JP2013229576A - Solar cell module and member for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a solar cell module which enables electric wires connecting solar battery cells to reflect solar light and inhibit a surface of the solar cell module from glistening without deteriorating the generating efficiency, is excellent in safety, and achieves high quality design.SOLUTION: A solar cell module is formed by sealing a photoelectric conversion layer including one or more solar battery cells, which are connected by a reinforcement layer and electric wires, between a front surface protection layer and a rear surface protection layer. The front surface protection layer, the reinforcement layer, the photoelectric conversion layer, and the rear surface protection layer are laminated from the solar light receiving surface side in this order. Further, the reinforcement layer is decorated.

Description

  The present invention relates to a solar cell module and a vehicle member on which the solar cell module is mounted.

As a solar cell, for example, a solar cell using single crystal silicon or polycrystalline silicon is known.
These solar cells normally constitute a solar cell module in a state of being sealed between protective members (protective layer) with a sealing material such as EVA resin. Specifically, these solar cell modules are sandwiched between an EVA resin film, etc., sandwiching a photoelectric conversion layer in which one or more solar cells are connected with an electric wire between protective layers such as a surface protective layer and a back surface protective layer, Generally, the entire module is vacuum-produced by heating and pressing with a vacuum laminator.

  The solar cell module obtained in this way, for example, when the solar cell module is installed on a window or roof, the back surface of the solar cell module can be seen from the inside, giving the person only an unpleasant impression in the killing scenery. In recent years, various contrivances have been made to improve the design of solar cell modules. For example, Patent Document 1 describes a solar cell module in which coloring means is provided on the back surface side of the solar cell, and Patent Document 2 describes the side opposite to the light incident side with respect to the solar cell of the solar cell module. Describes a solar cell module provided with a translucent material and a printed matter having a desired pattern between the solar cell and the building constituent material.

JP 2000-299482 A JP 2001-326373 A

  Since the electric wires connecting the solar cells seal the solar cells in the solar cell module, the thickness thereof can be reduced as much as possible, and from the viewpoint of ease of pressure molding with a terminator, in general, metal Bare wires with exposed conductors and copper wires covered with metals such as lead are used. In order to improve the power generation efficiency of the solar cell, if a material with high translucency is used by the surface protective layer, there is a problem that sunlight is reflected by the metal electric wire and the surface of the solar cell module is glared. . In particular, in a vehicle or the like on which such a solar cell module is mounted, if the surface of the solar cell module is glaring, there is a possibility that human vision is obstructed and the vehicle or the like is not noticed.

  The present invention has been made in view of the above problems, and without reducing the power generation efficiency of the solar cell module, the electric wire connecting the solar cells reflects sunlight and the surface of the solar cell module is glazed. It is an object to provide a solar cell module having high design and excellent safety.

As a result of intensive studies to solve the above-mentioned problems, the inventors of the present invention, in a solar cell module in which a photoelectric conversion layer and a reinforcing layer are sealed between a surface protective layer and a back surface protective layer, The surface protective layer, the reinforcing layer, the photoelectric conversion layer, and the back surface protective layer are laminated in this order, and by using the decorative sheet, the decorative sheet can suppress the sunlight from being applied to the electric wire part. The inventors have found that the reflection of sunlight by the electric wire is reduced and the surface of the solar cell module is not glazed, and the present invention has been completed.

That is, the gist of the present invention resides in the following [1] to [5].
[1] A solar cell module in which a photoelectric conversion layer including one or more solar cells connected by a reinforcing layer and an electric wire is sealed between a front surface protective layer and a back surface protective layer, the solar light receiving surface A solar cell module, wherein a surface protective layer, a reinforcing layer, a photoelectric conversion layer, and a back protective layer are laminated in this order from the side, and the reinforcing layer is decorated.
[2] The solar cell module according to [1], wherein the reinforcing layer is decorated on a wiring pattern of the electric wire included in the photoelectric conversion layer existing on the sunlight receiving surface side.
[3] The solar cell module according to [1] or [2], further including a reinforcing layer between the photoelectric conversion layer and the back surface protective layer.
[4] The solar cell module according to any one of [1] to [3], wherein the material of the reinforcing layer is glass or a stretched polyester resin sheet.
[5] A vehicle member having the solar cell module according to any one of [1] to [4].

  ADVANTAGE OF THE INVENTION According to this invention, it can suppress that the electric wire of a photoelectric converting layer reflects sunlight, and can provide the solar cell module for vehicle mounting excellent in the design property optimal especially when mounting in a vehicle etc. In addition, the presence of the reinforcing layer between the photoelectric conversion layer and the surface protective layer damages the solar cells in the photoelectric conversion layer due to internal stress generated by the material of the surface protective layer when the solar cell module is molded with a vacuum laminator. It is possible to suppress the buckling of the electric wire.

BRIEF DESCRIPTION OF THE DRAWINGS It is the schematic diagram (sectional drawing which shows a layer structure) of one embodiment of the solar cell module of this invention (solar cell module 1 of Example 1). It is the schematic of the wiring of the electric wire in the photoelectric converting layer which looked at the solar cell module 1 of Example 1 which is one embodiment of the solar cell module of this invention from the sunlight light-receiving surface side, and a photovoltaic cell. It is the schematic diagram which showed the pattern of the decoration of the reinforcement layer which looked at the solar cell module 1 of Example 1 which is one embodiment of the solar cell module of this invention from the sunlight light-receiving surface side. It is a schematic diagram (sectional drawing which shows a layer structure) of the other embodiment of a solar cell module (solar cell module 2 of the comparative example 1). It is a schematic diagram (sectional drawing which shows a layer structure) of one embodiment of the solar cell module of this invention (solar cell module 3 of Example 2). It is the schematic diagram which showed the pattern of the decoration of the reinforcement layer which looked at the solar cell module 3 of Example 2 which is one embodiment of the solar cell module of this invention from the sunlight light-receiving surface side. It is a schematic diagram (sectional drawing which shows a layer structure) of one embodiment of the solar cell module of this invention (solar cell module 4 of Example 3). It is the schematic diagram which showed the pattern of the decoration of the reinforcement layer which looked at the solar cell module 4 of Example 2 which is one embodiment of the solar cell module of this invention from the sunlight light-receiving surface side.

Embodiments of the solar cell module of the present invention will be specifically described below.
<Surface protective layer>
In the present invention, the surface protective layer is a layer for imparting mechanical strength, weather resistance, scratch resistance, chemical resistance, gas barrier properties and the like to the solar cell module. As the surface protective layer, a resin (hereinafter sometimes referred to as “resin (A)”) is preferably used. From the viewpoint of supplying a large amount of sunlight to the photoelectric conversion layer, the total light transmittance of the resin (A) is 80% or more, preferably 90% or more. The measuring method of a total light transmittance is based on JISK7361-1, for example.

  Examples of the resin (A) used for the surface protective layer include polycarbonate (PC), polymethyl methacrylate (PMMA), cyclic polyolefin, polystyrene, polyethylene terephthalate (PET), polyethylene naphthalate (PEN), and ethylene-tetrafluoroethylene copolymer. Examples thereof include a polymer (ETFE), polytetrafluoroethylene (PTFE), polypropylene (PP), and polyethylene (PE). Preferably, polycarbonate (PC) resin, polymethyl methacrylate (PMMA), ethylene-tetrafluoroethylene copolymer (ETFE), etc. are mentioned. The surface protective layer may have a multilayer structure using a plurality of these resins. In that case, it is preferable to provide a sealing material layer between the layers.

  The method for obtaining these resins is not particularly limited, and commercially available products can be used. For example, polycarbonate plates made by Takiron Co., Ltd., “Iupilon (registered trademark)” manufactured by Mitsubishi Engineering Plastics Co., Ltd., and polymethyl methacrylate, “Acrylite (registered trademark)” manufactured by Mitsubishi Rayon Co., Ltd., Sumitomo Chemical ( “SUMIPEX (registered trademark)” manufactured by KK and ETFE include ETFE (model: 100HK-DCS) manufactured by Asahi Glass Co., Ltd.

  The thickness of the resin (A) is usually 0.1 mm or more when a photovoltaic cell such as a polycrystalline silicon cell or a single crystal silicon cell is used for the photoelectric conversion layer. The thickness is preferably more than 0.5 mm, more preferably 1.0 mm or more, and even more preferably 1.5 mm or more. If it is less than 0.1 mm, the impact resistance is remarkably lowered. On the other hand, the upper limit is not particularly limited, but is preferably 5 mm or less. If the resin becomes too thick, the flexibility of the resin layer is reduced and the weight of the module is increased, so that the merit of using the solar cell module substrate as the resin is lost.

  When using photovoltaic cells such as amorphous silicon cells, microcrystalline silicon cells, compound solar cells such as CIGS, organic thin film solar cells, and dye-sensitized solar cells for the photoelectric conversion layer, usually 0.01 mm or more It is. The thickness is preferably more than 0.02 mm, more preferably 0.05 mm or more, and still more preferably 0.1 mm or more. If it is less than 0.01 mm, impact resistance and tear strength are significantly reduced. On the other hand, the upper limit is not particularly limited, but is preferably 5 mm or less. If the resin becomes too thick, the flexibility of the resin layer is reduced and the weight of the module is increased, so that the merit of using the solar cell module substrate as the resin is lost.

Moreover, the magnitude | size of the laminated surface of a surface protective layer should just have an area larger than the laminated surface of the photoelectric converting layer which has the photovoltaic cell mentioned later normally. The area of the lamination surface here means the area of the surface perpendicular to the thickness direction of the surface protective layer. A photoelectric conversion layer can fully be protected because the area of the lamination surface of a surface protective layer is larger than the area of the lamination surface of a photoelectric conversion layer.
Moreover, since a solar cell module is heated by sunlight, it is preferable that a surface protection sheet has heat resistance. Therefore, the constituent material of the surface protective sheet preferably has a melting point of 100 ° C. or higher, and more preferably 120 ° C. or higher. On the other hand, the upper limit of the melting point is preferably 320 ° C. or lower.

<Photoelectric conversion layer>
In the present invention, the photoelectric conversion layer is a layer that generates power based on sunlight incident from the light receiving surface side. The photoelectric conversion layer only needs to be capable of converting light energy into electric energy and taking out the electric energy obtained by the conversion to the outside. The photoelectric conversion layer includes one or more solar cells, and the photoelectric conversion layer may be formed by connecting a plurality of solar cells with an electric wire (interconnector). The electric energy obtained in the photoelectric conversion layer can be taken out via an external converter through a collecting wire.

In the present invention, the material of the electric wire is not particularly limited, but it is preferable to use a highly conductive metal material. Specifically, silver, copper, aluminum, copper alloy, aluminum alloy, copper plated with tin, lead-free solder-coated copper wire, or the like can be used.
Therefore, as a photoelectric conversion layer, a solar battery cell in which a power generation layer is sandwiched between a pair of electrodes, a solar battery cell in which a stacked body of a power generation layer and another layer (buffer layer, etc.) is sandwiched between a pair of electrodes, and the like It is possible to use those including a plurality of such connected in series or / and in parallel.

  Various power generation layers can be adopted as the photoelectric conversion layer, but the power generation layer is thin film single crystal silicon, thin film polycrystalline silicon, amorphous silicon, microcrystalline silicon, CdTe, Cu-In- (Ge). It is preferable to use an inorganic semiconductor material such as Se, an organic dye material such as a black die, or an organic semiconductor material such as a conjugated polymer / fullerene, but from the viewpoint of power generation efficiency, thin film single crystal silicon or thin film polycrystalline silicon Is more preferable. For example, commercially available silicon solar cells may be used, and examples include solar cells such as those manufactured by Q-Cells, First Solar, Suntech, Sharp, Shinsung, Gintech, and Sunpower. .

Further, a multi-junction photoelectric conversion layer, a HIT photoelectric conversion layer, or the like may be employed.
In order to realize higher power generation efficiency, it is preferable to provide a sufficient light confinement structure, such as forming an uneven structure on the surface of the power generation layer or on the photoelectric conversion layer substrate that is installed as necessary.
If the power generation layer is an amorphous silicon layer, a photoelectric conversion layer that has a large optical absorption coefficient in the visible region and can sufficiently absorb sunlight even with a thin film having a thickness of about 1 μm can be realized. In addition, amorphous silicon, microcrystalline silicon, inorganic semiconductor materials, organic dye materials, and organic semiconductor materials are non-crystalline materials or materials with low crystallinity, and thus have resistance to deformation. Therefore, if an amorphous silicon layer is provided as a power generation layer, a solar cell module that is particularly lightweight and has a certain degree of resistance to deformation can be realized.

If an inorganic semiconductor material (compound semiconductor) is used for the power generation layer, a photoelectric conversion layer with high power generation efficiency can be realized. From the viewpoint of power generation efficiency (photoelectric conversion efficiency), the power generation layer is preferably a chalcogenide-based power generation layer containing a chalcogen element such as S, Se, Te, etc. I-III-VI2 group semiconductor system (chalcopyrite system) ) More preferably as a power generation layer, a Cu-III-VI2 semiconductor power generation layer using Cu as a group I element, particularly a CIS semiconductor [CuIn (Se1-ySy) 2; 0 ≦ y ≦ 1] layer In addition, it is desirable to use a CIGS-based semiconductor [Cu (In1-xGax) (Se1-ySy) 2; 0 <x <1, 0 ≦ y ≦ 1] layer.
Even when a dye-sensitized power generation layer composed of a titanium oxide layer, an electrolyte layer, or the like is employed as the power generation layer, a photoelectric conversion layer with high power generation efficiency can be realized.

As the power generation layer, an organic semiconductor layer (a layer including a p-type semiconductor and an n-type semiconductor) can be employed. In addition, as a p-type semiconductor which can comprise an organic-semiconductor layer, a purophylline compound such as tetrabenzoporphyrin, tetrabenzocopper porphyrin, tetrabenzozinc porphyrin; a phthalocyanine compound such as phthalocyanine, copper phthalocyanine, zinc phthalocyanine; a polycene of tetracene or pentacene; Examples include oligothiophenes such as sexithiophene and derivatives containing these compounds as a skeleton. Furthermore, examples of p-type semiconductors that can form the organic semiconductor layer include polymers such as polythiophene including poly (3-alkylthiophene), polyfluorene, polyphenylene vinylene, polytriallylamine, polyacetylene, polyaniline, polypyrrole, and the like. .

  In addition, n-type semiconductors that can constitute the organic semiconductor layer include fullerenes (C60, C70, C76); octaaporphyrins; perfluoro compounds of the above p-type semiconductors; Examples thereof include aromatic carboxylic acid anhydrides such as acid diimide, perylene tetracarboxylic acid anhydride, and perylene tetracarboxylic acid diimide, and imide compounds thereof; and derivatives containing these compounds as a skeleton.

Further, as a specific configuration example of the organic semiconductor layer, a bulk heterojunction type having a layer (i layer) in which a p-type semiconductor and an n-type semiconductor are phase-separated in the layer, and a layer (p layer) each including a p-type semiconductor. And a layered type (hetero pn junction type), a Schottky type, and a combination thereof, in which layers containing an n-type semiconductor (n layer) are stacked.
Each electrode of the solar battery cell can be formed using one or more arbitrary materials having conductivity. Examples of the electrode material (electrode constituent material) include metals such as platinum, gold, silver, aluminum, chromium, nickel, copper, titanium, magnesium, calcium, barium, sodium, and alloys thereof; indium oxide and tin oxide Metal oxides such as, or alloys thereof (ITO: indium tin oxide); conductive polymers such as polyaniline, polypyrrole, polythiophene, polyacetylene; acids such as hydrochloric acid, sulfuric acid, sulfonic acid, Containing dopants such as Lewis acids such as FeCl3, halogen atoms such as iodine, metal atoms such as sodium and potassium; conductive particles such as metal particles, carbon black, fullerene and carbon nanotubes in a matrix such as a polymer binder Examples include a dispersed conductive composite material.

This electrode material is preferably a material suitable for collecting holes or electrons. Examples of electrode materials suitable for collecting holes (that is, materials having a high work function) include Au, Ag, Cu, Al, ITO, IZO, and ZnO2. Moreover, Al can be illustrated as an electrode material suitable for electron collection (that is, a material having a low work function).
There is no restriction | limiting in particular also in the formation method of an electrode. Therefore, the electrodes can be formed by a dry process such as vacuum deposition or sputtering, or can be formed by a wet process using a conductive ink or the like. As the conductive ink, an arbitrary one (conductive polymer, metal particle dispersion, etc.) can be used.

Each electrode of the solar battery cell may be substantially the same size as the power generation layer or may be smaller than the power generation layer. However, when the electrode on the light-receiving surface side of the solar battery cell is relatively large (the area is not sufficiently small compared to the power generation layer area), the electrode should be transparent ( The transmissivity of the light having a wavelength (for example, 300 to 1200 nm, preferably 500 to 800 nm) at which the electrode, particularly the power generation layer can be efficiently converted into electric energy, is relatively high (for example, 50% or more). ) Electrode. Examples of transparent electrode materials include oxides such as ITO and IZO (indium oxide-zinc oxide); metal thin films, and the like.
In addition, the thickness of each electrode of the solar battery cell and the thickness of the power generation layer can be determined based on the required output, etc., but if it is too thick, the electrical resistance increases, and if it is too thin, the durability is high. May fall.

[Photoelectric conversion layer substrate]
A photoelectric conversion layer base material is a member in which a photovoltaic cell is formed on one surface thereof as needed. Therefore, it is desired that the photoelectric conversion layer base material has a relatively high mechanical strength, is excellent in weather resistance, heat resistance, water resistance, and the like, and is lightweight. It is also desirable that the photoelectric conversion layer base material has a certain degree of resistance to deformation. On the other hand, if the physical properties (for example, linear expansion coefficient, melting point, etc.) of the formed photovoltaic cell are significantly different, there is a risk of distortion or peeling at the interface after formation.

Therefore, it is preferable to employ a metal foil, a resin film having a melting point of 85 to 350 ° C., and some metal foil / resin film laminates as the photoelectric conversion layer substrate.
Examples of the metal foil that can be used as the photoelectric conversion layer substrate (or a component thereof) include foils made of aluminum, stainless steel, gold, silver, copper, titanium, nickel, iron, and alloys thereof.

  The resin film having a melting point of 85 to 350 ° C includes polyethylene, polypropylene, polystyrene, polyvinyl chloride, polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate, polycarbonate, polyacetal, acrylic resin, polyamide resin, ABS resin, ACS resin. , AES resin, ASA resin, copolymers thereof, fluororesins such as PVF, silicone resin, cellulose, nitrile resin, phenol resin, polyurethane, ionomer, polybutadiene, polybutylene, polymethylpentene, polyvinyl alcohol, polyarylate, polyether Examples thereof include films made of ether ketone, polyether ketone, polyether sulfone and the like. From the viewpoint of productivity of the metal resin composite substrate, the resin is preferably a thermoplastic resin. The resin film used as the power generation element substrate is a film in which inorganic substances such as antimony oxide, antimony hydroxide, barium borate, glass fiber, organic fibers, carbon fibers, etc. are dispersed in the resin as described above. There may be.

  The reason why the melting point of the resin film used as the photoelectric conversion layer substrate (or its constituent elements) is preferably 85 ° C. or higher is that when the melting point is excessively low, the photoelectric conversion is performed under the normal use environment of the solar cell module. This is because the layer base material is deformed and may damage the photoelectric conversion layer. The reason why the resin film preferably has a melting point of 350 ° C. or lower is that, if the melting point is excessively high, the photovoltaic cell has a photoelectric conversion layer base as a result of distortion caused by temperature change at the interface with the photoelectric conversion layer. This is because there is a risk of peeling from the material.

  Accordingly, the melting point of the resin film used as the photoelectric conversion layer substrate (or its constituent elements) is more preferably 100 ° C. or higher, further preferably 120 ° C. or higher, and more preferably 150 ° C. or higher. Particularly preferred is 180 ° C. or higher. The melting point of the resin film is more preferably 300 ° C. or less, further preferably 280 ° C. or less, and particularly preferably 250 ° C. or less.

  The thermal expansion coefficient of the photoelectric conversion layer is not particularly limited, but is preferably 40 ppm / K or less, more preferably 35 ppm / K or less, and particularly preferably 30 ppm / K or less. The measuring method of the thermal expansion coefficient is, for example, according to ASTM D696. When the thermal expansion coefficient exceeds 40 ppm / K, deformation due to temperature change is large, and therefore, it tends to be liable to fail under heating / cooling processes or actual use conditions. On the other hand, the lower limit is not particularly limited, but is usually −5 ppm / K or more, preferably 0 ppm / K or more.

<Back side protective layer>
As the back surface protective layer of the solar cell module of the present invention, a resin (hereinafter sometimes referred to as “resin (B)”) material is preferably used.
Examples of such resins include polycarbonate (PC) resin, polymethyl methacrylate (PMMA), glass epoxy multilayer material, fiber reinforced plastic (FRP), cyclic polyolefin, polystyrene, polyethylene terephthalate (PET), and polyethylene naphthalate (PEN). ), Polyimide (PI), ethylene-tetrafluoroethylene copolymer (ETFE), and the like. Preferred examples include polycarbonate (PC) resin, polymethyl methacrylate (PMMA), glass epoxy multilayer material, polyethylene terephthalate (PET), and ethylene-tetrafluoroethylene copolymer (ETFE). The back surface protective layer may have a multilayer structure using a plurality of these resins. In that case, it is preferable to provide a sealing material layer between the layers.

  As resin (B) used for a back surface protective layer, the same kind as resin (A) may be different, but it is preferable to use the same resin. As a combination of the resin (A) and the resin (B), when the resin (A) is a PC resin and the resin (B) is a PC resin, the resin (A) is a PMMA resin and the resin (B) is PMMA. If resin (A) is PC resin and resin (B) is PMMA resin, resin (A) is PMMA resin and resin (B) is PC resin, resin (A) is resin When the resin is an ETFE resin and the resin (B) is an ETFE resin, it is preferable that the resin (A) is an ETFE resin and the resin (B) is a PET resin. A particularly preferable combination is a case where the resin (A) is a PC resin and the resin (B) is a PC resin when a photovoltaic cell such as a polycrystalline silicon cell or a single crystal silicon cell is used for the photoelectric conversion layer. Yes, when using photovoltaic cells such as photoelectric conversion layer amorphous silicon cells, microcrystalline silicon cells, compound solar cells such as CIGS, organic thin film solar cells, dye-sensitized solar cells, resin (A) Is an ETFE resin and the resin (B) is a PET resin, and the effect of the configuration of the present invention becomes remarkable.

  The thickness of the resin (B) is usually 0.1 mm or more when a photovoltaic cell such as a polycrystalline silicon cell or a single crystal silicon cell is used for the photoelectric conversion layer. The thickness is preferably more than 0.5 mm, more preferably 1.0 mm or more, and even more preferably 1.5 mm or more. If it is less than 0.1 mm, the impact resistance is remarkably lowered. On the other hand, the upper limit is not particularly limited, but is preferably 5 mm or less. If the resin becomes too thick, the flexibility of the resin layer is reduced and the weight of the module is increased, so that the merit of using the solar cell module substrate as the resin is lost.

  When using photovoltaic cells such as amorphous silicon cells, microcrystalline silicon cells, compound solar cells such as CIGS, organic thin film solar cells, and dye-sensitized solar cells for the photoelectric conversion layer, usually 0.01 mm or more It is. The thickness is preferably more than 0.02 mm, more preferably 0.05 mm or more, and still more preferably 0.1 mm or more. If it is less than 0.01 mm, impact resistance and tear strength are significantly reduced. On the other hand, the upper limit is not particularly limited, but is preferably 5 mm or less. If the resin becomes too thick, the flexibility of the resin layer is reduced and the weight of the module is increased, so that the merit of using the solar cell module substrate as the resin is lost.

  Further, in order to balance the rigidity of the front and back protective layers so that it is difficult to apply a load to the photoelectric conversion layer, the thickness of the resin (B) is preferably the same as that of the resin (A). The thickness is more preferably in the range of 0.2 to 5 times, more preferably in the range of 0.3 to 3 times, and still more preferably in the range of 0.5 to 2 times.

<Reinforcing layer>
In the solar cell module of the present invention, the reinforcing layer is a layer disposed between the surface protective layer and the back surface protective layer, and is caused by heat shrinkage stress from the surface protective layer and the back surface protective layer generated during cooling after thermal lamination. It is a layer which has a function which prevents that the photovoltaic cell of a photoelectric converting layer is damaged, or a crack arises in a photovoltaic cell.

The number of reinforcing layers included in the solar cell module of the present invention is not particularly limited, but is usually 1 to 2 layers. In addition, at least one of the reinforcing layers is between the surface protective layer and the photoelectric conversion layer, but is preferably between the photoelectric conversion layer and the back surface protective layer.
In the reinforcing layer of the present invention, the area of the laminated surface (the area of the surface perpendicular to the thickness direction) is preferably larger than the area of the laminated surface of the photoelectric conversion layer. By setting it as such an aspect, buckling of the current collection line which exists in the peripheral part of a photoelectric converting layer can be suppressed. Moreover, it is preferable that it is smaller than the area of the laminated surface of a surface protective layer and a back surface protective layer. The reason is that the resins are laminated on the peripheral edge of the solar cell module, and the occurrence of peeling from the end of the reinforcing layer can be suppressed.

  The material of the reinforcing layer is not particularly limited as long as it has optical transparency, and examples thereof include thin plate glass, high-strength plastic (stretched polyethylene terephthalate (stretched PET), stretched polyethylene naphthalate (stretched PEN)), and the like. . Moreover, when arrange | positioning a reinforcement layer in the light-receiving surface side rather than a photoelectric converting layer, it is necessary to use a material with high light transmittance. Examples of such materials include glass, stretched PET, stretched PEN, and thin float glass.

The thickness of the reinforcing layer is not particularly limited, but is usually 10 μm or more, preferably 50 μm or more, and more preferably 100 μm or more. On the other hand, the upper limit is usually 1000 μm or less, preferably 500 μm or less.
In the solar cell module of the present invention, the reinforcing layer is decorated. That is, when the material of the reinforcing layer is transparent or light transmissive, the surface is decorated by printing, painting, vacuum deposition, coloring, or the like. When the reinforcing layer is sealed between the photoelectric conversion layer and the surface protective layer in the solar cell module, the proportion of the decoration on the surface of the reinforcing layer is such that the light receiving surface of the solar cell included in the photoelectric conversion layer is decorated. It is preferable to decorate so that the power generation efficiency is not significantly lowered by the pattern. It is because there is a possibility that sufficient power generation efficiency may not be obtained when the solar battery cells are covered by 30% or more by the decorative pattern.

  In addition, the decorative pattern on the surface of the reinforcing layer is decorated with a pattern in which electric wires (interconnectors, current collectors, ribbon wires, tab wires, bus bars, etc.) connecting the photovoltaic cells of the photoelectric conversion layer are wired. It is preferable. It is because sunlight can fully suppress that it reflects on the metal of an electric wire. If the pattern of the wiring connecting the photovoltaic cells of the photoelectric conversion layer is determined in advance, and the sheet is decorated in advance before manufacturing the solar cell module according to the pattern, the decorative sheet is used as the reinforcing layer. Can be used. The pattern to be decorated is preferably a pattern that can block sunlight with a single color. Examples of the decoration color include black, purple, and red. You may select the color of a decoration according to the color of the photovoltaic cell of a photoelectric converting layer.

  When the reinforcing layer is provided between the photoelectric conversion layer that is not the light receiving surface and the back surface protective layer, the design of the entire solar cell module viewed from the back surface protective layer may be impaired. You may decorate a pattern, ie, the whole surface of the front and back of the reinforcement layer.

<Encapsulant layer>
The solar cell module of the present invention is formed by sealing the reinforcing layer and the photoelectric conversion layer. When these are sealed, a sealing material is present so as to cover the photoelectric conversion layer and the reinforcing layer. Since a sealing material is used so that a photoelectric converting layer may be covered, the layer by a sealing material is formed between a surface protective layer and a photoelectric converting layer, and between a back surface protective layer and a photoelectric converting layer. Moreover, a sealing material layer is formed also when providing a reinforcement layer between a reinforcement layer and a surface protective layer, or between a photoelectric converting layer and a back surface protective layer.

  The sealing material is used to integrate the constituent layers (surface protective layer, photoelectric conversion layer, back surface protective layer, insulating layer, damage prevention layer, etc.) of the solar cell module and reinforce the photoelectric conversion layer. It is a component. Since the photoelectric conversion layer is thinner and weaker than the surface protective layer and the back surface protective layer, the strength of the solar cell module tends to be weak, but the strength can be kept high by the sealing material.

In addition, the sealing material is preferably high in strength from the viewpoint of maintaining the strength of the solar cell module. Specifically, the sealing material is generally related to the strength of the surface protective layer and the back surface protective layer other than the sealing material. However, it is desirable that the entire solar cell module has good durability and has a strength that does not cause internal peeling even after long-term use.
Further, the sealing material is preferably one that transmits visible light from the viewpoint of not hindering light absorption of the photoelectric conversion layer. For example, the transmittance of visible light (wavelength 360 to 830 nm) is usually 60% or more, preferably 70% or more, more preferably 75% or more, still more preferably 80% or more, and particularly preferably 85% or more. Preferably it is 90% or more, Especially preferably, it is 95% or more, Especially preferably, it is 97% or more. This is to convert more sunlight into electrical energy.

  Furthermore, since the solar cell module is often heated by receiving light, it is preferable that the sealing material also has heat resistance. From this viewpoint, the melting point of the constituent material of the sealing material is usually 80 ° C. or higher, preferably 100 ° C. or higher, more preferably 120 ° C. or higher, and usually 350 ° C. or lower, preferably 320 ° C. or lower, more preferably It is 300 degrees C or less. By increasing the melting point, it is possible to reduce the possibility of the sealing material melting and deteriorating when the solar cell module is used.

  As a material which comprises a sealing material, what used the ethylene-vinyl acetate copolymer (EVA) resin composition for the film (EVA film) etc. can be used, for example. In order to improve weather resistance, the EVA film is usually blended with a crosslinking agent to form a crosslinked structure. As the crosslinking agent, an organic peroxide that generates radicals at 100 ° C. or higher is generally used. Examples of such an organic peroxide include 2,5-dimethylhexane; 2,5-dihydroperoxide; 2,5-dimethyl-2,5-di (t-butylperoxy) hexane; Di-t-butyl peroxide or the like can be used. The compounding amount of these organic peroxides is usually 5 parts by weight or less, preferably 3 parts by weight or less, and usually 1 part by weight or more with respect to 100 parts by weight of the EVA resin. In addition, 1 type may be used for a crosslinking agent and it may use 2 or more types together by arbitrary combinations and a ratio.

  This EVA resin composition may contain a silane coupling agent for the purpose of improving the adhesive strength. Examples of the silane coupling agent used for this purpose include γ-chloropropyltrimethoxysilane; vinyltrichlorosilane; vinyltriethoxysilane; vinyl-tri- (β-methoxyethoxy) silane; γ-methacryloxypropyltri Methoxysilane; β- (3,4-ethoxycyclohexyl) ethyltrimethoxysilane and the like can be mentioned. The compounding amount of these silane coupling agents is usually 5 parts by weight or less, preferably 2 parts by weight or less, and usually 0.1 parts by weight or more with respect to 100 parts by weight of the EVA resin. In addition, 1 type may be used for a silane coupling agent and it may use 2 or more types together by arbitrary combinations and a ratio.

  Furthermore, in order to improve the gel fraction of the EVA resin and improve the durability, a crosslinking aid may be included in the EVA resin composition. Examples of the crosslinking aid provided for this purpose include monofunctional crosslinking aids such as trifunctional crosslinking aids such as triallyl isocyanurate and triallyl isocyanate. The amount of these crosslinking aids is usually 10 parts by weight or less, preferably 5 parts by weight or less, and usually 1 part by weight or more with respect to 100 parts by weight of the EVA resin. In addition, 1 type may be used for a crosslinking adjuvant, and 2 or more types may be used together by arbitrary combinations and a ratio.

Furthermore, for the purpose of improving the stability of the EVA resin, the EVA resin composition may contain, for example, hydroquinone; hydroquinone monomethyl ether; p-benzoquinone; methyl hydroquinone. These compounding quantities are normally 5 weight part or less with respect to 100 weight part of EVA resin.

However, since the EVA resin cross-linking process requires a relatively long time of about 1 to 2 hours, it may cause a reduction in the production rate and production efficiency of the solar cell module. In addition, when used for a long period of time, the decomposition gas (acetic acid gas) of the EVA resin composition or the vinyl acetate group of the EVA resin itself may adversely affect the photoelectric conversion layer and reduce the power generation efficiency. Therefore, as the sealing material, a copolymer film made of a propylene / ethylene / α-olefin copolymer can be used in addition to the EVA film. As this copolymer, the thermoplastic resin composition with which the following component 1 and the component 2 were mix | blended is mentioned, for example.
Component 1: The propylene-based polymer is usually 0 part by weight or more, preferably 10 parts by weight or more, and usually 70 parts by weight or less, preferably 50 parts by weight or less.
-Component 2: A soft propylene-type copolymer is 30 weight part or more, Preferably it is 50 weight part or more, and is 100 weight part or less normally, Preferably it is 90 weight part or less.

The total amount of component 1 and component 2 is 100 parts by weight. As described above, when component 1 and component 2 are in a preferred range, the moldability of the encapsulant into a sheet is good, and the resulting encapsulant has good heat resistance, transparency and flexibility, It is suitable for a solar cell module.
Hereinafter, component 1 and component 2 will be described in detail.

[Component 1]
Component 1 is a propylene-based polymer, and examples thereof include a propylene homopolymer; a copolymer of propylene and at least one α-olefin having 2 to 20 carbon atoms other than propylene. Here, as the α-olefin having 2 to 20 carbon atoms other than propylene, for example, ethylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, 1-octene, Examples include decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, 1-eicocene. Among these, ethylene or an α-olefin having 4 to 10 carbon atoms is preferable. In addition, alpha-olefin may use 1 type and may use 2 or more types together by arbitrary combinations and a ratio.

These α-olefins may form a random copolymer with propylene or a block copolymer. The proportion of the constituent units derived from these α-olefins is usually 35 mol% or less, preferably 30 mol% or less in the polypropylene.
Component 1 has a melt flow rate (MFR) measured at 230 ° C. and a load of 2.16 kg in accordance with ASTM D 1238, usually 0.01 g / 10 min or more, preferably 0.05 g / 10 min or more. Usually, it is 1000 g / 10 min or less, preferably 100 g / 10 min or less.

The melting point observed by the differential scanning calorimeter of component 1 is usually 100 ° C. or higher, preferably 110 ° C. or higher, and is usually 160 ° C. or lower, preferably 150 ° C. or lower.
Component 1 can use either an isotactic structure or a syndiotactic structure, but the isotactic structure is preferred in terms of heat resistance and the like.
Further, as the component 1, a plurality of propylene-based polymers can be used in combination as necessary. For example, two or more types of components having different melting points and rigidity can be used.

[Component 2]
Component 2 is a soft propylene-based copolymer, and examples thereof include a copolymer of propylene and at least one α-olefin having 2 to 20 carbon atoms other than propylene.
Component 2 has a Shore A hardness of usually 30 or more, preferably 35 or more, and usually 80 or less, preferably 70 or less.

Furthermore, the melting point observed with the differential scanning calorimeter DSC of component 2 is less than 100 ° C. or no melting point is observed. Here, that the melting point is not observed means that a crystal melting peak having a heat of crystal melting of 1 J / g or more is not observed in the range of −150 to 200 ° C.
In Component 2, the α-olefin used as a comonomer is preferably, for example, ethylene and / or an α-olefin having 4 to 20 carbon atoms. In addition, alpha-olefin may use 1 type and may use 2 or more types together by arbitrary combinations and a ratio.

Component 2 contains propylene-derived units usually 45 mol% or more, preferably 56 mol% or more, and usually 92 mol% or less, preferably 90 mol% or less, and usually contains α-olefin-derived units used as a comonomer. 8 mol% or more, preferably 10 mol% or more, and usually 55 mol% or less, preferably 44 mol% or less.
Component 2 has a melt flow rate (MFR) measured at 230 ° C. and a load of 2.16 kg, usually 0.01 g / 10 min or more, preferably 0.05 g / 10 min or more, in accordance with ASTM D 1238. In addition, it is usually 100 g / 10 min or less, preferably 50 g / 10 min or less.

  Component 2 is based on JIS K6301, using a JIS No. 3 dumbbell, span: 30 mm, tensile speed: 30 mm / min, measured at 23 ° C., stress at 100% strain (M100) is usually 4 MPa. Hereinafter, it is preferably 3 MPa or less, more preferably 2 MPa or less. When the soft propylene copolymer is in such a range, the flexibility, transparency, and rubber elasticity are excellent.

Component 2 has a crystallinity measured by X-ray diffraction of usually 20% or less, preferably 15% or less, and usually 0% or more.
Component 2 has a single glass transition temperature Tg, and the glass transition temperature Tg measured by a differential scanning calorimeter (DSC) is usually in the range of −10 ° C. or lower, preferably −15 ° C. or lower. Is desirable. When the glass transition temperature Tg of Component 2 is within the above range, the cold resistance and low temperature characteristics are excellent.

The molecular weight distribution (Mw / Mn, polystyrene conversion, Mw: weight average molecular weight, Mn: number average molecular weight) measured by GPC of Component 2 is preferably 4.0 or less, more preferably 3.0 or less, and further Preferably it is 2.5 or less.
Preferred specific examples of component 2 include the following propylene / ethylene / α-olefin copolymers. By using such a propylene / ethylene / α-olefin copolymer, a sealing material having good flexibility, heat resistance, mechanical strength, solar cell sealing property and transparency can be obtained. Here, solar cell sealing property means that the cracking rate of the cell at the time of filling a photoelectric converting layer can be reduced by favorable softness | flexibility.

  As propylene / ethylene / α-olefin copolymer, propylene-derived structural units are usually 45 mol% or more, preferably 56 mol% or more, more preferably 61 mol% or more, and usually 92 mol% or less, preferably 90 mol% or less, more preferably 86 mol% or less, and further ethylene-derived structural units are usually 5 mol% or more, preferably 8 mol% or more, and usually 25 mol% or less, preferably 14 mol% or less, more Preferably, it contains 14 mol% or less, and the structural unit derived from an α-olefin having 4 to 20 carbon atoms is usually 3 mol% or more, preferably 5 mol% or more, more preferably 6 mol% or more, and usually 30 mol% or less. , Preferably those containing 25 mol% or less. With regard to α-olefins, 1-butene is particularly preferred.

A propylene / ethylene / α-olefin copolymer (component 2) containing a propylene-derived structural unit, an ethylene-derived structural unit, and a structural unit derived from an α-olefin having 4 to 20 carbon atoms in the above amount is propylene. The compatibility with the system polymer (component 1) becomes good, and the obtained sealing material exhibits sufficient transparency, flexibility, heat resistance and scratch resistance.
The thermoplastic resin composition in which the above component 1 and component 2 are blended has a melt flow rate (ASTM D 1238, 230 degrees, load 2.16 kg) of usually 0.0001 g / 10 min or more. It is 1000 g / 10 min or less, preferably 900 g / 10 min or less, more preferably 800 g / 10 min or less.

The melting point of the thermoplastic resin composition containing component 1 and component 2 is usually 100 ° C. or higher, preferably 110 ° C. or higher. Moreover, it is 140 degrees C or less normally, Preferably it is 135 degrees C or less.
Density of The thermoplastic resin composition Components 1 and 2 were compounded is preferably from 0.98 g / cm ³ or less, more preferably 0.95 g / cm ³ or less, more preferably 0.94 g / cm ³ or less .

In this encapsulant, a coupling agent can be blended into the component 1 and component 2 as an adhesion promoter for plastics and the like. As the coupling agent, silane, titanate, and chromium coupling agents are preferably used, and a silane coupling agent (silane coupling agent) is particularly preferably used.
Known silane coupling agents can be used and are not particularly limited. For example, vinyltriethoxysilane, vinyltrimethoxysilane, vinyltris (β-methoxy-ethoxysilane), γ-glycidoxypropyl-tri Examples include piltrimethoxysilane and γ-aminopropyltriethoxysilane. In addition, 1 type may be used for a coupling agent and it may use 2 or more types together by arbitrary combinations and a ratio.

These are usually 0.1 parts by weight or more, usually 5 parts by weight or less, preferably 100 parts by weight of the silane coupling agent, based on 100 parts by weight of the thermoplastic resin composition (total amount of Component 1 and Component 2). It is desirable to contain 3 parts by weight or less.
The coupling agent may be grafted to the thermoplastic resin composition using an organic peroxide. In this case, it is desirable that 0.1 to 5 parts by weight of the coupling agent is included with respect to 100 parts by weight of the thermoplastic resin composition (total amount of component 1 and component 2). Even if a silane-grafted thermoplastic resin composition is used, the same or better adhesiveness as that of the silane coupling agent blend can be obtained for glass and plastic.

When the organic peroxide is used, the organic peroxide is usually 0.001 part by weight or more, preferably 0.01 part by weight with respect to 100 parts by weight of the thermoplastic resin composition (total amount of Component 1 and Component 2). Part or more, and usually 5 parts by weight or less, preferably 3 parts by weight or less.
Known organic peroxides can be used and are not particularly limited. Examples thereof include dilauroyl peroxide, 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate, and dibenzoylperoxide. Examples thereof include oxide, t-amylperoxy-2-ethylhexanoate, t-butylperoxy-2-ethylhexanoate, t-butylperoxyisobutyrate, and t-butylperoxymaleic acid. In addition, an organic peroxide may use 1 type and may use 2 or more types together by arbitrary combinations and a ratio.

Moreover, the copolymer which consists of an ethylene-alpha-olefin copolymer can also be used as a sealing material. Examples of the copolymer include a laminate film having a hot tack property of 5 to 25 ° C., which is formed by laminating a resin composition for a sealing material comprising the following components A and B and a substrate.
Component A: ethylene resin.
Component B: a copolymer of ethylene and an α-olefin having the following properties (a) to (d).
(A) The density is 0.86 to 0.935 g / cm ³ .
(B) Melt flow rate (MFR) is 1 to 50 g / 10 min.
(C) There is one peak in the elution curve obtained by temperature rising elution fractionation (TREF); the peak temperature is 100 ° C. or lower.
(D) The integrated elution amount by temperature rising elution fractionation (TREF) is 90% or more at 90 ° C.

(A) Component A (ethylene-based resin)
Examples of the ethylene-based resin as the component A constituting the resin composition for a sealing material include a high-pressure low-density polyethylene, an ethylene / vinyl acetate copolymer, an ethylene / acrylic acid copolymer produced by a so-called radical polymerization method. Examples thereof include an ethylene / acrylic acid ester copolymer and an ethylene / vinyl fluoride copolymer. Moreover, the polymer or copolymer which has ethylene as a main component, such as what is called linear low density polyethylene and high density polyethylene manufactured by the ionic polymerization method, is also mentioned. Among these, ethylene / vinyl acetate copolymer and high pressure method low density polyethylene are preferable. In addition, these may use 1 type and may use 2 or more types together by arbitrary combinations and ratios.
When the ethylene resin as component A constituting the resin composition for a sealing material is an ethylene / vinyl acetate copolymer, those having the following properties are suitable.

(I) Melt flow rate (MFR)
JIS of ethylene / vinyl acetate copolymer as component A constituting resin composition for encapsulant
The MFR (melt flow rate: melt flow rate) by K7210 is usually 1 g / 10 minutes or more, preferably 2 g / 10 minutes or more, more preferably 3 g / 10 minutes or more, and usually 50 g / 10 minutes. Hereinafter, it is preferably 30 g / 10 min or less, more preferably 20 g / 10 min or less. Increasing the MFR tends to increase transparency when blended with the component B, and decreasing the MFR tends to facilitate molding.

(Ii) Vinyl acetate content The vinyl acetate content of the ethylene / vinyl acetate copolymer as component A constituting the resin composition for a sealing material is usually 3% by weight or more, preferably 4% by weight or more, more preferably 5%. It is usually not more than 30% by weight, preferably not more than 20% by weight, more preferably not more than 15% by weight. Increasing the vinyl acetate content tends to increase heat sealability, and reducing the vinyl acetate content can suppress stickiness of the sealing material.
When the ethylene-based resin as component A constituting the resin composition for a sealing material is a high-pressure method low-density polyethylene, those having the following properties are suitable.

(I) Melt flow rate (MFR)
The MFR (melt flow rate: melt flow rate) of JIS K7210 of the high-pressure low-density polyethylene as component A constituting the resin composition for a sealing material is usually 1 g / 10 min or more, preferably 2 g / 10. Min. Or more, more preferably 3 g / 10 min or more, and usually 50 g / 10 min or less, preferably 30 g / 10 min or less, more preferably 20 g / 10 min or less. It tends to be easy to extrude by increasing the MFR, and by reducing the MFR, the film becomes too soft and does not easily sag, and the moldability increases.

(Ii) Density by JIS K7112 of high-pressure low-density polyethylene as component A constituting the density encapsulant resin composition is usually 0.915 g / cm ³ or more, preferably 0.916 g / cm ³ or more, more preferably at 0.917 g / cm ³ or more and usually 0.93 g / cm ³ or less, preferably 0.925 g / cm ³ or less, more preferably 0.923 g / cm ³ or less. Increasing the density tends to suppress stickiness of the sealing material, and decreasing the density tends to increase heat sealability.
As the high-pressure method low-density polyethylene as component A constituting the resin composition for a sealing material, those exhibiting the above physical properties can be appropriately selected from commercially available products.

(B) Component B (ethylene / α-olefin copolymer)
Component B constituting the resin composition for a sealing material is an ethylene / α-olefin copolymer other than Component A. Component B preferably has the following properties.

(I) Density The density according to JlS K7112 of the ethylene / α-olefin copolymer as component B constituting the resin composition for a sealing material is usually 0.86 g / cm ³ or more, preferably 0.87 g /
cm ³ or more, more preferably 0.88 g / cm ³ or more, and usually 0.935 g / cm ³ or less, preferably 0.915 g / cm ³ or less, more preferably 0.91 g / cm ³ or less. By increasing the density, stickiness when used as a film tends to be suppressed, and by decreasing the density, heat sealability tends to increase.

(Ii) Melt flow rate (MFR)
The MFR (melt flow rate: melt flow rate) according to JLS K7210 of the ethylene / α-olefin copolymer as component B constituting the resin composition for a sealing material is usually 1 g / 10 min or more, preferably It is 2 g / 10 min or more, more preferably 3 g / 10 min or more, and is usually 50 g / 10 min or less, preferably 30 g / 10 min or less, more preferably 20 g / 10 min or less. It tends to be easy to extrude by increasing the MFR, and by reducing the MFR, the film becomes too soft and does not easily sag, and the moldability increases.

  Here, the α-olefin is preferably an α-olefin having 4 to 40 carbon atoms. Among them, among α-olefins, those having usually 4 or more, preferably 6 or more, and usually 12 or less, preferably 10 or less are desirable. For example, 1-butene, 1-pentene, 1-hexene, 1-octene, 1-heptene, 4-methylpentene-1, 4-methylhexene-1, 4,4-dimethylpentene-1, etc. Is mentioned. In addition, alpha-olefin may use 1 type and may use 2 or more types together by arbitrary combinations and a ratio.

  The ratio of α-olefin to ethylene is usually 2% by weight or more, preferably 5% by weight or more, more preferably 10% by weight or more, and usually 60% by weight or less, preferably 50% by weight or less. More preferably 30 wt% or less, ethylene is usually 40 wt% or more, preferably 50 wt% or more, more preferably 70 wt% or more, and usually 98 wt% or less, preferably 95 wt% or less, more preferably It is desirable that the content be 90% by weight or less.

  The blending ratio (component A / component B) of component A and component B is usually 50/50 or more, preferably 55/45 or more, more preferably 60/40 or more, and usually 99 / 1 or less, preferably 90/10 or less, more preferably 85/15 or less. Increasing the amount of component B tends to increase transparency and heat sealability, and decreasing the amount of component B tends to increase the workability of the film.

  The melt flow rate (MFR) of the resin composition for a sealing material produced by blending component A and component B is usually 2 g / 10 minutes or more, preferably 3 g / 10 minutes or more, and usually 50 g / 10 minutes. Hereinafter, it is preferably 40 g / 10 min or less. In addition, the measurement and evaluation of MFR can be implemented by the method based on JISK7210 (190 degreeC, 2.16kg load).

The melting point of the encapsulant resin composition is preferably 50 ° C. or higher, more preferably 55 ° C. or higher, and is usually 300 ° C. or lower, preferably 250 ° C. or lower, more preferably 200 ° C. or lower. By increasing the melting point, the possibility of melting and deterioration during use of the solar cell module can be reduced.
The density of the encapsulating resin composition is preferably 0.80 g / cm ³ or more, more preferably 0.85 g / cm ³ or more, and preferably 0.98 g / cm ³ or less, 0.95 g / cm ^3. The following is more preferable, and 0.94 g / cm ³ or less is more preferable. The measurement and evaluation of density can be performed by a method based on JIS K7112.

Further, in the sealing material using the ethylene / α-olefin copolymer, a coupling agent can be used in the same manner as in the case of using the propylene / ethylene / α-olefin copolymer.
Since the sealing material described above does not generate a decomposition gas derived from the material, it does not adversely affect the photoelectric conversion layer, and has good heat resistance, mechanical strength, flexibility (solar cell sealing property) and transparency. Have. In addition, since a material cross-linking step is not required, the manufacturing time of the sheet molding and the solar cell module can be greatly shortened, and the solar cell module after use can be easily recycled.

Note that the sealing material layer may be formed of one kind of material or two or more kinds of materials. Moreover, although the sealing material may be formed with the single layer film, the laminated | multilayer film provided with the film of two or more layers may be sufficient as it.
In the present invention, as described above, ethylene-vinyl acetate copolymer, copolymer made of propylene / ethylene / α-olefin copolymer, copolymer made of ethylene / α-olefin copolymer are used as the material of the sealing material. Although coalescence was illustrated preferably, the effect of this invention can be acquired more by using these as a material of a sealing material.

Although there is no restriction | limiting in the position which provides a sealing material layer, Usually, it provides so that a photoelectric converting layer may be inserted | pinched. This is for reliably protecting the photoelectric conversion layer. In this embodiment, sealing materials are provided on the front surface and the back surface of the photoelectric conversion layer, respectively.
The thickness of the sealing material layer is not particularly limited, but is preferably 50 μm or more, more preferably 100 μm or more, further preferably 150 μm or more, and preferably 2000 μm or less, more preferably 1000 μm or less, and still more preferably 800 μm. It is as follows.
By increasing the thickness, mechanical strength tends to increase, and insulation between the photoelectric conversion layer and the substrate can be secured. Thinning tends to increase flexibility and increase light transmittance.

<Method for manufacturing solar cell module>
Although the manufacturing method of the solar cell module of this invention can use a well-known method, for example, the laminated body which laminated | stacked the multilayer sheet containing a surface protective layer, a reinforcement layer, a photoelectric converting layer, a back surface protective layer, and a sealant is vacuumed. A solar cell module can be obtained by placing in a lamination device, heating after vacuuming, and cooling after a predetermined time.

The heat laminating conditions are not particularly limited, and heat laminating is possible under normal conditions.
It is preferably performed under vacuum conditions, and the degree of vacuum is usually 30 Pa or more, preferably 50 Pa or more, more preferably 80 Pa or more. On the other hand, the upper limit is usually 150 Pa or less, preferably 120 Pa or less, more preferably 100 Pa or less. By setting it as the said range, since generation | occurrence | production of a bubble can be suppressed in each layer in a module, and productivity improves, it is preferable.

Although it does not specifically limit as vacuum time, Usually, it is 1 minute or more, Preferably it is 2 minutes or more, More preferably, it is 3 minutes or more. On the other hand, the upper limit is usually 30 minutes or less, preferably 20 minutes or less, more preferably 10 minutes or less. Setting the vacuum time in the above range is preferable because the appearance of the solar cell module after heat lamination becomes good and the generation of bubbles in each layer in the module can be suppressed.

  The pressure condition of the heat laminate is not particularly limited, but the normal pressure is 50 kPa or more, preferably 70 kPa or more, more preferably 90 kPa or more. On the other hand, the upper limit value is 200 kPa or less, preferably 110 kPa or less. By setting it as the pressurization conditions of the said range, since moderate adhesiveness can be acquired, without damaging a solar cell module, it is preferable also from a durable viewpoint.

The pressure holding time is not particularly limited, but is usually 1 minute or longer, preferably 3 minutes or longer, more preferably 5 minutes or longer. On the other hand, the upper limit is usually 120 minutes or less, preferably 900 minutes or less, more preferably 60 minutes or less. By setting the holding time, sufficient adhesive strength can be obtained.
The temperature condition of the heat laminate is not particularly limited, but is usually 100 ° C. or higher, preferably 110 ° C. or higher, more preferably 120 ° C. or higher. On the other hand, the upper limit is usually 180 ° C. or lower, preferably 160 ° C. or lower, more preferably 150 ° C. or lower. By setting the temperature range, sufficient adhesive strength can be obtained.

Moreover, the heating time of the said temperature is although it does not specifically limit, Usually, 5 minutes or more, Preferably it is 10 minutes or more, More preferably, it is 15 minutes or more. On the other hand, the upper limit is 100 minutes or less, preferably 60 minutes or less, more preferably 45 minutes or less. By setting it as the said heating time, since durability of a sealing material is bridge | crosslinked moderately and it can have moderate softness | flexibility, it is preferable.
The solar cell module of the present invention can be installed and used in various places for various applications. In particular, it is preferably used as a solar cell module for a vehicle installed in a vehicle such as a passenger car, a truck, a bus, or a train. It may be installed directly on the vehicle member. For example, it is preferably installed on an instrument panel, a roof, a bonnet, a rear spoiler, a door, and the like.
EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, it cannot be overemphasized that this invention is not limited only to a following example.

<Example 1>
A solar cell module 1 having the layer configuration shown in FIG. 1 was produced.
Specifically, as a back surface protective layer, on a polycarbonate plate (Mitsubishi Plastic Sales Co., Ltd., Stella (registered trademark)) having a length of 680 mm, a width of 570 mm, and a thickness of 2 mm, a length of 680 mm, a width of 570 cm, and a thickness of 0.4 mm A sealing film sheet (produced by C.I. Kasei Co., Ltd., ethylene-vinyl acetate copolymer (EVA) sheet), and a reinforcing layer of 680 mm in length, 570 cm in width, 0.1 mm in thickness, and a PET film decorated with black (Mitsubishi Resin Co., Ltd., Model: T680E), 680 mm long, 570 cm wide, 0.4 mm thick encapsulant sheet (Ci Kasei Co., Ltd., ethylene-vinyl acetate copolymer (EVA) sheet) sequentially Laminated and 12 polycrystalline silicon cells (Q-cells, model: Q6LTT3-200 / 1660-AD; 156 mm square) are stacked on top of each other. Connected with three connectors (lead-free solder-coated copper wire, width 1.3 mm x thickness 0.2 mm) and current collector (lead-free solder-coated copper wire, width 5 mm x thickness 0.18 mm) as shown in Fig. 2 Arranged the connected ones. The distance between adjacent cells was 4 mm both vertically and horizontally. On the photoelectric conversion layer, 680 mm long, 570 mm wide, 0.4 mm thick sealing material sheet (EVA sheet manufactured by CI Kasei Co., Ltd.), 680 mm long, 570 mm wide, 0.1 mm thick PET as a reinforcing layer The film (Mitsubishi Resin Co., Ltd., T680E) was decorated with a black pattern in advance so that the portion where the interconnector (wire) was wired and the cell periphery were covered from the light receiving surface side (upper surface) as shown in FIG. An encapsulant sheet having a length of 680 mm, a width of 570 mm, and a thickness of 0.4 mm (EVA sheet manufactured by C-I Kasei Co., Ltd.) and a polycarbonate plate having a length of 680 mm, a width of 570 mm, and a thickness of 2 mm as a surface protective layer are placed thereon. The laminate on which (Mitsubishi Resin Sales Co., Ltd.) was placed was put into a solar cell module laminator (NPC, LM-50 × 50-S).

First, the inside of the laminator was held under reduced pressure for 5 minutes, and then the laminated body was held at 130 ° C. for 55 minutes while being brought into a pressure-bonded state at atmospheric pressure, whereby the solar cell module 1 was obtained. Thereafter, it was cooled from 130 ° C. to 30 ° C. over 30 minutes. After cooling, when the appearance inspection of the solar cell module 1 was performed, the external appearance was constituted only by the color and black color of the solar battery cells, and the electric wires (silver color) such as the interconnector and the collector line could not be seen. Further, the solar cell was not damaged by the stress change of the polycarbonate resin caused by the temperature change due to the laminate molding by the reinforcing layer, and the interconnector and the current collector were not buckled. The maximum power generation efficiency at the time of irradiation with pseudo-sunlight 1000 w / m ² according to JIS C8991 was 41 W. There was no glare on the surface of the solar cell module due to sunlight.

<Comparative Example 1>
In Example 1, a solar cell module 2 having the layer configuration shown in FIG. 4 was produced in the same manner as in Example 1 except that the PET film of the reinforcing layer was not decorated.
When an appearance inspection of the solar cell module 2 was performed, wires (silver) such as an interconnector and a collecting wire were exposed, and a sense of unity by color was poor and design was low. The maximum power generation efficiency at the time of irradiation of pseudo-sunlight 1000 w / m ² according to JIS C8991 was 43 W. The surface of the solar cell module by sunlight was reflected by the electric wire and glared. Depending on the installation location (especially the vehicle), there is a possibility that human vision may be disturbed, and there is a concern about a reduction in safety.

<Example 2>
The solar cell module 3 according to Example 2 of the present invention has the configuration shown in FIG. And the solar cell module (size: 250 mm x 300 mm) which concerns on Example 2 is manufactured with the following structures and procedures.
As a backside protective layer, a polyolefin film (Dai Nippon Printing Co., Ltd.) with a thickness of 0.4 mm is placed as a sealing material sheet on a colorless and transparent PET film (Toyobo Co., Ltd. model: Q1C15) with a thickness of 0.125 mm. Then, on the polyimide film with a thickness of 50 μm as the photoelectric conversion layer base material, a silver (back surface electrode), an amorphous silicon layer (power generation layer), and a transparent electrode are formed. A photoelectric conversion layer on which is formed was placed (size: 190 mm × 156 mm). As the electric wire for extracting electric power from this cell, one having a thickness of 50 μm and a width of 4 mm (DT101C4 manufactured by Dexerials) was used. And as a sealing material sheet, thickness 0
. A 4 mm polyolefin film (Dai Nippon Printing Co., Ltd.) is placed, and a 0.125 mm thick PET layer as a reinforcing layer is superposed in this order, and the same color as the solar cell (amorphous silicon) on the surface of the PET layer : Red-purple pigment on a decorative pattern as shown in FIG. 6, and UV absorption-gas barrier layer (0.05 mm) on top. As a surface protective layer, an ETFE layer having a thickness of 0.05 mm was placed.

While taking care that the power generation layer portion of the photoelectric conversion layer and the undecorated portion of the composite film coincide with each other, they are laminated to form a laminate, and heated at 110 ° C. using a vacuum laminator manufactured by NPC. Lamination (vacuum degree: 80 Pa, vacuum time: 10 minutes, pressurization: 100 kPa, heating and holding time: 15 minutes) was carried out to produce a solar cell module 3.
After cooling, an appearance inspection of the solar cell module 3 was performed. As a result, the gray portion of the wiring portion or the copper color portion of the wiring member was not visible, and the appearance was configured only with the same color tone as the power generation portion (red purple). Further, the photoelectric conversion layer was not damaged and the current collector was not buckled due to the stress of the ETFE resin caused by the temperature change due to the laminate molding by the reinforcing layer. The maximum power generation efficiency at the time of irradiation with pseudo-sunlight 1000 w / m ² according to JIS C8991 was 2 W. There was no glare on the surface of the solar cell module due to sunlight.

<Example 3>
The solar cell module 4 according to Example 3 of the present invention has the configuration shown in FIG. And the solar cell module (size 250 mm x 300 mm) which concerns on Example 3 is manufactured with the following structures and procedures.
As a backside protective layer, on a colorless and transparent PET film (Q1C15 manufactured by Toyobo Co., Ltd.) with a thickness of 0.125 mm, and as a sealing material sheet, on a polyolefin film (Dai Nippon Printing Co., Ltd.) with a thickness of 0.4 mm The same photoelectric conversion layer as that in Example 2 was placed. A lead-free solder-coated copper wire (manufactured by Hitachi Cable Co., Ltd.) having a thickness of 180 μm and a width of 5 mm was used as a wiring material for taking out electric power from the cell.

A 0.15 mm thick polyolefin film (Dai Nippon Printing Co., Ltd. Z74) is placed on the photoelectric conversion layer as a sealing material sheet, and a 0.1 mm thick PET film (Mitsubishi) is used as a reinforcing layer. Resin Co., Ltd. product, T680E) was decorated in black with a central portion of a sheet that was hollowed out in a rectangular shape (FIG. 8). Next, a polyolefin film (Z74 manufactured by Dai Nippon Printing Co., Ltd.) having a thickness of 0.15 mm was placed as a sealing material sheet, and an ETFE layer having a thickness of 0.05 mm as a surface protective layer, a UV absorption-gas barrier layer (0.05 mm), P with a thickness of 0.125mm
A composite film (“View Barrier” (registered trademark) FDK-3AA, manufactured by Mitsubishi Plastics, Inc.) formed by stacking the ET layers in this order was placed.

While taking care that the power generation layer portion of the photoelectric conversion layer and the undecorated portion of the composite film coincide with each other, they are laminated to form a laminate, and heated at 130 ° C. using a vacuum laminator manufactured by NPC. Lamination (vacuum degree: 80 Pa, vacuum time: 15 minutes, pressurization: 100 kPa, heating and holding time: 30 minutes) was carried out to produce a solar cell module 4.
After cooling, when the appearance inspection of the solar cell module 4 was performed, the gray part of the wiring part or the silver part of the wiring material was not visible, and only the power generation part (dark purple) and the decoration part (black) were configured, and the color tone was in order It was a good appearance. Further, the photoelectric conversion layer was not damaged and the current collector was not buckled due to the stress of the ETFE resin caused by the temperature change due to the laminate molding by the reinforcing layer. The maximum power generation efficiency at the time of irradiation with pseudo-sunlight 1000 w / m ² according to JIS C8991 was 2 W. There was no glare on the surface of the solar cell module due to sunlight.

DESCRIPTION OF SYMBOLS 1 Surface protective layer 2 Back surface protective layer 3 Photoelectric conversion layer 31 Interconnector (electric wire)
4 Sealing material 5 Reinforcing layer (with decoration)
5 'Reinforcement layer (no decoration)
6 Adhesive layer

Claims (5)

Between the surface protective layer and the back surface protective layer, a solar cell module formed by sealing a photoelectric conversion layer including one or more solar cells connected by a reinforcing layer and an electric wire, from the solar light receiving surface side, A solar cell module, wherein a surface protective layer, a reinforcing layer, a photoelectric conversion layer, and a back surface protective layer are laminated in this order, and the reinforcing layer is decorated.   The solar cell module according to claim 1, wherein the reinforcing layer is decorated in a wiring pattern of the electric wire included in the photoelectric conversion layer existing on the sunlight receiving surface side.   The solar cell module according to claim 1, further comprising a reinforcing layer between the photoelectric conversion layer and the back surface protective layer.   The solar cell module according to any one of claims 1 to 3, wherein the material of the reinforcing layer is glass or a stretched polyester resin sheet.   The member for vehicles which has a solar cell module of any one of Claims 1-4.