UV-aging-resistant light conversion agent, preparation method thereof, light conversion adhesive film and photovoltaic module

Abstract

The invention relates to the technical field of photovoltaic materials, in particular to a UV-aging-resistant light conversion agent, a preparation method thereof, a light conversion adhesive film and a photovoltaic module. The UV aging-resistant light conversion agent comprises a copolymer which is prepared from a benzotriazole compound containing unsaturated bonds and methyl methacrylate through anionic polymerization. The light conversion agent provided by the invention can improve the dispersion uniformity of benzotriazole compounds, reduce fluorescence quenching, promote fluorescence emission through a copolymerization structure, and improve the fluorescence quantum efficiency; meanwhile, the methyl methacrylate chain segment can coat the benzotriazole compound to form a physical barrier, so that the UV aging resistance of the light conversion agent is improved; in addition, the tail end of the light conversion agent is an unsaturated bond, and the light conversion agent can participate in the reaction and is modified to the EVA resin, so that the migration problem is effectively inhibited.

Description

Technical Field

[0001] This invention relates to the field of photovoltaic materials technology, and in particular to a UV-resistant light transfer agent, its preparation method, light transfer film, and photovoltaic module. Background Technology

[0002] Light transfer materials (LTCs) are functional materials that can absorb light of a specific wavelength and convert it into light of other wavelengths. LTCs are widely used in the photovoltaic field to improve the efficiency of light energy utilization. Current LTCs mainly include organic fluorescent pigments, rare-earth organic complexes, rare-earth inorganic compounds, and quantum dots. However, these materials still face several technical bottlenecks in practical applications: Firstly, under UV irradiation, LTCs undergo photodegradation, leading to molecular structure destruction. This photo-induced degradation significantly reduces light transfer efficiency, thus affecting module power. Although adding UV blockers can appropriately protect LTCs, it results in a loss of some UV light utilization. Secondly, in HJT and other battery modules, some LTC material in the front-side LTC film migrates from the gaps between cells to the back-side LTC film, reducing the amount of LTC material in the front-side film and causing a decrease in the front-side LTC efficiency.

[0003] In view of this, the present invention is hereby proposed. Summary of the Invention

[0004] One objective of this invention is to provide a UV-resistant light transfer agent to solve the technical problems of reduced light transfer efficiency caused by structural damage to existing light transfer materials under UV irradiation conditions.

[0005] Another object of the present invention is to provide a method for preparing a UV-resistant phototransfer agent.

[0006] Another object of the present invention is to provide a light transfer film comprising the above-mentioned UV-resistant light transfer agent.

[0007] Another object of the present invention is to provide a photovoltaic module comprising the above-mentioned phototransfer film.

[0008] To achieve the above-mentioned objectives of the present invention, a first aspect of the present invention provides a UV-resistant phototransfer agent, comprising a copolymer obtained by anionic polymerization of a benzotriazole compound containing unsaturated bonds and methyl methacrylate; The benzotriazole compounds containing unsaturated bonds are selected from at least one of the following formulas I to II: , ; In this context, R in Equations I and II are each independently selected from... , .

[0009] In a specific embodiment of the present invention, the mass ratio of the benzotriazole compound containing unsaturated bonds to the methyl methacrylate is (5-20):100.

[0010] In a specific embodiment of the present invention, the number-average molecular weight of the copolymer is 8000 to 15000.

[0011] In a specific embodiment of the present invention, the molecular weight distribution width of the copolymer is 1.2 to 1.5.

[0012] The second aspect of the present invention provides a method for preparing the UV-resistant phototransfer agent of the first aspect of the present invention, comprising the following steps: anionic polymerization reaction of a benzotriazole compound containing unsaturated bonds and methyl methacrylate in a solvent under the action of a catalyst and an initiator; after the reaction is completed, the solid phase is collected and washed to obtain the UV-resistant phototransfer agent.

[0013] In a specific embodiment of the present invention, the catalyst is 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU). Further, the amount of the catalyst used is 0.05% to 2% of the mass of the methyl methacrylate.

[0014] In a specific embodiment of the present invention, the initiator is ethylene glycol. Further, the amount of the initiator used is 0.05% to 0.1% of the mass of the methyl methacrylate.

[0015] In a specific embodiment of the present invention, the solvent includes xylene. Further, the amount of the solvent used is 0.5 to 2 times the mass of the methyl methacrylate.

[0016] In a specific embodiment of the present invention, the reaction temperature in the anionic polymerization reaction is 50–70°C and the reaction time is 4–6 h.

[0017] A third aspect of the present invention provides a light transfer film, comprising a film body and a UV-resistant light transfer agent of the first aspect of the present invention dispersed within the film body.

[0018] In a specific embodiment of the present invention, the mass fraction of the UV-resistant phototransfer agent in the phototransfer film is 0.4% to 10%.

[0019] A fourth aspect of the present invention provides a photovoltaic module, including the light transfer film provided in the third aspect of the present invention.

[0020] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) The phototransfer agent of the present invention comprises a copolymer obtained by copolymerizing benzotriazole compounds containing unsaturated bonds with methyl methacrylate. The benzotriazole compounds in the copolymer are distributed on the polymer chain of methyl methacrylate, which can avoid the close packing of the benzotriazole compounds themselves, improve the dispersion uniformity, reduce fluorescence quenching, and promote fluorescence emission through the copolymer structure, thereby improving the fluorescence quantum efficiency. Furthermore, the formation of chemical bonds in the copolymer structure enhances the stability of the benzotriazole compounds, and the methyl methacrylate segments will coat the benzotriazole compounds to form a physical barrier, thereby improving the UV aging resistance of the phototransfer agent.

[0021] (2) The light transfer agent of the present invention comprises a copolymer obtained by copolymerizing benzotriazole compounds containing unsaturated bonds with methyl methacrylate. The copolymer ends with unsaturated bonds, which can participate in the reaction during the lamination process of photovoltaic module preparation and modify EVA resin to effectively suppress its migration problem.

[0022] (3) The light transfer film of the present invention contains the above-mentioned light transfer agent, which can not only ensure the uniformity of the dispersion of the light transfer agent, but also improve the fluorescence quantum efficiency of the light transfer film and enhance the power of the HJT module; in addition, the light transfer agent has UV aging resistance and can reduce the power decay rate of the HJT module in actual use. Attached Figure Description

[0023] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0024] Figure 1 The initial fluorescence on the back side of the component prepared using the phototransfer film of Example 1 of the present invention is shown under ultraviolet light irradiation. Figure 2 The fluorescence on the back of the component prepared by the phototransfer film of Example 1 of the present invention is observed after heating in an oven at 150°C for 96 hours and then irradiating with ultraviolet light. Figure 3 The fluorescence on the back of the module prepared using the phototransfer film of Comparative Example 3 was observed after heating in an oven at 150°C for 96 hours and then irradiated with ultraviolet light. Detailed Implementation

[0025] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings and specific embodiments. However, those skilled in the art will understand that the embodiments described below are some embodiments of the present invention, but not all embodiments, and are only used to illustrate the present invention, and should not be regarded as limiting the scope of the present invention. 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. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall be followed. Where the manufacturers of reagents or instruments are not specified, they are all conventional products that can be purchased commercially.

[0026] The first aspect of the present invention provides a UV-resistant phototransfer agent, comprising a copolymer obtained by anionic polymerization of a benzotriazole compound containing unsaturated bonds and methyl methacrylate; Benzotriazole compounds containing unsaturated bonds are selected from at least one of the following formulas I to II: , ; In these equations, R is independently selected from each of the following formulas: I and II. , .

[0027] In different embodiments, the structures of benzotriazole compounds containing unsaturated bonds can be as follows: , , , .

[0028] The method for preparing the benzotriazole compounds containing unsaturated bonds of the present invention can be referred to the method described in Chinese patent application CN117720474A, but is not limited thereto. The unsaturated bonds in the benzotriazole compounds of the present invention can undergo anionic polymerization with the double bonds in methyl methacrylate under the initiation of an initiator to obtain a copolymer. The benzotriazole compounds in the copolymer are distributed on the polymer chains of methyl methacrylate, avoiding the close packing of the benzotriazole compounds themselves, which not only improves the dispersion uniformity but also reduces fluorescence quenching; furthermore, the formation of chemical bonds in the copolymer structure enhances the stability of the benzotriazole compounds. Simultaneously, the methyl methacrylate segments coat the benzotriazole compounds, forming a physical barrier and improving the UV aging resistance of the phototransfer agent. Furthermore, the polymerized methyl methacrylate has high light transmittance and good compatibility with film substrates such as EVA resin.

[0029] In a specific embodiment of the present invention, the mass ratio of the benzotriazole compound containing unsaturated bonds to methyl methacrylate is (5-20):100. In different embodiments, the mass ratio of the benzotriazole compound containing unsaturated bonds to methyl methacrylate can be 5:100, 8:100, 10:100, 12:100, 15:100, 18:100, 20:100, or any combination thereof. Controlling the ratio within the above range helps to balance the distribution of the benzotriazole compound in the copolymer chain and the coating and protection of the benzotriazole compound by the methyl methacrylate segments. When the amount of benzotriazole compounds containing unsaturated bonds is too low, the content of benzotriazole compounds in the prepared light transfer agent is low, resulting in low fluorescence efficiency. When the amount of benzotriazole compounds containing unsaturated bonds is too high, it is not conducive to the distribution of benzotriazole compounds in the copolymer chain and the full coating of benzotriazole compounds by methyl methacrylate.

[0030] In a specific embodiment of the present invention, the number average molecular weight of the copolymer is 8,000 to 15,000. In different embodiments, the number average molecular weight of the copolymer may be 8,000, 9,000, 10,000, 11,000, 12,000, 13,000, 14,000, 15,000, or any combination thereof.

[0031] In a specific embodiment of the present invention, the molecular weight distribution width of the copolymer is 1.2 to 1.5. In different embodiments, the molecular weight distribution width of the copolymer can be a range of 1.2, 1.3, 1.4, 1.5, or any combination thereof.

[0032] The second aspect of the present invention provides a method for preparing a UV-resistant phototransfer agent according to the first aspect of the present invention, comprising the following steps: anionic polymerization of a benzotriazole compound containing unsaturated bonds and methyl methacrylate in a solvent under the action of a catalyst and an initiator; after the reaction is completed, the solid phase is collected and washed to obtain a UV-resistant phototransfer agent.

[0033] This invention prepares UV-resistant phototransfer agents through anionic polymerization. On the one hand, this method is beneficial for controlling the molecular weight and results in a narrow molecular weight distribution of the copolymer. On the other hand, after the copolymerization reaction, the terminal unsaturated bonds can be retained, which is beneficial for modifying the phototransfer agent onto the EVA resin through covalent bonds during the assembly and lamination process of the components, effectively inhibiting the migration of the phototransfer agent.

[0034] In a specific embodiment of the present invention, the catalyst is 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU). Further, the amount of catalyst used is 0.05% to 2% of the mass of methyl methacrylate, such as 0.05%, 0.1%, 0.5%, 1%, 1.5%, 2%, or any combination thereof.

[0035] In a specific embodiment of the present invention, the initiator is ethylene glycol. Further, the amount of initiator is 0.05% to 0.1% of the mass of methyl methacrylate, such as 0.05%, 0.06%, 0.07%, 0.08%, 0.09%, 0.1%, or any combination thereof. Using the above-mentioned amount of initiator ensures that the copolymer obtained by anionic polymerization has a suitable molecular weight.

[0036] In a specific embodiment of the present invention, the solvent includes xylene. Further, the amount of solvent used is 0.5 to 2 times the mass of methyl methacrylate, such as 0.5 times, 0.8 times, 1 time, 1.2 times, 1.5 times, 1.8 times, 2 times, or any combination thereof.

[0037] In a specific embodiment of the present invention, the reaction temperature in the anionic polymerization reaction is 50–70°C, and the reaction time is 4–6 h.

[0038] In different embodiments, the reaction temperature can be a range of 50°C, 55°C, 60°C, 65°C, 70°C or any combination thereof; the reaction time can be a range of 4h, 4.5h, 5h, 5.5h, 6h or any combination thereof. The reaction time can be conventionally adjusted according to the number average molecular weight of the copolymer obtained by the anionic polymerization reaction to obtain a copolymer with a molecular weight that meets the requirements.

[0039] A third aspect of the present invention provides a light transfer film, comprising a film body and a UV-resistant light transfer agent of the first aspect of the present invention dispersed within the film body.

[0040] The light transfer agent of the present invention comprises a copolymer obtained by copolymerizing benzotriazole compounds containing unsaturated bonds with methyl methacrylate, which has excellent UV aging resistance and anti-migration properties, and helps to improve the power of the module and reduce the power decay rate of the module during actual use.

[0041] In a specific embodiment of the present invention, the mass fraction of the UV-resistant phototransfer agent in the phototransfer film is 0.4% to 10%, such as 0.4%, 1%, 3%, 5%, 8%, 10%, or any combination thereof.

[0042] In a specific embodiment of the present invention, the adhesive film body comprises the following components by weight: 100 parts of EVA resin, 0.5 to 1.5 parts of crosslinking agent, 0.1 to 1 part of co-crosslinking agent, 0.1 to 0.5 parts of antioxidant, 0.1 to 1 part of light stabilizer, and 0.3 to 1.5 parts of coupling agent.

[0043] In different embodiments, the amounts of the remaining components in the film bulk can be as follows, relative to 100 parts by weight of EVA resin: The amount of crosslinking agent can be 0.5 parts, 0.6 parts, 0.8 parts, 1 part, 1.2 parts, 1.5 parts, or any combination thereof; The amount of the crosslinking agent can be 0.1 parts, 0.2 parts, 0.5 parts, 0.8 parts, 1 part, or any combination thereof; The amount of antioxidant can be 0.1 parts, 0.2 parts, 0.3 parts, 0.4 parts, 0.5 parts, or any combination thereof; The amount of light stabilizer can be 0.1 parts, 0.2 parts, 0.5 parts, 0.8 parts, 1 part, or any combination thereof; The amount of coupling agent can be 0.3 parts, 0.5 parts, 0.8 parts, 1 part, 1.2 parts, 1.5 parts, or any combination thereof.

[0044] The types of additives can be exemplified as follows, but are not limited thereto: the crosslinking agent is selected from at least one of the peroxide crosslinking agents, such as tert-butyl peroxycarbonate-2-ethylhexyl ester; the co-crosslinking agent includes ethylene glycol dimethacrylate; the antioxidant includes any one or more of hindered phenolic antioxidants and phosphite antioxidants; the light stabilizer includes 4-benzoyloxy-2,2,6,6-tetramethylpiperidine; the coupling agent includes at least one of the silane coupling agents, such as epoxy-containing silane coupling agents, specifically γ-glycidoxypropyltrimethoxysilane.

[0045] In a specific embodiment of the present invention, the thickness of the phototransfer film is 0.05 to 2 mm, such as 0.05 mm, 0.08 mm, 0.1 mm, 0.3 mm, 0.5 mm, 0.8 mm, 1 mm, 1.2 mm, 1.5 mm, 1.8 mm, 2 mm or any combination thereof, but is not limited thereto, and can be conventionally adjusted according to the actual component application requirements.

[0046] The present invention also provides an optional method for preparing a light transfer film, comprising the following steps: mixing the film substrate with a UV-resistant light transfer agent in a certain proportion, and extruding and casting the mixture into a film.

[0047] In a specific embodiment of the present invention, the extrusion casting temperature is 75–90°C. In actual operation, the uniform mixing operation can be carried out in a mixer; the extrusion casting film formation operation can be carried out in a casting machine. Specifically, the extrusion casting temperature can be a range of 75°C, 80°C, 85°C, 90°C, or any combination thereof, and the specific extrusion casting temperature can be adjusted conventionally.

[0048] A fourth aspect of the present invention provides a photovoltaic module, including the light transfer film provided in the third aspect of the present invention.

[0049] In a specific embodiment of the present invention, the photovoltaic module includes the HJT photovoltaic module.

[0050] The product information used in specific embodiments of this invention may be as follows, but is not limited thereto: EVA resin: Sirbon V2825.

[0051] Example 1 This embodiment provides an optical transfer film and its preparation method, wherein the optical transfer film comprises the following components in parts by weight: 100 parts EVA resin, 1 part tert-butyl peroxycarbonate-2-ethylhexyl ester crosslinking agent, 0.5 parts ethylene glycol dimethacrylate co-crosslinking agent, 0.5 parts tri(nonylphenyl) phosphite antioxidant, 1 part 4-benzoyloxy-2,2,6,6-tetramethylpiperidine light stabilizer, 0.8 parts γ-glycidyl etheroxypropyltrimethoxysilane coupling agent, and 2 parts UV-resistant phototransfer agent.

[0052] The preparation method of the UV-resistant phototransfer agent includes: under nitrogen protection, adding 200 parts by weight of dehydrated xylene to a reaction vessel, then adding 100 parts by weight of methyl methacrylate, 10 parts by weight of a benzotriazole compound, 0.1 parts by weight of DBU, and 0.05 parts by weight of ethylene glycol to the xylene, reacting at 60°C for 5 hours, then cooling to room temperature, centrifuging to collect the precipitate, and washing the precipitate three times with ethanol to obtain the UV-resistant phototransfer agent. The structural formula of the benzotriazole compound is as follows: .

[0053] The molecular weight and molecular weight distribution of the UV-resistant phototransfer agent in this embodiment were tested by gel permeation chromatography (GPC) (the subsequent molecular weight and molecular weight distribution tests were conducted using the same method). The number-average molecular weight Mn was 10,000 and the molecular weight distribution width was 1.32.

[0054] The method for preparing the phototransfer film in this embodiment includes the following steps: weighing each material according to the proportion, mixing them evenly in a mixer, and then feeding them into a casting machine, where they are plasticized, extruded, stretched, pulled, and wound at 80°C to form a phototransfer film with a thickness of 0.5 mm.

[0055] Example 2 This embodiment refers to the light transfer film and its preparation method in Example 1, the only difference being that the UV-resistant light transfer agent in the light transfer film is different.

[0056] The UV-resistant phototransfer agent in this embodiment is prepared in accordance with Example 1, except that an equal weight of benzotriazole compounds as shown in the following formula is used to replace the benzotriazole compounds in Example 1.

[0057]

[0058] The UV-resistant phototransfer agent in this embodiment has a number-average molecular weight (Mn) of 11,000 and a molecular weight distribution width of 1.38.

[0059] Example 3 This embodiment refers to the light transfer film and its preparation method in Example 1, the only difference being that the UV-resistant light transfer agent in the light transfer film is different.

[0060] The UV-resistant phototransfer agent in this embodiment is prepared in accordance with Example 1, except that an equal weight of benzotriazole compounds as shown in the following formula is used to replace the benzotriazole compounds in Example 1.

[0061]

[0062] The UV-resistant phototransfer agent in this embodiment has a number-average molecular weight (Mn) of 9500 and a molecular weight distribution width of 1.44.

[0063] Example 4 This embodiment refers to the light transfer film and its preparation method in Example 1, the only difference being that the UV-resistant light transfer agent in the light transfer film is different.

[0064] The UV-resistant phototransfer agent in this embodiment is prepared in accordance with Example 1, except that an equal weight of benzotriazole compounds as shown in the following formula is used to replace the benzotriazole compounds in Example 1.

[0065]

[0066] The number-average molecular weight (Mn) of the UV-resistant phototransfer agent in this embodiment is 10,500, and the molecular weight distribution width is 1.35.

[0067] Example 5 This embodiment refers to the light transfer film and its preparation method in Example 1, the only difference being the amount of UV-resistant light transfer agent used in the light transfer film.

[0068] In this embodiment, the amount of UV-resistant phototransfer agent used is 0.5 parts.

[0069] Example 6 This embodiment refers to the light transfer film and its preparation method in Example 1, the only difference being the amount of UV-resistant light transfer agent used in the light transfer film.

[0070] In this embodiment, the amount of UV-resistant phototransfer agent used is 10 parts.

[0071] Example 7 This embodiment refers to the light transfer film and its preparation method in Example 1, the only difference being that the UV-resistant light transfer agent in the light transfer film is different.

[0072] The preparation of the UV-resistant phototransfer agent in this embodiment is the same as in Example 1, except that the amount of benzotriazole compound used is different. In this embodiment, the amount of benzotriazole compound used is 5 parts by weight.

[0073] The UV-resistant phototransfer agent in this embodiment has a number-average molecular weight (Mn) of 11,000 and a molecular weight distribution width of 1.29.

[0074] Example 8 This embodiment refers to the light transfer film and its preparation method in Example 1, the only difference being that the UV-resistant light transfer agent in the light transfer film is different.

[0075] The preparation of the UV-resistant phototransfer agent in this embodiment is the same as in Example 1, except that the amount of benzotriazole compound is different. In this embodiment, the amount of benzotriazole compound is 20 parts by weight.

[0076] The UV-resistant phototransfer agent in this embodiment has a number-average molecular weight (Mn) of 10,500 and a molecular weight distribution width of 1.34.

[0077] Example 9 This embodiment refers to the light transfer film and its preparation method in Example 1, the only difference being that the UV-resistant light transfer agent in the light transfer film is different.

[0078] The UV-resistant phototransfer agent in this embodiment is prepared in accordance with Example 1, except that the amount of benzotriazole compound used is different. In this embodiment, the amount of benzotriazole compound used is 3 parts by weight.

[0079] The number-average molecular weight (Mn) of the UV-resistant phototransfer agent in this embodiment is 8500, and the molecular weight distribution width is 1.22.

[0080] Example 10 This embodiment refers to the light transfer film and its preparation method in Example 1, the only difference being that the UV-resistant light transfer agent in the light transfer film is different.

[0081] The preparation of the UV-resistant phototransfer agent in this embodiment is the same as in Example 1, except that the amount of benzotriazole compound is different. In this embodiment, the amount of benzotriazole compound is 30 parts by weight.

[0082] The number-average molecular weight (Mn) of the UV-resistant phototransfer agent in this embodiment is 11,500, and the molecular weight distribution width is 1.47.

[0083] Comparative Example 1 Comparative Example 1 refers to the light transfer film and its preparation method in Example 1, except that in the preparation of the light transfer film, 0.02 parts by weight of a benzotriazole compound with the following structure is used to replace the UV-resistant light transfer agent in Example 1.

[0084]

[0085] Comparative Example 2 Comparative Example 2 refers to the light transfer film and its preparation method in Example 1, except that in the preparation of the light transfer film, an equal weight of light transfer agent is used to replace the UV-resistant light transfer agent in Example 1.

[0086] The preparation method of the light transfer agent in this comparative example includes: under nitrogen protection, adding 200 parts by weight of dehydrated xylene to a reaction vessel, adding 100 parts by weight of methyl methacrylate, 1 part by weight of benzotriazole compound and 0.01 parts by weight of azobisisobutyronitrile (AIBN) to the xylene, reacting at 60°C for 3 hours, then cooling to room temperature, centrifuging to collect the precipitate, and washing the precipitate three times with ethanol to obtain the light transfer agent.

[0087] The number-average molecular weight (Mn) of the light transfer agent in this comparative example is 15,000, and the molecular weight distribution width is 2.8.

[0088] Comparative Example 3 Comparative Example 3 refers to the light transfer film and its preparation method in Example 1, except that in the preparation of the light transfer film, 0.02 parts by weight of a benzotriazole compound with the following structure is used to replace the UV-resistant light transfer agent in Example 1.

[0089]

[0090] Experimental Example Photovoltaic module samples were prepared using light transfer films from different embodiments and comparative examples. The transmittance of the light transfer films was tested, referring to IEC61215 for the initial module power and UV 120kWh / m² of different photovoltaic modules. 2 The power output of the photovoltaic modules was then tested, as was the migration distance of the light transfer agent within the modules. The test results are shown in Table 1.

[0091] The preparation of the photovoltaic module samples to be tested includes: upper glass, upper encapsulant film, solar cells, lower encapsulant film, and lower glass, all of which are double-glass modules. During the lamination process, the heating plate temperature is 140℃, the vacuum time is 5 minutes to remove air between the layers, and then three pressurizations are performed to press the layers together. The first pressurization pressure is -80kPa to -70kPa, lasting 75 seconds; the second pressurization pressure is -50kPa to -40kPa, lasting 75 seconds; and the third pressurization pressure is -30kPa to -10kPa, lasting 10 minutes. After the vacuum is released, the laminated photovoltaic module is taken out. The upper encapsulant film (front of the module) is the light transfer encapsulant film of this invention, and the lower encapsulant film (back of the module) is the cutoff EVA encapsulant film (EV1050G1). The solar cells are 210-size HJT solar cells, and the final product is a 110-size module. The solar cells are connected in series, and there is a 0.5mm gap between the solar cells.

[0092] The method for testing the migration distance of the phototransfer agent in the module includes: first, placing the photovoltaic module sample to be tested in the dark, illuminating the back of the module with ultraviolet light, and observing and recording the fluorescence on both sides of the gap between the cells on the back of the photovoltaic module (no fluorescence under normal circumstances); then, placing the photovoltaic module sample to be tested in a 150℃ oven for 96 hours, taking it out and placing it in the dark, illuminating the back of the module with ultraviolet light, observing and recording the fluorescence on both sides of the gap between the cells on the back of the photovoltaic module (fluorescence on the back of the cells indicates phototransfer agent migration), and measuring the distance between the fluorescent edge and the edge of the cells with a ruler, which is recorded as the migration distance. Figure 1 The initial fluorescence on the back side of the component prepared using the phototransfer film of Example 1 of the present invention is shown under ultraviolet light irradiation. Figure 2 The fluorescence on the back of the component prepared by the phototransfer film of Example 1 of the present invention is observed after heating in an oven at 150°C for 96 hours and then irradiating with ultraviolet light. Figure 3 The fluorescence on the back of the module prepared using the phototransfer film of Comparative Example 3 was observed after heating in an oven at 150°C for 96 hours and then irradiated with ultraviolet light.

[0093] Table 1 Performance test results for different phototransfer films

[0094] The test results above show that the copolymer obtained by anionic polymerization of benzotriazole compounds containing unsaturated bonds and methyl methacrylate in this invention can improve dispersion uniformity, reduce fluorescence quenching, and promote fluorescence emission through the copolymer structure, thereby improving fluorescence quantum efficiency. Furthermore, the methyl methacrylate segments encapsulate the benzotriazole compounds, forming a physical barrier and improving the UV aging resistance of the light transfer agent. This results in enhanced light transfer performance of the corresponding light transfer film, increased component power, and improved UV resistance at 120 kWh / m². 2 The power degradation rate of the components decreases afterward. Furthermore, the light transfer agent includes a copolymer obtained by copolymerizing benzotriazole compounds containing unsaturated bonds with methyl methacrylate. The copolymer ends with unsaturated bonds, which can participate in the reaction during the lamination process of photovoltaic modules, modifying the EVA resin and effectively suppressing its migration problem.

[0095] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A UV-aging resistant phototransfer agent, characterized in that, The copolymer is prepared by anionic polymerization of a benzotriazole compound containing an unsaturated bond and methyl methacrylate; The benzotriazole compound containing an unsaturated bond is selected from at least one of the following formulae I-II: 、 ； wherein R in formulae I-II is each independently selected from , .

2. The UV aging resistant phototransfer agent according to claim 1, characterized in that, The mass ratio of the benzotriazole compound containing an unsaturated bond to the methyl methacrylate is (5-20):

100.

3. The UV aging resistant phototransformable agent of claim 1, wherein, The copolymer has at least one of the following characteristics: (1) The number average molecular weight of the copolymer is 8000-15000; (2) The molecular weight distribution width of the copolymer is 1.2-1.

5.

4. Process for the preparation of a phototransformable agent resistant to UV ageing according to any one of claims 1 to 3, characterised in that, The method comprises the following steps: anionic polymerization of a benzotriazole compound containing an unsaturated bond and methyl methacrylate in a solvent under the action of a catalyst and an initiator, collection of solid phase after the reaction, and washing to obtain the UV-aging-resistant phototransfer agent.

5. The preparation method according to claim 4, characterized in that, The catalyst is 1,8-diazabicyclo[5.4.0]undec-7-ene; Preferably, the amount of the catalyst is 0.05%-2% of the mass of the methyl methacrylate.

6. The preparation method according to claim 4, characterized in that, The initiator is ethylene glycol. Preferably, the amount of the initiator is 0.05%-0.1% of the mass of the methyl methacrylate.

7. The preparation method according to claim 4, characterized in that, In the anionic polymerization, the reaction temperature is 50-70℃, and the reaction time is 4-6h.

8. A photo-adhesive film, characterized by, The phototransfer adhesive film comprises a film body and the UV-aging-resistant phototransfer agent dispersed in the film body.

9. The photoadhesive film according to claim 8, wherein, In the phototransfer adhesive film, the mass fraction of the UV-aging-resistant phototransfer agent is 0.4%-10%.

10. A photovoltaic module characterized by, The phototransfer adhesive film comprises the phototransfer adhesive film according to claim 8 or 9.

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