High-reflection encapsulant film for back contact cell module and preparation method thereof and photovoltaic module

Abstract

This invention relates to the field of photovoltaic technology, and in particular to a high-reflectivity encapsulating film for grid-free solar cell modules, its preparation method, and a photovoltaic module thereof. The high-reflectivity encapsulating film for grid-free solar cell modules includes a carrier layer, a light transfer layer, and an infrared reflective layer; the carrier layer comprises 50-80 parts of TPO resin, 20-50 parts of POE resin, and Eu... 3+ Modified organic phototransfer powder (0.05-0.5 parts) and additives; the phototransfer layer includes 100 parts EVA resin and Eu... 3+ Modified organic photoconversion powder (0.05-0.5 parts) and additives; the infrared reflective layer includes 100 parts POE resin and Eu... 3+ The mixture comprises 0.05–0.5 parts of modified organic light-converting powder, 0.5–10 parts of rare earth manganese oxide, and additives. The high-reflectivity encapsulating film of this invention can be used in gridless cell modules, balancing the effects of low-temperature solder ribbon bonding, red light reflection, module power generation temperature, and module power.

Description

Technical Field

[0001] This invention relates to the field of photovoltaic technology, and in particular to a high-reflectivity encapsulating film for gridless solar cell modules, its preparation method, and a photovoltaic module thereof. Background Technology

[0002] Encapsulating films for busbarless solar modules are mainly used in HJT cells. Existing encapsulating films for busbarless solar modules are primarily transparent cut-off type, EE / EP / EPE pre-crosslinked type, or composite integrated films. For modules, the use of infrared-reflective black encapsulating films can further improve module power, reduce module power generation temperature, increase power generation efficiency, and achieve energy savings.

[0003] However, there is currently no suitable infrared-reflective black encapsulating film for grid-less solar modules. This is because existing infrared-reflective black encapsulating films have high fluidity at high temperatures, making them unable to press and fix the low-temperature solder wires of grid-less modules, resulting in problems such as incomplete connections and solder wire misalignment. Providing a high-reflectivity encapsulating film suitable for grid-less solar modules would be of great significance for improving the power output of grid-less solar modules.

[0004] In view of this, the present invention is hereby proposed. Summary of the Invention

[0005] One object of the present invention is to provide a high-reflectivity encapsulating film for gridless battery modules, which can improve the power of the module and reduce the PID degradation of the module.

[0006] Another object of the present invention is to provide a method for preparing a high-reflectivity encapsulating film for gridless battery modules.

[0007] Another object of the present invention is to provide a photovoltaic module.

[0008] To achieve the above-mentioned objectives of the present invention, one aspect of the present invention provides a high-reflectivity encapsulating film for gridless battery modules, comprising a carrier layer, a light transfer layer and an infrared reflective layer stacked sequentially;

[0009] The supporting layer is mainly composed of the following components in parts by weight: 50-80 parts TPO resin, 20-50 parts POE resin, and Eu... 3+ 0.05–0.5 parts of modified organic photoconversion powder and 0.42–4.7 parts of the first additive;

[0010] The phototransfer layer is mainly composed of the following components in parts by weight: 100 parts EVA resin, Eu 3+ 0.05–0.5 parts of modified organic photoconversion powder and 0.42–4.7 parts of second additive;

[0011] The infrared reflective layer is mainly composed of the following components in parts by weight: 100 parts POE resin, Eu 3+ 0.05–0.5 parts of modified organic photoconversion powder, 0.5–10 parts of rare earth manganese oxide, and 0.42–4.7 parts of third auxiliary agent;

[0012] Wherein, Eu 3+ The modified organic photoconversion powder is mainly prepared from the following components by weight: 100 parts of benzotriazole photoconversion powder, 1-10 parts of benzotriazole UV absorber, and Eu. 3+ The mixture consists of 1-10 parts of doped CdS quantum dot powder, 0.1-5 parts of silane coupling agent, 0.1-10 parts of silicate ester, 0.1-1 parts of hydrolysate, and 5-20 parts of solvent.

[0013] In a specific embodiment of the present invention, the benzotriazole photoconverter includes at least one of the compounds represented by the structures of formulas I to II:

[0014]

[0015]

[0016] In a specific embodiment of the present invention, the rare earth manganese oxide is YMnO3.

[0017] In a specific embodiment of the present invention, the Eu 3+ The preparation of CdS quantum dot powder includes: (a) mixing and dissolving water-soluble Cd salt, acrylamide and initiator in water to obtain an aqueous phase; dissolving a nonionic surfactant in an organic solvent to obtain an oil phase; adding the aqueous phase to the oil phase, stirring and pre-emulsifying, and then reacting at 60-80°C for 2-6 hours under a protective atmosphere to obtain a Cd salt-PAM emulsion;

[0018] (b) A solution containing sodium sulfide and acrylamide is added to the Cd salt-PAM emulsion and reacted at 60–80°C for 2–4 hours. Then, an aqueous solution containing water-soluble Eu salt is added and reacted at 60–80°C for 1–3 hours to obtain Eu. 3+ Doped CdS-PAM composite emulsion;

[0019] (c) The Eu 3+ After hydrothermal reaction, the doped CdS-PAM nanoemulsion was collected and dried to obtain the Eu. 3+ CdS-doped quantum dot powder.

[0020] In a specific embodiment of the present invention, the water-soluble Cd salt includes CdSO4·8 / 3H2O.

[0021] In a specific embodiment of the present invention, in step (a), the mass ratio of the water-soluble Cd salt to the acrylamide is 1:(15-25). Further, the initiator is ammonium persulfate; the mass of the initiator is 1 wt% to 10 wt% of the mass of the acrylamide.

[0022] In a specific embodiment of the present invention, the nonionic surfactant comprises Span 80; the organic solvent comprises cyclohexane. Further, the mass ratio of the nonionic surfactant to the organic solvent is 1:(20-30).

[0023] In a specific embodiment of the present invention, the mass ratio of sodium sulfide to acrylamide in the solution containing sodium sulfide and acrylamide is 1:(2-4).

[0024] In a specific embodiment of the present invention, the solution containing sodium sulfide and acrylamide is an aqueous solution or an emulsion. Further, in the aqueous solution, the mass ratio of acrylamide to water is 1:(5-8).

[0025] In a specific embodiment of the present invention, the emulsion further includes a nonionic surfactant and an organic solvent. Further, the nonionic surfactant includes Span 80, and the organic solvent includes cyclohexane.

[0026] In a specific embodiment of the present invention, in step (b), the mass ratio of the solution containing sodium sulfide and acrylamide to the Cd salt-PAM emulsion is 1:(2-20).

[0027] In a specific embodiment of the present invention, in step (b), the amount of water-soluble Eu salt in the aqueous solution containing water-soluble Eu salt is 0.5 to 15 times that of acrylamide in step (a).

[0028] In a specific embodiment of the present invention, the benzotriazole ultraviolet absorber includes UV-329.

[0029] In a specific embodiment of the present invention, the Eu 3+ The preparation of modified organic phototransfer powder includes: mixing the benzotriazole phototransfer powder, the benzotriazole UV absorber, and the Eu... 3+ CdS quantum doped powder was dispersed in a solvent, and a silane coupling agent, silicate ester, and hydrolysate were added. After hydrolysis, the solvent was removed and the mixture was dried to obtain the Eu. 3+ Modified organic phototransfer powder.

[0030] In a specific embodiment of the present invention, the thickness ratio of the carrier layer, the light conversion layer and the infrared reflective layer is 1:(1.5~2.5):(1.5~2.5).

[0031] In a specific embodiment of the present invention, the thickness of the carrier layer is 0.05-0.2 mm; the thickness of the light conversion layer is 0.1-0.3 mm; and the thickness of the infrared reflective layer is 0.1-0.3 mm.

[0032] The present invention also provides a method for preparing the high-reflectivity encapsulating film for gridless battery modules as described above, comprising the following steps:

[0033] The carrier layer, light transfer layer and infrared reflective layer are co-extruded, stretched and pulled according to the raw material ratio, and then one side of the carrier layer is subjected to electron beam irradiation pre-crosslinking treatment to obtain the high reflective encapsulation film.

[0034] In a specific embodiment of the present invention, the degree of pre-crosslinking in the electron beam irradiation pre-crosslinking treatment is 1% to 60%.

[0035] In another aspect, the present invention provides a photovoltaic module, including any of the above-described high-reflectivity encapsulating films for gridless cell modules.

[0036] In a specific embodiment of the present invention, the photovoltaic module further includes a solar cell and glass; the carrier layer in the encapsulating film is attached to the solar cell, and the infrared reflective layer in the encapsulating film is attached to the glass.

[0037] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0038] (1) This invention employs a three-layer structure, where the supporting layer provides a better pressing effect on the low-temperature solder strip; the infrared reflective layer utilizes rare earth manganese oxide in conjunction with Eu... 3+ Modified organic light-converting powder utilizes the high refractive index of rare earth manganese oxides to improve the infrared reflectivity of the infrared reflective layer, thereby providing heat insulation and reducing the power generation temperature of the module. Furthermore, it utilizes Eu... 3+ Modified organic light-converting powder converts transmitted ultraviolet light into red light; the light-converting layer in the middle can convert some of the ultraviolet light passing through the light-converting layer into red light, which is then reflected onto the solar cell by the infrared reflective layer, thus achieving a certain degree of power gain.

[0039] (2) The gridless battery module made by using the high reflectivity encapsulation film of the present invention can simultaneously improve the bonding effect of low temperature solder ribbon, enhance the reflection effect of red light, reduce the power generation temperature of the module, and increase the power of the module. Detailed Implementation

[0040] The technical solution of the present invention will be clearly and completely described below with reference to 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.

[0041] In the description of this invention, it should be noted that the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0042] The present invention provides a high-reflectivity encapsulating film for gridless battery modules, comprising a carrier layer, a light transfer layer and an infrared reflective layer stacked sequentially;

[0043] The support layer is mainly composed of the following components by weight: 50-80 parts TPO resin, 20-50 parts POE resin, and Eu... 3+ 0.05–0.5 parts of modified organic photoconversion powder and 0.42–4.7 parts of the first additive;

[0044] The phototransfer layer is mainly composed of the following components in parts by weight: 100 parts EVA resin, Eu... 3+ 0.05–0.5 parts of modified organic photoconversion powder and 0.42–4.7 parts of second additive;

[0045] The infrared reflective layer is mainly composed of the following components in parts by weight: 100 parts POE resin, Eu... 3+ 0.05–0.5 parts of modified organic photoconversion powder, 0.5–10 parts of rare earth manganese oxide, and 0.42–4.7 parts of third auxiliary agent;

[0046] Among them, Eu 3+ The modified organic photoconversion powder is mainly prepared from the following components by weight: 100 parts of benzotriazole photoconversion powder, 1-10 parts of benzotriazole UV absorber, and Eu. 3+ The mixture consists of 1-10 parts of doped CdS quantum dot powder, 0.1-5 parts of silane coupling agent, 0.1-10 parts of silicate ester, 0.1-1 parts of hydrolysate, and 5-20 parts of solvent.

[0047] This invention employs a three-layer structure. The supporting layer provides excellent pressing effect on low-temperature solder ribbons; the infrared reflective layer utilizes rare earth manganese oxide in conjunction with Eu... 3+Modified organic phototransfer powder is used, with rare earth manganese oxide and organic phototransfer powder bridged by silane coupling agents, so that it is uniformly dispersed in the matrix resin. On the one hand, the high refractive index of rare earth manganese oxide is used to improve the infrared light reflectivity of the infrared reflective layer, which plays a role in heat insulation and reducing the power generation temperature of the module. On the other hand, Eu... 3+ Modified organic light-converting powder converts transmitted ultraviolet light into red light; the light-converting layer in the middle can convert some of the ultraviolet light passing through the light-converting layer into red light, which is then reflected onto the solar cell by the infrared reflective layer, thus achieving a certain degree of power gain.

[0048] When the high-reflectivity encapsulating film of this invention is used in modules, sunlight diffusely reflected from the ground shines onto the back of the module, i.e., the infrared reflective layer. The infrared light is reflected away, which serves to insulate the module and reduce its power generation temperature. At the same time, the infrared reflective layer effectively blocks water vapor and oxygen from contacting the photoconversion layer, protecting the photoconversion material and extending its service life. On the other hand, sunlight incident from the front of the module can pass through the gaps between the module cells and shine into the back encapsulating film. The infrared light portion can be reflected onto the cells through the infrared reflective layer, providing a certain degree of power gain to the module. The ultraviolet light portion can be converted into red light through the photoconversion layer and then reflected onto the cells through the infrared reflective layer, which can also provide a certain degree of power gain to the module.

[0049] Eu 3+ In the modified organic phototransfer powder, compared to 100 parts of benzotriazole phototransfer powder, the amounts of the remaining components can be as follows:

[0050] The dosage of benzotriazole UV absorbers can be 1 part, 2 parts, 5 parts, 8 parts, 10 parts, or any combination thereof;

[0051] Eu 3+ The amount of CdS quantum dot powder used can be 1 part, 2 parts, 5 parts, 8 parts, 10 parts, or any combination thereof;

[0052] The amount of silane coupling agent can be 0.1 parts, 1 part, 2 parts, 3 parts, 4 parts, 5 parts, or any combination thereof;

[0053] The amount of silicate can be 1 part, 2 parts, 5 parts, 8 parts, 10 parts, or any combination thereof;

[0054] The amount of hydrolysate can be 0.1 parts, 0.2 parts, 0.5 parts, 0.8 parts, 1 part, or any combination thereof;

[0055] The amount of solvent used can be 5 parts, 8 parts, 10 parts, 12 parts, 15 parts, 18 parts, 20 parts, or any combination thereof.

[0056] In different implementations, the amounts of each component in the support layer, by weight, can be as follows:

[0057] The amount of TPO resin can be 50 parts, 55 parts, 60 parts, 65 parts, 70 parts, 75 parts, 80 parts, or any combination thereof.

[0058] The amount of POE resin can be 20 parts, 25 parts, 30 parts, 35 parts, 40 parts, 45 parts, 50 parts, or any combination thereof.

[0059] Eu 3+ The amount of modified organic photoconversion powder can be 0.05 parts, 0.1 parts, 0.2 parts, 0.3 parts, 0.4 parts, 0.5 parts, or any combination thereof;

[0060] The dosage of the first adjuvant can be 0.42 parts, 0.5 parts, 1 part, 1.5 parts, 2 parts, 3 parts, 4 parts, 4.5 parts, 4.7 parts, or any combination thereof.

[0061] In the carrier layer of this invention, TPO resin is used as the main resin. After subsequent electron beam irradiation pre-crosslinking treatment, it can also achieve a good pressing effect on low-temperature solder ribbons.

[0062] In different embodiments, the amounts of the remaining components in the phototransfer layer, by weight, relative to 100 parts of EVA resin, can be as follows:

[0063] Eu 3+ The amount of modified organic photoconversion powder can be 0.05 parts, 0.1 parts, 0.2 parts, 0.3 parts, 0.4 parts, 0.5 parts, or any combination thereof;

[0064] The dosage of the second adjuvant can be 0.42 parts, 0.5 parts, 1 part, 1.5 parts, 2 parts, 3 parts, 4 parts, 4.5 parts, 4.7 parts, or any combination thereof.

[0065] In different embodiments, the amounts of the remaining components in the infrared reflective layer, by weight, relative to 100 parts of POE resin, can be as follows:

[0066] Eu 3+ The amount of modified organic photoconversion powder can be 0.05 parts, 0.1 parts, 0.2 parts, 0.3 parts, 0.4 parts, 0.5 parts, or any combination thereof;

[0067] The amount of rare earth manganese oxide can be 0.5 parts, 1 part, 2 parts, 5 parts, 8 parts, 10 parts, or any combination thereof;

[0068] The dosage of the third adjuvant can be 0.42 parts, 0.5 parts, 1 part, 1.5 parts, 2 parts, 3 parts, 4 parts, 4.5 parts, 4.7 parts, or any combination thereof.

[0069] In a specific embodiment of the present invention, the TPO resin includes at least one of ethylene-propylene copolymer, ethylene-butene copolymer, ethylene-octene copolymer, ethylene-hexene copolymer, polyethylene, polypropylene, and ethylene propylene diene monomer (EPDM) rubber.

[0070] In a specific embodiment of the present invention, the benzotriazole photoconverter includes at least one of the compounds represented by the structures of formulas I to II:

[0071]

[0072] The benzotriazole photoconversion powder of the present invention has excellent photoconversion effect.

[0073] In a specific embodiment of the present invention, the rare earth manganese oxide is YMnO3.

[0074] In a specific embodiment of the present invention, Eu 3+ The preparation of CdS quantum dot powder includes:

[0075] (a) Aqueous phase is obtained by mixing and dissolving water-soluble Cd salt, acrylamide and initiator in water; oil phase is obtained by dissolving nonionic surfactant in organic solvent; aqueous phase is added to oil phase, stirred and pre-emulsified, and then reacted at 60-80℃ for 2-6h under protective atmosphere to obtain Cd salt-PAM emulsion.

[0076] (b) A solution containing sodium sulfide and acrylamide is added to a Cd salt-PAM emulsion and reacted at 60–80°C for 2–4 hours. Then, an aqueous solution containing water-soluble Eu salt is added and reacted at 60–80°C for 1–3 hours to obtain Eu. 3+ Doped CdS-PAM composite emulsion;

[0077] (c) Eu 3+ After hydrothermal reaction, the doped CdS-PAM nanoemulsion was collected and dried to obtain Eu. 3+ CdS-doped quantum dot powder.

[0078] In actual operation, during step (a), when the aqueous phase is added to the oil phase, a stirring operation is carried out. The stirring time can be 10 to 20 minutes to complete the pre-emulsification.

[0079] Eu is added to each layer of the present invention. 3+ Modified organic photoconversion powder, polyacrylamide (PAM), is a polymer that can coordinate with metal ions. The nitrogen (N) on the molecular chain segments of PAM can interact with Eu. 3+Metal ions undergo an exchange reaction to form coordination polymers, and then Eu... 3+ The complex will form Eu with benzotriazole photoconverter. 3+ -Benzotriazole ligand polymers, these ligand polymers are based on rare earth Eu 3+ As the luminescent center, its excitation wavelength is 300–350 nm (e.g., 340 nm), and its emission wavelength is 613 nm ± 10 nm. It converts ultraviolet light into red light, without passing through the Eu field. 3+ Modified organic light-converting powders can only convert ultraviolet light into blue light.

[0080] In different embodiments, in step (a), under a protective atmosphere, the reaction can be carried out for 2 hours, 3 hours, 4 hours, 5 hours, 6 hours, or any combination thereof at 60°C, 65°C, 70°C, 75°C, 80°C, or any combination thereof. The reaction temperature can be adjusted according to the initiation temperature of the initiator to ensure initiation and system stability. The reaction time can be adjusted according to the conversion rate of acrylamide in the system to ensure that the conversion rate of acrylamide is ≥99%. The conversion rate of acrylamide can be detected by gas chromatography according to GB / T 12005.5-1989.

[0081] In practice, step (b), the addition of the sodium sulfide and acrylamide solution to the Cd salt-PAM emulsion, can be performed using a micro-injection pump to add the sodium sulfide and acrylamide solution to the Cd salt-PAM emulsion at a constant rate. Similarly, the aqueous solution containing water-soluble Eu salt can also be added to the system at a constant rate using a micro-injection pump. The addition rate can be 10–200 mL / h, such as 10 mL / h, 50 mL / h, 80 mL / h, 100 mL / h, 150 mL / h, 180 mL / h, or 200 mL / h.

[0082] In step (b), after adding the solution containing sodium sulfide and acrylamide to the Cd salt-PAM emulsion, the reaction is carried out under the corresponding temperature conditions and with stirring in a sealed environment for the corresponding time; after adding the aqueous solution containing water-soluble Eu salt, the reaction is carried out under the corresponding temperature conditions and with stirring in a sealed environment for the corresponding time.

[0083] In practice, in step (c), the hydrothermal reaction is carried out in a polytetrafluoroethylene-lined hydrothermal reactor. The reactor containing the reactants is placed in a constant-temperature drying oven, and the reaction is carried out at the appropriate temperature for the appropriate time. After the reaction is complete, the solid can be collected by centrifugation, washed with anhydrous ethanol, and dried in a vacuum drying oven at 50–55°C for at least 10 hours to obtain Eu. 3+ CdS-doped quantum dot powder.

[0084] In a specific embodiment of the present invention, the water-soluble Cd salt includes CdSO4·8 / 3H2O.

[0085] In a specific embodiment of the present invention, in step (a), the mass ratio of water-soluble Cd salt to acrylamide is 1:(15-25). Further, the initiator is ammonium persulfate; the mass of the initiator is 1 wt% to 10 wt% of the mass of acrylamide.

[0086] In different embodiments, in step (a), the mass ratio of the water-soluble Cd salt to acrylamide can be 1:15, 1:18, 1:20, 1:22, 1:25, or any combination thereof; the mass of the initiator can be 1 wt%, 2 wt%, 4 wt%, 5 wt%, 8 wt%, 10 wt% of the mass of acrylamide, or any combination thereof.

[0087] In a specific embodiment of the present invention, in step (a), the mass of water is 2 to 6 times the mass of acrylamide. For example, in different embodiments, the mass of water in the aqueous phase of step (a) can be 2, 3, 4, 5, 6 times, or any combination thereof of the mass of acrylamide.

[0088] In a specific embodiment of the invention, the nonionic surfactant includes Span 80; the organic solvent includes cyclohexane. Further, the mass ratio of the nonionic surfactant to the organic solvent is 1:(20-30). In different embodiments, the mass ratio of the nonionic surfactant to the organic solvent can be 1:20, 1:22, 1:25, 1:28, 1:30, or any combination thereof.

[0089] In a specific embodiment of the present invention, in a solution containing sodium sulfide and acrylamide, the mass ratio of sodium sulfide to acrylamide is 1:(2-4). In different embodiments, the mass ratio of sodium sulfide to acrylamide can be 1:2, 1:2.5, 1:3, 1:3.5, 1:4, or any combination thereof.

[0090] In a specific embodiment of the present invention, the solution containing sodium sulfide and acrylamide is an aqueous solution or an emulsion.

[0091] In practice, when step (b) uses an aqueous solution containing sodium sulfide and acrylamide, the mass ratio of acrylamide to water in the aqueous solution is 1:(5-8). In different embodiments, the mass ratio of acrylamide to water in the aqueous solution can be 1:5, 1:6, 1:7, 1:8, or any combination thereof.

[0092] In a specific embodiment of the present invention, when step (b) uses an emulsion containing sodium sulfide and acrylamide, it further includes a nonionic surfactant and an organic solvent. The nonionic surfactant may include Span 80, and the organic solvent may include cyclohexane.

[0093] In a specific embodiment of the present invention, the mass ratio of nonionic surfactant to acrylamide in the emulsion is 1:(0.5-1). Further, the mass ratio of organic solvent to nonionic surfactant is (20-30):1.

[0094] In different embodiments, the mass ratio of nonionic surfactant to acrylamide in the emulsion containing sodium sulfide and acrylamide can be in the range of 1:0.5, 1:0.6, 1:0.8, 1:1, or any combination thereof; and the mass ratio of organic solvent to nonionic surfactant in the emulsion containing sodium sulfide and acrylamide can be in the range of 20:1, 22:1, 25:1, 28:1, 30:1, or any combination thereof.

[0095] The preparation of an emulsion containing sodium sulfide and acrylamide includes: pouring an aqueous solution containing sodium sulfide and acrylamide into the oil phase, stirring and pre-emulsifying for 10–20 min, and then sonicating for 3–6 min. The oil phase is prepared by dissolving a nonionic surfactant (lipophilic) in an organic solvent.

[0096] In a specific embodiment of the present invention, in step (b), the mass ratio of the solution containing sodium sulfide and acrylamide to the Cd salt-PAM emulsion is 1:(2-20).

[0097] In different embodiments, in step (b), the mass ratio of the solution containing sodium sulfide and acrylamide to the Cd salt-PAM emulsion can be 1:2, 1:5, 1:8, 1:10, 1:12, 1:15, 1:18, 1:20, or any combination thereof.

[0098] In a specific embodiment of the present invention, in step (b), the amount of water-soluble Eu salt in the aqueous solution containing water-soluble Eu salt is 0.5 to 15 times that of acrylamide in step (a).

[0099] In different embodiments, in step (b), the amount of water-soluble Eu salt in the aqueous solution containing the water-soluble Eu salt can be 0.5 times, 2 times, 5 times, 8 times, 10 times, 15 times, or any combination thereof of the mass of acrylamide in step (a).

[0100] In a specific embodiment of the present invention, the temperature of the hydrothermal reaction is 100-105°C, and the time of the hydrothermal reaction is 4-8 hours.

[0101] In a specific embodiment of the present invention, the benzotriazole ultraviolet absorber includes UV-329.

[0102] In a specific embodiment of the present invention, the silane coupling agent includes at least one of a silane coupling agent containing a carbon-carbon double bond and / or a silane coupling agent containing an amino group.

[0103] Among them, the carbon-carbon double bond-containing silane coupling agent includes at least one of 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane and 3-methacryloxypropyltriisopropoxysilane; the amino-containing alkoxysilane includes at least one of 3-aminopropyltrimethoxysilane and 3-aminopropyltriethoxysilane.

[0104] In a specific embodiment of the present invention, the silicate ester includes at least one of methyl orthosilicate, ethyl orthosilicate, and isopropyl orthosilicate.

[0105] In a specific embodiment of the present invention, the hydrolysate comprises water and an alcohol solvent. Further, the alcohol solvent comprises at least one selected from methanol, ethanol, 1-propanol, and 2-propanol. The volume ratio of water to the alcohol solvent can be 1:(0.1 to 1), such as 1:1.

[0106] In a specific embodiment of the present invention, Eu 3+ The preparation of modified organic photoconversion powder includes: benzotriazole photoconversion powder, benzotriazole UV absorber, and Eu... 3+ CdS quantum dot powder is dispersed in a solvent or a solvent is added with a silane coupling agent, silicate ester, and hydrolysate. After hydrolysis, the solvent is removed and the mixture is dried to obtain Eu. 3+ Modified organic phototransfer powder. The hydrolysis reaction can be carried out at 25–70°C.

[0107] Among them, Eu is used to prepare 3+ The solvent for modified organic photoconversion powders may include ethyl acetate and / or carbon tetrachloride.

[0108] In a specific embodiment of the present invention, the first auxiliary agent, the second auxiliary agent, and the third auxiliary agent may each independently comprise the following components in parts by weight:

[0109] The ingredients are: 0.1-1.5 parts silane coupling agent, 0.1-1 parts crosslinking agent, 0.1-1 parts co-crosslinking agent, 0.1-1 parts acrylic monomer, 0.01-0.1 parts light stabilizer and 0.01-0.1 parts antioxidant.

[0110] In different embodiments, the amounts of each component in the first, second, and third auxiliary agents, by weight, can be as follows:

[0111] The amount of silane coupling agent can be 0.1 parts, 0.5 parts, 1 part, 1.2 parts, 1.5 parts, or any combination thereof;

[0112] The amount of crosslinking agent can be 0.1 parts, 0.2 parts, 0.5 parts, 0.8 parts, 1 part, or any combination thereof;

[0113] 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;

[0114] The amount of acrylic monomer used can be 0.1 parts, 0.2 parts, 0.5 parts, 0.8 parts, 1 part, or any combination thereof;

[0115] The amount of light stabilizer can be 0.01 parts, 0.02 parts, 0.05 parts, 0.08 parts, 0.1 parts, or any combination thereof;

[0116] The amount of antioxidant can be 0.01 parts, 0.02 parts, 0.05 parts, 0.08 parts, 0.1 parts, or any combination thereof.

[0117] The silane coupling agent includes, but is not limited to, at least one of vinyltriethoxysilane, vinyltrimethoxysilane, vinyltri(β-methoxyethoxy)silane, γ-methacryloxypropyltrimethoxysilane, and vinyltri(β-methoxyethoxy)silane; the crosslinking agent includes, but is not limited to, at least one of peroxide crosslinking agents; the co-crosslinking agent includes, but is not limited to, at least one of triallyl isocyanurate, triallyl cyanurate, trimethylolpropane trimethacrylate, and trimethylolpropane triacrylate; the antioxidant includes, but is not limited to, at least one of hindered phenolic antioxidants; and the light stabilizer includes, but is not limited to, at least one of hindered amine light stabilizers.

[0118] In a specific embodiment of the present invention, the thickness ratio of the carrier layer, the light transfer layer and the infrared reflective layer is 1:(1.5~2.5):(1.5~2.5).

[0119] In different embodiments, the thickness ratio of the carrier layer to the optical transfer layer can be 1:1.5, 1:1.8, 1:2, 1:2.2, 1:2.5, or any combination thereof; the thickness ratio of the carrier layer to the infrared reflective layer can be 1:1.5, 1:1.8, 1:2, 1:2.2, 1:2.5, or any combination thereof.

[0120] In a specific embodiment of the present invention, the thickness of the carrier layer is 0.05-0.2 mm; the thickness of the light transfer layer is 0.1-0.3 mm; and the thickness of the infrared reflective layer is 0.1-0.3 mm.

[0121] In different embodiments, the thickness of the carrier layer can be 0.05mm, 0.08mm, 0.1mm, 0.15mm, 0.2mm or any combination thereof; the thickness of the light transfer layer can be 0.1mm, 0.15mm, 0.2mm, 0.25mm, 0.3mm or any combination thereof; and the thickness of the infrared reflective layer can be 0.1mm, 0.15mm, 0.2mm, 0.25mm, 0.3mm or any combination thereof.

[0122] The present invention also provides a method for preparing any of the above-mentioned high-reflectivity encapsulating films for gridless battery modules, comprising the following steps:

[0123] The carrier layer, light transfer layer and infrared reflective layer are co-extruded, stretched and pulled according to the raw material ratio, and then one side of the carrier layer is subjected to electron beam irradiation pre-crosslinking treatment to obtain a high reflective encapsulation film.

[0124] In practice, the extrusion temperature of the carrier layer, light transfer layer, and infrared reflective layer can be 90–95℃.

[0125] In a specific embodiment of the present invention, the degree of pre-crosslinking in the electron beam irradiation pre-crosslinking treatment is 1% to 60%.

[0126] In different embodiments, the degree of pre-crosslinking can be 1%, 5%, 10%, 15%, 20%, 30%, 40%, 50%, 60%, or any combination thereof. In the electron beam irradiation pre-crosslinking treatment, the electron beam irradiation parameters are a voltage of 0.5 MV, a beam current of 30 mA, and a linear velocity of 30 M / min.

[0127] In another aspect, the present invention provides a photovoltaic module, including any of the above-mentioned high-reflectivity encapsulating films for gridless cell modules.

[0128] In a specific embodiment of the present invention, the photovoltaic module includes at least one of the following: busbarless HJT, TOPCon, and BC type modules.

[0129] In a specific embodiment of the present invention, the photovoltaic module further includes solar cells and glass; the carrier layer in the encapsulating film is attached to the solar cells, and the infrared reflective layer in the encapsulating film is attached to the glass.

[0130] The present invention has a carrier layer in contact with the battery cell and an infrared reflective layer in contact with the glass. Neither of them is EVA resin and has high water resistance. They are not prone to generating acetate ions that corrode the battery cell and will not react with the glass surface to form a large number of Na ions. At the same time, due to the three-layer film structure, the multi-layer phase interface can effectively alleviate the migration of Na ions and reduce the PID degradation of the module.

[0131] The high-reflectivity encapsulating film for gridless battery modules of the present invention is mainly used on the back side of gridless battery modules; for gridless HJT or TOPCon modules, conventional gridless integrated encapsulating film is used on the front side; for BC type gridless modules, conventional high-transparency or cut-off type EVA encapsulating film is used on the front side.

[0132] Example 1

[0133] This embodiment provides a high-reflectivity encapsulating film for a gridless battery module, comprising a carrier layer, a light transfer layer, and an infrared reflective layer stacked sequentially. The thickness of the carrier layer is 0.1 mm, the thickness of the light transfer layer is 0.2 mm, and the thickness of the infrared reflective layer is 0.2 mm.

[0134] The raw materials for the support layer include the following components by weight: 65 parts TPO resin (Qatar Petrochemical LDPE, model FD0474), 35 parts POE resin (Dow POE, model 38680), and Eu... 3+ The modified organic photoconversion powder consists of 0.3 parts, 1 part, silane coupling agent, 0.5 parts, crosslinking agent, 0.5 parts, co-crosslinking agent, 0.5 parts, acrylic monomer, 0.05 parts, light stabilizer, and 0.05 parts, respectively. The silane coupling agent is vinyltriethoxysilane, the crosslinking agent is tert-butylperoxycarbonate-2-ethylhexyl ester, the co-crosslinking agent is triallyl isocyanurate, the antioxidant is β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate octadecyl alcohol ester, and the light stabilizer is bis(2,2,6,6-tetramethyl-4-piperidinyl) sebacate.

[0135] The raw materials for the phototransfer layer include the following components by weight: 100 parts EVA resin, Eu... 3+ The modified organic photoconversion powder consists of 0.3 parts, 1 part, silane coupling agent, 0.5 parts, crosslinking agent, 0.5 parts, co-crosslinking agent, 0.5 parts, acrylic monomer, 0.05 parts, light stabilizer, and 0.05 parts, respectively. The silane coupling agent is vinyltriethoxysilane, the crosslinking agent is tert-amyl peroxide (2-ethylhexyl) carbonate, the co-crosslinking agent is triallyl isocyanurate, the antioxidant is octadecyl β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, and the light stabilizer is bis(2,2,6,6-tetramethyl-4-piperidinyl) sebacate.

[0136] The raw materials for the infrared reflective layer include the following components by weight: 100 parts POE resin, Eu... 3+The mixture contains 0.3 parts of modified organic photoconversion powder, 5 parts of rare earth manganese oxide YMnO3, 1 part of silane coupling agent, 0.5 parts of crosslinking agent, 0.5 parts of co-crosslinking agent, 0.5 parts of acrylic monomer, 0.05 parts of light stabilizer, and 0.05 parts of antioxidant. The silane coupling agent is vinyltriethoxysilane, the crosslinking agent is tert-butylperoxycarbonate-2-ethylhexyl ester, the co-crosslinking agent is triallyl isocyanurate, the antioxidant is β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate octadecyl alcohol ester, and the light stabilizer is bis(2,2,6,6-tetramethyl-4-piperidinyl) sebacate.

[0137] Eu 3+ The preparation methods of modified organic photoconversion powders include:

[0138] (a) Weigh 2g of acrylamide, 0.1g of CdSO4·8 / 3H2O, and 0.08g of ammonium persulfate and dissolve them in 8g of deionized water. Stir until dissolved to prepare an aqueous phase. Weigh 1.6g of Span 80 and dissolve it in 40g of cyclohexane. Stir magnetically for 10min to prepare an oil phase. Slowly pour the aqueous phase into the oil phase and pre-emulsify magnetically for 15min. Sonicate the pre-emulsion for 5min, pour it into a four-necked flask, turn on the stirrer, and react in a water bath at 65℃ for 4h under N2 protection to obtain a CdSO4-PAM emulsion. The AM conversion rate was determined to be approximately 99% by gas chromatography.

[0139] (b) Weigh 0.094 g Na2S·9H2O and 0.3 g acrylamide and dissolve them in 2 g deionized water and stir until dissolved to obtain an aqueous solution of Na2S;

[0140] (c) Na₂S aqueous solution was added dropwise to CdSO₄-PAM emulsion at a constant rate of 10 mL / h using a micro-injection pump, and then the reaction was carried out at 65°C with stirring and in a sealed environment for 3 h. 30 g of EuCl₃·6H₂O was dissolved in 300 g of deionized water to obtain an EuCl₃·6H₂O aqueous solution. This EuCl₃·6H₂O aqueous solution was then added dropwise to CdSO₄-PAM emulsion at a constant rate of 100 mL / h using a micro-injection pump, and the reaction was carried out at 65°C with stirring and in a sealed environment for 2 h to obtain the final product. 3+ Doped CdS-PAM composite emulsion;

[0141] (d) Measure the Eu obtained in step (c). 3+ The doped CdS-PAM composite emulsion was poured into a polytetrafluoroethylene-lined hydrothermal reactor and placed in a constant-temperature forced-air drying oven. The reaction was carried out at 100°C for 6 hours. After centrifugation, the resulting precipitate was washed twice with anhydrous ethanol and then dried in a 50°C vacuum drying oven for 10 hours to obtain Eu. 3+ CdS quantum dot powder;

[0142] (e) Weigh 100 parts by weight of benzotriazole photoconverter as shown in Formula I, 5 parts by weight of UV-329, and 5 parts by weight of Eu 3+ CdS quantum dot powder was added to 10 mL of ethyl acetate and mixed thoroughly. Then, 5 parts by weight of tetraethyl orthosilicate, 3 parts by weight of 3-methacryloyloxypropyltrimethoxysilane, and 0.5 parts by weight of a water / ethanol mixture (ethanol to water volume ratio of 1:1) were added. The mixture was sonicated at room temperature for 30 min, and the solvent was removed by rotary evaporation at 65 °C and dried to obtain Eu. 3+ Modified organic phototransfer powder.

[0143] The method for preparing the high-reflectivity encapsulating film for gridless battery modules in this embodiment includes the following steps: The raw materials for the carrier layer, light transfer layer, and infrared reflective layer are respectively fed into three barrels; the three materials are melt-extruded through three independent dies (A, B, and C); the carrier layer, mixed in proportion, is fed into die A; the temperatures of each zone of the single-screw extruder are set as follows: Zone I 60–70℃, Zone II 70–80℃, Zone III 75–90℃, Zone IV 75–90℃, Zone V 75–90℃, Zone VI 80–100℃, Zone VII 80–100℃, Zone VIII 85–110℃, Zone IX 85–110℃, and the die head zone 120℃; the light transfer layer and infrared reflective layer, mixed in proportion, are fed into die B. The temperatures of each zone of the single-screw extruder, as described in section C, are set as follows: Zone I 60–70℃, Zone II 70–80℃, Zone III 75–90℃, Zone IV 75–90℃, Zone V 75–90℃, Zone VI 80–90℃, Zone VII 80–90℃, Zone VIII 80–90℃, Zone IX 80–90℃, and the die head zone 90℃. The three dies (A, B, and C) are used for melt extrusion, stretching, traction, and winding, resulting in a total encapsulation film thickness of 0.5 mm. Then, the carrier layer side of the encapsulation film is subjected to electron beam irradiation pre-crosslinking treatment with a voltage of 0.5 MV, a beam current of 30 mA, and a linear velocity of 30 M / min, achieving a pre-crosslinking degree of 30%, thus obtaining a high-reflectivity encapsulation film.

[0144] Example 2

[0145] This embodiment refers to the high-reflectivity encapsulating film and preparation method for the gridless battery module in Embodiment 1, with the only difference being: Eu 3+ In the preparation of modified organic photoconversion powder, the benzotriazole photoconversion powder used in step (e) is different.

[0146] In this embodiment, an equal weight of benzotriazole photoconverter powder of formula II is used to replace the benzotriazole photoconverter powder of formula I in Example 1.

[0147] Example 3

[0148] This embodiment refers to the high-reflectivity encapsulating film and preparation method for the gridless battery module in Embodiment 1, the only difference being: the Eu in the infrared reflective layer. 3+ The amount of modified organic photoconversion powder and rare earth manganese oxide used is different.

[0149] In this embodiment, Eu 3+ The amount of modified organic photoconversion powder is 0.5 parts and rare earth manganese oxide YMnO3 is 10 parts.

[0150] Example 4

[0151] This embodiment refers to the high-reflectivity encapsulating film and preparation method for the gridless battery module in Embodiment 1, the only difference being: the Eu in the infrared reflective layer. 3+ The amount of modified organic photoconversion powder and rare earth manganese oxide used is different.

[0152] In this embodiment, Eu 3+ The amount of modified organic photoconversion powder is 0.05 parts and rare earth manganese oxide YMnO3 is 0.5 parts.

[0153] Example 5

[0154] This embodiment refers to the high-reflectivity encapsulating film and preparation method for the gridless battery module in Embodiment 1, with the only difference being: Eu 3+ In the preparation of modified organic photoconversion powder, steps (b) and (c) are different.

[0155] Step (b) of this embodiment includes: weighing 0.094g Na2S·9H2O and 0.3g acrylamide and dissolving them in 2g deionized water and stirring until dissolved to obtain an aqueous Na2S solution; weighing 0.4g Span 80 and dissolving it in 10g cyclohexane and stirring magnetically for 10min to prepare an oil phase; slowly pouring the aqueous Na2S solution into the oil phase, stirring magnetically to pre-emulsify for 15min, and then sonicating for 5min to obtain a fine Na2S emulsion.

[0156] Step (c) of this embodiment includes: adding the Na2S fine emulsion obtained in step (b) dropwise to the CdSO4-PAM emulsion at a constant rate of 10 mL / h using a micro-injection pump, and then reacting at 65°C with stirring in a sealed environment for 3 hours; dissolving 5 g of EuCl3·6H2O in 300 g of deionized water to obtain an EuCl3·6H2O aqueous solution; then adding the EuCl3·6H2O aqueous solution dropwise to the CdSO4-PAM emulsion at a constant rate of 100 mL / h using a micro-injection pump, and reacting at 65°C with stirring in a sealed environment for 2 hours to obtain the EuCl3·6H2O emulsion. 3+ Doped CdS-PAM composite emulsion.

[0157] Example 6

[0158] This embodiment refers to the high-reflectivity encapsulating film and preparation method for the gridless battery module in Embodiment 1, with the only difference being: Eu 3+ The preparation methods for CdS-doped quantum dot powders are different.

[0159] Eu in this embodiment 3+ The preparation of CdS quantum dot powder includes: the preparation of CdS quantum dot powder and Eu... 3+ Doping involves two steps.

[0160] Preparation of CdS quantum dots: CdS quantum dots were synthesized in aqueous solution using cadmium nitrate and thioacetamide as raw materials and N-acetyl-L-cysteine ​​(NAC) as a stabilizer. In a conical flask, 5 mL of 0.1 mol / L Cd(NO3)2 aqueous solution, 2.5 mL of 0.1 mol / L NAC aqueous solution, and 35 mL of deionized water were added sequentially and stirred until homogeneous. The pH was adjusted to 7 with ammonia and stirred for 10 min. 8 mL of thioacetamide was slowly added dropwise. After the addition was complete, the mixture was reacted at 80 °C for 2 h, allowed to stand, and cooled to room temperature to obtain a colorless and transparent solution. The solution was precipitated with anhydrous ethanol, centrifuged, and the precipitate was vacuum dried to obtain 0.059 g of pale yellow CdS quantum dot powder.

[0161] Eu 3+ Preparation of CdS quantum dots: The prepared CdS quantum dot powder was dissolved in 100 mL of deionized water. 30 g of EuCl3·6H2O was weighed and dissolved in 300 g of deionized water to obtain an EuCl3·6H2O aqueous solution. The EuCl3·6H2O aqueous solution was then added dropwise at a constant rate of 100 mL / h using a micro-injection pump. The reaction was carried out at 65 °C with stirring and kept in a sealed environment for 2 h. The mixture was then dried in a vacuum drying oven at 50 °C for 10 h to obtain the doped CdS quantum dots. 3+ CdS-doped quantum dot powder.

[0162] Comparative Example 1

[0163] Comparative Example 1 refers to the high-reflectivity encapsulating film and preparation method for a gridless solar cell module in Example 1, the difference being that: in Comparative Example 1, an equal weight of the first modified organic light-converting powder is used to replace the Eu in Example 1 in all three layers. 3+ Modified organic phototransfer powder.

[0164] The preparation of the first modified organic photoconversion powder in Comparative Example 1 included: weighing 100 parts by weight of benzotriazole photoconversion powder as shown in Formula I, 5 parts by weight of UV-329, and 5 parts by weight of CdS quantum dot powder, adding them to 10 mL of ethyl acetate, and mixing them evenly; then adding 5 parts by weight of tetraethyl orthosilicate, 3 parts by weight of 3-methacryloyloxypropyltrimethoxysilane, and 0.5 parts by weight of a water / ethanol mixture (the volume ratio of ethanol to water was 1:1), sonicating at room temperature for 30 min, removing the solvent by rotary evaporation at 65 °C, and drying to obtain the first modified organic photoconversion powder.

[0165] Comparative Example 2

[0166] Comparative Example 2 describes a high-reflectivity encapsulating film and its preparation method for a gridless solar cell module, with the difference being that in Comparative Example 2, an equal weight of a second modified organic light-converting powder replaces the Eu in Example 1 in all three layers. 3+ Modified organic phototransfer powder.

[0167] The preparation of the second modified organic photoconverter powder in Comparative Example 2 included: weighing 100 parts by weight of benzotriazole photoconverter powder as shown in Formula I, 5 parts by weight of UV-329, and 15 parts by weight of Eu. 3+ CdS quantum dot powder was added to 10 mL of ethyl acetate and mixed thoroughly. Then, 5 parts by weight of tetraethyl orthosilicate, 3 parts by weight of 3-methacryloyloxypropyltrimethoxysilane, and 0.5 parts by weight of a water / ethanol mixture (ethanol to water volume ratio of 1:1) were added. The mixture was sonicated at room temperature for 30 min, and the solvent was removed by rotary evaporation at 65 °C and dried to obtain the second modified organic photoconversion powder.

[0168] Comparative Example 3

[0169] Comparative Example 3 refers to the high-reflectivity encapsulating film and preparation method for the gridless battery module of Example 1, the difference being that the raw material composition of the infrared reflective layer is different.

[0170] The infrared reflective layer of Comparative Example 3 does not include rare earth manganese oxide YMnO3.

[0171] Comparative Example 4

[0172] Comparative Example 4 refers to the high-reflectivity encapsulating film and preparation method for the gridless battery module of Example 1, the difference being that the raw material composition of the infrared reflective layer is different.

[0173] In the infrared reflective layer of Comparative Example 4, the amount of rare earth manganese oxide YMnO3 was 15 parts.

[0174] Experimental Example 1

[0175] To compare and illustrate the performance differences of the encapsulating films in different embodiments and comparative examples, the infrared reflectance and water vapor transmittance of the encapsulating films in different embodiments and comparative examples were tested. The encapsulating films in different embodiments and comparative examples were made into photovoltaic module samples to be tested, and the tests were carried out according to the following test methods. The test results are shown in Table 1.

[0176] Reflectance test: The reflectance of 700-1100 nm was tested using a Lambda950 UV-Vis spectrophotometer.

[0177] Water vapor transmission rate test: The water vapor transmission rate was tested according to standard GB / T21529-2008 using a C390H water vapor transmission rate tester. The infrared sensor method was used to determine the water vapor transmission rate. The test conditions were 38℃ and 90% relative humidity.

[0178] Electroluminescence (EL) test of module lamination: Take the encapsulating film samples from the examples and comparative examples, and laminate them in the following order from top to bottom: glass, high-reflection encapsulating film for grid-less cell modules, OBBHJT cell, high-reflection encapsulating film for grid-less cell modules, and glass. Then, laminate them at 140°C for 10 minutes. Test the EL of the laminated modules according to the IEC 61215 & 61730 test standards.

[0179] The photovoltaic modules were tested using conventional methods according to standards IEC61215 and IEC61730 for temperature rise, power output increase, and PID testing. The photovoltaic modules used in the tests were Jinshi 166HJT solar cells, and the glass was ultra-clear patterned tempered glass.

[0180] Table 1 Test results of different encapsulating films

[0181]

[0182]

[0183] The test results above show that the high-reflectivity encapsulating film of the present invention is suitable for the back side of the busbarless module, which can fix the welding wire and avoid problems such as poor connection; at the same time, it has a high ability to block water vapor and shield ultraviolet rays, improve the aging resistance of the module, has low PID attenuation, can extend service life, can increase the power generation of the module by about 2%, and can also play a role in heat insulation to reduce the power generation temperature of the module.

[0184] 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 high-reflectivity encapsulating film for a gridless solar cell assembly, characterized in that, It includes a carrier layer, a light transfer layer, and an infrared reflective layer stacked in sequence; The supporting layer is mainly composed of the following components in parts by weight: 50-80 parts TPO resin, 20-50 parts POE resin, and Eu... 3+ 0.05–0.5 parts of modified organic photoconversion powder and 0.42–4.7 parts of the first additive; The phototransfer layer is mainly composed of the following components in parts by weight: 100 parts EVA resin, Eu 3+ 0.05–0.5 parts of modified organic photoconversion powder and 0.42–4.7 parts of second additive; The infrared reflective layer is mainly composed of the following components in parts by weight: 100 parts POE resin, Eu 3+ 0.05–0.5 parts of modified organic photoconversion powder, 0.5–10 parts of rare earth manganese oxide, and 0.42–4.7 parts of third auxiliary agent; Wherein, Eu 3+ The modified organic photoconversion powder is mainly prepared from the following components by weight: 100 parts of benzotriazole photoconversion powder, 1-10 parts of benzotriazole UV absorber, and Eu. 3+ The mixture consists of 1-10 parts of doped CdS quantum dot powder, 0.1-5 parts of silane coupling agent, 0.1-10 parts of silicate ester, 0.1-1 parts of hydrolysate, and 5-20 parts of solvent.

2. The high-reflectivity encapsulating film according to claim 1, characterized in that, The benzotriazole photoconverter includes at least one of the compounds represented by formulas I to II: 、 ； And / or, the rare earth manganese oxide is YMnO3.

3. The high-reflectivity encapsulating film according to claim 1, characterized in that, The Eu 3+ The preparation of CdS quantum dot powder includes: (a) Aqueous phase is obtained by mixing and dissolving water-soluble Cd salt, acrylamide and initiator in water; oil phase is obtained by dissolving nonionic surfactant in organic solvent; the aqueous phase is added to the oil phase, stirred and pre-emulsified, and then reacted at 60-80°C for 2-6 hours under a protective atmosphere to obtain Cd salt-PAM emulsion. (b) A solution containing sodium sulfide and acrylamide is added to the Cd salt-PAM emulsion and reacted at 60–80°C for 2–4 h. Then, an aqueous solution containing water-soluble Eu salt is added and reacted at 60–80°C for 1–3 h to obtain Eu. 3+ Doped CdS-PAM composite emulsion; (c) The Eu 3+ After hydrothermal reaction, the doped CdS-PAM nanoemulsion was collected and dried to obtain the Eu. 3+ CdS-doped quantum dot powder.

4. The high-reflectivity encapsulating film according to claim 3, characterized in that, The water-soluble Cd salt includes CdSO4. 8 / 3H2O.

5. The high-reflectivity encapsulating film according to claim 4, characterized in that, In step (a), the mass ratio of the water-soluble Cd salt to the acrylamide is 1:(15-25).

6. The high-reflectivity encapsulating film according to claim 4, characterized in that, The initiator is ammonium persulfate; the mass of the initiator is 1 wt% to 10 wt% of the mass of the acrylamide.

7. The high-reflectivity encapsulating film according to claim 3, characterized in that, The nonionic surfactant includes Span 80.

8. The high-reflectivity encapsulating film according to claim 7, characterized in that, The organic solvent includes cyclohexane.

9. The high-reflectivity encapsulating film according to claim 7, characterized in that, The mass ratio of the nonionic surfactant to the organic solvent is 1:(20-30).

10. The high-reflectivity encapsulating film according to claim 3, characterized in that, In the solution containing sodium sulfide and acrylamide, the mass ratio of sodium sulfide to acrylamide is 1:(2-4).

11. The high-reflectivity encapsulating film according to claim 10, characterized in that, The solution containing sodium sulfide and acrylamide is an aqueous solution or an emulsion.

12. The high-reflectivity encapsulating film according to claim 10, characterized in that, When the solution containing sodium sulfide and acrylamide is an emulsion, the emulsion also includes a nonionic surfactant and an organic solvent.

13. The high-reflectivity encapsulating film according to claim 3, characterized in that, In step (b), the mass ratio of the solution containing sodium sulfide and acrylamide to the Cd salt-PAM emulsion is 1:(2-20).

14. The high-reflectivity encapsulating film according to claim 13, characterized in that, In step (b), the amount of water-soluble Eu salt in the aqueous solution containing the water-soluble Eu salt is 0.5 to 15 times the mass of the acrylamide in step (a).

15. The high-reflectivity encapsulating film according to claim 14, characterized in that, The Eu 3+ The preparation of modified organic phototransfer powder includes: mixing the benzotriazole phototransfer powder, the benzotriazole UV absorber, and the Eu... 3+ CdS quantum doped powder was dispersed in a solvent, and a silane coupling agent, silicate ester, and hydrolysate were added. After hydrolysis, the solvent was removed and the mixture was dried to obtain the Eu. 3+ Modified organic phototransfer powder.

16. The high-reflectivity encapsulating film according to claim 1, characterized in that, The thickness ratio of the carrier layer, the light transfer layer and the infrared reflective layer is 1:(1.5~2.5):(1.5~2.5).

17. The high-reflectivity encapsulating film according to claim 16, characterized in that, The thickness of the bearing layer is 0.05 to 0.2 mm.

18. The high-reflectivity encapsulating film according to claim 16, characterized in that, The thickness of the optical transfer layer is 0.1–0.3 mm.

19. The high-reflectivity encapsulating film according to claim 16, characterized in that, The thickness of the infrared reflective layer is 0.1 to 0.3 mm.

20. The method for preparing the high-reflectivity encapsulating film according to any one of claims 1 to 19, characterized in that, Includes the following steps: The carrier layer, light transfer layer and infrared reflective layer are co-extruded, stretched and pulled according to the raw material ratio, and then one side of the carrier layer is subjected to electron beam irradiation pre-crosslinking treatment.

21. The preparation method according to claim 20, characterized in that, In the electron beam irradiation pre-crosslinking treatment, the degree of pre-crosslinking is 1% to 60%.

22. A photovoltaic module, characterized in that, The high-reflectivity encapsulating film includes the high-reflectivity encapsulating film according to any one of claims 1 to 19 or the high-reflectivity encapsulating film prepared by the preparation method according to any one of claims 20 to 21.

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