KR101339446B1 - Back Sheet for Solar Cell and Method for Fabricating The Same - Google Patents

Abstract

The present invention is to provide a solar cell back sheet and a method for manufacturing the same, which can simplify the process and reduce the manufacturing cost, and can improve physical properties such as heat resistance, moisture resistance, and mechanical strength. To this end, the present invention, the first layer having a first base film layer, a functional coating layer formed on the upper surface of the first base film layer, and a barrier layer formed on the back surface of the first base film layer to prevent moisture permeation and; A second layer having a second base film layer, an alumina deposition layer formed on an upper surface of the twenty-first base film layer, and an EVA adhesion layer formed on a rear surface of the second base film layer; It provides a back sheet for a solar cell comprising a; adhesive layer interposed between the first layer and the second layer. On the other hand, the present invention, to form a first layer by performing a first step of forming a functional coating layer on the upper surface of the first base film layer, and a second process of coating a barrier layer for preventing moisture permeability on the back of the first base film layer Making a step; Depositing alumina (Al ₂ O ₃ ) on the second base film to form an alumina (Al ₂ O ₃ ) deposition layer; Bonding a second base film on which alumina is deposited and a barrier layer constituting the first layer through a UV curable adhesive; It provides a solar cell back sheet manufacturing method comprising a; forming an EVA adhesion layer on the back of the second base film.

Description

Backsheet for Solar Cell and Method for Fabrication thereof {Back Sheet for Solar Cell and Method for Fabricating The Same}

The present invention relates to a solar cell back sheet, and more particularly, to a back sheet for protecting the back surface of a solar cell, the solar cell back sheet having excellent physical properties such as hardness, durability, weather resistance and heat resistance, and excellent adhesion. It relates to a manufacturing method.

In general, a solar cell module is a semiconductor device that converts light energy into electrical energy using a photoelectric effect, and has recently been in the spotlight for being pollution-free, noiseless, and infinite supply energy.

In particular, the Tokyo Protocol, which regulates greenhouse gas emissions such as carbon dioxide and methane gas, came into force on February 16, 2005 to prevent global warming, and fossil fuels in Korea have more than 80% of their energy sources. As an alternative to overcoming fundamental problems, we are focusing on renewable energy, and solar energy is one of the important alternative energy sources.

The technology of converting solar energy into electrical energy using a medium called a solar cell module has no mechanical and chemical effects in the process of converting solar energy into electrical energy. It is long, safe and environmentally friendly.

Such solar cell modules are typically laminated with tempered glass, upper EVA (ethylene vinyl acetate) emulsion, solar cell (Cell), EVA film, and back sheet (sequentially stacked), and the laminated modules are hot pressed under vacuum. It is prepared by laminating treatment. Here, the backsheet is a material having excellent durability that can withstand high temperatures and humidity in order to extend the life of the solar cell module while at the same time serves to waterproof, insulate and block the solar cell at the rear of the module. It is composed.

 In general, the sheet used for packaging the solar cell should use a back sheet having excellent weather resistance and durability so as to stably protect the solar cell even when exposed to the external environment for more than 20 years.

To this end, as shown in FIG. 1, conventionally, fluorine resin films such as polyvinylfluoride (PVF) or polyvinyldifluoride (PVDF) were mainly used in the outermost and innermost layers of the backsheet.

However, the conventional back sheet has a limitation in general use due to the disadvantage that the fluororesin films used for the outermost layer and the innermost layer are expensive and the purchase conditions are limited. In other words, the existing back sheet (Back Sheet) is a situation that is mostly dependent on the import is quite expensive and there is a problem that the supply amount is small.

In addition, the conventional backsheet using the fluororesin film has a problem in that the moisture resistance and the mechanical strength are poor in terms of physical properties and require a separate treatment or a separate additional structure.

In addition, the conventional back sheet has been using aluminum foil (aluminum foil) having a high electrical insulation as the electrical insulation layer, and the innermost layer is also finished using a fluororesin film, such a structure is complicated and multi-step process and production cost There is a disadvantage of being high.

Therefore, there is an urgent need for a new solar cell backsheet that has excellent durability, weather resistance, high mechanical strength, and can simplify the process while reducing manufacturing costs and improve the productivity and quality of the solar cell module. It is true.

Republic of Korea Patent Publication No. 10-2010-0089038 (2010.08.11) Republic of Korea Patent Publication No. 10-2010-0105505 (2010.09.29)

The present invention has been made to solve the above problems, and in the back sheet for protecting the back surface of the solar cell, it is possible to simplify the process and reduce the manufacturing cost, while simultaneously using organic and inorganic materials It is an object of the present invention to provide a solar cell back sheet and a method of manufacturing the same, by applying an organic-inorganic hybrid technology to improve physical properties such as heat resistance, moisture resistance, and high mechanical strength.

The present invention to achieve the above object, the first base film layer,

A functional coating layer formed on an upper surface of the first base film layer, and

A first layer having a barrier layer formed on a rear surface of the first base film layer to prevent moisture permeation;

Second base film layer,

An alumina deposition layer formed on an upper surface of the second base film layer, and

A second layer having an EVA adhesion layer formed on a rear surface of the second base film layer;

An adhesive layer interposed between the first layer and the second layer; there is provided a solar cell back sheet.

At this time, the first base film layer and the second base film layer, characterized in that made of any one of a polyethylene (terephthalate) film, a PC (polycarbonate) film, a polyimide (PI) film, a polyethylenenaphthalate (PEN) film.

The functional coating layer is composed of a UV curable resin, a functional organic and inorganic filler, and a physical property improving additive.

And, the EVA layer is characterized in that made of LLDPE (inear low-density polyethylene).

In addition, the adhesive layer is a solar cell back sheet, characterized in that made of an ultraviolet curable adhesive.

On the other hand, according to another aspect of the present invention for achieving the above object, the first step of forming a functional coating layer on the upper surface of the first base film layer, and the barrier layer for preventing moisture permeation on the back of the first base film layer Performing a second process to form a first layer;

Depositing alumina (Al ₂ O ₃ ) on the second base film to form an alumina (Al ₂ O ₃ ) deposition layer;

Bonding a second base film on which alumina is deposited and a barrier layer constituting the first layer through a UV curable adhesive;

Forming an EVA adhesion layer on the back of the second base film is provided a solar cell back sheet manufacturing method characterized in that it comprises a.

Solar cell back sheet according to the present invention has the following effects.

First, according to the present invention, by replacing the fluorine-based film such as PVF, PVDF with a coating layer containing fluorine, the manufacturing cost of the backsheet is reduced.

Second, according to the present invention, the backsheet is composed of two film layers, thereby reducing the backsheet manufacturing process and cost.

Third, according to the present invention, the coating layer and the adhesive layer is made of a UV-curable chemical (chemical) has the effect of strengthening the moisture permeability with the filler to prevent moisture permeation.

Fourthly, according to the present invention, it is composed of two layers to which an organic-inorganic hybrid technology (a technology that simultaneously implements processing and mechanical and chemical properties by using organic and inorganic materials simultaneously) is applied, and has properties such as heat resistance, moisture resistance, and mechanical strength improvement. Implementation is possible.

Fifth, according to the present invention, by using alumina deposition instead of aluminum foil to reduce the cost, and further improve the physical properties of heat resistance, moisture resistance, mechanical strength along with electrical insulation.

Sixth, the existing backsheet was expensive and the supply amount was limited, so the purchase conditions were limited, but the backsheet of the present invention can be lowered because the production cost is lowered.

Seventh, according to the present invention, it is changed to a structure that does not need to use an electrically insulating aluminum foil and a fluorine resin film, it is possible to simplify the process, to reduce the production cost so that the supply is made smoothly can do.

1 is a schematic diagram showing a cross-sectional structure of the existing back sheet
Figure 2 is a schematic diagram showing a backsheet cross-sectional structure of the present invention 1 is a front view

Hereinafter, with reference to the accompanying drawings, the specific content for the practice of the present invention will be described in detail as follows.

2 is a schematic view showing a cross-sectional configuration of a solar cell back sheet according to the present invention, referring to this, the solar cell back sheet (B) of the present invention, the first layer and the second layer attached to the back, and It is roughly classified into an adhesive layer which serves to firmly attach the first layer and the second layer.

In this case, the first layer is a component, the first base film layer 2, the functional coating layer (1) formed on the upper surface of the first base film layer 2, and the first base film layer (2) Barrier layer (3) is formed on the back of the) to prevent moisture permeation.

The second layer is a component thereof, and includes a second base film layer 6, an alumina deposition layer 5 formed on an upper surface of the second base film layer, and a rear surface of the second base film layer 6. It is provided with an EVA adhesion layer 7 formed on.

Meanwhile, the first base film layer 2 and the second base film layer 6 may be made of any one of polyethylene terephthalate (PET) film, polycarbonate (PC) film, polyimide (PI) film, and polyethylenenaphthalate (PEN) film. In addition, since the physical properties of the transparency, heat resistance, moisture resistance is relatively excellent compared to the other films, PET film is mainly used, preferably heat-resistant low oligomer PET film having a high transparency of 90% or more transmittance.

In addition, the functional coating layer 1 is composed of a UV-curable resin, a functional organic-inorganic filler and a physical property improving additive.

In addition, the EVA adhesion layer 7 is made of LLDPE (inear low-density polyethylene).

In addition, the adhesive layer 4 serves to firmly attach the first layer and the second layer, and an ultraviolet curable adhesive, a thermosetting oil adhesive, a thermosetting aqueous adhesive, and a hotmelt adhesive may be used. Preferably, an ultraviolet (UV) curable adhesive is used.

In the backsheet B of the present invention configured as described above, the alumina deposition layer 5 not only improves electrical insulation but also improves mechanical properties such as heat resistance, cold resistance, and fracture resistance.

That is, discharge may occur in the process of generating and accumulating electrical energy in a solar cell module. At this time, when the amount of the discharged electric energy increases, solar cell breakdown occurs. To prevent this, an electrical insulation layer should be formed. Conventionally, aluminum foil is often used, but because it is expensive, in order to reduce the manufacturing cost, alumina (Al ₂ O ₃ ) was deposited on the second base film by vacuum deposition to form an electrical insulation layer.

Such an aluminum oxide deposited layer not only improves electrical insulation but also improves mechanical properties such as heat resistance, cold resistance, and fracture resistance.

On the other hand, the back sheet (B) is finally attached to the EVA layer of the solar cell module, but when attached to the untreated PET film, the adhesion is low and the cracks in the adhesion layer with time This adversely affects the life of the solar cell module. Because of this, the layers must be subjected to a separate pretreatment process to maintain a firm attachment.

In other words, mainly LLDPE (Linear low-density polyethylene), EVA-based hotmelt adhesive or TPU (Thermal polyurethane) is coated by T-die coating method, which is a kind of extrusion coating method, preferably LLDPE with low cost and good adhesion properties is used.

For reference, the solar cell backsheet (B) of the present invention configured as described above may be divided into an outermost layer in contact with the external environment, an intermediate layer, and an innermost layer in contact with the EVA layer of the solar cell. A first base film layer 2 having transparency, heat resistance, and moisture resistance, and a functional coating layer 1 exposed to the external environment, wherein the intermediate layer is a barrier layer 3 for preventing moisture permeability, and an adhesive layer having UV blocking effect. 4) and an alumina deposition layer 5 having electrical insulation, and the innermost layer is composed of a second base film layer 6 having transparency, heat resistance, and moisture resistance, and an EVA adhesion layer 7 for adhesion of EVA. do.

The manufacturing process of the solar cell back sheet (B) of the present invention configured as described above is as follows.

First, a process (first process) of forming a functional coating layer 1 on the upper surface of the first base film layer 2 is performed.

Subsequently, a process (second process) of coating the barrier layer 3 for preventing moisture permeation on the back surface of the first base film layer 2 is performed, thereby completing the formation of the first layer.

On the other hand, apart from the formation of the sieve 1 layer, the step of forming the alumina (Al ₂ O ₃ ) deposition layer 5 by depositing alumina (Al ₂ O ₃ ) on the upper surface of the second base film (second step) Proceed.

Then, the step (third step) of adhering the alumina-deposited second base film and the barrier layer 3 constituting the first layer through the UV-curable adhesive is performed.

Then, a step (fourth step) of forming the EVA adhesion layer 7 on the back of the second base film is in progress.

Hereinafter, the physical features required for the individual layers of the solar cell backsheet B of the present invention constructed and manufactured as described above, a suitable constituent material, and a component embodiment will be described.

Although the present invention will be described in more detail with reference to the following examples, the following examples are only for illustrating the present invention, and the protection scope of the present invention is not limited to the following examples.

[ Example  One]

One. Outermost layer

First, the functional coating layer 1 constituting the outermost layer is a part in contact with the external environment when the back sheet B is attached to a solar cell module, and should have excellent physical properties such as hardness, durability, and weather resistance. .

Accordingly, the functional coating layer 1 includes (A), (B) and (C) in Table 1 below, a functional organic-inorganic filler (D in Table 1 below), and a physical property improving additive (Table 1 below). (E), (F)), and a solvent (G) of Table 1 below, and the specific components of the components forming the functional coating layer 1, and their minimum and maximum contents are shown in a table. It is shown in [Table 1] below.

division Example Content (% by weight) min content (% by weight) max content (wt%) (A) acrylate oligomer 48 20 77.4 (B) acrylate monomer 7 5 10 (C) photoinitiator 2.5 0.5 5 (D) functional organic-inorganic filler 15.5 1.5 20 (E) Leveling agent One 0.5 3 (F) dispersant 0.5 0.1 1.5 (G) Solvent 25.5 20 75 100

The kind and physical properties of the material constituting each component disclosed in Table 1 above are as follows.

(A) acrylate oligomer

Urethane acrylate, Epoxy acrylate, Polyester acrylate, Silicone acrylate, Melamine acrylate, Polyether acrylate, etc. 4 and 6 functional aromatic and aliphatic urethane acrylates or 4 to 6 functional aliphatic polyester acrylates are used.

(B) acrylate monomer

Mainly used as a 2-3 functional monomer to reduce the viscosity of the oligomer and improve the coating properties. In addition, pentaerythritol tetraacrylate (PETTA) is added as a functional monomer to improve the physical properties of the coating layer. The monomer has a feature of increasing the wear resistance and hardenability of the coating layer, independently of the additive function.

(C) Photo-initiator: A substance added to a UV resin to absorb ultraviolet energy to start a polymerization reaction. A benzene, a benzene isomer compound, a benzyl ketal compound, and an α-hydroxy alkylphenone compound. , α-aminoalkylphenone derivative compounds, halogen compounds, benzophenone derivative compounds and the like can be used.

(D) Functional fillers: These are materials for improving physical properties such as water repellency, abrasion resistance, etc., and the characteristics of each material are as shown in items a) to d) below.

end). PTFE powder (Polytetrafluoroethylene powder)

Product: CERAFLOUR 980 (BYK), TEFLONPTFE powder (Du Pont), Algo flonF series (Solvay Solexis) / Characteristics: scratch resistance, abrasion resistance, weather resistance

I). Synthetic wax manufactured by Fischer tropsch process

Product: CERAFAK 116 (BYK), VESTOWAXSH 105 (Evonik Degussa), Sasolwax SP30 (EPChem) / Properties: Water repellent, Pollution resistance

All). PTFE modified polyethylene powder or wax

Product: LANCO ™ TF 1725 series (Lubrozol), CERAFLOUR 998 (BYK), Ceridust3920 (Clariant) / Characteristics: scratch resistance, water repellency

la). Carnauba wax

Product: CERAFLOUR 988 (BYK), LANCO ™ GLIDD 4838 (Lubrozol), / Characteristics: Scratch resistance Slip resistance

(E) Leveling agent: An additive added to improve the adhesion of the smooth surface and the substrate of the coating layer. Products and properties of each material are as shown in the following items a) to d).

end). Polyether modified polydimethylsiloxane

· Characteristic: It greatly reduces the surface tension to increase the material wetting, and gives slip and leveling at the same time.

Product: BYK-302 (BYK), BaysilonePaint Additive 3466 (Borchers)

I). Polyester modified polydimethylsiloxane

· Characteristic: Improves thermal stability of coating layer and improves leveling.

Product: BYK-310 (BYK), BYK-377 (BYK)

All). Polymeric fluorosurfactant

· Characteristics: It has excellent leveling and material wettability.

Product: BYK-340 (BYK), FC-4430 (3M), ZonylFSN-100 (DU Pont)

The leveling agent is used alone or in combination of the above three, in particular, the polydimethyl siloxane-based leveling agent is combined with the acrylate of the UV curable resin on the surface to effectively improve the slip properties and water resistance of the surface properties of the coating layer and other surfaces Improve the stability of physical properties.

(F) Dispersant: A substance added for the even dispersion of functional fillers, the actual products and properties of which are indicated in items a) and b) below.

end). A high molecular weight block copolymer with groups of pigments affinity

Product: BYK-168 (BYK company)

I). Modified polyether with groups of high pigments affinity

Product: TEGODispers 656 (Evonik Degussa)

(G) Solvent: A substance which is added to exhibit a suitable viscosity and coatability for coating.

Solvents may include MEK (Methyl ethyl keton), Toluene, EA (Ethyl acetate), Cyclohexanone, BA (Buthyl acetate), and the like.

2. Middle layer

The intermediate layer disposed between the outermost layer and the innermost layer is composed of a barrier layer 3 for preventing moisture permeation, an adhesive layer 4 having light resistance due to the UV blocking effect, and an alumina deposition layer 5 having electrical insulation.

As can be seen from FIG. 2, the intermediate layer comprises a barrier layer 3 for preventing moisture permeation, an adhesive layer 4 having light resistance due to the UV blocking effect, and an alumina deposition layer 5 having electrical insulation. These layers must express stable functions in moisture resistance, heat resistance and weather resistance.

Accordingly, the intermediate layer serving as the functional coating layer includes UV curable resins ((A), (B) and (C) in Table 2 below) and functional organic and inorganic fillers ((D) and (E) in Table 2 below), It is composed of physical property improving additives ((F), (G) of Table 2 below) and solvent ((H) of Table 2 below), and the specific components and their minimum and maximum contents are shown in the table below. 2].

division Example Content (% by weight) min content (% by weight) max content (wt%) (A) acrylate oligomer 52 20 77.4 (B) acrylate monomer 7.5 5 10 (C) photoinitiator 2.5 0.5 5 (D) functional organic-inorganic filler 9.2 1.5 20 (E) UV absorbers 3 0.1 10 (F) Leveling agent One 0.5 3 (G) dispersant 0.5 0.1 1.5 (H) Solvent 24.3 20 75 100

The types and physical properties of the materials constituting the components shown in Table 2 above are as follows.

UV-curable resins ((A), (B) and (C) in Table 2 above), physical property additives ((F) and (G) in Table 2 above), and solvents ((H) in Table 2 above) The type of material and its physical properties are the same as those of the outermost layer, so it is omitted in order to avoid duplication of description, and only the functional organic-inorganic filler (D) and the ultraviolet absorber (E) will be described.

(D) Functional organic-inorganic filler: As a filler added to prevent moisture permeation, in the past, inorganic oxides were vacuum deposited, but according to the present invention, the method of coating the moisture-permeable filler into the coating to reduce the cost significantly. We can plan.

Generally, hydrophobic materials include silica, talc, mica, carbon, and the like, and surface-modified silica is used in the present embodiment. The features and product examples are as follows.

Features: Silica modified to show hydrophobicity by Sol-gel method

Products: Aerosil R 972 Phama (Evonik Degussa), Perform-O-Sil 668 (PPI) and HDK H17 (Wacker) used alone or in combination

(E) UV absorber: A substance that absorbs UV rays to prevent internal penetration and prevents physical changes such as discoloration and hardening caused by UV rays. UV absorbers include benzophenone-based (ultraviolet absorption range 300-380 nm), There are benzotriazole type (absorption range 300 ~ 385nm), salicylic acid type (absorption range 260 ~ 340nm), acrylonitrile type (absorption range 290 ~ 400nm), organic nickel compound and mono benzoic acid type.

Products: Tinuvin292 (Basf), Pamsorb-326 (Polymate), Hisorb-326 (LG)

2-1: Adhesive layer

The adhesive layer 4 constituting the intermediate layer serves to attach and harden the first layer and the second layer. An ultraviolet curable adhesive, a thermosetting oily adhesive, a thermosetting aqueous adhesive, and a hotmelt adhesive can be used. In the example, an ultraviolet (UV) curable adhesive is used.

The UV-curable adhesive is a product that the photoreaction initiator in the adhesive starts to react when irradiated with ultraviolet rays through the ultraviolet curing equipment and cures within seconds, and can be easily and simply applied to various materials, and thus can be firmly produced. Since it is easy to apply and hardens quickly without any congestion, it contributes greatly to productivity improvement, such as the configuration of the product production line is easy when the production line is applied.

Therefore, it is suitable for most applications such as bonding, sealing, coating, encapsulation, and tacking required in various fields.

In terms of its properties, it is a one-component, solvent-free type, cured within seconds, and is optimal for mass production lines.It has excellent reliability such as moisture resistance and environmental resistance, beautiful appearance, excellent external and surface curing speed. It is suitable for the present invention because it has excellent adhesion to both the functional coating layer 1 and the alumina (Al ₂ O ₃ ) deposition layer 5.

Adhesive products for practical applications include LOCTITE3103 ™ (Loctite), Scotch-weld ™ UV Adhesives UV011 (3M) and Tru-Bond ™ PB 3500 UV Adhesive (ITW).

3. Outermost layer

The outermost layer is composed of a second base film layer 6 and an EVA adhesion layer 7, and the second base film layer is a polyethylene terephthalate (PET) film, a polycarbonate (PC) film, a polyimide (PI) film, or a PEN ( Polyethylenenaphthalate) film, PET film is mainly used because the physical properties of transparency, heat resistance, and moisture resistance is relatively excellent compared to other films, preferably heat resistance low having a high transparency of 90% or more transmittance Oligomeric PET film is used.

On the other hand, the back sheet (B) is finally attached to the EVA layer of the solar cell module, but when attached to the untreated PET film, the adhesion is low and the cracks in the adhesion layer with time This adversely affects the life of the solar cell module. Because of this, the layers must be subjected to a separate pretreatment process to maintain a firm attachment.

In other words, mainly LLDPE (Linear low-density polyethylene), EVA-based hotmelt adhesive or TPU (Thermal polyurethane) is coated by T-die coating method, which is a kind of extrusion coating method, preferably LLDPE with low cost and good adhesion properties is used.

It will be apparent to those skilled in the art that the present invention can be embodied in other specific forms without departing from the spirit or scope of the invention as defined in the appended claims. It is obvious to them.

Therefore, it is to be understood by those skilled in the art that the above-described embodiments are to be considered as illustrative and not restrictive, and therefore, the present invention is not limited to the above description but may be changed within the scope of the appended claims and their equivalents. Will be called.

The present invention is to implement the physical properties such as heat, moisture, mechanical, etc. in two layers with the organic-inorganic hybrid technology (technology that implements the processing and mechanical and chemical properties at the same time by using a combination of organic and inorganic materials) in the solar cell back sheet, Simplify the manufacturing process of the solar cell backsheet and reduce the cost, thereby reducing the manufacturing cost and improving the backsheet supply situation that cannot meet the demand for solar cell module manufacturing. It is a very likely invention.

1: functional coating layer 2: first base film layer
3: moisture barrier layer 4: adhesive layer
5: alumina deposition layer 6: second base film layer
7: EVA adhesion layer

Claims (6)

First base film layer made of heat-resistant low oligomeric PET having a light transmittance of 90% or more,
A functional coating layer formed on the upper surface of the first base film layer to form an outermost layer of the backsheet together with the first base film layer, and to satisfy hardness, durability, and weather resistance, which are physical properties required as the outermost layer, and
A first layer having a barrier layer formed on a rear surface of the first base film layer to prevent moisture permeation;
Second base film layer made of heat-resistant low oligomeric PET having a light transmittance of 90% or more,
The innermost layer of the backsheet is formed together with the second base film layer, and an alumina is formed on the upper surface of the second base film layer so as to satisfy heat resistance, cold resistance, fracture resistance, and electrical insulation, which are physical properties required as the innermost layer. A deposition layer, and
A second layer having an EVA adhesion layer formed on a rear surface of the second base film layer to be attached to an EVA layer of a solar cell module;
And an adhesive layer interposed between the first layer and the second layer to attach the first layer and the second layer to block ultraviolet rays.
The functional coating layer is 20 to 72.4% by weight of acrylate oligomer, 5 to 10% by weight of acrylate monomer, 0.5 to 5% by weight of photoinitiator, 1.5 to 20% by weight of functional organic-inorganic filler, 0.5 to 3% by weight of leveling agent, and dispersant 0.1 ~ 1.5% by weight, a solar cell back sheet comprising a 20 to 72.4% by weight solvent. delete delete The method of claim 1,
The EVA adhesion layer is a solar cell back sheet, characterized in that made of LLDPE (inear low-density polyethylene). The method of claim 1,
The adhesive layer is a solar cell back sheet, characterized in that made of an ultraviolet curable adhesive. A first process of forming a functional coating layer on an upper surface of the first base film layer, and
A first step of forming a first layer by performing a second process of coating a barrier layer for preventing moisture permeation on the back surface of the first base film layer;
A second step of forming an alumina (Al ₂ O ₃ ) deposition layer by depositing alumina (Al ₂ O ₃ ) on the upper surface of the second base film;
A third step of adhering a second base film on which alumina is deposited and a barrier layer constituting the first layer through a UV curable adhesive;
Method for manufacturing a back sheet for a solar cell of claim 1 characterized in that it comprises a; the fourth step of forming an EVA adhesion layer on the back of the second base film.

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