JP3293391B2 - Solar cell module - Google Patents

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 using a transparent plastic film (excluding a fluororesin film) provided with a moisture-proof layer on the light incident surface side as a covering material.

[0002]

2. Description of the Related Art In recent years, attention has been paid to solar cells as a clean energy source without environmental pollution due to increasing awareness of environmental problems, and earnestly studied and practically used from the viewpoint of utilizing solar energy as a useful energy resource. .
There are various types of solar cells, and typical ones are crystalline silicon solar cells, polycrystalline silicon solar cells,
BACKGROUND ART Amorphous silicon solar cells, copper indium selenide solar cells, compound semiconductor solar cells, and the like are known. Among them, thin-film crystalline solar cells, amorphous silicon solar cells, and compound semiconductor solar cells are relatively low-cost and can be made large-area, and are being actively researched and developed in various fields. Among these solar cells, thin-film solar cells, such as amorphous silicon solar cells, in which silicon is deposited on a conductive metal substrate and a transparent conductive layer is further formed thereon, are lightweight, and have a high impact resistance. Because of its high flexibility, it is promising as a future module form in solar cells.

However, in the above-mentioned thin-film solar cell, unlike the case where silicon is deposited on a glass substrate, it is necessary to cover the light incident side surface with a transparent coating material to protect the solar cell. As the surface covering material, a transparent fluoride polymer 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 plastics with high weather resistance are used is that it is possible to suppress a decrease in conversion efficiency of the solar cell module due to a decrease in light transmittance due to deterioration. JP-A-5-283727 discloses a solar cell module in which at least one surface of a fluororesin film is coated with a transparent inorganic compound to prevent a decrease in the output of the solar cell due to the effect of moisture, thereby improving moisture resistance. Has been proposed. However, the fluorine film used here is very expensive, which is one of the reasons why the cost of the solar cell does not decrease.In addition, among the inorganic compounds to be coated, for example, when the silicon oxide is coated by a sputtering method, the inorganic compound generated Has a drawback that the conversion efficiency of the solar cell module is reduced due to a decrease in light transmittance due to dark brown color.

[0004]

SUMMARY OF THE INVENTION The object of the present invention is to solve the above-mentioned problems, that is, to improve the moisture proof property without lowering the transparency and the conversion efficiency, and at the same time, to increase the moisture proof property, thereby excluding very expensive fluororesin films. An object of the present invention is to provide a solar cell module using a weather-resistant plastic material as a covering material.

[0005]

SUMMARY OF THE INVENTION The present invention provides a conductive substrate,
Mainly back electrode, semiconductor layer, transparent electrode layer and current collecting electrode
Of photovoltaic cells including photovoltaic elements configured as
Plastic film covering the entrance surface (fluororesin
(Excluding film) on one or both sides
Depending on the operation, SiOx (X = greater than 1.0 and less than 2.0)
Silicon oxide represented by: metal fluoride = 98 to 80 m
%: A thin film composed of a compound having a composition ratio of 2 to 20 mol%
By layer or SiOx (X = greater than 1.0 and less than 2.0)
Expressed silicon oxide: metal fluoride: magnesium acid
Compound: 97.5 to 80 mol%: 2 to 19.5 mol%:
A thin film layer composed of a compound having a composition ratio of 0.5 to 18 mol%
This can be achieved by a formed solar cell module.
The present invention will be described more specifically. The solar cell module has a main component of a plastic film / plastic film in which a backside reinforcing plate / parallelized photovoltaic element provided by an adhesive / thin film layer is laminated. In addition, even in the case of a solar cell module whose surface is covered with a plastic film having a thin film layer laminated on the side opposite to the light incident side, a plastic film having a thin film layer laminated on the light incident side may be used. Of course, it is also possible to cover the solar cell with a plastic film having thin film layers laminated on both sides.

[0006] By laminating a thin film layer on one or both surfaces of the plastic film, it is possible to suppress the invasion of moisture from the outside and reduce the output reduction of the solar cell. Therefore, the output of the solar cell can be stably obtained even with light irradiation in a high humidity atmosphere. As the photovoltaic element used in the present invention, an element manufactured from a known amorphous silicon or a compound semiconductor by a known method is used. As the back reinforcing plate, a metal plate such as a stainless steel plate or an aluminum plate is mainly used. However, a weather-resistant plastic material having a thin film layer like the light incident surface can also be used.

The adhesive layer is made of a vinyl acetate ethylene copolymer (E
VA) a resin, an ionomer resin, an ethylene ethyl acrylate copolymer (EEA) resin, an ethylene methacrylic acid random copolymer (EMAA) resin, an ethylene acrylic acid copolymer (EAA) resin, an ethylene methyl methacrylate copolymer ( EMMA) resin, ethylene methyl acrylate copolymer (EMA) resin, and other adhesive polyolefin resins can be used. E in terms of weather resistance and transparency
VA resins and ionomer resins are preferred. Examples of the weather-resistant plastic film include films of polyethylene terephthalate, polycarbonate, polyethylene 2,6-naphthalenedicarboxylate, polysulfone, polyacrylate, polyethersulfone, polyarylate, polyetherimide, and polyallylsulfone. Can be used. In addition, they are mixed in these films and / or
The UV absorber to be applied is not particularly limited, but is a salicylic acid UV absorber, a benzophenone UV absorber, a benzotriazole UV absorber, a cyanoacrylate UV absorber, a UV stabilizer, a hindered amine light stabilizer. And the like, but is not limited thereto.

As a method for obtaining a thin film layer used in the present invention, SiOx (X = greater than 1.0) is applied to the surface of a weather-resistant plastic film by using a vacuum thin film forming technique .
0): metal fluoride = 98
~ 80 mol%: a compound having a composition ratio of 2 to 20 mol%.
Thin film layer or SiOx (X is larger than 1.0 and 2.0
Silicon oxide: metal fluoride: magnesi
Oxide = 97.5-80 mol%: 2-19.5 mol
%: A thin film composed of a compound having a composition ratio of 0.5 to 18 mol%
Form a layer. The silicon oxide that forms the thin film layer is SiOx
(X = greater than 1.0 and less than 2.0), and SiO,
Si ₂ O ₃ and Si ₃ O ₄ are included in this. X in SiOx is
The range is larger than 1.0 and smaller than 2.0, and particularly, x is preferably larger than 1.8 and smaller than 2.0. Examples of the metal fluoride forming the thin film layer include beryllium fluoride, magnesium fluoride, calcium fluoride, strontium fluoride, barium fluoride, aluminum fluoride, lithium fluoride, sodium fluoride, potassium fluoride, and fluoride. Rubidium fluoride, cesium fluoride, furanium fluoride and the like. In particular, fluorides of alkaline earth metals are excellent, and among them, magnesium fluoride and calcium fluoride are particularly excellent.

Examples of the magnesium oxide constituting the thin film layer include magnesium oxide, a co-oxide of magnesium oxide and silicon dioxide called forsterite and steatite, and a composite compound of magnesium oxide and metal fluoride. No. When the metal fluoride is an alkaline earth metal fluoride, SiOx (x is 1.0
Larger than 2.0) and a fluoride of an alkaline earth metal, or SiOx (x is larger than 1.0,
(Less than 2.0) the fluoride of alkaline earth metal and magnesium oxide are compounded. That is, the thin film layer is made of 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 larger than 1.0, 2.0
-) The thin film layer of metal fluoride is excellent in both moisture-proof property and light-transmitting property, but particularly excellent in light-transmitting property, and SiOx (x is larger than 1.0 and smaller than 2.0)-metal fluoride-oxidation The magnesium thin film layer is also excellent in moisture proof and light transmittance, but is particularly excellent in moisture proof. SiO constituting the thin film layer
x (x is greater than 1.0 and less than 2.0) and the composition ratio of metal fluoride are 98 to 80 mol% and 2 to 20 mol%, respectively.
Mol% is desirable, and particularly preferably, 95-90 mol% and 5-10 mol%, respectively. When magnesium oxide is contained therein, SiOx (x is 1.0
Larger, less than 2.0), and the composition ratio of the metal fluoride and the magnesium oxide is preferably in the range of 97.5 to 80 mol%: 2 to 19.5 mol%: 0.5 to 18 mol%. , Especially 93-88 mol%: 5-10 mol%: 2
The range of about to 17 mol% is desirable.

The raw material of the thin film layer laminated on the plastic film may be any one of an inorganic compound such as a metal oxide, a metal fluoride, a metal, an organometallic compound, and an organic compound, or a mixture thereof. In particular, using 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 as raw materials, a thin film layer is directly formed on a plastic film by vacuum evaporation or the like. Is desirable. The composition ratio of the raw materials is as follows: in the case of silicon oxide and metal fluoride, silicon oxide: metal fluoride = 98 to 70 mol%: 2 to 30 mol%
Is desirable. Particularly preferably, silicon oxide: metal fluoride = 95 to 85 mol%: 5 to 15 mol%. In the case of a mixture of silicon oxide, metal fluoride and a co-oxide of silicon dioxide and magnesium oxide,
Silicon oxide: Metal fluoride: Cooxide of silicon dioxide and magnesium oxide = 97.5 to 70 mol%: 2-2
9.5 mol%: a range of 0.5 to 28 mol% is desirable.
Particularly preferably, silicon oxide: metal fluoride: a co-oxide of silicon dioxide and magnesium oxide = 95 to 90 mol%: 4.5 to 9.5 mol%: 0.5 to 5.5 mol% Range.

Examples of the silicon oxide used as a raw material include a mixture of silicon and silicon dioxide, silicon monoxide alone, and a mixture of silicon, silicon dioxide and silicon monoxide. When silicon oxide is used as a mixture of silicon (Si) and silicon dioxide (SiO ₂ ), the composition ratio at that time is preferably basically equimolar, but Si: Si
O ₂ = 40 to 60% by mole: 60 to 40% by mole. The silicon oxide used as a raw material is Si, 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.

The method of forming a thin film layer on a plastic film may be either a continuous winding method or a single-wafer method. The method of forming the thin film layer is not particularly limited. A PVD method such as sputtering, or a CVD method such as plasma CVD or microwave CVD can be used. Further, there is no particular limitation on the heating method of the vacuum evaporation, as long as the evaporation splash called a splash does not occur during the evaporation and it is small enough to be removed without any trouble. Conventional heating 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 vaporized droplet is generated, the droplet remains as a foreign substance on the vapor deposited film,
Many problems occur in the subsequent steps such as an emulsion coating step, an exposure step, and a development step. A general crucible method may be used as an evaporation source for vacuum deposition, but a substance having a different sublimation point and melting point can be vacuum-deposited uniformly at all times.
And a system for continuously supplying and discharging the evaporation raw material described in JP-A-2-277774.

The degree of vacuum when vacuum-depositing 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 1 5 × from × 10 ^-4 torr
It is preferably within the range of 10 ^-3 torr. For high vacuum,
The composition of the raw material can be directly reflected on the composition of the thin film layer. Conversely, when the degree of vacuum is low, the composition of the thin film layer becomes excessive in oxygen atoms (high oxidation degree) as compared with the composition of the raw material.
This is considered to be a reaction between vapor deposition particles and oxygen atoms during vapor deposition. Further, it is estimated that a high-density thin film layer is obtained when the degree of vacuum is high, and a low-density film is obtained when the degree of vacuum is low. By using a raw material having the above composition and a degree of vacuum within the above range, a desired composition ratio for the thin film layer can be obtained.

Other methods of laminating a thin film layer include a method of vacuum deposition while oxidizing or fluorinating a compound containing a metal such as a metal or an organometallic compound, and a method of depositing a metal fluoride on a plastic film as a vapor-deposited layer. There is a method in which the deposited layer is oxidized in a post-process. The method of the oxidation treatment is not particularly limited as long as the treatment is performed 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 to be used. In the present invention, the thickness is preferably 50 to 2500 angstroms per side. In particular, 300 to 1200 Å is desirable. The thin film layers to be stacked may be double stacked or multiple stacked as long as the required functions of the finally obtained layer are obtained. That is, the lamination may be performed two or more times, and at that time, different kinds of metal fluorides may be laminated.

As an example of the method of manufacturing 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 producing by laminating by heating for a predetermined time is adopted. The adhesive layer of the plastic film formed by laminating the thin film layers of the present invention is mainly made of a transparent resin such as vinyl acetate-ethylene copolymer, polyvinyl butyral, silicone resin, epoxy resin, fluorinated polyimide resin, acrylic resin, and polyester resin. Use an adhesive as a component. The adhesive preferably contains a crosslinking agent, and preferably contains an ultraviolet absorber in order to suppress light deterioration of the adhesive.

Further, in order to reduce a decrease in the photoelectric conversion efficiency of the solar cell module, the light transmittance of the adhesive layer is desirably 80% or more in a wavelength region of 400 nm or more. Further, 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 the reflection of the incident light. As an example, the photovoltaic element used in the solar cell module of the present invention is composed of a conductive substrate / a back electrode / a semiconductor layer as a photoelectric conversion member / a transparent electrode layer / a current collecting electrode. The back electrode layer can also serve as a conductive substrate. Examples of the conductive substrate include stainless steel, aluminum, copper, titanium, carbon sheets, galvanized steel sheets, and resin films such as polyimide, polyester, polyethylene naphthalate, and epoxy having a conductive layer formed thereon, and ceramics. No.

As the semiconductor layer, for example, a compound semiconductor such as amorphous silicon, crystalline silicon, or copper indium selenide is preferably used.
An in junction, a pn junction, and a Schottky junction are used. In the case of using amorphous silicon, for example, it is formed by plasma CVD using silane gas or the like, and in the case of polycrystalline silicon, for example, it is formed by sheeting molten silicon or heat-treating amorphous silicon. CuInSe
_In the case of ₂ / CdS, 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). In addition, a resistance heating method of continuously supplying and discharging the evaporation raw material described in JP-A-1-252768 and JP-A-2-277774 may be used.

The semiconductor layer has a structure sandwiched between at least the back electrode layer and the transparent conductive layer. For the back electrode, a metal layer or a metal oxide layer, or a composite layer of a metal layer and a metal oxide layer is used. 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 and the} like are adopted. The metal layer and the metal oxide layer may be formed by, for example, electron beam evaporation, resistance heating evaporation, high frequency induction heating evaporation, sputtering, ion plating, electrodeposition (deposition by electrolysis of an electrolytic solution), or the like. I do. Further, Japanese Patent Laid-Open No.
A resistance heating method of continuously supplying and discharging the evaporation material described in JP-A-252768 and JP-A-2-277774 may be used.

As the material used for the transparent electrode layer, 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 , a crystalline semiconductor layer doped with a high concentration impurity, 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). Also, Japanese Patent Application Laid-Open Nos. 1-2252768 and 2-277
774, a resistance heating method of continuously supplying and discharging the evaporation raw material may be used. It is formed by a method such as electron beam evaporation, resistance heating evaporation, high-frequency induction heating evaporation, sputtering, ion plating, spraying, CVD, and impurity diffusion. In addition, Japanese Patent Application Laid-Open No. 1-252768
Alternatively, a resistance heating method of continuously supplying and discharging the evaporation raw material described in JP-A-2-277774 may be used.

The photovoltaic element is manufactured by forming a back electrode layer, a semiconductor layer, and a transparent electrode layer in this order on a conductive substrate, and then forming a current collecting electrode. As a material of the current collecting grid electrode, for example, Ti, Cr, Mo, W, Al, Ag, N
Metals such as i, Cu, Sn, Au, and Pd and conductive pastes such as silver paste are used. The grid electrode may be formed by, for example, sputtering using a mask pattern, ion plating, resistance heating, high-frequency induction heating, a CVD deposition method, a method in which a metal layer is deposited on the entire surface, followed by etching and patterning, or photo-CVD. There are a method of directly forming a grid electrode pattern, a method of forming a mask of a negative pattern of a grid electrode pattern and then forming the same by plating, a method of printing a conductive paste, and the like. When silver is not used for the grid electrode material, a silver paste is used as a conductive adhesive for bonding the grid electrode and the current collecting bus bar.

The conductive paste is usually, for example, silver, gold,
What disperse | distributed the fine powder metal, such as copper, nickel, and carbon, in the 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, for example, various insulating resins, ceramics, glass, an aluminum-coated film on an insulated metal substrate, silicon oxide, metal fluoride and / or magnesium oxide may be used. Polyethylene terephthalate, polycarbonate, polyethylene-2,6-naphthalenedicarboxylate, polysulfone, polyacrylate, polyethersulfone, polyarylate, polyetherimide, polyallylsulfone, fluororesin film having a thin film layer formed of Are used.

[0023]

Although the water vapor permeability of the plastic film provided with the vapor-deposited thin film layer according to the present invention has been reduced to one-tenth, no deterioration in the light transmittance has been observed at all, and the light incident on the solar cell has not been observed. It was an ideal material to cover the surface.

[0024]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the present invention is limited thereto. (Light Transmittance Measurement Method): The light transmittance at 400 nm was measured using a spectrophotometer (U-best30, manufactured by JASCO Corporation) using air as a reference. (Method for measuring moisture resistance): PERMATRAN manufactured by Modern Controls, USA, in accordance with ASTM F1249.
The water vapor transmission rate was measured using -W-TWIN. The smaller this value, the better the moisture resistance. (Solar cell output test): The produced solar cell module was irradiated with light of 100 mW / cm 2 and the electromotive force output was measured. (Exposure test): The surface-coated solar cell module was irradiated with light of AM 1.5 100 mW / cm ² using an environmental tester, under the conditions of low temperature −40 ° C. to high temperature 85 ° C. and relative humidity 85%. Perform 10 cycles of temperature and humidity,
AM1.5 100mW / cm for photovoltaic element after test
The light irradiation of No. 2 was performed, and the electromotive force output was measured. Example 1 Polyethylene terephthalate (manufactured by Tetron HB Teijin Limited) kneaded with a 25 μm thick ultraviolet absorbent was disclosed in
A mixture of 90 mol% to 10 mol% of silicon monoxide and magnesium fluoride was deposited using a resistance heating type vacuum evaporation machine of a type that continuously supplies and discharges the evaporation raw material shown in 252768, and the thickness was 600 Å. Were laminated.

The light transmittance and moisture resistance of this film were determined.
It was measured. Table 1 shows the results. Next, amorphous silicon (a
-Si) photovoltaic element was prepared. 0.15 washed
Using a sputtering method on a thick stainless steel substrate,
As electrodes, Al film thickness 500 nm, ZnO film thickness 500 n
m were sequentially formed. Next, by plasma CVD, the Si
H_FourAnd PH_ThreeAnd H_TwoThe n-type a-Si layer from SiH_FourAnd H _Two
The i-type a-Si layer from SiH_FourAnd BF_ThreeAnd H_TwoTo p-type
A microcrystalline μc-Si layer is formed, and an n-layer thickness of 15 nm / i layer
400 nm / p-layer thickness 10 nm / n-layer thickness 10 nm
/ I layer thickness of 80 nm / p layer thickness of 10 nm
After forming the conductor layer, use an ITO target as a transparent electrode.
Was sputtered to form an ITO film having a thickness of 700 nm.

Next, a silver paste (Rexbond T-700, manufactured by Toyo Ink Mfg. Co., Ltd.) was printed in a grid pattern using a screen printer, and then heat-treated at 125 ° C. to form a current collecting electrode. A power element was created. A predetermined size was cut out from the polyethylene terephthalate kneaded with an ultraviolet absorber obtained by laminating silicon monoxide and magnesium fluoride, and was used as a covering material for a solar cell module. As a transparent adhesive, a sheet-like EVA formed by adding a crosslinking agent and an ultraviolet absorber was used. As the backing material, an insulated zinc steel sheet was used.

After the photovoltaic elements produced by the above method are connected in series and parallel so that a predetermined output can be obtained, the thin film layer of the polyethylene terephthalate film incorporating the ultraviolet absorbent is arranged so as to be in contact with the adhesive EVA102. hand,
After the ultraviolet absorber kneaded polyethylene terephthalate film having a thin film layer formed thereon from light incidence / EVA / photovoltaic element / EVA / insulated zinc steel plate is layered in order, then put in a vacuum laminator and evacuated to about 1 Torr. Under a pressure of atmospheric pressure, the solar cell was heated at 140 ° C. for 30 minutes to coat the surface of the solar cell. However, the output terminal of the solar cell was previously taken out by making a hole for the output terminal in a zinc steel plate as a backing material.

A solar cell output test was performed on the obtained surface-coated solar cell module. Next, an exposure test was performed. Table 1 shows the results. Example 2 Polyethylene naphthalate (manufactured by Teonex Teijin Limited) kneaded with an ultraviolet absorber having a thickness of 12 μm was disclosed in
No. 52768, using a vacuum evaporation machine of a resistance heating system of continuously supplying and discharging the evaporation material, silicon, silicon dioxide, calcium fluoride and forsterite (mixing ratio: 45 mol% / 45 mol) % / 8 mol% / 2 mol% of the mixture was deposited and a 600 Å thin film was deposited.

The light transmittance and moisture resistance of this film were measured. Table 1 shows the results. The method of modularizing the solar cell and coating the surface was performed in the same manner as in Example 1.
A solar cell output test was performed on the obtained surface-coated solar cell module. Next, an exposure test was performed. Table 1 shows the results. Comparative Example 1 A mixture of silicon monoxide and magnesium fluoride in Example 1 was not vacuum-deposited, and the same procedure as in Example 1 was performed thereafter. Table 1 shows the results. Comparative Example 2 Using the polyethylene terephthalate kneaded with the ultraviolet absorbent of Example 1, a mixture of silicon monoxide and magnesium fluoride was used instead of vacuum deposition, and only silicon monoxide was used for 600 minutes.
Angstrom thin films were sputtered. Thereafter, the same operation as in Example 1 was performed. Table 1 shows the results.

Comparative Example 3 An ETFE fluororesin film (manufactured by Daikin), which is a fluororesin film, was used in place of polyethylene terephthalate in which the ultraviolet absorbent was kneaded in Example 1, and a mixture of silicon monoxide and magnesium fluoride was vacuum-deposited. instead of,
Only silicon monoxide was sputtered into a 600 Å thin film. Thereafter, the same operation as in Example 1 was performed. Table 1 shows the results.

[0031]

[Table 1]

Claims (6)

(57) [Claims] 1. A plastic film (fluororesin-based) for 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. SiOx (X = 1.2 ) on one or both sides of the film (excluding film) by vacuum thin film formation technology .
Silicon oxide represented by greater than 0 and less than 2.0):
Metal fluoride = 98 to 80 mol%: 2 to 20 mol%
A solar cell module comprising a thin film layer formed of a compound having a composition ratio . 2. A plastic film (fluororesin-based resin) 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. SiOx (X = 1.2 ) on one or both sides of the film (excluding film) by vacuum thin film formation technology .
Silicon oxide represented by greater than 0 and less than 2.0):
Metal fluoride: magnesium oxide = 97.5 to 80 m
%: 2 to 19.5 mol%: 0.5 to 18 mol%
A solar cell module comprising a thin film layer formed of a compound having a specific ratio . 3. The solar cell module according to claim 1, wherein the metal fluoride forming the thin film layer is at least one selected from magnesium fluoride and calcium fluoride. 4. The magnesium oxide constituting the thin film layer is one or more selected from magnesium oxide, a co-oxide of magnesium oxide and silicon dioxide, and a composite compound of magnesium oxide and metal fluoride. The solar cell module according to claim 2. 5. The plastic film constituting the solar cell module is made of polyethylene terephthalate, polycarbonate, polyethylene-2,6-naphthalenedicarboxylate, polysulfone, polyacrylate, polyethersulfone, polyarylate, polyetherimide, polyallylsal. The solar cell module according to claim 1 or 2, which is a phone. 6. The solar cell module according to claim 1, wherein the plastic film constituting the solar cell module is mixed and / or coated with an ultraviolet absorbent.