JP2010177398A - Sealing film for solar cell, and solar cell using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sealing film for solar cells which is superior in electric insulation though containing a coloring agent. <P>SOLUTION: The sealing film for solar cells contains an ethylene-unsaturated ester copolymer, a cross-linking agent and a coloring agent, and the coloring agent is composed of a bivalent metal oxide and has a volume resistivity of 1.0×10<SP>13</SP>to 5.0×10<SP>14</SP>Ωcm at 60°C after cross-linking and curing. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a solar cell sealing film that is excellent in both electrical insulation and light reflectivity.

  In recent years, solar cells that convert sunlight into electrical energy have attracted attention and are being developed from the viewpoint of effective use of resources and prevention of environmental pollution.

  As shown in FIG. 1, the solar cell generally has a surface-side transparent protective member 11 made of a glass substrate or the like, a surface-side sealing film 13A, a solar battery cell 14 such as a silicon power generation element, a back-side sealing film 13B, And the back-side protection member (back cover) 12 are laminated in this order, deaerated under reduced pressure, and heated and pressurized to cross-link and cure the front-side sealing film 13A and the back-side sealing film 13B to be integrated. It is manufactured by. In a conventional solar battery, a plurality of solar battery cells 14 are connected and used in order to obtain a high electric output. Therefore, the solar cell is sealed using the sealing films 13A and 13B having insulating properties. Thereby, it is possible to prevent electricity leakage inside the solar cell and reliably extract the generated electricity via the wiring.

  The sealing film used on the front side and the back side is preferably a film made of an ethylene-unsaturated ester copolymer such as an ethylene vinyl acetate copolymer (EVA) film or an ethylene ethyl acrylate copolymer (EEA) film. (Patent Document 1).

  In the sealing film, in order to improve film strength and durability, a cross-linking structure is imparted to the ethylene-unsaturated ester copolymer using a cross-linking agent such as an organic peroxide. Furthermore, crosslinking aids such as triallyl isocyanurate and triallyl isocyanate are also used in order to improve the gel fraction of the ethylene-unsaturated ester copolymer and improve durability.

  In the solar cell, it is strongly desired from the viewpoint of improving power generation efficiency that light incident on the solar cell can be taken into the solar cell as efficiently as possible. Therefore, it is desirable that the sealing film has transparency as high as possible, does not absorb or reflect incident sunlight, and transmits most of sunlight.

Further, Patent Document 1 discloses a solar cell using an EVA film colored with a colorant such as titanium white (TiO ₂ ) as a back side sealing film in order to improve power generation efficiency. According to the sealing film colored in this manner, the reflection of light at the interface between the front surface side sealing film and the rear surface side sealing film inside the solar cell or the irregular reflection of light by the colorant itself, Light incident between them or light that has passed through the cell can be diffusely reflected and incident on the cell again. Thereby, the utilization efficiency of the light incident on the solar cell is increased, and the power generation efficiency of the solar cell can be improved.

Japanese Patent Laid-Open No. 06-177412

  However, simply adding a colorant to the solar cell sealing film may reduce the electrical insulation of the sealing film, and may not sufficiently improve the power generation efficiency of the solar cell.

  Accordingly, an object of the present invention is to provide a solar cell sealing film that is excellent in electrical insulation even if it contains a colorant.

The present invention is a solar cell encapsulating film comprising an ethylene-unsaturated ester copolymer, a crosslinking agent, and a colorant,
The colorant comprises a divalent metal oxide;
The above problems are solved by a sealing film for solar cells, wherein the volume resistivity value in an atmosphere at 60 ° C. is 1.0 × 10 ^{13 to} 5.0 × 10 ¹⁴ Ω · cm.

  Below, the suitable aspect of the sealing film for solar cells of this invention is enumerated.

  (1) The divalent metal oxide is at least one selected from the group consisting of zinc oxide, magnesium oxide, and calcium oxide.

  (2) The refractive index of the colorant is 1.9 to 2.1.

  (3) The content of the colorant is in the range of more than 10 parts by weight and 30 parts by weight or less with respect to 100 parts by weight of the ethylene-unsaturated ester copolymer.

  According to the present invention, by using a divalent metal oxide as a colorant, a solar cell sealing film excellent in electrical insulation can be obtained. Therefore, by using such a solar cell sealing film, it is possible to prevent the leakage of electricity inside the battery, increase the utilization efficiency of incident light, and improve the power generation efficiency of the solar cell. Furthermore, the solar cell has excellent safety and reliability by reducing risks such as electric leakage.

It is sectional drawing of a solar cell.

  The solar cell sealing film of the present invention contains at least an ethylene-unsaturated ester copolymer, a crosslinking agent, and a colorant as basic components. In particular, by using a divalent metal oxide as the colorant, a solar cell sealing film having excellent electrical insulation can be obtained even when the colorant is contained. This is presumably because in the case of a divalent metal oxide, it is difficult for the bias to occur and the ionicity becomes low.

Therefore, the sealing film for solar cells of the present invention has a volume resistivity value of 1.0 × 10 ^{13 to} 5.0 × 10 ¹⁴ Ω.multidot. cm, preferably 1.5 × 10 ^{13 to} 5.0 × 10 ¹⁴ Ω · cm, more preferably 2.0 × 10 ^{13 to} 5.0 × 10 ¹⁴ Ω · cm, and excellent electrical insulation. Have.

  The colorant is made of a divalent metal oxide. Preferably, a metal oxide represented by the general formula: MO (wherein M represents a divalent metal element) can be used. Examples of the divalent metal include beryllium (II), calcium (II), manganese (II), iron (II), cobalt (II), nickel (II), zinc (II), and cadmium (II). It is done. As the divalent metal oxide, zinc oxide (ZnO), magnesium oxide (MgO), and calcium oxide (CaO) are preferable, and zinc oxide is particularly preferable. These may be used alone or in combination of two or more.

  The refractive index of the colorant is preferably 1.9 to 2.1, particularly 1.95 to 2.0. Thereby, light can be highly irregularly reflected and excellent electrical insulation can be imparted to the sealing film.

  In addition, the refractive index of the coloring agent in the sealing film for solar cells is measured by using a light interference type film thickness measuring device [Lambda Ace VM-1000, manufactured by Dainippon Screen Co., Ltd.] JIS K7142-1996 (B Method; measurement wavelength 589 nm).

  The content of the colorant in the solar cell sealing film is preferably more than 10 parts by weight and 30 parts by weight or less, more preferably 15 to 30 parts by weight, with respect to 100 parts by weight of the ethylene-unsaturated ester copolymer. Especially preferably, it is 15-25 mass parts. Thereby, the electrical insulation of the solar cell sealing film can be further improved.

  The average particle diameter of the colorant is preferably 1 nm to 5 μm, more preferably 0.1 to 2.5 μm. If it is a coloring agent which has such an average particle diameter, it can be highly disperse | distributed in a sealing film, and both the electrical insulation of a sealing film and light reflectivity can be improved.

  In the present invention, the average particle diameter of the colorant is the number obtained by observing the cross section of the sealing film with a transmission electron microscope at a magnification of about 1,000,000 times, and obtaining the projected area equivalent circle diameter of at least 100 colorants. Average value.

  The whiteness of the sealing film for a solar cell colored with a white colorant, particularly zinc oxide, is preferably 50 to 70, particularly 60 to 70. Thereby, the sealing film which has the outstanding light diffusibility is obtained.

  The solar cell sealing film of the present invention contains an ethylene-unsaturated ester copolymer as an organic resin. Examples of the unsaturated ester monomer of the ethylene-unsaturated ester copolymer include methyl acrylate, ethyl acrylate, isobutyl acrylate, n-butyl acrylate, isooctyl acrylate, methyl methacrylate, isobutyl methacrylate, malee. Examples thereof include unsaturated carboxylic acid esters such as dimethyl acid and diethyl maleate, and vinyl esters such as vinyl acetate and vinyl propionate.

  Among these, the ethylene-unsaturated ester copolymer is preferably an ethylene-vinyl acetate copolymer (EVA). The colorant having the above-described refractive index in the EVA film can reflect incident light particularly highly.

  The vinyl acetate content of the ethylene-vinyl acetate copolymer is preferably 20 to 35 parts by mass, more preferably 20 to 30 parts by mass, particularly preferably 100 parts by mass of the ethylene-vinyl acetate copolymer. 24 to 28 parts by mass. Thereby, the sealing film which is excellent in film forming property and excellent in electrical insulation can be obtained.

  As the cross-linking agent used in the solar cell sealing film of the present invention, an organic peroxide is preferably used. Any organic peroxide can be used as long as it decomposes at a temperature of 100 ° C. or higher and generates radicals. The organic peroxide is generally selected in consideration of the film formation temperature, the adjustment conditions of the composition, the curing temperature, the heat resistance of the adherend, and the storage stability. In particular, a decomposition temperature of a half-life of 10 hours is preferably 70 ° C. or higher, particularly 80 to 120 ° C.

  Examples of the organic peroxide include 2,5-dimethylhexane; 2,5-dihydroperoxide; 2,5-dimethyl-2, from the viewpoint of compatibility with the ethylene-unsaturated ester copolymer. 5-di (tert-butylperoxy) hexane; 3-di-tert-butyl peroxide; tert-dicumyl peroxide; 2,5-dimethyl-2,5-bis (2-ethylhexanoylperoxy) hexane 2,5-dimethyl-2,5-bis (tert-butylperoxy) hexane; 2,5-dimethyl-2,5-di (tert-butylperoxy) hexyne; dicumyl peroxide; tert-butylcumi Luperoxide; α, α′-bis (tert-butylperoxyisopropyl) benzene; α, α′-bis (tert-butylper) Xyl) diisopropylbenzene; n-butyl-4,4-bis (tert-butylperoxy) butane; 2,2-bis (tert-butylperoxy) butane; 1,1-bis (tert-butylperoxy) cyclohexane 1,1-bis (tert-hexylperoxy) trimethylcyclohexane; 1,1-bis (tert-butylperoxy) 3,3,5-trimethylcyclohexane; tert-butylperoxybenzoate; benzoyl peroxide, etc. Preferably mentioned. These may be used individually by 1 type, and 2 or more types may be mixed and used for them.

  Among the organic peroxides, a sealing film for solar cells having excellent electrical insulation can be obtained, so that 2,5-dimethyl-2,5-bis (tert-butylperoxy) hexane, , 5-dimethyl-2,5-bis (2-ethylhexanoylperoxy) hexane, 1,1-bis (tert-hexylperoxy) trimethylcyclohexane, and 1,1-bis (tert-butylperoxy) 3 It is particularly preferred to use 3,3,5-trimethylcyclohexane.

  The content of the crosslinking agent in the sealing film is preferably 0.1 to 5 parts by mass, more preferably 0.2 to 1.5 parts by mass with respect to 100 parts by mass of the ethylene-unsaturated ester copolymer. is there. Thus, in the sealing film of this invention, content of the organic peroxide which is a crosslinking agent can be decreased very much by using the above-mentioned crosslinking adjuvant. Thereby, deterioration of the ethylene-unsaturated ester copolymer due to the organic peroxide is suppressed, and the heat resistance of the sealing film can be improved.

  The sealing film of the present invention improves or adjusts various physical properties of the film (optical properties such as mechanical strength, adhesiveness and transparency, heat resistance, light resistance, crosslinking speed, etc.), especially improvement of mechanical strength. Therefore, if necessary, various additives such as a plasticizer, an adhesion improver, an acryloxy group-containing compound, a methacryloxy group-containing compound and / or an epoxy group-containing compound may be further included.

  The plasticizer is not particularly limited, but polybasic acid esters and polyhydric alcohol esters are generally used. Examples thereof include dioctyl phthalate, dihexyl adipate, triethylene glycol-di-2-ethylbutyrate, butyl sebacate, tetraethylene glycol diheptanoate, and triethylene glycol dipelargonate. One type of plasticizer may be used, or two or more types may be used in combination. The content of the plasticizer is preferably in the range of 5 parts by mass or less with respect to 100 parts by mass of the ethylene-unsaturated ester copolymer.

  As the adhesion improver, a silane coupling agent can be used. Thereby, it becomes possible to form the sealing film for solar cells which has the outstanding adhesive force. Examples of the silane coupling agent include γ-chloropropylmethoxysilane, vinylethoxysilane, vinyltris (β-methoxyethoxy) silane, γ-methacryloxypropyltrimethoxysilane, vinyltriacetoxysilane, and γ-glycidoxypropyltrimethoxy. Silane, γ-glycidoxypropyltriethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, vinyltrichlorosilane, γ-mercaptopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-β Mention may be made of-(aminoethyl) -γ-aminopropyltrimethoxysilane. These silane coupling agents may be used alone or in combination of two or more. Moreover, it is preferable that content of the said adhesive improvement agent is 5 mass parts or less with respect to 100 mass parts of ethylene-unsaturated ester copolymers.

  The acryloxy group-containing compound and the methacryloxy group-containing compound are generally acrylic acid or methacrylic acid derivatives, and examples thereof include acrylic acid or methacrylic acid esters and amides. Examples of ester residues include linear alkyl groups such as methyl, ethyl, dodecyl, stearyl, lauryl, cyclohexyl group, tetrahydrofurfuryl group, aminoethyl group, 2-hydroxyethyl group, 3-hydroxypropyl group. Group, 3-chloro-2-hydroxypropyl group. Examples of amides include diacetone acrylamide. In addition, polyhydric alcohols such as ethylene glycol, triethylene glycol, polypropylene glycol, polyethylene glycol, trimethylolpropane, and pentaerythritol, and esters of acrylic acid or methacrylic acid can also be used.

Examples of the epoxy-containing compound include triglycidyl tris (2-hydroxyethyl) isocyanurate, neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, allyl glycidyl ether, 2-ethylhexyl glycidyl ether, phenyl glycidyl ether, Examples include phenol (ethyleneoxy) ₅ glycidyl ether, pt-butylphenyl glycidyl ether, adipic acid diglycidyl ester, phthalic acid diglycidyl ester, glycidyl methacrylate, and butyl glycidyl ether.

  The acryloxy group-containing compound, the methacryloxy group-containing compound, or the epoxy group-containing compound is generally 0.5 to 5.0 parts by weight, particularly 1. It is preferable that 0-4.0 mass parts is contained.

  Furthermore, the sealing film of the present invention may contain an ultraviolet absorber, a light stabilizer and / or an anti-aging agent.

  By including the ultraviolet absorber in the sealing film of the present invention, it is possible to suppress deterioration of the ethylene-unsaturated ester copolymer due to the influence of irradiated light and the like, and the solar battery sealing film from being yellowed. Can do. The ultraviolet absorber is not particularly limited, but 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-n-dodecyloxybenzophenone, 2,4-dihydroxybenzophenone, 2,2′-dihydroxy-4- Preferred examples include benzophenone-based ultraviolet absorbers such as methoxybenzophenone and 2-hydroxy-4-n-octoxybenzophenone. In addition, it is preferable that the compounding quantity of the said benzophenone series ultraviolet absorber is 0.01-5 mass parts with respect to 100 mass parts of ethylene-unsaturated ester copolymers.

  Even if the sealing film of the present invention contains a light stabilizer, the deterioration of the ethylene-unsaturated ester copolymer due to the influence of irradiated light or the like is suppressed, and the solar battery sealing film is prevented from yellowing. be able to. As the light stabilizer, a light stabilizer called a hindered amine type is preferably used. For example, LA-52, LA-57, LA-62, LA-63LA-63p, LA-67, LA-68 (all ( ADEKA Co., Ltd.), Tinuvin 744, Tinuvin 770, Tinuvin 765, Tinuvin 144, Tinuvin 622LD, CHIMASORB 944LD (all manufactured by Ciba Specialty Chemicals Co., Ltd.), UV-3034 (BF Goodrich) Can be mentioned. In addition, the said light stabilizer may be used individually or may be used in combination of 2 or more types, and the compounding quantity is 0.01-5 mass with respect to 100 mass parts of ethylene-unsaturated ester copolymers. Part.

  Examples of the antioxidant include hindered phenol antioxidants such as N, N′-hexane-1,6-diylbis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionamide]. , Phosphorus heat stabilizers, lactone heat stabilizers, vitamin E heat stabilizers, sulfur heat stabilizers, and the like.

  Although the thickness in particular of the sealing film for solar cells is not restrict | limited, What is necessary is just the range of 50 micrometers-2 mm.

  What is necessary is just to perform according to a well-known method in order to form the sealing film for solar cells of this invention mentioned above. For example, the composition containing each of the above-described components can be produced by a method of obtaining a sheet-like product by molding by ordinary extrusion molding, calendar molding (calendering), or the like. When a film is formed by heat rolling using extrusion molding or the like, heating is generally in the range of 50 to 90 ° C.

  At this time, since high dispersibility of the colorant is obtained, a masterbatch is prepared by previously mixing a high concentration of colorant with the ethylene-unsaturated ester copolymer, and the above-described various components are further added to the masterbatch. It is preferable to mix to obtain the composition.

  Alternatively, a sheet-like material can be obtained by dissolving the composition in a solvent and coating the solution on a suitable support with a suitable coating machine (coater) and drying to form a coating film.

  As described above, the solar cell sealing film of the present invention is excellent in electrical insulation and light reflectivity. Therefore, by using such a solar cell sealing film for a solar cell, a solar cell capable of preventing electricity leakage inside the battery and having a high utilization rate of incident light can exhibit excellent power generation efficiency. can get. Furthermore, since the sealing film for solar cells of the present invention is particularly excellent in electrical insulation, the occurrence of electric leakage and insulation failure is remarkably reduced even in a high temperature environment of 50 ° C. or higher, and excellent safety and A solar cell having reliability can be provided.

  The structure of the solar cell using the solar cell sealing film according to the present invention is not particularly limited. However, the solar cell sealing film is interposed between the front surface side transparent protective member and the back surface side protective member to crosslink. Examples include a structure in which cells for solar cells are sealed by integration.

  In the solar cell, in order to sufficiently seal the solar cell, as shown in FIG. 1, the surface side transparent protective member 11, the surface side sealing film 13A, the solar cell 14 and the back surface side sealing film 13B. And the back surface side protection member 12 may be laminated | stacked, and the sealing film should just be bridge | crosslinked and hardened | cured according to conventional methods, such as heating and pressurization.

The cross-linking curing is preferably performed until the gel fraction of the sealing film reaches 80% by mass or more in order to obtain high sealing properties. In order to crosslink and cure the sealing film to such a gel fraction, for example, the laminate is heated at a temperature of 135 to 180 ° C., further 140 to 180 ° C., particularly 155 to 180 ° C. for 5 to 60 minutes with a vacuum laminator. You can heat with. The heating may be performed while pressing the laminate at a press pressure of 0.1 to 1.5 kg / cm ² , or the laminate is preheated at 80 to 100 ° C. for 1 to 20 minutes before the heating. Also good. Thus, by cross-linking the ethylene-unsaturated ester copolymer contained in the front side sealing film 13A and the back side sealing film 13B, the front side sealing film 13A and the back side sealing film 13B are interposed. The solar cell 14 can be sealed by integrating the front surface side transparent protective member 11, the back surface side transparent member 12, and the solar cell 14.

  In such a solar cell, the solar cell sealing film of the present invention may be used as at least one of the front surface side sealing film and the back surface side sealing film, but is used as the back surface side sealing film. Is preferred.

In a solar battery, the sealing film is crosslinked and cured in order to seal the cells. However, the solar battery sealing film of the present invention has excellent electrical insulation even after crosslinking and curing. For example, the sealing film for solar cells of the present invention has a volume resistivity value of 1.0 × in a 60 ° C. atmosphere even after the gel fraction is crosslinked and cured to 80% or more, particularly 80 to 95%. 10 ^{13 to} 5.0 × 10 ¹⁴ Ω · cm, and excellent electrical insulation can be exhibited even under a high temperature environment.

  In the present invention, the light receiving surface side with respect to the solar cell is referred to as “front surface side”, and the surface opposite to the light receiving surface of the solar cell is referred to as “back surface side”.

  The surface side transparent protective member used for the solar cell of the present invention is usually a glass substrate such as silicate glass. As for the thickness of a glass substrate, 0.1-10 mm is common, and 0.3-5 mm is preferable. The glass substrate may generally be chemically or thermally strengthened.

  The back surface side protective member used in the present invention is a plastic film such as PET. In consideration of heat resistance and moist heat resistance, a fluorinated polyethylene film, particularly a fluorinated polyethylene film / Al / fluorinated polyethylene film, in this order. The film laminated | stacked by may be sufficient.

  Hereinafter, the present invention will be described with reference to examples. In addition, this invention is not restrict | limited by a following example.

Example 1
The following materials were supplied to a roll mill and kneaded at 70 ° C. The composition thus obtained was calendered at 70 ° C. to produce a solar cell sealing film (thickness 0.6 mm).

100 parts by mass of an ethylene-vinyl acetate copolymer (25 parts by mass of vinyl acetate based on 100 parts by mass of EVA),
Colorant A (ZnO; refractive index 1.95) 10 parts by mass,
1 part by weight of a crosslinking agent (1,1-bis (tert-hexylperoxy) trimethylcyclohexane),
2 parts by mass of a crosslinking aid (triallyl isocyanurate) and 0.5 parts by mass of a silane coupling agent (γ-methacryloxypropyltrimethoxysilane).

(Examples 2 to 6)
In Examples 2 to 6, a solar cell sealing film was produced in the same manner as in Example 1 except that the blending amount of the colorant A (ZnO) was changed as shown in Table 1.

(Examples 7 to 10)
In Examples 7 to 10, in place of the colorant A, a colorant B (MgO; refractive index 1.70) was used for solar cells in the same manner as in Example 1 except that the compounding amounts shown in Table 1 were used. A sealing film was produced.

(Examples 11-14)
In Examples 11 to 14, instead of the colorant A, a colorant C (CaO; refractive index 1.55) was used in the same manner as in Example 1 except for using the compounding amounts shown in Table 2, respectively. A sealing film was produced.

(Comparative Example 1)
In Comparative Example 1, a solar cell sealing film was produced in the same manner as in Example 1 except that 4.5 parts by mass of Colorant D (TiO ₂ ; refractive index 2.76) was used instead of Colorant A. did.

(Evaluation)
The volume specific resistance and whiteness of each solar cell sealing film produced above were evaluated. In addition, these evaluation was performed using the glass joined body produced according to the following procedure using the sealing film for solar cells. The results are summarized in Table 1 and Table 2.

  A solar cell sealing film (size 50 mm × 50 mm) is made of white sheet glass (soda lime glass, thickness 3 mm, size 50 mm × 50 mm) using white sheet glass / solar cell sealing film / white plate. Lamination was performed in the order of glass. The obtained laminate was pressure-bonded at 90 ° C. for 2 minutes under vacuum with a vacuum laminator, and then heated for 45 minutes at a temperature of 155 ° C. As a result, a glass bonded body in which the sealing film was crosslinked and cured to a gel fraction of 80% or more was obtained.

(Volume resistivity)
Using a ring type electrode (UR-100 probe manufactured by Mitsubishi Chemical Corporation) and a high resistance meter (High Lester UPMCP-HT450 manufactured by Mitsubishi Chemical Corporation), a sealing film for solar cell after crosslinking curing in the glass bonded body A voltage of 1000 V was applied to the sample at a temperature of 60 ° C., the resistance value after 1 minute was measured, and the volume specific resistance value [Ω · cm] was calculated based on the measured value.

(Whiteness)
The whiteness of the glass joined body was measured using a color meter (SM-4 manufactured by Suga Test Instruments Co., Ltd.).

(Gel fraction)
1 g of the solar cell sealing film after crosslinking and curing is weighed and placed in an 80 mesh wire mesh bag. The sample with the wire mesh is put into the Soxhlet extractor, and xylene is refluxed at the boiling point. After 24 hours of continuous extraction, the entire wire mesh and the sample are taken out, dried, weighed, and compared with the weight before and after extraction to measure the mass% of the remaining insoluble matter, which is taken as the gel fraction.

11, 21 Surface side transparent protective member,
12, 22 Back side protective material,
13A surface side sealing film,
13B Back side sealing film,
14 Solar cell.

Claims (6)

A solar cell encapsulating film comprising an ethylene-unsaturated ester copolymer, a crosslinking agent, and a colorant,
The colorant comprises a divalent metal oxide;
After crosslinking and curing, a solar cell sealing film having a volume resistivity value of 1.0 × 10 ^{13 to} 5.0 × 10 ¹⁴ Ω · cm in a 60 ° C. atmosphere.   2. The solar cell sealing film according to claim 1, wherein the divalent metal oxide is at least one selected from the group consisting of zinc oxide, magnesium oxide, and calcium oxide.   The solar cell sealing film according to claim 1 or 2, wherein the colorant has a refractive index of 1.9 to 2.1.   The content of the colorant is in the range of more than 10 parts by mass and 30 parts by mass or less with respect to 100 parts by mass of the ethylene-unsaturated ester copolymer. The sealing film for solar cells of Claim 1.   5. The solar cell sealing film according to claim 1, wherein the ethylene-unsaturated ester copolymer is an ethylene-vinyl acetate copolymer.   A solar cell using the solar cell sealing film according to claim 1.

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