Backsheet, method of making the same, and photovoltaic module

Abstract

The application provides a back plate, a preparation method thereof and a photovoltaic module, relates to the photovoltaic technical field, and the back plate is used for the photovoltaic module, and the back plate comprises a basalt fiber layer and a resin layer, wherein the basalt fiber layer is at least two layers, and the resin layer is arranged between the two basalt fiber layers, or the resin layer is at least two layers, and the basalt fiber layer is arranged between the two resin layers. The basalt fiber layer and the resin layer provided by the application are arranged alternately, and in the case of the same thickness, the heat insulation and compression resistance effect is higher than that of the conventional scheme of one layer of basalt fiber layer superimposed on one layer of resin layer.

Description

Technical Field

[0001] This invention relates to the field of photovoltaic technology, and more specifically, to a backsheet, its preparation method, and a photovoltaic module. Background Technology

[0002] Currently, some documents disclose the use of resin-basalt fiber composite materials for the frame of photovoltaic modules to improve frame performance. Additionally, some materials disclose the use of resin-basalt fiber composite materials as the front panel of photovoltaic modules. However, commonly used resin-basalt fiber composite materials typically consist of one layer of resin and one layer of basalt fiber, resulting in generally poor thermal insulation and compressive strength. Summary of the Invention

[0003] The present invention aims to solve at least one of the technical problems existing in the prior art or related art.

[0004] Therefore, the first aspect of the present invention provides a backplate.

[0005] A second aspect of the present invention provides a photovoltaic module.

[0006] A third aspect of the present invention provides a method for preparing a backplate.

[0007] The backsheet provided in the first aspect of the present invention is used for photovoltaic modules. The backsheet includes: a basalt fiber layer; a resin layer, wherein the basalt fiber layer is at least two layers and the resin layer is disposed between the two basalt fiber layers, or the resin layer is at least two layers and the basalt fiber layer is disposed between the two resin layers.

[0008] The alternating basalt fiber and resin layers provided by this invention offer superior thermal insulation and compressive strength compared to conventional solutions using a single layer of basalt fiber and a single layer of resin, while maintaining the same thickness. Specifically, the alternating backplate structure restricts vertical heat conduction and disrupts heat flow paths through the different thermal expansion coefficients of each layer, resulting in superior thermal insulation. Furthermore, in applications with high temperatures or extreme temperature variations, this design reduces the risk of thermal stress and structural damage. In addition, the alternation of different materials increases the damping capacity of the backplate, helping to reduce vibration and noise transmission, which is particularly important in applications requiring reduced noise and vibration.

[0009] In some embodiments, optionally, the number of resin layers is greater than or equal to 2 and less than or equal to 3; the number of basalt fiber layers is greater than or equal to 2 and less than or equal to 3, and the basalt fiber layers and resin layers are alternately arranged.

[0010] In this embodiment, the resin layer can be 2 or 3 layers, and the basalt fiber layer can be 2 or 3 layers. The basalt fiber layer and the resin layer are alternately arranged so that too many layers will result in a large weight and an insignificant lifting effect, and too few layers will not reduce the heat insulation and pressure resistance effect.

[0011] In some embodiments, optionally, the mass percentage of the basalt fiber layer to the backsheet is greater than or equal to 5% and less than or equal to 55%; the mass percentage of the resin layer to the backsheet is greater than or equal to 45% and less than or equal to 95%.

[0012] In this embodiment, controlling the mass ratio of the basalt fiber layer and the resin layer can ensure that the basalt fiber layer and the resin layer have good bonding force, while also ensuring that the backing plate has excellent properties such as high strength, high modulus, high temperature resistance, and acid and alkali resistance.

[0013] In some embodiments, optionally, the mass percentage of the basalt fiber layer to the backsheet is greater than or equal to 20% and less than or equal to 30%, for example, 20%, 25%, or 30%; and the mass percentage of the resin layer to the backsheet is greater than or equal to 70% and less than or equal to 80%, for example, 70%, 75%, or 80%.

[0014] In some embodiments, the basalt fiber layer may optionally comprise basalt fiber cloth.

[0015] In this embodiment, the basalt fiber cloth has better compatibility with the resin and exhibits better shear strength and compressive strength.

[0016] In some embodiments, the basalt fiber layer may optionally include basalt fiber cloth, wherein the weight of each cubic meter of basalt fiber cloth is greater than or equal to 100g and less than or equal to 700g.

[0017] In this embodiment, the weight of each cubic meter of basalt fiber cloth is greater than or equal to 100g and less than or equal to 700g, for example, 300g, 400g or 500g, which can ensure the high strength, high modulus, high temperature resistance and acid and alkali resistance of the backing plate.

[0018] In some embodiments, the fiber diameter of the basalt fiber layer is optionally greater than or equal to 9 μm and less than or equal to 16 μm.

[0019] In this embodiment, excessively large fiber diameters in the basalt fiber layer may reduce the strength and stiffness of the composite material because the smaller surface area of ​​the fibers reduces the bonding area with the resin, thus affecting the stress transfer between the fibers and the resin. Conversely, excessively small fiber diameters may lead to poor dispersion in the resin matrix, thereby affecting the overall performance of the composite material. Therefore, a fiber diameter of 9 μm to 16 μm is preferred for the basalt fiber layer, for example, 10 μm, 12 μm, 14 μm, or 16 μm.

[0020] In some embodiments, the resin layer may optionally include one or a combination of the following: a vinyl resin layer, a phenolic resin layer, an epoxy resin layer, and a polyester resin layer.

[0021] In this embodiment, different resins combined with basalt fibers can achieve different properties and effects, and the selection is based on actual requirements. Vinyl resin has good processing performance and room temperature curing performance, while also possessing the mechanical properties, toughness, and corrosion resistance of epoxy resin. Epoxy resin exhibits better shear and compressive strength due to its optimal compatibility with basalt fibers. Phenolic resin composite basalt fiber cloth has better thermal stability and abrasion resistance.

[0022] A second aspect of the present invention provides a photovoltaic module, comprising: a backsheet as provided in any embodiment of the first aspect of the present invention. Since the photovoltaic module provided by the present invention includes the backsheet provided in any embodiment of the first aspect of the present invention, it possesses all the beneficial effects of the backsheet provided in any embodiment of the first aspect of the present invention.

[0023] In some embodiments, the photovoltaic module may optionally further include: a panel; a front panel disposed on one side of the panel; a cell disposed on the side of the front panel away from the panel, and a back panel disposed on the side of the cell away from the front panel; and a mounting plate disposed on the side of the back panel away from the cell.

[0024] In this embodiment, the photovoltaic module, from top to bottom, includes a panel, a front panel, cells, a back panel, and a mounting plate. The basalt fiber-resin composite back panel layer of this invention provides excellent support for the cells, preventing damage from external forces. It should be understood that in conventional photovoltaic modules, solar cells are easily damaged by prolonged high temperatures. This invention improves the back panel, providing heat insulation for the cells and ensuring their safe operation.

[0025] In some embodiments, the panel may optionally include one or a combination of the following: PVDF (Polyvinylidenefluoride) sheet, PVF (Polyvinylidene fluoride) sheet, and ETFE (ethylene tetrafluoroethylene) sheet.

[0026] In this embodiment, PVDF, PVF, and ETFE all have good chemical corrosion resistance, high temperature resistance, oxidation resistance, weather resistance, and radiation resistance, making them suitable for use as panels in photovoltaic modules.

[0027] In some embodiments, the front panel may optionally include one or a combination of the following: PET (Polyethylene Terephthalate) sheet and EPE (Expandable Polyethylene) sheet.

[0028] In this embodiment, PET possesses excellent physical and mechanical properties, chemical resistance, optical properties, and electrical properties, making it suitable as a front-sheet material for photovoltaic modules. PET has high light transmittance, effectively transmitting sunlight and improving the power generation efficiency of photovoltaic modules. Furthermore, PET has good weather resistance, allowing it to be used in harsh environmental conditions and extending the lifespan of photovoltaic modules. EPE has excellent cushioning, thermal insulation, and moisture-proof properties, making it also a suitable front-sheet material for photovoltaic modules. EPE effectively protects photovoltaic modules from impacts and vibrations, improving their reliability. Additionally, EPE's thermal insulation properties effectively reduce the temperature of photovoltaic modules, further enhancing their power generation efficiency.

[0029] In some embodiments, the battery may optionally include one or a combination of the following: PERC (Passivated Emitter Rear Cell) battery, TOPcon (Top Emitting Contact) battery, and IBC (Interdigitated Back Contact) battery.

[0030] In this embodiment, PERC cells, TOPcon cells, and IBC cells all have long photoelectric conversion lifetimes and low power decay.

[0031] In some embodiments, the mounting plate may optionally include one or a combination of the following: PVDF (Polyvinylidene fluoride) plate, PVF (Polyvinyl formal) plate, and ETFE (Ethylene tetrafluoroethylene) plate.

[0032] In this embodiment, PVDF, PVF, and ETFE boards all possess excellent weather resistance, corrosion resistance, and chemical stability, thus providing excellent protection during the installation of photovoltaic modules. They can effectively prevent photovoltaic modules from being affected by environmental factors such as ultraviolet radiation, rain, and temperature changes, thereby improving the service life and performance of photovoltaic modules.

[0033] In some embodiments, the photovoltaic module may optionally further include: a first adhesive layer disposed between the panel and the front panel; a second adhesive layer disposed between the front panel and the cell; a third adhesive layer disposed between the cell and the back panel; and a fourth adhesive layer disposed between the back panel and the mounting plate.

[0034] In this embodiment, the overall stability of the photovoltaic module can be improved by setting an adhesive layer between the panel, front panel, cell, back panel and mounting plate.

[0035] In some embodiments, the first adhesive layer, the second adhesive layer, the third adhesive layer, and the fourth adhesive layer may optionally include one or a combination of the following: an EVA (Ethylene vinyl acetate copolymer) layer, a POE (Poly olefin elastomer) layer, and an EVA-POE composite layer.

[0036] In this embodiment, both the EVA layer and the POE layer have excellent connectivity, which improves the overall stability of the photovoltaic module.

[0037] A second aspect of the present invention provides a method for preparing a backsheet, comprising: preparing a resin solution; applying the resin solution to one side of basalt fibers to obtain a composite material; stacking multiple composite materials, wherein the resin solution layer and the basalt fiber layer are spaced apart; and pressing the multiple composite materials together by lamination to form a backsheet.

[0038] The backsheet preparation method provided by this invention, which alternates between basalt fiber layers and resin layers, offers superior thermal insulation and compressive strength compared to conventional methods that use a single layer of basalt fiber layer superimposed with a single layer of resin layer, while maintaining the same thickness. Specifically, the alternating backsheet structure limits vertical heat conduction and disrupts heat flow paths through the different thermal expansion coefficients of each layer, resulting in better thermal insulation. Furthermore, in applications involving high temperatures or extreme temperature variations, this design reduces the risk of thermal stress and structural damage. In addition, the alternating use of different materials increases the damping capacity of the backsheet, helping to reduce vibration and noise transmission, which is particularly important in applications requiring reduced noise and vibration.

[0039] In some embodiments, the basalt fiber may optionally include basalt fiber cloth, and the preparation method of the backing plate may further include: sequentially crushing, melting, drawing, and impregnating basalt ore with a sizing agent to obtain basalt fiber filaments; and weaving the basalt fiber filaments to obtain basalt fiber cloth.

[0040] In this embodiment, basalt ore can be sequentially crushed, melted, drawn into fibers, and impregnated with a sizing agent to obtain basalt fiber filaments; the basalt fiber filaments are then woven to obtain basalt fiber cloth. Basalt fiber cloth exhibits better compatibility with resin and demonstrates superior shear strength and compressive strength.

[0041] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0042] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0043] Figure 1 A schematic diagram of the structure of the back plate according to an embodiment of the present invention is shown;

[0044] Figure 2 A diagram of a basalt fiber cloth and resin composite backing plate according to an embodiment of the present invention is shown.

[0045] Figure 3 A schematic diagram of the structure of a photovoltaic module according to an embodiment of the present invention is shown;

[0046] Figure 4 A comparison graph showing the change in fracture strength of basalt fiber and glass fiber with temperature is shown;

[0047] Figure 5 One of the flowcharts for a method of preparing a backplate according to an embodiment of the present invention is shown;

[0048] Figure 6The second schematic flowchart illustrates a method for preparing a backplate according to an embodiment of the present invention.

[0049] in, Figures 1 to 3 The correspondence between the reference numerals and component names in the attached drawings is as follows:

[0050] 1. Photovoltaic module, 11. Panel, 12. First adhesive layer, 13. Front panel, 14. Second adhesive layer, 15. Cell, 16. Third adhesive layer, 17. Backsheet, 17.2. Basalt fiber layer, 17.4. Resin layer, 18. Fourth adhesive layer, 19. Mounting plate. Detailed Implementation

[0051] To better understand the above-mentioned objectives, features, and advantages of this application, the application will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that, unless otherwise specified, the embodiments and features described in these embodiments can be combined with each other.

[0052] Many specific details are set forth in the following description in order to provide a full understanding of this application. However, this application may also be implemented in other ways different from those described herein. Therefore, the scope of protection of this application is not limited to the specific embodiments disclosed below.

[0053] like Figure 1 As shown, a first aspect of the present invention provides a backsheet 17 for a photovoltaic module 1. The backsheet 17 includes a basalt fiber layer 172 and a resin layer 174, wherein the basalt fiber layer 172 is at least two layers and the resin layer 174 is disposed between the two basalt fiber layers 172, or the resin layer 174 is at least two layers and the basalt fiber layer 172 is disposed between the two resin layers 174.

[0054] The basalt fiber layer 172 and resin layer 174 alternately arranged in this invention provide superior thermal insulation and compressive strength compared to conventional solutions that use a single layer of basalt fiber layer 172 superimposed with a single layer of resin layer 174, while maintaining the same thickness. Specifically, the alternating backplate 17 structure restricts vertical heat conduction and disrupts heat flow paths through the different thermal expansion coefficients of each layer, resulting in better thermal insulation. Furthermore, in applications with high temperatures or extreme temperature variations, this design reduces the risk of thermal stress and structural damage. In addition, the alternating use of different materials increases the damping capacity of the backplate 17, helping to reduce vibration and noise transmission, which is particularly important in applications requiring reduced noise and vibration.

[0055] In some embodiments, optionally, the number of resin layers 174 is greater than or equal to 2 and less than or equal to 3; the number of basalt fiber layers 172 is greater than or equal to 2 and less than or equal to 3, and the basalt fiber layers 172 and resin layers 174 are alternately arranged.

[0056] In this embodiment, the resin layer 174 can be 2 or 3 layers, the basalt fiber layer 172 can be 2 or 3 layers, and the basalt fiber layer 172 and the resin layer 174 are alternately arranged. This way, too many layers will result in a large gravity and an insignificant lifting effect, while too few layers will reduce the heat insulation and pressure resistance.

[0057] In some embodiments, optionally, the mass percentage of the basalt fiber layer 172 to the back plate 17 is greater than or equal to 5% and less than or equal to 55%; the mass percentage of the resin layer 174 to the back plate 17 is greater than or equal to 45% and less than or equal to 95%.

[0058] In this embodiment, controlling the mass ratio of basalt fiber layer 172 and resin layer 174 can ensure that basalt fiber layer 172 and resin layer 174 have good bonding force, and at the same time ensure that the back plate 17 has excellent properties such as high strength, high modulus, high temperature resistance, and acid and alkali resistance.

[0059] In some embodiments, optionally, the mass percentage of the basalt fiber layer 172 to the mass percentage of the backing plate 17 is greater than or equal to 20% and less than or equal to 30%, for example, 20%, 25% or 30%; and the mass percentage of the resin layer 174 to the mass percentage of the backing plate 17 is greater than or equal to 70% and less than or equal to 80%, for example, 70%, 75% or 80%.

[0060] In some embodiments, optionally, such as Figure 2 As shown, the basalt fiber layer 172 includes basalt fiber cloth.

[0061] In this embodiment, the basalt fiber cloth has better compatibility with the resin and exhibits better shear strength and compressive strength.

[0062] In some embodiments, the basalt fiber layer 172 may optionally include basalt fiber cloth, wherein the weight of each cubic meter of basalt fiber cloth is greater than or equal to 100g and less than or equal to 700g.

[0063] In this embodiment, the weight of each cubic meter of basalt fiber cloth is greater than or equal to 100g and less than or equal to 700g, for example, 300g, 400g or 500g, which can ensure the high strength, high modulus, high temperature resistance and acid and alkali resistance of the backing plate 17.

[0064] In some embodiments, optionally, the fiber diameter of the basalt fiber layer 172 is greater than or equal to 9 μm and less than or equal to 16 μm.

[0065] In this embodiment, an excessively large fiber diameter in the basalt fiber layer 172 may reduce the strength and stiffness of the composite material because the smaller surface area of ​​the fibers reduces the bonding area with the resin, thus affecting the stress transfer effect between the fibers and the resin. Conversely, an excessively small fiber diameter may lead to poor dispersion in the resin matrix, thereby affecting the overall performance of the composite material. Therefore, a fiber diameter of 9 μm to 16 μm is preferred for the basalt fiber layer 172, for example, 10 μm, 12 μm, 14 μm, or 16 μm.

[0066] In some embodiments, the resin layer 174 may optionally include one or a combination of the following: a vinyl resin layer, a phenolic resin layer, an epoxy resin layer, and a polyester resin layer.

[0067] In this embodiment, different resins combined with basalt fibers can achieve different properties and effects, and the selection is based on actual requirements. Vinyl resin has good processing performance and room temperature curing performance, while also possessing the mechanical properties, toughness, and corrosion resistance of epoxy resin. Epoxy resin exhibits better shear and compressive strength due to its optimal compatibility with basalt fibers. Phenolic resin composite basalt fiber cloth has better thermal stability and abrasion resistance.

[0068] like Figure 3 As shown, a second aspect of the present invention provides a photovoltaic module 1, including a backsheet 17 as provided in any embodiment of the first aspect of the present invention. Since the photovoltaic module 1 provided by the present invention includes the backsheet 17 provided in any embodiment of the first aspect of the present invention, it possesses all the beneficial effects of the backsheet 17 provided in any embodiment of the first aspect of the present invention.

[0069] In some embodiments, optionally, such as Figure 3 As shown, the photovoltaic module 1 also includes a panel 11, a front panel 13, a cell 15, and a mounting plate 19: the front panel 13 is located on one side of the panel 11; the cell 15 is located on the side of the front panel 13 away from the panel 11; the back panel 17 is located on the side of the cell 15 away from the front panel 13; and the mounting plate 19 is located on the side of the back panel 17 away from the cell 15.

[0070] In this embodiment, the photovoltaic module 1, from top to bottom, includes a panel 11, a front panel 13, a cell 15, a back panel 17, and a mounting plate 19. The basalt fiber-resin composite back panel 17 of this invention provides excellent support for the cell 15, preventing damage to the cell 15 under external forces. It should be understood that in conventional photovoltaic module 1 structures, the cell 15 is easily damaged by prolonged high temperatures. This invention improves upon the back panel 17, providing heat insulation for the cell 15 and ensuring its safe operation.

[0071] In some embodiments, the panel 11 may optionally include one or a combination of the following: PVDF (Polyvinyl fluoride) sheet, PVF (Polyvinyl fluoride) sheet, and ETFE (ethylene tetrafluoroethylene) sheet.

[0072] In this embodiment, PVDF, PVF and ETFE all have good chemical corrosion resistance, high temperature resistance, oxidation resistance, weather resistance and radiation resistance, and are suitable for use as the panel 11 of photovoltaic module 1.

[0073] In some embodiments, the front panel 13 may optionally include one or a combination of the following: PET (Polyethylene Terephthalate) sheet and EPE (Expandable Polyethylene) sheet.

[0074] In this embodiment, PET possesses excellent physical and mechanical properties, chemical resistance, optical properties, and electrical properties, thus it can be used as the material for the front panel 13 of the photovoltaic module 1. PET has high light transmittance, effectively transmitting sunlight and improving the power generation efficiency of the photovoltaic module 1. Furthermore, PET has good weather resistance, allowing it to be used in harsh environmental conditions and extending the service life of the photovoltaic module 1. EPE has excellent cushioning, thermal insulation, and moisture-proof properties, therefore it can also be used as the material for the front panel 13 of the photovoltaic module 1. EPE can effectively protect the photovoltaic module 1 from impacts and vibrations, improving the reliability of the photovoltaic module 1. In addition, the thermal insulation properties of EPE can effectively reduce the temperature of the photovoltaic module 1, improving the power generation efficiency of the photovoltaic module 1.

[0075] In some embodiments, the battery 15 may optionally include one or a combination of the following: PERC (Passivated Emitter Rear Cell) battery, TOPcon (Top Emitting Contact) battery, and IBC (Interdigitated Back Contact) battery.

[0076] In this embodiment, PERC cells, TOPcon cells, and IBC cells all have long photoelectric conversion lifetimes and low power decay.

[0077] In some embodiments, the mounting plate 19 may optionally include one or a combination of the following: PVDF (Polyvinyl fluoride) plate, PVF (Polyvinyl formal) plate, and ETFE (Ethylene tetrafluoroethylene) plate.

[0078] In this embodiment, the PVDF board, PVF board and ETFE board all have excellent weather resistance, corrosion resistance and chemical stability, so they have a good protective effect during the installation of photovoltaic module 1. They can effectively prevent photovoltaic module 1 from being affected by environmental factors such as ultraviolet rays, rain and temperature changes, thereby improving the service life and performance of photovoltaic module 1.

[0079] In some embodiments, the photovoltaic module 1 may optionally include: a first adhesive layer 12 disposed between the panel 11 and the front panel 13; a second adhesive layer 14 disposed between the front panel 13 and the cell 15; a third adhesive layer 16 disposed between the cell 15 and the back panel 17; and a fourth adhesive layer 18 disposed between the back panel 17 and the mounting plate 19.

[0080] In this embodiment, by providing an adhesive layer between the panel 11, the front panel 13, the battery 15, the back panel 17 and the mounting plate 19, the overall stability of the photovoltaic module 1 can be improved.

[0081] In some embodiments, the first adhesive layer 12, the second adhesive layer 14, the third adhesive layer 16 and the fourth adhesive layer 18 may each include one or a combination of the following: an EVA (Ethylene vinyl acetate copolymer) layer, a POE (Poly olefin elastomer) layer and an EVA-POE composite layer.

[0082] In this embodiment, both the EVA layer and the POE layer have excellent connectivity, which improves the overall stability of the photovoltaic module 1.

[0083] like Figure 5 As shown, a third aspect of the present invention provides a method for preparing a backplate, comprising:

[0084] S502: Preparation of resin solution;

[0085] S504: A composite material is prepared by coating a resin solution onto one side of a basalt fiber.

[0086] S506: Multiple composite materials are stacked together, wherein the resin adhesive layer and the basalt fiber layer are alternately arranged;

[0087] S508: Multiple composite materials are laminated together to form a backing plate.

[0088] The backsheet preparation method provided by this invention, which alternates between basalt fiber layers and resin layers, offers superior thermal insulation and compressive strength compared to conventional methods that use a single layer of basalt fiber layer superimposed with a single layer of resin layer, while maintaining the same thickness. Specifically, the alternating backsheet structure limits vertical heat conduction and disrupts heat flow paths through the different thermal expansion coefficients of each layer, resulting in better thermal insulation. Furthermore, in applications involving high temperatures or extreme temperature variations, this design reduces the risk of thermal stress and structural damage. In addition, the alternating use of different materials increases the damping capacity of the backsheet, helping to reduce vibration and noise transmission, which is particularly important in applications requiring reduced noise and vibration.

[0089] In some embodiments, the basalt fiber may optionally include basalt fiber cloth, and the preparation method of the backing plate may further include: sequentially crushing, melting, drawing, and impregnating basalt ore with a sizing agent to obtain basalt fiber filaments; and weaving the basalt fiber filaments to obtain basalt fiber cloth.

[0090] In this embodiment, basalt ore can be sequentially crushed, melted, drawn into fibers, and impregnated with a sizing agent to obtain basalt fiber filaments; the basalt fiber filaments are then woven to obtain basalt fiber cloth. Basalt fiber cloth exhibits better compatibility with resin and demonstrates superior shear strength and compressive strength.

[0091] The following analysis of the backsheet of this invention is from another perspective. It's important to understand that current photovoltaic modules, due to prolonged exposure to outdoor sunlight, accumulate significant heat, causing deformation and increasing their flammability. Therefore, there is an urgent need to improve the strength and fire resistance of photovoltaic modules. Basalt fiber (BF) is a new type of high-quality reinforcing material for composite materials. It is highly favored in the field of fiber-reinforced composite materials due to its excellent mechanical properties, corrosion resistance, and heat resistance. The tensile strength and elastic modulus of basalt fiber are between those of glass fiber and carbon fiber, and it possesses the best heat resistance among the three. Compared to expensive carbon fiber, BF is a cost-effective choice. Compared to glass fiber, BF has better mechanical properties. The properties of basalt fiber, glass fiber, carbon fiber, and aramid fiber are shown in Table 1 below.

[0092]

[0093] Table 1

[0094] In addition, basalt fiber has the highest operating temperature range, such as Figure 4 As shown, the tensile strength of basalt fiber is higher than that of glass fiber within the operating temperature range.

[0095] Basalt fiber and glass fiber have similar mechanical properties. Current research shows that basalt fiber has good interfacial adhesion to the epoxy resin matrix. Compared with glass fiber / epoxy resin composites, basalt fiber / epoxy resin composites have superior mechanical properties and wear resistance, and the compatibility between basalt fiber and epoxy resin is better than that of glass fiber. Table 2 below compares the mechanical properties of BF / epoxy resin composites and GF / epoxy resin composites. As shown in Table 2, the tensile strength, tensile modulus, flexural strength, and flexural modulus of BF / epoxy resin composites are all superior to those of GF / epoxy resin composites. Furthermore, the shear strength indicates that the former has better interfacial compatibility with the epoxy resin than the latter.

[0096]

[0097] Table 2

[0098] Currently, basalt fiber is mostly used in photovoltaic frame brackets. Its market price is much lower than that of similar galvanized steel brackets and aluminum brackets. Its weight is only one-quarter of that of galvanized brackets and two-thirds of that of aluminum brackets, while its strength is four times that of ordinary steel.

[0099] Based on this, such as Figure 3 As shown, the present invention provides a photovoltaic module 1, which includes:

[0100] Panel 11: It is a fluoropolymer film material, which can be one of PVDF film, PVF film or ETFE film, with a thickness of 25-35μm, and has excellent waterproof and wear-resistant properties.

[0101] First adhesive layer 12: EVA, with a thickness of 0.3mm to 0.6mm;

[0102] Front panel 13: Made of transparent PET or EPE film material with a thickness of 0.25mm to 0.45mm;

[0103] Second adhesive layer 14: EVA or POE material or EVA and POE co-extruded film material, with a thickness of 0.3mm to 0.6mm;

[0104] Battery 15: Choose one of PERC, TOPcon, or IBC;

[0105] Third adhesive layer 16: EVA or POE material or EVA and POE co-extruded film material, with a thickness of 0.3mm to 0.6mm;

[0106] Backing plate 17: Made of basalt fiber composite material, obtained by impregnation, coating, and impregnation-pressing methods to combine basalt fiber cloth with resin, its structure is as follows. Figure 2 As shown, the fabric weight of basalt fiber is 100 g / m³. 3 Up to 700g / m 3 The fiber diameter ranges from 9μm to 16μm, and the warp and weft knitting density ranges from 3×3 to 15×15. The impregnating resin can be one of vinyl ester resin, epoxy resin, or phenolic resin, with basalt fiber comprising 5%-55%.

[0107] Fourth adhesive layer 18: EVA material is selected, with a thickness of 0.3mm to 0.6mm;

[0108] Mounting plate 19: Made of fluoropolymer film material, which can be one of PVDF film, PVF film or ETFE film, with a thickness of 25μm to 35μm.

[0109] The resins used can be vinyl ester resin, phenolic resin, epoxy resin, and polyester resin. Different resins combined with basalt fiber cloth can achieve different properties and effects, and the selection should be based on actual requirements. Vinyl ester resin has good processing performance and room temperature curing performance, while also possessing the mechanical properties, toughness, and corrosion resistance of epoxy resin. Epoxy resin exhibits better shear and compressive strength due to its optimal compatibility with basalt fiber. Phenolic resin composite basalt fiber cloth has better thermal stability and abrasion resistance.

[0110] Basalt fiber cloth is made from basalt ore through processes such as crushing, washing, melting, drawing, and impregnation with sizing agents. In photovoltaic modules, it typically serves as the matrix for basalt fiber composite materials with a basis weight of 100 g / m². 3 Up to 700g / m 3 The fiber diameter is between 9μm and 16μm, the warp and weft weave density is between 3×3 and 15×15, and the weave structure can be one of plain weave, twill weave, or satin weave.

[0111] like Figure 6 As shown, the preparation method of basalt fiber composite material includes the following steps:

[0112] S602: Mix the resin and solvent evenly to obtain a colloid;

[0113] S604: Coating the colloid onto basalt fiber cloth;

[0114] S606: Drying;

[0115] S608: Cutting;

[0116] S610: Overlap;

[0117] In this step, the resin-basalt fiber composite material is stacked together, with the basalt fiber layer and the resin layer alternating.

[0118] S612: Combination;

[0119] S614: Lamination;

[0120] S616: Cutting.

[0121] The photovoltaic modules prepared by this invention utilize basalt fiber composite materials, which possess excellent properties such as high strength, high modulus, high temperature resistance, and acid and alkali resistance. This makes them ideal reinforcing materials, effectively improving the strength of photovoltaic modules. The lightweight nature of basalt fiber reduces the weight of the photovoltaic modules and lowers costs. Basalt fiber composite materials also exhibit good corrosion resistance, allowing for long-term use in humid or acidic / alkaline environments without damage. Their low thermal conductivity and excellent heat insulation properties help protect solar panels from damage caused by prolonged high temperatures. Basalt is a renewable natural resource, and photovoltaic modules made from basalt fiber align with the principles of environmentally friendly and sustainable development.

[0122] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0123] Although embodiments of this application have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of this application, the scope of which is defined by the claims and their equivalents.

Claims

1. A backsheet characterized by, A back sheet for a photovoltaic module, the back sheet comprising: a basalt fiber layer; a resin layer, wherein the basalt fiber layer is at least two layers, and the resin layer is disposed between the two layers of the basalt fiber layer, or the resin layer is at least two layers, and the basalt fiber layer is disposed between the two layers of the resin layer; wherein the basalt fiber layer and the resin layer have different coefficients of thermal expansion, and the resin layer comprises one or a combination of the following: a vinyl resin layer, a phenolic resin layer, an epoxy resin layer, and a polyester resin layer; the mass percentage of the basalt fiber layer in the back sheet is greater than or equal to 5% and less than or equal to 55%; the mass percentage of the resin layer in the back sheet is greater than or equal to 45% and less than or equal to 95%; the fiber diameter of the basalt fiber layer is greater than or equal to 9 μm and less than or equal to 16 μm.

2. The back sheet of claim 1, wherein: the number of resin layers is greater than or equal to 2 and less than or equal to 3; the number of basalt fiber layers is greater than or equal to 2 and less than or equal to 3, and the basalt fiber layers and the resin layers are alternately arranged.

3. The back sheet of claim 2, wherein: the mass percentage of the basalt fiber layer in the back sheet is greater than or equal to 20% and less than or equal to 30%; the mass percentage of the resin layer in the back sheet is greater than or equal to 70% and less than or equal to 80%.

4. The back sheet of claim 1, wherein: the basalt fiber layer comprises a basalt fiber cloth.

5. A photovoltaic module, characterized by, comprising: the back sheet of any one of claims 1 to 4.

6. The photovoltaic module of claim 5, wherein, further comprising: a panel; a front plate disposed on one side of the panel; a cell disposed on a side of the front plate away from the panel, and the back sheet is disposed on a side of the cell away from the front plate; a mounting plate disposed on a side of the back sheet away from the cell.

7. The photovoltaic module of claim 6, wherein: the panel comprises one or a combination of the following: a PVDF plate, a PVF plate, and an ETFE plate; and / or the front plate comprises one or a combination of the following: a PET plate and an EPE plate; and / or the cell comprises one or a combination of the following: a PERC cell, a TOPcon cell, and an IBC cell; and / or the mounting plate comprises one or a combination of the following: a PVDF plate, a PVF plate, and an ETFE plate.

8. The photovoltaic module of claim 6, wherein, further comprising: a first adhesive layer disposed between the panel and the front plate; a second adhesive layer disposed between the front plate and the cell; a third adhesive layer disposed between the cell and the back sheet; a fourth adhesive layer disposed between the back sheet and the mounting plate.

9. The photovoltaic module of claim 8, wherein, The first adhesive layer, the second adhesive layer, the third adhesive layer, and the fourth adhesive layer each comprise one or a combination of the following: an EVA layer, a POE layer, and an EVA-POE composite layer.

10. A method of producing a backsheet as claimed in any one of claims 1 to 3, characterized in that comprising: preparing a resin glue solution; applying the resin glue solution to one side of a basalt fiber layer to obtain a composite material; stacking a plurality of the composite materials, wherein the resin layers are spaced apart from the basalt fiber layers; pressing the plurality of the composite materials by lamination to form the back sheet; The thermal expansion coefficient of the basalt fiber layer and the resin layer is different, and the resin layer comprises one or a combination of the following: a vinyl resin layer, a phenolic resin layer, an epoxy resin layer, and a polyester resin layer.

11. The method of producing a backsheet according to claim 10, wherein The basalt fiber layer comprises a basalt fiber cloth, and the preparation method of the backboard further comprises: The basalt ore is sequentially crushed, melted, drawn, and treated with an impregnating agent to obtain basalt fiber filaments; The basalt fiber filaments are woven to obtain the basalt fiber cloth.

Images