Impact-resistant photovoltaic encapsulant film, preparation method thereof and photovoltaic module

Abstract

This invention discloses an impact-resistant photovoltaic encapsulating film, its preparation method, and a photovoltaic module. The photovoltaic encapsulating film comprises multiple layers of unidirectional prepreg tape laminated together. The unidirectional prepreg tape is obtained by melt impregnation of thermoplastic resin and continuous fibers surface-treated with a coupling agent. The thermoplastic resin includes polyolefin elastomer (POE) and POE grafts. During the melt impregnation process, the continuous fibers surface-treated with the coupling agent and the POE grafts undergo a chemical reaction to achieve compatibility. This invention employs a pre-melt impregnation followed by crosslinking technique. The uncrosslinked POE resin has good fluidity and can be fully melt-impregnated with the continuous fibers. Electron beam irradiation post-treatment technology allows the impregnated base film to undergo a crosslinking reaction, resulting in a fiber-reinforced impact-resistant photovoltaic encapsulating film. The film prepared by this invention meets industry technical standards for UV resistance, aging resistance, and impact resistance, while also being low-cost and simple to manufacture, making it widely applicable in the field of lightweight flexible photovoltaic modules.

Description

Technical Field

[0001] This invention belongs to the field of photovoltaic module technology, specifically relating to an impact-resistant photovoltaic encapsulation film, its preparation method, and a photovoltaic module. Background Technology

[0002] Lightweight flexible photovoltaic modules are gaining popularity due to their thin and flexible characteristics. However, compared to traditional glass photovoltaic modules, their impact resistance is significantly weaker. Therefore, lightweight flexible modules typically require the addition of harder impact-resistant materials, such as epoxy fiberglass prepreg, to improve their impact resistance. However, epoxy fiberglass prepreg has a short room temperature storage period, generally 15-30 days, and is easily degraded by humidity and temperature. Therefore, developing new impact-resistant layer materials to replace traditional epoxy fiberglass prepreg is urgently needed.

[0003] Polyolefin elastomer (POE) is a commonly used polymer material in the photovoltaic field. Due to its low water vapor permeability, it is often used as a photovoltaic encapsulation film. However, POE resin is relatively soft and has poor impact resistance, generally requiring modification to improve its impact resistance. Melting and extruding POE resin to form a melt, followed by melt impregnation with continuous fibers, can significantly improve its impact resistance. To ensure thorough melt impregnation with continuous fibers, this invention employs electron beam irradiation post-treatment technology, first melt impregnating and then cross-linking to prepare the photovoltaic encapsulation film. The continuous fibers, after surface treatment with a silane coupling agent, can chemically react with the maleic anhydride or glycidyl methacrylate groups grafted onto POE, thus achieving good interfacial compatibility. By combining continuous fiber melt impregnation technology with electron beam irradiation post-treatment technology, the prepared photovoltaic encapsulation film significantly improves the material's impact resistance while ensuring good encapsulation performance, making it widely applicable in the field of lightweight flexible photovoltaic modules! Summary of the Invention:

[0004] To achieve the above objectives and address the problems and shortcomings of existing technologies, this invention provides a method for preparing an impact-resistant photovoltaic encapsulating film, comprising the following steps:

[0005] A method for preparing an impact-resistant photovoltaic encapsulating film includes the following steps:

[0006] S1. The dried polyolefin elastomer resin, polyolefin elastomer graft, crosslinking agent, tackifier, antioxidant and UV stabilizer are mixed in an internal mixer and then placed in a single screw extruder for melt extrusion granulation to obtain a special material for polyolefin elastomer hot melt adhesive.

[0007] S2. The polyolefin elastomer hot melt adhesive material is placed in a twin-screw extruder and melted to form a resin melt. The resin melt is then injected into an impregnation mold and impregnated with continuous fibers treated with silane coupling agent that have been stretched by traction. After cooling, a unidirectional prepreg tape is obtained, and after multi-layer lamination, a photovoltaic encapsulation base film is obtained.

[0008] S3. The photovoltaic encapsulation base film is placed under an electron accelerator for electron beam irradiation crosslinking and curing to prepare the impact-resistant photovoltaic encapsulation film.

[0009] Further, before S1, the polyolefin elastomer resin is placed in a forced-air drying oven and dried at 60-80°C for 12-24 hours, and then cooled to room temperature with cold air to obtain a dried polyolefin elastomer, wherein the melt index of the polyolefin elastomer resin is 20-30 g / 10 min.

[0010] Further, the polyolefin elastomer graft described in S1 includes any one of the following: polyolefin elastomer grafted with maleic anhydride or polyolefin elastomer grafted with glycidyl methacrylate, with an addition ratio of 5wt% to 10wt% of the polyolefin elastomer resin.

[0011] Further, the crosslinking agent comprises any one or any combination of the following: triallyl isocyanurate, trimethylolpropane trimethacrylate, and triallyl cyanurate, with an addition ratio of 0.5 wt% to 10 wt% of the polyolefin elastomer resin;

[0012] The antioxidant includes any one of the following: pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] or tris(2,4-di-tert-butylphenyl) phosphite, added at a ratio of 0.1 wt% to 0.5 wt% of the polyolefin elastomer resin;

[0013] The UV-resistant additives are any one or more of the following combinations: 2-hydroxy-4-octyloxybenzophenone, bis(2,2,6,6-tetramethylpiperidinyl) sebacate, added at a ratio of 0.1wt% to 0.3wt% of the polyolefin elastomer resin;

[0014] The tackifier is γ-methacryloxypropyltrimethoxysilane, and the addition ratio is 0.2wt% to 0.6wt% of the encapsulating film resin.

[0015] Furthermore, the silane coupling agent comprises any one or a mixture of the following: γ-aminopropyltriethoxysilane, γ-(2,3-epoxypropoxy)propyltrimethoxysilane, and γ-methacryloyloxypropyl.

[0016] Furthermore, the internal mixer has a temperature of 120°C, a rotation speed of 20 r / min, and a mixing time of 15 min; the single-screw extruder has a melt extrusion granulation temperature of 120–130°C.

[0017] Furthermore, the accelerating voltage of the electron accelerator described in S3 is 1 to 4.5 MeV, the electron beam irradiation dose is 50 to 200 kGy, and the irradiation atmosphere includes any one of the following: nitrogen atmosphere, vacuum atmosphere, or air atmosphere.

[0018] Furthermore, the mass ratio of polyolefin elastomer resin and polyolefin elastomer graft to continuous fiber in S2 is 70-50:30-50.

[0019] On the other hand, the present invention also provides an impact-resistant photovoltaic encapsulating film, which is prepared using the above-described preparation method.

[0020] On the other hand, the present invention also provides a photovoltaic module, the photovoltaic module comprising a photovoltaic module layer structure, the photovoltaic module layer structure comprising a front panel laminated together, a first impact-resistant photovoltaic encapsulating film, a solar cell, a second impact-resistant photovoltaic encapsulating film, and a back panel; the first impact-resistant photovoltaic encapsulating film and the second impact-resistant photovoltaic encapsulating film are both prepared using the above-described preparation method.

[0021] Compared with existing technical solutions, the above technical solutions conceived in this invention are as follows:

[0022] This invention utilizes continuous fibers, such as glass fiber, carbon fiber, and aramid fiber, to enhance the rigidity and impact resistance of POE resin. The process involves melt-extruding POE resin and POE grafts to form a resin melt, which is then injected into an impregnation mold and melt-impregnated with continuous fibers treated with a silane coupling agent. After cooling, a unidirectional prepreg tape is formed, which is then laminated into multiple layers to form a base film. Electron beam irradiation post-treatment technology induces a cross-linking reaction, resulting in a fiber-reinforced impact-resistant photovoltaic encapsulating film. The continuous fibers, surface-treated with a silane coupling agent, can chemically react with the maleic anhydride or glycidyl methacrylate groups grafted onto POE, thus exhibiting excellent interfacial compatibility. By combining continuous fiber melt impregnation technology with electron beam irradiation post-treatment technology, the prepared photovoltaic encapsulating film significantly improves the material's impact resistance while maintaining good encapsulation performance, making it widely applicable in the field of lightweight flexible photovoltaic modules! Attached Figure Description

[0023] Figure 1 This is a schematic diagram illustrating a method for preparing an impact-resistant photovoltaic encapsulating film in one embodiment of the present invention. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments.

[0025] A method for preparing an impact-resistant photovoltaic encapsulating film includes the following steps:

[0026] S1. The dried polyolefin elastomer resin, polyolefin elastomer graft, crosslinking agent, tackifier, antioxidant and UV stabilizer are mixed in an internal mixer and then placed in a single screw extruder for melt extrusion granulation to obtain a special material for polyolefin elastomer hot melt adhesive.

[0027] S2. The polyolefin elastomer hot melt adhesive material is placed in a twin-screw extruder and melted to form a resin melt. The resin melt is then injected into an impregnation mold and impregnated with continuous fibers treated with silane coupling agent that have been stretched by traction. After cooling, a unidirectional prepreg tape is obtained, and after multi-layer lamination, a photovoltaic encapsulation base film is obtained.

[0028] S3. The photovoltaic encapsulation base film is placed under an electron accelerator for electron beam irradiation crosslinking and curing to prepare the impact-resistant photovoltaic encapsulation film.

[0029] Further, before S1, the polyolefin elastomer resin is placed in a forced-air drying oven and dried at 60-80°C for 12-24 hours, and then cooled to room temperature with cold air to obtain a dried polyolefin elastomer, wherein the melt index of the polyolefin elastomer resin is 20-30 g / 10 min.

[0030] Further, the polyolefin elastomer graft described in S1 includes any one of the following: polyolefin elastomer grafted with maleic anhydride or polyolefin elastomer grafted with glycidyl methacrylate, with an addition ratio of 5wt% to 10wt% of the polyolefin elastomer resin.

[0031] Further, the crosslinking agent comprises any one or any combination of the following: triallyl isocyanurate, trimethylolpropane trimethacrylate, and triallyl cyanurate, with an addition ratio of 0.5 wt% to 10 wt% of the polyolefin elastomer resin;

[0032] The antioxidant includes any one of the following: pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] or tris(2,4-di-tert-butylphenyl) phosphite, added at a ratio of 0.1 wt% to 0.5 wt% of the polyolefin elastomer resin;

[0033] The UV-resistant additives are any one or more of the following combinations: 2-hydroxy-4-octyloxybenzophenone, bis(2,2,6,6-tetramethylpiperidinyl) sebacate, added at a ratio of 0.1wt% to 0.3wt% of the polyolefin elastomer resin;

[0034] The tackifier is γ-methacryloxypropyltrimethoxysilane, and the addition ratio is 0.2wt% to 0.6wt% of the encapsulating film resin.

[0035] Furthermore, the silane coupling agent comprises any one or a mixture of the following: γ-aminopropyltriethoxysilane, γ-(2,3-epoxypropoxy)propyltrimethoxysilane, and γ-methacryloyloxypropyl.

[0036] Furthermore, the internal mixer has a temperature of 120°C, a rotation speed of 20 r / min, and a mixing time of 15 min; the single-screw extruder has a melt extrusion granulation temperature of 120–130°C.

[0037] Furthermore, the accelerating voltage of the electron accelerator described in S3 is 1 to 4.5 MeV, the electron beam irradiation dose is 50 to 200 kGy, and the irradiation atmosphere includes any one of the following: nitrogen atmosphere, vacuum atmosphere, or air atmosphere.

[0038] Furthermore, the mass ratio of polyolefin elastomer resin and polyolefin elastomer graft to continuous fiber in S2 is 70-50:30-50.

[0039] On the other hand, the present invention also provides an impact-resistant photovoltaic encapsulating film, which is prepared using the above-described preparation method.

[0040] On the other hand, the present invention also provides a photovoltaic module, the photovoltaic module comprising a photovoltaic module layer structure, the photovoltaic module layer structure comprising a front panel laminated together, a first impact-resistant photovoltaic encapsulating film, a solar cell, a second impact-resistant photovoltaic encapsulating film, and a back panel; the first impact-resistant photovoltaic encapsulating film and the second impact-resistant photovoltaic encapsulating film are both prepared using the above-described preparation method.

[0041] Compared with existing technical solutions, the above technical solutions conceived in this invention are as follows:

[0042] This invention utilizes continuous fibers, such as glass fiber, carbon fiber, and aramid fiber, to enhance the rigidity and impact resistance of POE resin. The process involves melt-extruding POE resin and POE grafts to form a resin melt, which is then injected into an impregnation mold and melt-impregnated with continuous fibers treated with a silane coupling agent. After cooling, a unidirectional prepreg tape is formed, which is then laminated into multiple layers to form a base film. Electron beam irradiation post-treatment technology induces a cross-linking reaction, resulting in a fiber-reinforced impact-resistant photovoltaic encapsulating film. The continuous fibers, surface-treated with a silane coupling agent, can chemically react with the maleic anhydride or glycidyl methacrylate groups grafted onto POE, thus exhibiting excellent interfacial compatibility. By combining continuous fiber melt impregnation technology with electron beam irradiation post-treatment technology, the prepared photovoltaic encapsulating film significantly improves the material's impact resistance while maintaining good encapsulation performance, making it widely applicable in the field of lightweight flexible photovoltaic modules!

[0043] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments.

[0044] Example 1:

[0045] A method for preparing an impact-resistant photovoltaic encapsulating film, comprising the following steps:

[0046] (1) Dry polyolefin elastomer (POE) resin, POE-grafted maleic anhydride (POE-g-MAH), triallyl isocyanurate (TAIC), γ-methacryloyloxypropyltrimethoxysilane, pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], 2-hydroxy-4-octyloxybenzophenone, and bis(2,2,6,6-tetramethylpiperidinyl)sebacate were mixed evenly in a mixer and then melt-extruded and granulated by a single screw to obtain a special material for POE hot melt adhesive. Among them, POE-g-MAH resin The proportions of ester added were 10 wt% of POE resin, triallyl isocyanurate added 6 wt% of POE resin, γ-methacryloxypropyltrimethoxysilane added 0.3 wt% of POE resin, pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] added 0.2 wt% of POE resin, and 2-hydroxy-4-octyloxybenzophenone and bis(2,2,6,6-tetramethylpiperidinyl)sepiacetate added 0.1 wt% of POE resin. The internal mixer temperature was 120℃, the rotation speed was 20 r / min, and the mixing time was 15 min.

[0047] The single-screw granulation temperature is 120–130℃;

[0048] (2) The POE hot melt adhesive material obtained in step (1) is extruded through a twin-screw extruder to form a resin melt. The temperature of the twin-screw extruder is 120-130℃. Then, the resin melt is injected into an impregnation mold and impregnated and compounded with continuous glass fibers treated with γ-aminopropyltriethoxysilane coupling agent through traction unfolding. After cooling, a unidirectional prepreg tape is obtained. The three unidirectional prepreg tapes are compounded by a steel strip compounding machine at a stacking angle of 0° / 90° / 0°. After cooling, the tapes are wound up to obtain a base film with a thickness of 0.45mm.

[0049] (3) The photovoltaic encapsulation base film obtained in step (2) is placed under a 1MeV electron accelerator for electron beam irradiation crosslinking and curing to prepare the fiber-reinforced impact-resistant photovoltaic encapsulation film. The electron beam irradiation is carried out in a nitrogen atmosphere with an irradiation dose of 150kGy.

[0050] Example 2:

[0051] A method for preparing an impact-resistant photovoltaic encapsulating film, comprising the following steps:

[0052] (1) Dry polyolefin elastomer (POE) resin, POE-grafted maleic anhydride (POE-g-MAH), trimethylolpropane trimethacrylate (TMPTMA), γ-methacryloyloxypropyltrimethoxysilane, pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], 2-hydroxy-4-octyloxybenzophenone, and bis(2,2,6,6-tetramethylpiperidinyl)sebacate were mixed evenly in a mixer and then melt-extruded and granulated by a single screw to obtain a special material for POE hot melt adhesive. Among them, POE-g-MAH... The addition ratio of AH resin is 5 wt% of POE resin, trimethylolpropane trimethacrylate is 10 wt% of POE resin, γ-methacryloyloxypropyltrimethoxysilane is 0.2 wt% of POE resin, pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] is 0.5 wt% of POE resin, and 2-hydroxy-4-octyloxybenzophenone and bis(2,2,6,6-tetramethylpiperidinyl)sepiacetate are 0.3 wt% of POE resin. The internal mixer temperature is 120℃, the speed is 20 r / min, and the mixing time is 15 min. The single-screw granulation temperature is 120~130℃.

[0053] (2) The POE hot melt adhesive material obtained in step (1) is melt-extruded to form a resin melt. The temperature of the twin-screw extruder is 120-130℃. Then the resin melt is injected into the impregnation mold and impregnated and composited with continuous carbon fibers treated with γ-(2,3-epoxypropoxy)propyltrimethoxysilane coupling agent through traction unfolding. After cooling, a unidirectional prepreg tape is obtained. The three unidirectional prepreg tapes are composited with a steel strip composite machine at a stacking angle of 0° / 90° / 0°. After cooling, the tapes are wound up to obtain a base film with a thickness of 0.4 mm.

[0054] (3) The photovoltaic encapsulation base film obtained in step (2) is placed under a 4.5MeV electron accelerator for electron beam irradiation crosslinking and curing to prepare the fiber-reinforced impact-resistant photovoltaic encapsulation film. The electron beam irradiation is carried out in a vacuum atmosphere and the irradiation dose is 50kGy.

[0055] Example 3:

[0056] A method for preparing an impact-resistant photovoltaic encapsulating film, comprising the following steps:

[0057] (1) Dry polyolefin elastomer (POE) resin, POE-grafted glycidyl methacrylate (POE-g-GMA), triallyl isocyanurate, γ-methacryloyloxypropyltrimethoxysilane, pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], 2-hydroxy-4-octyloxybenzophenone, and bis(2,2,6,6-tetramethylpiperidinyl) sebacate were mixed evenly in a mixer and then melt-extruded and granulated by a single screw to obtain a special material for POE hot melt adhesive. Among them, POE-g-GMA resin The addition ratio of the following components is 10 wt% of POE resin: triallyl isocyanurate, 0.5 wt% of POE resin, 0.6 wt% of γ-methacryloxypropyltrimethoxysilane, 0.3 wt% of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], and 0.3 wt% of POE resin for 2-hydroxy-4-octyloxybenzophenone and bis(2,2,6,6-tetramethylpiperidinyl)sepiacetate. The internal mixer temperature is 120℃, the speed is 20 r / min, and the mixing time is 15 min. The single-screw granulation temperature is 120–130℃.

[0058] (2) The POE hot melt adhesive material obtained in step (1) is melt-extruded to form a resin melt. The temperature of the twin-screw extruder is 120-130℃. Then the resin melt is injected into the impregnation mold and impregnated and compounded with the continuous aramid fiber treated with γ-methacryloxypropyl coupling agent through traction. After cooling, a unidirectional prepreg tape is obtained. The three unidirectional prepreg tapes are compounded by a steel strip compounding machine at a stacking angle of 0° / 90° / 0°. After cooling, the tapes are wound up to obtain a base film with a thickness of 0.45mm.

[0059] (3) The photovoltaic encapsulation base film obtained in step (2) is placed under a 2MeV electron accelerator for electron beam irradiation crosslinking and curing to prepare the fiber-reinforced impact-resistant photovoltaic encapsulation film. The electron beam irradiation is carried out in an air atmosphere and the irradiation dose is 200kGy.

[0060] Example 4:

[0061] A method for preparing an impact-resistant photovoltaic encapsulating film, comprising the following steps:

[0062] (1) Dry polyolefin elastomer (POE) resin, POE-grafted maleic anhydride (POE-g-MAH), triallyl cyanurate (TAC), γ-methacryloyloxypropyltrimethoxysilane, pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], 2-hydroxy-4-octyloxybenzophenone, and bis(2,2,6,6-tetramethylpiperidinyl)sebacate were mixed evenly in a mixer and then melt-extruded and granulated by a single screw to obtain a special material for POE hot melt adhesive. The POE-g-MAH resin was added... The following additives were used: 5 wt% POE resin, 8 wt% triallyl cyanurate (TAC) cyanurate, 0.2 wt% γ-methacryloxypropyltrimethoxysilane ester, 0.5 wt% pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] ester, and 0.2 wt% 2-hydroxy-4-octyloxybenzophenone and bis(2,2,6,6-tetramethylpiperidinyl) sebacate ester. The internal mixer temperature was 120℃, the speed was 20 r / min, and the mixing time was 15 min.

[0063] The single-screw granulation temperature is 120–130℃;

[0064] (2) The POE hot melt adhesive material obtained in step (1) is melt-extruded to form a resin melt. The temperature of the twin-screw extruder is 120-130℃. The resin melt is then injected into the impregnation mold and impregnated and composited with continuous carbon fibers treated with γ-methacryloxypropyl coupling agent through traction unfolding. After cooling, a unidirectional prepreg tape is obtained. The three unidirectional prepreg tapes are composited with a steel strip composite machine at a stacking angle of 0° / 90° / 0°. After cooling, the tapes are wound up to obtain a base film with a thickness of 0.45mm.

[0065] (3) The photovoltaic encapsulation base film obtained in step (2) is placed under a 2MeV electron accelerator for electron beam irradiation crosslinking and curing to prepare the fiber-reinforced impact-resistant photovoltaic encapsulation film. The electron beam irradiation is carried out in a nitrogen atmosphere with an irradiation dose of 150kGy.

[0066] Example 5:

[0067] A method for preparing an impact-resistant photovoltaic encapsulating film, comprising the following steps:

[0068] (1) Dry polyolefin elastomer (POE) resin, POE-grafted glycidyl methacrylate (POE-g-GMA), triallyl isocyanurate, γ-methacryloyloxypropyltrimethoxysilane, pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], 2-hydroxy-4-octyloxybenzophenone, and bis(2,2,6,6-tetramethylpiperidinyl) sebacate were mixed evenly in a mixer and then melt-extruded and granulated by a single screw to obtain a special material for POE hot melt adhesive. Among them, POE-g-GMA resin The addition ratio of the following components was 8 wt% of POE resin: triallyl isocyanurate, γ-methacryloxypropyltrimethoxysilane, pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], 0.2 wt% of POE resin, and 0.1 wt% of 2-hydroxy-4-octyloxybenzophenone and bis(2,2,6,6-tetramethylpiperidinyl)sepiacetate. The internal mixer temperature was 120℃, the rotation speed was 20 r / min, and the mixing time was 15 min.

[0069] The single-screw granulation temperature is 120–130℃;

[0070] (2) The POE hot melt adhesive material obtained in step (1) is melt-extruded to form a resin melt. The temperature of the twin-screw extruder is 120-130℃. The resin melt is then injected into the impregnation mold and impregnated and compounded with continuous glass fibers treated with γ-aminopropyltriethoxysilane coupling agent through traction. After cooling, a unidirectional prepreg tape is obtained. The three unidirectional prepreg tapes are compounded at a stacking angle of 0° / 90° / 0° using a steel strip compounding machine. After cooling, the tapes are wound up to obtain a base film with a thickness of 0.40 mm.

[0071] (3) The photovoltaic encapsulation base film obtained in step (2) is placed under a 1MeV electron accelerator for electron beam irradiation crosslinking and curing to prepare the fiber-reinforced impact-resistant photovoltaic encapsulation film. The electron beam irradiation is carried out in a nitrogen atmosphere with an irradiation dose of 150kGy.

[0072] Example 6:

[0073] A method for preparing an impact-resistant photovoltaic encapsulating film, comprising the following steps:

[0074] (1) Dry polyolefin elastomer (POE) resin, POE-grafted glycidyl acrylate (POE-g-GMA), trimethylolpropane trimethacrylate (TMPTMA), γ-methacryloyloxypropyltrimethoxysilane, pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], 2-hydroxy-4-octyloxybenzophenone, and bis(2,2,6,6-tetramethylpiperidinyl) sebacate were mixed evenly in a mixer and then melt-extruded and granulated by a single screw to obtain a special material for POE hot melt adhesive. Among them, POE-g-MAH resin The addition ratio of the following components was 10 wt% of POE resin: trimethylolpropane trimethacrylate (TMPTMA), γ-methacryloyloxypropyltrimethoxysilane, pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], 0.2 wt% of POE resin, and 0.1 wt% of 2-hydroxy-4-octyloxybenzophenone and bis(2,2,6,6-tetramethylpiperidinyl) sebacate. The internal mixer temperature was 120℃, the speed was 20 r / min, and the mixing time was 15 min. The single-screw granulation temperature was 120–130℃.

[0075] (2) The POE hot melt adhesive material obtained in step (1) is melt-extruded to form a resin melt. The temperature of the twin-screw extruder is 120-130℃. Then the resin melt is injected into the impregnation mold and impregnated and compounded with the continuous aramid fiber treated with γ-(2,3-epoxypropoxy)propyltrimethoxysilane coupling agent through traction. After cooling, a unidirectional prepreg tape is obtained. The three unidirectional prepreg tapes are compounded by a steel strip compounding machine at a stacking angle of 0° / 90° / 0°. After cooling, the tapes are wound up to obtain a base film with a thickness of 0.40 mm.

[0076] (3) The photovoltaic encapsulation base film obtained in step (2) is placed under a 1MeV electron accelerator for electron beam irradiation crosslinking and curing to prepare the fiber-reinforced impact-resistant photovoltaic encapsulation film. The electron beam irradiation is carried out in a nitrogen atmosphere with an irradiation dose of 200kGy.

[0077] The following are two comparative examples:

[0078] Comparative Example 1: EVA film was used as the encapsulation material, without adding an impact-resistant layer.

[0079] Comparative Example 2: POE film was used as the encapsulation material, without adding an impact-resistant layer.

[0080] Fabrication of lightweight flexible photovoltaic modules: A white or black backsheet, a back sealing film, a cell layer, a front sealing film, and a transparent front panel are stacked sequentially from bottom to top and then laminated together using a laminator. The difference is that in this embodiment of the invention, the back sealing film and the front sealing film are replaced with a self-made glass fiber reinforced EVA composite film. In Comparative Example 1, the back and front sealing films are both EVA films without the addition of an impact-resistant layer. In Comparative Example 2, the back and front sealing films are both POE films without the addition of an impact-resistant layer.

[0081] Impact resistance test: A standard ice ball with a diameter of 25mm and a mass of 7.53g is launched at a speed of 23.0m / s and impacts 11 locations on the encapsulated photovoltaic module. The impact resistance of the photovoltaic module is judged based on three aspects: appearance, maximum power attenuation, and insulation resistance.

[0082] The test results are shown in Table 1:

[0083] Table 1

[0084]

[0085] The weight of the encapsulation structure mentioned in this invention refers to the weight per square meter of the encapsulation material used in photovoltaic modules. The weather resistance test refers to testing the impact-resistant photovoltaic encapsulation film, EVA film, and POE film prepared according to the IEC61215 and IEC61730 weather resistance test standards. As can be seen from the table, the impact-resistant photovoltaic encapsulation film prepared according to the embodiments of this invention showed no obvious defects in appearance after the impact test, power attenuation ≤5%, and insulation resistance ≥40MΩ. . m 2 Furthermore, the impact-resistant photovoltaic encapsulating film prepared by this invention is inexpensive, has no storage cycle issues, and can replace epoxy fiberglass prepreg for widespread application in the field of lightweight modules!

[0086] 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 an impact-resistant photovoltaic encapsulating film, characterized in that, Includes the following steps: S1. Dry polyolefin elastomer resin, polyolefin elastomer graft, crosslinking agent, tackifier, antioxidant and UV stabilizer are mixed in an internal mixer and then placed in a single screw extruder for melt extrusion granulation to obtain a special material for polyolefin elastomer hot melt adhesive. S2. The polyolefin elastomer hot melt adhesive material is placed in a twin-screw extruder and melted to form a resin melt. The resin melt is then injected into an impregnation mold and impregnated with continuous fibers treated with silane coupling agent that have been stretched by traction. After cooling, a unidirectional prepreg tape is obtained, and after multi-layer lamination, a photovoltaic encapsulation base film is obtained. S3. The photovoltaic encapsulation base film is placed under an electron accelerator for electron beam irradiation crosslinking and curing to prepare the impact-resistant photovoltaic encapsulation film; The accelerating voltage of the electron accelerator in S3 is 1 to 4.5 MeV; the electron beam irradiation dose is 50 to 200 kGy; and the irradiation atmosphere includes any one of the following: nitrogen atmosphere, vacuum atmosphere, or air atmosphere. The mass ratio of polyolefin elastomer resin and polyolefin elastomer graft to continuous fiber in S2 is 70-50:30-50.

2. The method for preparing the impact-resistant photovoltaic encapsulating film as described in claim 1, characterized in that, Before S1, the polyolefin elastomer resin is placed in a forced-air drying oven and dried at 60-80°C for 12-24 hours, and then cooled to room temperature with cold air to obtain the dried polyolefin elastomer. The melt index of the polyolefin elastomer resin is 20-30 g / 10 min.

3. The method for preparing the impact-resistant photovoltaic encapsulating film as described in claim 1, characterized in that, The polyolefin elastomer graft in S1 includes any one of the following: polyolefin elastomer grafted with maleic anhydride or polyolefin elastomer grafted with glycidyl methacrylate, with an addition ratio of 5wt% to 10wt% of the polyolefin elastomer resin.

4. The method for preparing the impact-resistant photovoltaic encapsulating film as described in claim 1, characterized in that, The crosslinking agent includes any one or any combination of the following: triallyl isocyanurate, trimethylolpropane trimethacrylate, and triallyl cyanurate, with an addition ratio of 0.5 wt% to 10 wt% of the polyolefin elastomer resin. The antioxidant includes any one of the following: pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] or tris(2,4-di-tert-butylphenyl) phosphite, added at a ratio of 0.1 wt% to 0.5 wt% of the polyolefin elastomer resin; The UV-resistant additives are any one or more of the following combinations: 2-hydroxy-4-octyloxybenzophenone, bis(2,2,6,6-tetramethylpiperidinyl) sebacate, added at a ratio of 0.1wt% to 0.3wt% of the polyolefin elastomer resin; The tackifier is γ-methacryloxypropyltrimethoxysilane, and the addition ratio is 0.2wt% to 0.6wt% of the encapsulating film resin.

5. The method for preparing the impact-resistant photovoltaic encapsulating film as described in claim 1, characterized in that, The silane coupling agent includes any one or a mixture of the following: γ-aminopropyltriethoxysilane, γ-(2,3-epoxypropoxy)propyltrimethoxysilane, and γ-methacryloxypropyl.

6. The method for preparing the impact-resistant photovoltaic encapsulating film as described in claim 1, characterized in that, The internal mixer has a temperature of 120℃, a rotation speed of 20r / min, and a mixing time of 15min; the single-screw extruder has a melt extrusion granulation temperature of 120~130℃.

7. An impact-resistant photovoltaic encapsulating film, characterized in that, It is prepared using the preparation method described in any one of claims 1 to 6.

8. A photovoltaic module, characterized in that, The photovoltaic module includes a photovoltaic module layer structure, which includes a front panel laminated together, a first impact-resistant photovoltaic encapsulating film, a solar cell, a second impact-resistant photovoltaic encapsulating film, and a back panel; the first impact-resistant photovoltaic encapsulating film and the second impact-resistant photovoltaic encapsulating film are both prepared using the preparation method described in any one of claims 1 to 6.

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