CN104505411A - Coated type solar battery backboard - Google Patents

Abstract

The invention relates to a coated solar battery back plate, at least one side of a substrate is coated with a first weather-resistant layer, and the first weather-resistant layer is coated with a second weather-resistant layer. The coating-type back sheet produced according to the invention has excellent appearance and excellent weather resistance. After double 85% damp heat aging, the coating has uniform appearance, no pulverization, and high adhesion.

Description

A kind of coating type solar cell back sheet

technical field

The patent of the present invention relates to the technical field of solar cells, in particular to a coated solar cell backplane.

Background technique

As a green alternative to traditional methods of electricity production, photovoltaic cell modules are used to generate electricity from the sun. Photovoltaic modules are assembled from various semiconductor element systems and must be protected to reduce the impact and damage of environmental effects such as moisture, oxygen and ultraviolet rays. Photovoltaic cell modules are generally made of glass, battery silicon wafers, EVA, and backsheet materials by hot pressing. Therefore, backsheets with excellent electrical insulation, interlayer bonding strength, weather resistance, UV resistance, and moisture resistance are used in Photovoltaic modules play an important protective role.

The traditional backsheet production method is formed by attaching fluoropolymer film on both sides of PET. This production method significantly improves the service life of the component. However, tight adhesion between fluoropolymer films and polymeric substrate materials that does not detach after years of outdoor exposure is difficult to achieve. In the prior art, the coating method can also be used to produce the back sheet. However, the current general coating design has the hidden danger that the coating partly falls off from the PET after damp heat aging, which affects the service life of the solar battery back sheet.

Contents of the invention

The technical problem to be solved by the present invention is to provide a coated solar battery back sheet, which has excellent weather resistance by coating two layers of fluorine-containing coatings. At the same time, through the coating design, it is guaranteed that the coating has a uniform appearance, no chalking phenomenon, and high adhesion after double 85% humidity and heat aging.

The technical scheme adopted by the patent of the present invention is:

A coating-type solar cell back sheet, at least one side of a substrate is coated with a first weather-resistant layer, and a second weather-resistant layer is coated on the top of the first weather-resistant layer, the first weather-resistant layer and the second weather-resistant layer are mainly It is composed of 25-40 parts by weight of fluorocarbon resin containing crosslinkable and curable functional groups, 20-35 parts by weight of inorganic filler, 4-8 parts by weight of cross-linking agent, and 35-55 parts by weight of solvent. The first weather-resistant layer also contains 1-5 parts by weight of polyester resin.

In the coating-type solar battery back sheet, the average particle size of the inorganic filler in the first weather-resistant layer and the second weather-resistant layer is 0.1 μm to 3.0 μm.

In the coating-type solar battery back sheet, the thickness of the first weather-resistant layer is 10 μm-20 μm, and the thickness of the second weather-resistant layer is 3 μm-10 μm.

In the above-mentioned coated solar cell back sheet, the fluorocarbon resin containing crosslinkable curable functional groups is a perfluoroolefin polymer containing crosslinkable curable functional groups, and the fluorocarbon resin containing crosslinkable curable functional groups is chlorotrifluoroethylene (CTFE) ) unit-based CTFE-based polymers, (VdF)-based polymers containing cross-linkable curable functional groups mainly composed of vinylidene fluoride (VdF) units, and those containing cross-linkable curable functional groups mainly composed of fluoroalkyl units The main body of the fluoroalkyl-containing polymer.

In the coating type solar cell backsheet, the cross-linkable curable functional group is introduced into the fluorine-containing polymer through copolymerization of the monomer containing the cross-linkable functional group. The cross-linkable curable functional groups are hydroxyl, carboxyl and amino groups.

In the coating-type solar cell backsheet, the crosslinking agent is one or more of isocyanate-based curing agents, melamine resins, ammonia-based curing agents, and epoxy-based curing agents. The following crosslinking agent is preferred: one of melamine resin, hexamethylene diisocyanate polymer, hexamethylene diisocyanate trimer, isophorone diisocyanate polymer, hexamethylene diisocyanate biuret or Several mixtures.

For the above-mentioned coated solar battery back sheet, the solvent is one or more of toluene, butanone, ethyl acetate, butyl acetate, and propylene glycol methyl ether acetate.

The beneficial effects of the present invention are:

The coating type solar battery back plate is obtained by using the invention, and the back plate has excellent weather resistance performance by coating two layers of fluorine-containing coatings. At the same time, through the coating design, it is guaranteed that the coating has a uniform appearance, no chalking phenomenon, and high adhesion after double 85% humidity and heat aging.

Description of drawings

Fig. 1 is the structural representation of coated solar cell back sheet of the present invention;

Fig. 2 is a schematic diagram of another structure of the present invention.

The symbols in the figure are represented as: 1. base material; 2. first weather-resistant layer; 3. second weather-resistant layer.

Detailed ways

The coated solar battery back sheet of the present invention is to coat the first weather-resistant layer 2 on one side of the base material, coat the second weather-resistant layer 3 on the first weather-resistant layer, and solidify to form a film; The first weather-resistant layer 2 and the second weather-resistant layer 3 are coated again in the same steps, and cured to form a film to obtain a coated solar battery back sheet.

The substrate generally used for coated solar cell backsheets is polyester, for example, it can be polyethylene terephthalate (PET), polyethylene naphthalate (PEN) or their bilayer co- extrusion product. Depending on the application, the substrate can be transparent, white or black.

In the fluoropolymer layer of the present invention, the coating solution of the fluoropolymer layer is first prepared, the coating solution contains fluorocarbon resin, crosslinking agent, inorganic filler, and the viscosity is adjusted to a suitable coating level by a solvent. scope.

The polyester resin used in the present invention is an amorphous polyester with a glass transition temperature lower than 80°C.

The coated solar battery back sheet provided by the present invention can be prepared by the following method:

The base material is unfolded, and the coating solution for the fluoropolymer layer is coated on its surface, and then cured to obtain a solar battery back sheet.

In the present invention, the fluoropolymer layer can be coated on the substrate by methods such as dip coating, air knife coating, knife coating, gravure coating, and slit coating.

The present invention will be further described below through specific examples, but the embodiments of the present invention are not limited thereto.

Example 1

Add 100 grams of butanone and 175 grams of ethyl acetate into a container equipped with a stirring device, start stirring, and mix 125 grams of hydroxyl-containing perfluoroolefin polymers, 100 grams of titanium dioxide powder, and 5 grams of polyester resin and 20 g of hexamethylene diisocyanate trimer were sequentially added to the solvent, ground and stirred for 60 minutes to prepare the fluoropolymer layer coating solution (a).

Add 100 grams of methyl ethyl ketone and 175 grams of ethyl acetate into a container equipped with a stirring device, start stirring, and mix 125 grams of perfluoroolefin polymers containing hydroxyl groups, 100 grams of titanium dioxide powder and 20 grams of hexamethylene Add the trimer of diisocyanate to the solvent in sequence, grind and stir for 60 minutes, and prepare the coating solution (b) for the fluoropolymer layer.

Apply the coating liquid (a) on the PET substrate by the doctor blade coating method, and dry it with hot air to obtain a first weather-resistant layer with a thickness of 10 μm. Apply the coating liquid (b) on the first weather-resistant layer and cure it. A coated solar cell back sheet with a thickness of the second weather-resistant layer of 20 μm was obtained.

Coating the other side of the base material according to the above steps to obtain a coated solar battery back sheet coated on both sides. Its performance can be seen in Table 1.

Example 2

Add 60 grams of butyl acetate and 125 grams of methyl ethyl ketone into a container equipped with a stirring device, start stirring, and mix 175 grams of CTFE-based polymers mainly containing hydroxyl-containing chlorotrifluoroethylene (CTFE) units, 100 grams of Titanium dioxide powder, 5 grams of polyester resin and 40 grams of isophorone diisocyanate polymer were sequentially added to the solvent, ground and stirred for 60 minutes to prepare the fluoropolymer layer coating liquid (a).

Add 60 grams of butyl acetate and 125 grams of methyl ethyl ketone into a container equipped with a stirring device, start stirring, and mix 175 grams of CTFE-based polymers mainly containing hydroxyl-containing chlorotrifluoroethylene (CTFE) units, 100 grams of Titanium dioxide powder and 40 grams of isophorone diisocyanate polymer were sequentially added to the solvent, ground and stirred for 60 minutes to prepare the fluoropolymer layer coating solution (b).

Apply the coating liquid (a) on the PET substrate by the doctor blade coating method, and dry it with hot air to obtain a first weather-resistant layer with a thickness of 10 μm. Apply the coating liquid (b) on the first weather-resistant layer and cure it. The obtained thickness of the second weather-resistant layer is 20 μm.

Coating the other side of the base material according to the above steps to obtain a coated solar battery back sheet coated on both sides. Its performance can be seen in Table 1.

Example 3

Add 100 grams of butanone and 75 grams of propylene glycol methyl ether acetate into a container equipped with a stirring device, start stirring, and mix 200 grams of hydroxyl-containing perfluoroolefin polymers, 175 grams of titanium dioxide powder, and 10 grams of poly The ester resin and 35 g of hexamethylene diisocyanate trimer were sequentially added to the solvent, ground and stirred for 60 minutes to prepare the fluoropolymer layer coating liquid (a).

Add 100 grams of butanone and 75 grams of propylene glycol methyl ether acetate into a container equipped with a stirring device, start stirring, and mix 200 grams of perfluoroolefin polymers containing hydroxyl groups, 175 grams of titanium dioxide powder and 35 grams of six The methylene diisocyanate trimer was sequentially added to the solvent, ground and stirred for 60 minutes to prepare the fluorine-containing polymer layer coating solution (b).

Apply the coating liquid (a) on the PET substrate by the doctor blade coating method, and dry it with hot air to obtain a first weather-resistant layer with a thickness of 20 μm. Apply the coating liquid (b) on the first weather-resistant layer and cure it. A coated solar cell back sheet with a thickness of the second weather-resistant layer of 23 μm was obtained.

Coating the other side of the base material according to the above steps to obtain a coated solar battery back sheet coated on both sides. Its performance can be seen in Table 1.

Example 4

Add 100 grams of butyl acetate and 100 grams of methyl ethyl ketone into a container equipped with a stirring device, start stirring, and mix 150 grams of CTFE-based polymers mainly containing hydroxyl-containing chlorotrifluoroethylene (CTFE) units, 125 grams of Titanium dioxide powder, 15 grams of polyester resin and 25 grams of isophorone diisocyanate polymer were sequentially added into the solvent, ground and stirred for 60 minutes to prepare the fluoropolymer layer coating liquid (a).

Add 100 grams of butyl acetate and 100 grams of methyl ethyl ketone into a container equipped with a stirring device, start stirring, and mix 150 grams of CTFE-based polymers mainly containing hydroxyl-containing chlorotrifluoroethylene (CTFE) units, 125 grams of Titanium dioxide powder and 25 grams of isophorone diisocyanate polymer were sequentially added to the solvent, ground and stirred for 60 minutes to prepare the fluoropolymer layer coating liquid (b).

Apply the coating liquid (a) on the PET substrate by the doctor blade coating method, and dry it with hot air to obtain a first weather-resistant layer with a thickness of 20 μm. Apply the coating liquid (b) on the first weather-resistant layer and cure it. A coated solar cell back sheet with a thickness of the second weather-resistant layer of 23 μm was obtained.

Coating the other side of the base material according to the above steps to obtain a coated solar battery back sheet coated on both sides. Its performance can be seen in Table 1.

Example 5

Add 150 grams of butanone and 50 grams of propylene glycol methyl ether acetate into a container equipped with a stirring device, start stirring, and mix 200 grams of hydroxyl-containing perfluoroolefin polymers, 150 grams of titanium dioxide powder, and 25 grams of poly The ester resin and 35 g of hexamethylene diisocyanate trimer were sequentially added to the solvent, ground and stirred for 60 minutes to prepare the fluoropolymer layer coating solution (a).

Add 150 grams of butanone and 50 grams of propylene glycol methyl ether acetate into a container equipped with a stirring device, start stirring, and mix 200 grams of perfluoroolefin polymers containing hydroxyl groups, 150 grams of titanium dioxide powder and 35 grams of six The methylene diisocyanate trimer was sequentially added to the solvent, ground and stirred for 60 minutes to prepare the fluorine-containing polymer layer coating solution (b).

Apply the coating liquid (a) on the PET substrate by the doctor blade coating method, and dry it with hot air to obtain a first weather-resistant layer with a thickness of 15 μm. Apply the coating liquid (b) on the first weather-resistant layer and cure it. A coated solar battery back sheet with a thickness of the second weather-resistant layer of 20 μm was obtained.

According to the above steps, coating on the other side of the substrate to obtain a coated solar battery back sheet coated on both sides, the performance of which is measured is shown in Table 1.

comparative example

Add 72.5 grams of propylene glycol methyl ether acetate, 45 grams of butyl acetate in a container equipped with a stirring device, start stirring, and mix 225 grams of hydroxyl-containing perfluoroolefin polymers, 125 grams of titanium dioxide powder and 45 grams of Amino resins were sequentially added to the solvent, ground and stirred for 60 minutes to obtain a fluoropolymer layer coating solution, which was coated on one side of the PET substrate and cured to obtain a comparative sample with a dry thickness of 25 μm.

Get a comparison sample. Its performance can be seen in Table 1.

Table 1: Performance Tests

Performance evaluation method:

1. Coating adhesion test

Test according to GB/T 9286-1998.

2. Appearance

Visual inspection under natural light, if the coating film has no blooming, pinholes, cracking, foaming, and powdering, it is "uniform and normal".

Claims (7)

1. an application type solar cell backboard, the first weathering layer (2) is scribbled at least one side of base material (1), the second weathering layer (3) is scribbled on the first weathering layer (2), it is characterized in that, described first weathering layer (2) and fluorocarbon resin 25 ~ 40 weight portion of the second weathering layer (3) mainly containing cross-linkable solidifying functional group, inorganic filler 20 ~ 35 weight portion, crosslinking agent 4 ~ 8 weight portion, solvent 35 ~ 55 weight portion, described first weathering layer (2) also comprises mylar 1-5 weight portion.

2. application type solar cell backboard according to claim 1, it is characterized in that, described first weathering layer (2), the second weathering layer (3) inorganic filler average grain diameter are 0.1 μm ~ 3.0 μm.

3. application type solar cell backboard according to claim 2, it is characterized in that, described first weathering layer (2) thickness is 10 μm ~ 20 μm, and the thickness of the second weathering layer (3) is 3 μm ~ 10 μm.

4. application type solar cell backboard according to claim 3, it is characterized in that, the described fluorocarbon resin containing cross-linkable solidifying functional group is the perfluoroolefine base polymer containing cross-linkable solidifying functional group, containing cross-linkable solidifying functional group based on the CTFE based polymer of chlorotrifluoroethylene unit, the VdF based polymer based on vinylidene fluoride units containing cross-linkable solidifying functional group, containing cross-linkable solidifying functional group based on fluoro-alkyl unit containing the polymer of fluoro-alkyl.

5. application type solar cell backboard according to claim 4, it is characterized in that, the monomer containing crosslinkable functionality is incorporated in fluoropolymer by copolymerization by described cross-linkable solidifying functional group, and described cross-linkable solidifying functional group is hydroxyl, carboxyl, amino.

6. application type solar cell backboard according to claim 5, is characterized in that, described crosslinking agent is one or more in isocyanate-based curing agent, melmac, ammonia system curing agent, epoxy curing agent.

7. application type solar cell backboard according to claim 6, it is characterized in that, described solvent is one or more in toluene, butanone, ethyl acetate, butyl acetate, 1-Methoxy-2-propyl acetate.