WO2013073637A1

WO2013073637A1 - Solar cell module

Info

Publication number: WO2013073637A1
Application number: PCT/JP2012/079701
Authority: WO
Inventors: 達章坂野
Original assignee: 京セラ株式会社
Priority date: 2011-11-15
Filing date: 2012-11-15
Publication date: 2013-05-23
Also published as: JP5409966B2; JPWO2013073637A1

Abstract

In order to provide s solar cell module which has further improved durability by reducing the formation of rust at least on a wiring member or an electrode arranged within the solar cell module without lowering the power generation performance, the solar cell module is provided with: a solar cell (for example, a solar cell element (10)) which has a first surface that serves as a light-receiving surface and a second surface that is on the reverse side of the first surface; a light-transmitting first protective member (11) which is arranged on the first surface side of the solar cell; a second protective member (14) which is arranged on the second surface side of the solar cell; a first sealing member (12) which is arranged between the first surface of the solar cell and the first protective member (11); and a second sealing member (13) which is arranged between the second surface of the solar cell and the second protective member (14). The first sealing member (12) and/or the second sealing member (13) contains an ethylene-vinyl acetate copolymer and an organic compound that has a functional group containing nitrogen and functions as an acid acceptor.

Description

Solar cell module

The present invention relates to a solar cell module using a sealing material mainly composed of an ethylene vinyl acetate copolymer (hereinafter referred to as EVA).

In recent years, solar cell modules that directly convert sunlight into electrical energy have been widely used around the world in terms of effective use of resources and countermeasures for environmental problems, and further development of this solar cell module has been promoted. Yes.

Generally, a solar cell module has a sealing material disposed on the light receiving surface side and a sealing material disposed on the back surface side between the translucent light receiving surface side protective material and the back surface side protective material (back cover). It is set as the structure which sealed the some solar cell element pinched | interposed by.

As the sealing material used on each of the light-receiving surface side and the back surface side, EVA which is inexpensive and has high transparency and adhesiveness is preferably used (see, for example, Japanese Patent No. 3473605).

When the solar cell module is used over a long period of time in an environment of high temperature and high humidity or exposed to wind and rain, moisture or water may enter the solar cell module. For example, when a sealing material made of EVA is used, since EVA contains vinyl acetate as its component, EVA tends to hydrolyze over time due to infiltration of moisture or water at a high temperature to generate acetic acid. . And it has become clear that the acetic acid generated in this way contacts at least the wiring member or the electrode of the solar cell element arranged inside the solar cell module and promotes the generation of rust in these members. .

Therefore, it has been proposed to use an EVA film containing 0.5% by mass or less of an acid acceptor of an inorganic powder having an average particle size of 5 μm or less as a transparent film used as a sealing material for a solar cell module (for example, (See JP 2005-29588 A). According to the EVA film containing this acid acceptor, it is possible to suppress the generation of acetic acid and improve the durability of the solar cell module.

As described above, in order to reduce the occurrence of rust in at least the wiring members or electrodes arranged inside the solar cell module and improve the durability of the solar cell module, the seals used on the light receiving surface side and the back surface side are used. An effective means is to add an acid acceptor to the stopper.

However, the addition of an acid acceptor for inorganic powders may lead to a decrease in the transparency of the encapsulant. Therefore, simply adding an acid acceptor to improve durability will improve the power generation performance of the solar cell module. There is a risk of lowering.

Therefore, the present invention aims to provide a solar cell module with further improved durability by reducing the occurrence of rust in at least wiring members or electrodes inside the solar cell module without degrading the power generation performance. One.

The solar cell module according to the present invention is disposed on the first surface side of the solar cell, the solar cell having a first surface that is a light receiving surface and a second surface that is located on the opposite side of the first surface. A translucent first protective material, a second protective material disposed on the second surface side of the solar cell, and between the first surface of the solar cell and the first protective material. A first sealing material disposed; a second sealing material disposed between the second surface of the solar cell and the second protective material; and the first sealing material. At least one of the material and the second sealing material includes EVA and an organic compound having a functional group having nitrogen and functioning as an acid acceptor.

According to the solar cell module having the above configuration, at least one of the first sealing material and the second sealing material contains EVA and an organic compound that functions as an acid acceptor. It is possible to reduce the generation of rust in at least wiring members or electrodes arranged inside the solar cell module without maintaining the transparency of the material and reducing the power generation performance, and high power generation over a long period of time. It is possible to provide a solar cell module that can exhibit performance and has excellent durability.

It is a figure which shows typically one Embodiment of the solar cell module which concerns on this invention, and is the top view seen from the light-receiving surface side. FIG. 2 is a diagram schematically showing one embodiment of a solar cell module according to the present invention, and is a cross-sectional view taken along the line A-A ′ in FIG. 1.

Hereinafter, an embodiment of a solar cell module according to the present invention will be described in detail with reference to the drawings. In the drawings, similar constituent elements are denoted by the same reference numerals, and redundant description is omitted. Further, since the drawings are schematically shown, the sizes and positional relationships of the constituent elements in each drawing can be appropriately changed.

As shown in FIG. 1 and FIG. 2, the solar cell module 20 has a light receiving surface 20a on which light is irradiated and a back surface 20b located on the opposite side to the light receiving surface 20a. Further, the solar cell element 10 which is a solar cell in which electrodes (front surface electrode 16, back surface electrode 17) are arranged on the main surfaces facing the light receiving surface 20a and the back surface 20b of the solar cell module 20, and the solar cell element The light-transmitting first protective material 11 disposed on the first surface 10a side which is the light receiving surface (front surface) of the solar cell element 10 and the first surface 10a of the solar cell element 10 are located on the opposite side. The second protective material 14 disposed on the second surface 10b side, which is the back surface of the solar cell element 10, and the first sealing material disposed between the first surface 10a of the solar cell element 10 and the first protective material 11 12, and a second sealing material 13 disposed between the second surface 10 b of the solar cell element 10 and the second protective material 14.

And at least one of the first sealing material 12 and the second sealing material 13 contains EVA and an organic compound that has a functional group having nitrogen and functions as an acid acceptor. Hereinafter, an organic compound having a functional group having nitrogen is referred to as an “organic nitrogen compound”. For example, at least one of the first sealing material 12 and the second sealing material 13 may be made of EVA containing an organic nitrogen compound. In addition, at least one of the first sealing material 12 and the second sealing material 13 includes a first region including an organic nitrogen compound provided in the vicinity of a portion where the wiring member or the electrode is disposed, and other regions. And a second region made of EVA.

The solar cell may be a single solar cell element 10 or, as shown in FIGS. 1 and 2, a plurality of solar cell elements 10 are electrically connected in series or series-parallel to each other via a wiring member 15. It may be a solar cell element string or the like. In the solar cell module 20, the plurality of solar cell elements 10 are disposed on the light receiving surface side of one adjacent solar cell element 10 and on the back surface side of the other solar cell element 10. The electrodes are electrically connected via the wiring member 15.

In addition, the solar cell module 20 may include a terminal box (not shown) for taking out the electric power generated by the solar cell element 10 outside the second protective material 14.

By including EVA in at least one of the first sealing material 12 and the second sealing material 13, at least one of the first sealing material 12 and the second sealing material 13 and the first protective material 11. Alternatively, the adhesion between the second protective material 14 can be improved. And the simple sealing which can reduce permeation | transmission of the water | moisture content etc. to the inside of the solar cell module 20 is implement | achieved.

In this embodiment, at least one of the first sealing material 12 and the second sealing material 13 absorbs an acid such as acetic acid or has a high function of neutralizing an acid such as acetic acid. Organic nitrogen compounds that function as

This makes it easier for organic nitrogen compounds to be uniformly dispersed in EVA, which is also an organic substance, as compared with conventional acid acceptors made of inorganic powders.

Furthermore, even if the content of the organic nitrogen compound of EVA is increased, the transparency of the sealing material can be ensured.

From these things, it was excellent in the durability etc. by which generation | occurrence | production of the rust was reduced at least in the wiring member 15 or electrode arrange | positioned inside the solar cell module 20, without reducing the electric power generation performance of the solar cell module 20 The solar cell module 20 can be provided.

Specifically, when the first sealing material 12 disposed on the first surface 10a side of the solar cell element 10 includes EVA and an organic nitrogen compound, the amount is 0.01 with respect to 100 parts by mass of EVA. By containing the organic nitrogen compound of ˜0.5 parts by mass, the transparency of the first sealing material 12 can be ensured, and it is arranged inside the solar cell module 20 without deteriorating the power generation performance. Thus, it is possible to provide the solar cell module 20 having excellent durability and the like in which the generation of rust is reduced at least in the wiring member 15 or the electrode.

In particular, in the first sealing material 12, the first sealing material disposed on the first surface 10a side by containing 0.075 to 0.3 parts by mass of an organic nitrogen compound with respect to 100 parts by mass of EVA. While ensuring high transparency of the material 12, the generation of rust can be reduced at least in the wiring member 15 or the electrode disposed inside the solar cell module 20, and the power generation performance can be further improved.

Moreover, when the 2nd sealing material 13 arrange | positioned at the 2nd surface 10b side of the solar cell element 10 contains EVA and an organic nitrogen compound, it is 0.01 mass part or more with respect to 100 mass parts EVA. By including the organic nitrogen compound, it is possible to provide the solar cell module 20 in which the occurrence of rust is reduced at least in the wiring member 15 or the electrode disposed inside the solar cell module 20 without reducing the power generation performance.

In particular, in the second sealing material 13, at least wiring disposed inside the solar cell module 20 is contained by including 0.15 to 1.0 part by mass of an organic nitrogen compound with respect to 100 parts by mass of EVA. The occurrence of rust in the member 15 or the electrode can be further suitably reduced.

Moreover, EVA and an organic nitrogen compound may be included in both the first sealing material 12 and the second sealing material 13. In this case, in particular, the content of the organic nitrogen compound with respect to EVA in the second sealing material 13 is preferably larger than the content of the organic nitrogen compound with respect to EVA in the first sealing material 12. This is because moisture tends to enter from the side of the second sealing material 13 disposed on the second surface 10b side that is generally protected by the second protective material 14 that is thinner than the first protective member 11.

Examples of organic nitrogen compounds include primary amines, amines composed of secondary amines and tertiary amines, or oximes having a structure represented by imines, amides, imides, and> C = N? OH. Etc. As other organic nitrogen compounds, compounds having a urea bond typified by urea, monocyclic, heterocyclic compounds or derivatives thereof having a nitrogen atom typified by pyridine, imidazole and carbazole, or the like, or There may be mentioned quaternary ammonium salts such as tetramethylammonium hydroxide.

Primary amines include methyl groups such as methylamine, ethylamine and propylamine, alkyl groups such as methyl, ethyl and propyl groups,
Or an alkenyl group such as an ethenyl group and a propenyl group,
Or a saturated or unsaturated aliphatic amine having 1 to 18 carbon atoms having an alkynyl group such as an ethynyl group or a propynyl group,
Or a saturated or unsaturated aliphatic amine having 1 to 18 carbon atoms having a plurality of amino groups such as methylenediamine and ethylenediamine,
Or a saturated, unsaturated aliphatic amine having 1 to 18 carbon atoms having a substituent containing a hydroxyl group such as trishydroxymethylaminomethane and ethanolamine,
Or amino acids containing glycine, alanine and histidine,
Or monosaccharides such as glucose and cellulose, amine derivatives of polysaccharides,
Or aromatic amines, such as aniline and toluidine, etc. are mentioned.

Examples of secondary amines include saturated aliphatic secondary amines or unsaturated aliphatic secondary amines having 1 to 18 carbon atoms such as diethylamine, N, N′-dimethylethylenediamine, and diethanolamine.
Or aromatic secondary amines, such as diphenylamine, etc. are mentioned.

Tertiary amines include saturated aliphatic tertiary amines or unsaturated aliphatic tertiary amines having 1 to 18 carbon atoms such as triethylamine, N, N, N ′, N′-tetraethylethylenediamine,
Or aromatic tertiary amines, such as a triphenylamine, etc. are mentioned.

Examples of imines include cyclic secondary amines such as ethyleneimine and piperazine represented by the general formula (CH ₂ ) _n NH,
Examples thereof include N-methylethaneimine and propane-2-imine having a C═N double bond.

Examples of amides or imides include lauric acid, which is a saturated fatty acid having 4 to 30 carbon atoms,
Or linoleic acid or linolenic acid which is an unsaturated fatty acid,
Alternatively, amides or imides synthesized from aromatic benzoic acid, salicylic acid, phthalic acid, or the like can be given.

Further, examples of the organic nitrogen compound include condensates, polymers, and copolymers of the above-described substances.

The second sealing material 13 preferably further contains a colorant. For example, by using a white colorant, by reflecting light at the interface between the first sealing material 12 and the second sealing material 13 inside the solar cell module 20, or by irregular reflection of light by the colorant, etc. Light incident between the solar cell elements 10 or light that has passed through the solar cell element 10 can be diffusely reflected and incident on the solar cell element 10 again. Thereby, since the utilization efficiency of the light which injected into the solar cell module 20 increases, the power generation performance of the solar cell module 20 can be improved. Moreover, since the 2nd sealing material 13 which can be confirmed from the light-receiving surface side of the solar cell module 20 becomes the same color as the solar cell element 10 by using a dark colorant, the appearance of the solar cell module 20 is aesthetically pleasing. Can be improved.

As colorants, white colorants such as titanium oxide, calcium carbonate, zinc white (zinc oxide), lead white (basic lead carbonate), lithopone, barite, precipitated barium sulfate or gypsum,
Or blue colorants such as ultramarine,
Or a black colorant such as carbon black,
Alternatively, milky white colorants such as glass beads and light diffusing agents can be used. Among these, it is particularly preferable to use a white colorant in terms of improving power generation performance.

The colorant is preferably contained in 2 to 10 parts by mass, more preferably 3 to 6 parts by mass with respect to 100 parts by mass of EVA contained in the second sealing material 13. The average particle diameter of the colorant is preferably 0.01 to 10 μm, particularly preferably 0.1 to 5 μm. Thereby, the utilization efficiency of incident light can be increased. The average particle diameter of the colorant is obtained by observing the cross section of the second sealing material 13 at a magnification of about 1,000,000 using a transmission electron microscope, thereby obtaining a projected area circle equivalent diameter of at least 100 colorants. The average value.

It is preferable that the second sealing material 13 further contains a lubricant. Thereby, the adhesiveness of a sealing material improves and it becomes possible to reduce that a water | moisture content etc. permeate into the solar cell module 20 inside.

A phosphite compound is preferably used as the lubricant. Examples of the phosphite compound include alkyl phosphites such as decyl phosphite, alkyl or aryl acid phosphates such as decyl acid phosphate and phenyl acid phosphate,
Examples include trialkyl or triaryl phosphates such as trihexyl phosphate and tricresyl phosphate, or zinc dithiophosphate.

The content of the lubricant is preferably 0.01 to 5.0 parts by mass, particularly 0.1 to 0.4 parts by mass with respect to 100 parts by mass of EVA contained in the second sealing material 13.

At least one of the first sealing material 12 and the second sealing material 13 contains EVA. The content of vinyl acetate in EVA is preferably 20 to 35 parts by mass, more preferably 22 to 30 parts by mass, and particularly preferably 24 to 28 parts by mass with respect to 100 parts by mass of EVA. By setting the content of vinyl acetate within the above range, it is possible to ensure the transparency of the encapsulant obtained when crosslinked and cured at a high temperature.

It is preferable that at least one of the first sealing material 12 and the second sealing material 13 further includes a crosslinking agent. Thereby, EVA can be cross-linked and cured, and durability can be improved.

As the crosslinking agent, it is preferable to use an organic peroxide because a sealing material with improved temperature dependency of adhesive strength, transparency, moisture resistance and penetration resistance can be obtained.

Organic peroxides can be used as long as they decompose at a temperature of 100 ° C. or higher and generate free 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 and storage stability of the adherend. In particular, the one having a decomposition temperature of 70 ° C. or more with a half-life of 10 hours is preferable.

Examples of the organic peroxide include 2,5-dimethylhexane-2,5-dihydroperoxide, 2,5-dimethyl-2,5-di (tert) from the viewpoint of the processing temperature and storage stability of the resin. -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-butylcumyl peroxide, α, α'-bis (tert-butylperoxyisopropyl) benzene, α, α'-bis (tert-butylperoxy) diisopropyl Rubenzene, n-butyl-4,4-bis (tert-butylperoxy) butane, 2,2-bis (tert-butylperoxy) butane, 1,1-bis (tert-butylperoxy) cyclohexane, 1, Preferable examples include 1-bis (tert-butylperoxy) 3,3,5-trimethylcyclohexane, tert-butylperoxybenzoate, benzoyl peroxide and the like. These may be used individually by 1 type, and 2 or more types may be mixed and used for them.

The content of the crosslinking agent in at least one of the first sealing material 12 and the second sealing material 13 is preferably 0.1 to 5 parts by mass, more preferably 0.5 to 100 parts by mass with respect to 100 parts by mass of EVA. Suppose that it is 2 mass parts. By making content of a crosslinking agent into the said range, compatibility with a copolymer can be improved, maintaining the transparency of a sealing material.

At least one of the first sealing material 12 and the second sealing material 13 may further contain a crosslinking aid as necessary. The crosslinking aid can improve the gel fraction of EVA and improve durability.

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 (for example, NK ester). And monofunctional or bifunctional crosslinking aids. Of these, triallyl cyanurate or triallyl isocyanurate is particularly preferred, and triallyl isocyanurate is particularly preferred.

The content of the crosslinking assistant in at least one of the first sealing material 12 and the second sealing material 13 is 0.1 to 3 parts by mass, particularly 0.1 to 2.5 parts by mass with respect to 100 parts by mass EVA. It is preferable to set it as a mass part.

It is preferable that at least one of the first sealing material 12 and the second sealing material 13 has an excellent adhesive force in view of the sealing performance inside the solar cell module 20. Therefore, at least one of the first sealing material 12 and the second sealing material 13 may further include an adhesion improver.

シラン A silane coupling agent can be used as an adhesion improver. This makes it possible to form a sealing material having an excellent adhesive force. Examples of silane coupling agents include γ-chloropropylmethoxysilane, vinylethoxysilane, vinyltris (β-methoxyethoxy) silane, γ-methacryloxypropyltrimethoxysilane, vinyltriacetoxysilane, γ-glycidoxypropyltrimethoxysilane, 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 can be used alone or in combination of two or more. Of these, γ-methacryloxypropyltrimethoxysilane can be particularly preferably used.

The content of the silane coupling agent in at least one of the first sealing material 12 and the second sealing material 13 is 0.1 to 0.7 parts by mass, particularly 0.15 to 100 parts by mass with respect to 100 parts by mass of EVA. The amount is preferably 0.65 parts by mass.

At least one of the first sealing material 12 and the second sealing material 13 is an improvement or adjustment of various physical properties of the film (optical properties such as mechanical strength and transparency, heat resistance, light resistance, and crosslinking speed). Therefore, if necessary, it may further contain one or more additives selected from a plasticizer, an acryloxy group-containing compound, a methacryloxy group-containing compound, an epoxy group-containing compound, and the like.

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. A plasticizer may be used individually by 1 type in the above, and may be used in combination of 2 or more type. The plasticizer content in each of the first sealing material 12 or the second sealing material 13 is preferably in the range of 5 parts by mass or less with respect to 100 parts by mass of EVA.

The acryloxy group-containing compound and the methacryloxy group-containing compound are generally derivatives of acrylic acid or methacrylic acid, and examples include esters of acrylic acid or methacrylic acid. Examples of ester residues include linear alkyl groups such as methyl, ethyl, dodecyl, stearyl, lauryl, cyclohexyl group, tetrahydrfurfuryl group, aminoethyl group, 2-hydroxyethyl group, 3-hydroxypropyl group And 3-chloro-2-hydroxypropyl group.

Examples of the ester also include polyhydric alcohols such as ethylene glycol, triethylene glycol, polypropylene glycol, polyethylene glycol, trimethylolpropane, and pentaerythritol, and esters of acrylic acid or methacrylic acid.

Examples of the epoxy group-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 thereof include phenol (ethyleneoxy) glycidyl ether, pt-butylphenyl glycidyl ether, adipic acid diglycidyl ester, phthalic acid diglycidyl ester, glycidyl methacrylate, and butyl glycidyl ether.

The content of the acryloxy group-containing compound, the methacryloxy group-containing compound, or the epoxy group-containing compound in at least one of the first sealing material 12 and the second sealing material 13 is 0.5 for 100 parts by mass of EVA. It is preferably 5 to 5 parts by mass, particularly 1 to 4 parts by mass.

Furthermore, at least one of the first sealing material 12 and the second sealing material 13 may include an ultraviolet absorber, a light stabilizer, and a deterioration inhibitor.

When at least one of the first sealing material 12 and the second sealing material 13 includes an ultraviolet absorber, EVA is deteriorated due to the influence of irradiated light or the like, and the sealing material is prevented from yellowing. 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-methoxybenzophenone Preferred are benzophenone-based ultraviolet absorbers such as 2-hydroxy-4-n-octoxybenzophenone. The content of the benzophenone-based ultraviolet absorber in each of at least one of the first sealing material 12 and the second sealing material 13 is 0.01 to 5 parts by mass with respect to 100 parts by mass of EVA. preferable.

Even when at least one of the first sealing material 12 and the second sealing material 13 includes a light stabilizer, the deterioration of EVA due to the influence of irradiated light or the like, and the yellowing of the sealing material are suppressed. can do. 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 Are also manufactured by ADEKA Corporation), Tinuvin 744, Tinuvin 770, Tinuvin 765, Tinuvin 144, Tinuvin 622LD, CHIMASSORB 944LD (all manufactured by Ciba Specialty Chemicals Co., Ltd.), UV-3034 (BF Goodrich) Etc. In addition, the said light stabilizer may be used individually or may be used in combination of 2 or more type. The blending amount of the light stabilizer in each of the first sealing material 12 or the second sealing material 13 is preferably 0.01 to 5 parts by mass with respect to 100 parts by mass of EVA.

Examples of the degradation inhibitor 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 or sulfur heat stabilizers.

The thickness of the first sealing material 12 is preferably thicker than the thickness of the second sealing material 13. Thereby, the first sealing material 12 can absorb more stress applied to the solar cell module 20 than the second sealing material 13. For this reason, it can suppress that a water | moisture content etc. permeate the inside of the solar cell module 20 by peeling in the interface of the 1st sealing material 12 and the 1st protective material 11, and reduce generation | occurrence | production of a rust suitably. It becomes possible to do. The thickness of the first sealing material 12 is preferably 0.4 mm to 1.2 mm, particularly preferably 0.6 mm to 1.0 mm. On the other hand, the thickness of the second sealing material 13 is thinner than that of the first sealing material 12, and is preferably 0.2 mm to 0.8 mm, particularly 0.4 mm to 0.6 mm.

The first sealing material 12 and the second sealing material 13 described above may be formed according to a known method. For example, a sheet-like body can be produced from the composition containing the various components described above by a molding method such as ordinary extrusion molding or calendar molding (calendering). In particular, when molding is performed by hot rolling using a molding method such as extrusion molding, the heating at this time is generally in the range of 50 to 90 ° C.

When producing the 2nd sealing material 13 containing a coloring agent, a high concentration coloring agent is mixed with EVA beforehand, a masterbatch is produced, and other components mentioned above are further mixed with this masterbatch. It is preferable to obtain a composition from the viewpoint of highly dispersing the colorant.

Further, the composition is dissolved in a solvent, and this solution is coated on a suitable support with a suitable coating machine (coater), and then dried to form a coating film to obtain a sheet-like body. You can also.

As described above, a member to be sealed such as the solar cell element 10 is interposed between the first sealing material 12 and the second sealing material 13, and this member to be sealed can be sealed.

The solar cell element 10 generates light by receiving light. In order to obtain a high electromotive force in the general solar cell module 20, a plurality of solar cell elements 10 are connected in series or in series and parallel to each other. It is sealed between the sealing material 12 and the second sealing material 13.

The structure of the solar cell module 20 using the first sealing material 12 and the second sealing material 13 is not particularly limited. However, as shown in FIGS. 1 and 2, the second protective material 14 and the second sealing material are used. 13, the solar cell element 10, the 1st sealing material 12, and the translucent 1st protective material 11 are the structures arrange | positioned in these order. In other words, the structure of the solar cell module 20 includes the first sealing material 12 that covers the translucent first protective material 11 and the second sealing material 13 that covers the second protective material 14. The solar cell element 10 is disposed between the first sealing material 12 and the second sealing material 13 so as to come into contact with both the first sealing material 12 and the second sealing material 13. .

By cross-linking and curing EVA contained in at least one of the first sealing material 12 and the second sealing material 13, the solar cell element 10 is placed between the first sealing material 12 and the first sealing material 13. It can seal suitably. The solar cell element 10 is not only a solar cell element made of a single crystal or polycrystalline silicon substrate such as a silicon power generation element, but also a thin film solar cell element such as amorphous silicon or a compound of copper-indium-gallium-selenium. A solar cell element formed of a material such as CIGS or CdTc may be used. Moreover, the solar cell element 10 may adopt a back contact structure having electrodes only on the back surface.

In the solar cell module 20, in order to sufficiently seal the solar cell element 10, the transparent first protective material 11, the first sealing material 12, the solar cell element 10, the second sealing material 13, and the second. The protective material 14 may be laminated in this order, and the first encapsulant 12 and the second encapsulant 13 may be cured according to a conventional method such as heating and pressurizing the obtained laminate.

For heating and pressurizing, for example, the laminate is vacuum laminator at a temperature of 135 to 180 ° C., preferably 140 to 180 ° C., more preferably 155 to 180 ° C., degassing time 0.1 to 5 minutes, press pressure The pressure bonding may be performed under conditions of 11 to 147 kPa and a press time of 5 to 15 minutes.

The translucent first protective material 11 may be a glass substrate such as silicate glass, for example. The thickness of the glass substrate is generally from 0.1 to 10 mm, and preferably from 0.3 to 5 mm. The glass substrate may generally be chemically or thermally reinforced.

The second protective material 14 is a plastic film such as PET (polyethylene terephthalate). In consideration of heat resistance and heat-and-moisture resistance, a fluorinated polyethylene film, particularly a fluorinated polyethylene film / Al / fluorinated polyethylene film in this order. Laminated films are preferred.

The solar cell module 20 has the same configuration as the conventionally known solar cell module 20 with respect to members other than the sealing material such as the translucent first protective material 11, the second protective material 14, and the solar cell element 10. As long as it has, there is no particular limitation.

As mentioned above, although the embodiment according to the present invention has been illustrated, the present invention is not limited to the above-described embodiment, and it is needless to say that the embodiment can be arbitrary without departing from the gist of the present invention.

For example, the first sealing material 12 is made of EVA containing an organic nitrogen compound that functions as an acid acceptor, and the second sealing material 13 is a solar cell module made of non-ester thermoplastic resin without using EVA. It doesn't matter. The non-ester thermoplastic resin is, for example, a thermoplastic resin obtained by polymerizing a polyethylene compound containing an ethylene-α-olefin copolymer as a main component. Moreover, it does not produce a corrosion product such as acetic acid by hydrolysis, and has only to be flexible so as to relieve the impact applied to the solar cell element 10, and the compound to be polymerized is a cyclic olefin compound or vinyl instead of the polyethylene compound. Aromatic compounds, polyene compounds, propylene compounds, butene compounds, hexene compounds or octene compounds may be used, or one or more of these may be polymerized and used. The propylene compound is propylene polymerized with an ethylene-α-olefin copolymer. Similarly, the butene compound is butene polymerized with an ethylene-α-olefin copolymer, and the hexene compound is an ethylene-α-olefin. 1-hexene polymerized with the copolymer, and the octene compound is 1-octene polymerized with the ethylene-α-olefin copolymer.

Since the second sealing material 13 does not contain ester-based vinyl acetate as a difference from the first sealing material 12, acetic acid, which is a corrosive product, is added along with hydrolysis due to moisture absorption. It does not occur. The first sealing material 12 may be made of non-ester thermoplastic resin, and the second sealing material 13 may be made of EVA containing an organic nitrogen compound that functions as an acid acceptor. For example, it is preferable to use EVA for the first sealing material 12.

Further, the organic nitrogen compound is not uniformly dispersed in the sealing material in at least one of the first sealing material 12 and the second sealing material 13, but on the solar cell element 10 side, particularly in the solar cell element 10. The electrode and the wiring member 15 may be unevenly distributed so that the content thereof is larger than that of other regions.

In this case, first, for example, before the solar cell element 10 is sufficiently sealed, a sealing material having a high concentration of the organic nitrogen compound is previously disposed on the electrode and the wiring member 15, and at least the first sealing material. 11 or a part of the second sealing material 12 is formed. Thereafter, the first protective material 11, the (remaining) first sealing material 12, the solar cell element 10, the (remaining) second sealing material 13 and the second protective material 14 are arranged in this order. Laminate to form a laminate. And as above-mentioned, what is necessary is just to harden the 1st sealing material 12 and the 2nd sealing material 13 according to conventional methods, such as heating and pressurizing, to the obtained laminated body.

Thus, the organic nitrogen compound is unevenly distributed on the solar cell element 10 side in at least one of the first sealing material 12 and the second sealing material 13, thereby reducing the total content of the organic nitrogen compound. Thus, at least the generation of rust in the wiring member 15 or the electrode can be reliably and effectively reduced. As a result, the outstanding solar cell module which improved durability etc., without reducing electric power generation performance can be provided.

Next, an example that further embodies the above-described embodiment will be described.

First, sample No. which is a solar cell module 20 including one solar cell element 10 is manufactured by the manufacturing method described below. 1-15 was produced.

As the semiconductor substrate used for the solar cell element 10, five polycrystalline silicon substrates each having a square shape when viewed in plan, having a side of about 156 mm and a thickness of about 200 μm were prepared for each sample. These polycrystalline silicon substrates were doped with boron to exhibit a p-type conductivity type with a specific resistance of about 1.5 Ω · cm.

In addition, a concavo-convex structure (texture) was formed on the first surface 10a side of the polycrystalline silicon substrate by using the RIE (Reactive Ion Etching) method. Next, phosphorus is diffused by a vapor phase thermal diffusion method using phosphorus oxychloride (POCl ₃ ) as a diffusion source, and an n-type layer having a sheet resistance of about 90 Ω / □ is formed on the first surface 10a side of each polycrystalline silicon substrate. Formed.

The surface electrode 16 formed on the first surface 10a of the solar cell element 10 was prepared by applying a conductive paste made of silver to a linear pattern as shown in FIG. .

Further, the back electrode 17 formed on the second surface 10b of the solar cell element 10 is formed by first applying a conductive paste made of aluminum to a predetermined region by a screen printing method and then drying and baking simultaneously with the surface electrode 16. did. Thereafter, a conductive paste made of silver was applied to a linear pattern having the same shape as that of the front surface electrode 16 by a screen printing method, and then dried and baked to form a back electrode 17. Thereafter, lead wires made of copper foil having a predetermined length were soldered to the front electrode 16 and the back electrode 17 of the solar cell element 10.

Next, a first protective material 11 of white plate tempered glass having a size of about 180 mm square and a thickness of about 3.2 mm, a first sealing material 12 described later, the solar cell element 10, a second sealing material 13 described later The film-like second protective material 14 made of PET having a thickness of about 0.3 mm is laminated in this order, and the obtained laminate is subjected to the following heating and pressurizing method to form the first sealing material 12 and the second sealing material. The stop material 13 was softened and then integrated to produce the solar cell module 20. Note that the lead wires soldered to the front surface electrode 16 and the back surface electrode 17 of the solar cell element 10 were led out of the laminate so that the output characteristics could be measured after the solar cell module 20 was completed.

Here, both the first sealing material 12 and the second sealing material 13 are made of EVA, and when an acid acceptor is added to EVA, as shown in Table 1, with respect to 100 parts by mass of EVA. The content (part by mass) of the organic nitrogen compound (diethanolamine) was set. Moreover, the thickness of the 1st sealing material 12 was 0.7 mm, and the thickness of the 2nd sealing material 13 was 0.5 mm.

The heating and pressurization of the laminate was performed by pressing the laminate with a vacuum laminator at a temperature of about 170 ° C. under conditions of a deaeration time of about 3 minutes, a press pressure of about 108 kPa, and a press time of about 7 minutes.

Next, sample No. 1-15 (5 samples each) solar cell module was put into a constant temperature and humidity tester with a temperature of 125 ° C. and a relative humidity of 95%, and as shown in Table 1, the initial output (0 hour), 200 hours After and after 400 hours, the output was measured and the average value of each sample was determined. Further, Table 1 shows values obtained by dividing the output after 400 hours by the initial output (hereinafter referred to as output maintenance rate) for the output retention rate after 400 hours from the introduction of each sample into the constant temperature and humidity tester. Show. The output was measured under AM (Air Mass) 1.5 and 100 mW / cm ² irradiation conditions in accordance with JISC 8913.

Sample No. Regarding 1-15, deterioration of the electrodes provided on the front and back surfaces of the solar cell element 10 was visually observed.

As shown in Table 1, sample No. of solar cell module 20 in which the above organic nitrogen compound was not added to both the first sealing material 12 and the second sealing material 13. 15, the output maintenance ratio was as low as 0.650, and the deterioration of the electrode of the solar cell element 10 was confirmed visually. In response to this result, sample No. of a solar cell module in which the organic nitrogen compound was added to at least one of the first sealing material 12 and the second sealing material 13. In 1-14, the output maintenance ratio was 0.700 or more, and no deterioration of the electrode of the solar cell element 10 was confirmed, and it was confirmed that the durability of the solar cell module 20 was improved.

Sample No. 1-14, when the acid acceptor is contained only in EVA of the first sealing material, the initial output is 4. particularly when the content of the organic nitrogen compound is 0.075 parts by mass or more and 0.3 parts by mass or less. It was 104 W or more and the output maintenance ratio was 0.965 or more, and the good initial characteristics and durability of the solar cell module 20 were confirmed.

Sample No. 8-13, when the acid acceptor is contained only in EVA of the second sealing material, the initial output is 4.123 W or more particularly when the content of the organic nitrogen compound is 0.15 parts by mass or more and 1 part by mass or less. And the output maintenance factor was 0.950 or more, and the favorable durability of the solar cell module 20 could be confirmed. Moreover, in the thing whose content rate of an organic nitrogen compound is 0.01 mass part or less and 1.5 mass parts, the output maintenance factor was a low value of 0.893 or less. This is probably because the content of the organic nitrogen compound was too small, or the content was too large, resulting in insufficient polymerization of EVA, and the durability of the solar cell module 20 was lowered.

Furthermore, sample no. As can be seen from FIG. 14, the organic nitrogen compound may be contained in both the first sealing material 12 and the second sealing material 13, and the tendency is similar to that of the first sealing material 12 and the second sealing material 13. It was confirmed that the sample was the same as the sample containing an organic nitrogen compound.

DESCRIPTION OF SYMBOLS 10: Solar cell element 11: 1st protective material 12: 1st sealing material 13: 2nd sealing material 14: 2nd protective material 15: Wiring member 20: Solar cell module

Claims

A solar cell having a first surface which is a light receiving surface and a second surface located on the opposite side to the first surface;
A translucent first protective material disposed on the first surface side of the solar cell;
A second protective material disposed on the second surface side of the solar cell;
A first encapsulant disposed between the first surface of the solar cell and the first protective material;
A second encapsulant disposed between the second surface of the solar cell and the second protective material;
At least one of the first sealing material and the second sealing material includes an ethylene vinyl acetate copolymer and an organic compound having a functional group having nitrogen and functioning as an acid acceptor. .
The solar cell module according to claim 1, wherein the organic compound is diethanolamine.
The first sealing material contains the ethylene vinyl acetate copolymer and the organic compound, and 0.075 to 0.3 parts by mass of the ethylene vinyl acetate copolymer with respect to 100 parts by mass of the ethylene vinyl acetate copolymer. The solar cell module of Claim 1 or 2 containing the organic compound.
The second sealing material contains the ethylene vinyl acetate copolymer and the organic compound, and 0.15 to 1.0 part by mass of the ethylene vinyl acetate copolymer with respect to 100 parts by mass of the ethylene vinyl acetate copolymer. The solar cell module according to any one of claims 1 to 3, comprising an organic compound.
The first sealing material and the second sealing material contain an ethylene vinyl acetate copolymer and an organic compound having a functional group having nitrogen and functioning as an acid acceptor, and the second sealing material. The content of the organic compound with respect to the ethylene vinyl acetate copolymer in the inside is larger than the content of the organic compound with respect to the ethylene vinyl acetate copolymer in the first sealing material. A solar cell module according to claim 1.
The solar cell module according to any one of claims 1 to 5, wherein the second sealing material further contains a colorant.
The solar cell module according to any one of claims 1 to 6, wherein the second sealing material further contains a lubricant.
The solar cell module according to claim 7, wherein the lubricant is a phosphite compound.
The solar cell module according to any one of claims 1 to 8, wherein a thickness of the first sealing material is thicker than a thickness of the second sealing material.
The solar cell module according to any one of claims 1 to 9, wherein the organic compound is unevenly distributed on the solar cell side in at least one of the first sealing material and the second sealing material.