JP6013726B2 - A pair of sealing films for solar cells - Google Patents

Description

  The present invention relates to a pair of solar cell sealing films capable of preventing the back side colored sealing film from entering the power generating element light-receiving surface during the production of the solar cell module, and a solar cell module using the same. It relates to a manufacturing method.

  In recent years, solar cells that directly convert sunlight into electrical energy have been widely used and further developed in terms of effective use of resources and prevention of environmental pollution.

  Generally, a solar cell is configured such that a power generation element is sealed between a light-receiving surface side transparent protective member and a back surface-side protective member (back cover) by a light-receiving surface side sealing film and a back surface side sealing film. ing. A conventional solar cell is used as a solar cell module by connecting a plurality of power generating elements in order to obtain a high electric output. Therefore, an insulating sealing film is used to ensure insulation between the power generating elements.

  As the sealing film used on the light receiving surface side and the back surface side, an ethylene-vinyl acetate copolymer (EVA) film or the like is preferably used. Further, in order to improve the film strength and durability, the crosslinking density is improved by using a crosslinking agent such as an organic peroxide in addition to EVA for the sealing film.

  In the solar cell module, it is strongly desired from the viewpoint of improving the power generation efficiency that light incident on the solar cell module can be taken into the power generation element as efficiently as possible. Therefore, it is desirable that the light-receiving surface side sealing film does not absorb or reflect incident sunlight and transmits most of sunlight. Therefore, a sealing film excellent in transparency is used as the light-receiving surface side sealing film (for example, Patent Document 1).

On the other hand, as the back surface side sealing film, an EVA film colored with a colorant such as titanium dioxide (TiO ₂ ) is used (for example, Patent Document 2). According to the back side sealing film colored in this way, by reflection of light at the interface between the light receiving surface side sealing film and the back side sealing film inside the solar cell module, or by irregular reflection of light by the colorant itself, Light passing between the power generation elements can be incident on the power generation elements. Thereby, the utilization efficiency of the light incident on the solar cell module is increased, and the power generation efficiency of the solar cell module can be improved.

  To produce a solar cell module, as shown in FIG. 1, a plurality of power generation elements 14 electrically connected by a light-receiving surface side transparent protective member 11, a light-receiving surface-side sealing film 13 </ b> A, a connection tab 15, and the back surface side The sealing film 13B and the back surface side protection member 12 (back cover) are laminated in this order, and the light receiving surface side sealing film and the back surface side sealing film are crosslinked by pressurizing and heating the obtained laminated body 10. A method of curing and bonding and integrating the members is used.

  Bonding and integration of each member of the laminate 10 is generally performed using a vacuum laminator. As the vacuum laminator, for example, as shown in FIG. 2, a double vacuum chamber type vacuum laminator 100 including an upper chamber 102 having a diaphragm 103 and a lower chamber 101 provided with a mounting table 105 is used. . In the adhesive integration, the stacked body 10 is placed on the mounting table 105 so that the light-receiving surface side transparent protective member 11 is on the lower side, and then the upper chamber 102 and the lower chamber 101 are brought into a vacuum state, and the mounting table 105 is placed. The laminated body 10 is heated by a heater (not shown) built in, and the upper surface of the laminated body 10 is pressed by the diaphragm 103 while the upper chamber 102 is usually at a pressure higher than atmospheric pressure.

JP 2008-053379 A Japanese Patent Laid-Open No. 06-177412

  However, when pressing the laminated body, the pressure applied to the laminated body may become uneven, and as shown in FIG. 3, the back side colored sealing film 13 </ b> B melted by heating is formed on the light receiving surface of the power generation element 14. There was a case of intrusion (hereinafter, this phenomenon is referred to as “wraparound”). When the wraparound occurs, not only the appearance characteristics of the solar cell module are deteriorated, but also the sunlight incident on the power generation element is decreased and the power generation efficiency may be decreased.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a light-receiving surface-side sealing film and a back-surface side that can prevent the back-side colored sealing film from wrapping around the light-receiving surface of the power generation element. An object of the present invention is to provide a pair of solar cell sealing films made of a sealing film.

  Moreover, the objective of this invention is providing the manufacturing method of the solar cell module which can prevent a wraparound.

  Furthermore, an object of the present invention is to provide a solar cell module in which wraparound is prevented and deterioration in appearance and power generation efficiency is prevented.

The above object is a pair of solar cell sealing films for sealing the power generating element disposed between the light-receiving surface side transparent protective member and the back surface-side protective member from the light receiving surface side and the back surface side. The light receiving surface side sealing film disposed between the light receiving surface side transparent protective member and the power generation element includes an ethylene-vinyl acetate copolymer, and is disposed between the back surface side protective member and the power generation element. The back surface side sealing film contains an ethylene-vinyl acetate copolymer and a colorant, and the melt flow rate of the ethylene-vinyl acetate copolymer of the back surface side sealing film (in accordance with JIS K7210, 190 ° C., load 21). , Measured at 18 N. The same shall apply hereinafter) is higher than the melt flow rate of the ethylene-vinyl acetate copolymer of the light-receiving surface side sealing film, and the ethylene-vinyl acetate copolymer contained in the light-receiving surface side sealing film. The melt flow rate of coalescence is 2.0 to 10 g / 10 minutes, and the melt flow rate of the ethylene-vinyl acetate copolymer contained in the back side sealing film is more than 2.0 g / 10 minutes and not more than 30 g / 10 minutes, the light receiving side sealing film and the backside sealing film is viewed contains further a crosslinking agent, respectively, ethylene contained in the light receiving side sealing film - vinyl acetate copolymer vinyl acetate content of, 26.0～ This is achieved by a pair of sealing films for solar cells, which is 35% by mass .

  The wraparound is caused by the pressure applied to the end of the laminated body at the time of heating and pressurization, and the vicinity of the end of the laminated body is not pressurized in the vertical direction but is inclined inward. it is conceivable that. When the end is inclined and pressurized, as shown in the partial cross-sectional view of FIG. 4, the back surface side sealing film 13B pushes away the light receiving surface side sealing film 13A, and the back surface side sealing film 13B generates power. The light enters the light receiving surface side of the element 14.

As in the above configuration, by setting the EVA melt flow rate (MFR) of the back surface side sealing film higher than the MFR of EVA of the light receiving surface side sealing film, the light receiving surface side sealing film is relatively back side Since it becomes harder than the sealing film, it is possible to avoid a situation where the back surface side sealing film pushes away the light receiving surface side sealing film during heating and pressurization. Moreover, if the vinyl acetate content rate of the ethylene-vinyl acetate copolymer contained in the light-receiving surface side sealing film is in the above range, excellent adhesiveness and appropriate flexibility can be obtained, and workability becomes good.

Preferred embodiments of the pair of solar cell sealing films of the present invention are as follows.
(1) The difference between the melt flow rate of the ethylene-vinyl acetate copolymer of the back side sealing film and the melt flow rate of the ethylene-vinyl acetate copolymer of the light receiving side sealing film is 1 g / 10 min. That's it. Thereby, the difference in the relative hardness of the light-receiving surface side sealing film and the back surface side sealing film can be reliably obtained, and the wraparound can be reliably prevented .
(2 ) The vinyl acetate content of the ethylene-vinyl acetate copolymer contained in the back side sealing film is 20 to 35% by mass. According to this range, excellent adhesiveness and moderate flexibility can be obtained, and processability becomes good.
( 3 ) Each of the light-receiving surface side sealing film and the back surface side sealing film further contains a crosslinking agent. The power generation element can be tightly sealed, and airtightness, durability, and the like are improved.

  In addition, the object is to obtain a laminated body by laminating a light-receiving surface side transparent protective member, a light-receiving surface side sealing film, a power generation element, a back surface side sealing film, and a back surface side protective member in this order, In the method for manufacturing a solar cell module including a step of integrating by pressing and heating, the pair of solar cells is used as a pair of solar cell sealing films including the light-receiving surface side sealing film and the back surface side sealing film. This is achieved by a method for manufacturing a solar cell module, which uses a battery sealing film.

  Furthermore, in the solar cell module in which the light receiving surface side transparent protective member, the light receiving surface side sealing film, the power generation element, the back surface side sealing film, and the back surface side protective member are laminated in this order and bonded and integrated, A pair of solar cell sealing films composed of the light-receiving surface side sealing film and the back surface side sealing film is the above-described pair of solar cell sealing films.

  Further, in this solar cell module, the maximum length from the end of the power generation element of the back surface side sealing film penetrating between the power generation element and the light receiving surface side sealing film is less than 1 mm. It is advantageous to be.

  According to the pair of solar cell sealing films of the present invention, it is possible to prevent the back side colored sealing film from entering the light receiving surface of the power generation element during the manufacture of the solar cell module. Accordingly, it is possible to obtain a solar cell module in which the appearance characteristics and power generation efficiency are prevented from being lowered and the productivity is improved.

It is a schematic sectional drawing which shows an example of a solar cell module. It is a schematic sectional drawing which shows an example of a vacuum laminator. It is the top view which looked at the electric power generation element in the state where rounding occurred from the light-receiving surface side. It is a partial schematic sectional drawing explaining the cause of wraparound.

  Below, a pair of solar cell sealing film and solar cell module of the present invention will be described with reference to the drawings. FIG. 1 is a schematic cross-sectional view for explaining a pair of solar cell sealing films and a solar cell module of the present invention. As illustrated, the pair of solar cell sealing films of the present invention has a light receiving surface for sealing the power generating element 14 between the light receiving surface side transparent protective member 11 and the back surface side protective member (back cover) 12. It is a pair of two sealing films composed of the side sealing film 13A and the back side sealing film 13B. The light receiving surface side sealing film 13A seals between the power generating element 14 and the light receiving surface side transparent protective member 11 (transparent protective member on the light receiving surface side of the power generating element 14), and the back surface side sealing film 13B is the power generating element 14. And the back surface side protection member 12 (protection member opposite to the light receiving surface of the power generation element 14). A plurality of power generation elements 14 are usually provided and are electrically connected to each other by connection tabs 15 made of a conductive material such as copper foil. In the present invention, the light receiving surface side (front surface side) with respect to the power generating element is referred to as “light receiving surface side”, and the surface opposite to the light receiving surface of the power generating element is referred to as “back surface side”.

  The pair of solar cell sealing films according to the present invention, that is, the light-receiving surface side sealing film and the back surface side sealing film are mainly composed of an ethylene-vinyl acetate copolymer (EVA), and the back surface side sealing film As the EVA used for the above, the one whose melt flow rate (MFR) is higher than that of EVA used for the light-receiving surface side sealing film is used. This prevents the light-receiving surface side sealing film from being pushed into the back surface-side sealing film during the heating and pressurization described later, and the back surface side sealing melted between the light-receiving surface side sealing film and the power generation element. It is possible to prevent the film from entering.

  EVA MFR used for the light-receiving surface side sealing film is 0.1 to 30 g / 10 min, preferably 1.5 to 30 g / 10 min, particularly 2.0 to 10 g / 10 min, and further 2.0 to 6 It is preferably 0.0 g / 10 min. If it is lower than this range, cell cracking may occur during pressurization, and if it is higher than this range, the light-receiving surface side sealing film may become soft and pressurization may not be performed satisfactorily.

  EVA MFR used for the back side sealing film is more than 1.5 g / 10 min to 40 g / 10 min, particularly more than 2.0 g / 10 min to 30 g / 10 min, further 3.0 to 10 g / 10 Minutes are preferred. According to this range, it is possible to obtain a solar cell module that is well bonded and integrated without generating a power generation element crack during pressurization.

  Here, in this invention, the value of a melt flow rate (MFR) is measured based on the conditions of 190 degreeC and load 21.18N according to JISK7210. The MFR of the ethylene-vinyl acetate copolymer can be adjusted by various conditions such as composition, molecular weight, molecular weight distribution and the like.

  The difference between EVA MFR of the light-receiving surface side sealing film and EVA of the back surface side sealing film is 1 g / 10 min or more, preferably 1 to 35.5 g / 10 min, particularly 1 to 8 g / 10 min, It is preferable that it is 1-5 g / 10min. According to this range, a difference in relative hardness between the light-receiving surface side sealing film and the back surface side sealing film can be reliably obtained, and wraparound can be reliably prevented, and workability at the time of heating and pressurization can be prevented. Will also be good.

  Moreover, it is preferable that the vinyl acetate content rate of EVA used for a light-receiving surface side sealing film is 20-35 mass%, and especially 20-28 mass%, and the vinyl acetate content of EVA used for a back surface side sealing film is included. The rate is preferably 20 to 35% by mass, more preferably 23 to 33% by mass. If it is less than 20% by mass, the processability of the solar cell sealing film may be reduced, and if it exceeds 35% by mass, carboxylic acid, alcohol, etc. are generated and foamed at the interface with the member in contact with the sealing film. Is likely to occur. Further, according to this range, it is possible to efficiently prevent wraparound. The vinyl acetate content is measured according to the method described in JIS K6924.

  In addition to the ethylene-vinyl acetate copolymer, the light-receiving surface side sealing film and the back surface side sealing film are further polyvinyl acetal resins (for example, polyvinyl formal, polyvinyl butyral (PVB resin), modified PVB), and vinyl chloride resin. May be used as a secondary. In that case, PVB is particularly preferable. It is preferable that the ethylene-vinyl acetate copolymer is contained in each sealing film in an amount of 70% by mass or more, preferably 80 to 99% by mass with respect to the mass of each sealing film.

[Crosslinking agent]
In this invention, it is preferable that a light-receiving surface side sealing film and a back surface side sealing film contain the crosslinking agent for forming the crosslinked structure of an ethylene-vinyl acetate copolymer. As the crosslinking agent, an organic peroxide or a photopolymerization initiator is preferably used. Among these, it is preferable to use an organic peroxide because a sealing film with improved temperature dependency of adhesive strength, moisture resistance, and penetration resistance can be obtained.

  Any organic peroxide may 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, those having a decomposition temperature of 70 hours or more with a half-life of 10 hours are preferred.

  Examples of the organic peroxide include, from the viewpoint of resin processing temperature and storage stability, for example, benzoyl peroxide curing agent, tert-hexyl peroxypivalate, tert-butyl peroxypivalate, 3, 5, 5- Trimethylhexanoyl peroxide, di-n-octanoyl peroxide, lauroyl peroxide, stearoyl peroxide, 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate, succinic acid peroxide, 2,5-dimethyl-2,5-di (tert-butylperoxy) hexane, 2,5-dimethyl-2,5-di (2-ethylhexanoylperoxy) hexane, 1-cyclohexyl-1-methylethyl Peroxy-2-ethylhexanoate, tert-hexyl par Xyl-2-ethylhexanoate, 4-methylbenzoyl peroxide, tert-butylperoxy-2-ethylhexanoate, m-toluoyl + benzoyl peroxide, benzoyl peroxide, 1,1-bis (tert-butyl Peroxy) -2-methylcyclohexanate, 1,1-bis (tert-hexylperoxy) -3,3,5-trimethylcyclohexanate, 1,1-bis (tert-hexylperoxy) cyclohexanate 1,1-bis (tert-butylperoxy) -3,3,5-trimethylcyclohexane, 1,1-bis (tert-butylperoxy) cyclohexane, 2,2-bis (4,4-di-tert) -Butylperoxycyclohexyl) propane, 1,1-bis (tert-butyl) -Oxy) cyclododecane, tert-hexylperoxyisopropyl monocarbonate, tert-butylperoxymaleic acid, tert-butylperoxy-3,3,5-trimethylhexane, tert-butylperoxylaurate, 2,5- Dimethyl-2,5-di (methylbenzoylperoxy) hexane, tert-butylperoxyisopropyl monocarbonate, tert-butylperoxy-2-ethylhexyl monocarbonate, tert-hexylperoxybenzoate, 2,5-di-methyl -2,5-di (benzoylperoxy) hexane, and the like.

  As the benzoyl peroxide-based curing agent, any can be used as long as it decomposes at a temperature of 70 ° C. or higher to generate radicals, and those having a decomposition temperature of 50 hours or higher with a half-life of 10 hours are preferable, It can be appropriately selected in consideration of preparation conditions, film formation temperature, curing (bonding) temperature, heat resistance of the adherend, and storage stability. Usable benzoyl peroxide curing agents include, for example, benzoyl peroxide, 2,5-dimethylhexyl-2,5-bisperoxybenzoate, p-chlorobenzoyl peroxide, m-toluoyl peroxide, 2, Examples include 4-dichlorobenzoyl peroxide and t-butyl peroxybenzoate. The benzoyl peroxide curing agent may be used alone or in combination of two or more.

  As organic peroxides, in particular, 2,5-dimethyl-2,5-di (tert-butylperoxy) hexane, 1,1-bis (tert-hexylperoxy) -3,3,5-trimethylcyclohexane preferable. Thereby, the sealing film for solar cells which has the outstanding insulating property is obtained.

  The content of the organic peroxide is preferably 0.1 to 5 parts by mass, more preferably 0.2 to 3 parts by mass with respect to 100 parts by mass of the ethylene-vinyl acetate copolymer. If the content of the organic peroxide is small, the insulating properties of the resulting sealing film may be lowered, and if it is increased, the compatibility with the copolymer may be deteriorated.

  As the photopolymerization initiator, any known photopolymerization initiator can be used, but a photopolymerization initiator having good storage stability after blending is desirable. Examples of such a photopolymerization initiator include 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-hydroxycyclohexyl phenyl ketone, and 2-methyl-1- (4- (methylthio) phenyl). Acetophenones such as 2-morpholinopropane-1, benzoins such as benzyldimethylketal, benzophenones such as benzophenone, 4-phenylbenzophenone and hydroxybenzophenone, thioxanthones such as isopropylthioxanthone and 2-4-diethylthioxanthone, As other special ones, methylphenylglyoxylate can be used. Particularly preferably, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-hydroxycyclohexyl phenyl ketone, 2-methyl-1- (4- (methylthio) phenyl) -2-morpholinopropane-1, Examples include benzophenone. These photopolymerization initiators may contain one or two or more kinds of known and commonly used photopolymerization accelerators such as benzoic acid-based or tertiary amine-based compounds such as 4-dimethylaminobenzoic acid as required. Can be mixed and used. Moreover, it can be used individually by 1 type of only a photoinitiator, or 2 or more types of mixture.

  The content of the photopolymerization initiator is preferably 0.1 to 5 parts by mass with respect to 100 parts by mass of the ethylene-vinyl acetate copolymer.

[Crosslinking aid]
The light-receiving surface side sealing film and the back surface side sealing film may further contain a crosslinking aid, if necessary. The said crosslinking adjuvant can improve the gel fraction of an ethylene-vinyl acetate copolymer, and can improve the adhesiveness and durability of a sealing film.

  The content of the crosslinking aid is generally 10 parts by mass or less, preferably 0.1 to 5 parts by mass, more preferably 0.1 to 2.5 parts by mass with respect to 100 parts by mass of the ethylene-vinyl acetate copolymer. Used in the department. Thereby, the sealing film excellent in adhesiveness is obtained.

  Examples of the crosslinking aid (compound having a radical polymerizable group as a functional group) include trifunctional crosslinking aids such as triallyl cyanurate and triallyl isocyanurate, and (meth) acrylic esters (eg, NK ester) ) Monofunctional or bifunctional crosslinking aids. Of these, triallyl cyanurate and triallyl isocyanurate are preferable, and triallyl isocyanurate is particularly preferable.

[Adhesion improver]
It is preferable that the light-receiving surface side sealing film and the back surface side sealing film have an excellent adhesive force in consideration of the sealing performance inside the solar cell module. Therefore, an adhesion improver may be further included. 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. Of these, γ-methacryloxypropyltrimethoxysilane is particularly preferred.

  The content of the silane coupling agent is 5 parts by mass or less, preferably 0.1 to 2 parts by mass with respect to 100 parts by mass of the ethylene-vinyl acetate copolymer.

[Colorant]
The back side sealing film used in the present invention contains a colorant. The colorant is not particularly limited. For example, white colorant such as titanium white (titanium dioxide) or calcium carbonate; blue colorant such as ultramarine; black colorant such as carbon black; milky white due to glass beads and light diffusing agent Coloring agents and the like can be used. Preferably, a white colorant based on titanium white can be used.

  The colorant is preferably 2 to 10 parts by mass, more preferably 100 parts by mass with respect to 100 parts by mass of the ethylene-vinyl acetate copolymer contained in the back side sealing film (also referred to herein as the back side colored sealing film). It is preferable that 3-6 mass parts is contained.

[Others]
In order to improve or adjust various physical properties of the film (mechanical strength, optical characteristics, heat resistance, light resistance, crosslinking speed, etc.), the light-receiving surface side sealing film and the back surface side sealing film are used as necessary. Various additives such as a plasticizer, an acryloxy group-containing compound, a methacryloxy group-containing compound and / or an epoxy group-containing compound, an ultraviolet absorber, a light stabilizer and an anti-aging agent may be included.

  The light-receiving surface side sealing film and the back surface side sealing film may be formed according to a known method. For example, the composition containing each of the above-described components can be produced by a method of obtaining a sheet-like material by molding by ordinary extrusion molding, calendar molding (calendering) or the like. 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. The heating temperature during film formation is preferably a temperature at which the crosslinking agent does not react or hardly reacts. For example, it is preferably 50 to 90 ° C, particularly 40 to 80 ° C. The thickness of the light-receiving surface side sealing film and the back surface side sealing film is generally 0.05 to 2 mm, particularly 0.4 to 0.7 mm.

[Light-receiving side transparent protective member]
The light-receiving surface side transparent protective member used for the solar cell module of the present invention can usually use a glass substrate such as silicate glass. The thickness of the light-receiving surface side transparent protective member is generally 0.1 to 10 mm, and preferably 0.3 to 5 mm. In general, the light-receiving surface side transparent protective member may be chemically or thermally strengthened.

[Back side protection member]
The back side protective member used in the present invention is preferably a plastic film such as polyethylene terephthalate (PET) or polyamide. In consideration of heat resistance and heat-and-moisture resistance, a film obtained by laminating a fluorinated polyethylene film, particularly a fluorinated polyethylene film / Al / fluorinated polyethylene film in this order, polyvinyl fluoride (trade name: Tedlar) / PET / A film in which polyvinyl fluoride is laminated in this order may also be used.

[Power generation element]
The power generating element used in the solar cell module performs photoelectric conversion, and a conventionally known semiconductor substrate is used. As the semiconductor substrate, an optical semiconductor element composed of single crystal, polycrystal, or amorphous is used. Specifically, amorphous silicon a-Si, hydrogenated amorphous silicon a-Si: H, hydrogenated amorphous silicon carbide a-SiC: H, amorphous silicon nitride, etc. Amorphous or microcrystalline amorphous silicon semiconductors composed of alloys with other elements such as carbon, germanium, tin, etc. are pin-type, nip-type, ni-type, pn-type, MIS-type, heterojunction-type, homojunction A semiconductor layer configured as a mold, a Schottky barrier type, or a combination of these is used. In addition, the optical semiconductor layer may be CdS-based, GaAs-based, InP-based, or the like.

  What is necessary is just to perform according to a conventionally well-known method when incorporating a power generation element in a solar cell module. For example, an inner lead such as copper foil applied by solder plating is connected to the electrode of the power generation element, and the power generation element is connected in series and parallel with the inner lead so that a predetermined electrical output can be taken out from the solar cell module. To do.

[Method for manufacturing solar cell module]
As shown in FIG. 1, the manufacturing method of the solar cell module of the present invention includes a light receiving surface side transparent protective member 11, a light receiving surface side sealing film 13A, a power generation element 14, a back surface side colored sealing film 13B, and a back surface side protective member. The laminate 10 is obtained by laminating 12 in this order, and the laminate 10 is integrated by pressurizing and heating. Hereinafter, the integrated process of the laminated body in the manufacturing method of the solar cell module of this invention is demonstrated.

  The method for pressurizing and heating the laminate is not particularly limited. For example, it is preferable to use a vacuum laminator having an inflatable diaphragm, particularly a vacuum laminator of the double vacuum chamber system shown in FIG.

  A vacuum laminator 100 shown in FIG. 2 includes an upper chamber 102 having a diaphragm 103 and a lower chamber 101 having a mounting table 105 for mounting the stacked body 10. In the vacuum laminator 100, the laminated body 10 is pressurized by the diaphragm 103 after evacuating the upper chamber 102 and the lower chamber 101. The evacuation in the upper chamber 102 and the lower chamber 101 is performed by dividing the lower chamber vacuum pump 107 connected to the lower chamber exhaust port 106 and the upper chamber vacuum pump 109 connected to the upper chamber exhaust port 108. Is done.

  In order to pressurize the laminated body 10 using such a vacuum laminator, first, the light receiving surface side transparent protective member 11, the light receiving surface side sealing film 13 </ b> A are placed on the mounting table 105 provided in the lower chamber 101. The stacked body 10 obtained by stacking the power generation element 14, the back surface side sealing film 13B, and the back surface side protection member 12 in this order is placed so that the light receiving surface side transparent protection member 11 is in contact with the mounting table 105. . Next, after the upper chamber 102 and the lower chamber 101 are evacuated and vacuumed by the upper chamber vacuum pump 109 and the lower chamber vacuum pump 107, respectively, the inside of the upper chamber 102 is preferably set to a pressure higher than the atmosphere. Thereby, the uppermost surface of the laminated body 10 is pressed by the diaphragm 103, and the laminated body 10 is pressurized.

  In order to make each of the upper chamber 102 and the lower chamber 101 vacuum, it is preferable that the upper chamber 102 and the lower chamber 101 are first depressurized to 50 to 150 Pa, particularly 50 to 100 Pa, respectively. The vacuum time is, for example, 0.1 to 5 minutes. Then, the laminated body is uniformly pressed by the diaphragm 103 by setting the inside of the upper chamber to 40 to 110 kPa, particularly 60 to 105 kPa.

It is preferable to adjust the degree of expansion of the diaphragm so that the laminate is pressurized at a pressure of 1.0 × 10 ³ Pa to 5.0 × 10 ⁷ Pa, particularly 60 to 105 kPa. The pressing time is, for example, 5 to 15 minutes.

  In the method of the present invention, heating is performed together with pressurization. As a heating method, the entire vacuum laminator 100 shown in FIG. 2 is heated in a high-temperature environment such as an oven, and a heating medium such as a heating plate is introduced into the lower chamber 101 of the vacuum laminator 100 shown in FIG. The method of heating the body 10 etc. are mentioned. In the latter method, for example, a heating plate is used as the mounting table 105, a heating plate is arranged on the upper side and / or lower side of the mounting table 105, or a heating plate is arranged on the upper side and / or lower side of the stacked body. It is done by doing.

  Among these heating methods, it is preferable to heat the laminated body from the light receiving surface side transparent protective member 11 side using a heating plate as a mounting table. As a result, heat transfer to the light-receiving surface side sealing film is performed more quickly, the adhesion between the light-receiving surface side sealing film and the power generation element is improved, and the back surface side sealing film is more reliably avoided. be able to.

  The laminate is preferably heated to a temperature of 80 to 150 ° C, particularly 90 to 145 ° C. The heating time may be 10 minutes to 1 hour. Further, it is more preferable that the laminate is preheated at a temperature of 80 to 120 ° C., then heated at a temperature of 100 to 150 ° C. (particularly around 130 ° C.), and heated stepwise.

  It is preferable to pressurize and heat the laminated body by heating the laminated body up to the above temperature, evacuating the vacuum laminator, and then expanding the diaphragm.

  In the present invention, since the EVA of the back surface side sealing film is higher than the EVA MFR of the light receiving surface side sealing film, the light receiving surface side sealing film is relative to the back surface side sealing film. Even if the applied pressure is concentrated on the end of the laminate in the heating and pressurizing process, the back side sealing film becomes the light receiving side sealing film depending on the hardness of the light receiving side sealing film. Pushing is avoided and wraparound is prevented. In the manufactured solar cell module, the wraparound length of the back surface side sealing film, that is, from the end of the power generating element of the back surface side sealing film that has entered between the power generating element and the light receiving surface side sealing film If the maximum length is less than 1 mm, preferably 0.7 mm or less, a solar cell module that hardly affects the appearance and power generation efficiency of the solar cell module can be obtained.

  Hereinafter, the present invention will be described in detail with reference to examples.

[Examples and Reference Examples 1 to 28, Comparative Examples 1 to 19]
1. Preparation of light-receiving surface side sealing film Using the ethylene-vinyl acetate copolymers shown in Tables 1 to 3, materials having the following composition were supplied to a roll mill and kneaded at 70 ° C. The sealing film composition thus obtained was calendered at 70 ° C. to prepare a light-receiving surface side sealing film (thickness 0.6 mm).

(Combination)
-100 parts by mass of ethylene-vinyl acetate copolymer-Crosslinking agent (2,5-dimethyl-2,5-di (t-butylperoxy) hexane)
(Perhexa 25B: manufactured by NOF Corporation) 1.5 parts by mass / crosslinking aid (triallyl isocyanurate)
(TAIC: manufactured by Nippon Kasei) 1.5 parts by mass / Silane coupling agent (γ-methacryloxypropyltrimethoxysilane)
(KBM503: manufactured by Shin-Etsu Chemical) 0.3 parts by mass

2. Production of Back Side Sealing Film Using the ethylene-vinyl acetate copolymers shown in Tables 1 to 3, materials having the following composition were supplied to a roll mill and kneaded at 70 ° C. The sealing film composition thus obtained was calendered at 70 ° C. to prepare back side sealing films (thickness 0.6 mm).

(Combination)
-100 parts by mass of ethylene-vinyl acetate copolymer-Crosslinking agent (2,5-dimethyl-2,5-di (t-butylperoxy) hexane)
(Perhexa 25B: manufactured by NOF Corporation) 1.5 parts by mass / crosslinking aid (triallyl isocyanurate)
(TAIC: manufactured by Nippon Kasei) 1.5 parts by mass / Silane coupling agent (γ-methacryloxypropyltrimethoxysilane)
(KBM503: manufactured by Shin-Etsu Chemical Co., Ltd.) 0.3 parts by mass / colorant (titanium dioxide) 5.0 parts by mass

3. Production of solar cell module Light-receiving surface side transparent protective member (white plate tempered glass (with emboss), 230 mm × 230 mm × 3.2 mm) / light-receiving surface side sealing film (230 mm × 230 mm) / power generation element (single crystal silicon cell: 125 mm × 125 mm, thickness: 220 μm) / back side sealing film (230 mm × 230 mm) / back side protection member (TPT (Tedlar / PET / Tedlar: Model No. 2442), thickness: 350 μm) manufactured by Isovolta After the lamination, this laminated body was bonded and integrated at 145 ° C. with a vacuum time of 5 minutes, a pressure of 0.1 MPa, and a pressing time of 15 minutes using a double vacuum chamber type vacuum laminator equipped with a diaphragm to produce a solar cell module. did.

<Evaluation method>
-Measurement of wraparound amount About the produced solar cell module, the wraparound amount on the light-receiving surface of the power generation element of the back surface side sealing film was measured. The wraparound amount was measured by measuring the maximum length (mm) from the end of the power generation element of the back side sealing film where the wraparound occurred on a scale. Less than 1 mm was accepted. The results are shown in Tables 1-3.

<Evaluation results>
As shown in Tables 1 to 3, when the EVA MFR of the back surface side sealing film is higher than the EVA MFR of the light receiving surface side sealing film, the amount of wraparound is reduced compared to the other comparative examples. It was recognized that As described above, according to the pair of solar cell sealing films satisfying the above-described conditions, it is possible to obtain a solar cell module in which the back surface side sealing film is prevented from wrapping around and deterioration in appearance and power generation efficiency is prevented. Admitted.

  According to the pair of solar cell sealing films according to the present invention, it is possible to prevent the back surface side sealing film from wrapping around, and to obtain a solar cell module in which deterioration in appearance characteristics and power generation efficiency are prevented. it can.

11 light-receiving surface side transparent protective member 12 back surface side protective member 13A light-receiving surface side sealing film 13B back surface side sealing film 14 power generation element 15 connection tab

Claims (6)

A pair of solar cell sealing films for sealing a power generating element disposed between a light-receiving surface side transparent protective member and a back surface-side protective member from the light-receiving surface side and the back surface side,
The light-receiving surface side sealing film disposed between the light-receiving surface-side transparent protective member and the power generation element includes an ethylene-vinyl acetate copolymer,
The back side sealing film disposed between the back side protection member and the power generation element includes an ethylene-vinyl acetate copolymer and a colorant,
The ethylene-vinyl acetate copolymer melt flow rate (measured at 190 ° C. under a load of 21.18 N according to JIS K7210; the same applies hereinafter) of the back side sealing film is the ethylene-acetic acid of the light receiving side sealing film. Higher than the melt flow rate of the vinyl copolymer,
The melt flow rate of the ethylene-vinyl acetate copolymer contained in the light-receiving surface side sealing film is 2.0 to 10 g / 10 minutes,
The melt flow rate of the ethylene-vinyl acetate copolymer contained in the back side sealing film is more than 2.0 g / 10 minutes and not more than 30 g / 10 minutes,
The light receiving side sealing film and the backside sealing film is viewed contains further a crosslinking agent, respectively,
A pair of solar cell sealing films, wherein the ethylene-vinyl acetate copolymer contained in the light-receiving surface side sealing film has a vinyl acetate content of 26.0 to 35% by mass .   The difference between the melt flow rate of the ethylene-vinyl acetate copolymer of the back surface side sealing film and the melt flow rate of the ethylene-vinyl acetate copolymer of the light receiving surface side sealing film is 1 g / 10 min or more. The pair of solar cell sealing films according to claim 1. The pair of solar cells for sealing according to claim 1 or 2 , wherein the ethylene-vinyl acetate copolymer contained in the back side sealing film has a vinyl acetate content of 20 to 35 mass%. film. A laminated body is obtained by laminating the light-receiving surface side transparent protective member, the light-receiving surface side sealing film, the power generation element, the back surface side sealing film, and the back surface side protective member in this order, and pressurizing and heating the laminated body In the manufacturing method of the solar cell module including the process of integrating by
The pair of solar cell sealing films according to any one of claims 1 to 3 , wherein the pair of solar cell sealing films including the light-receiving surface side sealing film and the back surface side sealing film is used. The manufacturing method of the solar cell module characterized by these. In the solar cell module formed by laminating the light receiving surface side transparent protective member, the light receiving surface side sealing film, the power generation element, the back surface side sealing film, and the back surface side protective member in this order, and bonding and integrating them,
The pair of the solar cell sealing film made of the light receiving side sealing film and the backside sealing film is a sealing film a pair of solar cell according to any one of claims 1 to 3 A featured solar cell module.   The maximum length from the end portion of the power generation element of the back surface side sealing film penetrating between the power generation element and the light receiving surface side sealing film is less than 1 mm. 5. The solar cell module according to 5.

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