Perovskite solar cell

Abstract

To provide a perovskite solar cell capable of reducing the total amount of heat generation and suppressing deterioration in power generation efficiency.SOLUTION: A perovskite solar cell 100 includes a laminate 10 having a conductive layer 2 disposed on a substrate 1 and a solar cell 3 disposed on the conductive layer 2, and a protective layer 20 for protecting the laminate 10. The protective layer 20 includes a primary sealing layer 4 that seals the solar battery cells 3, a secondary sealing layer 6 that covers the laminate 10 and the primary sealing layer 4, and a first sheet 7 and a second sheet 8 that sandwich the secondary sealing layer 6. The secondary sealing layer 6 and the second sheet 8 are made of a material containing silicone as a main component.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to perovskite solar cells. [Background technology]

[0002] Perovskite solar cells, a type of solar cell that converts solar light energy into electrical energy, have attracted attention because they have higher energy conversion efficiency than other solar cells, are lightweight, etc. However, perovskite solar cells have the problem of being easily degraded by oxygen, water, etc., and various technologies have been proposed to address this problem (see, for example, Patent Document 1).

[0003] Patent Document 1 discloses a perovskite solar cell comprising: a barrier film formed on a substrate to prevent moisture from penetrating from the substrate; solar cells arranged on the barrier film; a primary sealing layer (sealing layer in Patent Document 1) that seals the solar cells and has gas barrier properties; a secondary sealing layer (adhesive layer in Patent Document 1) arranged to cover the solar cells and the primary sealing layer; and a first sheet (first substrate in Patent Document 1) and a second sheet (second substrate in Patent Document 1) that sandwich the secondary sealing layer. The second sheet is also referred to as a backsheet. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2020-188047 Summary of the Invention [Problem to be solved by the invention]

[0005] In perovskite solar cells such as those disclosed in Patent Document 1, ethylene vinyl acetate (EVA) and polyolefin elastomer (POE) are generally used as materials for the primary and secondary encapsulation layers. Furthermore, polytetrafluoroethylene (PTFE) and tetrafluoroethylene-ethylene copolymer (ETFE) are generally used as materials for the first sheet, and polyethylene terephthalate (PET) is generally used as a material for the secondary sheet.

[0006] Solar panels using perovskite solar cells can sometimes be installed on the walls of buildings, taking advantage of their lightweight characteristics. In such cases, the fire department in charge of the building may require the solar panels to have performance equivalent to that of non-combustible materials as defined by the Building Standards Act. To be certified as equivalent to a non-combustible material, the heat generated by each material used in the perovskite solar cell upon combustion must be small, and the total heat generated by the perovskite solar cell must be small. However, in the case of perovskite solar cells using the above-mentioned organic compounds, the total heat generated by the organic compounds upon combustion is large, making it difficult for solar panels using perovskite solar cells to be certified as equivalent to a non-combustible material. Therefore, it is difficult to install solar panels using perovskite solar cells on the walls of buildings, and there is room for improvement.

[0007] Furthermore, in general, in solar panels, as the panel temperature rises, the generated voltage decreases, and power generation efficiency also declines. To prevent this decline in power generation efficiency, it is necessary to adequately dissipate the heat generated during power generation in the solar cell to the outside of the solar panel. However, because the above-mentioned organic compounds have low thermal conductivity, perovskite solar cells using these organic compounds are unable to adequately dissipate the heat generated during power generation in the solar cell. Therefore, when a solar panel is constructed using perovskite solar cells using these organic compounds, it is difficult to prevent a decline in power generation efficiency during panel use, and there is room for improvement in this regard as well.

[0008] Therefore, there is a demand for perovskite solar cells that can reduce the total amount of heat generated and suppress a decrease in power generation efficiency. [Means for solving the problem]

[0009] One embodiment of a perovskite solar cell according to the present disclosure comprises a laminate having an electrically conductive layer disposed on a substrate and a solar cell disposed on the electrically conductive layer, and a protective layer that protects the laminate, wherein the protective layer has a primary sealing layer that seals the solar cell, a secondary sealing layer that covers the laminate and the primary sealing layer, and a first sheet and a second sheet that sandwich the secondary sealing layer, and the secondary sealing layer and the second sheet are made of a material whose main component is silicone.

[0010] Silicone-based materials have a lower organic content than organic compounds. Therefore, silicone-based materials have a lower total heat generation rate upon combustion and higher flame retardancy than organic compounds. Silicone-based materials also have a higher thermal conductivity than organic compounds. Therefore, this embodiment makes it possible to realize a perovskite solar cell that can reduce the total heat generation rate and suppress a decrease in power generation efficiency. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a schematic diagram showing the configuration of a perovskite solar cell. [Figure 2] FIG. 1 is a schematic plan view of a perovskite solar cell. [Figure 3] 1 is an explanatory diagram of a method for manufacturing a perovskite solar cell. [Figure 4] 10 is a graph showing the results of a heat buildup test performed on the secondary sealing layer. [Figure 5] 10 is a graph showing the results of a heat buildup test conducted on a second sheet. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, embodiments of the perovskite solar cell according to the present disclosure will be described in detail with reference to the drawings. Note that the embodiments described below are examples for explaining the perovskite solar cell, and the perovskite solar cell is not limited to these embodiments. Therefore, the perovskite solar cell according to the present disclosure can be implemented in various forms without departing from the spirit of the present disclosure.

[0013] [Schematic configuration of perovskite solar cells] As shown in Figure 1, the perovskite solar cell 100 includes a laminate 10 and a protective layer 20. The laminate 10 is formed by laminating a substrate 1, a conductive layer 2, a solar cell 3, and a coating material S in this order.

[0014] 〔substrate〕 The substrate 1 functions as a support for the laminate 10. The substrate 1 is a transparent glass substrate, a semi-transparent glass substrate, a transparent resin substrate, or the like, and has insulating properties. As shown in Fig. 2, the substrate 1 has a rectangular shape when viewed along the Z direction.

[0015] As shown in Figures 1 and 2, a conductive conductive layer 2 is laminated on one surface of the substrate 1. The orientation of the perovskite solar cell 100 during use is not particularly limited, but it is preferable that the solar cell be used so that light is incident in the direction from the substrate 1 to the conductive layer 2. Hereinafter, the direction or side from the substrate 1 toward the conductive layer 2 will be referred to as the "Z1 direction" or "Z1 side," and the opposite direction or side will be referred to as the "Z2 direction" or "Z2 side." The Z1 direction and Z2 direction will be collectively referred to as the "Z direction." Furthermore, one of the directions perpendicular to the Z direction will be referred to as the "X direction," and the direction perpendicular to the Z direction and the X direction will be referred to as the "Y direction" (see Figure 2). Note that Figure 2 is a view of the perovskite solar cell 100 shown in Figure 1 as viewed in the Z2 direction (hereinafter also referred to as a plan view).

[0016] [Conductive Layer] The conductive layer 2 is formed on the Z1 side surface of the substrate 1 by CVD (chemical vapor deposition), sputtering, or the like. In this embodiment, the conductive layer 2 is formed on the entire Z1 side surface of the substrate 1. The conductive layer 2 contains, for example, fluorine-doped tin oxide (FTO), tin oxide (TO), or the like as a material. Solar cells 3 are arranged (stacked) on the Z1 side surface of the conductive layer 2.

[0017] [Solar cell] The solar cell 3 converts light energy into electrical energy. The solar cell 3 has an electron transport layer 31, a photoelectric conversion layer 32, a hole transport layer 33, and an electrode 34. In the solar cell 3, the electron transport layer 31, the photoelectric conversion layer 32, and the hole transport layer 33 are arranged in this order in the Z1 direction. In a plan view, the electron transport layer 31, the photoelectric conversion layer 32, and the hole transport layer 33 each have a rectangular shape, and in this embodiment, in a plan view, the electron transport layer 31, the photoelectric conversion layer 32, and the hole transport layer 33 each have the same size (area).

[0018] The electron transport layer 31 is disposed on the Z1-side surface of the conductive layer 2. The electron transport layer 31 receives electrons from the photoelectric conversion layer 32 (described later) and passes through (transports electrons). The electron transport layer 31 includes, as a material, a metal oxide such as titanium oxide, tin oxide, or zinc oxide. In this embodiment, the electron transport layer 31 includes an insulating layer 311 extending in the recess 21 formed by removing a portion of the conductive layer 2. The insulating layer 311 partitions the conductive layer 2 into two sections. In the example shown in FIGS. 1 and 2 , the insulating layer 311 extends along the Y direction, and thus the two partitioned conductive layers 2 are arranged parallel to each other along the X direction. In the electron transport layer 31, electrons can move in the Z direction but have difficulty moving in directions perpendicular to the Z direction (the X and Y directions), restricting movement between the two sections of the conductive layer 2.

[0019] Since the substrate 1, the conductive layer 2, and the electron transport layer 31 are optically transparent, light such as sunlight and indoor light is guided to the photoelectric conversion layer 32 without being substantially absorbed (or without being absorbed) by the substrate 1, the conductive layer 2, and the electron transport layer 31.

[0020] The photoelectric conversion layer 32 absorbs light energy and converts it into electrical energy. Specifically, the photoelectric conversion layer 32 absorbs light and transfers excited electrons and holes to perform photoelectric conversion. The photoelectric conversion layer 32 includes a perovskite layer made of a perovskite compound. The photoelectric conversion layer 32 also includes a porous oxide semiconductor layer (e.g., a porous titanium layer).

[0021] The hole transport layer 33 allows holes received from the photoelectric conversion layer 32 to pass through (transports holes). The hole transport layer 33 contains an organic compound such as chlorobenzene as a material. An electrode 34 is disposed on the Z1 side surface of the hole transport layer 33.

[0022] The electrode 34 is conductive and can form an electrical path as a positive electrode with the conductive layer 2, which is a negative electrode, via the bus bar B.

[0023] 2, in a plan view, a pair of bus bars B are each arranged (stacked) on the Z1-side surface of the conductive layer 2, which is outer than the solar cell 3 in the X direction. Specifically, each of the pair of bus bars B is arranged on a partial region of the Z1-side surface of the conductive layer 2, spaced apart from the solar cell 3. The bus bars B contain, as materials, elemental metals such as gold, platinum, silver, copper, etc., alloys of these metals, oxide conductors such as FTO and ITO, etc.

[0024] 1, the electrode 34 is disposed so as to be electrically connected to the Z1-side surface of the conductive layer 2 in the Z2 direction from the Z1-side surface of the hole transport layer 33 via the side surfaces of the hole transport layer 33, the photoelectric conversion layer 32, and the electron transport layer 31 (see also FIG. 3). The electrode 34 contains, for example, carbon nanotubes as a material.

[0025] In the perovskite solar cell 100, light such as sunlight is incident from the substrate 1 in the Z1 direction. When the light reaches the photoelectric conversion layer 32 via the substrate 1, the conductive layer 2, and the electron transport layer 31, it is absorbed in the photoelectric conversion layer 32, resulting in the generation of electrons and holes. The electrons generated in the photoelectric conversion layer 32 migrate to the conductive layer 2 (negative electrode) via the electron transport layer 31. At the same time, the holes generated in the photoelectric conversion layer 32 migrate to the electrode 34 (positive electrode) electrically connected to the hole transport layer 33. When a load (not shown) is electrically connected between the conductive layer 2 (negative electrode) and the electrode 34, the holes combine with the electrons that have passed through the load. As a result, electricity is generated. Note that the electrons moving through the electron transport layer 31 move smoothly along the Z2 direction to reach the conductive layer 2, but as described above, the insulating layer 311 restricts their movement in a direction perpendicular to the Z direction. In other words, the perovskite solar cell 100 is configured to prevent short-circuiting.

[0026] [Coating material] The coating material S has insulating properties and is disposed on the Z1 side of the solar cell 3 and the conductive layer 2 so as to cover the solar cell 3. That is, the coating material S is in contact with the Z1 side surface, the X direction surface, and the Y direction surface of the electrode 34 of the solar cell 3. A portion of the coating material S is also disposed on a portion of the Z1 direction surface of the conductive layer 2. The coating material S may be a film-like (sheet-like) member.

[0027] The coating material S has a plurality of communication holes (air holes) formed therein that connect the inside and outside of the coating material S. The coating material S is, for example, a porous film, a mesh sheet, an embossed sheet, or the like, and contains resin (PPS: polyphenylene sulfide resin), glass, or the like as materials. The coating material S may have a melting point (e.g., 120°C or higher) higher than the temperature (e.g., 80°C) when bonding the primary sealing layer 4 and the conductive layer 2, which will be described later. The coating material S may or may not be provided at a position spaced apart from the solar cell 3.

[0028] [Protective layer] [Primary sealing layer] The protective layer 20 includes a primary sealing layer 4, a stress relief layer 5, a secondary sealing layer 6, a first sheet 7, and a second sheet 8. The first sheet 7 is generally referred to as a protective sheet, and the second sheet 8 is generally referred to as a back sheet. As shown in FIG. 1 , the primary sealing layer 4 is composed of an adhesive 41 and an aluminum-deposited PET film made of an aluminum foil 42 and a PET film 43. The adhesive 41 may contain a getter material that adsorbs moisture and gas, such as an olefin-based adhesive, an epoxy-based adhesive, or an acrylic-based adhesive. The adhesive 41 may also have waterproof or gas-barrier properties. The adhesive 41 is disposed on the upper side (Z1 side) of the solar cell 3 and the conductive layer 2 so as to cover the solar cell 3. That is, the adhesive 41 is bonded to the Z1-side surface of the coating material S, the X-direction surface of the coating material S, and the Y-direction surface of the coating material S. A portion of the adhesive 41 is also bonded to a portion of the Z1-side surface of the conductive layer 2.

[0029] An aluminum foil 42 and a PET film 43 are arranged in this order on the Z1 side surface of the adhesive 41. The aluminum foil 42 is preferably conductive and contains, as its material, a metal oxide such as aluminum oxide or silicon oxide, or a metal such as aluminum. The PET film 43 contains, as its material, a resin such as polyethylene terephthalate. The adhesive 41 and the aluminum foil 42 are bonded together, and the aluminum foil 42 and the PET film 43 are bonded together, respectively, to form the primary sealing layer 4. In a plan view of the perovskite solar cell 100, the areas of the adhesive 41, the aluminum foil 42, and the PET film 43 are equal. Furthermore, the area of ​​the primary sealing layer 4 in a plan view is smaller than the area of ​​the conductive layer 2.

[0030] [Stress relaxation layer] In this embodiment, the stress relief layer 5 is disposed on the Z1-side surface of the PET film 43 of the primary sealing layer 4, as shown in FIG. 1 . The area of ​​the stress relief layer 5 in a plan view is preferably approximately the same as the area of ​​the PET film 43. The stress relief layer 5 may be disposed so as to cover the X-direction and Y-direction surfaces of the aluminum foil 42 and the adhesive 41 of the primary sealing layer 4. In this case, the stress relief layer 5 is preferably disposed around the primary sealing layer 4. The stress relief layer 5 is, for example, a resin film such as polyimide or polyethylene terephthalate. The stress relief layer 5 is disposed on the surface of the PET film 43 of the primary sealing layer 4 without being bonded to the PET film 43. In other words, no adhesive or the like is disposed between the PET film 43 and the stress relief layer 5. On the other hand, the stress relief layer 5 and the secondary sealing layer 6 are bonded to each other by the secondary sealing layer 6.

[0031] Because the Z1-side surface of stress relaxation layer 5 is bonded to secondary sealing layer 6, when secondary sealing layer 6 is deformed by an external force, stress accompanying the deformation of secondary sealing layer 6 acts on the Z1-direction surface of stress relaxation layer 5. The stress acting on stress relaxation layer 5 causes it to contract or expand and deform. On the other hand, because the Z2-side surface of stress relaxation layer 5 is not bonded to PET film 43 of primary sealing layer 4, no stress acts on PET film 43 even if stress relaxation layer 5 is deformed. For this reason, primary sealing layer 4 is less susceptible to the deformation of secondary sealing layer 6, and deterioration of perovskite solar cell 100 due to external forces is suppressed.

[0032] The dimension of the stress relaxation layer 5 in the Z direction is preferably, for example, 100 μm or less. In other words, the stress relaxation layer 5 is preferably in the form of a thin film. This prevents the dimension of the perovskite solar cell 100 in the Z direction from increasing.

[0033] [Secondary sealing layer] The laminate 10 and the primary sealing layer 4 are sealed by the secondary sealing layer 6, the first sheet 7, and the second sheet 8. The first sheet 7 and the second sheet 8 are adhered to the secondary sealing layer 6 and serve to prevent adhesion between an external member and the secondary sealing layer 6. The first sheet 7 is disposed on the Z2 side of the laminate 10, and the second sheet 8 is disposed on the Z1 side.

[0034] Secondary sealing layer 6 is disposed so as to cover stack 10. Therefore, as shown in Figure 1, the area of ​​secondary sealing layer 6 in plan view is larger than the areas of primary sealing layer 4 and stack 10. Secondary sealing layer 6 adheres closely to stack 10 and primary sealing layer 4, and protects perovskite solar cell 100 from external forces acting on them.

[0035] Secondary sealing layer 6 is made of a material whose main component is silicone (hereinafter simply referred to as the "first silicone-containing material"). The first silicone-containing material contains 40% to 80% by weight of silicone and 20% to 60% by weight of inorganic filler. The dimension of secondary sealing layer 6 in the Z direction is preferably, for example, 125 μm to 250 μm.

[0036] The first silicone-containing material has a lower organic content than conventionally used organic compounds such as ethylene vinyl acetate (EVA) and polyolefin elastomer (POE). Therefore, the first silicone-containing material has higher flame retardancy than conventional organic compounds. Consequently, using the first silicone-containing material for the secondary encapsulation layer 6 can reduce the amount of heat generated by the perovskite solar cell 100 during combustion.

[0037] Furthermore, the first silicone-containing material has a higher thermal conductivity than conventional organic compounds. Therefore, when the first silicone-containing material is used in the secondary encapsulation layer 6, the heat generated by the power generation of the solar cells 3 can be rapidly conducted and released to the outside of the perovskite solar cell 100. This makes it possible to suppress the temperature rise of the perovskite solar cell 100 during power generation and to suppress a decrease in power generation efficiency.

[0038] [First sheet] The first sheet 7 is made of, for example, a fluorine-based resin. Since light enters the first sheet 7 from the Z2 direction, it is preferable that the first sheet 7 is transparent.

[0039] [Second seat] Similarly to the secondary sealing layer 6, the second sheet 8 is made of a material primarily composed of silicone. Silicone-based materials have a lower organic content than conventionally used organic compounds such as polyethylene terephthalate (PET). Therefore, silicone-based materials have higher flame retardancy than conventional organic compounds. As a result, using a silicone-based material for the second sheet 8 can reduce the amount of heat generated by the perovskite solar cell 100 during combustion.

[0040] Furthermore, materials containing silicone as a main component have higher thermal conductivity than conventional organic compounds. Therefore, when a material containing silicone as a main component is used for the second sheet 8, the heat generated by power generation in the solar cell 3 can be quickly conducted and released to the outside of the perovskite solar cell 100. This makes it possible to suppress temperature increases in the perovskite solar cell 100 during power generation and to suppress decreases in power generation efficiency.

[0041] The second sheet 8 uses a material containing silicone as its main component, similar to the secondary sealing layer 6, but is not exactly the same material as the secondary sealing layer 6. The second sheet 8 contains glass cloth and inorganic filler, which are not contained in the secondary sealing layer 6. Specifically, the glass cloth is impregnated with silicone containing inorganic filler. Hereinafter, the silicone-containing material used for the second sheet 8 will also be referred to as the "second silicone-containing material." The second silicone-containing material contains 5% by weight to 40% by weight, 2% by weight to 10% by weight, and 60% by weight to 95% by weight of inorganic filler. The dimension of the second sheet 8 in the Z direction may be, for example, 150 μm.

[0042] Since glass cloth is an inorganic material, when the second sheet 8 contains glass cloth, the organic material content in the second sheet 8 is further reduced, and the total heat generated during combustion can be further reduced.

[0043] Because inorganic fillers are also inorganic, the inclusion of inorganic filler in second sheet 8 further reduces the organic content in second sheet 8, further reducing the amount of heat generated during combustion. Furthermore, because inorganic fillers have high thermal conductivity, the inclusion of inorganic filler in second sheet 8 further increases the thermal conductivity of second sheet 8, allowing heat generated by power generation in solar cell 3 to be more quickly conducted and released to the outside of perovskite solar cell 100. Specifically, while polyethylene terephthalate (PET) used in the second sheet of conventional perovskite solar cells had a thermal conductivity of 0.2 W / mK, the second silicone-containing material used in second sheet 8 of perovskite solar cell 100 of the present embodiment had a thermal conductivity of 2.0 W / mK, which is 10 times higher. Thus, by using the second silicone-containing material as the material for second sheet 8, it is possible to suppress the temperature rise of perovskite solar cell 100 during power generation and further suppress a decrease in power generation efficiency.

[0044] [Method for manufacturing perovskite solar cells] Next, a manufacturing method of the perovskite solar cell 100 will be described with reference to FIG. 3. First, a laminate 10 is formed in a laminate formation process (#1). In the laminate formation process, a conductive layer 2 is formed on the Z1 side surface of the substrate 1. The conductive layer 2 may be formed by, for example, CVD (chemical vapor deposition) or sputtering. Next, laser scribing is performed to partially remove the conductive layer 2, forming recesses 21. Thereafter, solar cells 3 are formed on the Z1 side surface of the conductive layer 2 by a known method. A coating material S may be disposed on the surface of the solar cells 3 using an adhesive or the like. The bus bars B may be disposed in the laminate formation process.

[0045] Next, a primary sealing layer 4 is formed in a primary sealing layer formation step (#2). The primary sealing layer 4 is formed by thermally curing or UV-curing the adhesive 41 placed on the surface of the solar cell 3, and then adhering an aluminum foil 42 and a PET film 43 to the Z1-direction surface of the adhesive 41 with an adhesive or the like. In this way, the solar cell 3 is sealed by the primary sealing layer 4.

[0046] Next, the stress relaxation layer 5 is formed in a stress relaxation layer forming process (#3). In the stress relaxation layer forming process, the stress relaxation layer 5 is disposed in a non-adhered state on the Z1 direction surface of the PET film 43 of the primary sealing layer 4. Since the stress relaxation layer 5 in this embodiment is a resin film, it is preferable to dispose the resin film on the Z1 direction surface of the PET film 43.

[0047] Finally, the secondary sealing layer 6, the first sheet 7, and the second sheet 8 are formed in the secondary sealing layer formation step (#4). In the secondary sealing layer formation step, the laminate 10 and the primary sealing layer 4 are covered with the first sealing material 6a and the second sealing material 6b to form the secondary sealing layer 6. That is, the secondary sealing layer 6 is composed of the first sealing material 6a and the second sealing material 6b. The first sealing material 6a and the second sealing material 6b may be formed in advance, with the first sheet 7 adhered to the Z2-direction surface of the first sealing material 6a and the second sheet 8 adhered to the Z1-direction surface of the second sealing material 6b. Note that the first sealing material 6a and the second sealing material 6b do not have to be formed in advance. For example, the secondary sealing layer 6 may be formed by disposing a sheet-like silicone-containing material so as to cover the laminate 10, the primary sealing layer 4, and the stress relief layer 5 and then curing the material.

[0048] 3, the substrate 1 and the conductive layer 2 are fitted into the first recess 6a1 of the first sealing material 6a, and the laminate 10 having the primary sealing layer 4 and the stress relaxation layer 5 formed thereon is fitted into the second recess 6b1 of the second sealing material 6b, whereby the laminate 10, the primary sealing layer 4, and the stress relaxation layer 5 are covered with the secondary sealing layer 6. Then, by thermally welding the first sealing material 6a and the second sealing material 6b while they are in contact with each other, the secondary sealing layer 6 adheres to the laminate 10, the primary sealing layer 4, and the stress relaxation layer 5, and they are sealed.

[0049] In the perovskite solar cell 100 formed in this manner, the secondary encapsulation layer 6 is formed from a first silicone-containing material, and the second sheet 8 is formed from a second silicone-containing material. Therefore, compared to conventional perovskite solar cells that use organic compounds for the secondary encapsulation layer and second sheet, the amount of heat generated during combustion is small and the thermal conductivity is high. As a result, solar panels using the perovskite solar cell 100 of this embodiment can be certified as equivalent to non-combustible materials.

[0050] [Pyrogenicity test] The total heat release of the materials used in the perovskite solar cell 100 according to this embodiment was measured. The measurement was carried out in accordance with ISO 5660-1:2002 "Fire reaction test - Heat release rate, smoke production rate, mass loss rate - Part 1: Heat release rate (cone calorimeter method), smoke production rate (dynamic measurement)." Hereinafter, this test will also be referred to as the "heat release test."

[0051] In the heat generation test, the first silicone-containing material used in the secondary encapsulation layer 6 of the perovskite solar cell 100 of this embodiment and the second silicone-containing material used in the second sheet 8 were used as examples. As a comparative example for the first silicone-containing material, polyolefin elastomer (POE) used in the secondary encapsulation layer of conventional perovskite solar cells was used. As a comparative example for the second silicone-containing material, polyethylene terephthalate (PET) used in the second sheet of conventional perovskite solar cells was used. In both cases, tests were conducted on each material alone using 10 cm square test pieces of the same thickness. In order to be recognized as a non-combustible material in the heat generation test, the total heat generation must always be 8 MJ / m during a heating time of 20 minutes (1200 seconds). 2 The following is required:

[0052] Figure 4 shows a graph of the results of heat generation tests conducted on the secondary encapsulation layer. As shown in Figure 4, the POE used in the secondary encapsulation layer of conventional perovskite solar cells generated a maximum total heat generation of 9.4 MJ / m. 2 In contrast, the first silicone-containing material used in the secondary encapsulation layer 6 of the perovskite solar cell 100 of this embodiment had a total heat output of up to 4.5 MJ / m 2 Therefore, the first silicone-containing material had a heat release amount that qualified it as a non-combustible material in the heat release test.

[0053] Figure 5 shows a graph of the results of the heat generation test conducted on the second sheet. As shown in Figure 5, the PET used as the second sheet in conventional perovskite solar cells generated a maximum total heat generation of 4.0 MJ / m 2 In contrast, the second silicone-containing material used in the second sheet 8 of the perovskite solar cell 100 of this embodiment had a maximum total heat output of 1.1 MJ / m 2 Therefore, the second silicone-containing material had a heat release amount that qualified it as a non-combustible material in the heat release test.

[0054] In conventional perovskite solar cells, the total heat generated by the secondary encapsulation layer using POE and the second sheet using PET is 8MJ / m2 . Therefore, solar panels using conventional perovskite solar cells are not recognized as equivalent to non-combustible materials. In contrast, in the perovskite solar cell 100 of this embodiment, the adhesive 41 of the primary sealing layer 4 is made of organic materials, but the other components, such as the substrate 1, conductive layer 2, and solar cell 3, are mainly made of inorganic materials. The sum of the total heat values ​​of the secondary sealing layer 6 and second sheet 8, which use a silicone-containing material, is 5.6 MJ / m 2 and 8MJ / m 2 Therefore, even when the presence of organic matter constituting the adhesive 41 and the like is taken into consideration, the total calorific value at the time of combustion of the perovskite solar cell 100 is 8 MJ / m 2 Therefore, if the perovskite solar cell 100 of this embodiment is used, the solar panel is more likely to be recognized as equivalent to a non-combustible material.

[0055] Other Embodiments In the above embodiment, the secondary sealing layer 6 and the second sheet 8 are made of a material mainly composed of silicone, but this is not limiting. Furthermore, at least one of the adhesive 41 of the primary sealing layer 4 and the first sheet 7 may also be made of a material mainly composed of silicone.

[0056] [Summary of the above embodiment] Hereinafter, the perovskite solar cell (100) described in the above embodiment will be considered to have the following configuration.

[0057] <1> One embodiment of a perovskite solar cell (100) comprises a laminate (10) having an electrically conductive conductive layer (2) disposed on a substrate (1) and solar cells (3) disposed on the conductive layer (2), and a protective layer (20) that protects the laminate (10). The protective layer (20) has a primary sealing layer (4) that seals the solar cells (3), a secondary sealing layer (6) that covers the laminate (10) and the primary sealing layer (4), and a first sheet (7) and a second sheet (8) that sandwich the secondary sealing layer (6). The secondary sealing layer (6) and the second sheet (8) are made of a material whose main component is silicone.

[0058] Silicone-based materials have a lower organic content than organic compounds. Therefore, silicone-based materials have a lower total heat generation rate upon combustion and are more flame-retardant than organic compounds. Silicone-based materials also have a higher thermal conductivity than organic compounds. Therefore, this embodiment can realize a perovskite solar cell (100) that can reduce the total heat generation rate and suppress a decrease in power generation efficiency.

[0059] <2> the above <1> In the perovskite solar cell (100) described above, the second sheet (8) preferably contains glass cloth.

[0060] According to this embodiment, since glass cloth is an inorganic material, by containing glass cloth in the second sheet (8), the content of organic matter in the second sheet (8) can be reduced, and the total amount of heat generated during combustion can be further reduced.

[0061] <3> the above <2> In the perovskite solar cell (100) described above, it is preferable that the second sheet (8) further contains an inorganic filler.

[0062] According to this embodiment, since the inorganic filler is also an inorganic material, the second sheet (8) contains an inorganic filler, which further reduces the organic material content in the second sheet (8) and further reduces the amount of heat generated during combustion. Furthermore, since inorganic fillers have high thermal conductivity, the second sheet (8) contains an inorganic filler, which further increases the thermal conductivity of the second sheet (8), allowing the heat generated by power generation in the solar cell (3) to be conducted more quickly and released to the outside of the perovskite solar cell (100).

[0063] <4> the above <3> In the perovskite solar cell (100) described above, the second sheet (8) preferably contains 5% by weight or more and 40% by weight or less of silicone, 2% by weight or more and 10% by weight or less of glass cloth, and 60% by weight or more and 95% by weight or less of inorganic filler.

[0064] According to this embodiment, in the perovskite solar cell 100, the second sheet 8 contains 5% by weight to 40% by weight of silicone, 2% by weight to 10% by weight of glass cloth, and 60% by weight to 95% by weight of inorganic filler. Therefore, the second sheet 8 can reduce the total heat generation amount and suppress a decrease in power generation efficiency compared to when an organic compound is used. [Industrial Applicability]

[0065] The present disclosure is applicable to perovskite solar cells. [Explanation of symbols]

[0066] 1: substrate, 2: conductive layer, 3: solar cell, 4: primary sealing layer, 6: secondary sealing layer, 7: first sheet, 8: second sheet, 10: laminate, 20: protective layer, 100: perovskite solar cell

Claims

1. a laminate including a conductive layer disposed on a substrate and a solar cell disposed on the conductive layer; a protective layer for protecting the laminate, the protective layer includes a primary sealing layer that seals the solar cell, a secondary sealing layer that covers the laminate and the primary sealing layer, and a first sheet and a second sheet that sandwich the secondary sealing layer; A perovskite solar cell, wherein the secondary encapsulation layer and the second sheet are made of a material containing silicone as a main component.

2. The perovskite solar cell according to claim 1 , wherein the second sheet contains glass cloth.

3. The perovskite solar cell according to claim 2 , wherein the second sheet further contains an inorganic filler.

4. 4. The perovskite solar cell according to claim 3, wherein the second sheet contains 5% by weight or more and 40% by weight or less of the silicone, 2% by weight or more and 10% by weight or less of the glass cloth, and 60% by weight or more and 95% by weight or less of the inorganic filler.

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