Anti-radiation photovoltaic encapsulation adhesive film, preparation method thereof and photovoltaic module

Abstract

The application relates to the technical field of photovoltaic adhesive films, and discloses an anti-radiation photovoltaic packaging adhesive film, a preparation method thereof and a photovoltaic module. The adhesive film is a multilayer co-extrusion composite structure formed through co-extrusion molding and irradiation, and comprises an upper surface layer, a middle functional layer and a lower surface layer; the upper surface layer is a radiation-resistant polymer matrix (such as EVA-g-St, EVA-g-(alpha-MeSt), POE-g-St or an EVA / POE-aromatic resin blend); the middle functional layer comprises a packaging resin matrix, an anti-radiation agent (a nanoscale radiation protection material such as a rare earth oxide, a heavy metal oxide, a boron-containing compound or a high molecular derivative of a benzotriazole type ultraviolet absorber) and a stabilizer; and the lower surface layer is a bonding surface layer formed by a light-transmitting bonding resin. The adhesive film has good radiation resistance, and the light transmittance, bonding property, elongation at break retention rate, yellowing resistance and module power attenuation resistance of the adhesive film after accelerated irradiation are obviously improved, so that the service life of the module under strong radiation can be prolonged.

Description

Technical Field

[0001] This invention relates to the field of photovoltaic encapsulant technology, specifically to a radiation-resistant photovoltaic encapsulant film, its preparation method, and a photovoltaic module. Background Technology

[0002] Photovoltaic power generation technology is increasingly being used in areas of the Earth's surface with strong radiation (such as plateaus). In these environments, solar cells and their encapsulation materials are continuously exposed to ionizing radiation such as high-energy particles (electrons and protons) and gamma rays.

[0003] Existing photovoltaic encapsulation films, such as ordinary EVA films and POE films (as shown in publication number CN117143539A), will suffer severe radiation damage under strong radiation, mainly manifested as follows:

[0004] (1) Imbalance between crosslinking and degradation: The polymer molecular chains undergo random breakage (degradation) or excessive crosslinking, resulting in a sharp decline in the mechanical properties (tensile strength, elongation) of the film, making it brittle or hard.

[0005] (2) Discoloration and decrease in light transmittance: Radiation induces the formation of color centers and oxidation inside the material, resulting in yellowing and browning of the film, and a significant decrease in light transmittance, which seriously affects the photoelectric conversion efficiency of the photovoltaic module.

[0006] (3) Interface failure: The bonding strength between the adhesive film and the solar cell and photovoltaic glass is weakened due to radiation damage, resulting in the delamination of the photovoltaic module, loss of protection and insulation function for the solar cell, and ultimately failure of the photovoltaic module.

[0007] Furthermore, current high-performance photovoltaic modules for space applications typically employ extremely expensive specialized photovoltaic glass or rigid photovoltaic cover plates, which places extremely high demands on the overall structural design and results in high costs. In areas with strong ground radiation, the lifespan and reliability of ordinary photovoltaic modules cannot be guaranteed. Therefore, there is an urgent need to develop a specialized radiation-resistant photovoltaic encapsulating film that is relatively cost-effective, possesses excellent radiation resistance, can maintain high light transmittance over a long period, exhibits good adhesion, good mechanical properties, and provides stable power output for photovoltaic modules. Summary of the Invention

[0008] The purpose of this invention is to overcome the shortcomings of the prior art and provide a radiation-resistant photovoltaic encapsulating film, its preparation method, and a photovoltaic module.

[0009] Based on this, the present invention discloses a radiation-resistant photovoltaic encapsulating film, which is a multi-layer co-extruded composite structure formed by co-extrusion molding and irradiation, comprising an upper surface layer, an intermediate functional layer and a lower surface layer in sequence.

[0010] The upper surface layer is an irradiation surface layer facing the radiation source. Its main function is to absorb and dissipate part of the incident radiation energy. The material of the upper surface layer is a radiation-resistant polymer matrix. The radiation-resistant polymer matrix is ​​at least one of EVA-g-St (styrene-grafted modified ethylene-vinyl acetate copolymer), EVA-g-(α-MeSt) (α-methylstyrene-grafted modified ethylene-vinyl acetate copolymer), POE-g-St (styrene-grafted modified polyolefin elastomer, i.e., styrene grafted onto a polyolefin elastomer backbone), EVA-aromatic resin blend (i.e., a blend of EVA and aromatic resin), and POE-aromatic resin blend (i.e., a blend of POE and aromatic resin). The aromatic resin can be SEBS, SEPS, or PC.

[0011] EVA-g-St enhances its stability through structural modification. The vinyl acetate segment of ordinary EVA is relatively sensitive to radiation. By grafting styrene-type compounds, benzene rings (aromatic groups) are introduced into the EVA molecular chain. These benzene rings act as energy absorption traps and free radical quenchers, absorbing radiation energy and capturing destructive free radicals generated by radiation. This significantly improves the radiation resistance of the base EVA resin, making it less susceptible to radiation damage and ensuring the overall structural integrity and long-term reliability of the film, which is fundamental to its radiation resistance. EVA-g-(α-MeSt): α-methylstyrene grafted onto ethylene-vinyl acetate copolymer. The steric hindrance effect of the methyl group improves the polymer's thermal stability. POE-g-St: Styrene grafted onto a polyolefin elastomer backbone. POE itself has better hydrolysis resistance and PID resistance than EVA. Grafting onto POE yields a top layer material with superior overall performance. In EVA-aromatic resin blends (or POE-aromatic resin blends), the aromatic resins such as SEBS or SEPS are styrene-polyolefin-styrene block copolymers with a large number of benzene rings and good compatibility with EVA / POE. PC contains benzene rings and ester groups, and has good impact resistance and radiation resistance. Adding these components can significantly improve the toughness, weather resistance and intrinsic radiation resistance of the blends.

[0012] The intermediate functional layer is the core protective layer, which includes the following raw materials: encapsulating resin matrix, anti-radiation agent and stabilizer, wherein the anti-radiation agent and stabilizer account for 0.5-10% and 0.15-3% of the mass of the encapsulating resin matrix, respectively; the anti-radiation agent is a nanoscale radiation protection material, selected from at least one of rare earth oxides, heavy metal oxides, boron-containing compounds, and polymer derivatives of benzotriazole type ultraviolet absorbers.

[0013] The lower surface layer is an adhesive layer facing the photovoltaic cell, and it is required to have excellent light transmittance and stable adhesion performance. Its material is a light-transmitting adhesive resin.

[0014] In practice, the preparation process of EVA-g-St includes: mixing the following materials in parts by weight and feeding them into a twin-screw extruder: 5-20 parts of styrene (St) monomer, 100 parts of EVA particles (matrix, VA content 28-33%), 0.1-10 parts of dicumyl peroxide (DCP, initiator), and 0.5-2 parts of maleic anhydride-grafted polyethylene (PE-g-MAH), which can promote compatibility with the intermediate functional layer during subsequent co-extrusion. The twin-screw extruder is configured with the following temperatures for each zone: Zone 1 (feeding / plasticizing): 120-140°C, allowing EVA to melt and absorb monomers; Zones 2 / 3 (reaction zone): 160-180°C, where the initiator decomposes, triggering the grafting reaction. This section of the screw should provide strong mixing and sufficient residence time (typically 1-3 minutes); Subsequent zone (devouring / homogenization): 170-190°C, where unreacted styrene monomers and byproducts (such as acetaldehyde) are removed through a vacuum vent to prevent bubbles and improve product purity. The reacted melt is then extruded through a die, water-cooled, pelletized, and dried to obtain EVA-g-St granules. In the EVA-g-St, the grafting rate of styrene units is 5-15%. This grafting rate range effectively improves radiation resistance while maintaining a balance between the original processability and transparency of EVA.

[0015] The preparation processes for EVA-g-(α-MeSt) and POE-g-St are the same as those for EVA-g-St, with differences only in the grafting material and matrix. The preparation process for EVA-aromatic resin blends or POE-aromatic resin blends (where the mass percentage of aromatic resin in the blend is preferably 10-20%) involves blending using a twin-screw extruder without adding dicumyl peroxide (DCP), and all other preparation processes are the same as those for EVA-g-St.

[0016] Preferably, the radiation-resistant polymer matrix is ​​at least one of EVA-g-St and POE-g-St, with a grafting rate of 5-15%.

[0017] Preferably, the encapsulating resin matrix is ​​at least one of EVA (ethylene-vinyl acetate copolymer), POE (polyolefin elastomer), and silicone-modified polyolefin.

[0018] Preferably, the particle size of the nanoscale radiation protection material is 10-500 nm; the rare earth oxide is nanoscale gadolinium oxide (Gd₂O₃) and / or europium oxide (Eu₂O₃); the heavy metal oxide is nanoscale bismuth oxide (Bi₂O₃) and / or tungsten oxide (WO₃); and the boron-containing compound is nanoscale boron nitride (BN) and / or boron carbide (B₄C). The main function of this nanoscale radiation protection material is to attenuate high-energy particles through scattering and absorption, and to effectively quench free radicals generated by radiation.

[0019] More preferably, the anti-radiation agent is nano-gadolinium oxide or nano-boron nitride.

[0020] Preferably, the stabilizer comprises a composite antioxidant and a metal ion chelating agent, wherein the composite antioxidant and the metal ion chelating agent account for 0.1-2% and 0.05-1% of the mass of the encapsulating resin matrix, respectively.

[0021] More preferably, the composite antioxidant is a combination of a hindered phenolic antioxidant and a phosphite antioxidant; the metal ion chelating agent is a β-diketone compound.

[0022] Preferably, the light-transmitting adhesive resin is EVA with a VA content of 28-40% (high VA content EVA), peroxide cross-linked POE, or addition-type liquid silicone rubber. The lower surface is oriented towards the photovoltaic cell, requiring excellent light transmittance and stable adhesion performance.

[0023] Preferably, the thickness ratio of the upper surface layer, the middle functional layer and the lower surface layer is 0.5-1.5:7-9:0.5-1.5; the total thickness of the radiation-resistant photovoltaic encapsulation film is 0.3-0.6 mm.

[0024] This invention also discloses a method for preparing a radiation-resistant photovoltaic encapsulating film, comprising:

[0025] S1. Raw material pretreatment and preparation of anti-radiation masterbatch: The required polymer or resin base material for each layer is dried in a vacuum oven; the anti-radiation agent is pre-dispersed with a portion of the encapsulating resin matrix, and then melt-blended and granulated using a twin-screw extruder to produce anti-radiation masterbatch; wherein the mass percentage of the anti-radiation agent in the anti-radiation masterbatch is 10-40%;

[0026] S2, Three-layer co-extrusion casting: The radiation-resistant polymer matrix of the upper layer, the encapsulating resin matrix of the middle functional layer, the mixture of radiation-resistant masterbatch and stabilizer, and the light-transmitting adhesive resin of the lower layer are respectively put into three independent extruders, and melted and cast through a three-layer co-extrusion die at a temperature of 100-150℃ to obtain the initial composite film.

[0027] S3. Electron beam pre-irradiation treatment: Under inert gas protection, the initial composite film is scanned and irradiated with an electron beam of 5-30 kGy to controllably introduce a preliminary cross-linked network structure, improve the initial mechanical strength of the film, and pre-consume some of the radiation-sensitive unstable structures.

[0028] S4. Cool and post-process the initial composite film after irradiation (e.g., rapidly cool and shape it with a cooling roller, cover it with a protective film, and roll it up) to obtain the radiation-resistant photovoltaic encapsulating film.

[0029] The present invention also discloses a photovoltaic module, which includes a photovoltaic front panel, a first encapsulating film, a photovoltaic cell, a second encapsulating film, and a photovoltaic back panel stacked from top to bottom; the first encapsulating film is a radiation-resistant photovoltaic encapsulating film as described above in the present invention, and the upper and lower surfaces face the photovoltaic front panel and the photovoltaic cell, respectively.

[0030] The anti-radiation photovoltaic encapsulating film of the present invention significantly improves its resistance to ionizing radiation, long-term optical stability and interfacial adhesion stability through synergistic design at the molecular structure and composite material levels. It has high reliability and is suitable for solar cell encapsulation in high-altitude and other strong ionizing radiation environments.

[0031] Compared with the prior art, the present invention has at least the following beneficial effects:

[0032] The anti-radiation photovoltaic encapsulation film of the present invention is a multi-layer co-extruded composite structure formed by co-extrusion molding and irradiation. The upper surface layer uses a high radiation-resistant polymer matrix as the first line of radiation protection. The middle functional layer uses an encapsulation resin matrix, an anti-radiation agent, and a stabilizer to uniformly disperse the anti-radiation agent (a nano-scale radiation protection material selected from at least one of rare earth oxides, heavy metal oxides, boron-containing compounds, and benzotriazole-type ultraviolet absorbers) to achieve further radiation protection. The lower surface layer is an adhesive layer made of a light-transmitting adhesive resin to ensure optical and adhesive properties. Thus, this radiation-resistant photovoltaic encapsulation film, through co-extrusion of an upper surface layer made of a radiation-resistant polymer matrix, an intermediate functional layer uniformly dispersed with radiation-resistant agents and stabilizers, and a lower surface layer made of a light-transmitting adhesive resin, introduces intrinsic radiation-resistant polymers and nanoscale radiation-resistant agents, as well as multiple radiation-resistant layers, after irradiation such as with an electron beam. This significantly enhances its radiation resistance performance. Consequently, the film's light transmittance after accelerated irradiation, adhesion to photovoltaic glass, elongation at break retention, resistance to yellowing, and resistance to power attenuation after photovoltaic module irradiation are all significantly improved, demonstrating long-term reliability.

[0033] In addition, the intermediate functional layer composite stabilizer system, through irradiation processes such as electron beams, can further inhibit the aging and degradation of the film under long-term radiation and thermo-oxidative conditions, significantly extending the service life of photovoltaic modules in strong radiation environments. Detailed Implementation

[0034] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to specific embodiments.

[0035] Example 1

[0036] This embodiment provides an anti-radiation photovoltaic encapsulation film, which has a multi-layer co-extruded composite structure, comprising an upper surface layer, an intermediate functional layer, and a lower surface layer.

[0037] The upper surface layer is the irradiated surface layer, facing the front of the photovoltaic panel, and is made of a radiation-resistant polymer matrix, which is EVA-g-St (styrene-grafted modified ethylene-vinyl acetate copolymer).

[0038] The preparation process of this EVA-g-St includes the following steps: 100 parts by weight of EVA resin (VA content 33%, grade V33301, provided by Asia Polymer Co., Ltd.), 15 parts by weight of styrene monomer (provided by Hubei Jusheng Technology Co., Ltd.), 0.5 parts by weight of dicumyl peroxide (DCP, provided by Jiangsu Daoming Chemical Co., Ltd.), and 1 part by weight of maleic anhydride grafted polyethylene (PE-g-MAH, grade 900E, provided by Nanjing Feiteng New Materials Co., Ltd.) (Provided by Material Technology Co., Ltd.) Premixed in a high-speed mixer for 5 minutes to obtain premixed material; the premixed material is fed into a twin-screw extruder, and the extruder temperature is set sequentially from the feed port to the die head as follows: 130°C, 150°C, 170°C, 175°C, 180°C, 185°C (die head). A vacuum exhaust port is set in the 175°C section for devolatilization, and the screw speed is 150 rpm. After extrusion, water cooling, and pelletizing, EVA-g-St particles (with a grafting rate of 8%) are obtained.

[0039] The intermediate functional layer is the core protective layer, which includes the following raw materials: an encapsulating resin matrix, a high-efficiency radiation-resistant agent, and a stabilizer. The encapsulating resin matrix is ​​EVA resin with a VA content of 33% (brand name V33301, provided by Asia Polymer Co., Ltd.); the radiation-resistant agent is nano-gadolinium oxide (particle size 50nm, brand name Gd2O3, gadolinium oxide nanoparticles, provided by Xi'an Ruixi Biotechnology Co., Ltd.), with an addition amount accounting for 5wt% of the encapsulating resin matrix mass; the stabilizer includes a composite antioxidant (comprising antioxidant 1010 and antioxidant 168 in a 1:2 mass ratio, with the addition amount accounting for 1wt% of the encapsulating resin matrix mass) and a metal ion chelating agent (β-diketone compound: stearoylbenzoylmethane, brand name SBM-50, provided by Anhui Jiaxian Functional Additives Co., Ltd.; the addition amount of this metal ion chelating agent accounts for 0.5wt% of the encapsulating resin matrix mass) as stabilizer D.

[0040] The lower surface layer is the adhesive layer, facing the photovoltaic cell. It is made of a light-transmitting adhesive resin, which is a light-transmitting EVA resin with a VA content of 40% (brand name Elvax® 40W, provided by DuPont).

[0041] This embodiment provides a method for preparing a radiation-resistant photovoltaic encapsulating film, comprising:

[0042] S1. Preparation of anti-radiation masterbatch: First, the anti-radiation agent (nano Gd2O3) is pre-dispersed with part of the encapsulation resin matrix (EVA resin with VA content of 33%), and then melt-blended and granulated by a twin-screw granulator to prepare anti-radiation masterbatch (the mass ratio of nano Gd2O3 in the anti-radiation masterbatch is 20%).

[0043] S2. Set the parameters of the three-layer co-extrusion die according to the thickness ratio of 1:8:1. Feed the radiation-resistant polymer matrix (EVA-g-St) of the upper surface layer, the mixed intermediate functional layer raw materials (the remaining encapsulating resin matrix, radiation-resistant masterbatch and stabilizer), and the light-transmitting adhesive resin (light-transmitting EVA resin with 40% VA content) of the lower surface layer into three extruders respectively. Through a three-layer co-extrusion die, melt the three layers and co-extrude them at 130°C to obtain an initial composite film with a total thickness of 0.5 mm.

[0044] S3. Under a nitrogen atmosphere, the initial composite film is uniformly irradiated with an electron beam dose of 15 kGy using an electron accelerator.

[0045] S4. The irradiated composite film is rapidly cooled and shaped by cooling rollers, covered with a protective film, and then wound up to obtain an anti-radiation photovoltaic encapsulation film of this embodiment.

[0046] A photovoltaic module according to this embodiment includes a photovoltaic front panel (photovoltaic glass), a first encapsulating film, a photovoltaic cell, a second encapsulating film, and a photovoltaic back panel stacked from top to bottom; wherein, the first encapsulating film is a radiation-resistant photovoltaic encapsulating film as described above in this embodiment.

[0047] Example 2

[0048] This embodiment describes a radiation-resistant photovoltaic encapsulating film, its preparation method, and a photovoltaic module. Referring to Example 1, the difference lies in that: the radiation-resistant polymer matrix of the upper surface layer is replaced with POE-g-St (styrene-grafted modified polyolefin elastomer with a grafting rate of 8%; the preparation process of POE-g-St follows the same process as EVA-g-St in Example 1, and the POE grade is PV8669, provided by Dow Chemical); and the radiation-resistant agent in the middle functional layer is replaced with 3wt% nano-boron nitride (BN, grade CW-BN-001, provided by Shanghai Chaowei Nanotechnology Co., Ltd.); other raw material compositions and preparation steps are the same as in Example 1.

[0049] Comparative Example 1

[0050] This comparative example provides a radiation-resistant photovoltaic encapsulating film, its preparation method, and a photovoltaic module. Referring to Example 1, the difference between Example 1 and Example 2 is that the upper surface layer is made of a light-transmitting adhesive resin (light-transmitting EVA resin with 40% VA content) instead of the lower surface layer, i.e., the radiation-resistant polymer matrix A is not added to the upper surface layer; the other raw material composition and preparation steps are the same as in Example 1.

[0051] Comparative Example 2

[0052] This comparative example provides a radiation-resistant photovoltaic encapsulating film, its preparation method, and a photovoltaic module. The difference between this comparative example and Example 1 is that no radiation-resistant agent is added to the intermediate functional layer; the composition of other raw materials and preparation steps are the same as in Example 1.

[0053] Comparative Example 3

[0054] This comparative example provides a radiation-resistant photovoltaic encapsulating film, its preparation method, and a photovoltaic module. It is based on Example 1, but differs from Example 1 in that the initial composite film is not irradiated with an electron beam (i.e., step S3 of Example 1 is omitted); the composition of other raw materials and preparation steps are the same as in Example 1.

[0055] Comparative Example 4

[0056] This comparative example of a photovoltaic module, referring to Example 1, differs from Example 1 in that: in this comparative example of a photovoltaic module, the first encapsulating film is a commercially available ordinary photovoltaic EVA film (without special anti-radiation design; grade F406P, provided by Hangzhou Foster Applied Materials Co., Ltd.).

[0057] Performance testing

[0058] The encapsulant films and photovoltaic modules manufactured in Examples 1-2 and Comparative Examples 1-4 were subjected to performance tests, and the test results are shown in Table 1 below:

[0059] (1) 380-1100nm transmittance: The test was conducted in accordance with the standard GB / T 2410-2008 "Determination of transmittance and haze of transparent plastic".

[0060] (2) Peel strength with photovoltaic glass: The test was conducted in accordance with the standard GB / T 2790-1995 "Test method for peel strength of adhesives at 180°, flexible materials to rigid materials".

[0061] (3) Elongation at break: The test was conducted in accordance with the standard GB / T 1040.1-2025 "Determination of tensile properties of plastics - Part 1: General".

[0062] (4) Yellowing index Δb: The test was conducted in accordance with the standard GB / T 7921-2008 "Uniform color space and color difference formula" and the standard ASTM E313-20 (2025) "Standard practice for calculating yellowness and whiteness index from instrument-measured color coordinates".

[0063] (5) Power decay and appearance after accelerated irradiation: The test was conducted in accordance with the standard IEC 61215-2:2021 "Ground-mounted photovoltaic (PV) modules. Design qualification and type approval. Part 2: Test procedures".

[0064] Table 1

[0065]

[0066] Accelerated irradiation experiments were conducted in a room temperature air environment using a cobalt-60 gamma-ray source, with a total cumulative dose of 1×10^6 Gy (simulating long-term exposure to a strong radiation environment).

[0067] The radiation-resistant photovoltaic encapsulating film (hereinafter referred to as the film) of Example 1 underwent irradiation tests before and after: its light transmittance (380-1100nm) changed from the initial 91.2% to 83.5%, and the peel strength with photovoltaic glass decreased from 121N / cm to 92N / cm; the elongation at break retention rate was greater than 80%, which is far superior to ordinary photovoltaic EVA films (such as Comparative Example 4); the yellowing index Δb was also low, only 2.1; after the film of Example 1 was applied to photovoltaic modules, the power attenuation of the photovoltaic modules was more than 50% lower than that of the control group (Comparative Example 4) using ordinary photovoltaic EVA films. The performance test results of the film of Example 2 before and after accelerated irradiation were also significantly better than those of Comparative Examples 1-4.

[0068] The test results of Comparative Examples 1-4 in Table 1 show that if the upper surface layer or intermediate functional layer of the encapsulant film is not made with a radiation-resistant polymer matrix, and if no radiation-resistant agent is added, or if the initial composite film is not irradiated with an electron beam, the aforementioned properties of the encapsulant film after accelerated irradiation (such as light transmittance, peel strength from photovoltaic glass, yellowing resistance, and power attenuation rate of photovoltaic modules) will all deteriorate significantly. In particular, the ordinary photovoltaic EVA encapsulant film of Comparative Example 4, which has not undergone any radiation-resistant treatment, showed severe yellowing, a drop in light transmittance to 33.5%, almost no adhesion to photovoltaic glass, a very low elongation at break retention rate, and was prone to embrittlement and cracking after accelerated irradiation, easily delaminating from the photovoltaic glass, leading to photovoltaic module failure.

[0069] In summary, the anti-radiation photovoltaic encapsulating films of Examples 1-2 of the present invention, through the synergistic combination of an upper surface layer made of a radiation-resistant polymer matrix, an intermediate functional layer containing both anti-radiation agents and stabilizers, and a lower surface layer made of a light-transmitting adhesive resin, can greatly improve their anti-radiation performance after electron beam irradiation treatment. The light transmittance, adhesion to photovoltaic glass, elongation at break retention, yellowing resistance, and power attenuation resistance of photovoltaic modules after accelerated irradiation are all significantly improved.

[0070] Although preferred embodiments of the present invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of the embodiments of the present invention.

[0071] The technical solution provided by the present invention has been described in detail above. Specific examples have been used to illustrate the principle and implementation of the present invention. The description of the above embodiments is only for the purpose of helping to understand the method and core idea of ​​the present invention. At the same time, for those skilled in the art, there will be changes in the specific implementation and application scope based on the idea of ​​the present invention. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A radiation-resistant photovoltaic encapsulating film, characterized in that, It is a multi-layer co-extruded composite structure formed by co-extrusion molding and irradiation, which includes an upper surface layer, an intermediate functional layer and a lower surface layer in sequence; The upper surface layer is an irradiated surface layer, and its material is a radiation-resistant polymer matrix; the radiation-resistant polymer matrix is ​​at least one of EVA-g-St, EVA-g-(α-MeSt), POE-g-St, EVA-aromatic resin blend, and POE-aromatic resin blend. The intermediate functional layer comprises the following raw materials: an encapsulating resin matrix, a radiation-resistant agent, and a stabilizer, wherein the radiation-resistant agent and the stabilizer account for 0.5-10% and 0.15-3% of the mass of the encapsulating resin matrix, respectively; the radiation-resistant agent is a nanoscale radiation protection material selected from at least one of rare earth oxides, heavy metal oxides, and boron-containing compounds. The encapsulating resin matrix is ​​at least one of EVA, POE, and silicon-modified polyolefin; The nanoscale radiation protection material has a particle size of 10-500 nm; the rare earth oxide is nanoscale gadolinium oxide and / or europium oxide; the heavy metal oxide is nanoscale bismuth oxide and / or tungsten oxide; the boron-containing compound is nanoscale boron nitride and / or boron carbide. The stabilizer comprises a composite antioxidant and a metal ion chelating agent, wherein the composite antioxidant and the metal ion chelating agent account for 0.1-2% and 0.05-1% of the mass of the encapsulating resin matrix, respectively. The composite antioxidant is a combination of a hindered phenolic antioxidant and a phosphite antioxidant; the metal ion chelating agent is a β-diketone compound. The lower surface layer is an adhesive layer, and its material is a light-transmitting adhesive resin.

2. The anti-radiation photovoltaic encapsulating film according to claim 1, characterized in that, The radiation-resistant polymer matrix is ​​at least one of EVA-g-St and POE-g-St, with a grafting rate of 5-15%.

3. The anti-radiation photovoltaic encapsulating film according to claim 1, characterized in that, The radiation-resistant agent is nano-gadolinium oxide or nano-boron nitride.

4. The anti-radiation photovoltaic encapsulating film according to claim 1, characterized in that, The light-transmitting adhesive resin is EVA with a VA content of 28-40%, peroxide cross-linked POE, or addition-type liquid silicone rubber.

5. The anti-radiation photovoltaic encapsulating film according to claim 1, characterized in that, The thickness ratio of the upper surface layer, the middle functional layer and the lower surface layer is 0.5-1.5:7-9:0.5-1.5; the total thickness of the radiation-resistant photovoltaic encapsulation film is 0.3-0.6 mm.

6. A method for preparing a radiation-resistant photovoltaic encapsulating film according to any one of claims 1-5, characterized in that, include: S1. Preparation of anti-radiation masterbatch: The anti-radiation agent is pre-dispersed with a portion of the encapsulating resin matrix, then melt-blended and granulated to prepare anti-radiation masterbatch; wherein the anti-radiation agent accounts for 10-40% of the mass of the anti-radiation masterbatch; S2, Three-layer co-extrusion casting: The radiation-resistant polymer matrix of the upper layer, the encapsulating resin matrix of the middle functional layer, the mixture of radiation-resistant masterbatch and stabilizer, and the light-transmitting adhesive resin of the lower layer are respectively put into three independent extruders, and the initial composite film is obtained by melt three-layer co-extrusion casting. S3. Electron beam pre-irradiation treatment: Under inert gas protection, the initial composite film is scanned and irradiated with an electron beam of 5-30 kGy. S4. Cool and post-process the initial composite film after irradiation to obtain the radiation-resistant photovoltaic encapsulation film.

7. A photovoltaic module, characterized in that, It includes a photovoltaic front panel, a first encapsulating film, a photovoltaic cell, a second encapsulating film, and a photovoltaic back panel stacked sequentially from top to bottom; the first encapsulating film is a radiation-resistant photovoltaic encapsulating film as described in any one of claims 1-5, and the upper and lower surfaces face the photovoltaic front panel and the photovoltaic cell, respectively.

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