JP2012216803A - Solar cell module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a solar cell module, using polycarbonate as a substrate, capable of preventing its appearance and adhesion in it from being degraded by suppressing air bubbles from gathering in it during its production.SOLUTION: To provide a solar cell module, formed by layering a weather-resistant layer, a power generation member, a sealing layer, and polycarbonate substrate in this order, includes a buffer layer between the sealing layer and the polycarbonate substrate. The buffer layer include a layer with Young's modulus of at least 1 MPa.

Description

  The present invention relates to a solar cell module.

  In recent years, people's awareness of ecology has increased, and expectations for solar cells, which are clean energy, are increasing due to their safety and ease of handling. As a specific example of such a solar cell, a see-through solar cell module having a light transmission part is known (Patent Document 1).

The see-through solar cell module described in Patent Document 1 includes a surface covering material, a solar cell element, a back surface covering material, a sealing layer for embedding the solar cell element, and the like.
Patent Document 1 describes an example in which polycarbonate is used as the surface covering material or the back surface covering material, and EVA (vinyl acetate-ethylene copolymer) is used as the material of the sealing layer.

  The solar cell module proposed in Patent Document 1 is manufactured by laminating EVA, a solar cell element, and the like as a sealing layer on polycarbonate, which is a back surface covering material, and this lamination is performed by thermal lamination. .

JP-A-9-92848

In the solar cell module proposed in Patent Document 1, polycarbonate is used as a covering material for the back surface and the front surface. According to the study by the present inventors, since polycarbonate has a property of easily absorbing moisture, bubbles are easily generated in the solar cell module due to heat applied during thermal lamination. In addition, due to heat shrinkage of the polycarbonate, distortion occurs between the coating material and the sealing layer, and an extra space is generated at the interface, so that bubbles generated in the space may accumulate. Due to the presence of such bubbles, the adhesive force between the covering material and the sealing layer may be reduced, or the appearance of the solar cell module may be impaired.
The present invention solves the above-mentioned problems, and in a solar cell module using polycarbonate as a base material, the appearance and the solar cell can be reduced by suppressing the accumulation of bubbles in the solar cell module during the production of the solar cell module. Ensure that the adhesion within the module is not compromised.

The inventors of the present invention have made extensive studies to solve the above problems, and in a solar cell module using polycarbonate as a base material, the buffer layer is provided between the sealing layer and the polycarbonate base material to solve the above problem. The present invention has been completed by conceiving what can be done.
The present invention is a solar cell module in which a weathering layer, a power generation member, a sealing layer, and a polycarbonate substrate are laminated in this order, and a buffer layer is provided between the sealing layer and the polycarbonate substrate. And the buffer layer includes a layer having a Young's modulus of 1 MPa or more.

Moreover, it is a preferable aspect that the said buffer layer contains the layer which has the following physical property of (1) and (2).
(1) Tg: 0 to 200 ° C
(2) Young's modulus: 300 to 3000 MPa

  Moreover, it is a preferable aspect that the said buffer layer contains the layer whose Tm is 100 degreeC or more. Moreover, it is a preferable aspect that the said buffer layer consists of 1 or more materials selected from the group which consists of a fluororesin, polyester, glass, and polyolefin.

  Moreover, it is a preferable aspect that an adhesive layer is further provided between the buffer layer and the polycarbonate substrate.

  In a preferred embodiment, the adhesive layer is made of one or more materials selected from the group consisting of an ethylene-vinyl acetate copolymer, a urethane resin, and an acrylic resin.

  According to the present invention, it is possible to provide a solar cell module in which appearance and adhesion within the solar cell module are not impaired by suppressing air bubbles from being accumulated in the solar cell module when the solar cell module is manufactured.

It is a schematic diagram of one embodiment of the solar cell module of the present invention.

  The solar cell module of the present invention is a solar cell module in which a weathering layer, a power generation member, a sealing layer, and a polycarbonate base material are laminated in this order, and between the power generation member and the polycarbonate base material. It has a buffer layer.

<Polycarbonate substrate>
About the polycarbonate used as a base material which comprises the solar cell module of this invention, what is normally used in this technical field can be used. By using polycarbonate as the base material of the solar cell module, the solar cell module can be made resistant to impact and lightweight.

The thickness of the polycarbonate substrate used in the present invention is usually 0.5 mm or more, preferably 0.7 mm or more, more preferably 1.0 mm or more, and 1.2 mm or more. Particularly preferred. By setting it as such thickness, sufficient intensity | strength can be provided to a solar cell module.
The thickness of the polycarbonate substrate used in the present invention is preferably 30% or more of the total thickness of the solar cell module, more preferably 40% or more, and particularly preferably 50% or more. On the other hand, the thickness of the polycarbonate substrate is preferably 90% or less of the total thickness of the solar cell module, more preferably 80% or less, and particularly preferably 75% or less. In such a range, the strength of the solar cell module can be maintained appropriately, and the warping of the polycarbonate substrate due to thermal lamination is alleviated and the peeling of each layer accompanying the deformation of the polycarbonate substrate in the usage environment is suppressed. It becomes possible to do.

<Buffer layer>
In the solar cell module of the present invention, a buffer layer is laminated between the sealing layer and the polycarbonate substrate. The buffer layer in the present invention has a function of absorbing the strain in the solar cell module that is generated when heat is applied to the solar cell module, and also allowing the gas generated at that time to escape to the outside of the solar cell module. Say. When such a buffer layer is present between the sealing layer and the polycarbonate substrate, it is possible to suppress the accumulation of bubbles in the solar cell module.

The buffer layer constituting the solar cell module of the present invention includes a layer having a Young's modulus of 1 MPa or more in order to perform the above function. It is preferable to include a layer having the following physical properties (1) and (2), and to include a layer having the physical properties (3) and / or (4) in addition to the physical properties (1) and (2). Is more preferable.
Among them, the layer having the following physical properties (1) and (2) is preferable, and in addition to the physical properties (1) and (2), the layer also has the physical properties (3) and / or (4). Preferably it consists of.

(1) Glass transition point (Tg)
The glass transition point (Tg) of the buffer layer is preferably 0 ° C. or higher, more preferably 20 ° C. or higher, and particularly preferably 50 ° C. or higher. On the other hand, the glass transition point (Tg) of the buffer layer is usually 600 ° C. or lower, preferably 300 ° C. or lower, more preferably 200 ° C. or lower, still more preferably 150 ° C. or lower, A temperature of 130 ° C. or lower is particularly preferable.
When the glass transition point of the buffer layer constituting the solar cell module of the present invention is in the above range, strain due to thermal contraction of the polycarbonate base material can be better absorbed.
On the other hand, it is preferable that the glass transition point (Tg) is 0 ° C. or higher because wrinkles are hardly generated in the entire solar cell module. In particular, when the temperature is 200 ° C. or lower, bubbles are less likely to be generated at the buffer layer / sealing layer interface.

(2) Young's modulus Moreover, the buffer layer includes a layer having a Young's modulus of 1 MPa or more so that the buffer layer can more easily absorb strain due to thermal shrinkage of the polycarbonate substrate. The Young's modulus of the layer included in the buffer layer is preferably 10 MPa or more, more preferably 100 MPa or more, further preferably 200 MPa or more, and particularly preferably 400 MPa or more. On the other hand, the Young's modulus of the layer included in the buffer layer is preferably 3000 MPa or less, more preferably 2000 MPa or less, and particularly preferably 1000 MPa or less.
The ratio of the layer having a Young's modulus of 1 MPa or more in the buffer layer is not particularly limited as long as the effect of the present invention is obtained, but is preferably 5% or more in the total thickness of the buffer layer, It is more preferably 10% or more, further preferably 50% or more, particularly preferably 80% or more, and most preferably 100%.
It is preferable that the buffer layer includes a layer having a Young's modulus of 1 MPa or more, more preferably 10 MPa or more, and even more preferably 100 MPa or more because wrinkles are not easily generated in the entire solar cell module. Moreover, when a layer of 3000 MPa or less is included, bubbles are less likely to be generated at the buffer layer / sealing layer interface.
Among them, the Young's modulus of the buffer layer is preferably 1 MPa or more, more preferably 10 MPa or more, further preferably 100 MPa or more, particularly preferably 200 MPa or more, and most preferably 400 MPa or more. preferable. On the other hand, the Young's modulus of the buffer layer is preferably 3000 MPa or less, more preferably 2000 MPa or less, and particularly preferably 1000 MPa or less.
The Young's modulus of the buffer layer can be adjusted by changing the type and composition ratio of the material used for the buffer layer.
The Young's modulus is a value measured according to the JIS-K7161 tensile test. For the measurement, a single column type tensile compression tester manufactured by A & D was used.

(3) Melting point (Tm)
The melting point (Tm) of the buffer layer is usually 100 ° C. or higher, preferably 130 ° C. or higher, more preferably 150 ° C. or higher, still more preferably 180 ° C. or higher, and 200 ° C. or higher. It is particularly preferred. On the other hand, the melting point (Tm) of the buffer layer is usually 1500 ° C. or lower, preferably 350 ° C. or lower, more preferably 300 ° C. or lower, and particularly preferably 280 ° C. or lower.
When the melting point of the buffer layer constituting the solar cell module of the present invention is in the above range, the strain due to the heat shrinkage of the polycarbonate base material can be better absorbed.
On the other hand, it is preferable that the melting point (Tm) is 150 ° C. or higher because wrinkles are hardly generated in the entire solar cell module. In particular, when the temperature is 300 ° C. or lower, bubbles are hardly generated at the buffer layer / sealing layer interface.

The Tg and Tm of the buffer layer can be adjusted by changing the type and composition ratio of the material used for the buffer layer.
The glass transition point (Tg) and the melting point (Tm) can be determined according to JIS K 7121 by differential scanning calorimetry (DSC).

(4) Gas permeability The buffer layer in the present invention preferably has a gas permeability of 100 g / m ² / day or less, and more preferably 50 g / m ² / day or less. The lower limit is preferably as low as possible, but is usually 10 ⁻¹⁰ g / m ² / day or more, preferably 10 ⁻⁸ g / m ² / day or more, more preferably 10 ⁻⁴ g / m ² / day or more. Preferably, it is 10 ⁻³ g / m ² / day or more.
The gas permeability referred to in the present application is obtained using water vapor as a gas, and the value thereof is, for example, JIS-K7129 using (Lyssy L80-5000 type water vapor permeability meter).
It can be determined according to
When the gas permeability of the buffer layer is in the above range, when the solar cell module is heat laminated or when heat is applied to the solar cell module, the gas generated in the module does not stay inside, Will be released. Thereby, it is preferable that bubbles do not accumulate in the solar cell module.
The gas permeability of the buffer layer can be adjusted by changing the type and composition ratio of the material used for the buffer layer.

In addition, the linear expansion coefficient (MD: flow direction) of the buffer layer is usually 1 ppm / K or more, and 10 ppm / K or more so that the buffer layer can more easily absorb strain due to heat shrinkage of the polycarbonate substrate. It is preferably at least 30 ppm / K, more preferably at least 50 ppm / K. On the other hand, the linear expansion coefficient (MD: flow direction) of the buffer layer is preferably 4000 ppm / K or less, more preferably 3000 ppm / K or less, and particularly preferably 2000 ppm / K or less.
A linear expansion coefficient (MD: flow direction) of 1 ppm / K or more is preferable because wrinkles are not easily generated in the entire module. In particular, when it is 4000 ppm / K or less, bubbles are hardly generated at the buffer layer / sealing layer interface.
Furthermore, the linear expansion coefficient (TD: perpendicular direction) of the buffer layer is usually 1 ppm / K or more, preferably 10 ppm / K or more, more preferably 30 ppm / K or more, and 50 ppm / K or more. It is particularly preferred. On the other hand, the linear expansion coefficient (TD: perpendicular direction) of the buffer layer is preferably 4000 ppm / K or less, more preferably 3000 ppm / K or less, and particularly preferably 2000 ppm / K or less.
A linear expansion coefficient (TD: perpendicular direction) of 1 ppm / K or more is preferable because wrinkles are not easily generated in the entire module. Moreover, especially when it exceeds 4000 ppm / K, it becomes difficult to produce bubbles at the buffer layer / sealing layer interface.
The linear expansion coefficient of the buffer layer can be adjusted by changing the type and composition ratio of the material used for the buffer layer.
The linear expansion coefficient can be measured in accordance with, for example, JIS K 7197 for both MD and TD.

The buffer layer of the present invention absorbs strain in the solar cell module that is generated when heat is applied to the solar cell module, and has a function of letting the gas generated at that time escape to the outside of the solar cell module. If there is, it can be used as a material without any particular limitation.
Among the materials that can be used, fluorine resin, polyester resin, glass and polyolefin resin can be preferably exemplified as those having the above-mentioned functions, among which fluorine resin, polyester resin and glass are preferable, and fluorine resin and polyester resin are particularly preferable. Illustrated.
Specific examples of the fluororesin include perfluoroalkoxy fluororesin (PFA), ethylene tetrafluoride-hexafluoropropylene copolymer (FEP), ethylene-tetrafluoroethylene copolymer (ETFE), and ethylene-chlorotrifluoro. Ethylene copolymer (ECTFE)
Preferred examples include fluorinated resin copolymers. Among these, it is particularly preferable to use an ethylene-tetrafluoroethylene copolymer (ETFE).

Specific examples of the polyester resin include, for example, polyethylene terephthalate (PET), polytrimethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate (PEN), and polybutylene naphthalate in the above ranges of Tg, Tm, linear expansion coefficient, and gas permeation. What has a rate can be illustrated preferably.
The polyester resin in the present invention includes a deposited film in which a metal oxide such as silicon, aluminum, chromium or magnesium, nitride, or the like is deposited on the surface thereof. Among these, the vapor deposition film which vapor-deposited metal oxide and its mixture on the surface can be used preferably, and the vapor deposition film which vapor-deposited silicon oxide, aluminum oxide, and magnesium oxide on the surface can be used preferably especially. Particularly preferable as such a deposited film is a film obtained by depositing silicon oxide on the surface of polyethylene terephthalate.

  It is not particularly limited as glass, silicate glass such as silicate glass, high silicate glass, alkali silicate glass, lead alkali glass, soda lime glass, potash lime glass, barium glass, alumina silicate glass, phosphate glass, no alkali Examples thereof include glass such as glass and tempered glass thereof. In terms of cost, soda lime glass is preferable, and tempered glass is preferable from the viewpoint of impact resistance. Also about these glass, what has Tg of the said range, Tm, a linear expansion coefficient, and gas permeability can be used preferably.

As specific examples of polyolefin, for example, polystyrene and ethylene-α-olefin resins having Tg, Tm, linear expansion coefficient and gas permeability in the above range can be preferably exemplified.
In addition, when using a polyolefin having a Young's modulus of less than 1 MPa as the buffer layer, the polyolefin is laminated so as to constitute a plurality of layers with a layer having a Young's modulus of 1 MPa or more. Among polyolefins, those having a Young's modulus of less than 1 MPa are not suitable as a buffer layer by themselves.

  The said buffer layer can be used individually by 1 type or in combination of 2 or more types. In addition, the buffer layer of the present invention may be in the form of a gel at the time of lamination, may be in the form of a film, or may be a solid different from that.

Moreover, it is preferable that the buffer layer is surface-treated in terms of enhancing the adhesiveness. Examples of the surface treatment method include corona treatment, plasma treatment, ozone treatment, UV irradiation, electron beam irradiation, and flame treatment.

The buffer layer included in the solar cell module of the present invention may exist as a single layer or a plurality of layers between the polycarbonate substrate and the sealing layer. When present as a single layer, the same type of material may be used, or a plurality of types of materials may be mixed to form a single layer.
When present as a plurality of layers, the types of materials constituting each layer may be the same or different.

The thickness of the buffer layer is preferably 10 μm or more, more preferably 20 μm or more, and particularly preferably 50 μm or more. On the other hand, the thickness of the buffer layer is preferably 200 μm or less, more preferably 150 μm or less, and particularly preferably 100 μm or less. When the thickness of the buffer layer is in the above range, the effect of the present invention can be better obtained. When the solar cell module of the present invention has a plurality of buffer layers, the thickness of at least one layer is preferably 10 μm or more, more preferably 20 μm or more, and particularly preferably 50 μm or more.
The ratio of the thickness of the buffer layer to the polycarbonate substrate is preferably 5 or more, more preferably 10 or more, and particularly preferably 20 or more when the buffer layer is 1. On the other hand, this ratio is preferably 60 or less, more preferably 40 or less, and particularly preferably 30 or less. By existing at such a ratio, the effect of the present invention can be obtained more remarkably.

<Power generation member>
The power generation member in the solar cell module of the present invention includes a power generation element that converts sunlight into electricity and a power generation element base material for suppressing a change in shape of the power generation element. In addition, a gas barrier layer, a wavelength conversion layer, and a UV absorption layer may be laminated as necessary.

<Power generation element>
The power generation element is an element that generates power based on sunlight incident from the weathering layer side. The power generating element is not particularly limited as long as it can convert light energy into electric energy and can extract the electric energy obtained by the conversion to the outside.

As a power generation element, a power generation layer (photoelectric conversion layer, light absorption layer) is sandwiched between a pair of electrodes, a stack of a power generation layer and another layer (buffer layer, etc.) is sandwiched between a pair of electrodes, and so on. A plurality of such things connected in series can be used.
Various layers can be adopted as the power generation layer, but a layer made of thin single crystal silicon, thin film polycrystalline silicon, amorphous silicon, microcrystalline silicon, spherical silicon, an inorganic semiconductor material, an organic dye material, or an organic semiconductor material It is preferable that By using these materials, a power generation efficiency is relatively high and a thin (light) power generation element can be realized. Furthermore, from the viewpoint of increasing efficiency, a HIT type or a tandem type in which these are laminated may be used.

  When the power generation layer is a thin-film polycrystalline silicon layer, the power generation element is a type of element that uses indirect optical transition. Therefore, when the power generation layer is a thin-film polycrystalline silicon layer, in order to increase light absorption, a sufficient light confinement structure, such as a power generation element substrate described later, or a surface with an uneven structure is provided. Is preferred.

  When the power generation layer is an amorphous silicon layer, a solar cell element 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. Moreover, since amorphous silicon is an amorphous material, it is resistant to deformation. Therefore, when the power generation layer is an amorphous silicon layer, a particularly lightweight solar cell module having a certain degree of resistance to deformation can be realized.

  When the power generation layer is an inorganic semiconductor material (compound semiconductor) layer, a power generation element 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-VI group 2 semiconductor system (chalcopyrite system) It is more preferable that the power generation layer be a Cu-III-VI group 2 semiconductor power generation layer using Cu as a group I element, particularly a CIS-based semiconductor [CuIn (Se1-ySy) 2; 0 ≦ y ≦ 1] layer, A CIGS-based semiconductor [Cu (In1-xGax) (Se1-ySy) 2; 0 <x <1, 0 ≦ y ≦ 1]] layer is preferable.

  Even if a dye-sensitized power generation layer composed of a titanium oxide layer and an electrolyte layer is employed as the power generation layer, a power generation element with high power generation efficiency can be realized, and an organic semiconductor layer (p-type semiconductor and n-type semiconductor) can be realized. A layer containing a semiconductor) can also 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. In addition, 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. .

  Further, n-type semiconductors that can constitute the organic semiconductor layer include fullerenes (C60, C70, C76); octaaporphyrins; perfluoro compounds of the above-mentioned p-type semiconductors; nafullerene tetracarboxylic acid anhydrides, naphthalene tetracarboxylics. 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) in which layers containing an n-type semiconductor (n layer) are stacked, a Schottky type, and a combination thereof.

Each electrode of the power generation element 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 thereof include a dispersed conductive composite material.

  The electrode material is preferably a material suitable for collecting holes or electrons. Examples of the electrode material suitable for collecting holes (that is, a material having a high work function) include gold and ITO. Examples of the electrode material suitable for collecting electrons (that is, a material having a low work function) include silver and aluminum.

Each electrode of the power generation element may be substantially the same size as the power generation layer or may be smaller than the power generation layer. However, if the electrode on the light receiving surface side (weatherproof layer side) of the power generation element is relatively large (the area is not sufficiently small compared to the power generation layer area), the electrode should be The electrode should be a transparent (translucent) electrode, particularly an electrode having a relatively high transmittance (for example, 50% or more) of light having a wavelength that can be efficiently converted into electric energy by the power generation layer. Examples of transparent electrode materials include oxides such as ITO and IZO (indium oxide-zinc oxide); metal thin films, and the like.

The thickness of each electrode of the power generation element and the thickness of the power generation layer can be determined based on the required output and the like.
Further, an auxiliary electrode may be provided so as to be in contact with the electrode. In particular, it is effective when using a slightly conductive electrode such as ITO. As the auxiliary electrode material, the same material as the above metal material can be used as long as the conductivity is good, but silver, aluminum, and copper are exemplified.

<Power generation element substrate>
The power generation element substrate is a member on which one of the power generation elements is formed. Therefore, the power generating element base material is desired to have a relatively high mechanical strength, excellent weather resistance, heat resistance, chemical resistance, and the like, and lightweight. It is also desirable that the power generating element substrate has a certain degree of resistance against deformation. 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 power generation element substrate.

  Examples of the metal foil that can be used as the power generation element substrate (or its constituent elements) 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, fluorine resin such as PVDF, PVF, silicone resin, cellulose, nitrile resin, phenol resin, polyurethane, ionomer, polybutadiene, polybutylene, polymethylpentene, polyvinyl alcohol, polyarylate, Examples thereof include films made of polyetheretherketone, polyetherketone, polyethersulfone and the like. The resin film used as the power generation element substrate may be a film in which glass fiber, organic fiber, carbon fiber, or the like is dispersed in the resin as described above.

  In addition, when the melting point of the resin film used as the power generation element base (or its constituent elements) is in the range of 85 to 350 ° C., the power generation element base does not deform and does not peel off from the power generation element. Therefore, it is preferable. Further, the melting point of the resin film used as the power generation element substrate (or its constituent elements) is more preferably 100 ° C. or higher, further preferably 120 ° C. or higher, and particularly preferably 150 ° C. or higher. Preferably, it 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.

<Weather-resistant layer>
The weather resistant 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. This weathering layer is preferably one that does not interfere with light absorption of the power generation element, that is, one that transmits light having a wavelength that can be efficiently converted into electric energy by the power generation layer. For example, the solar radiation transmittance is 80% or more. It is preferable that it is 85% or more.

Moreover, since a solar cell module is heated by sunlight, it is preferable that a weather resistant layer has heat resistance. Therefore, the constituent material of the weather resistant layer 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.

The material for the weathering layer can be selected in consideration of these characteristics. For example, polyethylene resin, polypropylene resin, cyclic polyolefin resin, AS (acrylonitrile-styrene) resin, ABS (acrylonitrile-butadiene-styrene) resin, polychlorinated Vinyl resins, fluorine resins, polyethylene resins such as polyethylene terephthalate, polyethylene naphthalate, phenol resins, polyacrylic resins, (hydrogenated) epoxy resins, polyamide resins such as various nylons, polyimide resins, polyamide-imide resins, polyurethane resins Cellulose-based resins, silicon-based resins, polycarbonate resins, and the like can be used as the constituent material of the weather resistant layer. Among these, from the viewpoint of weather resistance, it is preferable to use a fluorine-based resin such as ETFE (tetrafluoroethylene and ethylene copolymer).
The weather resistant layer may be composed of two or more materials. The weather resistant layer may be a single layer or a laminate composed of two or more layers. Furthermore, if necessary, the laminate surface may be subjected to a surface treatment such as corona treatment, plasma treatment, ozone treatment, UV irradiation, electron beam irradiation, or flame treatment.

  The thickness of the weathering layer is not particularly defined, but the mechanical strength tends to increase by increasing the thickness, and the flexibility tends to increase by decreasing the thickness. Therefore, the thickness of the weather resistant layer is usually 10 μm or more, preferably 15 μm or more, more preferably 20 μm or more, and usually 200 μm or less, preferably 180 μm or less, more preferably 150 μm or less. In short, as the weather resistant layer, various thickness layers made of materials having weather resistance, heat resistance and the like can be adopted.

<Sealing layer>
The solar cell module of the present invention has at least one sealing layer between the power generation member and the polycarbonate substrate. By providing the sealing layer, the power generating element described above can be sealed, and impact resistance and the like can be imparted to the solar cell module.
The material laminated as the sealing layer is a resin material having a relatively high solar transmittance, such as polyethylene, polypropylene, ethylene-vinyl acetate copolymer (EVA), ethylene-methyl acrylate copolymer, ethylene. -Use polyolefin resin such as ethyl acrylate copolymer, propylene-ethylene-α-olefin copolymer, butyral resin, styrene resin, epoxy resin, (meth) acrylic resin, urethane resin, silicone resin, synthetic rubber, etc. One or more mixtures or copolymers of these can be used.

  The thickness of the sealing layer is preferably 100 μm or more, more preferably 200 μm or more, and further preferably 300 μm or more. On the other hand, it is preferably 1000 μm, more preferably 800 μm or less, and even more preferably 500 μm or less. By setting the thickness of the sealing layer within the above range, moderate impact resistance can be obtained, and it is preferable from the viewpoint of cost and weight, and power generation characteristics can be sufficiently exhibited.

  In addition to being laminated between the power generation member and the buffer layer, the sealing layer is preferably laminated with the second sealing layer in contact with the light receiving surface side of the power generation member. By stacking in such a manner, it is possible to contribute to an improvement in impact resistance of the power generation element. In the solar cell module of this invention, the aspect by which a sealing layer is laminated | stacked so that the upper and lower sides of a power generation member may be pinched | interposed is preferable. By setting it as such an aspect, the favorable impact resistance of a power generating element can be provided. In such an embodiment, the second sealing layer laminated on the light receiving surface side is preferably laminated between the weather resistant layer and the power generation member from the viewpoint of ensuring weather resistance.

The ultraviolet absorber may be added to the sealing layer which the solar cell module of this invention has. Such ultraviolet absorbers can be used without particular limitation including those commercially available. Examples include benzophenone compounds, benzotriazole compounds, triazine compounds, and the like.
When an ultraviolet absorber is added to the sealing layer, the amount is preferably 0.01% by weight or more, more preferably 0.05% by weight or more based on the total amount of the sealing layer. On the other hand, the content is preferably 1% by weight or less, more preferably 0.8% by weight or less, and particularly preferably 0.6% by weight or less. This is because if it is less than 0.01% by weight, it is difficult to exhibit the ultraviolet absorption effect, and if it exceeds 1% by weight, it causes bleeding out.

<Adhesive layer>
In the solar cell module of the present invention, a polycarbonate substrate is used, but it is preferable to have an adhesive layer between the polycarbonate substrate and the buffer layer. By having the adhesive layer, an effect of absorbing strain that cannot be absorbed by the buffer layer alone can be obtained.

The adhesive layer in the present invention may be a single layer or a plurality of layers, and may contain a plurality of resins.
The resin contained in the adhesive layer is not particularly limited, for example, preferably includes at least a resin having an adhesive function with a polycarbonate substrate, and the resin having an adhesive function with a polycarbonate substrate includes a vinyl acetate resin, Examples thereof include urethane resin, epoxy resin, acrylic resin, methacrylic resin, olefin resin, vinyl acetate resin, chloroprene rubber, and nitrile rubber. Among these, it is preferable to include vinyl acetate resin, urethane resin, acrylic resin, methacrylic resin, and olefin resin from the viewpoint of adhesiveness and heat durability.
Further, these resins are preferably copolymers from the viewpoints of adhesion at different interfaces and thermal durability.
A copolymer is also preferred because it allows adjustment of compatibility between a plurality of resins, adhesion between the upper and lower layers of the adhesive layer, and the like. Examples of such a copolymer include ethylene-vinyl acetate copolymer (EVA), ethylene-methyl acrylate copolymer, and ethylene-ethyl acrylate copolymer.

The thickness of the adhesive layer is usually 10 μm or more, preferably 50 μm or more.
It is more preferably 0 μm or more, and further preferably 300 μm or more. The upper limit is usually 1000 μm or less, preferably 800 μm, and 500 μm.
Or less, more preferably 400 μm or less. When the film thickness is in the above range, problems due to the difference in linear expansion between the polycarbonate substrate and the adhesive layer are unlikely to occur. Moreover, when applying an adhesive layer to a polycarbonate base material, it can be set as favorable smoothness, and an adhesive fall does not arise.

  In the solar cell module of the present invention, when the adhesive layer is laminated between the buffer layer and the polycarbonate substrate, ETFE, PEN, and PET are used as the buffer layer material, and EVA and urethane are used as the adhesive layer material. It is preferable to use a base resin or an olefin resin from the viewpoint of strain absorption and module appearance.

<Method for manufacturing solar cell module>
The solar cell module of the present invention is laminated in the order of a weathering layer, a power generation member (power generation element, power generation element base material), a sealing layer, a buffer layer and a polycarbonate base material, preferably also between the weathering layer and the power generation member. It has a sealing layer and has an adhesive layer between the buffer layer and the polycarbonate substrate. A method of laminating each layer can be a commonly used method, but it is preferable to laminate each constituent layer by thermal lamination (vacuum lamination) from the viewpoint of productivity and long-term durability.

  Moreover, as a procedure for integrating the solar cell modules, a method of laminating a weather resistant layer, a power generation member (power generation element, power generation element base material), a sealing layer, a buffer layer, and a polycarbonate base material in this order and heat laminating can be given. It is done. Further, any of the layers may be subjected to surface treatment such as corona treatment, plasma treatment, ozone treatment, UV irradiation, electron beam irradiation, or flame treatment.

The heat laminating conditions are not particularly limited, and heat laminating is possible under normal conditions.
The thermal lamination 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 is also improved, it is preferable.
The vacuum time is usually 1 minute or longer, preferably 2 minutes or longer, more preferably 3 minutes or longer. On the other hand, the upper limit is usually 8 minutes or less, preferably 6 minutes or less, more preferably 5 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 generation of bubbles due to heat lamination conditions can be suppressed in each layer in the module.

The pressurizing condition of the thermal laminate is usually a pressure of 50 kPa or more, preferably 70 kPa or more, more preferably 90 kPa or more. On the other hand, the upper limit value is preferably 101 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 holding time of the pressure 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 30 minutes or less, preferably 20 minutes or less, more preferably 15 minutes or less. By setting the holding time, sufficient adhesive strength can be obtained.

The temperature condition of the thermal laminate is usually 120 ° C. or higher, preferably 130 ° 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.
The temperature holding time is usually 5 minutes or longer, preferably 12 minutes or longer, more preferably 15 minutes or longer. On the other hand, the upper limit is 30 minutes or less, preferably 20 minutes or less. By setting it as the said holding time, since crosslinking of a sealing layer is performed moderately and durability performance can improve and it can have moderate softness | flexibility, it is preferable.

  The solar cell module of the present invention includes a solar cell for building materials, a solar cell for automobiles, a solar cell for interiors, a solar cell for railways, a solar cell for ships, a solar cell for airplanes, a solar cell for spacecraft, a solar cell for home appliances, a mobile phone. It can be suitably used for a solar cell for telephones, a solar cell for toys and the like. Preferably, it is a solar cell for building materials.

The solar cell module of this invention is demonstrated with reference to drawings.
FIG. 1 is a schematic view according to one embodiment of the solar cell module of the present invention. In the solar cell module, an adhesive layer 7, a buffer layer 6, a sealing layer 5, a power generation member 4, a sealing layer 3 and a weathering layer 2 are laminated on a polycarbonate substrate 8 in this order. Thus, by providing the adhesive layer 7 between the polycarbonate base material 8 and the sealing layer 5, the strain of the polycarbonate base material caused by the heat shrinkage during the production of the solar cell module is absorbed and generated by this layer. By letting gas escape to the outside, it is possible to prevent bubbles from accumulating inside the solar cell module.

Hereinafter, the solar cell module of the present invention will be described in more detail using examples,
Needless to say, the present invention is not limited to the embodiments.

<Example 1>
(Production of solar cell module for evaluation)
50 μm thick ethylene-tetrafluoroethylene copolymer (hereinafter referred to as ETFE) film (50HK-DCS manufactured by Asahi Glass Co., Ltd.), 300 μm thick ethylene-vinyl acetate copolymer (hereinafter referred to as EVA) film (FIRST manufactured by FIRST), power generation member (polyethylene naphthalate (hereinafter referred to as PEN) film, an amorphous silicon-based power generation layer laminated), the same EVA film, and the same ETFE film (Tg = 100 ° C., Tm = 2
60 ° C., linear expansion coefficient (MD): 59 ppm / K, Young's modulus: 800 MPa, water vapor transmission rate: 12 g / m ² / day), the same EVA film as an adhesive layer, and a polycarbonate substrate with a thickness of 2 mm (manufactured by Mitsubishi Plastics) In this order, using a vacuum laminator manufactured by NPC, heat laminate at 135 ° C. (vacuum degree 80 Pa, vacuum time 5 minutes, pressurization time 5 minutes, holding 20 minutes) to obtain a solar cell module for appearance evaluation. Produced.
(Appearance evaluation)
No bubbles or peeling occurred between the buffer layer / polycarbonate substrate.

<Example 2>
(Production of solar cell module for evaluation)
ETFE film with a thickness of 50 μm (50HK-DCS manufactured by Asahi Glass Co., Ltd.), EVA film with a thickness of 300 μm (F806 manufactured by FIRST), power generation member (amorphous silicon-based power generation layer is laminated on the PEN film), the same EVA film, An upper module was manufactured by stacking the ETFE films in this order and using a vacuum laminator manufactured by NPC, and heat laminating at 135 ° C. (vacuum degree 80 Pa, vacuum time 5 minutes, pressurization time 5 minutes, holding 20 minutes). Furthermore, the upper module, the same EVA film, and a polycarbonate substrate with a thickness of 2 mm (Mitsubishi Resin, dried in an oven under a nitrogen flow heated to 135 ° C. for 30 minutes) are stacked, and a vacuum laminator manufactured by NPC is used. And solar lamination at 135 ° C. (vacuum degree 80 Pa, vacuum time 5 minutes, pressurization time 5 minutes, holding 20 minutes).
(Appearance evaluation)
No bubbles or peeling occurred between the buffer layer / polycarbonate substrate.

<Example 3>
(Production of solar cell module for evaluation)
ETFE film of 50 μm thickness (50HK-DCS manufactured by Asahi Glass Co., Ltd.), EVA film of 300 μm thickness (F806 manufactured by FIRST), power generation member (stacked amorphous silicon-based power generation layer on PEN film), EVA film, buffer P layer with a thickness of 38μm
ET film (Mitsubishi Resin T100E38: Tg = 76 ° C., Tm = 255 ° C., linear expansion coefficient (MD): 60 ppm / K, Young's modulus 500 MPa, water vapor transmission rate: 21 g / m ² / day), EVA film, thickness 2mm thick polycarbonate base material (Mitsubishi Resin Co., Ltd.), laminated using NPC vacuum laminator and heat laminated at 150 ° C (vacuum degree 80Pa, vacuum time 5 minutes, pressurization time 5 minutes, holding 5 minutes ) To produce a solar cell module for appearance evaluation. (Appearance evaluation)
No bubbles or peeling occurred between the buffer layer / polycarbonate substrate.

<Example 4>
(Production of solar cell module for evaluation)
ETFE film of 50 μm thickness (50HK-DCS manufactured by Asahi Glass Co., Ltd.), EVA film of 300 μm thickness (F806 manufactured by FIRST), power generation element (amorphous silicon-based power generation layer is laminated on PEN film), EVA film, buffer As the layer, ETFE film, 60 μm thick silica-deposited PET film (Mitsubishi Resin Tech Barrier VDC3: Tg)
= 76 ° C., Tm = 255 ° C., linear expansion coefficient: 60 ppm / K, Young's modulus 500 MPa, water vapor transmission rate: 1 × 10 ⁻³ g / m ² / day), EVA film, polycarbonate substrate (thickness 2 mm) (Mitsubishi Resin) in this order, using a vacuum laminator manufactured by NPC, and heat laminated at 150 ° C (vacuum degree 80 Pa, vacuum time 5 minutes, pressurization time 5 minutes, holding 5 minutes) A battery module was produced.
(Appearance evaluation)
No bubbles or peeling occurred between the buffer layer / polycarbonate substrate.

<Example 5>
(Production of solar cell module for evaluation)
ETFE film of 50 μm thickness (50HK-DCS manufactured by Asahi Glass Co., Ltd.), EVA film of 300 μm thickness (F806 manufactured by FIRST), power generation element (amorphous silicon-based power generation layer is laminated on PEN film), EVA film, buffer The same ETFE film, 500 μm thick alkali glass substrate (Tg = 550 ° C., Tm = 1400 ° C., linear expansion coefficient: 3.7 ppm / K, Young's modulus 2000 MPa, water vapor transmission rate: 1 × 10 ⁻⁸ g / m ² /
day), the same EVA film, and a 2 mm-thick polycarbonate substrate (Mitsubishi Resin Co., Ltd.) in this order, and using a NPC vacuum laminator, heat laminate at 150 ° C. (vacuum degree 80 Pa, vacuum time 5 minutes, heat treatment) The solar cell module for appearance evaluation was manufactured by pressing for 5 minutes and holding for 5 minutes.
(Appearance evaluation)
No bubbles or peeling occurred between the buffer layer / polycarbonate substrate.

<Comparative Example 1>
(Production of solar cell module for evaluation)
A 50 μm thick ETFE film (Asahi Glass Co., Ltd. 50HK-DCS), a 300 μm thick EVA film (FIRST F806), a power generating element, the same EVA film, and a 2 mm thick polycarbonate substrate (Mitsubishi Resin) are stacked. In addition, using a vacuum laminator manufactured by NPC, thermal lamination was performed at 135 ° C. (vacuum degree: 80 Pa, vacuum time: 5 minutes, pressurization time: 5 minutes, retention: 20 minutes) to produce a solar cell module for appearance evaluation.
(Appearance evaluation)
Generation of bubbles was confirmed between the buffer layer / polycarbonate substrate.

<Comparative example 2>
(Production of solar cell module for evaluation)
ETFE film with a thickness of 50 μm (50HK-DCS manufactured by Asahi Glass Co., Ltd.), EVA film with a thickness of 300 μm (F806 made by FIRST), power generation element, EVA film with a thickness of 300 μm (F806 made by FIRST), polyolefin with a thickness of 450 μm Film (Tg = −50 ° C., Tm = 85 ° C., linear expansion coefficient 120 ppm, Young's modulus 0.4 MPa, water vapor transmission rate: 18 / m ² / day), the same EVA film, 2 mm thick polycarbonate substrate (
A solar cell module for external appearance evaluation by superimposing (Mitsubishi Resin Co., Ltd.) and heat laminating at 135 ° C using a vacuum laminator manufactured by NPC (vacuum degree 80 Pa, vacuum time 5 minutes, pressurization time 5 minutes, holding 20 minutes) Was made.
(Appearance evaluation)
Generation of bubbles was confirmed between the buffer layer / polycarbonate substrate.

1 Sunlight 2 Weatherproof layer 3 Sealing layer (second one)
4 Power generation members (power generation elements and power generation element base materials)
5 Sealing layer 6 Buffer layer 7 Adhesive layer 8 Polycarbonate substrate

Claims (6)

  A solar cell module in which a weathering layer, a power generation member, a sealing layer, and a polycarbonate base material are laminated in this order, having a buffer layer between the sealing layer and the polycarbonate base material, The solar cell module, wherein the buffer layer includes a layer having a Young's modulus of 1 MPa or more. The solar cell module according to claim 1, wherein the buffer layer includes a layer having the following physical properties (1) and (2).
(1) Tg: 0 to 200 ° C
(2) Young's modulus: 300 to 3000 MPa   The solar cell module according to claim 1, wherein the buffer layer includes a layer having a Tm of 100 ° C. or more.   The said buffer layer consists of 1 or more materials selected from the group which consists of a fluororesin, polyester, glass, and polyolefin, The solar cell module as described in any one of Claims 1-3 characterized by the above-mentioned.   The solar cell module according to claim 1, further comprising an adhesive layer between the buffer layer and the polycarbonate substrate.   The solar cell module according to claim 5, wherein the adhesive layer is made of one or more materials selected from the group consisting of an ethylene-vinyl acetate copolymer, a urethane resin, and an acrylic resin.

Images