pre-crosslinked coating 105, a back adhesive film 106 and a back sheet 107. Among them, the front pre-crosslinked coating 103 is attached to the front of the battery cell 104, the front adhesive film 102 is attached to the side of the front pre-crosslinked coating 103 that is not facing the battery cell 104, the front glass 101 is attached to the side of the front adhesive film 102 that is not facing the front pre-crosslinked coating 103, the back pre-crosslinked coating 105 is attached to the back of the battery cell 104, the back adhesive film 106 is attached to the side of the back pre-crosslinked coating 105 that is not facing the battery cell 104, and the back sheet 107 is attached to the side of the back adhesive film 106 that is not facing the back pre-crosslinked coating 105. However, the inventors have found in long-term practice that in the packaging of photovoltaic modules, if conventional adhesive films (non-pre-crosslinked adhesive films) are used for packaging, the difference in pre-crosslinking degree between the front adhesive film and the front pre-crosslinked coating will lead to a decrease in the reliability performance of the photovoltaic modules.

[0047] Reference Figure 2 As shown, the embodiment of the present application discloses a photovoltaic module, which includes a battery 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 back plate 7 and a frame. The first pre-crosslinked film 3 is attached to the front of the battery cell 4, the second pre-crosslinked film 2 is attached to the side of the first pre-crosslinked film 3 that is not facing the battery cell 4, and the front glass 1 is attached to the side of the second pre-crosslinked film 2 that is not facing the first pre-crosslinked film 3. The back pre-crosslinked film 5 is attached to the back of the battery cell 4, the back adhesive film 6 is attached to the side of the back pre-crosslinked film 5 that is not facing the battery cell 4, and the back plate 7 is attached to the side of the back adhesive film 6 that is not facing the back pre-crosslinked film 5, forming a laminate. The frame is sleeved 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 battery cell 4, the back pre-crosslinked film 5, the back adhesive film 6 and the back plate 7 to form a finished product of the photovoltaic module.

[0048] In the actual production process of photovoltaic modules, it is necessary to first connect each battery cell in series to form a battery string, and then stack the battery string, each film layer, front glass and back plate to form a pre-laminated product, and then laminate the pre-laminated product to form a laminate, and then pass the EL test (electroluminescence test), frame installation, junction box installation, cleaning, IV test (current voltage characteristic test), finished product inspection and other processes to finally obtain a finished product that can be shipped. Among them, when the battery cells are serially welded, one end of the welding wire can be set on the front of one of the battery cells, and the other end of the welding wire can be set on the back of another battery cell, and then the first pre-crosslinking film 3 is set on the front of the battery cell, and the back pre-crosslinking film 5 is set on the back of the battery cell, so that one end of the welding wire is fixed to the front of the battery cell through the first pre-crosslinking film 3, and the other end of the welding wire is fixed to the back of the battery cell through the back pre-crosslinking film 5, so as to realize the series connection between the battery cells to form a battery string. When laminating the battery string, each film layer, front glass and back plate, the front glass, the second pre-cross-linked film, the battery string, the back adhesive film and the back plate are stacked from bottom to top to form a pre-lamination product, and then the pre-lamination product is laminated by a laminator to obtain a laminated part.

[0049] In this embodiment, the photovoltaic module includes a back plate 7, which is attached to the side of the back film 6 facing away from the cell 4. It can be understood that in other implementations, the back plate can also be replaced by a back glass, which is attached to the side of the back film 6 facing away from the cell 4.

[0050] The present application uses a first pre-crosslinked film 3 and a back pre-crosslinked film 5 with a certain pre-crosslinking degree to coat the battery cell, thereby improving the coating effect during the series welding process of each battery cell. If an ordinary adhesive film is used to coat the battery cell, the adhesive film may flow between the welding wire and the battery cell, causing a cold weld; at the same time, the first pre-crosslinked film 3 and the back pre-crosslinked film 5 with a pre-crosslinking degree are used to coat the battery cell, which can also improve the EL test effect of the laminated component after lamination. In addition, the present application attaches the first pre-crosslinked film 3 to the front of the battery cell 4, and then attaches the second pre-crosslinked film 2 to the side of the first pre-crosslinked film 3 facing away from the battery cell 4, thereby changing the pre-crosslinking degree of the front packaging adhesive film in the photovoltaic module, that is, improving the fluidity of the adhesive film, so that the first pre-crosslinked film 3 and the second pre-crosslinked film 2 form a pre-crosslinked 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% to 60%, the pre-crosslinking degree of the second pre-crosslinked film 2 is 5% to 20%, and the pre-crosslinking degree of the back pre-crosslinked film 5 is 30% to 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] The inventor has found in long-term practice that in photovoltaic modules, different pre-crosslinking ranges of the encapsulation film will affect the process effect of the photovoltaic module, and will also affect the reliability of the photovoltaic module. This embodiment meets the reliability test requirements of the photovoltaic module by setting the pre-crosslinking degree range of the first pre-crosslinked film 3 to 30% to 60%, the pre-crosslinking degree range of the second pre-crosslinked film 2 to 5% to 20%, and the pre-crosslinking degree range of the back pre-crosslinked film 5 to 30% to 60%. 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 the above ranges, the reliability test requirements of the photovoltaic module may not be met.

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

[0054] The weight of the film will affect the manufacturability of the film at the film manufacturer's end. If the film is too thin, it will easily lead to low production yield and increased costs. If the film is too thick, it will cause waste of materials and high costs. The weight of the film will affect the process and reliability of the photovoltaic module at the photovoltaic module manufacturing end. In this embodiment, the weight range of the first pre-crosslinked film 3 is set to 50g / m 2 ~300g / m 2 The weight range of the second pre-crosslinked film 2 is set to 250 g / m 2 ~400g / m 2 The weight range of the back pre-crosslinked film 5 is set to 50 g / m 2 ~300g / m 2 , thereby improving the film production yield while reducing costs and improving 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 film will affect the manufacturability of the film at the film manufacturer's end. If the film is too thin, it will easily lead to low production yield and increased costs. If the film is too thick, it may cause material waste and high costs. The thickness of the film will affect the process and reliability of the photovoltaic module at the photovoltaic module manufacturing end. In this embodiment, by setting 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 gram weight range of the back pre-crosslinked film 5 to 0.1mm-0.3mm, the film production yield is improved while reducing costs, and the reliability of the photovoltaic module is improved.

[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 a polyolefin elastomer (English full name: Polyolefinelastomer, referred to 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 a polyolefin elastomer and ethylene-vinyl acetate copolymer (English full name: Ethylene VinylAcetate Copolymer, referred to 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 material of the back adhesive film 6 can be a 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 plate together.

[0059] The front glass can be ultra-white glass, which has a high light transmittance of more than 92%. It is mainly used to protect the battery cells from various harsh environmental factors such as temperature, humidity, and external force impact, while not affecting its absorption of light energy.

[0060] The backplane can be a composite film made of multiple layers of polymer films that are rolled and bonded together. It is mainly used to protect the internal packaging materials and battery cells of photovoltaic modules from mechanical damage and external environmental corrosion. It also has good insulation properties, which largely determines the working life of photovoltaic modules.

[0061] Accordingly, refer to Figure 3 As shown, the embodiment of the present application further discloses a method for producing a photovoltaic module, which is used to produce the photovoltaic module described in the above embodiment. The production method comprises the following steps:

[0062] S11, performing pre-crosslinking treatment on the first adhesive film, the second adhesive film and the third adhesive film respectively to obtain a first pre-crosslinked film, a second pre-crosslinked film and a back pre-crosslinked film respectively.

[0063] Specifically, the pre-crosslinking treatment of the adhesive film refers to reacting the crosslinking agent with the polymer chain at a relatively low temperature to form a partially crosslinked structure to obtain pre-crosslinked films with different pre-crosslinking degrees. The pre-crosslinking degree of the first pre-crosslinked film 3 is in the range of 30% to 60%, the pre-crosslinking degree of the second pre-crosslinked film 2 is in the range of 5% to 20%, and the pre-crosslinking degree of the back pre-crosslinked film 5 is in the range of 30% to 60%.

[0064] S12, attaching a plurality of first pre-crosslinked films to the front side of each battery cell, attaching a plurality of back side pre-crosslinked films to the back side of each battery cell, so that each battery cell is connected in series to form a battery string.

[0065] Specifically, before the battery cells are serially welded, it is necessary to first classify each battery cell by power and current, and mark the classified battery cells as different class levels according to the class. For example, the power can be classified every 0.1, and each class is marked with a different color mark to distinguish. Then, the front and back sides of multiple battery cells of the same class level are connected in series by welding wire to form a battery string. For example, one end of the welding wire can be set on the front of one of the battery cells, and the other end of the welding wire can be set on the back of another battery cell. Then, the first pre-cross-linking film 3 is attached to the front of the battery cell through a coating process, and the back pre-cross-linking film 5 is attached to the back of the battery cell through a coating process, so that one end of the welding wire is fixed to the front of the battery cell 4 through the first pre-cross-linking film 3, and the other end of the welding wire is fixed to the back of the battery cell 4 through the back pre-cross-linking film 5, so as to realize the series connection between the battery cells 4 to form a battery string.

[0066] S13, stacking the front glass, the second pre-cross-linked film, the battery string, the back adhesive film and the back plate or the back glass 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-cross-linked film 2 can be placed on the front glass 1. Then, the battery string can be arranged on the second pre-cross-linked film 2 by a typesetting machine, and then the battery string can be covered with a back adhesive film 6. Finally, the back adhesive film 6 can be covered with a back panel 7 to obtain a pre-lamination product.

[0068] S14, performing appearance inspection and a first electroluminescence test on the product before lamination.

[0069] Specifically, the stacked pre-lamination products are subjected to a preliminary appearance inspection to ensure that there are no appearance defects, and then placed in an EL tester for the first electroluminescence test to observe whether there are battery defects. If so, the defective pre-lamination products are sent to the cell replacement station for cell replacement.

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

[0071] Specifically, the stacked pre-laminated product can be placed in a laminator, and then the front glass 1, the second pre-cross-linked film 2, the battery string, the back adhesive film 6 and the back panel 7 are pressed together in a high-temperature vacuum environment to form a laminated part of an integrated product.

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

[0073] Specifically, the laminate is placed in an EL tester to perform a second electroluminescence test to observe whether there are cell defects. If there are, the laminate with defects is repaired.

[0074] S17, framing the laminated pieces that have passed the second electroluminescence test.

[0075] Specifically, the laminated product is mounted on a frame so that it has a certain load capacity and installation function.

[0076] The present application forms a pre-crosslinking gradient between the first pre-crosslinking film 3 and the second pre-crosslinking film 2 by attaching the first pre-crosslinking film 3 to the front side of the battery cell 4 and then attaching the second pre-crosslinking film 2 to the side of the first pre-crosslinking film 3 facing away from the battery cell 4, thereby changing the pre-crosslinking degree of the front packaging film in the photovoltaic module, that is, improving the fluidity of the film, and allowing the first pre-crosslinking film 3 and the second pre-crosslinking film 2 to form a pre-crosslinking gradient, thereby effectively improving the reliability performance of the photovoltaic module.

[0077] The above is only a preferred specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A photovoltaic module, characterized in that: include: Battery cells; A first pre-crosslinked film, wherein the first pre-crosslinked film is attached to the front side of the battery cell; A second pre-cross-linked film, the second pre-cross-linked film is attached to a side of the first pre-cross-linked film facing away from the battery cell; A front glass, wherein the front glass is attached to a side of the second pre-cross-linked film facing away from the first pre-cross-linked film; A back pre-crosslinked film, the back pre-crosslinked film is attached to the back of the battery cell; A back adhesive film, the back adhesive film being attached to a side of the back pre-cross-linked film facing away from the battery cell; A back plate or a back glass, wherein the back plate or the back glass is attached to a side of the back adhesive film that is away from the back pre-cross-linked film.

2. The photovoltaic module according to claim 1, characterized in that: 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%.

3. The photovoltaic module according to claim 2, characterized in that: The weight of the second pre-crosslinked film is 250 g / m 2 ~400g / m 2 The thickness of the second pre-cross-linked film is 0.3 mm to 0.4 mm.

4. The photovoltaic module according to claim 2, characterized in that: The weight of the first pre-crosslinked film is 50 g / m 2 ~300g / m 2 , the thickness of the first pre-cross-linked film is 0.1 mm to 0.3 mm.

5. The photovoltaic module according to claim 1, characterized in that: The pre-crosslinking degree of the back pre-crosslinking film is 30% to 60%.

6. The photovoltaic module according to claim 5, characterized in that: The weight of the back pre-crosslinked film is 50 g / m 2 ~300g / m 2 The thickness of the back pre-crosslinked film is 0.1 mm to 0.3 mm.

7. The photovoltaic module according to claim 1, characterized in that: The material of the first pre-crosslinked film is polyolefin elastomer, ethylene-vinyl acetate copolymer or polyolefin elastomer and ethylene-vinyl acetate copolymer, and the material of the second pre-crosslinked film is polyolefin elastomer, ethylene-vinyl acetate copolymer or polyolefin elastomer and ethylene-vinyl acetate copolymer.

8. The photovoltaic module according to any one of claims 1 to 7, characterized in that: The photovoltaic module also includes a frame, which is sleeved around the periphery of a laminate consisting of the front glass, the second pre-cross-linked film, the first pre-cross-linked film, the battery cell, the back pre-cross-linked film, the back adhesive film and the back panel or the back glass.

9. A method for producing a photovoltaic module, characterized in that: include: Pre-crosslinking the first adhesive film, the second adhesive film and the third adhesive film to obtain a first pre-crosslinked film, a second pre-crosslinked film and a back pre-crosslinked film respectively; affixing a plurality of the first pre-crosslinked films to the front side of each battery cell, and affixing a plurality of the back side pre-crosslinked films to the back side of each battery cell, so that each battery cell is 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 the back glass are stacked from bottom to top to form a pre-laminated product; The pre-lamination product is laminated to form a laminate.

10. The production method according to claim 9, characterized in that: The production method further comprises: performing an electroluminescence test on the laminate; The laminate that has passed the electroluminescence test is framed to form a finished product of the photovoltaic module.

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