Photovoltaic module backsheet, method of making the same, and photovoltaic module

Abstract

The application discloses a photovoltaic module backboard and a preparation method thereof and a photovoltaic module, and belongs to the technical field of photovoltaic power generation. The photovoltaic module backboard comprises a backboard body; the backboard body has a first surface and a second surface opposite to each other; the first surface is attached with a first fluorine coating, and the surface of the first fluorine coating away from the backboard body is attached with a flame-retardant layer; the flame-retardant layer contains carbon black, and the content of the carbon black in the flame-retardant layer is 0.2wt%-2wt%. The application sets the flame-retardant layer on the surface of the backboard, so that the flame-retardant property reaches VTM-0 of UL94; and a specific amount of carbon black material is added in the flame-retardant layer, so that the aging resistance of the backboard is obviously improved, and the photovoltaic backboard has good aging resistance and flame-retardant effect simultaneously.

Description

Technical Field

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

[0002] Currently, with the expansion of photovoltaic power plants (especially distributed rooftop projects), fire protection needs are increasing, and stringent safety standards require modules to pass flame-retardant tests. The continuous rise in global photovoltaic installations, particularly in residential and commercial rooftop projects, directly increases the demand for flame-retardant backsheets. The requirements for module lifespan and reliability in large power plants make weather-resistant flame-retardant backsheets the preferred choice. Therefore, we need to develop a backsheet product with excellent aging resistance, high reflectivity, and superior flame-retardant properties. Existing technologies have published numerous studies on flame-retardant backsheets, primarily focusing on the environmental friendliness, barrier properties, and mechanical properties of the flame retardants used, without emphasizing the aging resistance of the backsheets. Therefore, their use in photovoltaic modules may present certain problems.

[0003] Existing technologies disclose a multi-layered solar backsheet containing only halogen-free flame retardants, with each layer exhibiting flame retardancy. This backsheet comprises a weather-resistant layer, a base film layer (containing flame retardants), and an encapsulation functional layer. Existing technologies also disclose a coating material for solar cell backsheets and its preparation method, enabling the solar cell backsheet to possess good flame retardant properties and overall performance. Furthermore, existing technologies disclose a method that uses co-extrusion technology to strongly bond the adhesive layer and structural layer, avoiding the cracking issues that occur with traditional backsheet layers bonded with adhesive when heated, while also providing good flame retardant effects and thermal conductivity. However, the above technologies primarily improve the flame retardant properties of the backsheet and do not guarantee good aging resistance. Summary of the Invention

[0004] The main objective of this application is to provide a photovoltaic module backsheet, its preparation method, and a photovoltaic module, in order to solve the problem that the backsheet of the photovoltaic module in the prior art cannot simultaneously achieve good flame retardancy and aging resistance.

[0005] To achieve the above objectives, according to one aspect of this application, a photovoltaic module backsheet is provided, including a backsheet body; the backsheet body has opposing first and second surfaces; a first fluorine coating is attached to the first surface, and a flame-retardant layer is attached to the surface of the first fluorine coating away from the backsheet body; wherein the flame-retardant layer contains carbon black, and the content of carbon black in the flame-retardant layer is 0.2wt% to 2wt%.

[0006] Furthermore, the thickness of the backplate body is 250~280μm.

[0007] Furthermore, the thickness of the first fluorine coating is 5~10μm.

[0008] Furthermore, the thickness of the flame-retardant layer is 20~30μm.

[0009] Furthermore, the particle size D90 of the carbon black is 300~500nm.

[0010] Furthermore, the carbon black content in the flame retardant layer is 0.4wt%~0.8wt%.

[0011] Furthermore, the material of the first fluorine coating is polyvinylidene fluoride and / or polytetrafluoroethylene.

[0012] Furthermore, a second fluorine coating is attached to the second surface.

[0013] Furthermore, the thickness of the second fluorine coating is 5~10μm.

[0014] Furthermore, the material of the second fluorine coating is polyvinylidene fluoride and / or polytetrafluoroethylene.

[0015] Furthermore, an anti-black layer is attached to the surface of the second fluorine coating away from the back panel body.

[0016] Furthermore, the thickness of the anti-black layer is 15~30μm.

[0017] Furthermore, the anti-black layer contains red, yellow, and blue pigments.

[0018] Furthermore, the weight ratio of red pigment, yellow pigment and blue pigment is (1~2):(3~3.5):(1~1.5).

[0019] Furthermore, red pigment comes from red masterbatch, yellow pigment comes from yellow masterbatch, and blue pigment comes from blue masterbatch.

[0020] Furthermore, the particle sizes of the red masterbatch, yellow masterbatch, and blue masterbatch are 100~500nm, respectively.

[0021] Furthermore, the matrix resins of the red masterbatch, the yellow masterbatch, and the blue masterbatch are all acrylic resins.

[0022] Furthermore, the red pigment in the red masterbatch is 10wt% to 30wt% of the matrix resin of the red masterbatch.

[0023] Furthermore, the yellow pigment in the yellow masterbatch is 10wt% to 30wt% of the matrix resin of the yellow masterbatch.

[0024] Furthermore, the blue pigment in the blue masterbatch is 10wt% to 30wt% of the matrix resin of the blue masterbatch.

[0025] According to a second aspect of this application, a method for preparing the aforementioned photovoltaic module backsheet is provided, comprising:

[0026] Step S1: Apply the first fluorine material to the first surface of the backplate body, and form the first fluorine coating after the first curing.

[0027] Step S2: The flame retardant slurry is applied to the surface of the first fluorine coating away from the backsheet body, and after the second curing, a flame retardant layer is formed, thereby obtaining the photovoltaic module backsheet; wherein, the flame retardant slurry contains carbon black, and the content of carbon black in the flame retardant layer is 0.2wt%~2wt%.

[0028] Furthermore, the second curing temperature is 130~150℃, and the second curing time is 3~5 minutes.

[0029] Furthermore, the flame-retardant paste comprises the following components by weight: 120-125 parts of base resin, 55-110 parts of flame retardant, 5-10 parts of first curing agent, 190-210 parts of first diluent, 1-2 parts of first matting agent, 2-3 parts of additives, and 2-3 parts of carbon black.

[0030] Furthermore, the first fluorinated material is polyvinylidene fluoride and / or polytetrafluoroethylene.

[0031] Furthermore, the thickness of the first fluorine coating is 5~10μm.

[0032] Furthermore, the thickness of the backplate body is 250~280μm.

[0033] Furthermore, the thickness of the flame-retardant layer is 20~30μm.

[0034] Furthermore, the matrix resin is selected from at least one of acrylic resin, epoxy resin, phenolic resin, polyurethane, silicone resin, and polyolefin resin.

[0035] Further, the flame retardant is selected from at least one of brominated flame retardants, phosphorus-based flame retardants, and nitrogen-based flame retardants; further, the brominated flame retardant is selected from at least one of decabromodiphenyl ether, hexabromocyclododecane, and tetrabromobisphenol A; further, the phosphorus-based flame retardant is selected from at least one of phosphate esters, ammonium polyphosphate, and phosphonate esters; further, the nitrogen-based flame retardant is selected from at least one of melamine, melamine cyanurate, and dicyandiamide.

[0036] Further, the first curing agent is selected from at least one of ethylenediamine, diethylenetriamine, polyamide, Mannich base, cyclic aliphatic amine, phthalic anhydride, tetrahydrophthalic anhydride, hexamethylene diisocyanate trimer, isophorone diisocyanate trimer, methyl ethyl ketone peroxide, benzoyl peroxide, γ-aminopropyltriethoxysilane, and γ-(2,3-epoxypropoxy)propyltrimethoxysilane.

[0037] Further, the first diluent is selected from at least one of glycidyl acrylate, butyl glycidyl ether, neopentyl glycol diglycidyl ether, trimethylolpropane triglycidyl ether, ethyl acetate, propylene glycol methyl ether acetate, acetone, butanone, toluene, xylene, isopropanol, butyl acetate, cyclohexanone, 1,4-butanediol, and propylene carbonate.

[0038] Furthermore, the first matting agent is selected from at least one of fumed silica, polyethylene wax, polypropylene wax, oxidized polyethylene wax, micronized wax, polymethylurea resin, polyamide wax, kaolin, diatomaceous earth, and talc.

[0039] Furthermore, the additive is selected from at least one of leveling agents, defoamers, and ultraviolet absorbers.

[0040] Furthermore, step S2 is followed by step S3: applying the second fluorine material to the second surface of the backplate body opposite to the first surface, and forming the second fluorine coating after a third curing process.

[0041] Furthermore, step S3 is followed by step S4: applying the anti-black paste to the surface of the second fluorine coating away from the back panel body, and forming an anti-black layer after a fourth curing process.

[0042] Furthermore, the fourth curing temperature is 140~150℃, and the fourth curing time is 5~7 minutes.

[0043] Furthermore, the thickness of the second fluorine coating is 5~10μm.

[0044] Furthermore, the thickness of the anti-black layer is 15~30μm.

[0045] Furthermore, the second fluorinated material is polyvinylidene fluoride and / or polytetrafluoroethylene.

[0046] Furthermore, the anti-blackening paste contains red, yellow, and blue pigments.

[0047] Furthermore, the weight ratio of red pigment, yellow pigment and blue pigment is (1~2):(3~3.5):(1~1.5).

[0048] Furthermore, red pigment comes from red masterbatch, yellow pigment comes from yellow masterbatch, and blue pigment comes from blue masterbatch.

[0049] Furthermore, the anti-blackening paste includes the following components: by weight, 18-36 parts of red masterbatch, 54-63 parts of yellow masterbatch, 18-27 parts of blue masterbatch, 1-2 parts of second matting agent, 10-12 parts of second curing agent, and 12-16 parts of second diluent.

[0050] Furthermore, the red pigment is 10wt% to 30wt% of the matrix resin of the red masterbatch.

[0051] Furthermore, the yellow pigment is 10wt% to 30wt% of the matrix resin of the yellow masterbatch.

[0052] Furthermore, the blue pigment is 10wt% to 30wt% of the matrix resin of the blue masterbatch.

[0053] Furthermore, the matrix resins of the red masterbatch, the yellow masterbatch, and the blue masterbatch are all acrylic resins.

[0054] Furthermore, the second matting agent is selected from at least one of fumed silica, polyethylene wax, polypropylene wax, oxidized polyethylene wax, micronized wax, polymethylurea resin, polyamide wax, kaolin, diatomaceous earth, and talc.

[0055] Furthermore, the second curing agent is selected from at least one of ethylenediamine, diethylenetriamine, low molecular weight polyamide, Mannich base, cyclic aliphatic amine, phthalic anhydride, tetrahydrophthalic anhydride, hexamethylene diisocyanate trimer, isophorone diisocyanate trimer, methyl ethyl ketone peroxide, benzoyl peroxide, γ-aminopropyltriethoxysilane and γ-(2,3-epoxypropoxy)propyltrimethoxysilane, isocyanate, and epoxy-modified curing agents.

[0056] Further, the second diluent is selected from at least one of glycidyl acrylate, butyl glycidyl ether, neopentyl glycol diglycidyl ether, trimethylolpropane triglycidyl ether, ethyl acetate, propylene glycol methyl ether acetate, acetone, butanone, toluene, xylene, isopropanol, butyl acetate, cyclohexanone, 1,4-butanediol, and propylene carbonate.

[0057] According to a third aspect of this application, a photovoltaic module is provided, comprising a front glass panel, an upper encapsulating film, solar cells, a lower encapsulating film, and a rear backsheet; the rear backsheet is the photovoltaic module backsheet described above or a photovoltaic module backsheet obtained by the preparation method of the photovoltaic module backsheet described above.

[0058] Compared with the prior art, this application has the following beneficial effects:

[0059] This application provides a photovoltaic module backsheet, which achieves UL94 VTM-0 flame retardant performance by setting a flame retardant layer on the backsheet surface; and by adding a specific amount of carbon black material to the flame retardant layer, significantly improving the aging resistance of the backsheet, so that the backsheet has both good aging resistance and flame retardant effect. Attached Figure Description

[0060] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments and descriptions of this application are used to explain this application and do not constitute an undue limitation of this application. In the drawings:

[0061] Figure 1 These are schematic diagrams of the backsheets of the photovoltaic modules prepared in Examples 1-16 of this application;

[0062] Figure 2 This is a schematic diagram of the structure of the photovoltaic module backsheet prepared in Embodiment 17 of this application;

[0063] Figure 3 This is a schematic diagram of the structure of the backsheet of the photovoltaic module prepared in Comparative Example 4 of this application.

[0064] Figure label:

[0065] 1. Back panel body; 11. First fluorine coating; 12. Second fluorine coating; 2. Flame retardant layer; 3. Anti-black layer. Detailed Implementation

[0066] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present application will now be described in detail with reference to the embodiments.

[0067] As mentioned in the background technology, existing technologies mainly study the flame retardant effect of the flame retardant layer of the photovoltaic module backsheet, with less research on the weather resistance of the backsheet. In particular, it is necessary to ensure that the backsheet has good flame retardancy while also having excellent weather resistance, which directly affects the service life and performance of the backsheet.

[0068] According to one aspect of this application, a photovoltaic module backsheet is provided, such as... Figure 1 and Figure 2 As shown, it includes a back panel body 1, which has a first surface and a second surface opposite to each other; a first fluorine coating 11 is attached to the first surface, and a flame retardant layer 2 is attached to the surface of the first fluorine coating 11 away from the back panel body 1; wherein the flame retardant layer 2 contains carbon black, and the content of carbon black in the flame retardant layer 2 is 0.2wt%~2wt%.

[0069] This application adds a specific amount of carbon black material (0.2% to 2 wt%) to the flame-retardant layer, which ensures that the back panel has both good flame retardancy and aging resistance. The carbon black content can be any value or a range between any two of the following: 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1.0%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, 1.8%, 1.9%, and 2.0%. By setting a flame-retardant layer on the surface of the backsheet, its flame-retardant performance reaches UL94 VTM-0. Carbon black can strongly absorb ultraviolet light, which is the main cause of material aging and yellowing. By adding carbon black to the flame-retardant layer, ultraviolet light penetration into other layers inside the backsheet can be reduced, protecting the substrate from ultraviolet damage and thus extending the service life of the backsheet. Carbon black also has certain antioxidant properties, which can prevent the backsheet material from oxidizing under light and high temperature, further preventing yellowing and aging. This greatly improves the yellowing of the backsheet after long-term aging and also meets the color requirements (such as black) of the backsheet as a photovoltaic encapsulation material, making it better suited for the photovoltaic field.

[0070] To further improve the flame retardant effect, the thickness of the flame retardant layer 2 is controlled between 20 and 30 μm, for example, any value among 20 μm, 22 μm, 25 μm, 28 μm, and 30 μm, or any value between two of these ranges. Controlling the thickness within the above range ensures good flame retardant and anti-aging effects.

[0071] To improve the adhesion of the flame-retardant layer 2 to the backsheet and enhance its resistance to yellowing, in some embodiments, the first fluorine coating 11 is polyvinylidene fluoride and / or polytetrafluoroethylene; the thickness of the first fluorine coating 11 is 5~10μm, for example, any one or any value between 5, 6, 7, 8, 9, and 10μm; the thickness of the backsheet body 1 is controlled between 250~280μm, for example, any value between 250, 260, 270, and 280μm; the backsheet body can be selected from PET, PP, and PE backsheets, with PET backsheets being preferred. When both surfaces of the PET are coated with a fluorine coating, it serves as a CPC backsheet. By coating the backsheet surface with a fluorine layer, effective adhesion between the flame-retardant layer and the backsheet can be ensured, and the fluorine coating has excellent weather resistance, effectively resisting ultraviolet radiation, temperature and humidity changes, etc., extending the service life of the backsheet, and ensuring that the photovoltaic module can maintain good performance and reliability under long-term outdoor conditions.

[0072] To further improve the flame retardancy and anti-aging properties of the backsheet, the carbon black content and particle size were optimized. In some specific embodiments, the carbon black content in the flame retardant layer 2 is 0.4%~0.8wt%. To improve the dispersion effect, the selected carbon black particle size D90 is 300~500nm, for example, D90 is any value among 300, 350, 400, 450, and 500nm or any value between two of them. Controlling the amount of carbon black added within the above range can maintain the flame retardant performance while maximizing the aging resistance of carbon black, especially in resisting yellowing caused by ultraviolet rays, making the backsheet more stable and reliable in long-term performance under complex environments, meeting the requirements of photovoltaic backsheets for long-term outdoor use. By controlling the particle size within the above range, it helps to achieve uniform dispersion in the flame retardant layer, which is more conducive to the absorption and shielding of ultraviolet rays.

[0073] To firmly adhere the anti-black layer 3 to the second surface of the back panel and improve its aging resistance, in some specific embodiments, a second fluorine coating 12 is applied to the second surface of the back panel, with a thickness of 5~10 μm, for example, any one or a value between any two of 5, 6, 7, 8, 9, and 10 μm. The coating material is polyvinylidene fluoride and / or polytetrafluoroethylene. Figure 1 As shown, the second fluorine coating can improve the adhesion of the anti-black layer to the back panel body.

[0074] To improve reflectivity and further enhance aging resistance (yellowing resistance), in some specific embodiments, an anti-blackening layer 3 is attached to the surface of the second fluorine coating 12 away from the backplate body 1, with a thickness of 15~30μm, for example, any value or a range between 15, 18, 20, 22, 25, 28, and 30μm; Figure 1 As shown. This anti-black layer has excellent reflectivity to infrared light, for example, over 80%, and also optimizes the aging resistance of the back panel. By applying the aforementioned specific functional coatings to both the inner and outer sides of the back panel, the aging resistance of the back panel can be improved while maintaining good flame retardancy.

[0075] To improve the reflectivity of the anti-black layer, red, yellow, and blue pigments can be added to form a black or near-black coating. This coating is beneficial for reflecting infrared light, especially with an infrared reflectivity of over 80%, and is also known as a high-reflectivity layer. In some embodiments, the anti-black layer 3 contains red, yellow, and blue pigments, as well as a base resin and some other additives. When pure pigments are used for color mixing, the weight ratio of red, yellow, and blue pigments is (1~2):(3~3.5):(1~1.5), wherein the weight ratio of red pigment can be 1:1. The weight ratio of red, yellow, and blue pigments can be any value from 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, or any value between any two; the weight ratio of yellow pigment can be any value from 3, 3.1, 3.2, 3.3, 3.4, 3.5, or any value between any two; the weight ratio of blue pigment can be any value from 1, 1.1, 1.2, 1.3, 1.4, 1.5, or any value between any two; preferably, the weight ratio of red, yellow, and blue pigments is (1~1.6):(3~3.06):(1~1.03). By controlling the ratio of red, yellow, and blue pigments, not only can a coating with the best blackness be created, but also a coating with better infrared light reflection performance, the best reflectivity, and better resistance to yellowing can be ensured, thereby improving its energy utilization efficiency under various lighting conditions.

[0076] To improve the dispersibility of red, yellow, and blue pigments in resin, color masterbatches can be used. In some embodiments, the red pigment is derived from red masterbatch, the yellow pigment from yellow masterbatch, and the blue pigment from blue masterbatch, with particle sizes controllable between 100 and 500 nm. By adding color masterbatches, resin can be omitted. By mixing red, yellow, and blue masterbatches to form black, the stability and durability of the color can be improved, allowing for precise control of the color ratio. Color masterbatches not only contain pigments but also additives and resin carriers, which helps improve coating dispersibility, adhesion, and weather resistance, ensuring the coating has excellent overall performance.

[0077] To further improve the uniformity and dispersibility of pigments, the weight of red pigment in the red masterbatch can be limited to 10%~30% of the weight of the red masterbatch matrix resin, for example, any value or a range between 10%, 15%, 20%, 25%, and 30%; the weight of yellow pigment in the yellow masterbatch can be 10%~30% of the weight of the yellow masterbatch matrix resin, for example, any value or a range between 10%, 15%, 20%, 25%, and 30%; and the weight of blue pigment in the blue masterbatch can be 10%~30% of the weight of the blue masterbatch matrix resin, for example, any value or a range between 10%, 15%, 20%, 25%, and 30%. Using masterbatches with the above pigment contents ensures uniform pigment dispersion in the masterbatch resin, which is beneficial for coating uniformity. Appropriate pigment content is beneficial for coating hardness, toughness, and adhesion; it ensures a visually black appearance while improving infrared light reflectivity, thereby improving the energy conversion efficiency and lifespan of photovoltaic modules.

[0078] To further improve the aging resistance of the backsheet, color masterbatches with anti-aging matrix resins can be selected. In some embodiments, the matrix resin of the red masterbatch is acrylic resin; the matrix resin of the yellow masterbatch is acrylic resin; and the matrix resin of the blue masterbatch is acrylic resin. The selected acrylic color masterbatches have good aging resistance, further promoting the overall aging resistance of the backsheet.

[0079] According to a second aspect of this application, a method for preparing the aforementioned photovoltaic module backsheet is provided, comprising:

[0080] Step S1: The first fluorine material is applied to the first surface of the backplate body 1, and after the first curing, the first fluorine coating 11 is formed;

[0081] Step S2: A flame-retardant slurry is applied to the surface of the first fluorine coating 11 away from the backsheet body 1. After a second curing process, a flame-retardant layer 2 is formed, thereby obtaining the photovoltaic module backsheet. The flame-retardant slurry contains carbon black, and the carbon black content in the flame-retardant layer 2 is 0.2wt%~2wt%. The method described in this application is simple to operate, low in cost, and the prepared backsheet can simultaneously achieve good flame retardancy and aging resistance.

[0082] In some specific embodiments, the first curing temperature in step S1 is 130~150℃, for example, any value or a range between 130℃, 135℃, 140℃, 145℃, and 150℃; the first curing time is 3~5 minutes, for example, 3, 4, and 5 minutes. The second curing temperature in step S2 is 130~150℃, for example, any value or a range between 130℃, 135℃, 140℃, 145℃, and 150℃; the second curing time is 3~5 minutes, for example, 3, 4, and 5 minutes. Using the above curing temperatures and times helps to improve the curing speed and strength of the fluoropolymer coating and flame-retardant layer, enhancing the coating's adhesion and stability.

[0083] In some specific embodiments, the first fluorinated material is polyvinylidene fluoride and / or polytetrafluoroethylene; the thickness of the first fluorinated coating 11 is 5~10 μm; the thickness of the backplate body 1 is 250~280 μm; and the thickness of the flame-retardant layer 2 is 20~30 μm. Using the above-mentioned fluorinated materials helps to improve the adhesion of the flame-retardant layer to the backplate. Controlling the thicknesses of the fluorinated coating and the flame-retardant layer within the above-mentioned ranges helps to improve the overall aging resistance and flame retardancy of the backplate.

[0084] In some specific embodiments, the flame-retardant paste comprises the following components by weight: 120-125 parts of base resin, 55-110 parts of flame retardant, 5-10 parts of first curing agent, 190-210 parts of first diluent, 1-2 parts of first matting agent, 2-3 parts of additives, and 2-3 parts of carbon black; wherein, the weight parts of the base resin can be selected from any value of 120, 121, 122, 123, 124, or 125 parts, or any range between two; the weight parts of the flame retardant can be selected from 55, 60, 65, 70, 75, 80, or 85 parts. The weight percentages of the following components are selected: 90, 95, 100, 105, and 110 parts, or any value within a range of both; the weight percentages of the first curing agent are selected: 5, 6, 7, 8, 9, and 10 parts, or any value within a range of both; the weight percentages of the diluent are selected: 190, 195, 200, 205, and 210 parts, or any value within a range of both; the weight percentages of the first matting agent are selected: 1, 1.5, and 2.0 parts, or any value within a range of both; the additives are 2, 2.5, and 3 parts; and the carbon black is 2, 2.5, and 3 parts. By optimizing the flame-retardant slurry formulation, the backing sheet exhibits excellent flame-retardant properties, as well as superior aging resistance and good mechanical properties, making it suitable for complex environments with high temperature and high humidity.

[0085] In some specific embodiments, the flame retardant is selected from at least one of brominated flame retardants, phosphorus-based flame retardants, and nitrogen-based flame retardants; preferably, the brominated flame retardant is selected from at least one of decabromodiphenyl ether (Deca-BDE), hexabromocyclododecane (HBCD), and tetrabromobisphenol A (TBBPA); preferably, the phosphorus-based flame retardant is selected from at least one of phosphate esters (TCP, TPP), ammonium polyphosphate (APP), and phosphonates; preferably, the nitrogen-based flame retardant is selected from at least one of melamine, melamine cyanurate (MCA), and dicyandiamide. The selected flame retardants enable the back panel to achieve a UL94 VTM-0 flame retardant performance.

[0086] In some specific embodiments, the first curing agent is selected from at least one of ethylenediamine, diethylenetriamine, low molecular weight polyamide, Mannich base, cyclic aliphatic amine, phthalic anhydride, tetrahydrophthalic anhydride, HDI trimer, IPDI trimer, methyl ethyl ketone peroxide, benzoyl peroxide, KH-550, and KH-560. The selected curing agents improve the curing speed and strength of the flame-retardant layer, and enhance the adhesion and stability of the coating.

[0087] In some specific embodiments, the first diluent is selected from at least one of glycidyl acrylate (AGE), butyl glycidyl ether (BGE), neopentyl glycol diglycidyl ether (NGDE), trimethylolpropane triglycidyl ether (TMPGE), ethyl acetate, propylene glycol methyl ether acetate (PMA), acetone, butanone (MEK), toluene, xylene, isopropanol (IPA), butyl acetate, DBE (dicarboxylic acid ester mixture), cyclohexanone, 1,4-butanediol (BDO), and propylene carbonate (PC). The selected diluent can give the slurry a suitable viscosity, making it easy to flow and spread, and can also promote the mixing of raw materials.

[0088] In some specific embodiments, the first matting agent is selected from at least one of fumed silica, polyethylene wax (PE wax), polypropylene wax (PP wax), oxidized polyethylene wax, micronized wax, polymethyl urea resin, polyamide wax, kaolin, diatomaceous earth, and talc; the additives are selected from at least one of leveling agents, defoamers, and ultraviolet absorbers. By selecting appropriate types of each component, each exerts its optimal effect, jointly promoting the flame retardancy and aging resistance of the backsheet.

[0089] In some specific embodiments, step S2 is followed by step S3: applying a second fluorine material to the second surface of the backsheet body 1 opposite to the first surface, and then curing it to form a second fluorine coating 12. More preferably, the third curing temperature is 140~150℃, and the third curing time is 5~7 min; for example, 140, 145, or 150℃. Even more preferably, the thickness of the second fluorine coating 12 is 5~10 μm; the second fluorine coating is polyvinylidene fluoride and / or polytetrafluoroethylene. Applying a fluorine layer to the backsheet surface can improve the backsheet's resistance to ultraviolet radiation, temperature and humidity changes, extend the backsheet's service life, and ensure that the photovoltaic module maintains good performance and reliability under long-term outdoor conditions. By controlling the thickness of each layer, the overall performance of the backsheet can be improved.

[0090] In some specific embodiments, step S4 is included after step S3: applying an anti-blackening paste to the surface of the second fluorine coating 12 away from the backplate body 1, and forming an anti-blackening layer 3 after a fourth curing; the fourth curing temperature is 140~150℃, for example, any value among 140, 145, and 150℃ or any range between two; the fourth curing time is 5~7 minutes; the thickness of the anti-blackening layer 3 is 15~30μm, for example, any value among 15, 18, 20, 22, 25, 28, and 30μm or any range between two. By coating the second surface with an anti-blackening layer, the yellowing resistance of the backplate can be further improved in addition to improving the infrared reflectivity.

[0091] In some specific embodiments, the anti-black slurry contains red, yellow, and blue pigments; the weight ratio of red, yellow, and blue pigments is (1~2):(3~3.5):(1~1.5), preferably (1~1.6):(3~3.06):(1~1.03). When adding pure pigments, a base resin also needs to be added. The selection of the base resin is similar to that of the flame-retardant layer; an aging-resistant resin is sufficient. Alternatively, color masterbatches (pigment + resin) can be added directly. For example, red pigment is derived from red masterbatch, yellow pigment from yellow masterbatch, and blue pigment from blue masterbatch. The particle size of the color masterbatch is 100~500nm. By adjusting the proportion of each pure pigment in the slurry, a slurry that visually approximates black can be obtained, meeting the backsheet color requirements. Adding pigments in the form of color masterbatches improves pigment dispersibility, which is beneficial to the uniformity of the flame-retardant coating and promotes the aging resistance of the backsheet.

[0092] In some embodiments, the anti-black paste comprises the following components by weight: 18-36 parts red masterbatch, 54-63 parts yellow masterbatch, 18-27 parts blue masterbatch, 1-2 parts second matting agent, 10-12 parts second curing agent, and 12-16 parts second diluent; further, 18-28.2 parts red masterbatch, 54-55.08 parts yellow masterbatch, 18-18.54 parts blue masterbatch, 1.1-1.84 parts second matting powder, 11-1.5 parts second curing agent, and 13-15 parts second diluent. By adjusting the paste formulation, a paste close to black is obtained, which is beneficial for improving light reflectivity, promoting photoelectric conversion efficiency, and reducing light received by the backsheet, which also helps to improve the aging resistance of the backsheet.

[0093] In some specific embodiments, the weight of red pigment in the red masterbatch is 10% to 30% of the weight of the red masterbatch matrix resin; the weight of yellow pigment in the yellow masterbatch is 10% to 30% of the weight of the yellow masterbatch matrix resin; the weight of blue pigment in the blue masterbatch is 10% to 30% of the weight of the blue masterbatch matrix resin; the matrix resin of the red masterbatch is acrylic resin; the matrix resin of the yellow masterbatch is acrylic resin; and the matrix resin of the blue masterbatch is acrylic resin. Using masterbatches with the above-mentioned pigment contents ensures uniform pigment dispersion, which is beneficial for coating uniformity; it guarantees a visually black appearance while also improving the reflectivity of infrared light, thereby improving the energy conversion efficiency and lifespan of the photovoltaic module.

[0094] In some embodiments, the second matting agent is selected from at least one of fumed silica, polyethylene wax, polypropylene wax, oxidized polyethylene wax, micronized wax, polymethylurea resin, polyamide wax, kaolin, diatomaceous earth, and talc. The second curing agent is selected from at least one of ethylenediamine, diethylenetriamine, low molecular weight polyamide, Mannich base, cyclic aliphatic amine, phthalic anhydride, tetrahydrophthalic anhydride, hexamethylene diisocyanate trimer, isophorone diisocyanate trimer, methyl ethyl ketone peroxide, benzoyl peroxide, γ-aminopropyltriethoxysilane and γ-(2,3-epoxypropoxy)propyltrimethoxysilane, isocyanate, and epoxy-modified curing agents; the second diluent is selected from at least one of glycidyl acrylate, butyl glycidyl ether, neopentyl glycol diglycidyl ether, trimethylolpropane triglycidyl ether, ethyl acetate, propylene glycol methyl ether acetate, acetone, butanone, toluene, xylene, isopropanol, butyl acetate, cyclohexanone, 1,4-butanediol, and propylene carbonate. The second diluent is selected from at least one of glycidyl acrylate (AGE), butyl glycidyl ether (BGE), neopentyl glycol diglycidyl ether (NGDE), trimethylolpropane triglycidyl ether (TMPGE), ethyl acetate, propylene glycol methyl ether acetate (PMA), acetone, butanone (MEK), toluene, xylene, isopropanol (IPA), butyl acetate, DBE (dicarboxylic acid ester mixture), cyclohexanone, 1,4-butanediol (BDO), and propylene carbonate (PC).

[0095] According to a third aspect of this application, a photovoltaic module is provided, comprising, in sequence, a front glass panel, an upper encapsulating film, solar cells, a lower encapsulating film, and a rear backsheet; the solar cells are disposed between the front glass panel and the rear backsheet; wherein the backsheet is the photovoltaic module backsheet described above or a photovoltaic module backsheet prepared by the above-described preparation method. Preferably, the anti-black layer 3 of the backsheet body 1 is on the inner side, adjacent to the solar cells; the flame-retardant layer 2 of the backsheet body 1 is on the outer side, away from the solar cells, and in contact with the external environment.

[0096] The present application will be further described in detail below with reference to specific embodiments, which should not be construed as limiting the scope of protection claimed in the present application.

[0097] All raw materials used in the embodiments of this application are existing technologies and can be purchased.

[0098] Example 1

[0099] Step S1, Flame Retardant Slurry Composition: By weight, the matrix resin is 125 parts acrylic resin, the flame retardant is 100 parts ammonium polyphosphate, the first diluent is 200 parts propylene glycol methyl ether acetate (PMA), the first matting agent is 1.6 parts talc, the leveling agent is 2.7 parts polydimethylsiloxane, the carbon black is 2.5 parts (particle size is 300nm), and the first curing agent is 5 parts ethylenediamine.

[0100] Acrylic resin, propylene glycol methyl ether acetate, ammonium polyphosphate, and polydimethylsiloxane were mixed and stirred at high speed for 20 minutes in a disperser to prepare a pigment paste. Then, matting agent and carbon black were added to the pigment paste to adjust the color, and ethylenediamine was added and stirred to obtain a flame retardant paste. The flame retardant paste was coated on the first surface of a CPC backing sheet (thickness of 270 μm), and the coating thickness was controlled to be about 30 μm. It was then placed in a 150°C oven for 5 minutes to form a flame retardant layer 2. The CPC backing sheet was prepared by coating polyvinylidene fluoride on the first and second surfaces of the backing sheet body 1 (PET), and after curing, a first fluorine coating 11 and a second fluorine coating 12 were formed, each with a coating thickness of 10 μm. The flame retardant layer 2 was attached to the surface of the first fluorine coating 11.

[0101] Step S2, Anti-blackening slurry: 27 parts of red acrylic resin masterbatch (containing 10wt% red pigment, particle size 200nm), 58 parts of yellow acrylic resin masterbatch (containing 10wt% yellow pigment, particle size 200nm), 27 parts of blue acrylic resin masterbatch (containing 10wt% yellow pigment, particle size 200nm), 1 part of the second matting agent talc, and 14 parts of the second diluent propylene glycol methyl ether acetate are mixed and stirred at high speed for 20 minutes in a disperser; then 12 parts of the second curing agent ethylenediamine are added and stirred to obtain the anti-blackening slurry. The anti-blackening slurry is then coated onto the surface of the second fluorine coating 12 of the CPC backplate in step S1, controlling the coating thickness to about 30μm, and cured in a 150℃ oven for 5 minutes to form the anti-blackening layer 3; the overall structure of the backplate is as follows. Figure 1 As shown.

[0102] Example 2

[0103] Step S1, Flame Retardant Slurry Composition: By weight, the matrix resin is 125 parts acrylic resin, the diluent is 200 parts propylene glycol methyl ether acetate (PMA), the flame retardant is 100 parts aluminum diethylphosphinate (OP935), the leveling agent is polydimethylsiloxane, the first matting agent is 1.6 parts talc, the first matting agent is 2.5 parts carbon black (particle size of 300nm), and the first curing agent is ethylenediamine 5 parts.

[0104] Acrylic resin, propylene glycol methyl ether acetate, OP935, and polydimethylsiloxane were mixed and stirred at high speed for 20 minutes in a disperser to prepare a pigment paste. Talc and carbon black were then added to the pigment paste for varnishing, followed by the addition of ethylenediamine and stirring to obtain a flame-retardant paste. This flame-retardant paste was coated onto the first surface of a CPC backsheet (260 μm thick), with the coating thickness controlled to be approximately 25 μm. The coating was then cured in a 150°C oven for 5 minutes to form a flame-retardant layer 2. The CPC backsheet was prepared by coating polyvinylidene fluoride onto the first and second surfaces of the backsheet body 1 (PET), respectively. After curing, a first fluorine coating 11 and a second fluorine coating 12 were formed, each with a coating thickness of 5 μm. The flame-retardant layer 2 was attached to the surface of the first fluorine coating 11.

[0105] Step S2, Anti-blackening slurry composition: 27 parts of red acrylic resin masterbatch (containing 10wt% red pigment), 58 parts of yellow acrylic resin masterbatch (containing 10wt% yellow pigment), 27 parts of blue acrylic resin masterbatch (containing 10wt% yellow pigment), 1 part of the second matting agent talc, and 14 parts of the second diluent propylene glycol methyl ether acetate are mixed and stirred at high speed for 20 minutes in a disperser; then 11 parts of the second curing agent ethylenediamine are added and stirred to obtain the anti-blackening slurry. The anti-blackening slurry is then coated onto the surface of the second fluorine coating 12 of the CPC backplate in step S1, with a thickness controlled at approximately 20 μm, and cured in a 150℃ oven for 5 minutes to form the anti-blackening layer 3; the backplate structure is as follows. Figure 1 As shown.

[0106] Example 3

[0107] Step S1: Flame retardant slurry composition: by weight, 120 parts of base resin acrylic resin, 190 parts of diluent propylene glycol methyl ether acetate (PMA), 100 parts of flame retardant polypentyltetraphosphate (PEPA), 2 parts of leveling agent polydimethylsiloxane, 2 parts of first matting agent talc, 2.5 parts of carbon black (particle size 300nm), and 10 parts of first curing agent ethylenediamine.

[0108] Acrylic resin, propylene glycol methyl ether acetate, PEPA, and polydimethylsiloxane were mixed and stirred at high speed for 20 minutes in a disperser to prepare a pigment paste. Then, matting powder and carbon black were added to the pigment paste to adjust the color, and ethylenediamine was added and stirred to obtain a flame retardant paste. The flame retardant paste was coated on the first surface of a CPC backing sheet (thickness of 296 μm), and the coating thickness was controlled to be about 20 μm. It was then placed in a 150°C oven for 5 minutes to form a flame retardant layer 2. The CPC backing sheet was prepared by coating polyvinylidene fluoride on the first and second surfaces of the backing sheet body 1 (PET), and after curing, a first fluorine coating 11 and a second fluorine coating 12 were formed, each with a coating thickness of 8 μm. The flame retardant layer 2 was attached to the surface of the first fluorine coating 11.

[0109] Step S2, Anti-blackening slurry composition: 27 parts of red acrylic resin masterbatch (containing 10wt% red pigment), 58 parts of yellow acrylic resin masterbatch (containing 10wt% yellow pigment), 27 parts of blue acrylic resin masterbatch (containing 10wt% yellow pigment), 1 part of the second matting agent talc, and 14 parts of the second diluent propylene glycol methyl ether acetate are mixed and stirred at high speed for 20 minutes in a disperser; then 10 parts of the second curing agent ethylenediamine are added and stirred to obtain the anti-blackening slurry. The anti-blackening slurry is then coated onto the surface of the second fluorine coating 12 of the CPC backplate in step S1, with a thickness controlled at approximately 15μm, and cured in a 150℃ oven for 5 minutes to form the anti-blackening layer 3; the backplate structure is as follows. Figure 1 As shown.

[0110] Example 4

[0111] Example 4 differs from Example 1 in that the weight percentage of carbon black in step S1 is replaced with 0.88 parts (the carbon black accounts for 0.20 wt% of the flame retardant layer); all other operations are the same; the backplate structure is as follows. Figure 1 As shown.

[0112] Example 5

[0113] Example 5 differs from Example 1 in that the weight percentage of carbon black in step S1 is replaced with 8.86 parts (the carbon black accounts for 2 wt% of the flame retardant layer); all other operations are the same; the backplate structure is as follows. Figure 1 As shown.

[0114] Example 6

[0115] Example 6 differs from Example 1 in that the weight percentage of carbon black in step S1 is replaced with 1.75 parts (the carbon black accounts for 0.4 wt% of the flame retardant layer); all other operations are the same; the backplate structure is as follows. Figure 1 As shown.

[0116] Example 7

[0117] Example 7 differs from Example 1 in that the weight percentage of carbon black in step S1 is replaced with 3.5 parts (the carbon black accounts for 0.8 wt% of the flame retardant layer); all other operations are the same; the backplate structure is as follows. Figure 1 As shown.

[0118] Example 8

[0119] Example 8 differs from Example 1 in that the particle size of the carbon black in step S1 is replaced with 500 nm; all other operations are the same; the backplate structure is as follows. Figure 1 As shown.

[0120] Example 9

[0121] Example 9 differs from Example 1 in that the flame retardant in step S1 is replaced with tetrabromobisphenol A; all other operations are the same; the backplate structure is as follows. Figure 1 As shown.

[0122] Example 10

[0123] Example 10 differs from Example 1 in that the flame retardant in step S1 is replaced with melamine; all other operations are the same; the backplate structure is as follows. Figure 1 As shown.

[0124] Example 11

[0125] Example 11 differs from Example 1 in that 100 parts of ammonium polyphosphate in step S1 are replaced with 60 parts; all other operations are the same; the backplate structure is as follows. Figure 1 As shown.

[0126] Example 12

[0127] Example 12 differs from Example 1 in that 100 parts of ammonium polyphosphate in step S1 are replaced with 80 parts; all other operations are the same; the backplate structure is as follows. Figure 1 As shown.

[0128] Example 13

[0129] Example 13 differs from Example 1 in that the pigment content in the red acrylic masterbatch, blue acrylic masterbatch, and yellow acrylic masterbatch in step S2 is replaced with 20wt%; other operations are the same; the backplate structure is as follows. Figure 1 As shown.

[0130] Example 14

[0131] Example 14 differs from Example 1 in that the pigment content in the red acrylic resin masterbatch, blue acrylic resin masterbatch, and yellow acrylic resin masterbatch in step S2 is replaced with 30wt%; other operations are the same; the backplate structure is as follows. Figure 1 As shown.

[0132] Example 15

[0133] Example 15 differs from Example 1 in that the red acrylic resin masterbatch in step S2 is replaced with 18 parts, the blue acrylic resin masterbatch with 54 parts, and the pigment content in the yellow acrylic resin masterbatch is replaced with 18 parts; all other operations are the same; the backplate structure is as follows. Figure 1 As shown.

[0134] Example 16

[0135] Example 16 differs from Example 1 in that the red acrylic resin masterbatch in step S2 is replaced with 36 parts, the blue acrylic resin masterbatch with 63 parts, and the pigment content in the yellow acrylic resin masterbatch is replaced with 27 parts; all other operations are the same; the backplate structure is as follows. Figure 1 As shown.

[0136] Example 17

[0137] The difference between Example 17 and Example 1 is that the second surface of the back panel body 1 is not coated with the second fluorine coating 12 and the anti-black layer 3;

[0138] Specific method: Acrylic resin, propylene glycol methyl ether acetate, ammonium polyphosphate, and polydimethylsiloxane are mixed and stirred at high speed for 20 minutes in a disperser to prepare a pigment paste; talc is added to the pigment paste for color adjustment, and then ethylenediamine is added and stirred to obtain a flame-retardant paste; this flame-retardant paste is coated on the first surface of the backing plate body (PET), controlling the coating thickness to be about 30 μm, and then cured in a 150℃ oven for 5 minutes to form a flame-retardant layer 2; wherein, the first surface of the backing plate body (PET) has been coated with polyvinylidene fluoride, which, after curing, forms a first fluorine coating 11 with a coating thickness of 10 μm; the flame-retardant layer 2 is attached to the surface of the first fluorine coating 11; its structure is as follows. Figure 2 As shown.

[0139] Comparative Example 1

[0140] The difference between Comparative Example 1 and Example 1 is that the flame-retardant slurry does not contain carbon black; other operations are the same; the backplate structure is as follows. Figure 1 As shown.

[0141] Comparative Example 2

[0142] The difference between Comparative Example 2 and Example 1 is that the weight percentage of carbon black in step S1 is replaced with 0.7 parts (the proportion of carbon black in the flame retardant layer is 0.16 wt%); other operations are the same; the backplate structure is as follows. Figure 1 As shown.

[0143] Comparative Example 3

[0144] The difference between Comparative Example 3 and Example 1 is that the weight percentage of carbon black in step S1 is replaced with 10 parts (the carbon black accounts for 2.25 wt% of the flame retardant layer); other operations are the same; the backplate structure is as follows. Figure 1 As shown.

[0145] Comparative Example 4

[0146] The difference between Comparative Example 4 and Example 1 is that neither the first fluorine coating 11 nor the second fluorine coating 12 are applied to the first and second surfaces of the backsheet body 1 (PET), but instead, a flame-retardant layer and an anti-blackening layer are directly applied to the PET backsheet; all other operations are the same; the backsheet structure is as follows. Figure 3 As shown.

[0147] Performance testing:

[0148] 1. The D90 particle size was tested and analyzed using a laser particle size analyzer. The specific testing steps are as follows:

[0149] (1) Preparation before testing: Understand the chemical and physical properties of the sample (solubility, density, toxicity, refractive index); select a transparent liquid that does not dissolve the sample (water, ethanol, isopropanol, etc.), whose refractive index should be different from that of the sample;

[0150] (2) Instrument preparation and background measurement: Turn on the laser particle size analyzer and the circulating dispersion system to preheat; the software performs background measurement. At this time, inject sufficient pure dispersion medium into the sample cell and start circulation and ultrasonication; the instrument measures the scattered light signal of the current pure medium as "background noise". This background will be deducted in subsequent sample measurements to ensure data purity.

[0151] (3) Sample addition and dispersion: Take a small amount of representative sample; initially wet and stir the sample in a beaker with a small amount of medium and dispersant; slowly add the pre-dispersed liquid to the circulating sample cell and observe the light-blocking rate or concentration displayed in real time by the software to make it reach the optimal range recommended by the instrument (usually 8%-20%); turn on ultrasonic and mechanical stirring, and use the cavitation effect of ultrasonic to break up soft agglomerates.

[0152] (4) Formal measurement: When the shading rate is stable and the real-time particle size distribution curve no longer changes, the system reaches stability; start the measurement program, the instrument will automatically measure 3-5 times continuously and calculate the average value, and at the same time give the complete volume distribution curve and each characteristic value (D90 is the particle size corresponding to the cumulative volume distribution reaching 90%).

[0153] (5) Data recording and system cleaning: Record the data and attach detailed dispersion conditions (medium, dispersant, ultrasonic power and time); after the test, the circulation pipeline and sample cell must be thoroughly cleaned to prevent cross-contamination.

[0154] 2. The performance of the backsheets of the photovoltaic modules prepared in Examples 1-17 and Comparative Examples 1-4 was tested using the PCT damp heat aging test method, a spectrophotometer (to test the b-value of the sample), and an ultraviolet-visible-near-infrared spectrophotometer (to test reflectance).

[0155] 2-1. PCT damp heat aging test: The test conditions for PCT aging are a temperature of 121℃, 100% humidity, and a pressure range of 0.02~0.2 MPa (gauge pressure).

[0156] (1) Sample preparation: Ensure that the sample is representative and that the surface is clean and free of contamination;

[0157] (2) Initial performance testing: Establish a performance baseline for comparison after aging;

[0158] (3) Place the sample and set the above test conditions;

[0159] (4) Start testing and cycle setting: Set 24 hours as a cycle, and then carry out aging test.

[0160] 2-2. Spectrophotometer test of sample b-value:

[0161] (1) Instrument calibration: Zero point calibration and white calibration are performed using the included whiteboard and blackboard (or standard tiles). This is a necessary step before each power-on measurement.

[0162] (2) Sample preparation: The surface must be clean, flat, free of scratches and contamination;

[0163] (3) Set measurement parameters: Use an integrating sphere with a d / 8° angle and an incandescent lamp;

[0164] (4) Establish a standard sample: Measure and save the color data of the standard sample as a benchmark;

[0165] (5) Measure the sample.

[0166] 2-3. Reflectance testing using an ultraviolet-visible-near-infrared spectrophotometer:

[0167] (1) Calibration: Calibration is performed using a standard reflective white plate and black screen;

[0168] (2) Sample preparation: The surface must be clean and flat;

[0169] (3) Select parameters: The test wavelength range is 250-1100nm;

[0170] (4) Measure the baseline;

[0171] (5) Conduct sample testing.

[0172] The results are shown in Table 1.

[0173] Table 1

[0174]

[0175] Table 1 shows the test results. The photovoltaic module backsheets of the various embodiments of this application achieve UL94 VTM-0 flame retardant performance by setting a flame retardant layer on the backsheet surface. The addition of 0.2wt% to 2wt% carbon black material to the flame retardant layer significantly improves the aging resistance of the backsheet. The PCT test shows that its aging resistance is significantly higher than that of Comparative Examples 1 to 3. Although Comparative Examples 2 and 3 added carbon black, the amount added was not appropriate, and the aging resistance was still lower than that of the embodiments of this application.

[0176] This application achieves this by setting a flame-retardant layer 2 and an anti-blackening layer 3 on the surface of the back panel, such as Figure 1 As shown, the backsheet has significantly improved infrared light reflectivity and aging resistance. When the two surfaces of the backsheet of this application have a flame-retardant layer 2 and an anti-black layer 3 respectively, the infrared light reflectivity reaches 80%~88%. The anti-black layer has excellent infrared light reflectivity and also has the effect of optimizing the aging resistance of the backsheet. By setting this specific functional coating on the inner and outer sides of the backsheet, the aging resistance of the backsheet can be improved together, so that the photovoltaic module backsheet can simultaneously take into account both excellent aging resistance and infrared light reflectivity.

[0177] It should be noted that the terms "first," "second," etc., used in the specification and claims of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such terms can be used interchangeably where appropriate so that the embodiments of this application described herein can be implemented, for example, in a sequence other than those described herein.

[0178] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A photovoltaic module backsheet, comprising a backsheet body (1); characterized in that, The back panel body (1) has a first surface and a second surface opposite to each other; a first fluorine coating (11) is attached to the first surface, and a flame retardant layer (2) is attached to the surface of the first fluorine coating (11) away from the back panel body (1); wherein the flame retardant layer (2) contains carbon black, and the content of carbon black in the flame retardant layer (2) is 0.2wt%~2wt%.

2. The photovoltaic module backsheet according to claim 1, characterized in that, The thickness of the backplate body (1) is 250~280μm; And / or, the thickness of the first fluorine coating (11) is 5~10 μm; And / or, the thickness of the flame retardant layer (2) is 20~30μm; And / or, the particle size D90 of the carbon black is 300~500nm; And / or, the carbon black content in the flame-retardant layer (2) is 0.4wt%~0.8wt%; And / or, the material of the first fluorine coating (11) is polyvinylidene fluoride and / or polytetrafluoroethylene; And / or, the second surface is coated with a second fluorine coating (12).

3. The photovoltaic module backsheet according to claim 2, characterized in that, The thickness of the second fluorine coating (12) is 5~10 μm; And / or, the material of the second fluorine coating (12) is polyvinylidene fluoride and / or polytetrafluoroethylene; And / or, an anti-black layer (3) is attached to the surface of the second fluorine coating (12) away from the backplate body (1). Preferably, the thickness of the anti-black layer (3) is 15~30μm; Preferably, the anti-black layer (3) contains red pigment, yellow pigment and blue pigment; More preferably, the weight ratio of the red pigment, the yellow pigment and the blue pigment is (1~2):(3~3.5):(1~1.5).

4. The photovoltaic module backsheet according to claim 3, characterized in that, The red pigment is derived from red masterbatch, the yellow pigment is derived from yellow masterbatch, and the blue pigment is derived from blue masterbatch; Preferably, the particle sizes of the red masterbatch, the yellow masterbatch, and the blue masterbatch are 100~500nm, respectively; Preferably, the matrix resin of the red masterbatch, the matrix resin of the yellow masterbatch, and the matrix resin of the blue masterbatch are all acrylic resins. Preferably, the red pigment in the red masterbatch is 10wt% to 30wt% of the matrix resin of the red masterbatch; Preferably, the yellow pigment in the yellow masterbatch is 10wt% to 30wt% of the matrix resin of the yellow masterbatch; Preferably, the blue pigment in the blue masterbatch is 10wt% to 30wt% of the matrix resin of the blue masterbatch.

5. A method for preparing a photovoltaic module backsheet according to any one of claims 1 to 4, characterized in that, include: Step S1: Apply the first fluorine material to the first surface of the back plate body (1), and form the first fluorine coating (11) after the first curing. Step S2: Apply flame retardant slurry to the surface of the first fluorine coating (11) away from the backsheet body (1), and after a second curing, form a flame retardant layer (2) to obtain the photovoltaic module backsheet; wherein, the flame retardant slurry contains carbon black, and the content of carbon black in the flame retardant layer (2) is 0.2wt%~2wt%.

6. The method for preparing a photovoltaic module backsheet according to claim 5, characterized in that, The second curing temperature is 130~150℃, and the second curing time is 3~5 minutes; And / or, the flame retardant slurry comprises the following components: by weight, 120-125 parts of matrix resin, 55-110 parts of flame retardant, 5-10 parts of first curing agent, 190-210 parts of first diluent, 1-2 parts of first matting agent, 2-3 parts of additives, and 2-3 parts of carbon black. And / or, the particle size D90 of the carbon black is 300~500nm; And / or, the first fluorinated material is polyvinylidene fluoride and / or polytetrafluoroethylene; And / or, the thickness of the first fluorine coating (11) is 5~10 μm; And / or, the thickness of the backplate body (1) is 250~280μm; And / or, the thickness of the flame retardant layer (2) is 20~30μm.

7. The method for preparing a photovoltaic module backsheet according to claim 6, characterized in that, The matrix resin is selected from at least one of acrylic resin, epoxy resin, phenolic resin, polyurethane, silicone resin and polyolefin resin; And / or, the flame retardant is selected from at least one of brominated flame retardants, phosphorus-based flame retardants, and nitrogen-based flame retardants; preferably, the brominated flame retardant is selected from at least one of decabromodiphenyl ether, hexabromocyclododecane, and tetrabromobisphenol A; preferably, the phosphorus-based flame retardant is selected from at least one of phosphate esters, ammonium polyphosphate, and phosphonates; preferably, the nitrogen-based flame retardant is selected from at least one of melamine, melamine cyanurate, and dicyandiamide; And / or, the first curing agent is selected from at least one of ethylenediamine, diethylenetriamine, polyamide, Mannich base, cyclic aliphatic amine, phthalic anhydride, tetrahydrophthalic anhydride, hexamethylene diisocyanate trimer, isophorone diisocyanate trimer, methyl ethyl ketone peroxide, benzoyl peroxide, γ-aminopropyltriethoxysilane, and γ-(2,3-epoxypropoxy)propyltrimethoxysilane; And / or, the first diluent is selected from at least one of glycidyl acrylate, butyl glycidyl ether, neopentyl glycol diglycidyl ether, trimethylolpropane triglycidyl ether, ethyl acetate, propylene glycol methyl ether acetate, acetone, butanone, toluene, xylene, isopropanol, butyl acetate, cyclohexanone, 1,4-butanediol, and propylene carbonate. And / or, the first matting agent is selected from at least one of fumed silica, polyethylene wax, polypropylene wax, oxidized polyethylene wax, micronized wax, polymethylurea resin, polyamide wax, kaolin, diatomaceous earth and talc. And / or, the additive is selected from at least one of leveling agents, defoamers and ultraviolet absorbers.

8. The method for preparing a photovoltaic module backsheet according to claim 6 or 7, characterized in that, Step S2 is followed by step S3: applying the second fluorine material to the second surface of the backplate body (1) opposite to the first surface, and forming the second fluorine coating (12) after a third curing. Preferably, step S3 is followed by step S4: applying anti-black slurry to the surface of the second fluorine coating (12) away from the back plate body (1), and forming an anti-black layer (3) after a fourth curing. Preferably, the fourth curing temperature is 140~150℃, and the fourth curing time is 5~7 minutes; Preferably, the thickness of the second fluorine coating (12) is 5~10 μm; Preferably, the thickness of the anti-black layer (3) is 15~30μm; Preferably, the second fluorinated material is polyvinylidene fluoride and / or polytetrafluoroethylene; Preferably, the anti-blackening paste contains red pigment, yellow pigment, and blue pigment; More preferably, the weight ratio of the red pigment, the yellow pigment, and the blue pigment is (1~2):(3~3.5):(1~1.5); even more preferably, the red pigment is derived from red masterbatch, the yellow pigment is derived from yellow masterbatch, and the blue pigment is derived from blue masterbatch; More preferably, the anti-blackening paste comprises the following components: by weight, 18-36 parts of red masterbatch, 54-63 parts of yellow masterbatch, 18-27 parts of blue masterbatch, 1-2 parts of second matting agent, 10-12 parts of second curing agent, and 12-16 parts of second diluent.

9. The method for preparing a photovoltaic module backsheet according to claim 8, characterized in that, The red masterbatch, the yellow masterbatch, and the blue masterbatch have particle sizes of 100~500nm, respectively. And / or, the red pigment is 10wt% to 30wt% of the matrix resin of the red masterbatch; And / or, the yellow pigment is 10wt% to 30wt% of the matrix resin of the yellow masterbatch; And / or, the blue pigment is 10wt% to 30wt% of the matrix resin of the blue masterbatch; And / or, the matrix resin of the red masterbatch, the matrix resin of the yellow masterbatch, and the matrix resin of the blue masterbatch are all acrylic resins; And / or, the second matting agent is selected from at least one of fumed silica, polyethylene wax, polypropylene wax, oxidized polyethylene wax, micronized wax, polymethylurea resin, polyamide wax, kaolin, diatomaceous earth and talc. And / or, the second curing agent is selected from at least one of ethylenediamine, diethylenetriamine, low molecular weight polyamide, Mannich base, cyclic aliphatic amine, phthalic anhydride, tetrahydrophthalic anhydride, hexamethylene diisocyanate trimer, isophorone diisocyanate trimer, methyl ethyl ketone peroxide, benzoyl peroxide, γ-aminopropyltriethoxysilane and γ-(2,3-epoxypropoxy)propyltrimethoxysilane, isocyanates and epoxy-modified curing agents; And / or, the second diluent is selected from at least one of glycidyl acrylate, butyl glycidyl ether, neopentyl glycol diglycidyl ether, trimethylolpropane triglycidyl ether, ethyl acetate, propylene glycol methyl ether acetate, acetone, butanone, toluene, xylene, isopropanol, butyl acetate, cyclohexanone, 1,4-butanediol, and propylene carbonate.

10. A photovoltaic module, comprising a front glass panel, an upper encapsulating film, solar cells, a lower encapsulating film, and a rear backsheet; characterized in that, The backsheet is a photovoltaic module backsheet prepared by any one of claims 1 to 4 or any one of claims 5 to 9.

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