Flexible solar panel installation structure

Abstract

This provides a highly safe installation structure for flexible solar cells, even when exposed to strong winds. [Solution] An installation structure for a flexible solar cell comprising: an installation surface having a continuous protrusion in one direction; a flexible solar cell disposed on the surface of the installation surface having the protrusion; a fixing member that sandwiches and fixes the flexible solar cell on the protrusion; and a deformable member disposed between the protrusion and the flexible solar cell, wherein the deformable member is sandwiched together with the flexible solar cell between the fixing member and the protrusion, and the compressive strength of the deformable member is 0.5 MPa or more and 400 MPa or less.

Description

Technical Field

[0001] The present invention relates to an installation structure of a flexible solar cell.

Background Art

[0002] Conventionally, rigid solar cell panels made of silicon semiconductors have been widely used as solar cells. However, since conventional solar cell panels have a certain weight, they cannot be installed on some structures with low load-bearing capacity, or even on an installation surface where they can be installed, but on parts with low load-bearing capacity on the installation surface, they cannot be installed, so there is a problem that the area of the installation surface cannot be effectively utilized. Therefore, in recent years, flexible solar cells based on heat-resistant polymer materials such as polyimide and polyester, or metal foils have been attracting attention. Flexible solar cells have advantages such as ease of transportation and construction due to thinning and weight reduction, and strong resistance to impact. Flexible solar cells using flexible solar cells can be installed along the installation surface even on an installation surface with unevenness. (For example, Patent Document 1)

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When installing flexible solar cells on an uneven surface, the method of installing them along the contours of the surface, as described in Patent Document 1, is effective from the standpoint of maximizing the power generation area. However, while this method of installing flexible solar cells along the contours of the surface increases the power generation area, it has the problem of poor maintainability, such as the replacement of the flexible solar cells. Typically, the building materials and structures that serve as the installation surface for flexible solar cells have a longer lifespan than the flexible solar cells themselves, so it is expected that the flexible solar cells will need to be replaced when they reach the end of their lifespan. In this case, if the flexible solar cells are installed along the contours, the replacement work becomes complicated, reducing maintainability. Therefore, a method of installing flexible solar cells by stretching them over the recesses has been considered to facilitate maintenance. However, when flexible solar cells are installed by stretching them over the recesses, when wind blows into the space between the flexible solar cell and the recess, deformation such as bending and vibration occurs in the flexible solar cell. Repeated deformation can lead to damage to the flexible solar cell, breakage of wiring, and damage to the installation surface. One possible solution to this problem is to firmly fix the flexible solar cells in place. While this would reduce deformation caused by wind, the flexible solar cells could still be damaged, and there is a need for a flexible solar cell installation structure that offers greater safety against strong winds.

[0005] The present invention aims to provide a highly safe installation structure for flexible solar cells, even when exposed to strong winds. [Means for solving the problem]

[0006] The present invention is an installation structure for a flexible solar cell, comprising: an installation surface having a convex portion continuous in one direction; a flexible solar cell disposed on the surface of the installation surface having the convex portion; a fixing member that secures the flexible solar cell by sandwiching it between the convex portion; and a deformable member disposed between the convex portion and the flexible solar cell, wherein the deformable member is sandwiched together with the flexible solar cell between the fixing member and the convex portion, and the compressive strength of the deformable member is 0.5 MPa or more and 400 MPa or less. The present invention will be described in detail below. [Effects of the Invention]

[0007] According to the present invention, it is possible to provide a flexible solar cell installation structure that offers high safety even when exposed to strong winds. [Brief explanation of the drawing]

[0008] [Figure 1] This is a cross-sectional view of a conventional flexible solar cell installed on a mounting surface having a protrusion. [Figure 2] This is a schematic cross-sectional view showing an example of the installation structure for the flexible solar cell of the present invention. [Figure 3] This is a schematic cross-sectional view illustrating yet another example of the installation structure for the flexible solar cell of the present invention. [Figure 4] This is a schematic cross-sectional view showing an example of a flexible solar cell and an easily deformable member in the installation structure of the flexible solar cell of the present invention. [Figure 5] This is a top view of Figure 4. [Figure 6] This is a schematic cross-sectional view showing a further example of a flexible solar cell and an easily deformable member in the installation structure of the flexible solar cell of the present invention. [Figure 7] This is a schematic cross-sectional view showing a further example of a flexible solar cell and an easily deformable member in the installation structure of the flexible solar cell of the present invention. [Modes for carrying out the invention]

[0009] The present invention will be described in more detail below with reference to specific embodiments, but the present invention is not limited to these embodiments.

[0010] (Embodiment 1) Figure 1 shows a cross-sectional view of a conventional flexible solar cell installed on a mounting surface with a protrusion. As shown in Figure 1, when installing a conventional flexible solar cell 1 on an installation surface having protrusions 2 such as a corrugated metal roof, the flexible solar cell 1 is fixed by sandwiching the fixing member 3 between the protrusions 2 while the flexible solar cell 1 is stretched, from the viewpoint of maintainability. On the other hand, with the conventional installation structure, the flexible solar cell 1 can deform due to wind, and repeated deformation can damage the flexible solar cell 1. Also, if the flexible solar cell 1 is blown away by strong winds, the protrusions 2 may be damaged. One way to solve this problem is to suppress the deformation of the flexible solar cell 1 by fixing the fixing member 3 with strong force after the flexible solar cell 1 is stretched tightly. However, even if the flexible solar cell 1 is firmly fixed, although deformation due to wind is suppressed, the flexible solar cell 1 can still be damaged. Therefore, the inventors investigated the cause of damage to the flexible solar cell 1 when it is firmly fixed and found that the cause is the concentration of force on a specific part of the flexible solar cell 1. When wind blows onto a firmly fixed flexible solar cell 1, a force from the wind is applied to the contact part between the flexible solar cell 1 and the fixing member 3. On the other hand, since the flexible solar cell 1 is also subjected to tension during fixing, a stronger force is applied to the contact area mentioned above. As a result, although the flexible solar cell 1 does not deform, it is prone to damage while fixed. Furthermore, while damage to the flexible solar cell 1 poses a risk of electrical leakage, a firmly fixed flexible solar cell 1 deforms little and appears normal at first glance, making it difficult to notice damage. Consequently, suppressing deformation to prevent damage to the flexible solar cell sometimes actually increases the risk.

[0011] Figures 2 and 3 show schematic cross-sectional views illustrating an example of the installation structure for the flexible solar cell of the present invention. As shown in Figure 2, the installation structure for the flexible solar cell of the present invention comprises an installation surface having a convex portion 2 that is continuous in one direction, a flexible solar cell 1 positioned on the surface of the installation surface having the convex portion 2, a fixing member 3 that secures the flexible solar cell 1 by sandwiching it between the convex portion 2, and a deformable member 4 positioned between the convex portion 2 and the flexible solar cell 1. The deformable member 4 is sandwiched between the fixing member 3 and the convex portion 2 together with the flexible solar cell 1. By providing the easily deformable member 4, when strong winds apply a strong force to the fixing part of the flexible solar cell 1, the easily deformable member 4 deforms and shifts in the planar direction (a direction perpendicular to the thickness direction), and the position of the flexible solar cell 1 also shifts accordingly. As a result, a large force is not applied to one place on the flexible solar cell 1 for a long period of time, so that the deformation of the flexible solar cell 1 due to strong winds is limited to a certain range and damage is suppressed. In addition, since the easily deformable member 4 acts as a cushion by being sandwiched between the flexible solar cell 1 and the protrusion 2, the force from the fixing member 3 and the force from the wind are appropriately distributed, so that damage to the flexible solar cell 1 is further suppressed. Furthermore, by sandwiching the easily deformable member 4 between the protrusion 2 and the flexible solar cell 1, the frictional force and impact transmitted from the flexible solar cell 1 to the protrusion are reduced, so even if the flexible solar cell 1 is blown away, damage to the protrusion 2 can be suppressed.

[0012] On the other hand, using the easily deformable member 4 reduces deformation of the flexible solar cell and damage to the mounting surface due to strong winds compared to fixing it with conventional strength without using the easily deformable member 4. However, because the flexible solar cell 1 is structured to shift position when exposed to strong winds, the fixing force is inevitably reduced compared to when the flexible solar cell 1 is firmly fixed. Nevertheless, even if the flexible solar cell 1 is blown away by an unbearable strong wind, because the flexible solar cell 1 is light and flexible, the severity of damage to the surrounding environment and human health is small. Furthermore, as mentioned above, damage and scattering of the mounting surface (protrusion 2) are unlikely, making it highly safe from the viewpoint of the mounting surface. In fact, it is more dangerous if the flexible solar cell 1 is firmly fixed and damaged with little deformation. Therefore, by deliberately setting the fixing force to such an extent that it will be blown away when exposed to excessively strong winds, overall safety can be enhanced. The easily deformable member 4 only needs to be placed at least between the protrusion 2 and the flexible solar cell 1, but from the viewpoint of appropriately distributing the force from the fixing member 3 and further reducing damage to the flexible solar cell 1, it may also be placed between the flexible solar cell 1 and the fixing member 3, as shown in Figure 3. Furthermore, the easily deformable member 4 may be independent of the flexible solar cell 1 or may be integrated with it.

[0013] Furthermore, Figure 4 shows a schematic cross-sectional view illustrating an example of a flexible solar cell and a deformable member in the installation structure of the flexible solar cell of the present invention, and Figure 5 shows a top view of Figure 4. Figures 4 and 5 show the arrangement of the deformable member relative to the flexible solar cell before installation. As shown in Figures 4 and 5, the flexible solar cell 1 has a structure in which a power generation section 11, a sealing layer 12 that seals the entire power generation section, a front sheet 13 on the outermost surface on the light-receiving side, and a back sheet 14 on the outermost surface on the installation side are laminated together. In addition, the non-power generation section where no power generation section is formed serves as the fixing section to the installation surface, and a deformable member 4 is arranged over the entire area in the fixing direction. If the flexible solar cell 1 has only one power generation section 11, the non-power generation section at the edge of the flexible solar cell 1 becomes the fixing section.

[0014] Examples of the installation surface having the convex portions continuous in the above-mentioned one direction include vertical roofs such as folded-plate roofs and tile roofs. The installation surface may or may not have a gradient, but it is preferably provided with a gradient. Since the arrangement of the flexible solar cells can be optimized when the installation surface has a gradient, the power generation efficiency can be further enhanced.

[0015] The material of the installation surface is not particularly limited, and examples thereof include metals such as steel, aluminum alloy, stainless steel, nickel alloy, and copper alloy, rigid plastics such as vinyl chloride, polycarbonate, acrylic, polypropylene, ABS resin, and AS resin, rubber, ceramic, or composite materials thereof.

[0016] The power generation unit is composed of a base material, an electrode, a counter electrode, a photoelectric conversion layer, an electron transport layer, a hole transport layer, etc., and has at least an electrode, a photoelectric conversion layer, and a counter electrode. In this specification, the layer not only means a layer having a clear boundary but also means a layer having a concentration gradient in which the contained elements gradually change. The elemental analysis of the layer can be performed, for example, by performing FE-TEM / EDS line analysis measurement of the cross section of the solar cell to confirm the elemental distribution of specific elements. Further, in this specification, the layer not only means a flat thin film-like layer but also means a layer that can form a complicated intertwined structure together with other layers.

[0017] Examples of the base material include resin films made of polyimide and polyester-based heat-resistant polymers, metal foils, thin plate glasses, etc. Among them, a PET resin film is preferable from the viewpoints of cost and heat resistance.

[0018] The materials of the above-mentioned electrode and counter electrode are not particularly limited. For example, FTO (fluorine-doped tin oxide), ITO (tin-doped indium oxide), AZO (aluminum zinc oxide), IZO (indium zinc oxide), GZO (gallium zinc oxide), sodium, sodium-potassium alloy, lithium, magnesium, aluminum, magnesium-silver mixture, magnesium-indium mixture, aluminum-lithium alloy, Al / Al2O3 mixture, Al / LiF mixture, etc. can be mentioned. Also, gold, silver, titanium, molybdenum, tantalum, tungsten, carbon, nickel, chromium, etc. can be mentioned. These materials may be used alone or two or more of them may be used in combination.

[0019] The thickness of the above-mentioned electrode and counter electrode is not particularly limited, but the preferable lower limit is 10 nm and the preferable upper limit is 1000 nm. If the above thickness is 10 nm or more, the function as an electrode can be exhibited and the resistance can be suppressed. If the above thickness is 1000 nm or less, the light transmittance can be further improved. The more preferable lower limit of the thickness of the above-mentioned electrode and counter electrode is 50 nm, and the more preferable upper limit is 500 nm.

[0020] Examples of the photoelectric conversion material constituting the above-mentioned photoelectric conversion layer include organic-inorganic perovskite compounds, organic semiconductors, etc. Among them, since the photoelectric conversion efficiency is high and a large-area flexible solar cell can be manufactured at low cost, it is preferable that the above-mentioned photoelectric conversion layer contains an organic-inorganic perovskite compound. The organic-inorganic perovskite compound is a compound represented by the general formula AMX (where A is an organic base compound and / or an alkali metal, M is a lead or tin atom, and X is a halogen atom). A solar cell containing such an organic-inorganic perovskite compound is also called an organic-inorganic hybrid solar cell.

[0021] The above A is an organic base compound and / or an alkali metal. The above organic base compounds specifically include, for example, methylamine, ethylamine, propylamine, butylamine, pentylamine, hexylamine, dimethylamine, diethylamine, dipropylamine, dibutylamine, dipentylamine, dihexylamine, trimethylamine, triethylamine, tripropylamine, tributylamine, tripentylamine, trihexylamine, ethylmethylamine, methylpropylamine, butylmethylamine, methylpentylamine, hexylmethylamine, ethylpropylamine, ethylbutylamine, formamidine, acetamidine, guanidine, imidazole, azole, pyrrole, aziridine, azirine, azetidine, azeto, azole, imidazoline, carbazole and their ions (e.g., methylammonium (CH3NH3)) and phenethylammonium. Among these, methylamine, ethylamine, propylamine, butylamine, pentylamine, hexylamine, formamidine, acetamidine and their ions, and phenethylammonium are preferred, and methylamine, ethylamine, propylamine, formamidine and their ions are more preferred. Examples of the alkali metals mentioned above include lithium, sodium, potassium, rubidium, and cesium.

[0022] The above M is a metal atom, which is either lead or tin. These metal atoms may be used individually or in combination of two or more types.

[0023] The above X is a halogen atom, and examples of halogen atoms include chlorine, bromine, iodine, sulfur, and selenium. These halogen atoms may be used individually or in combination of two or more. By including a halogen in the structure, the above organic-inorganic perovskite compound becomes soluble in organic solvents, making it possible to apply it to inexpensive printing methods and the like. In particular, X is preferably iodine because it narrows the energy band gap of the above organic-inorganic perovskite compound.

[0024] The above organic-inorganic perovskite compound preferably has a cubic crystal structure in which a metal atom M is located at the body center, an organic base compound or alkali metal A is located at each vertex, and a halogen atom X is located at the face center. Although the details are not clear, it is presumed that having the above structure allows the orientation of octahedra within the crystal lattice to be easily changed, thereby increasing the electron mobility in the organic-inorganic perovskite compound and improving the photoelectric conversion efficiency of the solar cell.

[0025] The above organic-inorganic perovskite compound is preferably a crystalline semiconductor. A crystalline semiconductor is a semiconductor in which the X-ray scattering intensity distribution can be measured and a scattering peak can be detected. The crystalline nature of the organic-inorganic perovskite compound increases the electron mobility within it, thereby improving the photoelectric conversion efficiency of the flexible solar cell.

[0026] Furthermore, the degree of crystallinity can be evaluated as an indicator of crystallization. The degree of crystallinity can be determined by fitting the scattering peaks originating from the crystalline portion and the halos originating from the amorphous portion, as detected by X-ray scattering intensity distribution measurement, calculating the integral of each intensity, and then calculating the ratio of the crystalline portion to the whole. The preferred lower limit for the crystallinity of the above organic-inorganic perovskite compound is 30%. When the crystallinity is 30% or higher, the electron mobility in the organic-inorganic perovskite compound increases, improving the photoelectric conversion efficiency of the solar cell. A more preferred lower limit for the crystallinity is 50%, and an even more preferred lower limit is 70%. Furthermore, methods for increasing the crystallinity of the above-mentioned organic-inorganic perovskite compounds include, for example, thermal annealing, irradiation with high-intensity light such as lasers, and plasma irradiation.

[0027] The above-mentioned photoelectric conversion layer may further contain an organic semiconductor or an inorganic semiconductor in addition to the organic-inorganic perovskite compound, as long as it does not impair the effects of the present invention. The organic semiconductor or inorganic semiconductor referred to herein may function as a hole transport layer or an electron transport layer. Examples of the above-mentioned organic semiconductors include compounds having a thiophene skeleton such as poly(3-alkylthiophene). Other examples include conductive polymers having a poly(p-phenylenevinylene) skeleton, polyvinylcarbazole skeleton, polyaniline skeleton, polyacetylene skeleton, etc. Furthermore, examples include compounds having a porphyrin skeleton such as a phthalocyanine skeleton, naphthalocyanine skeleton, pentacene skeleton, benzoporphyrin skeleton, spirobifluorene skeleton, etc., as well as carbon-containing materials such as carbon nanotubes, graphene, and fullerene, which may be surface-modified.

[0028] Examples of the inorganic semiconductors mentioned above include titanium dioxide, zinc oxide, indium oxide, tin oxide, gallium oxide, tin sulfide, indium sulfide, zinc sulfide, CuSCN, Cu2O, CuI, MoO3, V2O5, WO3, MoS2, MoSe2, and Cu2S.

[0029] When the photoelectric conversion layer includes the organic-inorganic perovskite compound and the organic semiconductor or inorganic semiconductor, it may be a laminate formed by stacking thin-film organic semiconductor or inorganic semiconductor portions and thin-film organic-inorganic perovskite compound portions, or it may be a composite film formed by combining the organic semiconductor or inorganic semiconductor portion and the organic-inorganic perovskite compound portion. A laminate is preferred in terms of ease of manufacture, while a composite film is preferred in terms of being able to improve the charge separation efficiency in the organic semiconductor or inorganic semiconductor.

[0030] The thickness of the thin film-like organic-inorganic perovskite compound portion described above has a preferred lower limit of 5 nm and a preferred upper limit of 5000 nm. If the thickness is 5 nm or more, sufficient light absorption becomes possible, and the photoelectric conversion efficiency increases. If the thickness is 5000 nm or less, the occurrence of regions where charge separation is not possible can be suppressed, leading to an improvement in photoelectric conversion efficiency. A more preferred lower limit for the thickness is 10 nm, a more preferred upper limit is 1000 nm, an even more preferred lower limit is 20 nm, and an even more preferred upper limit is 500 nm.

[0031] When the photoelectric conversion layer is a composite film formed by combining an organic semiconductor or inorganic semiconductor portion with an organic-inorganic perovskite compound portion, the preferred lower limit of the thickness of the composite film is 30 nm, and the preferred upper limit is 3000 nm. If the thickness is 30 nm or more, sufficient light can be absorbed, and the photoelectric conversion efficiency will be high. If the thickness is 3000 nm or less, the charge can reach the electrodes more easily, and the photoelectric conversion efficiency will be high. A more preferred lower limit of the thickness is 40 nm, a more preferred upper limit is 2000 nm, an even more preferred lower limit is 50 nm, and an even more preferred upper limit is 1000 nm.

[0032] The method for forming the above-mentioned photoelectric conversion layer is not particularly limited and includes methods such as vacuum deposition, sputtering, vapor deposition (CVD), electrochemical deposition, and printing. In particular, by employing the printing method, solar cells that can exhibit high photoelectric conversion efficiency can be easily formed over a large area. Examples of printing methods include spin coating and casting, and methods using the printing method include roll-to-roll.

[0033] The above-mentioned power generation unit may have an electron transport layer between the electrode acting as the cathode or the counter electrode and the photoelectric conversion layer. The material of the electron transport layer is not particularly limited, and examples include N-type conductive polymers, N-type low molecular weight organic semiconductors, N-type metal oxides, N-type metal sulfides, alkali metal halides, alkali metals, surfactants, etc. Specifically, examples include cyano group-containing polyphenylene vinylene, boron-containing polymers, vasocuproin, vasophenanthrene, hydroxyquinolinatoaluminum, oxadiazole compounds, benzimidazole compounds, naphthalenetetracarboxylic acid compounds, perylene derivatives, phosphine oxide compounds, phosphine sulfide compounds, fluoro group-containing phthalocyanines, titanium dioxide, zinc oxide, indium oxide, tin oxide, gallium oxide, tin sulfide, indium sulfide, zinc sulfide, etc.

[0034] The electron transport layer described above may consist only of a thin-film electron transport layer, but it is preferable to include a porous electron transport layer. In particular, when the photoelectric conversion layer is a composite film formed by combining an organic semiconductor or inorganic semiconductor portion with an organic-inorganic perovskite compound portion, a more complex composite film (a more intricately interwoven structure) can be obtained, and the photoelectric conversion efficiency is higher, so it is preferable that the composite film is fabricated on a porous electron transport layer.

[0035] The preferred lower limit for the thickness of the electron transport layer is 1 nm, and the preferred upper limit is 2000 nm. If the thickness is 1 nm or more, holes can be sufficiently blocked. If the thickness is 2000 nm or less, it will not be a resistance during electron transport, and the photoelectric conversion efficiency will be high. A more preferred lower limit for the thickness of the electron transport layer is 3 nm, a more preferred upper limit is 1000 nm, an even more preferred lower limit is 5 nm, and an even more preferred upper limit is 500 nm.

[0036] The above-mentioned power generation unit may have a hole transport layer between the electrodes or counter electrodes that make up the anode and cathode and the photoelectric conversion layer. The material of the hole transport layer is not particularly limited, and the hole transport layer may be made of an organic material. Examples of materials for the hole transport layer include P-type conductive polymers, P-type low molecular weight organic semiconductors, P-type metal oxides, P-type metal sulfides, surfactants, etc. Specifically, examples include compounds having a thiophene skeleton such as poly(3-alkylthiophene). Also, examples include conductive polymers having a triphenylamine skeleton, poly(p-phenylenevinylene) skeleton, polyvinylcarbazole skeleton, polyaniline skeleton, polyacetylene skeleton, etc. Furthermore, examples include compounds having a phthalocyanine skeleton, naphthalocyanine skeleton, pentacene skeleton, benzoporphyrin skeleton or other porphyrin skeletons, spirobifluorene skeleton, etc., molybdenum sulfide, tungsten sulfide, copper sulfide, tin sulfide, etc., fluoro group-containing phosphonic acid, carbonyl group-containing phosphonic acid, CuSCN, CuI, etc.

[0037] The shape of the flexible solar cell described above is not particularly limited to a sheet shape, and examples include circular, elliptical, polygonal, etc., which can be appropriately determined according to the installation surface.

[0038] The flexible solar cell described above preferably has a bending strength of 10 MPa or more, more preferably 20 MPa or more, and even more preferably 50 MPa or more. Having the lower limit of the bending strength of the flexible solar cell within this range further improves its handling. Furthermore, the flexible solar cell preferably has a bending strength of 200 MPa or less, more preferably 150 MPa or less, and even more preferably 50 MPa or less. Having the upper limit of the bending strength of the flexible solar cell within this range further improves its flexibility. The bending strength of the flexible solar cell can be measured by a method compliant with JIS K7171.

[0039] The flexible solar cell described above preferably has a flexural modulus of 100 MPa or more, and more preferably 500 MPa or more. Having the lower limit of the flexural modulus of the flexible solar cell within this range further improves its handling. Furthermore, the flexible solar cell preferably has a flexural modulus of 10,000 MPa or less, and more preferably 5,000 MPa or less. Having the upper limit of the flexural modulus of the flexible solar cell within this range further improves its flexibility. The flexural modulus of the flexible solar cell can be measured by a method compliant with JIS K7171.

[0040] The structure of the fixing member described above is not particularly limited as long as it can be fixed to the protrusion while sandwiching the flexible solar cell. Examples include a pipe-shaped structure with a C-shaped cross-section, or a structure consisting of a part that clamps one side of the protrusion and a part that clamps the other side, with these parts connected by screws, hinges, etc.

[0041] The material of the fixing member described above only needs to have sufficient rigidity to fix the flexible solar cell. Examples include metals such as steel, aluminum alloy, stainless steel, nickel alloy, and copper alloy; hard plastics such as polyvinyl chloride, polycarbonate, acrylic, polypropylene, ABS resin, AS resin, and PPS resin; rubber; ceramics; or composite materials thereof. In particular, it is preferable to use a flame-retardant material so as to suppress the spread of fire to the installation surface in the event of a fire occurring in the flexible solar cell. Here, a flame-retardant material means a material that has a flame retardancy of V-0 or higher in the UL94 vertical combustion test.

[0042] The length of the fixing member is not particularly limited as long as it is equal to or greater than the length of the side of the flexible solar cell that is clamped. In particular, from the viewpoint of making installation easier by allowing for some leeway in positioning and from the viewpoint of miniaturizing by keeping the length down, the length of the fixing member is preferably 1 cm or more, more preferably 5 cm or more, preferably 15 cm or less, and most preferably 10 cm or less than the length of the side of the flexible solar cell that is clamped.

[0043] The above-mentioned easily deformable member has a compressive strength of 0.5 MPa or more and 400 MPa or less. The compressive strength of the above-mentioned easily deformable member is preferably 0.5 MPa or more, allowing the flexible solar cell to be firmly fixed under normal conditions, and is preferably 400 MPa or less, allowing it to deform in the planar direction when strong winds blow in, thereby suppressing damage to the flexible solar cell. The compressive strength of the above-mentioned easily deformable member is preferably 1 MPa or more, more preferably 5 MPa or more, even more preferably 10 MPa or more, even more preferably 25 MPa or more, very preferably 50 MPa or more, and particularly preferably 150 MPa or more. Furthermore, the compressive strength of the above-mentioned easily deformable member is preferably 350 MPa or less, more preferably 300 MPa or less, and even more preferably 250 MPa or less. The compressive strength of the above-mentioned easily deformable member can be measured according to the following JIS standard measurement method depending on the type of material. JIS K 7171: Compression Test Method for Plastics JIS K 6254: Method for testing the compression of rubber JIS Z 2241: Compression Test Method for Metallic Materials JIS R 1608: Compression Test Method for Fine Ceramics JIS K 7076: Compression Test Method for Fiber-Reinforced Plastics JIS A 1108: Method for testing the compressive strength of concrete

[0044] The thickness of the easily deformable member is not particularly limited, but from the viewpoint of balancing the fixing force of the flexible solar cell with the amount of deformation of the easily deformable member, it is preferably 300 μm or more, more preferably 450 μm or more, preferably 1000 μm or less, and more preferably 700 μm or less.

[0045] The material of the easily deformable member described above is not particularly limited as long as it can be deformed in the planar direction when a strong force is applied. Examples include resin materials such as silicone resin, fibrous materials such as glass wool and steel wool, glass fiber composite tent fabric and composite materials thereof. In particular, the easily deformable member is preferably made of a flame-retardant material so as to suppress the spread of fire to the installation surface in the event that the flexible solar cell catches fire, and is more preferably made of a fibrous flame-retardant material because it has excellent long-term durability. Examples of the fibrous flame-retardant material described above include glass wool and tent fabric.

[0046] (Embodiment 2) Figure 6 shows a schematic cross-sectional view illustrating another example of a flexible solar cell and an easily deformable member in the installation structure of the flexible solar cell of the present invention. The installation structure for the flexible solar cell in Embodiment 2 consists of multiple flexible solar cells 1, each comprising a power generation unit 11, a sealing layer 12, a front sheet 13, and a back sheet 14, arranged at regular intervals on a sheet-like member 5. The spaces between the flexible solar cells 1 on the sheet-like member 5 are fixed to protrusions on the installation surface, and easily deformable members 4 are provided therein. By arranging the flexible solar cells 1 on the sheet-like member 5, handling and ease of installation are improved compared to installing the flexible solar cells 1 individually, and the design can be easily adapted to the area and shape of the installation surface.

[0047] The above-mentioned sheet-like member is not particularly limited as long as it is flexible, and examples include resin sheets, fiber-reinforced sheets, metal sheets, or composite materials thereof. In particular, it is preferable that the above-mentioned sheet-like member be made of a flame-retardant material, as this makes it difficult for the fire to spread to the installation surface even if the flexible solar cell catches fire.

[0048] The thickness of the sheet-like member described above is not particularly limited, but from the viewpoint of ensuring strength, it is preferably 300 μm or more, more preferably 450 μm or more, and even more preferably 500 μm or more. Furthermore, from the viewpoint of ensuring flexibility, it is preferably 5000 μm or less, more preferably 3000 μm or less, and even more preferably 1000 μm or less.

[0049] (Embodiment 3) Figure 7 shows a schematic cross-sectional view illustrating another example of a flexible solar cell and an easily deformable member in the installation structure of the flexible solar cell of the present invention. In the installation structure of the flexible solar cell of Embodiment 3, the backsheet 14 plays the role of the sheet-like member 5 of Embodiment 2, and a flexible solar cell 1 sharing the backsheet 14 is formed by stacking multiple power generation units 11, sealing layers 12, and front sheets 13 on a single backsheet 14. Also, similar to Embodiment 2, the space between the stacked structures consisting of the power generation units 11, sealing layers 12, and front sheets 13 is the portion fixed to the protrusions on the installation surface, and the easily deformable member 4 is positioned there. Furthermore, in Embodiment 3, a frame member 6 is arranged in contact with the sealing layer 12 and surrounding at least the entire side surface of the sealing layer 12. By providing such a frame member 6, the area around the power generation unit 11 can be reinforced, and the intrusion of moisture from the side surface of the sealing layer 12 can be suppressed, thereby further increasing durability. Note that the ends of the frame member 6 may overlap with the light-receiving surface of the front sheet 13, and a part of it may overlap with the power generation unit 11, but it is preferable that it does not overlap with the portion fixed to the installation surface.

[0050] The material of the frame member described above is not particularly limited as long as it has a certain degree of strength and excellent water vapor barrier performance, for example, aluminum, stainless steel, etc. Among these, aluminum is preferred because it is lightweight.

[0051] The thickness of the frame member described above is not particularly limited, but from the viewpoint of balancing reinforcing performance, water vapor barrier performance and flexibility, it is preferably 30 μm or more, more preferably 500 μm or more, preferably 5000 μm or less, and even more preferably 3000 μm or less.

[0052] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0053] (Example 1) A glass fiber composite tent fabric was bonded to a flexible solar cell using an organic-inorganic perovskite compound as the photoelectric conversion layer, in the arrangement shown in Figures 4 and 5, as a deformable member. Next, the flexible solar cell was placed so that the center of the deformable member aligned with the seam (protrusion) of the corrugated metal roof, which was the installation surface. Then, while pulling the flexible solar cell, the deformable member was sandwiched between fixing members having a C-shaped pipe-like cross-section made of aluminum, thereby fixing the flexible solar cell to the cross-sectional shape shown in Figure 3. The compressive strength of the deformable member measured using the above method was found to be 250 MPa. Next, a strong wind test was conducted by applying a wind of 46 m / s for 5 minutes from the side of the installed solar power generation sheet (a cross-sectional direction perpendicular to the extension direction of the protrusions). Upon visual inspection of the flexible solar cells after the strong wind test, it was found that they were shifted and deformed, but not damaged.

[0054] (Comparative Example 1) The flexible solar cells were fixed to the corrugated metal roof in the same manner as in Example 1, except that easily deformable members were not used. Subsequently, a strong wind test was conducted in the same manner as in Example 1. Although the flexible solar cells did not deform, damage was observed at the contact points with the fixing members. [Industrial applicability]

[0055] According to the present invention, it is possible to provide a flexible solar cell installation structure that offers high safety even when exposed to strong winds. [Explanation of symbols]

[0056] 1. Flexible solar cells 11 Power Generation Department 12. Sealing layer 13 Front Seats 14 Backseat 2. Convex part 3 Fixing member 4. Easily deformable member 5 Sheet-like member 6 Frame members

Claims

1. An installation surface having a continuous protrusion in one direction, A flexible solar cell is disposed on the surface of the mounting surface having the protrusion, A fixing member for sandwiching and fixing the flexible solar cell on the protrusion, It has a deformable member disposed between the protrusion and the flexible solar cell, The easily deformable member is sandwiched together with the flexible solar cell between the fixing member and the protrusion. The compressive strength of the easily deformable member is 0.5 MPa or more and 400 MPa or less. A flexible solar cell installation structure characterized in that the thickness of the easily deformable member is 300 μm or more.

2. The installation structure for a flexible solar cell according to claim 1, characterized in that the easily deformable member is provided between the flexible solar cell and the fixing member at the portion sandwiched by the fixing member.

3. The installation structure for a flexible solar cell according to claim 1 or 2, wherein the easily deformable member is made of a flame-retardant material.

4. The installation structure for a flexible solar cell according to claim 3, wherein the flame-retardant material is a fibrous flame-retardant material.

5. The flexible solar cell has a bending strength of 10 MPa or more and 200 MPa or less, as described in claim 1 or 2, and is an installation structure for a flexible solar cell.

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