JPH08242010A - Solar cell module - Google Patents

Abstract

PURPOSE: To obtain a solar cell module in which a transparent plastic film provided with a moisture-proof layer on light incident side is used as a covering material. CONSTITUTION: A solar cell module is produced by forming a thin-film layer made of silicon oxide and metal fluoride and/or magnesium oxide through a vacuum thin-film formation technology on one surface or both surfaces of a plastic film (excluding fluorine resin based film) that is used to cover the light incident surface of a solar cell including photovolatic elements that are mainly composed of a conductive substrate, rear electrode, semiconductor layer, transparent electrode layer, and collecting electrode.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solar cell module which uses a transparent plastic film (excluding a fluororesin film) having a moisture-proof layer on the light incident surface side as a covering material.

[0002]

2. Description of the Related Art In recent years, solar cells have attracted attention as a clean energy source free from environmental pollution due to increasing awareness of environmental problems, and earnest research and practical application have been made from the viewpoint of utilizing solar energy as a useful energy resource. .
There are various forms of solar cells, and typical ones are crystalline silicon solar cells, polycrystalline silicon solar cells,
Amorphous silicon solar cells, copper indium selenide solar cells, compound semiconductor solar cells, etc. are known. Among them, the thin film crystal solar cell, the amorphous silicon solar cell, and the compound semiconductor solar cell are relatively low in cost and can have a large area, and therefore, research and development are actively conducted in various fields. In addition, among these solar cells, a thin film solar cell typifying an amorphous silicon solar cell in which silicon is deposited on a conductive metal substrate and a transparent conductive layer is further formed on the conductive metal substrate is lightweight, and has impact resistance and Due to its high flexibility, it is promising as a future module form for solar cells.

However, unlike the case of depositing silicon on a glass substrate in the above-mentioned thin film solar cell, it is necessary to protect the solar cell by covering the light incident side surface with a transparent coating material. As this surface coating material, a transparent fluoropolymer thin film such as a fluororesin film or a fluororesin paint having high weather resistance, or another plastic film having high weather resistance is used. The reason why the plastic having high weather resistance is used is that it is possible to suppress a decrease in conversion efficiency of the solar cell module caused by a decrease in light transmittance due to deterioration. Japanese Patent Laid-Open No. 5-283727 discloses a solar cell module in which at least one surface of a fluororesin film is coated with a transparent inorganic compound in order to prevent a decrease in output of the solar cell due to the influence of moisture, thereby improving moisture resistance. Is proposed. However, the fluorine film used here is extremely expensive, which is one of the reasons that the cost of the solar cell does not decrease. In addition, among the inorganic compounds to be coated, for example, the inorganic compounds produced when silicon oxide is coated by the sputtering method. The thin film layer has a dark brown color, which cuts off sunlight and has a drawback that the conversion efficiency of the solar cell module is reduced due to the decrease in light transmittance.

[0004]

SUMMARY OF THE INVENTION The object of the present invention is to solve the above-mentioned problems, namely, to improve the moisture-proof property at the same time without lowering the transparency and the conversion efficiency, and to obtain a material other than a very expensive fluororesin film. It is intended to provide a solar cell module using a weather resistant plastic material as a covering material.

[0005]

The present invention provides a conductive substrate,
On one or both sides of a plastic film (excluding fluororesin film) that covers the light incident surface of a photovoltaic cell including a photovoltaic element mainly composed of a back electrode, a semiconductor layer, a transparent electrode layer, and a collector electrode This can be achieved by a solar cell module in which a thin film layer made of silicon oxide and metal fluoride and / or magnesium oxide is formed by a vacuum thin film forming technique. The present invention will be described more specifically. The solar cell module is mainly composed of a back reinforcing plate / a photovoltaic film arranged in parallel by an adhesive / a plastic film laminated with thin film layers / a plastic film. In addition, a solar cell module whose surface is coated with a plastic film having a thin film layer laminated on the side opposite to the light incident side, or a plastic film having a thin film layer laminated on the light incident side may be used. Of course, it is also possible to coat the solar cell with a plastic film having thin film layers laminated on both sides.

By laminating a thin film layer on one side or both sides of the surface of the plastic film, it is possible to suppress the intrusion of moisture from the outside and reduce the decrease in the output of the solar cell. Therefore, the output of the solar cell can be stably obtained even by light irradiation in a high humidity atmosphere. As the photovoltaic element used in the present invention, an element manufactured by a known method from a known amorphous silicon or a compound semiconductor is used. A metal plate such as a stainless steel plate or an aluminum plate is mainly used as the back reinforcing plate, but a weather-resistant plastic material having a thin film layer like the light incident surface can also be used.

The adhesive layer is a vinyl acetate ethylene copolymer (E
VA) resin, ionomer resin, ethylene ethyl acrylate copolymer (EEA) resin, ethylene methacrylic acid random copolymer (EMAA) resin, ethylene acrylic acid copolymer (EAA) resin, ethylene methyl methacrylate copolymer ( EMMA) resin, ethylene methyl acrylate copolymer (EMA) resin, and other adhesive polyolefin resin can be used. E in terms of weather resistance and transparency
VA resin and ionomer resin are preferable. As the weather resistant plastic film, there are films of polyethylene terephthalate, polycarbonate, polyethylene-2,6-naphthalene dicarboxylate, polysulfone, polyacrylate, polyether sulfone, polyarylate, polyetherimide and polyallyl sulfone. Can be used. Also mixed with those films and /
The applied UV absorber is not particularly limited, but salicylic acid-based UV absorber, benzophenone-based UV absorber, benzotriazole-based UV absorber, cyanoacrylate-based UV absorber, UV stabilizer, hindered amine-based light stabilizer However, the present invention is not limited to this.

As a method for obtaining the thin film layer used in the present invention, a vacuum thin film forming technique is used on the surface of a plastic film having weather resistance, and it is composed of silicon oxide, metal fluoride and / or magnesium oxide. Laminate thin film layers. Examples of the silicon oxide forming the thin film layer include SiOx (x is greater than 1.0 and less than 2.0).
Si ₂ O ₃ and Si ₃ O ₄ are included in this. In SiOx, x is preferably in the range of more than 1.0 and less than 2.0, and particularly preferably in the range of more than 1.8 and less than 2.0. Examples of metal fluorides that form the thin film layer include beryllium fluoride, magnesium fluoride, calcium fluoride, strontium fluoride, barium fluoride, aluminum fluoride, lithium fluoride, sodium fluoride, potassium fluoride, fluorine. Rubidium iodide, cesium fluoride, francium fluoride, etc. are mentioned. In particular, alkaline earth metal fluorides are excellent, and magnesium fluoride and calcium fluoride are particularly excellent.

Examples of the magnesium oxide constituting the thin film layer include magnesium oxide, forsterite, stearite, a co-oxide of magnesium oxide and silicon dioxide, and a complex compound of magnesium oxide and metal fluoride. Can be mentioned. When the metal fluoride is an alkaline earth metal fluoride, SiOx (x is 1.0
Larger than less than 2.0) and a fluoride of an alkaline earth metal, or SiOx (x is larger than 1.0,
(Less than 2.0), a combination of an alkaline earth metal fluoride and magnesium oxide. That is, the thin film layer is SiOx.
(X is greater than 1.0 and less than 2.0) -Alkaline earth metal fluoride compound, or SiOx (x is greater than 1.0 and less than 2.0) -Alkaline earth metal fluoride- It consists of a compound of magnesium oxide.

SiOx (x is greater than 1.0 and 2.0
The metal thin film layer is excellent in both moisture resistance and light transmittance, but is particularly excellent in light transmittance, and SiOx (x is larger than 1.0 and less than 2.0) -metal fluoride-oxidized. The thin film layer of magnesium is also excellent in moisture resistance and light transmission, but particularly excellent in moisture resistance. SiO that constitutes the thin film layer
The composition ratio of x (x is greater than 1.0 and less than 2.0) and the metal fluoride is 98 to 80 mol% and 2 to 20, respectively.
The ranges of mol% are desirable, and the ranges of 95 to 90 mol% and 5 to 10 mol% are particularly desirable. When it contains magnesium oxide, SiOx (x is 1.0
It is preferable that the composition ratios of the metal fluoride and the magnesium oxide are 97.5 to 80 mol%: 2 to 19.5 mol%: 0.5 to 18 mol%, respectively. , Especially 93 to 88 mol%: 5 to 10 mol%: 2
The range of -17 mol% is desirable.

The raw material for the thin film layer laminated on the plastic film may be an inorganic compound such as a metal oxide, a metal fluoride, a metal or an organic metal compound, or an organic compound alone or in a mixture. In particular, a mixture of silicon oxide and metal fluoride or a mixture of silicon oxide, metal fluoride and a co-oxide of silicon dioxide and magnesium oxide is used as a raw material, and a thin film layer is directly formed on the plastic film by vacuum deposition or the like. A method of forming is desirable. The composition ratio of the raw materials is, in the case of silicon oxide and metal fluoride, silicon oxide: metal fluoride = 98 to 70 mol%: 2 to 30 mol%.
The range of is desirable. Particularly preferably, silicon oxide: metal fluoride = 95 to 85 mol%: 5 to 15 mol%. In the case of silicon oxide, metal fluoride and a mixture of silicon dioxide and magnesium oxide co-oxide,
Silicon oxide: Metal fluoride: Silicon dioxide and magnesium oxide co-oxide = 97.5-70 mol%: 2-2
9.5 mol%: The range of 0.5 to 28 mol% is desirable.
Particularly preferably, silicon oxide: metal fluoride: cooxide of silicon dioxide and magnesium oxide = 95 to 90 mol%: 4.5 to 9.5 mol%: 0.5 to 5.5 mol%. It is a range.

Examples of the silicon oxide used as a raw material include a mixture of silicon and silicon dioxide, a simple substance of silicon monoxide, and a mixture of silicon, silicon dioxide and silicon monoxide. When a silicon oxide is used as a mixture of silicon (Si) and silicon dioxide (SiO ₂ ), the composition ratio at that time is basically preferably equimolar, but Si: Si
O ₂ = 40-60 mol%: It should be in the range of 60-40 mol%. The silicon oxide used as a raw material is Si or S.
In the case of a mixture of iO and SiO ₂ , Si: SiO ₂
Should be approximately equimolar, and (Si + SiO ₂ ): Si
The ratio of O is not particularly limited.

A vacuum thin film forming technique for forming a thin film layer on a plastic film may be either a continuous winding system or a single-wafer system, and the forming method is not particularly limited, and vacuum deposition, ion plating, A PVD method such as sputtering or a CVD method such as plasma CVD or microwave CVD can be used. Further, the heating method for vacuum vapor deposition is not particularly limited as long as it does not cause vapor deposition droplets called splash during vapor deposition and is small enough to be removed without trouble, and conventional methods such as high frequency induction heating, resistance heating, and electron beam heating are used. A known heating method can be used. When a large amount of this vapor deposition droplet is generated, the droplet remains as a foreign substance on the vapor deposition film,
Many problems occur in the emulsion coating process, the exposure process, and the development process, which are the subsequent processes. A general crucible system may be used as an evaporation source for vacuum vapor deposition, but substances having different sublimation points and melting points can always be vapor-deposited uniformly in JP-A-1-252768.
Also, the method of continuously supplying and discharging the evaporation raw material as shown in JP-A-2-277774 is desirable.

The degree of vacuum when vacuum-depositing the mixture of silicon oxide and metal fluoride or the mixture of silicon oxide, metal fluoride and co-oxide of silicon dioxide and magnesium oxide is 1 5 × from 10 ⁻⁴ torr
It is preferably within the range of 10 ⁻³ torr. For high vacuum,
Although the composition of the raw material can be directly reflected on the composition of the thin film layer, on the contrary, when the degree of vacuum is low, the composition of the thin film layer has excess oxygen atoms (high degree of oxidation) as compared with the composition of the raw material.
This is considered to be a reaction between the vapor deposition particles and oxygen atoms during vapor deposition. In terms of film structure, it is presumed that a high-density thin film layer can be obtained when the degree of vacuum is high, while a low-density film is obtained when the degree of vacuum is low. By using the degree of vacuum within the above range and using the raw material having the above composition, a desired composition ratio for the thin film layer can be obtained.

As a method of laminating thin film layers other than the above, a method of vacuum vapor deposition while oxidizing or fluorinating a metal or a compound containing a metal such as an organometallic compound, or a metal fluoride as a vapor deposition layer on a plastic film is used. There is a method of forming the film and then subjecting the vapor-deposited layer to an oxidation treatment in a subsequent step. The method of oxidation treatment is not particularly limited as long as it is a method of performing treatment within the usable temperature range of the plastic film, and examples thereof include an oxygen gas introduction method during vapor deposition, a discharge treatment method, an oxygen plasma method, and a thermal oxidation method. The thickness of the thin film layer is selected according to the plastic film used, but in the present invention, it is preferably 50 to 2500 angstroms per side. Particularly, 300 to 1200 angstrom is desirable. Further, the laminated thin film layers may be double laminated layers or multiple laminated layers as long as the required function of the finally obtained layer is obtained. That is, the stacking may be performed twice or more, and different kinds of metal fluorides may be stacked at that time.

As an example of the method for producing the solar cell module of the present invention, a photovoltaic element sandwiched between adhesive sheets is placed on a back reinforcing plate, covered with a plastic film, and a pressure of about 1 kg / cm ² is applied under reduced pressure. Then, a method of heating and laminating for a predetermined time to manufacture is adopted. As the adhesive layer of the plastic film in which the thin film layers of the present invention are laminated, a transparent resin such as vinyl acetate-ethylene copolymer, polyvinyl butyral, silicone resin, epoxy resin, fluorinated polyimide resin, acrylic resin, polyester resin is mainly used. Use an adhesive as a component. It is desirable that the adhesive contains a cross-linking agent and an ultraviolet absorber in order to suppress photodegradation of the adhesive.

Further, in order to reduce the decrease in photoelectric conversion efficiency of the solar cell module, the light transmittance of the adhesive layer is preferably 80% or more in the wavelength range of 400 nm or more. In addition, the refractive index of the adhesive is preferably in the range of 1.4 to 2.0 in order to reduce the loss due to reflection of incident light. The photovoltaic element used in the solar cell module of the present invention is, for example, composed of a conductive substrate / back surface electrode / semiconductor layer as a photoelectric conversion member / transparent electrode layer / collecting electrode. The back electrode layer can also serve as a conductive substrate. As the conductive substrate, for example, stainless steel, aluminum, copper, titanium, carbon sheet, galvanized steel plate, etc., and resin film or ceramic such as polyimide, polyester, poly (ethylene naphthalate), epoxy having a conductive layer are formed. Can be mentioned.

A compound semiconductor such as amorphous silicon, crystalline silicon, or copper indium selenide is preferably used as the semiconductor layer, and the semiconductor layer is composed of p
In-junction, pn-junction, and Schottky junction are used. When amorphous silicon is used, it is formed by plasma CVD using, for example, silane gas, and when it is polycrystalline silicon, it is formed by sheeting of molten silicon or heat treatment of amorphous silicon. CuInSe
_In the case of ₂ / CdS, it is formed by a method such as electron beam vapor deposition, resistance heating vapor deposition, high frequency induction heating vapor deposition or sputtering, ion plating, and electrodeposition (deposition by electrolytic decomposition of electrolytic solution). Further, the resistance heating method of the method of continuously supplying and discharging the evaporation raw material as shown in JP-A-1-252768 and JP-A-2-277774 may be used.

The semiconductor layer has a structure sandwiched at least by the back electrode layer and the transparent conductive layer. A metal layer, a metal oxide layer, or a composite layer of a metal layer and a metal oxide layer is used for the back electrode. As the material of the metal layer, for example, Ti, Cr, Mo, W, Al, Ag, N
i, Cu, Au, etc. are used, and Z is used as the metal oxide layer.
nO, TiO ₂ , SnO _2, etc. are adopted. As the method for forming the metal layer and the metal oxide layer, for example, electron beam vapor deposition, resistance heating vapor deposition, high frequency induction heating vapor deposition, sputtering, ion plating, electrodeposition (deposition by electrolysis of electrolytic solution), or the like is used. To do. Also, Japanese Patent Laid-Open No. 1-
252768 and JP-A-2-277774 may employ a resistance heating method of continuously supplying and discharging the evaporation raw material.

The material used for the transparent electrode layer is, for example, In ₂ O ₃ , SnO ₂ , In ₂ O ₂ —SnO ₂ (ITO), Z.
There are nO, TiO ₂ , Cd ₂ SnO ₄ , crystalline semiconductor layers doped with high-concentration impurities, and the like.
For example, it is formed by a method such as electron beam evaporation, resistance heating evaporation, high frequency induction heating evaporation, sputtering, ion plating, and electrodeposition (deposition by electrolysis of an electrolytic solution). Further, JP-A-1-252768 and JP-A-2-277
A resistance heating method of continuously supplying and discharging the evaporation material shown by 774 may be used. It is formed by methods such as electron beam evaporation, resistance heating evaporation, high frequency induction heating evaporation and sputtering, ion plating, spraying, CVD, and impurity diffusion. Also, Japanese Patent Laid-Open No. 1-252768
Alternatively, the resistance heating method shown in JP-A-2-277774, which continuously supplies and discharges the evaporation source, may be used.

A photovoltaic element is manufactured by first forming a back electrode layer, a semiconductor layer, and a transparent electrode layer on a conductive substrate, and then forming a collector electrode. Examples of the material for the current collecting grid electrode include Ti, Cr, Mo, W, Al, Ag, N
A metal such as i, Cu, Sn, Au, or Pd, and a conductive paste such as a silver paste are used. The grid electrode can be formed by, for example, sputtering using a mask pattern, ion plating, resistance heating, high frequency induction heating, a CVD deposition method, or a method in which a metal layer is deposited on the entire surface and then etched and patterned, or photo CVD. There are a method of directly forming a grid electrode pattern, a method of forming by plating after forming a mask of a negative pattern of the grid electrode pattern, a method of forming a conductive paste by printing, and the like. When silver is not used for the grid electrode material, silver paste is used as a conductive adhesive that bonds the grid electrode and the current collecting bus bar.

The conductive paste is usually, for example, silver, gold,
A fine powder metal such as copper, nickel or carbon dispersed in a binder polymer is used. Examples of the binder polymer include resins such as polyester, epoxy, acrylic, alkyd, polyvinyl acetate, rubber, urethane and phenol. As the backing material of the solar cell module of the present invention, if necessary, for example, various insulating resins, ceramics, glass, an insulating laminated metal substrate aluminum laminate film, silicon oxide, and metal fluorides and / or magnesium oxides. Polyethylene terephthalate, polycarbonate, polyethylene-2,6-naphthalene dicarboxylate, polysulfone, polyacrylate, polyether sulfone, polyarylate, polyetherimide, polyallyl sulfone, fluororesin film Are used.

[0023]

[Effects of the Invention] Although the water vapor permeability of the plastic film provided with the vapor-deposited thin film layer according to the present invention was reduced to 1/10, no deterioration of the light transmittance was observed and the light incident on the solar cell was not observed. It was an ideal material for coating surfaces.

[0024]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited thereto. (Light transmittance measuring method): The light transmittance at 400 nm was measured using a spectrophotometer (U-best30, manufactured by JASCO Corporation) with air as a reference. (Measurement method for moisture resistance): PERMATRAN manufactured by Modern Controls Inc. of the United States according to ASTM F 1249
The water vapor transmission rate was measured using -W-TWIN. The smaller this value, the better the moisture resistance. (Solar cell output test): The prepared solar cell module was irradiated with light of 100 mW / cm 2, and the electromotive force output was measured. (Exposure test): Under the conditions of low temperature -40 ° C to high temperature 85 ° C and relative humidity 85% while irradiating the surface-coated solar cell module with light of AM1.5 100 mW / cm ² using an environmental tester. 10 cycles of temperature and humidity cycle
AM1.5 100mW / cm for photovoltaic device after test
The light irradiation of 2 was performed and the electromotive force output was measured. Example 1 Polyethylene terephthalate (manufactured by Tetoron HB Teijin Limited) having a thickness of 25 μm and kneaded with an ultraviolet absorber was used in JP-A-1.
Using a resistance heating type vacuum vapor deposition machine of the type which continuously supplies and discharges the evaporation raw material shown in -252768, a mixture of 90 mol% to 10 mol% of silicon monoxide and magnesium fluoride is vapor-deposited, and 600 angstrom Thin films were laminated.

This film has light transmittance and moisture resistance.
It was measured. Table 1 shows the results. Next, amorphous silicon (a
-Si) photovoltaic element was prepared. Washed 0.15
Back side of thick stainless steel substrate using sputtering method
As an electrode, Al film thickness 500 nm, ZnO film thickness 500 n
m were sequentially formed. Next, by the plasma CVD method, Si
H_FourAnd PH₃And H₂From n-type a-Si layer to SiH_FourAnd H ₂
From i-type a-Si layer to SiH_FourAnd BF₃And H₂To p-type
A microcrystalline μc-Si layer is formed, and the thickness of the n layer is 15 nm / i layer
Film thickness 400 nm / p layer film thickness 10 nm / n layer film thickness 10 nm
/ Half of laminated structure with i-layer thickness 80 nm / p-layer thickness 10 nm
After forming the conductor layer, an ITO target as a transparent electrode
Was sputtered to form an ITO film having a thickness of 700 nm.

Then, a silver paste (Lexbond T-700 manufactured by Toyo Ink Mfg. Co., Ltd.) was printed in a grid pattern by a screen printing machine and then heat-treated at 125 ° C. to form a collector electrode. A power device was created. A predetermined size was cut out from the polyethylene terephthalate kneaded with the ultraviolet absorber, in which silicon monoxide and magnesium fluoride were laminated, and used as a coating material for a solar cell module. As a transparent adhesive, a sheet-shaped EVA formed by adding a crosslinking agent and an ultraviolet absorber was used. An insulating treated zinc steel plate was used as the back material.

The photovoltaic elements produced by the above method were connected in series and in parallel so as to obtain a predetermined output, and then the thin film layer of the polyethylene terephthalate film mixed with the ultraviolet absorber was arranged so as to contact the adhesive EVA 102. hand,
Ultraviolet absorbent kneaded polyethylene terephthalate film / EVA / photovoltaic element / EVA / insulating treated zinc steel plate laminated in this order from the light incident layer, then put in a vacuum laminator and evacuated to about 1 Torr The surface coating of the solar cell was performed by heating at 140 ° C. for 30 minutes under the atmospheric pressure. However, the output terminal of the solar cell was taken out by making a hole for the output terminal in the zinc steel plate of the back material in advance.

A solar cell output test was carried out on the obtained surface-coated solar cell module. Next, an exposure test was conducted. The results are shown in Table 1. Example 2 Polyethylene naphthalate (manufactured by Teonex Teijin Limited) having a thickness of 12 μm and kneaded with an ultraviolet absorber was added to JP-A 1-2.
Japanese Laid-Open Patent Publication No. 52768 discloses a vacuum evaporation machine of a resistance heating system that continuously supplies and discharges evaporation materials, and uses silicon, silicon dioxide, calcium fluoride, and forsterite (mixing ratio: 45 mol% / 45 mol). % / 8 mol% / 2 mol% mixture was evaporated to deposit a 600 angstrom thin film.

The light transmittance and moisture resistance of this film were measured. The results are shown in Table 1. The method of modularizing the solar cell and the surface coating were the same as in Example 1.
A solar cell output test was performed on the obtained surface-coated solar cell module. Next, an exposure test was conducted. The results are shown in Table 1. Comparative Example 1 The mixture of silicon monoxide and magnesium fluoride of Example 1 was not vacuum-deposited, and the same procedure was followed as in Example 1. The results are shown in Table 1. Comparative Example 2 Using the polyethylene terephthalate kneaded with the ultraviolet absorbent of Example 1, a mixture of silicon monoxide and magnesium fluoride was vacuum-deposited in place of vacuum vapor deposition.
An angstrom thin film was sputtered. The rest was the same as in Example 1. The results are shown in Table 1.

Comparative Example 3 An ETFE fluororesin film (made by Daikin) which is a fluororesin film was used in place of the polyethylene terephthalate kneaded with the ultraviolet absorbent of Example 1, and a mixture of silicon monoxide and magnesium fluoride was vacuum-deposited. instead of,
Only silicon monoxide was sputtered into a 600 angstrom thin film. The rest was the same as in Example 1. The results are shown in Table 1.

[0031]

[Table 1]

Claims (5)

[Claims] 1. A plastic film (a fluororesin-based resin film) covering a light incident surface of a solar cell including a photovoltaic element mainly composed of a conductive substrate, a back electrode, a semiconductor layer, a transparent electrode layer and a current collecting electrode. A solar cell module having a thin film layer formed of silicon oxide and metal fluoride and / or magnesium oxide formed on one or both sides (excluding the film) by a vacuum thin film forming technique. 2. The solar cell module according to claim 1, wherein the metal fluoride constituting the thin film layer is one or more selected from magnesium fluoride and calcium fluoride. 3. A magnesium oxide constituting a thin film layer,
The solar cell module according to claim 1, which is one or more selected from the group consisting of magnesium oxide, a co-oxide of magnesium oxide and silicon dioxide, and a complex compound of magnesium oxide and metal fluoride. 4. A plastic film constituting a solar cell module is made of poly (ethylene terephthalate), polycarbonate, poly (ethylene-2,6-naphthalene dicarboxylate), polysulfone, polyacrylate, polyether sulfone, polyarylate, polyetherimide, polyallyl. The solar cell module according to claim 1, which is a sulfone. 5. The solar cell module according to claim 1, wherein the plastic film forming the solar cell module is mixed and / or coated with an ultraviolet absorber.