阅读说明：本技术 一种光伏组件用透明背板及其制备方法 (Transparent back plate for photovoltaic module and preparation method thereof ) 是由 詹志英 杨楚峰 林建华 于 2019-10-30 设计创作，主要内容包括：本发明公开了一种光伏组件用透明背板及其制备方法。本发明的透明背板由外至内依次包括疏水改性的聚偏氟乙烯膜层、第一碳氟涂料层、透明基板、第二碳氟涂料层；制备方法包括如下步骤：在透明基板两侧分别涂覆第一碳氟涂料层和第二碳氟涂料层,得到双面涂覆型透明基材；在双面涂覆型透明基材的第一碳氟涂料层外层涂布疏水改性的聚偏氟乙烯铸膜液,疏水改性的聚偏氟乙烯铸膜液经相转化法在双面涂覆型透明基板外层形成疏水改性的聚偏氟乙烯膜层。本发明具有制备工艺简单、经济环保、耐候性佳且可以自清洁等优点。(The invention discloses a transparent back plate for a photovoltaic module and a preparation method thereof. The transparent back plate comprises a hydrophobic modified polyvinylidene fluoride film layer, a first fluorocarbon coating layer, a transparent substrate and a second fluorocarbon coating layer from outside to inside in sequence; the preparation method comprises the following steps: respectively coating a first fluorocarbon coating layer and a second fluorocarbon coating layer on two sides of a transparent substrate to obtain a double-coated transparent substrate; coating a hydrophobic modified polyvinylidene fluoride casting solution on the outer layer of the first fluorocarbon coating layer of the double-coated transparent substrate, and forming a hydrophobic modified polyvinylidene fluoride film layer on the outer layer of the double-coated transparent substrate by a phase inversion method through the hydrophobic modified polyvinylidene fluoride casting solution. The invention has the advantages of simple preparation process, economy, environmental protection, good weather resistance, self-cleaning and the like.)

1. The transparent back plate for the photovoltaic module is characterized by comprising a hydrophobic modified polyvinylidene fluoride film layer, a first fluorocarbon coating layer, a transparent substrate and a second fluorocarbon coating layer from outside to inside in sequence; the hydrophobic modified polyvinylidene fluoride film layer is prepared by a phase transfer method.

2. The transparent backsheet for photovoltaic modules according to claim 1, wherein said transparent substrate is a PET film.

3. The transparent backsheet for photovoltaic modules as claimed in claim 1, wherein the thickness of the hydrophobically modified polyvinylidene fluoride film layer is 5-25 μm, the thickness of the first fluorocarbon coating layer is 1-5 μm, the thickness of the transparent substrate is 200-300 μm, and the thickness of the second fluorocarbon coating layer is 2-20 μm.

4. The transparent backsheet for photovoltaic modules according to claim 1, wherein said hydrophobically modified polyvinylidene fluoride film layer is modified by adding fumed silica to polyvinylidene fluoride.

5. The transparent backsheet for photovoltaic modules according to claim 4, wherein said fumed silica is added in an amount of 0.05 to 1% by mass of the polyvinylidene fluoride.

6. A process for the preparation of a transparent backsheet for photovoltaic modules according to any one of claims 1 to 5, comprising the steps of:

(1) respectively coating a first fluorocarbon coating layer and a second fluorocarbon coating layer on two sides of a transparent substrate to obtain a double-coated transparent substrate;

(2) coating a hydrophobic modified polyvinylidene fluoride casting solution on the outer layer of the first fluorocarbon coating layer of the double-coated transparent substrate, and forming a hydrophobic modified polyvinylidene fluoride film layer on the outer layer of the double-coated transparent substrate by a phase inversion method through the hydrophobic modified polyvinylidene fluoride casting solution.

7. The preparation method according to claim 6, wherein the phase inversion method comprises the following specific steps: coating the casting solution on the outer layer of the first fluorocarbon coating layer of the double-sided coating type transparent substrate, then pre-evaporating the substrate coated with the casting solution in the air, rapidly introducing a solidification solution into the substrate coated with the casting solution within 20s for precipitation and solidification for 0.1-10min, and finally airing to form a film.

8. The method according to claim 6, wherein the casting solution is prepared by: adding 5-30 parts of polyvinylidene fluoride powder into 100 parts of organic solvent, stirring at low temperature to completely dissolve the polyvinylidene fluoride powder into clear solution, adding fumed silica accounting for 0.05-1% of the mass of the polyvinylidene fluoride, and uniformly stirring to obtain the polyvinylidene fluoride-containing aqueous solution.

9. The preparation method according to claim 6, wherein the coagulating liquid is a mixture of water and an organic solvent, and the organic solvent is one or a combination of ethanol, propanol, acetone, N-methylpyrrolidone, N-dimethylformamide, dimethylacetamide, dimethylsulfoxide and tetrahydrofuran.

10. The method for preparing the polyvinylidene fluoride membrane of claim 6, wherein a high temperature heat treatment step is added after the step (2) in order to strengthen the hydrophobically modified polyvinylidene fluoride membrane layer.

Technical Field

The invention belongs to the technical field of photovoltaic cell packaging, and particularly relates to a transparent back plate for a photovoltaic module and a preparation method thereof.

Background

At present, the photovoltaic power generation in China is continuously and rapidly developed, the technical level is continuously improved, the industrial system is continuously improved, particularly, with the development of high-efficiency technology, the power generation power of a photovoltaic module is higher and higher, the era of online low price of industry comes quickly, and the development of new energy industry in China is favorably promoted.

The development of high efficiency technologies such as double-sided components, half-chip technology, large-block components, reduced gap spacing, and the like, fully illustrate the broad prospects of transparent backplanes. As a packaging protective material for the outermost layer of a photovoltaic module, the transparent back sheet needs to satisfy conventional properties such as electrical insulation, water vapor barrier property and the like of a conventional back sheet, and also needs to have high transmittance, good adhesion and good weather resistance, particularly excellent ultraviolet resistance. Generally, there are two kinds of transparent back plates, namely a glass back plate and a polymer-based transparent back plate, the former has high cost, heavy components and a risk of bursting, the latter has a poor weather resistance, pure PET has poor weather resistance and is eliminated, and composite other film layers have problems of large yellowing, high fluorine film cost and the like, but the optimization design of the latter is a better technical development trend.

Chinese patent CN 104842616B discloses a photovoltaic solar cell composite back panel, which is a PET and polyester co-extrusion film, wherein inorganic nano particles are added, and a fluorine-containing polymer is coated on the outer layer of the back panel to serve as an ultraviolet-proof layer, in order to solve the problems of weather resistance, water vapor barrier property, insulativity and weak strength of the back panel of the solar cell back panel. But the weather resistance and self-cleaning ability still need to be improved.

Chinese patent CN 103560162B discloses a solar cell back panel, the outside surface of the PET substrate of the back panel is provided with a polyvinylidene fluoride film layer, and the inside surface of the PET substrate is coated with a fluorocarbon resin coating. But the radiation curing preparation process increases the process cost and the process difficulty.

Disclosure of Invention

In order to solve the problems in the prior art, the invention aims to provide a transparent back sheet for a photovoltaic module and a preparation method thereof. The invention has the advantages of simple preparation process, economy, environmental protection, good weather resistance, self-cleaning and the like.

In order to achieve the purpose, the invention adopts the following technical scheme:

a transparent back plate for a photovoltaic module comprises a hydrophobic modified polyvinylidene fluoride film layer, a first fluorocarbon coating layer, a transparent substrate and a second fluorocarbon coating layer from outside to inside in sequence; the hydrophobic modified polyvinylidene fluoride film layer is prepared by a phase transfer method.

Further, the transparent substrate is a PET film.

Further, the thickness of the hydrophobic modified polyvinylidene fluoride film layer is 5-25 μm, the thickness of the first fluorocarbon coating layer is 1-5 μm, the thickness of the transparent substrate is 200-300 μm, and the thickness of the second fluorocarbon coating layer is 2-20 μm.

Preferably, the thickness of the second fluorocarbon coating layer is 5 to 13 μm.

Preferably, the thickness of the transparent substrate is 240-280 μm.

Further, the hydrophobic modified polyvinylidene fluoride film layer is obtained by adding fumed silica into polyvinylidene fluoride for modification.

Preferably, the addition amount of the fumed silica is 0.05-1% of the mass of the polyvinylidene fluoride.

Preferably, the polyvinylidene fluoride has a viscosity average molecular weight of 70 ten thousand or more.

Further, the first fluorocarbon coating layer and the second fluorocarbon coating layer are mainly composed of fluorocarbon resin, modified resin and inorganic filler.

Preferably, the modified resin is one or more of butanol etherified amino resin, bisphenol A epoxy resin, C5 petroleum resin, bisphenol F epoxy resin, polyphenol glycidyl ether epoxy resin, organic silicon resin and aliphatic glycidyl ether epoxy resin which are mixed according to any proportion.

Preferably, the inorganic filler is one or more of nano titanium dioxide, montmorillonite, transparent powder, scratch-resistant powder, glass fiber powder, ceramic microspheres, silica micropowder, white carbon black, glass powder, nano zinc oxide and matting powder which are mixed according to any proportion; the particle size of the inorganic filler is 50nm-10 um.

The invention also provides a preparation method of the transparent back plate for the photovoltaic module, which comprises the following steps:

(1) respectively coating a first fluorocarbon coating layer and a second fluorocarbon coating layer on two sides of a transparent substrate to obtain a double-coated transparent substrate;

(2) coating a hydrophobic modified polyvinylidene fluoride casting solution on the outer layer of the first fluorocarbon coating layer of the double-coated transparent substrate, and forming a hydrophobic modified polyvinylidene fluoride film layer on the outer layer of the double-coated transparent substrate by a phase inversion method through the hydrophobic modified polyvinylidene fluoride casting solution.

Further, the phase inversion method comprises the following specific steps: coating the casting solution on the first fluorocarbon coating layer of the double-sided coating type transparent substrate, then pre-evaporating the substrate coated with the casting solution in air, rapidly introducing the solidification solution into the substrate coated with the casting solution for precipitation and solidification for a period of time, and finally airing to form a film, wherein the rapid introduction is the time of the substrate coated with the casting solution staying in the air, and within 20 seconds, the preferred precipitation and solidification time is 0.1-10 minutes.

Further, the preparation method of the casting solution comprises the following steps: adding 5-30 parts of polyvinylidene fluoride powder into 100 parts of organic solvent, stirring at low temperature to completely dissolve the polyvinylidene fluoride powder into clear solution, adding fumed silica accounting for 0.05-1% of the mass of the polyvinylidene fluoride, and uniformly stirring to obtain the polyvinylidene fluoride-containing aqueous solution.

Preferably, the organic solvent is one or a combination of acetone, N-methyl pyrrolidone, N-dimethylformamide, dimethylacetamide, dimethyl sulfoxide and tetrahydrofuran.

Preferably, the low-temperature stirring temperature is 20-80 ℃.

Further, the coating method is blade coating, and the thickness of the coating is adjusted by adjusting the positions of the blade and the double-coated transparent substrate. The thickness of the coating is basically equivalent to that of the final hydrophobic modified polyvinylidene fluoride membrane layer.

Further, the coagulating liquid is water or a mixture of water and an organic solvent, and the organic solvent is one or a combination of ethanol, propanol, acetone, N-methylpyrrolidone, N-dimethylformamide, dimethylacetamide, dimethyl sulfoxide and tetrahydrofuran.

Further, the drying is natural drying or blast drying through a drying tunnel.

Further, in order to strengthen the hydrophobic modified polyvinylidene fluoride membrane layer, a high-temperature heat treatment step is added after the step (2).

Preferably, the temperature of the high-temperature heat treatment is 100-150 ℃, and the time is 0.5-5 min.

Further, the specific steps of the step (1) are as follows: the fluorocarbon resin, the modified resin, the curing agent, the inorganic filler, the auxiliary agent and the solvent are mixed according to a certain proportion to prepare a transparent fluorocarbon coating, one surface of a transparent substrate is coated and cured at high temperature to obtain a first fluorocarbon coating layer, and then the other surface of the transparent substrate is coated with the coating and cured at high temperature to obtain a second fluorocarbon coating layer.

Preferably, the high-temperature curing temperature is 150-.

The invention has the following technical characteristics:

1. the outermost layer of the transparent back plate is the hydrophobic modified polyvinylidene fluoride film layer prepared by the phase inversion method, the prepared polyvinylidene fluoride film is a thermoplastic film layer, the process is simple and easy to operate, and the used solidification liquid can be recycled and reused, so that the transparent back plate is economic and environment-friendly.

2. The polyvinylidene fluoride membrane prepared by the method belongs to a hydrophobic material, and the hydrophobicity is enhanced by the fumed silica, so that the air side surface of the transparent back plate has larger hydrophobicity, the transparent back plate has a self-cleaning effect due to the high hydrophobicity, the pollution degree of a photovoltaic module in the outdoor use process is effectively reduced, and the better power generation efficiency of the photovoltaic module is ensured.

3. The transparent back plate has outdoor weather resistance of the conventional back plate, the outer layer of the transparent back plate consists of a thin fluorocarbon coating and a thick polyvinylidene fluoride film in sequence from inside to outside, and the two layers are designed in a gradient manner, so that the cost of the transparent back plate is controlled to a certain extent. Furthermore, the method of the present invention is equally applicable to white or black backplanes.

Drawings

Fig. 1 is a schematic structural diagram of a transparent back plate for a photovoltaic module according to the present invention, which is composed of a hydrophobic modified polyvinylidene fluoride film layer 1, a first fluorocarbon coating layer 2, a transparent substrate 3, and a second fluorocarbon coating layer 4 sequentially from top to bottom.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below. It is to be understood that the embodiments described are only a few embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the described embodiments of the invention without any inventive step, are within the scope of protection of the invention.

Unless defined otherwise, technical or scientific terms used herein shall have the ordinary meaning as understood by one of ordinary skill in the art to which this invention belongs.

Fig. 1 is a schematic structural diagram of a transparent back plate for a photovoltaic module, which is composed of a hydrophobic modified polyvinylidene fluoride film layer 1, a first fluorocarbon coating layer 2, a transparent substrate 3 and a second fluorocarbon coating layer 4 from top to bottom in sequence.

The transparent back plate for the photovoltaic module in the specific embodiment of the invention is prepared by the following steps:

(1) respectively coating a first fluorocarbon coating layer and a second fluorocarbon coating layer on two sides of a transparent substrate to obtain a double-coated transparent substrate;

(2) coating a hydrophobic modified polyvinylidene fluoride casting solution on the outer layer of the first fluorocarbon coating layer of the double-coated transparent substrate, and forming a hydrophobic modified polyvinylidene fluoride film layer on the outer layer of the double-coated transparent substrate by a phase inversion method through the hydrophobic modified polyvinylidene fluoride casting solution.

In certain preferred embodiments, the specific steps of step (1) are: the fluorocarbon resin, the modified resin, the curing agent, the inorganic filler, the auxiliary agent and the solvent are mixed according to a certain proportion to prepare a transparent fluorocarbon coating, one surface of a transparent substrate is coated and cured at high temperature to obtain a first fluorocarbon coating layer, and then the other surface of the transparent substrate is coated with the coating and cured at high temperature to obtain a second fluorocarbon coating layer.

In certain preferred embodiments, the fluorocarbon resin is selected from the group consisting of tetrafluoroethylene/vinyl ether copolymers, tetrafluoroethylene/vinyl ester copolymers, tetrafluoroethylene/alkyl vinyl ether copolymers, tetrafluoroethylene/alkyl vinyl ester copolymers; the modified resin is selected from bisphenol A type epoxy resin, bisphenol F type epoxy resin, alkyl glycidyl ether epoxy resin and butanol etherified amino resin; the curing agent is selected from hexamethylene diisocyanate tripolymer, hexamethylene diisocyanate biuret, diphenylmethane diisocyanate tripolymer, isophorone diisocyanate tripolymer and isophorone diisocyanate prepolymer; the inorganic filler is selected from nano titanium dioxide, transparent powder, scratch-resistant powder, ceramic microspheres, white carbon black, glass powder and matting powder; the auxiliary agent is selected from block copolymer dispersant containing pigment affinity group, polyether modified polysiloxane flatting agent, aralkyl modified polysiloxane flatting agent, polyester modified polysiloxane flatting agent, reaction type polysiloxane flatting agent, 2-hydroxy-4-n-octyloxy benzophenone, 2- (2' -hydroxy-3 ',5' -di-tert-phenyl) -5-chlorinated benzotriazole, bis (1, 2,2,6, 6-pentamethyl-4-piperidyl) -sebacate/mono (1, 2,2,6, 6-pentamethyl-4-piperidyl) sebacate compound, bis (2,2,6, 6-tetramethyl-4-piperidyl) sebacate, tetra (3, 5-di-tert-butyl-4-hydroxy) phenylpropionic acid pentaerythritol ester, N-octadecyl beta- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate; the solvent is selected from xylene, butyl acetate, propylene glycol methyl ether acetate, methyl isobutyl ketone and isopropanol;

in certain preferred embodiments, the high temperature curing temperature is 150 ℃ and 200 ℃ for 1.5-6 min.

Specific examples are as follows, and the parts in the following examples refer to parts by weight: