JP2015082611A - Snow-melting sheet with integrated solar cell and method for installing snow-melting sheet with integrated solar cell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a snow-melting sheet with an integrated solar cell, which can be installed easily, and a replacement work of which can be also performed easily.SOLUTION: A snow-melting sheet 10a with an integrated solar cell is a solar cell having flexibility and includes a solar cell element 2a comprising amorphous silicon and a heating element 3a comprising conductive fibers which are laminated between a front surface protective layer 1a and a rear surface protective layer 5a, while being embedded in a sealing material layer 4a formed of EVA. That is, the snow-melting sheet 10a with an integrated solar cell includes the front surface protective layer 1a, the solar cell element 2a and the heating element 3a, in the order, and has a structure where the solar cell element 2a and the heating element 3a are sealed with the sealing material layer 4a.

Description

  The present invention relates to a snow melting sheet, and more particularly, to a solar cell integrated snow melting sheet preferably used in a snowfall area.

As a snowmelt roofing material, a structure in which a planar (sheet-like) heating heater is arranged together with a solar cell is known (see Patent Documents 1 to 3).
In these structures, snow accumulated on the solar cell is melted by a heater, and the solar cell is integrated with the roofing material.

JP-A-11-131709 JP 2000-27378 A JP 2006-144469 A

Since all of the above proposals for snow melting roof materials are ones in which solar cells and roof materials are integrated, it is necessary to replace the entire roof when installing it on an existing roof. I had to be a big deal. Moreover, when it became necessary to replace | exchange a solar cell, it was necessary to replace | exchange the whole roof similarly.
An object of the present invention is to provide a solar cell-integrated snow melting sheet that can be easily installed and can be easily replaced.

The present inventors have studied to solve the above problems. Then, the present inventors completed the present invention by conceiving a solar cell integrated snow melting sheet having a simple structure that can be installed on a roof.
The first embodiment of the present invention is:
It is a solar cell integrated snow melting sheet having a surface protective layer, a solar cell element, and a heating element in this order and having flexibility.

Moreover, it is a preferable aspect that the solar cell element and the heating element have a structure sealed with a sealing material, and a surface protective layer is provided on the surface of the structure on the solar cell element side.
Moreover, it is preferable to have an insulating layer between the said solar cell element and the said heat generating body, and it is a preferable aspect that the said solar cell element is sealed with the sealing material.
Moreover, it is a preferable aspect that the said solar cell element is a thin film type solar cell element.
Moreover, it is preferable that the said heat generating body is a planar heat generating body, and is comprised from the electroconductive fiber.
Moreover, it is preferable to further have a back surface protective layer.
Moreover, it is preferable that the member which comprises the layer of a solar cell integrated snow-melting sheet | seat other than the said solar cell element and a heat generating body consists of resin materials, and it can wind in roll shape.

In addition, by using the roll-shaped solar cell integrated snow melting sheet, which is a preferred aspect of the first embodiment, installation on the roof becomes extremely easy. The second embodiment of the present invention is:
A method for installing a solar cell-integrated snow-melting sheet comprising the step of spreading the solar cell-integrated snow-melting sheet having the above-described roll shape at an installation site.

  According to the present invention, it is possible to provide a solar cell-integrated snow melting sheet that can be easily installed and can be easily replaced. Conventionally, a stand is used for installing a solar cell on a roof, but according to the present invention, there is no need for it. Conventionally, when installing a solar cell integrated roof material, it was necessary to replace the existing roof. According to the present invention, the solar cell integrated snow melting sheet can be installed without replacing the existing roof. .

It is a schematic diagram which shows an example of the specific embodiment of the solar cell integrated snow melting sheet | seat of this invention. It is a schematic diagram which shows an example of the specific embodiment of the solar cell integrated snow melting sheet | seat of this invention. It is a schematic diagram which shows an example of the specific embodiment of the solar cell integrated snow melting sheet | seat of this invention.

Hereinafter, the present invention will be described in detail while showing specific embodiments, but it is needless to say that the present invention is not limited to the illustrated specific embodiments.
The solar cell integrated snow melting sheet according to an embodiment of the present invention has a structure having a surface protective layer, a solar cell element, and a heating element in this order. Hereafter, each structure is demonstrated in order.

<1. Surface protective layer>
The solar cell integrated snow melting sheet according to this embodiment includes a surface protective layer. Since the solar cell-integrated snow-melting sheet is installed on the roof and exposed to rain and wind, the surface protective layer preferably has impact resistance and weather resistance.
From the viewpoint of supplying a large amount of sunlight to the solar cell, the surface protective layer has a total light transmittance of 80% or more, preferably 90% or more. The upper limit is not particularly limited, but is usually 99% or less. The measuring method of a total light transmittance is based on JISK7361-1, for example.

Specific materials for the surface protective layer include polycarbonate (PC), polymethyl methacrylate (PMMA), cyclic polyolefin, polystyrene, polyethylene terephthalate (PET), polyethylene naphthalate (PEN), ethylene-tetrafluoroethylene copolymer ( ETFE), polytetrafluoroethylene (PTFE), polypropylene (PP), polyethylene (PE) and the like.
Preferable examples include fluorine resins such as ethylene-tetrafluoroethylene copolymer (ETFE) and polytetrafluoroethylene (PTFE), polycarbonate (PC), and polymethyl methacrylate (PMMA).

  The thickness of the surface protective layer is usually 0.02 mm or more. The thickness is preferably 0.03 mm or more or more than 0.03 mm, more preferably 0.05 mm or more. On the other hand, the upper limit is not particularly limited, but is preferably 5 mm or less, more preferably 3 mm or less, and still more preferably 2 mm or less. By setting it as the above range, both impact resistance and flexibility can be achieved.

<2. Solar cell element>
The solar cell element 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 this embodiment, one unit of the power generation element is referred to as a unit solar cell.
The power generation element is an element that generates power based on sunlight incident from the surface protection 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. The thing which connected several things in series can be used. Various layers can be used 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. Further, from the viewpoint of increasing efficiency, a HIT type or a tandem type in which these are laminated may be used. In addition, since the solar cell integrated snow melting sheet in this embodiment has flexibility, the solar cell element also has flexibility. Therefore, the thin film solar cell element is preferable. The thin film solar cell element has a thickness of usually 1 μm or more, preferably 10 μm or more, more preferably 25 μm or more. Moreover, it is 800 micrometers or less normally, Preferably it is 500 micrometers or less, More preferably, it is 300 micrometers or less.

  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 that has a large optical absorption coefficient in the visible range 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 to set it as a power generation layer, and a Cu-III-VI group 2 semiconductor power generation layer using Cu as a group I element, particularly a CIS-based semiconductor [CuIn (Se _1-y S _y ) 2; 0 ≦ y ≦ 1 ] layer and a CIGS semiconductor _{[Cu (in 1-x Ga x} ) (Se 1-y S y) 2; 0 < be kept as x <1,0 ≦ y ≦ 1]] layer, preferred.

  Even when a dye-sensitized power generation layer including 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. An organic semiconductor layer (a layer including a p-type semiconductor and an n-type semiconductor) can also be employed.

  Specific examples of the structure of the organic semiconductor layer include 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, a layer containing a p-type semiconductor (p layer), and n, respectively. A layered type (hetero pn junction type), a PIN type, a Schottky type, and a combination thereof in which layers (n layers) including a type semiconductor are stacked can be given. Among these, a bulk heterojunction type is preferable.

A p-type semiconductor compound is a material that operates as a p-type semiconductor whose film can transport holes, but a π-conjugated polymer material or a π-conjugated low-molecular organic compound is preferably used. A mixture of these compounds may also be used. The conjugated polymer material is obtained by polymerizing a single or a plurality of π-conjugated monomers. Examples of the monomer include thiophene, fluorene, carbazole, diphenylthiophene, dithienothiophene, dithienosilole, dithieno which may have a substituent. Examples include cyclohexane, benzothiadiazole, thienothiophene, imidothiophene, benzodithiophene, and the like, and the molecular weight is 10,000 or more. These monomers may be directly bonded or may be bonded via CH═CH, C≡C, N, or O. Low molecular organic semiconductor materials include condensed aromatic hydrocarbons such as pentacene and naphthacene, oligothiophenes having four or more thiophene rings, porphyrin compounds, tetrabenzoporphyrin compounds and their metal complexes, phthalocyanine compounds and their metal complexes, etc. .

The n-type semiconductor compound is not particularly limited, and examples thereof include fullerene compounds and derivatives thereof, and condensed ring tetracarboxylic acid diimides. Examples of fullerenes include C60 or C70, and those obtained by adding a substituent to two carbons of the fullerene, those having a substituent added to four carbons, and further adding a substituent to six carbons. Things. In order for the fullerene compound to be applicable to a coating method, the fullerene compound is preferably highly soluble in some solvent and can be applied as a solution.
When an organic semiconductor layer is used for the power generation layer, it is preferable to stack a hole extraction layer and / or an electron extraction layer.

  The material of the hole extraction layer is a conductive polymer in which polythiophene, polypyrrole, or polyaniline is doped with sulfonic acid and / or halogen, or a metal oxide having a large work function such as molybdenum oxide or nickel oxide. Used.

  Although the material of an electron extraction layer is not specifically limited, Specifically, an inorganic compound or an organic compound is mentioned. Examples of the inorganic compound include alkali metal salts such as LiF, and n-type oxide semiconductors such as titanium oxide (TiOx) and zinc oxide (ZnO). Examples of the organic compound include phenanthrene derivatives such as bathocuproine (BCP) and bathophenanthrene (Bphen), and phosphine compounds having a P═O or P═S structure. Among them, an aromatic hydrocarbon group or an aromatic group is included in the phosphorus atom. A heterocyclic group phosphine compound is preferred.

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, A material containing a dopant such as a Lewis acid such as FeCl ₃ , a halogen atom such as iodine, or a metal atom such as sodium or potassium; conductive particles such as metal particles, carbon black, fullerene, or carbon nanotubes, and a matrix such as a polymer binder And conductive composite materials dispersed in the 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, when 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.

  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.

<3. Heating element>
The solar cell integrated snow melting sheet according to this embodiment has a heating element. Because the heating element generates heat, it can snow on the solar cell-integrated snow-melting sheet and melt the snow that has accumulated, so it is possible to secure the daylighting necessary for power generation even when installed in snowy areas. it can.
The material and thickness of the heating element are not limited as long as the solar cell-integrated snow melting sheet has flexibility. As the heating element, a sheet heating element in which conductive wires such as nichrome wire and carbon are embedded in the film, a sheet heating element in which a warm fluid channel such as warm water is provided in the film, and a conductive filler in the film. Sheet heating element dispersed in, sheet heating element coated with metal or carbon black, carbon nanotube or conductive fiber containing these, sheet heating element coated with conductive paint on film, etc. can give. The planar heating element referred to in the present invention includes those capable of forming a sheet including a heating element, and even a heating wire such as a nichrome wire is embedded in a resin or the like to form a sheet. Included in the planar heating element in the present invention.
Among these, it is preferable to use a planar heating element composed of conductive fibers coated with carbon black or carbon nanotubes because the heating element portion can be manufactured thinly. The material of the conductive fiber is not particularly limited, and examples thereof include polyester, nylon, polyvinyl alcohol, and glass.

The resin material that can be used for the heating element is not particularly limited, but examples thereof include silicone, silicone rubber, polycarbonate, epoxy, polyester, nylon, vinyl chloride, polyvinyl alcohol, acrylic, polyimide, and fluorine resin. A resin that does not change its structure due to heat generation is preferred.
If the heating element can be provided with the functions of the back surface protection layer (weather resistance, impact resistance, etc.) by using silicone rubber, vinyl chloride, etc. as the resin material of the heating element, install the back surface protection layer. It may be omitted.
The thickness of the heating element is not particularly limited, but in the case of a planar heating element, it is preferably 10 μm or more, more preferably 50 μm or more from the viewpoint of having good flexibility. On the other hand, 5 mm or less is more preferable, and 2 mm or less is more preferable.

<4. Other layers>
In this embodiment, in addition to the above, other layers can be provided as long as the effects of the present invention are not impaired. Examples of the other layers include a back surface protective layer, a surface protective sheet, a sealing material layer, an insulating layer, an adhesive layer, and a reinforcing layer.

<4-1. Back surface protective layer>
The solar cell integrated snow melting sheet according to this embodiment may have a back surface protective layer. The back surface protective layer is a layer having a weather resistance and impact resistance function. As described above, when the heating element has a function that the back surface protective layer should have, such as weather resistance and impact resistance, the back surface protective layer is not essential.
Since the solar cell integrated snow melting sheet according to this embodiment has flexibility, the back surface protective layer is preferably a resin sheet.
Resin sheets include ethylene-tetrafluoroethylene copolymer (ETFE), perfluoroalkoxy fluororesin (PFA), tetrafluoroethylene / hexafluoropropylene copolymer (FEP), polychlorotrifluoroethylene (PCTFE). , Polycarbonate (PC), polyimide (PI), polystyrene (PS), polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyamide (PA), polymethyl methacrylate (PMMA) Polyolefin elastomers, polyester elastomers, etc. are preferable as polyvinyl chloride resin (PVC) and thermoplastic elastomer (TPO), and ETFE, PC, PVC, TPO are particularly preferred because of their good mechanical properties and light resistance. PMMA is desirable.

The thickness of the back surface protective layer is usually 0.01 mm or more, preferably 0.05 mm or more, and usually 5 mm or less, preferably 3 mm or less, from the viewpoint of imparting lightness and flexibility.
In addition, since the solar cell integrated snow melting sheet | seat of this embodiment has a heat generating body, it can also give heat insulation to a back surface protective layer. From such a viewpoint, a foamable resin layer such as urethane foam may be used as the back surface protective layer.
The back surface protective layer may be a laminate in order to impart the required performance.

<4-2. Surface protection sheet>
In this embodiment, a surface protective sheet may be further provided on the outer side (sunlight side) of the surface protective layer. It is preferable to provide the surface protective sheet because the surface protective layer is prevented from being damaged or deteriorated and the total light transmittance is maintained. The material constituting the surface protection sheet is preferably a weather-resistant film,
Conventionally used known materials can be used.

Examples of the resin used as the material for the weather resistant film include ethylene-tetrafluoroethylene copolymer (ETFE), silicone, polyethylene terephthalate, and polyamide. Among these, ethylene-tetrafluoroethylene copolymer (ETFE) is preferable.
The thickness of the surface protective sheet is not particularly limited, but is usually 10 μm or more, preferably 20 μm or more, and is usually 200 μm or less, preferably 150 μm or less.

<4-3. Sealing material layer>
In this embodiment, usually, at least one sealing material layer is provided between the solar cell element and the above-described surface protective layer and / or heating element. By providing such a sealing material layer, the solar cell element can be sealed, and impact resistance and the like can be imparted to the solar cell integrated snow melting sheet.
The sealing material layer is preferably stacked so as to sandwich the upper and lower sides of the solar cell element. By sealing the solar cell element, the durability of the solar cell integrated snow melting sheet of the present invention can be improved.

  The material laminated as the sealing material layer is a resin material having a relatively high solar transmittance, such as polyethylene, polypropylene, ethylene-vinyl acetate copolymer (EVA), ethylene-methyl acrylate copolymer, Uses polyolefin resin such as ethylene-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. Of these, EVA is preferable.

  The thickness of the sealing material 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 600 μm or less. By setting the thickness of the sealing material layer within the above range, moderate impact resistance can be obtained, which is preferable from the viewpoint of cost and weight, and power generation characteristics can be sufficiently exhibited.

It is preferable that the sealing material layer which concerns on this embodiment contains a silane coupling agent. By including the silane coupling agent, the adhesion between the sealing material layer and the layer in contact with the sealing material layer is improved. Preferred examples of the silane coupling agent include those having an alkyl group as a functional group, and specific examples include an epoxy group, a methacryl group, and a vinyl group. The weight ratio of the sealing material to the silane coupling agent is preferably 0.1 parts by weight or more and 2.0 parts by weight or less, and 0.3 parts by weight or more and 1.0 parts by weight with respect to 100 parts by weight of the sealing material. The amount is more preferably 0.5 parts by weight or less, and particularly preferably 0.5 parts by weight or more and 0.7 parts by weight or less. By setting it as such a range, adhesiveness can be made suitable. The phrase “containing a silane coupling agent” as used herein means adding or mixing the silane coupling agent to the encapsulant, and the silane coupling agent is added to or mixed with the encapsulant in advance before lamination. Alternatively, it may be added to or mixed with the sealing material during lamination.
Since the material used for the sealing material layer usually has adhesiveness, it can also be provided as an adhesive layer between the heating element and the solar cell element or between the surface protective sheet and the surface protective layer. When the adhesive layer is used, the thickness is preferably 3 μm or more and 500 μm or less.

<4-4. Insulating layer>
In this embodiment, an insulating layer may be further provided as necessary. The material used for the insulating layer is not particularly limited as long as it is a material that is difficult to conduct electricity. By providing such an insulating layer, it is possible to prevent electricity generated in the solar cell element from coming out of the outside of the collector line, so that the power generation efficiency of the solar cell is improved.
As a material for the insulating layer, for example, a fluorine resin such as ETFE (tetrafluoroethylene and ethylene copolymer), polyethylene terephthalate (PET), polyethylene naphthalate (PEN), or the like can be used.
In addition, although the arrangement position of an insulating layer is not specifically limited, It is preferable to arrange | position between a solar cell element and a heat generating body.

  Although the thickness of an insulating layer is not specifically limited, Usually, it is 0.01 mm or more, Preferably it is 0.02 mm or more, More preferably, it is 0.05 mm or more. On the other hand, the upper limit is usually 1.0 mm or less, preferably 0.5 mm or less, and more preferably 0.2 mm or less. If it is too thin, the insulation properties will be reduced, and if it is too thick, the flexibility of the solar cell integrated snow melting sheet will be lost.

<4-5. Reinforcing layer>
The reinforcing layer is a layer disposed between the surface protective layer and the solar cell element or between the solar cell element and the heating element photoelectric conversion layer, and has a function of protecting the solar cell element from physical impact from the outside, It is a layer having a function of preventing damage to the solar cell element due to heat shrinkage stress from the front and back surface protective layers and the sealing layer generated when the temperature is lowered.
The number of reinforcing layers is not particularly limited, but is usually 1 to 2 layers.

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.
The linear expansion coefficient of the reinforcing layer is preferably small from the viewpoint of suppressing thermal deformation. However, a large negative value is not preferable because thermal distortion inside the solar cell increases. Specifically, −10 to 40 ppm / K is preferable, 0 to 30 ppm / K is more preferable, and 5 to 20 ppm is still more preferable.
The thickness of the reinforcing layer is not particularly limited, but is usually 10 μm or more, preferably 25 μm or more, and more preferably 50 μm or more. On the other hand, the upper limit is usually 1000 μm or less, preferably 500 μm or less.

<5. Manufacturing method of solar cell integrated snow melting sheet>
Although the manufacturing method of the solar cell which concerns on this embodiment can use a well-known method, for example, the multilayer sheet containing a surface protective layer, a sealing material layer, a solar cell element, a sealing material layer, a heat generating body, a back substrate, etc. It can be obtained by placing in a vacuum lamination device, heating after vacuuming, and cooling after a certain time.

The said hot press conditions are not specifically limited, It can implement on the conditions performed normally.
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 of a solar cell 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 after hot pressing is improved and the generation of bubbles in each layer of the solar cell can be suppressed.

The press condition of the hot press 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 the pressurizing condition within the above range, it is preferable from the viewpoint of durability because it is possible to obtain appropriate adhesiveness without damaging the solar cell.

  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 it as the said holding time, the function which protects the electric power generating element of a sealing material layer can fully be exhibited, and sufficient adhesive strength can be obtained.

  The temperature condition of the hot press is usually 120 ° C. or higher, preferably 130 ° C. or higher, more preferably 140 ° 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 10 minutes or more normally, Preferably it is 12 minutes or more, More preferably, it is 15 minutes or more. On the other hand, the upper limit is 60 minutes or less, preferably 45 minutes or less, more preferably 30 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.

Moreover, the method for producing a solar cell integrated snow melting sheet according to the present embodiment includes, for example, arranging a multilayer sheet including a surface protective layer, a sealing material layer, a solar cell element, and a sealing material layer in a vacuum lamination device, After making a vacuum and then heating and cooling after a certain period of time to make an integrated laminate, the heating element and the back surface protective layer can be attached to the laminate with the multilayer sheet integrated with an adhesive. can get. Furthermore, for example, a surface protection layer, a sealing material layer, a solar cell element, a multilayer sheet including a sealing material layer, and a multilayer sheet including a heating element and a back surface protection layer are separately placed in a vacuum lamination apparatus, and evacuated. Then, after making a laminated body by heating and cooling after a lapse of a certain time, a laminated body in which the multilayer sheet including such solar cell elements is integrated with the multilayer sheet including a heating element. It can also be obtained by attaching the body with an adhesive.
When an adhesive is used to manufacture a solar cell integrated snow melting sheet, a cyanoacrylate adhesive, an acrylic adhesive, an acrylic adhesive, a polyolefin adhesive, a polyvinyl butyral adhesive, an ethylene-vinyl acetate copolymer ( EVA) -based adhesives, vinyl chloride-based adhesives, chloroprene rubber-based adhesives, silicone-based adhesives, polyamide-based adhesives, and the like can be used.

<6. Solar cell integrated snow melting sheet>
The solar cell integrated snow melting sheet according to the present embodiment has flexibility. Specifically, even if the solar cell integrated snow melting sheet is bent or bent, the solar cell element and the power generation element are not damaged. As a preferable flexibility, the curvature radius of the sheet is 300 mm or less, more preferably, the curvature radius is 200 mm or less, and still more preferably, the curvature radius is 150 mm or less. By setting it as the said range, it can convey in the state wound by roll shape, and can be installed more efficiently.

The thickness of the solar cell integrated snow melting sheet is not particularly limited, but should not be too thick from the viewpoint of flexibility. The preferred thickness is 10 mm or less, more preferably 7 mm or less, and still more preferably 4 mm or less. If it is too thick, it becomes difficult to bend and deflect, and the flexibility is hindered.
In order to have flexibility, it is necessary that each of the constituent layers is made of a material that can be bent and deflected. Therefore, it is preferable that all members constituting the layers other than the solar cell element and the heating element are made of a resin material.
Furthermore, it is important from the viewpoint of the snow melting function that the material exposed on the front surface, back surface, end portion and the like of the solar cell integrated snow melting sheet does not have a high thermal conductivity. If a material with high thermal conductivity is exposed on the front surface, back surface, edge, etc., heat generated by the heating element is preferentially transmitted to that portion, and only snow melting locally. In particular, if a material with high thermal conductivity is used for the exposed part other than the solar cell light receiving surface, a lot of heat is consumed in the snow melting of that part, and the snow melting on the solar cell light receiving surface becomes inefficient, and the power generation function is reduced. There is a risk that it cannot be fully utilized. Therefore, the thermal conductivity of the exposed portion other than the solar cell light-receiving surface is preferably 10 W / m / K or less, more preferably 1 W / m / K or less, and further preferably 0.5 W / m / K or less. On the other hand, the heat generated from the heating element may not be sufficiently transmitted even if the thermal conductivity is too low, so that it is preferably 0.01 W / m / K or more, more preferably 0.05 W / m / K.
Further, from the viewpoint of having an appropriate thermal conductivity, it is preferable that a resin material is used as the material exposed on the front surface, the back surface, the end portion and the like.

By forming the solar cell integrated snow melting sheet other than the solar cell element and the heating element with a resin material, it can be wound in a roll shape and can be easily transported and installed.
In particular, by using a solar cell-integrated snow melting sheet wound in a roll shape, the solar cell-integrated snow melting sheet can be spread and installed at an installation location such as on a roof, and the construction becomes easy.
That is, the second embodiment of the present invention is a method for installing a solar cell-integrated snow-melting sheet, comprising the step of spreading and installing a rolled solar cell-integrated snow-melting sheet at an installation location.
The installation location is usually a roof, but is not limited to this and can be installed on slopes, road surfaces, and stairs.
The roof as the installation location is not particularly limited. For example, metal roofs such as folding roofs, tiled roofs, sided roofs, corrugated roofs, vertical flat roofs, ant hanging roofs, natural roofs, etc. Examples include slate, slate roof using makeup slate, and tile roof using clay tile. Since such a solar cell integrated snow melting sheet has flexibility, it can follow the unevenness of the roof structure. In the case of an inflexible solar cell-integrated snow-melting sheet, the load applied to the sheet during snow accumulation differs depending on the unevenness of the ground, so that a portion where the load is concentrated may occur and may be damaged. If it is flexible enough to follow the unevenness of the roof structure, there is no concentration of load and the risk of breakage is small.

The solar cell-integrated snow melting sheet is lightweight and flexible, and does not require a large facility such as a gantry for installation. For example, the method of installation on the roof can be by a simple fixture. To illustrate a specific method, a simple fixture is installed on the roof, fixed with a hook-and-loop fastener (magic tape (registered trademark)), fixed with screws, fixed with a rope, fixed with a band. , Etc. In addition, fixing by pressing the solar cell integrated snow melting sheet with a metal rod, wire, etc., passing through the solar cell integrated snow melting sheet and screwing it directly to the roof, fixing to the roof with adhesive or adhesive, etc. Can be mentioned. Any of the known methods can be applied.
Also, when installing, between the solar cell integrated snow melting sheet and the roof, heat insulating material to prevent the heat generated from the heating element from escaping to the roof side, cushioning material to prevent damage due to the roof projections, etc. May be installed.

In the solar cell-integrated snow melting sheet according to the present embodiment, electricity generated by the solar cell can be taken out by a collecting wire connected to the solar cell. A publicly known method is applied about installation of a current collection line. The connection destination of the extracted electricity is not particularly limited. For example, it may be connected to a system power supply via an inverter or may be connected to a storage battery. In addition, the heating element is electrically connected to wiring for supplying electricity, and may be supplied with electricity from an external power source or a storage battery, and a part of the electricity generated by the solar cell is supplied to the heating element. You can also. Therefore, the collector circuit of the solar cell and the wiring of the heating element may be the same circuit that is electrically connected, or may be another circuit that is not electrically connected.

Hereinafter, specific embodiments will be described in more detail with reference to the drawings. However, it is needless to say that the present invention is not limited to the specific embodiments illustrated below.
<Embodiment 1>
FIG. 1 is a schematic view showing an embodiment of a solar cell integrated snow melting sheet according to the present invention.
The solar cell-integrated snow melting sheet 10a is a flexible solar cell, and is embedded in a sealing material layer 4a made of EVA between a surface protective layer 1a made of ETFE and a back surface protective layer 5a made of ETFE. The solar cell element 2 made of amorphous silicon and the heating element 3 made of conductive fibers are laminated. That is, a surface protective layer, a solar cell element, and a heating element are provided in this order, and the solar cell element and the heating element are sealed with a sealing material.
Although the solar cell element 2a is an amorphous silicon solar cell element, it is not particularly limited as long as the flexibility of the solar cell of this embodiment is not impaired. As the planar heating element, a flexible heating element can be used in addition to the heating element composed of a fiber coated with carbon nanotubes on a film.
The solar cell integrated snow melting sheet according to the present embodiment includes the heating element 3a, so that it is possible to melt the snow that has fallen and accumulated, and the power generation function of the solar cell is not hindered.

  Moreover, since the members other than the solar cell element 2a are made of a resin material, the solar cell integrated snow melting sheet 10a is excellent in flexibility and can be transported while being wound in a roll shape. Therefore, when installing on the roof, it is not necessary to replace the whole roofing material as in the past, and it is transported on the roof, spread at a desired position, and fixed to the roof using a simple fixing tool. Installation is possible.

<Embodiments 2 and 3>
2 and 3 are schematic views showing another embodiment of the solar cell integrated snow melting sheet according to the present invention.
In the solar cell integrated snow melting sheet 10b of FIG. 2, the sealing material layer is divided into two layers, a layer embedding the solar cell element 2b and a layer embedding the planar heating element 3b, respectively. It has an insulating layer 6b. The insulating layer 6b is made of ETFE. That is, it has a structure having a surface protective layer, a solar cell element, and a heating element in this order, and an insulating layer between the solar cell element and the heating element. Moreover, the solar cell element is sealed with a sealing material.
In the solar cell-integrated snow melting sheet 10b, since the solar cell element 2b and the planar heating element 3b are insulated by the insulating layer 6b, the electricity generated by the solar cell element 2b is other than the current collector (not shown). Can be prevented from going outside.

In the solar cell-integrated snow melting sheet 10c of FIG. 3, the sealing material layer is divided into two layers, a layer for embedding the solar cell element 2c and a layer for embedding the planar heating element 3c, respectively. An adhesive layer 7c and a reinforcing layer 8c are provided.
The reinforcing layer 8c is made of polyethylene terephthalate (PET), and the reinforcing layer on the solar cell element 2c side protects the solar cell element 2a from physical impact from the outside, and is a solar cell due to thermal contraction stress generated when the outside air temperature decreases. It has a function of preventing damage to the element 2c.
The reinforcing layer on the surface heating element 3c side protects the heating element from physical impact from the outside, and the sheet heating element 3c is disconnected due to heat shrinkage stress generated when the outside air temperature is lowered, and the heating function is lost. Has a function to prevent.

  Although specific embodiments have been described above, the solar cell-integrated snow melting sheet of the present invention can be appropriately modified or added with a layer not described unless contrary to the spirit of the present invention.

10a, 10b, 10c Solar cell integrated snow melting sheets 1a, 1b, 1c Surface protective layers 2a, 2b, 2c Solar cell elements 3a, 3b, 3c Planar heating elements 4a, 4b, 4c Sealing material layers 5a, 5b, 5c Back surface protective layer 6b Insulating layer 7c Adhesive layer 8c Reinforcing layer

Claims (10)

  A solar cell integrated snow melting sheet having a surface protective layer, a solar cell element, and a heating element in this order and having flexibility.   The solar cell-integrated snow melting sheet according to claim 1, wherein the solar cell element and the heating element have a structure sealed with a sealing material, and the surface of the solar cell element side of the structure has a surface protective layer. .   The solar cell integrated snow melting sheet according to claim 1, further comprising an insulating layer between the solar cell element and the heating element.   The solar cell integrated snow melting sheet according to claim 3, wherein the solar cell element is sealed with a sealing material.   The solar cell integrated snow melting sheet according to any one of claims 1 to 4, wherein the solar cell element is a thin film type solar cell element.   The solar cell-integrated snow melting sheet according to any one of claims 1 to 5, wherein the heating element is a planar heating element and is made of conductive fibers.   Furthermore, the solar cell integrated snow melting sheet of any one of Claims 1-6 which has a back surface protective layer.   The solar cell-integrated snow-melting sheet according to any one of claims 1 to 7, wherein a member constituting a layer of the solar cell-integrated snow-melting sheet other than the solar cell element and the heating element is made of a resin material.   The solar cell-integrated snow-melting sheet according to claim 8, which is wound in a roll shape.   The installation method of the solar cell integrated snow-melting sheet which has a step which expands and installs the roll-shaped solar cell integrated snow melting sheet of Claim 9 in an installation place.

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