JP3032145B2 - Solar cell module - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improved solar cell module. In detail, the present invention seals the light incident side surface of a photovoltaic element with a coating material including at least two layers of a sealing material resin composed of a transparent organic polymer resin and a transparent surface protection film on the outermost surface. Related to solar cell modules.

[0002]

2. Description of the Related Art In recent years, awareness of environmental problems has been increasing worldwide. Above all, the fear of global warming caused by CO ₂ emission is serious, and the demand for clean energy is increasing more and more. Currently, solar cells are promising as a clean energy source because of their safety and ease of handling. By the way, there are various forms of solar cells. Representative examples include crystalline silicon solar cells, polycrystalline silicon solar cells, amorphous silicon solar cells, copper indium selenide solar cells, and compound semiconductor solar cells. Among these solar cells, crystalline silicon solar cells, compound semiconductor solar cells, and amorphous silicon solar cells can be made relatively large in area at a relatively low cost. I have.

[0003] Among these solar cells, a thin-film solar cell typified by an amorphous silicon solar cell in which silicon is deposited on a conductive metal substrate and a transparent conductive layer is formed thereon is lightweight and shock-resistant. Because of its high flexibility, it is promising as a future module form. However, unlike the case where silicon is deposited on a glass substrate, it is necessary to cover the light incident side surface with a transparent covering material to protect the solar cell. Therefore, by using a transparent fluoride polymer thin film such as a fluororesin film on the outermost surface as a surface coating material and various thermoplastic transparent organic resins inside the thin film solar cell, it is light and flexible utilizing the characteristics of thin film solar cells. There is a solar cell module with a certainty. The reason why these materials are used is (1)
Fluoropolymers are rich in weather resistance and water repellency, and can reduce a decrease in conversion efficiency of a solar cell module due to yellowing or white turbidity due to resin deterioration or a decrease in light transmittance due to surface contamination. (2) The thermoplastic transparent resin is inexpensive and can be used in large quantities as a sealing material for protecting the internal photovoltaic element.

In general, various collecting electrodes for efficiently extracting generated power and metal members for serializing or parallelizing the elements are provided on the solar cell element. The organic resin also has the effect of filling the irregularities on the element surface and smoothing the coating material surface by sealing the mounting members such as electrodes and metal members. However, such a module whose surface is covered with a film has a problem that the element is easily damaged unlike the case where the module is covered with glass. That is, the element can be easily damaged by scratching the surface with a sharp object. Therefore, in order to improve such a problem as much as possible, a reinforcing material is included in the organic resin, and a glass fiber nonwoven fabric is suitably used for this purpose. In addition, glass fiber non-woven fabric, in the module bonding process by vacuum heating compression method,
Since it is impregnated with the molten organic resin, it also has a role as a holding material for maintaining the thickness of the organic resin and a role of reducing residual air bubbles in the organic resin.

FIG. 1 is a schematic sectional view showing an example of a solar cell module. 103 is a fluororesin film such as an ETFE (ethylene-tetrafluoroethylene copolymer) film or PVF (polyvinyl fluoride) film, and 102 and 104 are thermal resins such as EVA (ethylene-vinyl acetate copolymer) and polyvinyl butyral. A plastic transparent organic resin 105 is various organic resin films including a nylon film and an aluminum laminated Tedlar film. In this example, the thermoplastic transparent organic resin serves as an adhesive for bonding the photovoltaic element and the resin film, and fills the unevenness of the surface mount member, and protects the solar cell from external scratches and impacts. Plays a role. The thermoplastic transparent organic resin 102 on the surface contains a glass fiber nonwoven fabric 106.

By the way, a solar cell module whose surface is covered with a film has a problem that a failure due to moisture is more likely to occur as compared with a case where it is covered with glass. This is because the film is permeable to water vapor or because water enters through holes in the film. In particular, the latter problem is serious, and when the water containing the electrolyte enters and reaches the element, the insulation between the element and the outside is easily broken, and the current leaks to the outside. When many solar cell modules are connected in series and used, the system voltage may be several hundred volts, and there is a risk of electric shock if insulation breakdown occurs.

Table 1 shows the results of measurement of the resistance between the element and the surface film after the conventional module surface was immersed in tap water for a certain period of time. As is clear from the table, it can be seen that the resistance value is greatly reduced by long-term immersion. One of the causes is that water that has entered through holes in the surface film reaches the element through the interface between the organic resin and the glass fiber constituting the sealing material. Table 1 also shows the resistance value when the glass fiber nonwoven fabric was not used, but the resistance value did not tend to decrease, confirming that the water intrusion path was at the interface between the resin and the glass fiber. .

[0008]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems in the prior art, and does not reduce the electrical insulation resistance of the coating material even when immersed in water containing an electrolyte for a long time.
It is an object of the present invention to provide a highly reliable solar cell module that does not have a risk of performance degradation or electric shock due to rainfall or flooding during long-term outdoor use.

[0009]

Means for Solving the Problems The present inventors have conducted intensive research and development to solve the above-mentioned problems, and as a result, have developed a solar cell module.
Silane coupling agent in the surface coating material of joule
When using glass fibers surface-treated with
It was out have seen that it is desirable solution. That is, the present onset
Akira is a sealing material resin with a transparent surface on the light incident side of the photovoltaic element.
In the solar cell module is coated with a coating material comprising at least two layers of the sealant resin layer and in that the contact transparent surface protective film disposed on the outermost surface of the outer consisting
Gas that has been previously surface-treated with a silane coupling agent.
Las fibers characterized <br/> containing Mukoto the encapsulant resin constituting the sealant resin layer.

[0010]

According to the above-described structure, the following effects can be obtained. (1) A decrease in insulation resistance of the coating material due to intrusion of water is suppressed. That is, the adhesiveness between the sealing resin and the glass fiber interface is improved by the silane coupling agent, and the water intrusion path is blocked. (2) Since the sealing material resin is an ethylene-vinyl acetate copolymer (EVA) resin containing a silane coupling agent, the adhesion between the sealing material resin and the glass fiber is further ensured. be able to. On the other hand, EVA is a resin conventionally used as a covering material of a solar cell module, and there is no need to largely change the current composition of the covering material. (3) Since the surface protective film is a resin film that has not been subjected to a stretching treatment, the surface film is less likely to break. Therefore, there is no water intrusion from the broken portion of the film, and further suppression of the decrease in the insulation resistance of the coating material can be expected. (4) When the surface protective film is made of a tetrafluoroethylene-ethylene copolymer resin, the coating has excellent weather resistance. That is, the weather resistance, transparency, and mechanical strength of the tetrafluoroethylene-ethylene copolymer resin can be expected. Further, the water repellency of the module surface is improved, the contamination of the solar cell module surface during long-term outdoor exposure can be suppressed, and a decrease in conversion efficiency can be reduced.

(5) Irregularities are formed on the surface of the coating material by forming irregularities on the surface of the coating material, and having a maximum height difference between adjacent concave portions and convex portions of 5 μm or more and 50 μm or less. In this case, breakage of the surface film can be prevented. Therefore, there is no water intrusion from the broken portion of the film, and further suppression of the decrease in the insulation resistance of the coating material can be expected. (6) Since the sealing resin layer is composed of a hard resin layer containing no glass fibers formed on the element surface and a soft resin layer containing glass fibers thereon, the insulation resistance of the surface coating material can be reduced. It can be further suppressed. That is, even if water invades along the soft resin layer containing glass fibers, the invasion can be stopped by the lower hard resin layer containing no glass fibers, so that water can be prevented from reaching the element. . (7) In addition, the photovoltaic element is formed by forming a semiconductor photoactive layer made of an amorphous silicon thin film and a transparent conductive layer as a light conversion member on a conductive substrate, so that the solar cell is excellent in flexibility. It can be a module. That is, since the photovoltaic element itself has excellent flexibility, a highly reliable flexible solar cell module that has enjoyed the effects of the present invention can be manufactured.

[0012]

FIG. 1 is a schematic structural view of a solar cell module according to the present invention. In FIG. 1, 101 is a photovoltaic element, 102 is a transparent sealing material resin on the front surface, 103 is a transparent surface protection film located on the outermost surface, 104 is a sealing material on the back surface, 105 is a back covering film, 106 Is a glass fiber nonwoven fabric. Light from the outside is transmitted to the outermost film 10
3, the light reaches the photovoltaic element 101, and the generated electromotive force is taken out from an output terminal (not shown). A typical photovoltaic element 101 according to the present invention is one in which a semiconductor photoactive layer as a light conversion member and a transparent conductive layer are formed on a conductive substrate. FIG. 2 shows a schematic configuration diagram as an example. In FIG. 2, reference numeral 201 denotes a conductive substrate, 2
02 is a back reflection layer, 203 is a semiconductor photoactive layer, 204 is a transparent conductive layer, 205 is a current collecting electrode, and 206 is an output terminal.

The conductive base 201 serves as a base for the photovoltaic element and also serves as a lower electrode. Materials include silicon, tantalum, molybdenum, tungsten,
Examples include stainless steel, aluminum, copper, titanium, carbon sheets, lead-plated steel sheets, resin films having a conductive layer formed thereon, and ceramics. On the conductive substrate 201, a metal layer, a metal oxide layer, or a metal layer and a metal oxide layer may be formed as the back surface reflection layer 202. For example, Ti, Cr, Mo, W, A
For example, ZnO, TiO ₂ , and SnO ₂ are used for the metal oxide layer. Examples of a method for forming the metal layer and the metal oxide layer include a resistance heating evaporation method, an electron beam evaporation method, and a sputtering method.

The semiconductor photoactive layer 203 is a portion that performs photoelectric conversion, and specific materials include pn junction type polycrystalline silicon, pin junction type amorphous silicon, and Cu.
InSe ₂ , CuInS ₂ , GaAs, CdS / Cu
₂ S, CdS / CdTe, CdS / InP, CdTe /
And a compound semiconductor such as Cu ₂ Te. As a method of forming the semiconductor photoactive layer, in the case of polycrystalline silicon, a sheet of molten silicon or heat treatment of amorphous silicon is used. In the case of amorphous silicon, plasma CVD using silane gas or the like is used. Plating, ion beam deposition,
There are a vacuum deposition method, a sputtering method, an electrodeposition method and the like. The transparent conductive layer 204 functions as an upper electrode of the solar cell.
As a material to be used, for example, In ₂ O ₃ , SnO ₂ , I
_{n 2 O 3 -SnO 2 (ITO} ), ZnO, TiO 2, Cd 2
Examples include SnO ₄ and a crystalline semiconductor layer doped with a high concentration of impurities. As the forming method, resistance heating evaporation, sputtering method,
There are a spray method, a CVD method, an impurity diffusion method and the like.

A grid-like current collecting electrode 205 (grid) may be provided on the transparent conductive layer in order to efficiently collect current. As a specific material of the current collecting electrode 205, for example, Ti, Cr, Mo, W, Al, Ag, Ni, C
u, Sn, or a conductive paste such as a silver paste. As a method for forming the current collecting electrode 205, sputtering using a mask pattern, resistance heating, a CVD method, a method in which an unnecessary portion is removed by etching after depositing a metal film on the entire surface and patterning is performed,
There are a method of directly forming a grid electrode pattern by photo-CVD, a method of forming a mask of a negative pattern of the grid electrode pattern and then plating, and a method of printing a conductive paste. As the conductive paste, one obtained by dispersing silver, gold, copper, nickel, carbon, or the like in fine powder form in a binder polymer is usually used. Examples of the binder polymer include resins such as polyester, epoxy, acrylic, alkyd, polyvinyl acetate, rubber, urethane, and phenol.

An output terminal 206 is attached to the conductive substrate and the current collecting electrode to extract an electromotive force. A method of joining a metal body such as a copper tab to the conductive base by spot welding or solder is used, and a method of electrically connecting the metal body to the current collecting electrode by a conductive paste or solder is used. The photovoltaic elements manufactured by the above method are connected in series or in parallel according to a desired voltage or current. Alternatively, a desired voltage or current can be obtained by integrating a photovoltaic element on an insulated substrate.

Next, the surface sealing material resin 1 used in the present invention
02, surface protection film 103 and glass fiber nonwoven fabric 1
06 will be described below. The surface sealing resin 102 covers the unevenness of the photovoltaic element with the resin, and changes the temperature of the element,
It is necessary to protect the device from the severe external environment such as humidity and impact and to ensure the adhesion between the surface film and the element. Therefore, weather resistance, adhesion, filling properties, heat resistance, cold resistance, and impact resistance are required. Resins satisfying these requirements include polyolefin-based resins such as ethylene-vinyl acetate copolymer (EVA), ethylene-methyl acrylate copolymer (EMA), ethylene-ethyl acrylate copolymer (EEA), and polyvinyl butyral resin. Resin, urethane resin,
Silicone resin, fluorine resin and the like can be mentioned. Among them, EVA has well-balanced physical properties for use in solar cells, and is preferably used. However, since the heat deformation temperature is low as it is, it easily deforms and creeps under high temperature use. Therefore, it is desirable to increase the heat resistance by crosslinking. In the case of EVA, it is common to crosslink with an organic peroxide. Crosslinking with an organic peroxide is performed by free radicals generated from the organic peroxide extracting hydrogen and halogen atoms in the resin to form a CC bond. Thermal decomposition, redox decomposition and ionic decomposition are known as methods for activating organic peroxides. Generally, a pyrolysis method is preferred. Specific examples of the chemical structure of the organic peroxide include hydroperoxide, dialkyl (allyl)
Peroxides, diacyl peroxides, peroxy ketals, peroxy esters, peroxy carbonates and ketone peroxides. The amount of the organic peroxide is 0.5 to 5 parts by weight based on 100 parts by weight of the sealing resin.

The above-mentioned organic peroxide is used in combination with a sealing resin,
Crosslinking and thermocompression bonding can be performed while heating under pressure under vacuum. The heating temperature and time can be determined by the thermal decomposition temperature characteristics of each organic peroxide. In general, the heating and pressurizing is completed at a temperature and a time at which the thermal decomposition proceeds by 90%, more preferably 95% or more. The gel fraction may be measured to confirm the crosslinking of the encapsulant resin. To prevent deformation of the encapsulant resin at a high temperature, the gel fraction must be 70 watts.
It is desirable to crosslink so that it becomes t% or more. In order to carry out the crosslinking reaction efficiently, triallyl isocyanurate (TAIC), which is called a crosslinking aid, can be used. Generally, the amount is 1 to 5 parts by weight based on 100 parts by weight of the sealing resin.

The material of the encapsulant resin used in the present invention is excellent in weather resistance. However, in order to further improve the weather resistance or to protect the lower layer of the encapsulant resin, an ultraviolet absorber is used in combination. You can also. Known compounds are used as the ultraviolet absorber, but it is preferable to use a low-volatile ultraviolet absorber in consideration of the usage environment of the solar cell module. Specific examples include salicylic acid, benzophenone, benzotriazole, and cyanoacrylate organic compounds. If a light stabilizer is also added in addition to the ultraviolet absorber, the sealing material resin becomes more stable to light. Representative light stabilizers are hindered amine light stabilizers. The hindered amine-based light stabilizer does not absorb ultraviolet rays unlike the ultraviolet absorber, but exhibits a remarkable synergistic effect when used in combination with the ultraviolet absorber. Of course, other than the hindered amine-based compounds, those which function as light stabilizers are often colored, which is not desirable for the encapsulant resin of the present invention. The amounts of the ultraviolet absorber and the light stabilizer added are 0.1 to 1.0 wt% and 0.05 to 1.0 w
t% is desirable. Further, an antioxidant can be added to improve heat resistance and heat workability. As the chemical structure of the antioxidant, there are monophenol type, bisphenol type, polymer type phenol type, sulfur type and phosphoric acid type. The addition amount of the antioxidant is 0.05 to 1.
It is preferably 0 wt%.

A silane coupling agent or an organic titanate compound can be added to the sealing resin in order to further improve the adhesiveness between the glass fiber and the sealing resin described later. It also has the effect of improving the adhesive strength between the encapsulant resin and the photovoltaic element or surface film. The amount of addition is 0.1 to 100 parts by weight of the sealing material resin.
1 to 3 parts by weight is preferable, and 0.25 to 1 part by weight is more preferable.

In order to minimize a decrease in the amount of light reaching the photovoltaic element, the surface sealing resin must be transparent, and specifically, has a light transmittance of 400 nm to 800 nm.
It is preferably at least 80%, more preferably at least 90% in the following visible light wavelength region. In addition, in order to facilitate the incidence of light from the atmosphere,
Preferably, the refractive index in degrees is from 1.1 to 2.0, more preferably from 1.1 to 1.6. An EVA sheet for a solar cell obtained by molding EVA containing the above additives into a sheet is commercially available. For example, Solar EVA manufactured by Hi-Sheet Industrial Co., Ltd., EVASAFE WG series manufactured by Bridgestone Corporation, and SPRINGGB
ORN LABORATORIES INC. Made PH
OTOCAP and the like. A solar cell module can be easily manufactured by inserting these between the photovoltaic element and the surface member and pressing them by heating.

Surface resin film 10 used in the present invention
Since No. 3 is located on the outermost layer of the solar cell module, it is necessary to have properties for ensuring long-term reliability of the solar cell module in outdoor exposure, including weather resistance, contamination resistance, and mechanical strength. Materials suitable for use in the present invention include fluorine resin and acrylic resin. Among them, fluororesins are preferably used because of their excellent weather resistance and stain resistance. Specific examples include a polyvinylidene fluoride resin, a polyvinyl fluoride resin, and an ethylene tetrafluoride-ethylene copolymer. Polyvinylidene fluoride resin is excellent in terms of weather resistance, but ethylene tetrafluoride-ethylene copolymer is excellent in terms of compatibility between weather resistance and mechanical strength and transparency. The thickness of the surface resin film must be somewhat large in order to ensure mechanical strength, and there is a problem that it is too thick from the viewpoint of cost. Specifically, 20 to 200 micrometers is preferable,
More preferably, it is 30 to 100 micrometers.

In order to improve the adhesion to the encapsulant resin, it is desirable to perform a surface treatment such as a corona treatment, a plasma treatment, an ozone treatment, a UV irradiation, an electron beam irradiation and a flame treatment on one surface of the surface film. . Among them, the corona discharge treatment is preferably used because the treatment speed is high and a relatively simple apparatus can greatly improve the adhesive force.

The surface of the coating material is often provided with irregularities in consideration of reduction of reflected light, suppression of wrinkling at the time of bonding, designability, and the like. In this case, the surface protective film of the irregularities is stretched. May break. When the surface protective film breaks, water invades from the surface protective film, and dielectric breakdown of the coating material easily occurs. Therefore, in order to prevent this, it is preferable that the surface protective film is not stretched. If it is not stretched, it is stretched following the irregularities, so that breakage is unlikely to occur. Further, it is desirable that the maximum height difference between the concave portion and the convex portion adjacent to the concave and convex portions is not less than 5 micrometers and not more than 100 micrometers. If it is less than 5 micrometers, the effect of providing the unevenness is not sufficiently exhibited, and
If it exceeds 0 micrometer, the surface protective film is likely to break. The unevenness may be provided during the coating forming step, or may be provided by a method such as pressing after the coating is formed.

The glass fiber nonwoven fabric 106 contained in the surface sealing material resin layer has been treated with a silane coupling agent. Specific silane coupling agents include vinyltrichlorosilane, vinyltris (β-methoxyethoxy) silane, vinyltriethoxysilane, vinyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, β- (3,4-epoxycyclohexyl) )
Ethyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, N-β (aminoethyl) γ-
Aminopropyltrimethoxysilane, N-β (aminoethyl) γ-aminopropylmethyldimethoxysilane, γ
-Aminopropyltriethoxysilane, N-phenyl-
γ-aminopropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-chloropropyltrimethoxysilane, and the like. Examples of the treatment method include a spray method in which an alcohol solution or an aqueous solution of a silane coupling agent is sprayed on the nonwoven fabric, a dipping method in which the nonwoven fabric is dipped in the solution, and a gravure coating method in which the nonwoven fabric is passed between rolls wet with the solution.

In this embodiment, a glass fiber nonwoven fabric is preferably used, but a woven fabric may be used. However, in this case, care must be taken since the impregnating property of the resin is inferior to that of the nonwoven fabric and the transparency of the resin may be impaired. The covering film 105 on the back surface is necessary for maintaining electrical insulation between the conductive substrate of the photovoltaic element 101 and the outside. As the material, a material which can secure sufficient electric insulation with the conductive substrate, has excellent long-term durability, can withstand thermal expansion and thermal contraction, and has flexibility is preferable. Suitable films include nylon and polyethylene terephthalate.

The encapsulant 104 on the back is a photovoltaic element 101
And the backing film 105 for adhesion. As the material, a material that can secure sufficient adhesiveness to the conductive substrate, has excellent long-term durability, can withstand thermal expansion and thermal contraction, and has flexibility is preferable. Suitable materials include hot melt materials such as EVA, EEA and polyvinyl butyral, double-sided tapes, and flexible epoxy adhesives. Of course, the same material as the surface sealing material can be used, and such a case is usually common. A reinforcing plate may be attached to the outside of the back cover film in order to increase the mechanical strength of the solar cell module, or to prevent distortion and warpage due to a temperature change. For example, steel plate, plastic plate,
FRP (glass fiber reinforced plastic) plates are preferred.

On the surface of the photovoltaic element, a resin layer containing no glass fiber nonwoven fabric may be provided so as to be in contact with the element separately from the surface sealing resin containing the above glass fiber nonwoven fabric. Examples of the material of the resin layer include an acrylic resin, an epoxy resin, a fluororesin, an EVA resin, an EMA resin, an EEA resin, a polyvinyl butyral resin, a silicone resin, an acrylic silicone resin, a polyorganosiloxane resin, and a urethane resin. It is desirable that the material be excellent in weather resistance in consideration of the usage environment of the solar cell module. Further, it is more preferable that the resin is crosslinked in order to prevent softening under high temperature use.

A method for forming a solar cell module using the above-described photovoltaic element, sealing resin, surface protection film, glass fiber nonwoven fabric, and backside covering film will be described below. To cover the photovoltaic element light-receiving surface with a sealing material resin, a surface protection film, and a glass fiber non-woven fabric, create a sheet-shaped sealing material resin and place it on the device together with the surface protection film and the glass fiber non-woven fabric. The method of thermocompression bonding is common. That is, a solar cell module can be obtained by inserting a sealing material resin sheet and a glass fiber nonwoven fabric between the photovoltaic element and the surface protection film, and heat-pressing. At this time, if a material having an irregular shape is arranged outside the surface protective film and the material is pressed against the surface protective film at the time of pressing, irregularities can be easily provided on the surface of the covering material. In addition, the heating temperature and heating time at the time of press bonding are determined by the temperature and time at which the crosslinking reaction sufficiently proceeds.

Also, the back surface may be covered in the same manner using the back cover film and the back sealing material. Usually, the surface sealing material and the back surface sealing material are made of the same material, and thus can be performed simultaneously with the above-described process. Various known methods such as vacuum lamination and roll lamination can be used as the thermocompression bonding method. That is, a photovoltaic element, a sealing material sheet, a glass fiber nonwoven fabric,
The surface protective film and the backside covering film are laminated in the order of, for example, a surface protecting film / sealing material sheet / glass fiber nonwoven fabric / photovoltaic element / sealing material sheet / backside covering film to form a solar cell module laminate, which is heat-pressed. For example, it can be a solar cell module. The glass fiber non-woven fabric aids in deaeration of the gap between the laminates in the evacuation step by the vacuum lamination method, and is impregnated with the EVA melted in the heating step, so that the EVA flows out to the end of the module and the sealing resin becomes thinner. There is a function to prevent it. Furthermore, by being impregnated in EVA,
Since it functions as a reinforcing material for VA, it also has the effect of making it difficult for surface damage to reach the element.

[0031]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

[0032]

Embodiment 1

[Preparation of Photovoltaic Element] An amorphous silicon (a-Si) solar cell (photovoltaic element) having the structure shown in FIG. 2 was prepared. On the cleaned stainless steel substrate 201, an Al layer (film thickness: 5000 °) as a back reflection layer 202 by a sputtering method.
And a ZnO layer (thickness 5000 °) are sequentially formed. Next, an n-type a-Si layer was formed from a mixed gas of SiH ₄ , PH ₃ and H _2, an i-type a-Si layer was formed from a mixed gas of SiH ₄ and H ₂ , and SiH ₄ and BF ₃ were formed by plasma CVD. A p-type microcrystalline μc-Si layer is formed from a mixed gas of H ₂ ,
A tandem a-Si photoelectric conversion semiconductor layer 203 having a layer structure of 50 ° / i-layer thickness 4000 ° / p-layer thickness 100 ° / n-layer thickness 100 ° / i-layer thickness 800 ° / p-layer thickness 100 ° was formed. Next, as the transparent conductive layer 204, an In ₂ O ₃ thin film (thickness: 700 °) was formed by vapor deposition of In by a resistance heating method in an O ₂ atmosphere. Further, a grid electrode 205 for current collection is formed by screen printing of silver paste, and finally a copper tab is attached to the stainless steel substrate as the negative terminal 206b using the stainless solder 208, and a tin foil tape is used as the positive terminal 206a. A photovoltaic element was obtained by attaching to the collecting electrode 205 with the conductive adhesive 207 to serve as an output terminal. In addition, the plus side terminal was turned to the back surface via an insulator so that an output could be taken out from a hole of a back surface covering material described later. Thus, a plurality of photovoltaic elements were obtained.

[0033]

[Modularization] The obtained photovoltaic element was coated as shown in FIG. 3 to produce a solar cell module. That is, the surface of the photovoltaic element 301 is coated with an acrylic silicone thermosetting paint (trade name: Fine Hard, manufactured by Tonen)
Was applied by spraying, and then dried at 200 ° C. for 30 minutes to form a resin layer 304. Next, the element,
Glass fiber non-woven fabric 308 (manufactured by Crane, product name: Crane glass 230), EVA sheet 302 (Springbone Laboratories, product name: Photocap,
Unstretched ETFE film 303 having a thickness of 460 μm) and having one surface subjected to corona discharge treatment (manufactured by DuPont)
Product name Tefzel film, thickness 50 micrometers), nylon film 305 (Dupont, product name Dartec, thickness 63.5 micrometers), galvalume steel plate 306 (product of Daido steel plate, product name Timer color GL, thickness) 0.27 mm) in order of ETFE / EVA / glass fiber nonwoven fabric / element / EVA / nylon / EVA / steel sheet to obtain a solar cell module laminate. The glass fiber non-woven fabric is sprayed with a 0.5% alcohol solution of γ-methacryloxypropyltrimethoxysilane (manufactured by Dow Corning Silicone Toray Co., Ltd., product number SZ6030) on both sides by spraying, and then dried to dryness. The silane coupling treatment was performed.

A stainless steel mesh (40 × 40 mesh, wire diameter 0.15 mm) was put on the outside of the ETFE through a Teflon film for release (Teflon PFA film, trade name, manufactured by DuPont), thickness of 50 μm. Arranged. The laminate was heat-pressed at 150 ° C. for 30 minutes while being degassed under pressure using a vacuum laminating apparatus to obtain a solar cell module having a surface having irregularities with a height difference of up to 30 μm formed by a mesh.
Thus, a plurality of solar cell modules were manufactured. The EVA sheet used here is widely used as a sealing material for a solar cell, and a crosslinking agent 1.5 parts by weight based on 100 parts by weight of an EVA resin (33% vinyl acetate content).
Parts by weight, 0.3 parts by weight of ultraviolet absorber, 0.1 light stabilizer
Parts by weight, 0.2 parts by weight of an antioxidant, and 0.25 parts by weight of a silane coupling agent. The output terminal was previously turned on the back surface of the photovoltaic element, and after lamination, the output could be taken out from the terminal outlets 307a and 307b that had been opened in advance on the galvalume steel plate.

[0035]

[Evaluation] The following procedure was used to evaluate the change in electrical insulation resistance during long-term water immersion of the produced module surface covering material. That is, after immersing the surface of the module in tap water for a certain period, a metal plate is pressed against the entire surface of the module, and a DC voltage of 2,000 volts is applied between the output terminal and the metal plate having the plus and minus sides short-circuited. The resistance value per unit area of the surface covering material covering the element was calculated from the flowing current. The obtained result is shown in a graph in FIG.

[0036]

Example 2 A solar cell module was produced in the same manner as in Example 1, except that a commercially available glass fiber nonwoven fabric (manufactured by Honshu Denshi Co., Ltd., trade name: Graspar) which had been subjected to aminosilane coupling treatment was used as the glass fiber nonwoven fabric. Was prepared. The obtained solar cell module was evaluated in the same manner as in Example 1. The obtained evaluation results are shown in a graph in FIG.

[0037]

Example 3 A solar cell module was manufactured in the same manner as in Example 1 except that the resin layer 304 was not formed. The obtained solar cell module was evaluated in the same manner as in Example 1. The obtained evaluation results are shown in a graph in FIG.

[0038]

Embodiment 4 The maximum height difference 1 was changed by changing the mesh used for forming the irregularities in Embodiment 1 to a stainless mesh of 16 × 16 mesh (wire diameter 0.27 mm).
Example 1 except that irregularities of 60 micrometers were formed.
In the same manner as in the above, a solar cell module was produced. The obtained solar cell module was evaluated in the same manner as in Example 1. The obtained evaluation results are shown in a graph in FIG.

[0039]

Example 5 A solar cell module was manufactured in the same manner as in Example 1 except that an acrylic resin film (trade name: Acryprene, manufactured by Mitsubishi Rayon, 125 μm in thickness) was used as the surface protective film. The obtained solar cell module was evaluated in the same manner as in Example 1. The obtained evaluation results are shown in a graph in FIG.

[0040]

Example 6 A solar cell module was prepared in the same manner as in Example 1 except that an ETFE film (Tefzel T2 film, trade name, manufactured by DuPont, having a thickness of 38 micrometers) obtained by uniaxially stretching the surface protective film was used. Was prepared. The obtained solar cell module was evaluated in the same manner as in Example 1. The obtained evaluation results are shown in a graph in FIG.

[0041]

Example 7 A solar cell module was manufactured in the same manner as in Example 1, except that an EVA sheet containing no silane coupling agent was used. The obtained solar cell module was evaluated in the same manner as in Example 1.
The obtained evaluation results are shown in a graph in FIG.

Further, in order to further clarify the effects of the embodiment, a module of the following comparative example was manufactured.

Comparative Example 1 A solar cell module was manufactured in the same manner as in Example 1 except that the silane coupling treatment of the glass fiber nonwoven fabric was not performed. The obtained solar cell module was evaluated in the same manner as in Example 1.
The obtained evaluation results are shown in a graph in FIG.

[0043]

Comparative Example 2 A solar cell module was manufactured in the same manner as in Example 1 except that no glass fiber nonwoven fabric was used. The obtained solar cell module was used in Example 1.
The evaluation was performed in the same manner as in the above. The obtained evaluation results are shown in a graph in FIG.

As is clear from FIG. 4, all of the solar cell modules of the examples were able to suppress the lowering of the insulation resistance as compared with Comparative Example 1 in which the glass fiber nonwoven fabric was not subjected to the silane coupling treatment. In Comparative Example 2, since no glass fiber nonwoven fabric was used, there was no water intrusion path, and the insulation resistance did not decrease. However, since there is no function of the nonwoven fabric as a holding material and a reinforcing material for the sealing material, the element is easily scratched by scratching, and is not practical as a covering material for a module used in a severe outdoor environment. I couldn't say it.

[0045]

[Table 1]

[0046]

According to the present invention, at least two layers of the transparent encapsulant resin layer and the outermost outer surface of the transparent encapsulation resin layer in contact with the light incident side surface of the photovoltaic element are provided. In a solar cell module covered with a covering material containing, the sealing material resin layer contains a glass fiber as a resin reinforcing material and a resin holding material in a resin, and the surface of the glass fiber is a silane coupling agent. By being treated, the electrical insulation resistance of the coating material does not decrease even when immersed in water containing an electrolyte for a long period of time. A highly reliable solar cell module can be provided.

[Brief description of the drawings]

FIG. 1 is an example of a schematic cross-sectional view of a solar cell module.

FIGS. 2A and 2B are a schematic sectional view 2A and a light-receiving-side top view 2B, respectively, showing a basic configuration of a photovoltaic element used in the solar cell module of FIG.

FIG. 3 is a schematic sectional view of a solar cell module of the present invention and a sectional view of a laminate before bonding.

FIG. 4 is a graph showing a change in insulation resistance of a surface covering material of a solar cell module obtained in Examples and Comparative Examples.

[Explanation of symbols]

 101,301 Photovoltaic element 102 Surface sealing resin 103,303 Surface protective film 104 Back sealing material 105 Back coating film 106,309 Glass fiber nonwoven fabric 302 EVA 304 Resin layer 305 Nylon film 306 Steel plate 307 Terminal 308 Terminal outlet 310 solar cell module laminate 201 conductive substrate 202 back reflection layer 203 semiconductor photoactive layer 204 transparent conductive layer 205 current collecting electrode 206 terminal 207 conductive paste 208 solder

Continued on the front page (72) Inventor Ayako Komori 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc. (72) Inventor Hidenori Shiozuka 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc. (56) References JP-A-53-110492 (JP, A) JP-A-7-131048 (JP, A) JP-A-6-334207 (JP, A) JP-A-58-60579 (JP, A) ( 58) Field surveyed (Int.Cl. ⁷ , DB name) H01L 31/04-31/078

Claims (8)

(57) [Claims] 1. A sealing in which a light incident side surface of a photovoltaic element is transparent.
A solar cell module covered with a covering material including at least two layers of a sealing material resin layer made of a material resin and a transparent surface protection film located on the outermost surface in contact with the resin material, the silane coupling being performed in advance. Surface treated with agent
Solar cell module which is characterized in including that the glass fibers in the sealing material tree <br/> in fat constituting the sealant resin layer. 2. The method according to claim 1, wherein the glass fiber is previously silane-coupled.
The solar cell module according to claim 1, wherein the sealing resin is impregnated with a glass fiber nonwoven fabric surface-treated with an agent . 3. The solar cell module according to claim 1, wherein the encapsulant resin is an ethylene-vinyl acetate copolymer (EVA) resin containing a silane coupling agent. 4. The solar cell module according to claim 1, wherein the surface protective film is a resin film that has not been subjected to a stretching treatment. The solar cell module according to claim 4 is made of an ethylene copolymer resin - wherein said resin film is polytetrafluoroethylene. 6. The coating material according to claim 1, wherein irregularities are formed on a surface of the coating material , and a maximum height difference between adjacent concave portions and convex portions is 5 μm or more and 100 μm or less.
A solar cell module according to item 1. 7. The photovoltaic element according to claim 7, wherein said encapsulant resin layer is formed of light.
And a resin layer comprising the glass fibers provided resin layer not containing the glass fibers, et al is provided on the incident surface and thereon
The solar cell module according to claim 1 in which those composed. 8. in which the formed of amorphous silicon thin film as a photoelectric conversion <br/> switching member to the photovoltaic element is a conductive substrate a semiconductor photoactive layer and a transparent conductive layer formed in claim 1 The solar cell module as described.