Photovoltaic backboard and photovoltaic module

Abstract

The invention relates to the technical field of photovoltaic, particularly provides a photovoltaic backboard and a photovoltaic module, and aims to solve the problems that an existing PVDF (Polyvinylidene Fluoride) photovoltaic backboard is poor in water resistance and easy to crack after being used for a long time. Therefore, the photovoltaic backboard provided by the invention is prepared from the following components in parts by weight: 20 to 70 parts of polyacrylate resin, 10 to 70 parts of PVDF (Polyvinylidene Fluoride), 1 to 5 parts of poly alpha-methyl styrene, 1 to 5 parts of ultraviolet absorbent, 1 to 5 parts of light stabilizer and 1 to 10 parts of flexibilizer. By adjusting the formula of the photovoltaic back plate, the water resistance and impact strength of the prepared photovoltaic back plate can be improved, the problem that a PVDF photovoltaic back plate is prone to yellowing and cracking after being used for a long time is effectively solved, the prepared photovoltaic back plate has good ultraviolet light resistance and weather resistance, the service life can be prolonged, and the photovoltaic back plate is suitable for popularization and application. The long-term stable use can be realized.

Description

Technical Field

[0001] The present application relates to the field of photovoltaic technology, and specifically provides a photovoltaic backplane and a photovoltaic module. Background Art

[0002] One of the issues encountered in photovoltaic modules is the degradation of their sealants and backsheets. The polymer backsheet is crucial for maintaining safe and reliable operation of photovoltaic modules, supporting the entire module and protecting the silicon-based cell cores. However, prolonged UV radiation triggers photochemical reactions that can cause cracks and powdering in the polymer backsheet, ultimately leading to the collapse of the photovoltaic module. Therefore, surface covering materials are needed to protect the internal materials of the photovoltaic module from UV radiation while maintaining high transmittance in the wavelength region of the generated light (380-1100nm).

[0003] As the most important weather-resistant protective film on the air surface of a transparent backsheet, transparent fluorine film plays a key role in its weather resistance. PVDF, with its outstanding chemical and weather resistance, is particularly suitable for use as a solar backsheet film material. PVDF films typically utilize a single-layer structure and are white in color. However, PVDF films still have some drawbacks. For example, during the production process, excessive addition of PMMA to improve mechanical properties and aging resistance can lead to unclear textures, creases, and other cosmetic defects. The film also easily absorbs water. Furthermore, prolonged UV exposure can cause yellowing and cracking of the PVDF film, negatively impacting its service life.

[0004] Accordingly, this field requires a new technical solution to solve the above technical problems. Summary of the Invention

[0005] The present application aims to solve the above technical problems, namely, to solve the problems of poor water resistance of existing PVDF photovoltaic backsheets and easy cracking after long-term use.

[0006] In a first aspect, the present application provides a photovoltaic backsheet, which comprises the following components in parts by weight: 20 to 70 parts of polyacrylate resin, 10 to 70 parts of PVDF, 1 to 5 parts of poly-α-methylstyrene, 1 to 5 parts of ultraviolet absorber, 1 to 5 parts of light stabilizer, and 1 to 10 parts of toughening agent.

[0007] In the preferred technical solution of the above-mentioned photovoltaic backsheet, the photovoltaic backsheet includes the following components in parts by weight: 20 to 55 parts of polyacrylate resin, 35 to 70 parts of PVDF, 1 to 2 parts of poly-α-methylstyrene, 1 to 3 parts of ultraviolet absorber, 1 to 3 parts of light stabilizer, and 1 to 5 parts of toughening agent.

[0008] In the preferred technical solution of the above photovoltaic backsheet, the photovoltaic backsheet comprises the following components in parts by weight: 35 parts of polyacrylate resin, 60 parts of PVDF, 1 part of poly-α-methylstyrene, 1 part of ultraviolet absorber, 1 part of light stabilizer, and 2 parts of toughening agent.

[0009] In the preferred technical solution of the above-mentioned photovoltaic backsheet, the ultraviolet absorber is prepared by the following steps: (1) dissolving dihydroxybenzophenone in a solvent to obtain a dihydroxybenzophenone solution; (2) adding triethylamine to the dihydroxybenzophenone solution, and then stirring in an ice-water bath under N2 protection for 10 minutes to obtain a mixed solution; (3) adding arylsulfonyl chloride dropwise to the mixed solution, returning the temperature to room temperature after the addition, and maintaining the reaction at room temperature for 2 hours to obtain a reaction product; (4) extracting the reaction product with ethyl acetate solution, drying with anhydrous magnesium sulfate, filtering, drying, and then separating by column chromatography to obtain the ultraviolet absorber.

[0010] In the preferred technical solution of the above-mentioned photovoltaic backsheet, in step (1), the solvent is anhydrous CH2Cl2; and / or, in step (1), the molar volume ratio of the dihydroxybenzophenone to the solvent is 1:(2-3), preferably the molar volume ratio of the dihydroxybenzophenone to the solvent is 1:2.

[0011] In the preferred technical solution of the above photovoltaic backsheet, in step (2), the molar ratio of the triethylamine to the dihydroxybenzophenone is triethylamine:dihydroxybenzophenone=(1-1.2):1, preferably the molar ratio of the triethylamine to the dihydroxybenzophenone is triethylamine:dihydroxybenzophenone=1.1:1.

[0012] In the preferred technical solution of the above photovoltaic backsheet, in step (3), the molar ratio of the arylsulfonyl chloride to the dihydroxybenzophenone is arylsulfonyl chloride: dihydroxybenzophenone = (1.5-2): 1, preferably the molar ratio of the arylsulfonyl chloride to the dihydroxybenzophenone is arylsulfonyl chloride: dihydroxybenzophenone = 1.8: 1.

[0013] In the preferred technical solution of the above photovoltaic backsheet, the thickness of the photovoltaic backsheet is 300-500 μm, and preferably the thickness of the photovoltaic backsheet is 310 μm.

[0014] In the preferred technical solution of the above photovoltaic backsheet, the photovoltaic backsheet is produced by a screw extrusion process, wherein the extrusion temperature is 165-240° C. and the screw speed is 200-500 rpm.

[0015] In the preferred technical solution of the above-mentioned photovoltaic backsheet, the polyacrylate resin includes one or more of polymethyl methacrylate, polyethyl methacrylate, polypropyl methacrylate, polybutyl methacrylate, polymethyl acrylate, polyethyl acrylate, polypropyl acrylate, polybutyl acrylate, methyl methacrylate and styrene copolymer; and / or the toughening agent is one or more of diisononyl phthalate, triphenyl phosphate and diisooctyl adipate; and / or the light stabilizer is one or more of light stabilizer 770, o-hydroxybenzophenone, benzotriazole, salicylate, triazine and substituted acrylonitrile.

[0016] In a second aspect, the present application provides a photovoltaic module, which includes the above-mentioned photovoltaic backsheet.

[0017] Compared with the prior art, the photovoltaic backsheet of the present application has the following beneficial effects:

[0018] 1. The photovoltaic backsheet of the present application comprises, by weight, 20 to 70 parts of polyacrylate resin, 10 to 70 parts of PVDF, 1 to 5 parts of poly-α-methylstyrene, 1 to 5 parts of ultraviolet absorber, 1 to 5 parts of light stabilizer, and 1 to 10 parts of toughening agent. By adjusting the formula of the photovoltaic backsheet, the water resistance and impact strength of the photovoltaic backsheet can be improved, and the problem of yellowing and cracking of the PVDF photovoltaic backsheet after long-term use is effectively solved, so that the photovoltaic backsheet has good ultraviolet light resistance and weather resistance, can extend the service life, and can be used stably for a long time.

[0019] 2. The ultraviolet absorber of the present application is a reaction product generated by the reaction of dihydroxybenzophenone solution with triethylamine and arylsulfonyl chloride. Compared with the ultraviolet absorbers used in the prior art, it has a better effect of absorbing ultraviolet rays, is low in cost, and is easy to prepare. DETAILED DESCRIPTION

[0020] The preferred embodiments of the present application are described below. Those skilled in the art should understand that these embodiments are only used to explain the technical principles of the present application and are not intended to limit the scope of protection of the present application.

[0021] In this application, the term "and / or" describes the relationship between associated objects, indicating that three possible relationships exist. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. A and B can be singular or plural. The character " / " generally indicates that the associated objects are in an "or" relationship.

[0022] In this application, "at least one" means one or more, and "more than one" means two or more. "At least one of the following" or similar expressions refers to any combination of these items, including any combination of single items or plural items. For example, "at least one of a, b, or c", or "at least one of a, b, and c" can all mean: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, and c can be single or multiple.

[0023] It should be understood that in the various embodiments of the present application, the size of the serial numbers of the above-mentioned processes does not mean the order of execution. Some or all of the steps can be executed in parallel or sequentially. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0024] The terms used in the embodiments of the present application are for the purpose of describing specific embodiments only and are not intended to limit the present application. The singular forms "a", "an", "the" and "the" used in the embodiments of the present application and the appended claims are also intended to include plural forms unless the context clearly indicates otherwise.

[0025] The weights of the relevant components mentioned in the examples of this application may not only refer to the specific content of each component, but also represent the weight ratio between the components. Therefore, as long as the content of the relevant components is proportionally enlarged or reduced according to the examples of this application, it is within the scope disclosed in the examples of this application. Specifically, the mass described in the examples of this application may be a mass unit known in the chemical industry, such as μg, mg, g, kg, etc.

[0026] Based on the problem pointed out in the background art that the existing PVDF photovoltaic backsheet is prone to yellowing and cracking after long-term use.

[0027] The photovoltaic backsheet of the present application includes, by weight, 20 to 70 parts of polyacrylate resin, 10 to 70 parts of PVDF, 1 to 5 parts of poly-α-methylstyrene, 1 to 5 parts of ultraviolet absorber, 1 to 5 parts of light stabilizer, and 1 to 10 parts of toughening agent. By adjusting the formula of the photovoltaic backsheet, the transparency, water resistance and impact strength of the photovoltaic backsheet can be improved, and the problem of yellowing and cracking of the PVDF photovoltaic backsheet after long-term use is effectively solved, so that the photovoltaic backsheet has good ultraviolet light resistance and weather resistance, can extend the service life, and can be used stably for a long time.

[0028] Specifically, the present application provides a photovoltaic backboard, which includes the following components in parts by weight: 20 to 70 parts of polyacrylate resin, 10 to 70 parts of PVDF, 1 to 5 parts of poly-α-methylstyrene, 1 to 5 parts of ultraviolet absorber, 1 to 5 parts of light stabilizer, and 1 to 10 parts of toughening agent.

[0029] Preferably, the photovoltaic backsheet of the present application comprises the following components in parts by weight: 20 to 55 parts of polyacrylate resin, 35 to 70 parts of PVDF, 1 to 2 parts of poly-α-methylstyrene, 1 to 3 parts of ultraviolet absorber, 1 to 2 parts of light stabilizer, and 1 to 5 parts of toughening agent.

[0030] In some preferred embodiments, the photovoltaic backsheet of the present application includes the following components in parts by weight: 20 to 35 parts of polyacrylate resin, 50 to 70 parts of PVDF, 1 to 2 parts of poly-α-methylstyrene, 1 to 3 parts of ultraviolet absorber, 1 to 2 parts of light stabilizer, and 1 to 5 parts of toughening agent.

[0031] In some preferred embodiments, the photovoltaic backsheet of the present application includes the following components in parts by weight: 35 parts of polyacrylate resin, 60 parts of PVDF, 1 part of poly-α-methylstyrene, 1 part of ultraviolet absorber, 1 part of light stabilizer, and 2 parts of toughening agent.

[0032] Preferably, the thickness of the photovoltaic backsheet is 300-500 μm.

[0033] Specifically, the thickness of the photovoltaic backsheet may be 300 μm, 305 μm, 310 μm, 320 μm, 330 μm, 340 μm, 350 μm, 380 μm, 400 μm, 420 μm, 450 μm, 480 μm, 500 μm or a value between any two of the above numerical ranges.

[0034] Further preferably, the thickness of the photovoltaic backsheet is 310 μm.

[0035] In practical applications, the most preferred thickness of the photovoltaic backsheet is 310 μm, which can have both high light transmittance and high weather resistance, and can better increase the service life of the photovoltaic module.

[0036] Preferably, the photovoltaic backsheet is produced by a screw extrusion process, wherein the extrusion temperature is 165-240° C. and the screw speed is 200-500 rpm.

[0037] Preferably, the polyacrylate resin includes one or more of polymethyl methacrylate, polyethyl methacrylate, polypropyl methacrylate, polybutyl methacrylate, polymethyl acrylate, polyethyl acrylate, polypropyl acrylate, polybutyl acrylate, and a copolymer of methyl methacrylate and styrene.

[0038] Preferably, the toughening agent is one or more of diisononyl phthalate, triphenyl phosphate and diisooctyl adipate.

[0039] Preferably, the light stabilizer is one or more of light stabilizer 770, o-hydroxybenzophenone, benzotriazole, salicylate, triazine, and substituted acrylonitrile.

[0040] Preferably, the ultraviolet absorber of the present application is prepared by the following steps:

[0041] S1: dissolving dihydroxybenzophenone in a solvent to obtain a dihydroxybenzophenone solution.

[0042] S2: triethylamine was added to the dihydroxybenzophenone solution, followed by stirring in an ice-water bath under N2 protection for 10 min to obtain a mixed solution.

[0043] S3: Add arylsulfonyl chloride dropwise to the mixed solution, return the temperature to room temperature after the addition, and keep the reaction at room temperature for 2 hours to obtain a reaction product.

[0044] S4: extracting the reaction product with ethyl acetate solution, drying with anhydrous magnesium sulfate, filtering, and drying, and then separating by column chromatography to obtain a UV absorber.

[0045] Preferably, in step S1, the solvent is anhydrous CH2Cl2.

[0046] Preferably, in step S1, the molar volume ratio of dihydroxybenzophenone to the solvent is 1:(2-3), that is, hydroxybenzophenone:solvent=1 mol:(2-3)L or hydroxybenzophenone:solvent=1 mmol:(2-3)mL.

[0047] Specifically, the molar volume ratio of dihydroxybenzophenone to the solvent can be 1:2, 1:2.1, 1:2.2, 1:2.3, 1:2.4, 1:2.5, 1:2.6, 1:2.7, 1:2.8, 1:2.9, 1:3 or a ratio between any two of the above ratio ranges.

[0048] Most preferably, in step S1, the molar volume ratio of dihydroxybenzophenone to the solvent is 1:2, that is, dihydroxybenzophenone:solvent=1.0 mmol:2 mL.

[0049] Preferably, in step S2, the molar ratio of triethylamine to dihydroxybenzophenone is (1-1.2):1.

[0050] Specifically, the molar ratio of triethylamine to dihydroxybenzophenone can be 1:1, 1.1:1, 1.2:1, or a ratio between any two of the above ratio ranges.

[0051] Most preferably, in step S2, the molar ratio of triethylamine to dihydroxybenzophenone is 1.1:1.

[0052] Preferably, in step S3, the molar ratio of arylsulfonyl chloride to dihydroxybenzophenone is (1.5-2):1.

[0053] Specifically, the molar ratio of arylsulfonyl chloride to dihydroxybenzophenone can be 1.5:1, 1.6:1, 1.7:1, 1.8:1, 1.9:1, 2:1, or a ratio between any two of the above ratio ranges.

[0054] Most preferably, in step S3, the molar ratio of arylsulfonyl chloride to dihydroxybenzophenone is 1.8:1.

[0055] The photovoltaic backsheet of the present application is described in detail below through several specific embodiments.

[0056] Example 1

[0057] The photovoltaic backsheet of this embodiment is produced by a screw extrusion process, wherein the extrusion temperature is 220° C., the screw speed is 500 rpm, and the thickness of the photovoltaic backsheet is 310 μm.

[0058] The formula of the photovoltaic backsheet of this embodiment is as follows: 35 parts of polyacrylate resin (polymethyl methacrylate), 60 parts of PVDF, 1 part of poly-α-methylstyrene, 1 part of UV absorber, 1 part of light stabilizer (o-hydroxybenzophenone), and 2 parts of toughening agent (diisononyl phthalate).

[0059] The ultraviolet absorber of this embodiment is prepared by the following steps:

[0060] S1: In a 50 ml double-necked round-bottom flask, dissolve 1 mmol of dihydroxybenzophenone in 2 ml of anhydrous CH2Cl2 to obtain a dihydroxybenzophenone solution.

[0061] S2: 1.1 mmol of triethylamine was added to the dihydroxybenzophenone solution of step S1, and then stirred in an ice-water bath under N2 protection for 10 min to obtain a mixed solution.

[0062] S3: 1.8 mmol of arylsulfonyl chloride was added dropwise to the mixed solution of step S2, and the temperature was restored to room temperature after the addition, and the reaction was maintained at room temperature for 2 hours to obtain a reaction product.

[0063] S4: extracting the reaction product of step S3 with ethyl acetate solution, drying with anhydrous magnesium sulfate, filtering, and drying, and then separating by column chromatography to obtain a UV absorber.

[0064] Example 2

[0065] The formulation and preparation process of the photovoltaic backsheet of this embodiment are the same as those of Example 1, and the only difference from Example 1 is that the amounts of the components are different.

[0066] Specifically, the formula of the photovoltaic backsheet of this embodiment is as follows: 20 parts of polyacrylate resin (polymethyl methacrylate), 70 parts of PVDF, 1 part of poly-α-methylstyrene, 1 part of UV absorber, 1 part of light stabilizer (o-hydroxybenzophenone), and 7 parts of toughening agent (diisononyl phthalate).

[0067] In addition, the ultraviolet absorber in this embodiment is the ultraviolet absorber in Example 1.

[0068] Example 3

[0069] The formulation and preparation process of the photovoltaic backsheet of this embodiment are the same as those of Example 1, and the only difference from Example 1 is that the amounts of the components are different.

[0070] Specifically, the formula of the photovoltaic backsheet of this embodiment is as follows: 70 parts of polyacrylate resin (polymethyl methacrylate), 20 parts of PVDF, 1 part of poly-α-methylstyrene, 2 parts of UV absorber, 2 parts of light stabilizer (o-hydroxybenzophenone), and 5 parts of toughening agent (diisononyl phthalate).

[0071] In addition, the ultraviolet absorber in this embodiment is the ultraviolet absorber in Example 1.

[0072] Example 4

[0073] The formulation and preparation process of the photovoltaic backsheet of this embodiment are the same as those of Example 1, and the only difference from Example 1 is that the amounts of the components are different.

[0074] Specifically, the formula of the photovoltaic backsheet of this embodiment is as follows: 50 parts of polyacrylate resin (polymethyl methacrylate), 37 parts of PVDF, 2 parts of poly-α-methylstyrene, 3 parts of UV absorber, 3 parts of light stabilizer (o-hydroxybenzophenone), and 5 parts of toughening agent (diisononyl phthalate).

[0075] In addition, the ultraviolet absorber in this embodiment is the ultraviolet absorber in Example 1.

[0076] Example 5

[0077] The formulation and preparation process of the photovoltaic backsheet of this embodiment are the same as those of Example 1, and the only difference from Example 1 is that the amounts of the components are different.

[0078] Specifically, the formula of the photovoltaic backsheet of this embodiment is as follows: 55 parts of polyacrylate resin (polymethyl methacrylate), 35 parts of PVDF, 1 part of poly-α-methylstyrene, 2 parts of UV absorber, 2 parts of light stabilizer (o-hydroxybenzophenone), and 5 parts of toughening agent (diisononyl phthalate).

[0079] In addition, the ultraviolet absorber in this embodiment is the ultraviolet absorber in Example 1.

[0080] Example 6

[0081] The formulation and preparation process of the photovoltaic backsheet of this embodiment are the same as those of Example 1, and the only difference from Example 1 is that the components of the formulation are different.

[0082] Specifically, the formula of the photovoltaic backsheet of this embodiment is as follows: 35 parts of polyacrylate resin (polymethyl acrylate), 60 parts of PVDF, 1 part of poly-α-methylstyrene, 1 part of UV absorber, 1 part of light stabilizer (benzotriazole), and 2 parts of toughening agent (diisooctyl adipate).

[0083] In addition, the ultraviolet absorber in this embodiment is the ultraviolet absorber in Example 1.

[0084] Example 7

[0085] The formulation and preparation process of the photovoltaic backsheet of this embodiment are the same as those of Example 1, and the only difference from Example 1 is that the components of the formulation are different.

[0086] Specifically, the formula of the photovoltaic backsheet of this embodiment is as follows: 35 parts of polyacrylate resin (polymethyl acrylate), 60 parts of PVDF, 1 part of poly-α-methylstyrene, 1 part of ultraviolet absorber, 1 part of light stabilizer (light stabilizer 770), and 2 parts of toughening agent (triphenyl phosphate).

[0087] In addition, the ultraviolet absorber in this embodiment is the ultraviolet absorber in Example 1.

[0088] Example 8

[0089] The formulation and preparation process of the photovoltaic backsheet of this embodiment are the same as those of Example 1, and the only difference from Example 1 is that the preparation process of the ultraviolet absorber is different.

[0090] Specifically, the ultraviolet absorber of this embodiment is prepared by the following steps:

[0091] S1: In a 50 ml double-necked round-bottom flask, dissolve 1 mmol of dihydroxybenzophenone in 3 ml of anhydrous CH2Cl2 to obtain a dihydroxybenzophenone solution.

[0092] S2: 1.2 mmol of triethylamine was added to the dihydroxybenzophenone solution of step S1, and then stirred in an ice-water bath under N2 protection for 10 min to obtain a mixed solution.

[0093] S3: 2 mmol of arylsulfonyl chloride was added dropwise to the mixed solution of step S2, and the temperature was restored to room temperature after the addition, and the reaction was maintained at room temperature for 2 hours to obtain a reaction product.

[0094] S4: extracting the reaction product of step S3 with ethyl acetate solution, drying with anhydrous magnesium sulfate, filtering, and drying, and then separating by column chromatography to obtain a UV absorber.

[0095] Example 9

[0096] The formulation and preparation process of the photovoltaic backsheet of this embodiment are the same as those of Example 1, and the only difference from Example 1 is that the preparation process of the ultraviolet absorber is different.

[0097] Specifically, the ultraviolet absorber of this embodiment is prepared by the following steps:

[0098] S1: In a 50 ml double-necked round-bottom flask, dissolve 1 mmol of dihydroxybenzophenone in 3 ml of anhydrous CH2Cl2 to obtain a dihydroxybenzophenone solution.

[0099] S2: 1 mmol of triethylamine was added to the dihydroxybenzophenone solution in step S1, and then stirred in an ice-water bath under N2 protection for 10 min to obtain a mixed solution.

[0100] S3: 1.5 mmol of arylsulfonyl chloride was added dropwise to the mixed solution of step S2, and the temperature was restored to room temperature after the addition, and the reaction was maintained at room temperature for 2 hours to obtain a reaction product.

[0101] S4: extracting the reaction product of step S3 with ethyl acetate solution, drying with anhydrous magnesium sulfate, filtering, and drying, and then separating by column chromatography to obtain a UV absorber.

[0102] Comparative Example 1

[0103] The photovoltaic backsheet of this comparative example comprises a 200 μm PVDF film and a 100 μm PET film, which are bonded to each other. The PVDF film is produced by a screw extrusion process at an extrusion temperature of 230° C., a screw speed of 200 rpm, and a thickness of 200 μm.

[0104] The formula of the PVDF film of this comparative example is as follows: 20 parts of polymethyl methacrylate and 80 parts of PVDF.

[0105] Comparative Example 2

[0106] The formula and preparation process of the photovoltaic backsheet of this comparative example are the same as those of Example 1. The only difference from Example 1 is that the ultraviolet light absorber is different. The ultraviolet light absorber of this comparative example is UV326.

[0107] Test example

[0108] The photovoltaic backsheets obtained in the above examples and comparative examples were tested to test the light transmittance, UV transmittance, elongation at break and water vapor transmittance of the photovoltaic backsheets. The test results are shown in Table 1.

[0109] Among them, the light transmittance is tested in accordance with GB / T 2410-2008; the elongation at break is tested in accordance with GB / T13542.2-2021; the water vapor transmission rate is tested in accordance with IEC 62788-2, and the test conditions are temperature 85°C and relative humidity 85%; the UV transmittance is tested by UV-visible spectrophotometry using a UV-visible spectrophotometer, and the specimens are the same as those in GB / T 2410-2008.

[0110] Table 1 Test results of photovoltaic backsheets of embodiment and comparative example

[0111] From the test data in Table 1, we can see that:

[0112] 1. Comparing Example 1 with Comparative Examples 1 and 2, the water vapor permeability of Example 1 is lower than those of Comparative Examples 1 and 2, the light transmittance of Example 1 is the same as those of Comparative Examples 1 and 2, the elongation at break of Example 1 is greater than that of Comparative Examples 1 and 2, and the ultraviolet transmittance of Example 1 is much lower than that of Comparative Examples 1 and 2. It can be seen that the water resistance and impact strength of the photovoltaic backsheet of the present application are significantly improved. In addition, the photovoltaic backsheet of the present application has good ultraviolet light resistance and weather resistance, and can effectively extend the service life.

[0113] 2. Comparing Examples 1 to 7, the water vapor permeability of Examples 3, 4, and 5 is much greater than that of Example 1, and the elongation at break of Examples 3, 4, and 5 is much lower than that of Example 1. It can be seen that reducing the amount of PVDF will reduce the elongation at break, thereby affecting the impact resistance and weather resistance of the photovoltaic backsheet, while increasing the amount of polyacrylate resin will increase the water vapor permeability, thereby affecting the water barrier properties of the photovoltaic backsheet. Therefore, in practical applications, it is necessary to control the amount of PVDF and polyacrylate resin. Preferably, the weight proportion of polyacrylate resin is 20-55 parts, and the weight proportion of PVDF is 35-70 parts; further preferably, the weight proportion of polyacrylate resin is 20-30 parts, and the weight proportion of PVDF is 50-70 parts; most preferably, the weight proportion of polyacrylate resin is 35 parts, and the weight proportion of PVDF is 60 parts, which can effectively improve the water barrier properties, impact resistance, and weather resistance.

[0114] Thus far, the technical solutions of the present application have been described in conjunction with preferred embodiments. However, it is readily understood by those skilled in the art that the scope of protection of the present application is clearly not limited to these specific embodiments. Without departing from the principles of the present application, those skilled in the art may make equivalent changes or substitutions to the relevant technical features, and the technical solutions after such changes or substitutions will fall within the scope of protection of the present application.

Claims

1. A photovoltaic backsheet, characterized in that: The photovoltaic backsheet comprises the following components in parts by weight: 20 to 70 parts of polyacrylate resin, 10 to 70 parts of PVDF, 1 to 5 parts of poly-α-methylstyrene, 1 to 5 parts of ultraviolet absorber, 1 to 5 parts of light stabilizer, and 1 to 10 parts of toughening agent.

2. The photovoltaic backsheet according to claim 1, characterized in that: The photovoltaic backsheet comprises the following components in parts by weight: 20 to 55 parts of polyacrylate resin, 35 to 70 parts of PVDF, 1 to 2 parts of poly-α-methylstyrene, 1 to 3 parts of ultraviolet absorber, 1 to 3 parts of light stabilizer, and 1 to 5 parts of toughening agent.

3. The photovoltaic backsheet according to claim 1, characterized in that: The photovoltaic backsheet comprises the following components in parts by weight: 35 parts of polyacrylate resin, 60 parts of PVDF, 1 part of poly-α-methylstyrene, 1 part of UV absorber, 1 part of light stabilizer, and 2 parts of toughening agent.

4. The photovoltaic backsheet according to claim 1, characterized in that: The ultraviolet absorber is prepared by the following steps: (1) dissolving dihydroxybenzophenone in a solvent to obtain a dihydroxybenzophenone solution; (2) adding triethylamine to the dihydroxybenzophenone solution, and then stirring in an ice-water bath under N2 protection for 10 minutes to obtain a mixed solution; (3) adding arylsulfonyl chloride dropwise to the mixed solution, returning the temperature to room temperature after the addition, and maintaining the reaction at room temperature for 2 hours to obtain a reaction product; (4) The reaction product is extracted with ethyl acetate solution, dried with anhydrous magnesium sulfate, filtered, and dried, and then separated by column chromatography to obtain a UV absorber.

5. The photovoltaic backsheet according to claim 4, characterized in that: In step (1), the solvent is anhydrous CH2Cl2; And / or, in step (1), the molar volume ratio of the dihydroxybenzophenone to the solvent is 1:(2-3), preferably the molar volume ratio of the dihydroxybenzophenone to the solvent is 1:

2.

6. The photovoltaic backsheet according to claim 4, characterized in that: In step (2), the molar ratio of the triethylamine to the dihydroxybenzophenone is triethylamine:dihydroxybenzophenone=(1-1.2):1, preferably the molar ratio of the triethylamine to the dihydroxybenzophenone is triethylamine:dihydroxybenzophenone=1.1:

1.

7. The photovoltaic backsheet according to claim 4, characterized in that: In step (3), the molar ratio of the arylsulfonyl chloride to the dihydroxybenzophenone is arylsulfonyl chloride: dihydroxybenzophenone = (1.5-2): 1, preferably the molar ratio of the arylsulfonyl chloride to the dihydroxybenzophenone is arylsulfonyl chloride: dihydroxybenzophenone = 1.8:

1.

8. The photovoltaic backsheet according to claim 1, characterized in that: The thickness of the photovoltaic backsheet is 300 to 500 μm, preferably 310 μm. And / or, the photovoltaic backsheet is produced by a screw extrusion process, wherein the extrusion temperature is 165-240° C. and the screw speed is 200-500 rpm.

9. The photovoltaic backsheet according to any one of claims 1 to 8, characterized in that: The polyacrylate resin includes one or more of polymethyl methacrylate, polyethyl methacrylate, polypropyl methacrylate, polybutyl methacrylate, polymethyl acrylate, polyethyl acrylate, polypropyl acrylate, polybutyl acrylate, methyl methacrylate and styrene copolymer; And / or, the toughening agent is one or more of diisononyl phthalate, triphenyl phosphate, and diisooctyl adipate; And / or, the light stabilizer is one or more of light stabilizer 770, o-hydroxybenzophenone, benzotriazole, salicylate, triazine, and substituted acrylonitrile.

10. A photovoltaic module, characterized in that: A photovoltaic backsheet comprising the photovoltaic backsheet according to any one of claims 1 to 9.

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