Light-conversion adhesive film for photovoltaic module and preparation method of light-conversion adhesive film
By preparing Eu3+-doped La2O3-based composite photoconverter powder and performing interfacial chemical modification via co-precipitation-calcination, the ultraviolet sensitivity problem of HJT batteries was solved, achieving efficient conversion of ultraviolet light to red light and improving module power.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-30
- Publication Date
- 2026-04-14
AI Technical Summary
Existing light transfer film technology cannot effectively protect HJT cells from ultraviolet damage, and cannot efficiently convert ultraviolet light into beneficial visible light, resulting in module power decay and reduced utilization.
Eu3+ uniformly doped La2O3-based composite photoconverter powder was prepared by coprecipitation-calcination method. A stable inorganic-organic hybrid structure was constructed by free radical graft copolymerization and amine intercalation modification of zirconium phosphate, achieving efficient and stable conversion and nanoscale dispersion of ultraviolet light.
It achieves efficient conversion of ultraviolet light to red light, improves the spectral utilization and long-term weather resistance of photovoltaic modules, and ensures the power stability and efficiency of modules under ultraviolet irradiation conditions.
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Abstract
Description
Technical Field
[0001] This invention relates to the field of light transfer film technology, specifically to a light transfer film for photovoltaic modules and its preparation method. Background Technology
[0002] With the booming development of the photovoltaic industry, breakthroughs have been continuously achieved in various photovoltaic cell technologies, and the photoelectric conversion efficiency of crystalline silicon cells has been continuously improved. The conversion efficiency of conventional monocrystalline PERC cells has approached its theoretical limit, and the room for future technological improvement is limited. Heterojunction (HJT) cells, with their high conversion efficiency and outstanding advantages such as low light-induced degradation, low temperature coefficient, and high bifaciality, have become a new direction for the development of crystalline silicon cells. However, existing HJT cells use amorphous or microcrystalline silicon technology, and their surfaces are extremely sensitive to ultraviolet radiation due to the presence of Si-H groups. Ultraviolet light easily damages their structure and produces defects, leading to module power degradation. To address this problem, the current market generally uses ultraviolet-blocking encapsulation films to physically shield and protect the cells. However, this solution directly blocks ultraviolet energy, inevitably causing a significant decrease in module power.
[0003] Therefore, developing a novel encapsulation material that can effectively protect HJT cells from UV damage and efficiently convert harmful UV light into beneficial visible light—namely, a UV-resistant transfer film—has become crucial for improving the performance of HJT modules. An ideal transfer film needs to convert the module's weak UV spectral response into a strong visible light spectral response (such as red light), thereby protecting the cells while improving solar energy utilization and achieving a power gain for the module.
[0004] However, existing conventional light transfer film technologies face severe challenges. Most technical approaches are limited to directly incorporating light conversion powder into the film matrix or simply physically compounding it with a direct absorber. The former has serious drawbacks: during processing and use, the inherent peroxide crosslinking agents and other chemicals within the film, along with the synergistic effects of water, oxygen, and ultraviolet radiation in harsh outdoor environments, easily attack and damage the crystal structure or luminescent centers of the light transfer material, leading to rapid degradation of its light conversion efficiency and insufficient lifespan. While simple compounding methods can provide some protection through ultraviolet absorbers, they still essentially sacrifice some of the opportunity to utilize ultraviolet light, limiting the improvement in conversion efficiency and power, and failing to fully realize the high-efficiency potential of HJT batteries.
[0005] In summary, the market urgently needs a phototransfer film solution that requires the phototransfer material itself to have excellent stability, and also needs to fundamentally solve the compatibility issues between the phototransfer material and the polymer matrix and various additives from the material system design. Summary of the Invention
[0006] The purpose of this invention is to provide a light transfer film for photovoltaic modules and its preparation method, so as to solve the problems raised in the prior art.
[0007] To achieve the above objectives, the present invention provides the following technical solution: Step 1: Add nitric acid and europium oxide to deionized water and stir. Add lanthanum nitrate hexahydrate, stir and add ammonia dropwise in a water bath to adjust the pH of the solution. Continue stirring, filter, and dry to obtain a mixture. Heat the mixture and calcine to obtain composite light conversion powder. Step 2: Dilute vinyltris(2-methoxyethoxy)silane with an aqueous ethanol solution and spray it evenly onto the surface of the composite light conversion powder to obtain pretreated composite light conversion powder; Step 3: Put the modified ethylene-vinyl acetate copolymer resin into a mixer, add pretreated composite light conversion powder, crosslinking agent, co-crosslinking agent, ultraviolet light absorber and modified zirconium phosphate, mix evenly, put into a casting machine, and make a light transfer film for photovoltaic modules through plasticizing extrusion, stretching, traction and winding.
[0008] Furthermore, in step 1, the deionized water, nitric acid, europium oxide, and lanthanum nitrate hexahydrate are mixed in a mass ratio of 100:3:0.006:0.5; in step 2, vinyltris(2-methoxyethoxy)silane is diluted with an aqueous ethanol solution in a volume ratio of 1:19, and the mass ratio of the composite light conversion powder to the vinyltris(2-methoxyethoxy)silane dilution is 1:2.
[0009] Furthermore, the mass concentration of the ethanol aqueous solution in step 2 is 95%.
[0010] Furthermore, the composition of the photovoltaic module light conversion film in step 3, by mass percentage, includes 0.1%~0.2% pretreated composite light conversion powder, 2%~4% crosslinking agent, 0.2%~0.4% co-crosslinking agent, 0.1%~0.2% ultraviolet light absorber, 2.5%~3.5% modified zirconium phosphate, and the balance is modified ethylene-vinyl acetate copolymer resin.
[0011] Furthermore, the crosslinking agent is 2,5-dimethyl-2,5-bis(tert-butylperoxide)hexane, the co-crosslinking agent is triallyl isocyanurate, and the ultraviolet absorber is benzophenone.
[0012] Furthermore, in step 1, the water bath temperature is 55~65℃, the pH value is adjusted to 8.9~9.1, stirring is continued for 0.5~1.5h, the drying temperature is 145~155℃, the heating and calcining temperature is 750~850℃, and the time is 1~3h; in step 3, the plasticizing extrusion temperature is 80~90℃.
[0013] Furthermore, the preparation steps of the modified ethylene-vinyl acetate copolymer resin are as follows: S1: Under a nitrogen atmosphere, ethylene-vinyl acetate copolymer resin, maleic anhydride, benzoyl peroxide and toluene are mixed, heated to 55~65℃, stirred for 15~25min, heated to 70~80℃ and reacted for 7~8h, then dropped into ice-cold methanol and stirred, filtered, washed with acetone and dried under vacuum to obtain the grafted ethylene-vinyl acetate copolymer resin. S2: Dry the grafted ethylene-vinyl acetate copolymer resin at 70~80℃ for 23~25h, add toluene, heat under reflux, filter, add the filtrate dropwise into acetone and stir, filter and dry to obtain the modified ethylene-vinyl acetate copolymer resin.
[0014] Furthermore, in S1, the mass ratio of the ethylene-vinyl acetate copolymer resin, maleic anhydride, benzoyl peroxide, and toluene is 1:5.34:0.55:50; in S2, the mass ratio of the grafted ethylene-vinyl acetate copolymer resin to toluene is 1:50.
[0015] Furthermore, the preparation steps of the modified zirconium phosphate are as follows: Zirconium phosphate, isooctylamine, and anhydrous ethanol were mixed, sealed, and reacted on a magnetic stirrer for 9-11 hours to obtain a mixture. The mixture was then transferred to a petri dish and allowed to stand for separation. After removing the supernatant, the mixture was dried in a vacuum oven at 45-55°C for 47-49 hours to obtain modified zirconium phosphate.
[0016] Furthermore, the zirconium phosphate, isooctylamine, and anhydrous ethanol are mixed in a mass ratio of 0.5:1:1.5.
[0017] Compared with the prior art, the beneficial effects of the present invention are: 1. This invention describes a light transfer film for photovoltaic modules and its preparation method, which uses a co-precipitation-calcination method to prepare Eu... 3+ Uniformly doped La2O3-based composite light-converting powder achieves efficient and stable conversion of ultraviolet light. Secondly, maleic anhydride is grafted onto the ethylene-vinyl acetate copolymer (EVA) backbone via free radical graft copolymerization, introducing strongly polar anchoring sites. Simultaneously, amine intercalation surface modification organically modifies zirconium phosphate, significantly improving the interfacial compatibility between the two inorganic fillers and the polymer matrix. Finally, during casting and subsequent lamination, peroxide-induced free radical crosslinking and silane coupling agent interfacial condensation coupling reactions occur simultaneously, forming a chemically bonded, three-dimensional network composite material. Through precise interfacial chemical modification (grafting, intercalation, and coupling), the functional fillers (composite light-converting powder and zirconium phosphate) are uniformly dispersed and firmly anchored at the nanoscale in the matrix, resulting in excellent light conversion efficiency, high transmittance, and long-term weather resistance.
[0018] 2. The photovoltaic module phototransfer film and its preparation method described in this invention, at the level of interfacial chemical synergy, construct a stable inorganic-organic hybrid structure through multi-level covalent bonding. On one hand, the maleic anhydride groups grafted onto the modified EVA resin and the amine groups of the organic zirconium phosphate intercalation layer undergo a condensation reaction during the thermal processing of photovoltaic module encapsulation lamination, generating imide bonds (-CO-NH-CO-) in situ, covalently connecting the zirconium phosphate sheets to the polymer backbone; on the other hand, the silane coupling agent, through alkoxy hydrolysis condensation and vinyl copolymerization reaction, establishes covalent bonds on the surface of the composite phototransfer powder and between the crosslinked networks. These two parallel and complementary interfacial reactions jointly construct a three-dimensional interpenetrating network of "polymer-filler-filler" linked by covalent bonds. Based on this covalent interface, the system achieves structure-function synergy: the cross-linked three-dimensional network framework chemically anchors the composite light-converting powder (responsible for converting ultraviolet to red light) to the layered zirconium phosphate (providing nanoscale barriers), thus stabilizing and protecting the light-converting active centers. Simultaneously, the tortuous paths formed by the layered fillers effectively block water and oxygen permeation, achieving a balance between functional durability and structural stability. The spectrum conversion function of the composite light-converting powder, the energy dissipation mechanism of the ultraviolet absorber, and the physical barrier effect of zirconium phosphate constitute a multi-level protection system. This system not only converts harmful ultraviolet light into effective visible light but also delays the photothermal aging of the material through both chemical and physical mechanisms. Detailed Implementation
[0019] Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0020] In the following specific implementation, Europium oxide: Product number S24339, sourced from Shanghai Yuanye Biotechnology Co., Ltd.; Lanthanum nitrate hexahydrate: Product No. 1182333, sourced from Shanghai Haohong Biomedical Technology Co., Ltd.; Ethylene-vinyl acetate copolymer (EVA) resin: Product number P101486, sourced from Aladdin Biochemical Technology Co., Ltd. 2,5-Dimethyl-2,5-bis(tert-butylperoxide)hexane: Product No. T110273, sourced from Aladdin Biochemical Technology Co., Ltd.; Triallyl isocyanurate: Product code S32045, sourced from Shanghai Yuanye Biotechnology Co., Ltd.; Benzophenone: Product number S24186, sourced from Shanghai Yuanye Biotechnology Co., Ltd.; Vinyltris(2-methoxyethoxy)silane: Product No. A067534, sourced from Zhengzhou Huiju Chemical Co., Ltd.; Maleic anhydride: Product number 20191123, sourced from Jinan Jinhao Chemical Co., Ltd.; Benzoyl peroxide: Product number C0794510323, sourced from Nanjing Chemical Reagent Co., Ltd.; Nitric acid, zirconium phosphate, toluene, methanol, acetone, isooctylamine, and anhydrous ethanol were all of analytical grade.
[0021] Example 1: A light transfer film for photovoltaic modules and its preparation method, comprising the following steps: Step 1: Add 3 mL of nitric acid to 100 mL of deionized water and stir until homogeneous. Add 0.006 g of europium oxide and stir until completely dissolved to form a transparent solution. Add 0.5 g of lanthanum nitrate hexahydrate and continue stirring until homogeneous. In a 55°C water bath, slowly add ammonia water dropwise with stirring until a white precipitate forms. Adjust the pH of the solution to 8.9 and continue stirring for 0.5 h. Filter the solution using a vacuum pump and dry it in an oven at 145°C to obtain a mixture. Transfer the mixture to a ceramic boat and place it in a muffle furnace. Heat the mixture to 750°C at a heating rate of 2°C / min and calcine for 1 h to obtain the composite light conversion powder. Step 2: Dilute 1 mL of vinyltris(2-methoxyethoxy)silane with 19 mL of 95% ethanol aqueous solution to obtain vinyltris(2-methoxyethoxy)silane diluted solution; spray 20 mL of vinyltris(2-methoxyethoxy)silane diluted solution evenly on the surface of 10 g of composite light conversion powder to obtain pretreated composite light conversion powder; Step 3: By mass percentage, 95.1% of modified ethylene-vinyl acetate copolymer resin is placed in a mixer, along with 0.1% pretreated composite light conversion powder, 2% 2,5-dimethyl-2,5-bis(tert-butylperoxide)hexane, 0.2% triallyl isocyanurate, 0.1% benzophenone, and 2.5% modified zirconium phosphate. The mixture is then fed into a casting machine and subjected to plasticizing extrusion, stretching, traction, and winding at 80°C to produce a light transfer film for photovoltaic modules. The preparation steps of the modified ethylene-vinyl acetate copolymer resin are as follows: S1: A 50mL Schlank flask after vacuum drying was placed in a magnetic flask and connected to a double row of tubes. After vacuuming, baking, and nitrogen purging, 1g of ethylene-vinyl acetate copolymer resin, 5.34g of maleic anhydride, 0.55g of benzoyl peroxide and 50mL of toluene were added under a nitrogen atmosphere. The mixture was heated to 55℃ and stirred for 15min to completely dissolve the raw materials. The temperature was then slowly increased to 70℃ and reacted for 7h. After the reaction was completed, the mixture was dropped into ice-cold methanol and stirred. An orange-yellow flocculent precipitate was formed. After filtration, washing with acetone and vacuum drying, the grafted ethylene-vinyl acetate copolymer resin was obtained. S2: 1g of grafted ethylene-vinyl acetate copolymer resin was dried in a vacuum drying oven at 70℃ for 23h to remove the unreacted maleic anhydride monomer on the surface by sublimation. 50mL of toluene was added and heated under reflux to dissolve it completely. The insoluble matter was removed by filtration. The filtrate was then added dropwise to acetone and stirred to precipitate flocculent precipitate. The precipitate was filtered and dried to obtain the modified ethylene-vinyl acetate copolymer resin. The preparation steps of the modified zirconium phosphate are as follows: 2.5g zirconium phosphate, 5g isooctylamine and 7.5g anhydrous ethanol were added to a wide-mouth bottle, sealed and reacted on a magnetic stirrer for 9h to obtain a mixture. The mixture was transferred to a petri dish and allowed to stand for layering. After removing the supernatant, it was dried in a vacuum oven at 45℃ for 47h to obtain modified zirconium phosphate.
[0022] Example 2: A light transfer film for photovoltaic modules and its preparation method, comprising the following steps: Step 1: Add 6 mL of nitric acid to 200 mL of deionized water and stir until homogeneous. Add 0.012 g of europium oxide and stir until completely dissolved to form a transparent solution. Add 1 g of lanthanum nitrate hexahydrate and continue stirring until homogeneous. In a 60 °C water bath, slowly add ammonia water dropwise while stirring until a white precipitate forms. Adjust the pH of the solution to 9.0 and continue stirring for 1 hour. Filter the solution using a vacuum pump and dry it in an oven at 150 °C to obtain a mixture. Transfer the mixture to a ceramic boat and place it in a muffle furnace. Heat the mixture to 800 °C at a heating rate of 2 °C / min and calcine for 2 hours to obtain the composite light conversion powder. Step 2: Dilute 1 mL of vinyltris(2-methoxyethoxy)silane with 19 mL of 95% ethanol aqueous solution to obtain vinyltris(2-methoxyethoxy)silane diluted solution; spray 20 mL of vinyltris(2-methoxyethoxy)silane diluted solution evenly on the surface of 10 g of composite light conversion powder to obtain pretreated composite light conversion powder; Step 3: By mass percentage, 93.4% of the modified ethylene-vinyl acetate copolymer resin is placed in a mixer, along with 0.15% of pretreated composite light conversion powder, 3% of 2,5-dimethyl-2,5-bis(tert-butylperoxide)hexane, 0.3% of triallyl isocyanurate, 0.15% of benzophenone, and 3% of modified zirconium phosphate. The mixture is then fed into a casting machine and subjected to plasticizing extrusion, stretching, traction, and winding at 85°C to produce a light transfer film for photovoltaic modules. The preparation steps of the modified ethylene-vinyl acetate copolymer resin are as follows: S1: A 50mL Schlank flask after vacuum drying was placed in a magnetic flask and connected to a double row of tubes. After vacuuming, baking, and nitrogen purging, 2g of ethylene-vinyl acetate copolymer resin, 10.68g of maleic anhydride, 1.1g of benzoyl peroxide, and 100mL of toluene were added under a nitrogen atmosphere. The mixture was heated to 60℃ and stirred for 20min to completely dissolve the raw materials. The temperature was then slowly increased to 75℃ and reacted for 7.5h. After the reaction was completed, the mixture was dropped into ice-cold methanol and stirred. An orange-yellow flocculent precipitate was formed. After filtration, washing with acetone, and vacuum drying, the grafted ethylene-vinyl acetate copolymer resin was obtained. S2: 2g of grafted ethylene-vinyl acetate copolymer resin was dried in a vacuum drying oven at 75℃ for 24h to remove the unreacted maleic anhydride monomer on the surface by sublimation. 100mL of toluene was added and heated under reflux to dissolve it completely. The insoluble matter was removed by filtration. The filtrate was then added to acetone to precipitate flocculent precipitate. The precipitate was filtered and dried to obtain the modified ethylene-vinyl acetate copolymer resin. The preparation steps of the modified zirconium phosphate are as follows: Add 5g zirconium phosphate, 10g isooctylamine and 15g anhydrous ethanol to a wide-mouth bottle, seal it and react it on a magnetic stirrer for 10h to obtain a mixture. Transfer the mixture to a petri dish and let it stand to separate into layers. After removing the supernatant, dry it in a vacuum oven at 50℃ for 48h to obtain modified zirconium phosphate.
[0023] Example 3: A light transfer film for photovoltaic modules and its preparation method, comprising the following steps: Step 1: Add 9 mL of nitric acid to 300 mL of deionized water and stir until homogeneous. Add 0.018 g of europium oxide and stir until completely dissolved to form a transparent solution. Add 1.5 g of lanthanum nitrate hexahydrate and continue stirring until homogeneous. In a 65°C water bath, slowly add ammonia water dropwise with stirring until a white precipitate forms. Adjust the pH of the solution to 9.1 and continue stirring for 1.5 h. Filter the solution using a vacuum pump and dry it in an oven at 155°C to obtain a mixture. Transfer the mixture to a ceramic boat and place it in a muffle furnace. Heat the mixture to 850°C at a heating rate of 2°C / min and calcine for 3 h to obtain the composite light conversion powder. Step 2: Dilute 1 mL of vinyltris(2-methoxyethoxy)silane with 19 mL of 95% ethanol aqueous solution to obtain vinyltris(2-methoxyethoxy)silane diluted solution; spray 20 mL of vinyltris(2-methoxyethoxy)silane diluted solution evenly on the surface of 10 g of composite light conversion powder to obtain pretreated composite light conversion powder; Step 3: By mass percentage, 91.7% of the modified ethylene-vinyl acetate copolymer resin is placed in a mixer, along with 0.2% of pretreated composite light conversion powder, 4% of 2,5-dimethyl-2,5-bis(tert-butylperoxide)hexane, 0.4% of triallyl isocyanurate, 0.2% of benzophenone, and 3.5% of modified zirconium phosphate. The mixture is then fed into a casting machine and subjected to plasticizing extrusion, stretching, traction, and winding at 90°C to produce a light transfer film for photovoltaic modules. The preparation steps of the modified ethylene-vinyl acetate copolymer resin are as follows: S1: A 50mL Schlank flask after vacuum drying was placed in a magnetic flask and connected to a double row of tubes. After vacuuming, baking, and nitrogen purging 5 times, 3g of ethylene-vinyl acetate copolymer resin, 16.02g of maleic anhydride, 1.65g of benzoyl peroxide and 150mL of toluene were added under a nitrogen atmosphere. The mixture was heated to 65℃ and stirred for 25min to completely dissolve the raw materials. The temperature was then slowly increased to 80℃ and reacted for 8h. After the reaction was completed, the mixture was dropped into ice-cold methanol and stirred. An orange-yellow flocculent precipitate was formed. After filtration, washing with acetone and vacuum drying, the grafted ethylene-vinyl acetate copolymer resin was obtained. S2: 3g of grafted ethylene-vinyl acetate copolymer resin was dried in a vacuum drying oven at 80℃ for 25h to remove the unreacted maleic anhydride monomer on the surface by sublimation. 150mL of toluene was added and heated under reflux to dissolve it completely. The insoluble matter was removed by filtration. The filtrate was then added to acetone to precipitate flocculent precipitate. The precipitate was filtered and dried to obtain the modified ethylene-vinyl acetate copolymer resin. The preparation steps of the modified zirconium phosphate are as follows: 7.5g of zirconium phosphate, 15g of isooctylamine and 22.5g of anhydrous ethanol were added to a wide-mouth bottle, sealed and reacted on a magnetic stirrer for 11h to obtain a mixture. The mixture was then transferred to a petri dish and allowed to stand for layering. After removing the supernatant, the mixture was dried in a vacuum oven at 55℃ for 49h to obtain modified zirconium phosphate.
[0024] Comparative Example 1: Compared with Example 3, the added zirconium phosphate was not modified; Step 1: Add 9 mL of nitric acid to 300 mL of deionized water and stir until homogeneous. Add 0.018 g of europium oxide and stir until completely dissolved to form a transparent solution. Add 1.5 g of lanthanum nitrate hexahydrate and continue stirring until homogeneous. In a 65°C water bath, slowly add ammonia water dropwise with stirring until a white precipitate forms. Adjust the pH of the solution to 9.1 and continue stirring for 1.5 h. Filter the solution using a vacuum pump and dry it in an oven at 155°C to obtain a mixture. Transfer the mixture to a ceramic boat and place it in a muffle furnace. Heat the mixture to 850°C at a heating rate of 2°C / min and calcine for 3 h to obtain the composite light conversion powder. Step 2: Dilute 1 mL of vinyltris(2-methoxyethoxy)silane with 19 mL of 95% ethanol aqueous solution to obtain vinyltris(2-methoxyethoxy)silane diluted solution; spray 20 mL of vinyltris(2-methoxyethoxy)silane diluted solution evenly on the surface of 10 g of composite light conversion powder to obtain pretreated composite light conversion powder; Step 3: By mass percentage, 91.7% of the modified ethylene-vinyl acetate copolymer resin is placed in a mixer, along with 0.2% of pretreated composite light conversion powder, 4% of 2,5-dimethyl-2,5-bis(tert-butylperoxide)hexane, 0.4% of triallyl isocyanurate, 0.2% of benzophenone, and 3.5% of zirconium phosphate. The mixture is then fed into a casting machine and subjected to plasticizing extrusion, stretching, traction, and winding at 90°C to produce a light transfer film for photovoltaic modules. The preparation steps of the modified ethylene-vinyl acetate copolymer resin are as follows: S1: A 50mL Schlank flask after vacuum drying was placed in a magnetic flask and connected to a double row of tubes. After vacuuming, baking, and nitrogen purging 5 times, 3g of ethylene-vinyl acetate copolymer resin, 16.02g of maleic anhydride, 1.65g of benzoyl peroxide and 150mL of toluene were added under a nitrogen atmosphere. The mixture was heated to 65℃ and stirred for 25min to completely dissolve the raw materials. The temperature was then slowly increased to 80℃ and reacted for 8h. After the reaction was completed, the mixture was dropped into ice-cold methanol and stirred. An orange-yellow flocculent precipitate was formed. After filtration, washing with acetone and vacuum drying, the grafted ethylene-vinyl acetate copolymer resin was obtained. S2: 3g of grafted ethylene-vinyl acetate copolymer resin was dried in a vacuum drying oven at 80℃ for 25h to remove the unreacted maleic anhydride monomer on the surface by sublimation. 150mL of toluene was added and heated under reflux to completely dissolve the resin. The insoluble matter was removed by filtration. The filtrate was then added dropwise to acetone to precipitate a flocculent precipitate. The precipitate was then filtered and dried to obtain the modified ethylene-vinyl acetate copolymer resin.
[0025] Comparative Example 2: Compared with Example 3, the ethylene-vinyl acetate copolymer resin used was not modified; Step 1: Add 9 mL of nitric acid to 300 mL of deionized water and stir until homogeneous. Add 0.018 g of europium oxide and stir until completely dissolved to form a transparent solution. Add 1.5 g of lanthanum nitrate hexahydrate and continue stirring until homogeneous. In a 65°C water bath, slowly add ammonia water dropwise with stirring until a white precipitate forms. Adjust the pH of the solution to 9.1 and continue stirring for 1.5 h. Filter the solution using a vacuum pump and dry it in an oven at 155°C to obtain a mixture. Transfer the mixture to a ceramic boat and place it in a muffle furnace. Heat the mixture to 850°C at a heating rate of 2°C / min and calcine for 3 h to obtain the composite light conversion powder. Step 2: Dilute 1 mL of vinyltris(2-methoxyethoxy)silane with 19 mL of 95% ethanol aqueous solution to obtain vinyltris(2-methoxyethoxy)silane diluted solution; spray 20 mL of vinyltris(2-methoxyethoxy)silane diluted solution evenly on the surface of 10 g of composite light conversion powder to obtain pretreated composite light conversion powder; Step 3: By mass percentage, 91.7% of ethylene-vinyl acetate copolymer resin is placed in a mixer, along with 0.2% pretreated composite light conversion powder, 4% 2,5-dimethyl-2,5-bis(tert-butylperoxide)hexane, 0.4% triallyl isocyanurate, 0.2% benzophenone, and 3.5% modified zirconium phosphate. The mixture is then fed into a casting machine and subjected to plasticizing extrusion, stretching, traction, and winding at 90°C to produce a light transfer film for photovoltaic modules. The preparation steps of the modified zirconium phosphate are as follows: 7.5g of zirconium phosphate, 15g of isooctylamine and 22.5g of anhydrous ethanol were added to a wide-mouth bottle, sealed and reacted on a magnetic stirrer for 11h to obtain a mixture. The mixture was then transferred to a petri dish and allowed to stand for layering. After removing the supernatant, the mixture was dried in a vacuum oven at 55℃ for 49h to obtain modified zirconium phosphate.
[0026] Comparative Example 3: Compared with Example 3, europium oxide was not added in step 1; Step 1: Add 9 mL of nitric acid to 300 mL of deionized water and stir until homogeneous. Add 1.5 g of lanthanum nitrate hexahydrate and continue stirring until it dissolves evenly. In a 65 °C water bath, slowly add ammonia water dropwise while stirring until a white precipitate forms. Adjust the pH of the solution to 9.1 and continue stirring for 1.5 h. Filter the solution using a vacuum pump and dry it in an oven at 155 °C to obtain a mixture. Transfer the mixture to a ceramic boat and place it in a muffle furnace. Heat the mixture to 850 °C at a heating rate of 2 °C / min and calcine for 3 h to obtain the light conversion powder. Step 2: Dilute 1 mL of vinyltris(2-methoxyethoxy)silane with 19 mL of 95% ethanol aqueous solution to obtain vinyltris(2-methoxyethoxy)silane diluted solution; spray 20 mL of vinyltris(2-methoxyethoxy)silane diluted solution evenly on the surface of 10 g of composite light conversion powder to obtain pretreated light conversion powder; Step 3: By mass percentage, 91.7% of modified ethylene-vinyl acetate copolymer resin is placed in a mixer, along with 0.2% light conversion powder, 4% 2,5-dimethyl-2,5-bis(tert-butylperoxide)hexane, 0.4% triallyl isocyanurate, 0.2% benzophenone, and 3.5% modified zirconium phosphate. The mixture is then fed into a casting machine and subjected to plasticizing extrusion, stretching, traction, and winding at 90°C to produce a light transfer film for photovoltaic modules. The preparation steps of the modified ethylene-vinyl acetate copolymer resin are as follows: S1: A 50mL Schlank flask after vacuum drying was placed in a magnetic flask and connected to a double row of tubes. After vacuuming, baking, and nitrogen purging 5 times, 3g of ethylene-vinyl acetate copolymer resin, 16.02g of maleic anhydride, 1.65g of benzoyl peroxide and 150mL of toluene were added under a nitrogen atmosphere. The mixture was heated to 65℃ and stirred for 25min to completely dissolve the raw materials. The temperature was then slowly increased to 80℃ and reacted for 8h. After the reaction was completed, the mixture was dropped into ice-cold methanol and stirred. An orange-yellow flocculent precipitate was formed. After filtration, washing with acetone and vacuum drying, the grafted ethylene-vinyl acetate copolymer resin was obtained. S2: 3g of grafted ethylene-vinyl acetate copolymer resin was dried in a vacuum drying oven at 80℃ for 25h to remove the unreacted maleic anhydride monomer on the surface by sublimation. 150mL of toluene was added and heated under reflux to dissolve it completely. The insoluble matter was removed by filtration. The filtrate was then added to acetone to precipitate flocculent precipitate. The precipitate was filtered and dried to obtain the modified ethylene-vinyl acetate copolymer resin. The preparation steps of the modified zirconium phosphate are as follows: 7.5g of zirconium phosphate, 15g of isooctylamine and 22.5g of anhydrous ethanol were added to a wide-mouth bottle, sealed and reacted on a magnetic stirrer for 11h to obtain a mixture. The mixture was then transferred to a petri dish and allowed to stand for layering. After removing the supernatant, the mixture was dried in a vacuum oven at 55℃ for 49h to obtain modified zirconium phosphate.
[0027] Experiment: Photovoltaic modules prepared in Examples 1-3 and Comparative Examples 1-3 were used to make photovoltaic module samples for testing using phototransfer films, and their performance was tested. Preparation of photovoltaic module samples: The modules are composed of an upper glass layer, an upper light transfer film, a solar cell, a lower light transfer film, and a lower glass layer in sequence. The upper and lower light transfer films are both light transfer films prepared using this invention. The upper and lower glass layers are both white ceramic-coated backsheet glass from Changzhou Yamatong Co., Ltd. The solar cells are 210-size heterojunction solar cells (model JGYC-210-20BB_CN, from Gansu Jingang Photovoltaic Co., Ltd.). Finally, a 110-size module is made. Yellowing value test: The yellowing value of the sample (50 mm thick 0.5 mm phototransfer film) was tested according to the provisions of GB / T 3979-2008 and GB / T 7921-2008 under ultraviolet radiation of 120 kWh / m. 2 The yellowing value afterward; Transmittance test: Using GB / T 2410-2008 as the reference standard, take a light transfer film with a diameter of 50mm and a thickness of 0.5mm, and calculate the average transmittance in the wavelength ranges of 290~380nm and 380~1100nm; Photovoltaic module power testing: Using IEC 61215-2021 as the reference standard, the initial power and ultraviolet radiation (UV) of the photovoltaic modules were tested at 120 kWh / m². 2 The power was then tested, and the attenuation rate was calculated based on the two sets of data. All experimental results are shown in Table 1.
[0028] Table 1
[0029] As shown in Table 1, Examples 1-3 exhibited lower UV aging yellowing values and higher transmittance in the 280-380 nm UV band, indicating that the nano-barrier effect of modified zirconium phosphate and the synergistic effect of the UV absorber effectively suppressed the photo-oxidative aging of the film. Simultaneously, their high transmittance in the 380-1100 nm visible-near-infrared band confirmed the high dispersion and interfacial compatibility of the functional filler in the modified EVA matrix, ensuring effective photon transmission. The photovoltaic modules of Examples 1-3, after undergoing a 120 kWh / m² exposure, showed improved performance. 2 The power decay rate after ultraviolet irradiation was significantly lower than that of the comparative example. This result proves that the multi-level synergistic system of "light conversion-blocking-stabilization" constructed by interface chemical modification not only efficiently converts ultraviolet light into usable visible light to improve the initial power, but also ensures the long-term power stability of the component under ultraviolet irradiation conditions by inhibiting photothermal aging and interface degradation, thus achieving simultaneous optimization of photoelectric conversion efficiency and durability.
[0030] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.
Claims
1. A method for preparing a light transfer film for photovoltaic modules, characterized in that: Includes the following steps: Step 1: Add nitric acid and europium oxide to deionized water and stir. Add lanthanum nitrate hexahydrate, stir and add ammonia dropwise in a water bath to adjust the pH of the solution. Continue stirring, filter, and dry to obtain a mixture. Heat the mixture and calcine to obtain composite light conversion powder. Step 2: Dilute vinyltris(2-methoxyethoxy)silane with an aqueous ethanol solution and spray it evenly onto the surface of the composite light conversion powder to obtain pretreated composite light conversion powder; Step 3: Put the modified ethylene-vinyl acetate copolymer resin into a mixer, add pretreated composite light conversion powder, crosslinking agent, co-crosslinking agent, ultraviolet light absorber and modified zirconium phosphate, mix evenly, put into a casting machine, and make a light transfer film for photovoltaic modules through plasticizing extrusion, stretching, traction and winding.
2. The method for preparing a light transfer film for photovoltaic modules according to claim 1, characterized in that: In step 1, the deionized water, nitric acid, europium oxide, and lanthanum nitrate hexahydrate are mixed in a mass ratio of 100:3:0.006:0.5; in step 2, vinyltris(2-methoxyethoxy)silane is diluted with an aqueous ethanol solution in a volume ratio of 1:19, and the mass ratio of the composite light conversion powder to the vinyltris(2-methoxyethoxy)silane dilution is 1:
2.
3. The method for preparing a light transfer film for photovoltaic modules according to claim 1, characterized in that: The composition of the photovoltaic module light transfer film described in step 3, by mass percentage, includes 0.1%~0.2% pretreated composite light conversion powder, 2%~4% crosslinking agent, 0.2%~0.4% co-crosslinking agent, 0.1%~0.2% ultraviolet light absorber, 2.5%~3.5% modified zirconium phosphate, and the balance is modified ethylene-vinyl acetate copolymer resin.
4. The method for preparing a light transfer film for photovoltaic modules according to claim 1, characterized in that: The crosslinking agent is 2,5-dimethyl-2,5-bis(tert-butylperoxide)hexane, the co-crosslinking agent is triallyl isocyanurate, and the ultraviolet absorber is benzophenone.
5. The method for preparing a light transfer film for photovoltaic modules according to claim 1, characterized in that: In step 1, the water bath temperature is 55~65℃, the pH value is adjusted to 8.9~9.1, stirring is continued for 0.5~1.5h, the drying temperature is 145~155℃, the heating and calcining temperature is 750~850℃, and the time is 1~3h; in step 3, the plasticizing extrusion temperature is 80~90℃.
6. The method for preparing a light transfer film for photovoltaic modules according to claim 1, characterized in that: The preparation steps of the modified ethylene-vinyl acetate copolymer resin are as follows: S1: Under a nitrogen atmosphere, ethylene-vinyl acetate copolymer resin, maleic anhydride, benzoyl peroxide and toluene are mixed, heated to 55~65℃, stirred for 15~25min, heated to 70~80℃ and reacted for 7~8h, then dropped into ice-cold methanol and stirred, filtered, washed with acetone and dried under vacuum to obtain the grafted ethylene-vinyl acetate copolymer resin. S2: Dry the grafted ethylene-vinyl acetate copolymer resin at 70~80℃ for 23~25h, add toluene, heat under reflux, filter, add the filtrate dropwise into acetone and stir, filter and dry to obtain the modified ethylene-vinyl acetate copolymer resin.
7. The method for preparing a light transfer film for photovoltaic modules according to claim 6, characterized in that: The mass ratio of the ethylene-vinyl acetate copolymer resin, maleic anhydride, benzoyl peroxide, and toluene in S1 is 1:5.34:0.55:50; the mass ratio of the grafted ethylene-vinyl acetate copolymer resin to toluene in S2 is 1:
50.
8. The method for preparing a light transfer film for photovoltaic modules according to claim 1, characterized in that: The preparation steps of the modified zirconium phosphate are as follows: Zirconium phosphate, isooctylamine, and anhydrous ethanol were mixed, sealed, and reacted on a magnetic stirrer for 9-11 hours to obtain a mixture. The mixture was then transferred to a petri dish and allowed to stand for separation. After removing the supernatant, the mixture was dried in a vacuum oven at 45-55°C for 47-49 hours to obtain modified zirconium phosphate.
9. The method for preparing a light transfer film for photovoltaic modules according to claim 8, characterized in that: The zirconium phosphate, isooctylamine, and anhydrous ethanol are mixed in a mass ratio of 0.5:1:1.
5.
10. A light transfer film for photovoltaic modules is prepared by the preparation method according to any one of claims 1-9.