A solar cell back panel and its preparation method and application

Abstract

The present invention provides a solar cell back sheet and a preparation method and application thereof, wherein the solar cell back sheet has a single-layer structure or a multi-layer structure; when the solar cell back sheet has a single-layer structure, the raw materials for its preparation include polyethylene resin and modified polyethylene resin; when the solar cell back sheet has a multi-layer structure, it includes a protective layer, an intermediate core layer and an adhesive layer arranged in sequence; the raw materials for the preparation of the protective layer and the adhesive layer both include polyethylene resin and modified polyethylene resin. The solar cell back sheet provided by the present invention does not contain fluorine, the raw materials for its preparation do not involve PP and nylon, and has excellent weather resistance, excellent electrical insulation, water vapor barrier and aging resistance.

Description

Technical Field

[0001] The invention belongs to the technical field of photovoltaic cell assemblies and relates to a solar cell back panel and a preparation method and application thereof. Background Art

[0002] In the photovoltaic power generation industry, the backsheet plays a vital role in protecting and supporting the back of the solar cell module. Its main requirements include providing reliable electrical insulation, excellent water vapor barrier and durable aging resistance. At present, the backsheet of photovoltaic modules can generally be divided into two types: fluorine-containing and fluorine-free.

[0003] Although fluorinated backsheets have excellent weather resistance and protection properties, their use faces problems such as poor environmental friendliness and high production costs, resulting in a continuous decline in their market share. These factors have led to an increasingly urgent demand for more environmentally friendly and cost-effective alternatives.

[0004] Fluorine-free backsheets are usually made of different materials, including PET coating, PET composite polyolefin film and polypropylene composite material. However, traditional fluorine-free backsheets have a series of problems during use, such as the complex processing technology and poor reliability of PET, polypropylene PP and nylon as water barrier and adhesive, prone to cracking, delamination, insufficient heat resistance and wrinkles during hot pressing, and PP itself has poor low temperature resistance and is prone to cracking at low temperatures. These problems seriously affect the performance and life of the components.

[0005] Therefore, in the art, it is desired to develop a solar cell back sheet that does not contain fluorine, whose preparation raw materials do not involve PP and nylon, and has excellent weather resistance, outstanding electrical insulation, water vapor barrier and aging resistance. Summary of the invention

[0006] In view of the shortcomings of the prior art, the object of the present invention is to provide a solar cell back sheet and a preparation method and application thereof. The solar cell back sheet of the present invention is suitable for solar cell modules that require higher heat resistance, mechanical strength and cost-effectiveness.

[0007] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0008] In a first aspect, the present invention provides a solar cell back sheet, wherein the solar cell back sheet has a single-layer structure or a multi-layer structure;

[0009] When the solar cell back sheet has a single-layer structure, its preparation raw materials include polyethylene resin and modified polyethylene resin;

[0010] When the solar cell back sheet has a multi-layer structure, it includes a protective layer, an intermediate core layer and an adhesive layer arranged in sequence;

[0011] The raw materials for preparing the protective layer and the bonding layer both include polyethylene resin and modified polyethylene resin.

[0012] The solar cell back panel provided by the present invention uses polyethylene resin as the main material, avoids the use of PET, PP and nylon resin, has a low processing temperature (150-180°C), and has excellent weather resistance, outstanding electrical insulation, water vapor barrier and aging resistance.

[0013] When the solar cell back sheet provided by the present invention has a multi-layer structure, the material structures between the layers are similar, the compatibility is excellent, and there is no risk of delamination. As a preferred embodiment, the linear low-density polyethylene content in the adhesive layer on the film side is not less than 50%, so that it has excellent adhesion with the encapsulation film, avoiding the risk of delamination between the back sheet and the film.

[0014] In the present invention, the multi-layer structure refers to at least a three-layer structure, preferably a three-layer, four-layer or five-layer structure, and more preferably a three-layer structure.

[0015] When the solar cell back panel provided by the present invention has a three-layer structure, the protective layer is the layer that is in direct contact with the external atmospheric environment, and has excellent weather resistance, scratch resistance and high hardness; the middle core layer is the second layer, which is a water-blocking layer and also plays a certain supporting role, and has excellent mechanical strength and water-blocking effect; the bonding layer is the inner layer, which is in contact with the adhesive film and has excellent bonding properties with the adhesive film.

[0016] Preferably, the raw materials for preparing the protective layer include the following components in parts by weight:

[0017]

[0018] Preferably, the raw materials for preparing the protective layer are measured in parts by weight, and the amount of polyethylene resin used can be 50 parts, 55 parts, 60 parts, 65 parts, 70 parts, 75 parts, 80 parts, 85 parts, 90 parts, etc.

[0019] Preferably, the raw materials for preparing the protective layer are measured in parts by weight, and the amount of the modified polyethylene resin used can be 1 part, 3 parts, 5 parts, 8 parts, 10 parts, 13 parts, 15 parts, 18 parts, 20 parts, etc.

[0020] Preferably, the raw materials for preparing the protective layer can be used in an amount of acrylate monomers in parts by weight, such as 1 part, 3 parts, 5 parts, 8 parts, 10 parts, 13 parts, 15 parts, etc.

[0021] Preferably, the raw materials for preparing the protective layer are measured by weight, and the amount of filler used can be 35 parts, 40 parts, 45 parts, 50 parts, 55 parts, etc.

[0022] Preferably, the amount of the sensitizer used in preparing the protective layer can be 0.1 parts, 0.3 parts, 0.5 parts, 0.8 parts, 1 parts, 1.3 parts, 1.5 parts, 1.8 parts, 2 parts, etc., based on the weight parts of the raw materials.

[0023] Preferably, the raw materials for preparing the protective layer are measured in parts by weight, and the amount of the auxiliary agent used can be 0 parts, 0.1 parts, 0.3 parts, 0.5 parts, 0.8 parts, 1 parts, 1.3 parts, 1.5 parts, 1.8 parts, 2 parts, etc.

[0024] Preferably, the polyethylene resin in the protective layer includes any one of LDPE, LLDPE, HDPE or MDPE, or a combination of at least two thereof.

[0025] Preferably, the modified polyethylene resin in the protective layer includes any one or a combination of at least two of ethylene-acrylate copolymer, ethylene-methyl methacrylate copolymer, polyethylene-maleic anhydride graft, ethylene-vinyl acetate copolymer, ethylene-octene copolymer, ethylene-butene copolymer, silicone-modified acrylic resin, silicone-modified resin, vinyl resin, ethylene-acrylic acid copolymer, ethylene-butyl acrylate copolymer or POE-glycidyl acrylate graft.

[0026] Preferably, the acrylic acid ester monomer in the protective layer includes any one of methyl acrylate, methyl methacrylate, hydroxyethyl acrylate, hydroxyethyl methacrylate, lauryl methacrylate or tripropylene glycol diacrylate, or a combination of at least two thereof;

[0027] Preferably, the filler in the protective layer includes any one of titanium dioxide, modified titanium dioxide, carbon black, perylene black, copper black, aluminum oxide, aluminum hydroxide, magnesium hydroxide, aluminum oxide, magnesium oxide, talc, silicon dioxide, modified silicon dioxide, calcium carbonate, mica powder, barium sulfate, modified diatomaceous earth, pumice powder or modified diamond powder, or a combination of at least two thereof.

[0028] Preferably, the sensitizer in the protective layer includes any one of triallyl cyanurate (TAIC), tripropargyl cyanurate (TAC), trimethylolpropane trimethacrylate (TMPTMA), trimethylolpropane triacrylate (TMPTA), or a combination of at least two thereof.

[0029] Preferably, the auxiliary agent in the protective layer includes any one of an antioxidant, a light stabilizer, and a lubricant, or a combination of at least two of them.

[0030] Preferably, the antioxidant includes any one of β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate, pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate, tris(nonylphenyl) phosphite, and 3,5-di-tert-butyl-4-hydroxybenzylphosphonic acid distearyl or a combination of at least two thereof.

[0031] Preferably, the light stabilizer includes any one of bis(2,2,6,6-tetramethyl-4-piperidinyl) sebacate, poly(4-hydroxy-2,2,6,6-tetramethyl-1-piperidinethanol) succinate or poly-{[6-[(1,1,3,3-tetramethylbutyl)-imino]-1,3,5-triazine-2,4-diyl][2-(2,2,6,6-tetramethylpiperidinyl)-nitrogen]-hexylene-[4-(2,2,6,6-tetramethylpiperidinyl)-amino]} or a combination of at least two thereof.

[0032] Preferably, the lubricant includes any one of zinc stearate, oleamide, silicone, calcium stearate, stearic acid, polyethylene wax, EBS wax, and erucamide, or a combination of at least two thereof.

[0033] Preferably, the raw materials for preparing the intermediate core layer include the following components in parts by weight:

[0034]

[0035] Preferably, the amount of the water-blocking resin used in preparing the intermediate core layer can be 70 parts, 75 parts, 80 parts, 85 parts, 90 parts, 95 parts, 100 parts, etc., based on parts by weight.

[0036] Preferably, the amount of the water-blocking filler used in preparing the intermediate core layer can be 5 parts, 8 parts, 10 parts, 13 parts, 15 parts, 18 parts, 20 parts, 23 parts, 25 parts, 28 parts, 30 parts, etc., based on weight parts.

[0037] Preferably, the amount of the sensitizer used in the preparation of the intermediate core layer can be 0.1 parts, 0.3 parts, 0.5 parts, 0.8 parts, 1 parts, 1.3 parts, 1.5 parts, 1.8 parts, 2 parts, etc., based on the weight parts of the raw materials.

[0038] Preferably, the amount of the auxiliary agent used in the preparation of the intermediate core layer can be 0 parts, 0.1 parts, 0.3 parts, 0.5 parts, 0.8 parts, 1 parts, 1.3 parts, 1.5 parts, 1.8 parts, 2 parts, etc., based on the weight parts of the raw materials.

[0039] In the present invention, the middle core layer has excellent mechanical strength and water-blocking effect.

[0040] Preferably, the water-blocking resin includes any one of polyethylene resin, EVOH resin, PVDC resin, cycloolefin COC resin or modified polyethylene resin, or a combination of at least two thereof.

[0041] Preferably, the polyethylene resin in the water-blocking resin includes any one of LDPE, LLDPE, HDPE or MDPE, or a combination of at least two of them.

[0042] Preferably, the modified polyethylene resin in the water-blocking resin includes any one or a combination of at least two of ethylene-acrylate copolymer, polyethylene-maleic anhydride graft, ethylene-vinyl acetate copolymer, ethylene-octene copolymer, ethylene-butene copolymer, ethylene-acrylic acid copolymer, ethylene-butyl acrylate copolymer or POE-glycidyl acrylate graft.

[0043] Preferably, the water-blocking filler in the intermediate core layer includes any one of alumina, magnesium oxide, nano zeolite molecular sieve, modified diatomaceous earth, hollow glass microspheres, mica powder, talc, montmorillonite, modified montmorillonite, hydrotalcite, silica or modified silica, or a combination of at least two thereof.

[0044] Preferably, the sensitizer in the intermediate core layer includes any one of triallyl cyanurate (TAIC), tripropargyl cyanurate (TAC), trimethylolpropane trimethacrylate (TMPTMA), trimethylolpropane triacrylate (TMPTA), or a combination of at least two thereof.

[0045] Preferably, the auxiliary agent in the intermediate core layer includes any one of an antioxidant, a light stabilizer, and a lubricant, or a combination of at least two of them.

[0046] Preferably, the antioxidant includes any one of β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate, pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate, tris(nonylphenyl) phosphite, and 3,5-di-tert-butyl-4-hydroxybenzylphosphonic acid distearyl or a combination of at least two thereof.

[0047] Preferably, the light stabilizer includes any one of bis(2,2,6,6-tetramethyl-4-piperidinyl) sebacate, poly(4-hydroxy-2,2,6,6-tetramethyl-1-piperidinethanol) succinate or poly-{[6-[(1,1,3,3-tetramethylbutyl)-imino]-1,3,5-triazine-2,4-diyl][2-(2,2,6,6-tetramethylpiperidinyl)-nitrogen]-hexylene-[4-(2,2,6,6-tetramethylpiperidinyl)-amino]} or a combination of at least two thereof.

[0048] Preferably, the lubricant includes any one of zinc stearate, oleamide, silicone, calcium stearate, stearic acid, polyethylene wax, EBS wax, and erucamide, or a combination of at least two thereof.

[0049] Preferably, the raw materials for preparing the bonding layer include the following components in parts by weight:

[0050]

[0051] Preferably, the amount of polyethylene resin used in preparing the bonding layer can be 75 parts, 80 parts, 85 parts, 90 parts, 95 parts, etc., based on weight parts.

[0052] Preferably, the raw materials for preparing the bonding layer are measured in parts by weight, and the amount of the modified polyethylene resin used can be 1 part, 3 parts, 5 parts, 8 parts, 10 parts, 13 parts, 15 parts, 18 parts, 20 parts, etc.

[0053] Preferably, the amount of filler used in the preparation of the bonding layer can be 5 parts, 8 parts, 10 parts, 13 parts, 15 parts, etc., based on the weight of the raw materials.

[0054] Preferably, the amount of the sensitizer used in the preparation of the bonding layer can be 0.1 parts, 0.3 parts, 0.5 parts, 0.8 parts, 1 parts, 1.3 parts, 1.5 parts, 1.8 parts, 2 parts, etc., based on the weight parts of the raw materials.

[0055] Preferably, the raw materials for preparing the bonding layer are measured in parts by weight, and the amount of the auxiliary agent used can be 0 part, 0.1 part, 0.3 part, 0.5 part, 0.8 part, 1 part, 1.3 parts, 1.5 parts, 1.8 parts, 2 parts, etc.

[0056] In the present invention, the adhesive layer and the adhesive film have excellent adhesive properties.

[0057] Preferably, the polyethylene resin in the bonding layer includes any one of LDPE, LLDPE, HDPE or MDPE, or a combination of at least two thereof.

[0058] Preferably, the modified polyethylene resin in the bonding layer includes any one or a combination of at least two of ethylene-acrylate copolymer, polyethylene-maleic anhydride graft, ethylene-vinyl acetate copolymer, ethylene-octene copolymer, silicone-modified acrylic resin, silicone-modified resin, vinyl resin, ethylene-butene copolymer, ethylene / acrylic acid copolymer, ethylene-butyl acrylate copolymer or POE-glycidyl acrylate graft.

[0059] Preferably, the filler in the bonding layer includes any one of titanium dioxide, carbon black, perylene black, copper black, aluminum oxide, aluminum hydroxide, magnesium hydroxide, aluminum oxide, magnesium oxide, talcum powder, silicon dioxide, calcium carbonate, mica powder, barium sulfate, modified diatomaceous earth, pumice powder or modified diamond powder, or a combination of at least two thereof.

[0060] Preferably, the sensitizer in the bonding layer includes any one of triallyl cyanurate (TAIC), tripropargyl cyanurate (TAC), trimethylolpropane trimethacrylate (TMPTMA), and trimethylolpropane triacrylate (TMPTA), or a combination of at least two thereof.

[0061] Preferably, the auxiliary agent in the adhesive layer includes any one of an antioxidant, a light stabilizer, and a lubricant, or a combination of at least two of them.

[0062] Preferably, the antioxidant includes any one of β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate, pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate, tris(nonylphenyl) phosphite, and 3,5-di-tert-butyl-4-hydroxybenzylphosphonic acid distearyl or a combination of at least two thereof.

[0063] Preferably, the light stabilizer includes any one of bis(2,2,6,6-tetramethyl-4-piperidinyl) sebacate, poly(4-hydroxy-2,2,6,6-tetramethyl-1-piperidinethanol) succinate or poly-{[6-[(1,1,3,3-tetramethylbutyl)-imino]-1,3,5-triazine-2,4-diyl][2-(2,2,6,6-tetramethylpiperidinyl)-nitrogen]-hexylene-[4-(2,2,6,6-tetramethylpiperidinyl)-amino]} or a combination of at least two thereof.

[0064] Preferably, the lubricant includes any one of zinc stearate, oleamide, silicone, calcium stearate, stearic acid, polyethylene wax, EBS wax, and erucamide, or a combination of at least two thereof.

[0065] Preferably, the thickness of the protective layer is 100-200 μm, for example, 100 μm, 120 μm, 150 μm, 170 μm, 200 μm, etc.

[0066] Preferably, the thickness of the intermediate core layer is 100-200 μm, for example, 100 μm, 120 μm, 150 μm, 170 μm, 200 μm, etc.

[0067] Preferably, the thickness of the adhesive layer is 50-100 μm, for example, 50 μm, 60 μm, 70 μm, 90 μm, 100 μm, etc.

[0068] Preferably, when the solar cell back sheet has a single-layer structure, the raw materials for its preparation include the following components in parts by weight:

[0069] Water-blocking resin 70-90 parts;

[0070]

[0071] Preferably, when the solar cell back sheet has a single-layer structure, the amount of the water-blocking resin used in its preparation can be 70 parts, 75 parts, 80 parts, 85 parts, 90 parts, etc., based on the weight percentage of the raw materials used.

[0072] Preferably, when the solar cell back sheet has a single-layer structure, the amount of the modified polyethylene resin used in its preparation can be 1 part, 3 parts, 5 parts, 8 parts, 10 parts, 13 parts, 15 parts, etc., based on the weight parts of the raw materials.

[0073] Preferably, when the solar cell back sheet has a single-layer structure, the amount of the acrylate monomer used in its preparation can be 1 part, 3 parts, 5 parts, 8 parts, 10 parts, 13 parts, 15 parts, etc., based on the weight parts.

[0074] Preferably, when the solar cell back sheet has a single-layer structure, the amount of the water-blocking filler used in its preparation can be 5 parts, 10 parts, 15 parts, 20 parts, 25 parts, 30 parts, etc., based on the weight of the raw materials used.

[0075] Preferably, when the solar cell back sheet has a single-layer structure, the amount of the sensitizer used in its preparation raw materials can be 0.1 parts, 0.3 parts, 0.5 parts, 0.8 parts, 1 parts, 1.3 parts, 1.5 parts, 1.8 parts, 2 parts, etc., in terms of weight parts.

[0076] Preferably, when the solar cell back panel has a single-layer structure, the amount of the auxiliary agent used in its preparation raw materials can be 0 parts, 0.1 parts, 0.3 parts, 0.5 parts, 0.8 parts, 1 parts, 1.3 parts, 1.5 parts, 1.8 parts, 2 parts, etc., in terms of weight parts.

[0077] Preferably, the water-blocking resin in the single-layer structure includes any one of polyethylene resin, EVOH resin, PVDC resin, and cycloolefin COC resin, or a combination of at least two of them.

[0078] Preferably, the polyethylene resin in the water-blocking resin includes any one of LDPE, LLDPE, HDPE or MDPE, or a combination of at least two of them.

[0079] Preferably, the modified polyethylene resin in the single-layer structure includes any one of ethylene-acrylate copolymer, ethylene-methyl methacrylate copolymer, polyethylene-maleic anhydride graft, ethylene-vinyl acetate copolymer, ethylene-octene copolymer, ethylene-butene copolymer, ethylene-acrylic acid copolymer, ethylene-butyl acrylate copolymer or POE-glycidyl acrylate graft, or a combination of at least two thereof.

[0080] Preferably, the acrylic ester monomer in the single-layer structure includes any one of methyl acrylate, methyl methacrylate, hydroxyethyl acrylate, hydroxyethyl methacrylate, lauryl methacrylate or tripropylene glycol diacrylate, or a combination of at least two thereof.

[0081] Preferably, the water-blocking filler in the single-layer structure includes any one of alumina, magnesium oxide, nano-zeolite molecular sieve, modified diatomaceous earth, hollow glass microspheres, mica powder, talc, montmorillonite, modified montmorillonite, hydrotalcite, silica or modified silica, or a combination of at least two thereof.

[0082] Preferably, the sensitizer in the single-layer structure includes any one of triallyl cyanurate (TAIC), tripropargyl cyanurate (TAC), trimethylolpropane trimethacrylate (TMPTMA), and trimethylolpropane triacrylate (TMPTA), or a combination of at least two thereof.

[0083] Preferably, the auxiliary agent in the single-layer structure includes any one of an antioxidant, a light stabilizer, and a lubricant, or a combination of at least two of them.

[0084] Preferably, the antioxidant comprises one or a mixture of two or more of β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate, pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate, tris(nonylphenyl) phosphite, and 3,5-di-tert-butyl-4-hydroxybenzylphosphonic acid distearyl.

[0085] Preferably, the light stabilizer includes any one of bis(2,2,6,6-tetramethyl-4-piperidinyl) sebacate, poly(4-hydroxy-2,2,6,6-tetramethyl-1-piperidinethanol) succinate or poly-{[6-[(1,1,3,3-tetramethylbutyl)-imino]-1,3,5-triazine-2,4-diyl][2-(2,2,6,6-tetramethylpiperidinyl)-nitrogen]-hexylene-[4-(2,2,6,6-tetramethylpiperidinyl)-amino]} or a combination of at least two thereof.

[0086] Preferably, the lubricant includes any one of zinc stearate, oleamide, silicone, calcium stearate, stearic acid, polyethylene wax, EBS wax, and erucamide, or a combination of at least two thereof.

[0087] Preferably, the solar cell backplane is a white backplane, a black backplane or a transparent backplane.

[0088] Preferably, the reflectivity of the white backplane in the range of 385-1100 nm is >40%, for example 45%, 50%, 60%, 70%, 75%, 80%, 85%, 90%, 95%, etc., preferably >70%.

[0089] Preferably, the reflectivity of the black backplane in the range of 385-1100 nm is greater than 20%, such as 25%, 30%, 40%, 45%, 50%, 55%, 60%, etc., preferably greater than 40%.

[0090] Preferably, the light transmittance of the transparent backplane in the range of 385-1100 nm is greater than 70%, such as 75%, 80%, 85%, 90%, 95%, etc., preferably greater than 80%.

[0091] In a second aspect, the present invention provides a method for preparing a solar cell back sheet as described in the first aspect, wherein when the solar cell back sheet has a single-layer structure, the preparation method comprises the following steps:

[0092] The raw materials for preparing the solar cell back sheet are mixed, extruded through an extruder, and then pre-crosslinked to obtain the solar cell back sheet;

[0093] When the solar cell back sheet has a multi-layer structure, the preparation method thereof comprises the following steps:

[0094] The raw materials for preparing each layer are mixed respectively and placed in different screws of an extruder, co-extruded once through a co-extrusion die head, and then pre-cross-linked to obtain the solar cell back sheet.

[0095] In the preparation method provided by the present invention, the polyethylene is cross-linked by irradiation through co-extrusion by a screw extruder, thereby increasing the heat resistance, rigidity, hardness and stiffness of the overall back sheet. At the same time, the preparation process of the method is simple, the processing temperature is low, the energy consumption is reduced, the multi-layer (for example, three-layer, four-layer or five-layer) co-extrusion is formed, the glue compound is avoided, the fluorine-free, the environment is friendly, the process is simple, the process flow is greatly shortened, and the material cost and production cost are low.

[0096] Preferably, the processing temperature of the extruder is 150-180°C, for example, 150°C, 155°C, 160°C, 165°C, 170°C, 175°C, 180°C, etc.

[0097] Preferably, the co-extrusion method includes any one of biaxial stretching, uniaxial stretching, casting or calendering.

[0098] Preferably, the pre-crosslinking includes any one of ultraviolet light pre-crosslinking, thermal curing crosslinking, microwave crosslinking or radiation crosslinking, or a combination of at least two thereof, and the heat resistance, rigidity, hardness and stiffness of the overall backplane are increased by pre-crosslinking.

[0099] Preferably, the peel strength between the adhesive layer and the ethylene-vinyl acetate copolymer sheet is ≥120 N / cm.

[0100] Preferably, the water vapor permeability of the solar cell backsheet is ≤2g / m 2 ·day.

[0101] In a third aspect, the present invention provides an application of the solar cell back panel as described in the first aspect in a photovoltaic module.

[0102] Compared with the prior art, the present invention has the following beneficial effects:

[0103] (1) When the solar cell backsheet provided by the present invention has a multi-layer structure, the material structures between the layers are similar, the compatibility is excellent, and there is no risk of delamination. As a preferred embodiment, the linear low-density polyethylene content in the adhesive layer on the film side is not less than 50%, so that it has excellent adhesion with the encapsulation film, avoiding the risk of delamination between the backsheet and the film.

[0104] (2) The solar cell backplane provided by the present invention has a main resin of polyethylene and adopts a co-extrusion process. Compared with the traditional PET or PP material backplane, it has a lower processing temperature, lower than 180°C, which can save a lot of energy consumption. At the same time, the extremely simple multi-layer (for example, three-layer, four-layer or five-layer) co-extrusion processing technology avoids the use of adhesives and reduces the adhesive link that has a lot of pollution to the environment. At the same time, it simplifies the entire backplane production process and saves a lot of manpower and energy.

[0105] (3) The peel strength between the solar cell back sheet and the ethylene-vinyl acetate copolymer sheet provided by the present invention is ≥120N / cm, and the water vapor transmission rate is <2g / m 2 ·day. BRIEF DESCRIPTION OF THE DRAWINGS

[0106] Figure 1 A schematic structural diagram of a solar cell backplane provided in Example 1 of the present invention;

[0107] Among them, 1-protective layer, 2-intermediate core layer, 3-adhesive layer. DETAILED DESCRIPTION

[0108] The technical solution of the present invention is further described below by specific implementation methods. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0109] Example 1

[0110] In this embodiment, a solar cell back sheet with a three-layer structure is provided, and its structure is shown in FIG. Figure 1 As shown, it includes a protective layer 1, an intermediate core layer 2 and a bonding layer 3 which are arranged in sequence.

[0111] The raw materials and dosage (weight parts) of each layer are shown in the following table:

[0112]

[0113]

[0114] The preparation method comprises the following steps:

[0115] According to the above formula, the raw materials of each layer are mixed evenly and then added into three independent single-screw extruders of the same extruder respectively. The temperature of the screw extruder is 175°C. A three-layer co-extrusion die is used for extrusion molding. After cooling, traction and winding, a co-extruded backplane is obtained. After electron beam irradiation cross-linking, the irradiation dose is 150kGY to obtain the final co-extruded backplane product, that is, the solar cell backplane.

[0116] The thickness of each layer is as follows: protective layer 150 μm, intermediate core layer 180 μm, and bonding layer 70 μm.

[0117] Example 2

[0118] The difference between this embodiment and embodiment 1 is that the thickness of each layer is as follows: 120 μm for the protective layer, 200 μm for the intermediate core layer, and 70 μm for the bonding layer.

[0119] Example 3

[0120] The difference between this embodiment and embodiment 1 is that the thickness of each layer is as follows: 150 μm for the protective layer, 150 μm for the intermediate core layer, and 100 μm for the bonding layer.

[0121] Example 4

[0122] The difference between this embodiment and embodiment 1 is that the thickness of each layer is as follows: 200 μm for the protective layer, 150 μm for the intermediate core layer, and 100 μm for the bonding layer.

[0123] Example 5

[0124] The difference between this embodiment and embodiment 1 is that the thickness of each layer is as follows: 200 μm for the protective layer, 200 μm for the intermediate core layer, and 70 μm for the bonding layer.

[0125] Example 6

[0126] The difference between this embodiment and embodiment 1 is that the thickness of each layer is as follows: 120 μm for the protective layer, 200 μm for the intermediate core layer, and 80 μm for the bonding layer.

[0127] Example 7

[0128] The difference between this embodiment and embodiment 1 is that the raw materials and amounts of each layer are different, as shown in the following table:

[0129]

[0130] Example 8

[0131] The difference between this embodiment and embodiment 1 is that the raw materials and amounts of each layer are different, as shown in the following table:

[0132]

[0133] Example 9

[0134] In this embodiment, a solar cell back sheet with a single-layer structure is provided, and its preparation raw materials and usage (in parts by weight) are shown in the following table:

[0135]

[0136]

[0137] The preparation method comprises the following steps:

[0138] According to the above formula, the raw materials are mixed evenly and added to the extruder. The temperature of the screw extruder is 175°C. The die is used for extrusion molding. After cooling, traction and winding, a backplane is obtained. After electron beam irradiation cross-linking, the irradiation dose is 150kGY to obtain the final backplane product, that is, the solar cell backplane (thickness is 390μm) is obtained.

[0139] Comparative Example 1

[0140] This comparative example is a commercially available back sheet BO-L3, which is a weather-resistant PET+polyolefin layer structure.

[0141] Comparative Example 2

[0142] This comparative example is a commercially available backplane InshineT01, which has a fluorine film + PET + coating structure.

[0143] Comparative Example 3

[0144] The comparative example is a commercially available backplane Inshine201, which has a coating + PET + coating structure.

[0145] Comparative Example 4

[0146] This comparative example is a commercially available back sheet, which is a three-layer co-extruded PO back sheet, and the main resin is PP polypropylene resin.

[0147] Comparative Example 5

[0148] The only difference between this comparative example and Example 1 is that the LLDPE and HDPE in the protective layer are replaced by PP (80 parts, brand HJ800R).

[0149] Comparative Example 6

[0150] The only difference between this comparative example and Example 1 is that the amount of LLDPE in the adhesive layer is changed to 45 parts. The performance test of the solar cell backsheet provided in the example and the comparative example is carried out, and the test method is as follows: (1) Hardness: refer to GB / T3398-2008 test;

[0151] (2) Water vapor transmission rate: refer to GB / T 26253-2010 test;

[0152] (3) UV resistance: Tested in accordance with IEC 61215;

[0153] (4) Peel strength with EVA: tested according to ASTM D903;

[0154] (5) Heat resistance: Tested in accordance with GB / T 11026.8-2014.

[0155] The performance test results are shown in Table 1.

[0156] Table 1

[0157]

[0158]

[0159] It can be seen from Table 1 that, compared with the conventional commercially available backsheets in Comparative Examples 1-4, the solar cell backsheet provided by the present invention has good weather resistance, no powdering and cracking under UV radiation, excellent water barrier performance, and a water vapor transmission rate of less than 2g / m 2 day; good adhesion, peel strength with EVA film is above 120N / cm, and no delamination after aging.

[0160] Compared with Example 1, the solar cell back panels provided in Comparative Examples 5 and 6 all have powdering and cracking phenomena.

[0161] The applicant declares that the present invention uses the above-mentioned embodiments to illustrate the solar cell backsheet and its preparation method and application, but the present invention is not limited to the above-mentioned embodiments, that is, it does not mean that the present invention must rely on the above-mentioned embodiments to be implemented. Those skilled in the art should understand that any improvement of the present invention, equivalent replacement of the raw materials selected by the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A solar cell back sheet, characterized in that: The solar cell back sheet has a single-layer structure or a multi-layer structure; When the solar cell back sheet has a single-layer structure, its preparation raw materials include polyethylene resin and modified polyethylene resin; When the solar cell back sheet has a multi-layer structure, it includes a protective layer, an intermediate core layer and an adhesive layer arranged in sequence; The raw materials for preparing the protective layer and the bonding layer both include polyethylene resin and modified polyethylene resin.

2. The solar cell back sheet according to claim 1, characterized in that: The raw materials for preparing the protective layer include the following components in parts by weight: Preferably, the polyethylene resin in the protective layer includes any one of LDPE, LLDPE, HDPE or MDPE, or a combination of at least two thereof; Preferably, the modified polyethylene resin in the protective layer includes any one or a combination of at least two of ethylene-acrylate copolymer, ethylene-methyl methacrylate copolymer, polyethylene-maleic anhydride graft, ethylene-vinyl acetate copolymer, ethylene-octene copolymer, ethylene-butene copolymer, silicone-modified acrylic resin, silicone-modified resin, vinyl resin, ethylene-acrylic acid copolymer, ethylene-butyl acrylate copolymer or POE-glycidyl acrylate graft; Preferably, the acrylic acid ester monomer in the protective layer includes any one of methyl acrylate, methyl methacrylate, hydroxyethyl acrylate, hydroxyethyl methacrylate, lauryl methacrylate or tripropylene glycol diacrylate, or a combination of at least two thereof; Preferably, the filler in the protective layer includes any one of titanium dioxide, modified titanium dioxide, carbon black, perylene black, copper black, aluminum oxide, aluminum hydroxide, magnesium hydroxide, aluminum oxide, magnesium oxide, talcum powder, silicon dioxide, modified silicon dioxide, calcium carbonate, mica powder, barium sulfate, modified diatomaceous earth, pumice powder or modified diamond powder, or a combination of at least two thereof; Preferably, the sensitizer in the protective layer includes any one of triallyl cyanurate, tripropargyl cyanurate, trimethylolpropane trimethacrylate, and trimethylolpropane triacrylate, or a combination of at least two thereof; Preferably, the auxiliary agent in the protective layer includes any one of an antioxidant, a light stabilizer, and a lubricant, or a combination of at least two of them.

3. The solar cell back sheet according to claim 1 or 2, characterized in that: The raw materials for preparing the intermediate core layer include the following components in parts by weight: Preferably, the water-blocking resin comprises any one of polyethylene resin, EVOH resin, PVDC resin, cycloolefin COC resin or modified polyethylene resin, or a combination of at least two thereof; Preferably, the polyethylene resin in the water-blocking resin includes any one of LDPE, LLDPE, HDPE or MDPE, or a combination of at least two thereof; Preferably, the modified polyethylene resin in the water-blocking resin includes any one or a combination of at least two of ethylene-acrylate copolymer, polyethylene-maleic anhydride graft, ethylene-vinyl acetate copolymer, ethylene-octene copolymer, ethylene-butene copolymer, ethylene-acrylic acid copolymer, ethylene-butyl acrylate copolymer or POE-glycidyl acrylate graft; Preferably, the water-blocking filler in the intermediate core layer includes any one or a combination of at least two of alumina, magnesium oxide, nano-zeolite molecular sieve, modified diatomaceous earth, hollow glass microspheres, mica powder, talc, montmorillonite, modified montmorillonite, hydrotalcite, silicon dioxide or modified silicon dioxide; Preferably, the sensitizer in the intermediate core layer includes any one of triallyl cyanurate, tripropargyl cyanurate, trimethylolpropane trimethacrylate, and trimethylolpropane triacrylate, or a combination of at least two thereof; Preferably, the auxiliary agent in the intermediate core layer includes any one of an antioxidant, a light stabilizer, and a lubricant, or a combination of at least two of them.

4. The solar cell back sheet according to any one of claims 1 to 3, characterized in that: The raw materials for preparing the bonding layer include the following components in parts by weight: Preferably, the polyethylene resin in the bonding layer includes any one of LDPE, LLDPE, HDPE or MDPE, or a combination of at least two thereof; Preferably, the modified polyethylene resin in the adhesive layer includes any one or a combination of at least two of ethylene-acrylate copolymer, polyethylene-maleic anhydride graft, ethylene-vinyl acetate copolymer, ethylene-octene copolymer, silicone-modified acrylic resin, silicone-modified resin, vinyl resin, ethylene-butene copolymer, ethylene / acrylic acid copolymer, ethylene-butyl acrylate copolymer or POE-glycidyl acrylate graft; Preferably, the filler in the bonding layer includes any one or a combination of at least two of titanium dioxide, carbon black, perylene black, copper black, aluminum oxide, aluminum hydroxide, magnesium hydroxide, aluminum oxide, magnesium oxide, talcum powder, silicon dioxide, calcium carbonate, mica powder, barium sulfate, modified diatomaceous earth, pumice powder or modified diamond powder; Preferably, the sensitizer in the bonding layer includes any one of triallyl cyanurate, tripropargyl cyanurate, trimethylolpropane trimethacrylate, and trimethylolpropane triacrylate, or a combination of at least two thereof; Preferably, the auxiliary agent in the adhesive layer includes any one of an antioxidant, a light stabilizer, and a lubricant, or a combination of at least two of them.

5. The solar cell back sheet according to any one of claims 1 to 4, characterized in that: The thickness of the protective layer is 100-200 μm; Preferably, the thickness of the intermediate core layer is 100-200 μm; Preferably, the thickness of the adhesive layer is 50-100 μm.

6. The solar cell back sheet according to claim 1, characterized in that: When the solar cell back sheet has a single-layer structure, the raw materials for its preparation include the following components in parts by weight:

7. The solar cell back sheet according to claim 6, characterized in that: The water-blocking resin in the single-layer structure includes any one of polyethylene resin, EVOH resin, PVDC resin, and cycloolefin COC resin, or a combination of at least two thereof; Preferably, the polyethylene resin in the water-blocking resin includes any one of LDPE, LLDPE, HDPE or MDPE, or a combination of at least two thereof; Preferably, the modified polyethylene resin in the single-layer structure includes any one of ethylene-acrylate copolymer, ethylene-methyl methacrylate copolymer, polyethylene-maleic anhydride graft, ethylene-vinyl acetate copolymer, ethylene-octene copolymer, ethylene-butene copolymer, ethylene-acrylic acid copolymer, ethylene-butyl acrylate copolymer or POE-glycidyl acrylate graft, or a combination of at least two thereof; Preferably, the acrylic ester monomer in the single-layer structure includes any one of methyl acrylate, methyl methacrylate, hydroxyethyl acrylate, hydroxyethyl methacrylate, lauryl methacrylate or tripropylene glycol diacrylate, or a combination of at least two thereof; Preferably, the water-blocking filler in the single-layer structure includes any one or a combination of at least two of alumina, magnesium oxide, nano-zeolite molecular sieve, modified diatomaceous earth, hollow glass microspheres, mica powder, talc, montmorillonite, modified montmorillonite, hydrotalcite, silicon dioxide or modified silicon dioxide; Preferably, the sensitizer in the single-layer structure includes any one of triallyl cyanurate, tripropargyl cyanurate, trimethylolpropane trimethacrylate, and trimethylolpropane triacrylate, or a combination of at least two thereof; Preferably, the auxiliary agent in the single-layer structure includes any one of an antioxidant, a light stabilizer, and a lubricant, or a combination of at least two of them.

8. The solar cell back sheet according to any one of claims 1 to 7, characterized in that: The solar cell backplane is a white backplane, a black backplane or a transparent backplane; Preferably, the reflectivity of the white backplane in the range of 385-1100 nm is >40%, preferably >70%; Preferably, the reflectivity of the black backplane in the range of 385-1100 nm is >20%, preferably >40%; Preferably, the light transmittance of the transparent backplane in the range of 385-1100 nm is greater than 70%, preferably greater than 80%.

9. A method for preparing a solar cell back sheet according to any one of claims 1 to 8, characterized in that: When the solar cell back sheet has a single-layer structure, the preparation method thereof comprises the following steps: The raw materials for preparing the solar cell back sheet are mixed, extruded through an extruder, and then pre-crosslinked to obtain the solar cell back sheet; When the solar cell back sheet has a multi-layer structure, the preparation method thereof comprises the following steps: The raw materials for preparing each layer are mixed respectively and placed in different screws of an extruder, co-extruded once through a co-extrusion die head, and then pre-cross-linked to obtain the solar cell back sheet; Preferably, the processing temperature of the extruder is 150-180°C; Preferably, the co-extrusion method includes any one of biaxial stretching, uniaxial stretching, casting or calendering; Preferably, the pre-crosslinking includes any one of ultraviolet light pre-crosslinking, heat curing crosslinking, microwave crosslinking or radiation crosslinking, or a combination of at least two thereof.

10. Use of the solar cell back sheet according to any one of claims 1 to 8 in a photovoltaic module.

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