Photovoltaic module and photovoltaic module preparation method

Abstract

The invention discloses a photovoltaic module and a photovoltaic module preparation method, which are applied to the field of photovoltaic cells, and the photovoltaic module comprises a back plate, a back packaging adhesive film, a back carrier film, a photovoltaic cell layer, a front carrier film, a front packaging adhesive film and a front cover plate which are sequentially stacked, the photovoltaic cell layer comprises a plurality of cell pieces, solder strips for connecting adjacent cell pieces, and a back carrier film; the front carrier film is used for pre-fixing the solder strips to the surfaces of the cell pieces; the thermal expansion coefficient of the back plate is greater than that of the front cover plate; the back carrier film includes a thermoplastic polyolefin carrier film. The thermal expansion coefficient of the back plate is greater than the thermal expansion coefficient of the front cover plate, and the back carrier film comprises the thermoplastic polyolefin carrier film, so that the fixing stability of the carrier film on the welding strip can be improved, the problem of pseudo soldering between the welding strip and the electrode of the battery piece is avoided, and meanwhile, the water vapor erosion resistance of the assembly is improved; and therefore, the damp-heat resistance of the single-glass assembly is improved.

Description

Technical Field

[0001] This invention relates to the field of photovoltaic cells, and in particular to a photovoltaic module and a method for preparing a photovoltaic module. Background Technology

[0002] With the increasing severity of energy problems, developing new energy sources is the main way to solve current energy issues. Among them, the utilization and research of solar energy has attracted many companies and researchers. Since the beginning of the 21st century, my country's photovoltaic industry has entered a period of steady growth. In order to reduce costs, in recent years, the industry has publicly adopted a scheme to fix the solder ribbon to the surface of the grid-less cell using a carrier film. After the existing carrier film is laminated, it cross-links with the encapsulation film of the photovoltaic module. For single-glass modules, when the photovoltaic module experiences high and low temperature environmental changes, the difference in the thermal expansion coefficients between the front glass and the back sheet of the photovoltaic module is large, causing the back sheet to drive the encapsulation film of the photovoltaic module to shift. Because of the cross-linking between the carrier film and the encapsulation film, the carrier film deforms, which weakens the constraint of the carrier film on the solder ribbon, and even causes the constraint of the carrier film on the solder ribbon to disappear at the edge of the module, resulting in the problem of poor soldering at the edge of the photovoltaic module.

[0003] Therefore, how to provide a method that ensures the stability of the carrier film in a photovoltaic module under temperature changes, while also ensuring the aesthetics and light transmittance of the photovoltaic module, is a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0004] In view of this, the purpose of the present invention is to provide a photovoltaic module and a method for manufacturing a photovoltaic module, which solves the problem in the prior art that when a photovoltaic module is subjected to cyclic changes in high and low temperature environments, the back sheet causes the encapsulation film to shift, resulting in the back carrier film also shifting.

[0005] To address the aforementioned technical problems, the present invention provides a photovoltaic module, comprising:

[0006] The backplate, back sealing film, back carrier film, photovoltaic cell layer, front carrier film, front sealing film and front cover are stacked in sequence.

[0007] The photovoltaic cell layer includes a plurality of cells and solder ribbons connecting adjacent cells. The back carrier film and the front carrier film are used to pre-fix the solder ribbons to the surface of the cells.

[0008] The coefficient of thermal expansion of the back plate is greater than that of the front cover plate.

[0009] The back support film includes a thermoplastic polyolefin support film.

[0010] Optionally, the solar cell is a gridless solar cell.

[0011] Optionally, the thermoplastic polyolefin carrier film includes a substrate layer and a reflective layer.

[0012] Optionally, the matrix layer is prepared by weight of 60-80 parts polyolefin resin, 20-40 parts polyolefin elastomer resin, and other additives.

[0013] The reflective layer is prepared by weight of 90-100 parts of polyolefin elastomer resin, 0.1-2 parts of antioxidant and 0.1-2 parts of light stabilizer.

[0014] Optionally, the antioxidant includes one or more of amine antioxidants and thio-oxidants.

[0015] Optionally, the light stabilizer is a benzotriazole light stabilizer or a benzophenone light stabilizer.

[0016] Optionally, the ratio of the thickness of the reflective layer to the thickness of the substrate layer is 1:1.5 to 1:2.5.

[0017] Optionally, the thickness of the reflective layer is 0.03~0.05 mm, and the thickness of the substrate layer is 0.05~0.1 mm;

[0018] The overall thickness of the thermoplastic polyolefin carrier film is 0.08~0.13 mm.

[0019] Optionally, the reflective layer is white, or both the reflective layer and the substrate layer are white.

[0020] The present invention also provides a method for manufacturing photovoltaic modules, comprising:

[0021] A battery string is obtained by pre-fixing the solder ribbon to the surface of the battery cell using a back carrier film and a front carrier film, wherein the back carrier film includes a thermoplastic polyolefin carrier film;

[0022] The front film is laid on the front cover plate, and then several battery strings are arranged and laid on the front film to form a photovoltaic cell layer.

[0023] The back film and the back sheet are then sequentially placed on the photovoltaic cell layer. The coefficient of thermal expansion of the back sheet is greater than that of the front cover plate.

[0024] As can be seen, the photovoltaic module provided by the present invention includes a backsheet, a back encapsulating film, a back carrier film, a photovoltaic cell layer, a front carrier film, a front encapsulating film, and a front cover plate stacked sequentially. The photovoltaic cell layer includes a plurality of cells and solder ribbons connecting adjacent cells. The back carrier film and the front carrier film are used to pre-fix the solder ribbons to the surface of the cells. The thermal expansion coefficient of the backsheet is greater than that of the front cover plate. The back carrier film includes a thermoplastic polyolefin carrier film. Based on the difference in thermal expansion coefficients between the backsheet and the front cover plate, and the fact that the thermal expansion coefficient of the backsheet is greater than that of the front cover plate, the back carrier film is set to include a thermoplastic polyolefin carrier film. This avoids the problem that when the photovoltaic module undergoes cyclic high and low temperature changes, the backsheet causes the encapsulating film to shift, which in turn causes the back carrier film to shift as well. This improves the stability of the carrier film in fixing the solder ribbons, avoids the problem of poor soldering between the solder ribbons and the electrodes of the cells, and simultaneously improves the module's resistance to moisture erosion, thereby improving the single-glass module's resistance to damp heat.

[0025] In addition, the present invention also provides a method for preparing photovoltaic modules, which also has the above-mentioned beneficial effects. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in 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 embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0027] Figure 1 This is a schematic diagram of the structure of a photovoltaic module provided in an embodiment of the present invention;

[0028] Figure 2 This is a schematic diagram of another photovoltaic module provided in an embodiment of the present invention;

[0029] Figure 3 This is a schematic diagram of the structure of a conventional laminated photovoltaic module;

[0030] Figure 4 This is a schematic diagram of the structure of a photovoltaic module after lamination, provided in an embodiment of the present invention;

[0031] Figure 5 This is a schematic diagram of the structure of a thermoplastic polyolefin carrier film in a photovoltaic module provided by an embodiment of the present invention;

[0032] Figure 6 A flowchart illustrating a photovoltaic module fabrication method provided in an embodiment of the present invention;

[0033] The attached diagram is described below:

[0034] 10-Backsheet, 20-Backside encapsulating film, 30-Backside carrier film, 31-Substrate layer, 32-Reflective layer, 40-Photovoltaic cell layer, 50-Frontside carrier film, 60-Frontside encapsulating film, 70-Frontside cover plate, 80-Solder ribbon, 91-Cross-linked layer formed by laminating the backside carrier film and the backside encapsulating film, 92-Cross-linked layer formed by laminating the frontside carrier film and the frontside encapsulating film. Detailed Implementation

[0035] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only 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.

[0036] Example 1:

[0037] Please refer to Figure 1 , Figure 1 This is a schematic diagram of a photovoltaic module provided in an embodiment of the present invention. The photovoltaic module may include:

[0038] The backplate 10, the back sealing film 20, the back carrier film 30, the photovoltaic cell layer 40, the front carrier film 50, the front sealing film 60 and the front cover plate 70 are stacked in sequence.

[0039] The photovoltaic cell layer 40 includes a plurality of cells, a solder ribbon 80 connecting adjacent cells, a back carrier film 30, and a front carrier film 50 for pre-fixing the solder ribbon 80 to the surface of the cells.

[0040] The coefficient of thermal expansion of the back panel 10 is greater than that of the front cover 70.

[0041] The back carrier film 30 includes a thermoplastic polyolefin carrier film.

[0042] It should be noted that the specific stacking arrangement of the backplate 10, back sealing film 20, back carrier film 30, photovoltaic cell layer 40, front carrier film 50, front sealing film 60, and front cover plate 70 in this embodiment can refer to the stacking arrangement of existing photovoltaic modules. The three-dimensional structure of the photovoltaic module in this embodiment can also refer to... Figure 2 , Figure 2This is a schematic diagram of another photovoltaic module provided in an embodiment of the present invention. The back support film 30 and the front support film 50 are respectively disposed on the front and back sides of the photovoltaic cell layer 40. This embodiment is mainly applied to photovoltaic modules where the front cover plate 70 and the back sheet 10 have different coefficients of thermal expansion. Specifically, the coefficient of thermal expansion of the back sheet 10 is greater than that of the front cover plate 70. Because the coefficient of thermal expansion of the back sheet 10 of the photovoltaic module is greater than that of the front cover plate 70, during the process of high and low temperature cycling of the photovoltaic module, the back sheet 10 of the photovoltaic module causes the back encapsulation film 20 of the photovoltaic module to shift due to thermal expansion and contraction. When a carrier film is provided on the outside of the solder ribbon 80 laid on the surface of the cell, the existing carrier film and the encapsulation film are cross-linked during the lamination process. Therefore, the movement of the back encapsulation film 20 will also cause the back carrier film 30 to deform, resulting in a weakening of the constraint force of the back carrier film 30 on the solder ribbon 80. In some cases, the constraint force of the back carrier film 30 on the solder ribbon 80 may even disappear completely in the edge area of ​​the cell, leading to the problem of regular cold solder joints in the photovoltaic module. This embodiment addresses this issue by including a thermoplastic polyolefin carrier film 30 as the back carrier film 30. After lamination, this thermoplastic polyolefin carrier film does not cross-link with the adjacent encapsulating film. Therefore, the interface between the back encapsulating film 20 and the back carrier film 30 is independent after lamination. The deformation of the backsheet 10 during thermal expansion and contraction is released by the elasticity of the back encapsulating film 20. Since the back carrier film 30 does not cross-link with the back encapsulating film 20, the constraint force of the back carrier film 30 on the solder ribbon 80 remains stable, ensuring excellent thermal cycling resistance of the encapsulation structure. Existing laminated photovoltaic modules can be referenced. Figure 3 , Figure 3 This is a schematic diagram of the structure of a conventional laminated photovoltaic module. The cross-linked layer 91 is formed by laminating the back carrier film and the back encapsulating film, and the cross-linked layer 92 is formed by laminating the front carrier film and the front encapsulating film, as shown in the diagram. Figure 3 As shown in the figure. The laminated photovoltaic module in this embodiment can be referenced from... Figure 4 , Figure 4This is a schematic diagram of a laminated photovoltaic module according to an embodiment of the present invention. In this embodiment, the photovoltaic module only includes a cross-linked layer 92 formed by laminating the front carrier film and the front encapsulating film, while the back carrier film 30 includes a thermoplastic polyolefin carrier film, which can prevent cross-linking with the back encapsulating film 20. In this embodiment, the back carrier film 30 of the photovoltaic module is provided as a thermoplastic polyolefin carrier film. Since the thermoplastic polyolefin carrier film has low water permeability, it can protect the internal battery layer of the photovoltaic module from moisture corrosion, thereby improving the photovoltaic module's resistance to damp heat. In this embodiment, the application of the thermoplastic polyolefin carrier film is not limited to one side. Preferably, it can be placed on the back side. However, with technological advancements, since there is no color difference between the thermoplastic polyolefin carrier film and other structures after lamination, both the front carrier film 50 and the back carrier film 30 of the photovoltaic module can include the thermoplastic polyolefin carrier film. Therefore, only the back carrier film 30 can include the thermoplastic polyolefin carrier film. It should be noted that this embodiment can be applied to single-sided photovoltaic modules. In this embodiment, because the materials and additives added between the thermoplastic polyolefin carrier film and the adjacent encapsulating film are not... One issue arises because the thermoplastic polyolefin carrier film requires the addition of resin materials. Therefore, after module lamination, a color difference occurs between the thermoplastic polyolefin carrier film and the solar cell or adjacent encapsulating film. When this thermoplastic polyolefin carrier film is placed on the front side of the solar cell, it affects both the aesthetics of the photovoltaic module and the sunlight incident from the front side of the solar cell, reducing the photovoltaic module's photoelectric conversion efficiency. This embodiment solves this problem by having only the back carrier film 30 include a thermoplastic polyolefin carrier film, applied to a single-sided photovoltaic module. Furthermore, in this embodiment, when only the back carrier film 30 includes a thermoplastic polyolefin carrier film, the front carrier film 50 can include at least one of an EVA (ethylene-vinyl acetate copolymer) carrier film and a POE (polyolefin elastomer) carrier film. In one specific embodiment, a conventional carrier film is used as a control group, while in this embodiment, the back carrier film 30 is set as a thermoplastic polyolefin carrier film as an example group. The test parameters are as follows: In the carrier film of the control group, the basis weight of the carrier film is 100 g / m², and the performance degradation is less than 4% during the damp heat resistance test. In the carrier film of the example group, the basis weight of the carrier film is 80 g / m², and the performance degradation is less than 3% during the damp heat resistance test. It can be seen that the thermoplastic polyolefin carrier film provided in this embodiment has better damp heat resistance.

[0043] This embodiment can be applied to single-sided photovoltaic modules, and more specifically, to single-glass photovoltaic modules. In this case, the front cover plate 70 is the front glass cover plate, and the specific material of the back sheet 10 is not limited, as long as it has a large difference in thermal expansion coefficient with the front glass cover plate and its thermal expansion coefficient is greater than that of the front glass cover plate. For example, the back sheet 10 can be set as a CPC type back sheet, or it can be set as a TPC type back sheet. It should be further noted that in this embodiment, the CPC type back sheet is a laminated structure formed by using a PET (polyethylene terephthalate) film layer as the substrate layer and coating both sides of the PET film layer with a fluorinated resin. The fluorinated resin can be set as PVDF (polyvinylidene fluoride) or PTFE (polytetrafluoroethylene), etc. The TPC type back sheet mentioned in this embodiment is a laminated structure formed by PVF (polyvinylidene fluoride) on the outside of the module and a PET substrate layer on the inside of the module. In this embodiment, the solder ribbons 80 set between the front carrier film 50 and the back carrier film 30 and the photovoltaic cell layer 40 can both be set as low-temperature solder ribbons. This embodiment can be specifically applied to gridless photovoltaic modules, where the solder ribbon 80 is fixed to the surface of the corresponding solar cell using the front carrier film 50 and the back carrier film 30. Furthermore, in this embodiment, the back carrier film 30, being a thermoplastic polyolefin carrier film, reduces the interfacial bonding force with the back encapsulation film 20. This thermoplastic polyolefin carrier film also exhibits low fluidity, high thermal stress resistance, and good adhesion to the solar cell, thereby reducing the risk of cell breakage. Therefore, while ensuring the yield of the photovoltaic module, the thickness of the solar cell can be adaptively reduced. For example, the thickness of a single solar cell in this embodiment can be less than 130 micrometers, thus reducing the overall thickness of the photovoltaic module. Specifically, this embodiment can be configured as a gridless TOPCon (tunneling oxide passivated contact) single-glass photovoltaic module.

[0044] Furthermore, in order to ensure the light transmittance of the photovoltaic module in this embodiment, and thus ensure the photoelectric conversion efficiency of the photovoltaic module, the above-mentioned solar cell can be set as a gridless solar cell.

[0045] In this embodiment, the above-mentioned solar cell is set as a gridless solar cell, which can improve the light collection efficiency of the solar cell and thus improve the photoelectric conversion efficiency of the solar cell.

[0046] The photovoltaic module provided by the embodiments of the present invention includes a backsheet 10, a back sealing film 20, a back carrier film 30, a photovoltaic cell layer 40, a front carrier film 50, a front sealing film 60, and a front cover plate 70 stacked sequentially. The photovoltaic cell layer includes a plurality of cells and solder ribbons 80 connecting adjacent cells. The back carrier film 30 and the front carrier film 50 are used to pre-fix the solder ribbons 80 to the surface of the cells. The coefficient of thermal expansion of the backsheet 10 is greater than that of the front cover plate 70. The back carrier film 30 includes a thermoplastic polyolefin carrier film. In this invention, based on the difference in thermal expansion coefficients between the backsheet 10 and the front cover 70 (specifically, the thermal expansion coefficient of the backsheet 10 is greater than that of the front cover 70), the back support film 30 is made of thermoplastic polyolefin. This avoids the problem that when the photovoltaic module undergoes cyclic high and low temperature changes, the backsheet 10 causes the encapsulation film to shift, which in turn causes the back support film 30 to shift as well. This improves the stability of the support film in pre-fixing the solder ribbon 80, avoids the problem of poor soldering between the solder ribbon 80 and the electrode of the cell, and improves the module's resistance to moisture erosion, thereby improving the single-glass module's resistance to damp heat.

[0047] Furthermore, by configuring the aforementioned solar cell as a gridless solar cell, the light-gathering efficiency of the solar cell can be improved, thereby increasing the photoelectric conversion efficiency of the solar cell.

[0048] In other embodiments of the present invention, reference may be made to Figure 5 , Figure 5 This is a schematic diagram of the structure of a thermoplastic polyolefin carrier film in a photovoltaic module provided by an embodiment of the present invention. The thermoplastic polyolefin carrier film includes a substrate layer 31 and a reflective layer 32.

[0049] It should be noted that in this embodiment, the thermoplastic polyolefin carrier film includes a substrate layer 31 and a reflective layer 32. Specifically, a reflective layer 32 is formed on one side of the thermoplastic polyolefin carrier film to enhance light beam reflection. This enhanced light beam reflection surface is specifically located on the side of the thermoplastic polyolefin carrier film facing the photovoltaic cell layer 40. This allows light beams that have passed over the solar cell and struck the surface of the thermoplastic polyolefin carrier film to be reflected back to the surface of the solar cell, further improving the photoelectric conversion efficiency of the photovoltaic module. This embodiment does not limit the specific manner in which the reflective layer 32 is set, as long as it can improve the reflectivity of the light beam.

[0050] Furthermore, in order to ensure the functionality of the thermoplastic polyolefin carrier film, the substrate layer 31 is prepared by weight of 60-80 parts of polyolefin resin, 20-40 parts of polyolefin elastomer resin, and other additives.

[0051] The reflective layer 32 is prepared by weight of 90-100 parts of polyolefin elastomer resin, 0.1-2 parts of antioxidant and 0.1-2 parts of light stabilizer.

[0052] It should be noted that in this embodiment, the substrate layer 31 is disposed on the thermoplastic polyolefin carrier film, facing the adjacent encapsulating film, while the reflective layer 32 is disposed on the side facing the photovoltaic cell layer 40. This ensures that the thermoplastic polyolefin carrier film reflects sunlight across the solar cell back to the solar cell. Furthermore, in this embodiment, polyolefin resin is the main material of the substrate layer 31, while polyolefin elastomer resin is the main material of the reflective layer 32. The thermoplastic polyolefin carrier film prepared by the manufacturing ratio of the substrate layer 31 and the reflective layer 32 in this embodiment ensures the stability and high reflectivity of the carrier film, guaranteeing the functionality of the photovoltaic module.

[0053] Furthermore, in order to ensure the successful preparation of the reflective layer 32, the antioxidants mentioned above may include one or more of amine antioxidants and thio-oxidants.

[0054] In this embodiment, when the antioxidant is set as an ammonia-based antioxidant, its strong ability to scavenge peroxide free radicals effectively prevents oxidation. Furthermore, the stability of ammonia-based antioxidants at high temperatures broadens their application scenarios. When the antioxidant is set as a thio-based antioxidant, it can decompose peroxides and also function as an auxiliary antioxidant. Therefore, to improve the functionality of the antioxidant, it is possible to include both ammonia-based and thio-based antioxidants.

[0055] Furthermore, in order to ensure the functional stability of the prepared reflective layer 32, and thus the structural stability of the final thermoplastic polyolefin carrier film, the light stabilizer can be set to a benzotriazole light stabilizer or a benzophenone light stabilizer.

[0056] In this embodiment, the benzotriazole light stabilizer and the benzophenone light stabilizer have high UV absorption capacity, good thermal and chemical stability, compatibility with polymer materials, environmental friendliness and safety, and can improve the functional stability of the prepared reflective layer 32.

[0057] Furthermore, in a feasible embodiment, in order to realize the functionality of the thermoplastic polyolefin carrier film, the thickness ratio of the reflective layer 32 to the substrate layer 31 can be set to 1:1.5 to 1:2.5.

[0058] Furthermore, in a feasible embodiment, the specific thickness between the layers in the above-mentioned thermoplastic polyolefin carrier film can be set as follows:

[0059] The thickness of the reflective layer 32 is 0.03~0.05 mm, and the thickness of the substrate layer 31 is 0.05~0.1 mm;

[0060] The thickness of the thermoplastic polyolefin carrier film is 0.08~0.13 mm.

[0061] It should be noted that, in this embodiment, the ratio of the thickness of the reflective layer 32 to the thickness of the substrate layer 31 needs to meet the range of 1:1.5 to 1:2.5.

[0062] Furthermore, in order to improve the ease of preparation of the thermoplastic polyolefin carrier film while achieving the reflective effect of the thermoplastic polyolefin carrier film on the light beam, the reflective layer 32 can be set to be white, or both the reflective layer 32 and the substrate layer 31 can be set to be white.

[0063] In this embodiment, by setting the reflective layer 32 to white, or by setting both the reflective layer 32 and the substrate layer 31 to white, the reflectivity of the carrier film can be achieved. Furthermore, by setting both the reflective layer 32 and the substrate layer 31 to white, the ease of preparation of the carrier film can be ensured.

[0064] The photovoltaic module provided in this embodiment of the invention uses a thermoplastic polyolefin carrier film comprising a substrate layer 31 and a reflective layer 32 to ensure that a reflective layer 32 that enhances light beam reflection can be formed on one side surface of the thermoplastic polyolefin carrier film. Specifically, the reflective layer 32 is set as the side surface of the thermoplastic polyolefin carrier film facing the photovoltaic cell layer 40, so as to reflect the light beam that passes over the cell and illuminates the surface of the thermoplastic polyolefin carrier film back to the surface of the cell, thereby further improving the photoelectric conversion efficiency of the photovoltaic module.

[0065] Furthermore, the thermoplastic polyolefin carrier film prepared by utilizing the manufacturing ratio of the substrate layer 31 and the reflective layer 32 in this embodiment of the invention can ensure the stability and reflective effect of the carrier film, thus guaranteeing the functionality of the photovoltaic module; by setting antioxidants including one or more of amine antioxidants and thiolated antioxidants, the successful preparation of the reflective layer 32 can be ensured; by setting the light stabilizer as a benzotriazole light stabilizer or a benzophenone light stabilizer, the ultraviolet absorption capacity, good thermal and chemical stability, compatibility with polymer materials, environmental friendliness, and safety of the reflective layer 32 are achieved; The thickness ratio of the reflective layer 32 to the substrate layer 31 is 1:1.5 to 1:2.5, which enables the functionality of the thermoplastic polyolefin carrier film. Setting the thickness of the reflective layer 32 to 0.03 to 0.05 mm, the substrate layer 31 to 0.05 to 0.1 mm, and the thermoplastic polyolefin carrier film to 0.08 to 0.13 mm ensures the functionality of the thermoplastic polyolefin carrier film and its layers. By setting the reflective layer 32 to be white, or both the reflective layer 32 and the substrate layer 31 to be white, the high reflectivity of the carrier film is achieved, while ensuring the ease of preparation of the carrier film.

[0066] In one feasible embodiment, this embodiment provides a grid-free single-glass photovoltaic module, which may specifically include the following structure:

[0067] The back sheet, back sealing film, back carrier film, photovoltaic cell layer, front carrier film, front sealing film and front glass cover are stacked in sequence.

[0068] The photovoltaic cell layer includes several cells, solder ribbons connecting adjacent cells, a back carrier film, and a front carrier film for pre-fixing the solder ribbons to the surface of the cells;

[0069] The coefficient of thermal expansion of the back panel is greater than that of the front glass cover; the solar cells are gridless solar cells.

[0070] The back support film is a thermoplastic polyolefin support film; the thermoplastic polyolefin support film includes a matrix layer and a reflective layer. The matrix layer, by weight, is prepared from 60-80 parts of polyolefin resin, 20-40 parts of polyolefin elastomer resin, and other additives. The reflective layer, by weight, is prepared from 90-100 parts of polyolefin elastomer resin, 0.1-2 parts of antioxidant, and 0.1-2 parts of light stabilizer. The antioxidants include amine antioxidants and thio-oxidants, and the light stabilizers are benzotriazole light stabilizers or benzophenone light stabilizers.

[0071] The ratio of the thickness of the reflective layer to the thickness of the substrate layer is 1:1.5 to 1:2.5, and the thickness of the reflective layer is 0.03 to 0.05 mm, the thickness of the substrate layer is 0.05 to 0.1 mm, and the thickness of the thermoplastic polyolefin carrier film is 0.08 to 0.13 mm.

[0072] The reflective layer is set to white, or both the reflective layer and the substrate layer are set to white.

[0073] The following describes a method for preparing a photovoltaic module according to an embodiment of the present invention. The photovoltaic module preparation method described below can be referred to in correspondence with the photovoltaic module described above.

[0074] Please refer to the details. Figure 6 , Figure 6 A flowchart of a photovoltaic module fabrication method provided in this embodiment of the invention, the method may include:

[0075] S101: The welding ribbon is pre-fixed to the surface of the battery cell using a back carrier film and a front carrier film to obtain a battery string, wherein the back carrier film includes a thermoplastic polyolefin carrier film.

[0076] In this embodiment, the battery preform is typically fabricated simultaneously with a battery string. Specifically, a back support film is first laid, and solder ribbons are then applied to this back support film. The back support film is then used to pre-fix the solder ribbons to the back of the target battery cell. Next, solder ribbons are prepared to be laid on the front of the target battery cell. However, it should be noted that since adjacent battery cells in the fabricated battery string are interconnected via solder ribbons, a back support film needs to be laid at an adjacent location on the front of the target battery cell before the solder ribbons are laid on the front of the target battery cell. A solder ribbon is laid on the front side of the target solar cell, extending to the back carrier film laid at an adjacent location. The solder ribbon is then pre-fixed to the front side of the target solar cell using the front carrier film. At this point, another solar cell is connected to the back carrier film where the solder ribbon is laid at an adjacent location, serving as a new target solar cell. This process is repeated until the last solar cell in the same cell string is prepared. At this point, the solder ribbon is connected to the last solar cell using the back carrier film, and then solder ribbons are directly prepared on the front side of the last solar cell, and the front carrier film is fixed, completing the cell string preparation. However, it should be noted that the above preparation method is only an example of the preparation method for solar cell preforms and can be modified according to actual conditions during actual preparation. S102: A front adhesive film is laid on the front cover plate, and several cell strings are arranged and laid on the front adhesive film to form a photovoltaic cell layer.

[0077] Currently, photovoltaic modules are typically manufactured with the front side of the solar cells facing down. Therefore, the front cover and the front encapsulant film are prepared first.

[0078] S103: Then, the back film and the back sheet are sequentially placed on the photovoltaic cell layer. The thermal expansion coefficient of the back sheet is greater than that of the front cover plate.

[0079] In this embodiment, the back carrier film is a thermoplastic polyolefin carrier film, which ensures that the constraint force of the back carrier film on the solder ribbon remains stable during the preparation process, thereby ensuring the heat resistance of the packaging structure.

[0080] The photovoltaic module manufacturing method provided in this invention includes S101: using a back carrier film and a front carrier film to pre-fix the solder ribbon to the surface of the cell to obtain a cell string, wherein the back carrier film includes a thermoplastic polyolefin carrier film; S102: laying a front adhesive film on a front cover plate, and then arranging and laying several cell strings on the front adhesive film to form a photovoltaic cell layer; S103: then sequentially setting the back adhesive film and the back sheet on the photovoltaic cell layer, wherein the thermal expansion coefficient of the back sheet is greater than that of the front cover plate. In this invention, based on the difference in thermal expansion coefficients between the back sheet and the front cover plate, and the fact that the thermal expansion coefficient of the back sheet is greater than that of the front cover plate, the back carrier film is made of thermoplastic polyolefin. This avoids the problem that when the photovoltaic module undergoes cyclic high and low temperature changes, the back sheet causes the encapsulation film to shift, leading to the displacement of the back carrier film as well. This improves the stability of the carrier film in fixing the solder ribbon, avoids the problem of poor soldering between the solder ribbon and the cell electrodes, and simultaneously improves the module's resistance to moisture erosion, thereby improving the single-glass module's resistance to damp heat.

[0081] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since it corresponds to the method disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to in the method section.

[0082] Furthermore, it should be noted that in this document, relationships 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. Moreover, the terms "comprising," "including," or any other variations are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0083] The present invention has provided a detailed description of a photovoltaic module and a method for preparing the photovoltaic module. Specific examples have been used to illustrate the principle and implementation of the present invention. The description of the above embodiments is only for the purpose of helping to understand the method and core idea of ​​the present invention. At the same time, for those skilled in the art, there will be changes in the specific implementation and application scope based on the idea of ​​the present invention. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A photovoltaic module, characterized in that, include: The backplate, back sealing film, back carrier film, photovoltaic cell layer, front carrier film, front sealing film and front cover are stacked in sequence. The photovoltaic cell layer includes a plurality of cells and solder ribbons connecting adjacent cells. The back carrier film and the front carrier film are used to pre-fix the solder ribbons to the surface of the cells. The coefficient of thermal expansion of the back plate is greater than that of the front cover plate. The back support film includes a thermoplastic polyolefin support film.

2. The photovoltaic module according to claim 1, characterized in that, The solar cell is a gridless solar cell.

3. The photovoltaic module according to claim 1, characterized in that, The thermoplastic polyolefin carrier film includes a matrix layer and a reflective layer.

4. The photovoltaic module according to claim 3, characterized in that, The matrix layer is prepared by weight of 60-80 parts polyolefin resin, 20-40 parts polyolefin elastomer resin, and other additives. The reflective layer is prepared by weight of 90-100 parts of polyolefin elastomer resin, 0.1-2 parts of antioxidant and 0.1-2 parts of light stabilizer.

5. The photovoltaic module according to claim 4, characterized in that, The antioxidants include one or more of ammonia-based antioxidants and thio-based antioxidants.

6. The photovoltaic module according to claim 4, characterized in that, The light stabilizer is a benzotriazole light stabilizer or a benzophenone light stabilizer.

7. The photovoltaic module according to claim 4, characterized in that, The ratio of the thickness of the reflective layer to the thickness of the substrate layer is 1:1.5 to 1:2.

5.

8. The photovoltaic module according to claim 7, characterized in that, The thickness of the reflective layer is 0.03~0.05 mm, and the thickness of the substrate layer is 0.05~0.1 mm; The overall thickness of the thermoplastic polyolefin carrier film is 0.08~0.13 mm.

9. The photovoltaic module according to claim 3, characterized in that, The reflective layer is white, or both the reflective layer and the substrate layer are white.

10. A method for manufacturing a photovoltaic module, characterized in that, include: A battery string is obtained by pre-fixing the solder ribbon to the surface of the battery cell using a back carrier film and a front carrier film, wherein the back carrier film includes a thermoplastic polyolefin carrier film; The front film is laid on the front cover plate, and then several battery strings are arranged and laid on the front film to form a photovoltaic cell layer. The back film and the back sheet are then sequentially placed on the photovoltaic cell layer. The coefficient of thermal expansion of the back sheet is greater than that of the front cover plate.

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