Solar cell module

Abstract

A solar cell module (100) comprises: a conductive layer (2) disposed on a substrate (1); a perovskite solar cell element (3) disposed on the conductive layer (2); an electrode (4) disposed on the perovskite solar cell element (3); and a sealing material layer (5) for sealing the perovskite solar cell element (3) and the electrode (4). The sealing material layer (5) has at least one hydrophilic base layer (51), at least one intermediate layer (52) having hydrophilicity and peelability and comprising a non-silicon-based material, and at least one glass layer (53). The intermediate layer (52) is disposed between the base layer (51) and the glass layer (53).

Description

solar cell module

[0001] The present disclosure relates to solar cell modules.

[0002] Solar cell modules having perovskite solar cell elements that convert solar light energy into electrical energy have attracted attention because of their high energy conversion efficiency and light weight compared to other solar cell modules. However, perovskite solar cell elements have the problem of being easily deteriorated by oxygen, water, etc., and various techniques have been proposed to address this problem (see, for example, Patent Documents 1 and 2).

[0003] Patent Document 1 describes that the solar cells in a solar cell module are sealed with multiple surface coating materials, of which a fluororesin film layer is formed on the outermost surface, and a glass layer (called a transparent thin film layer in Patent Document 1) obtained by coating polysilazane is formed on the perovskite solar cell element side of the fluororesin film layer.

[0004] Patent Document 2 describes a solar cell module in which a sealing material layer such as an EVA film and a resin film are laminated in this order on a solar cell, and the resin film is then glass-coated.

[0005] Japanese Patent Laid-Open No. 9-199740 Japanese Patent Laid-Open No. 2012-64767

[0006] Glass has high water-blocking and gas-barrier properties, so covering perovskite solar cell elements with a glass layer can improve the durability of the solar cell module. The glass layer is formed by applying and curing a polysilazane or the like dissolved in a solvent. However, forming the glass layer directly on the solar cell may result in a reaction between the solvent and the solar cell. For this reason, as in Patent Documents 1 and 2, a base layer such as a resin film must be provided between the solar cell and the glass layer. However, because the base layer made of a resin or the like and the glass layer have different linear expansion coefficients, when the solar cell module is subjected to a thermal cycle, the glass layer bonded to the base layer cannot follow the deformation of the base layer due to the thermal cycle, resulting in the occurrence of cracks in the glass layer.

[0007] Furthermore, in order to provide a glass layer on a base layer such as a resin film, the intermediate layer must be hydrophilized, which increases the number of steps involved in manufacturing the solar cell module and increases manufacturing costs.

[0008] The present disclosure has been made in view of the above-mentioned problems, and has an object to provide a solar cell module that is highly durable and highly efficient to produce.

[0009] A solar cell module according to the present disclosure has a characteristic configuration comprising an electrically conductive layer disposed on a substrate, perovskite solar cell elements disposed on the conductive layer, electrodes disposed on the perovskite solar cell elements, and an encapsulant layer that encapsulates the perovskite solar cell elements and the electrodes, wherein the encapsulant layer has at least one hydrophilic base layer, one intermediate layer that is hydrophilic and peelable and made of a non-silicon-based material, and one glass layer, and the intermediate layer is disposed between the base layer and the glass layer.

[0010] According to this configuration, the perovskite solar cell element and electrodes are sealed by a sealing material layer having a glass layer, which isolates them from the atmosphere and improves the durability of the solar cell module. Furthermore, a peelable intermediate layer is disposed between the base layer and the glass layer, so the glass layer is not bonded to the base layer or the intermediate layer. Therefore, even if the solar cell module is subjected to a thermal cycle, the base layer and the intermediate layer can deform independently of the glass layer, and stresses associated with deformation of the base layer and the intermediate layer do not act on the glass layer, thereby suppressing cracking of the glass layer. In other words, the intermediate layer acts as a stress relaxation layer, resulting in a solar cell module with a highly durable glass layer.

[0011] Furthermore, because the intermediate layer is hydrophilic, it can be easily formed on a hydrophilic base layer, eliminating the need for a hydrophilic treatment to form a glass layer on the base layer. This simplifies the manufacturing process of the solar cell module, improving productivity and reducing production costs. Furthermore, because the intermediate layer is made of a non-silicon material, it can suppress the diffusion and migration of Si, thereby preventing performance degradation of the solar cell module over long-term use.

[0012] FIG. 1 is a schematic diagram showing the configuration of a solar cell module according to a first embodiment; FIG. 2 is a schematic plan view of a solar cell module according to a first embodiment; FIG. 3 is a schematic plan view of a solar cell module according to a second embodiment; FIG. 4 is a schematic plan view of a solar cell module according to a second embodiment; FIG. 5 is a schematic diagram showing the configuration of a solar cell module according to another embodiment; FIG. 6 is a schematic diagram showing the configuration of a solar cell module according to another embodiment.

[0013] [First embodiment] Hereinafter, an embodiment of a solar cell module according to the present disclosure will be described with reference to the drawings. However, the present disclosure is not limited to the following embodiment, and various modifications are possible without departing from the spirit of the present disclosure.

[0014] 1 , the solar cell module 100 includes a solar cell 10, a sealing material layer 5, and a sealing portion 6. The solar cell 10 is formed by laminating a substrate 1, a conductive layer 2, a perovskite solar cell element 3, and an electrode 4 in this order. The solar cell module 100 may include a plurality of solar cells 10.

[0015] [Substrate] The substrate 1 functions as a support for the perovskite solar cell element 3 and the electrode 4. 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 Figure 2, the substrate 1 has a rectangular shape when viewed along the Z direction.

[0016] As shown in FIG. 1 , a conductive conductive layer 2 is laminated on a first surface 11 of a substrate 1. The orientation of the solar cell module 100 during use is not particularly limited, but it is preferable to use it so that light is incident on the Z2 side of the substrate 1. Hereinafter, the direction from the substrate 1 to the conductive layer 2 will be referred to as the "Z1 direction" (an example of a lamination direction), the opposite direction will be referred to as the "Z2 direction," and the Z1 direction and the 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 FIG. 2 ). Note that FIG. 2 is a view of the solar cell module 100 shown in FIG. 1 as viewed along the Z2 direction.

[0017] [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. The perovskite solar cell element 3 is disposed (stacked) on the conductive layer 2 (on the Z1-side surface).

[0018] [Perovskite solar cell element] The perovskite solar cell element 3 converts light energy into electrical energy. The perovskite solar cell element 3 has an electron transport layer 31, a photoelectric conversion layer 32, and a hole transport layer 33, which are arranged in this order along the Z1 direction. When viewed along the Z direction, 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, when viewed along the Z direction, the electron transport layer 31, the photoelectric conversion layer 32, and the hole transport layer 33 each have the same size (area).

[0019] The electron transport layer 31 is disposed on the Z1-side surface of the conductive layer 2. The electron transport layer 31 passes through (transports electrons) the electrons received from the photoelectric conversion layer 32 (described later). 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 into the recess 21 formed by removing a portion of the conductive layer 2. The insulating layer 311 divides the conductive layer 2, which is in contact with the perovskite solar cell element 3, into two sections in 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 their movement between the two sections of the conductive layer 2 corresponding to each perovskite solar cell element 3. The electron transport layer 31 is sometimes referred to as a "blocking layer."

[0020] 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.

[0021] 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).

[0022] The hole transport layer 33 transmits holes received from the photoelectric conversion layer 32 (transports holes). The hole transport layer 33 contains an organic compound such as chlorobenzene as a material. The electrode 4 is disposed on the hole transport layer 33 (on the Z1 side).

[0023] The electrode 4 is conductive and functions as a positive electrode. As shown in FIG. 1 , the electrode 4 is disposed on (a partial region of) the Z1-side surface of the conductive layer 2, extending in the Z direction from the Z1-side surface of the hole transport layer 33, passing through each side surface of the perovskite solar cell element 3. The electrode 4 contains, for example, graphite, carbon black, carbon nanotubes, carbon nanofibers, carbon fibers, graphene, fullerene, or the like as a material. The electrode 4 may also be formed using a metal such as gold, platinum, silver, or copper, an alloy thereof, or an oxide conductor such as FTO or indium tin oxide (ITO).

[0024] A laminate constituted by the perovskite solar cell element 3 and the electrode 4 laminated on the conductive layer 2 of the substrate 1 in the above-described manner is referred to as a solar cell 10. A solar cell module 100 may be formed by electrically connecting a plurality of solar cell cells 10.

[0025] Light, such as sunlight, enters the solar cell module 100 through the second surface 12 of the substrate 1. The light travels through the substrate 1, the conductive layer 2, and the electron transport layer 31 to the photoelectric conversion layer 32, where it is absorbed, generating 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 4 (positive electrode), which is electrically connected to the hole transport layer 33. When a load (not shown) is connected between the conductive layer 2 and the electrode 4, the holes combine with the electrons that have traveled through the load. This results in the generation of electricity. Note that electrons traveling 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 solar cell module 100 is configured to prevent short circuits.

[0026] 1 and 2 , the perovskite solar cell element 3 and the electrode 4 are sealed by a sealing material layer 5 and a sealing portion 6. This blocks the perovskite solar cell element 3 and the electrode 4 from the atmosphere, improving the durability of the solar cell module 100.

[0027] The encapsulant layer 5 has a hydrophilic base layer 51 arranged on the Z1-side surface of the electrode 4, an intermediate layer 52 arranged on the Z1-side surface of the base layer 51, and a glass layer 53 arranged on the Z1-side surface of the intermediate layer 52. As shown in Figure 2, when viewed along the Z direction, the base layer 51, the intermediate layer 52, and the glass layer 53 are each rectangular and have the same size (area). Furthermore, the area of ​​the encapsulant layer 5 in a plan view (viewed in the Z direction) is larger than the areas of the perovskite solar cell element 3 and the electrode 4.

[0028] The hydrophilic base layer 51 may be a transparent resin or the like that is solvent-resistant and heat-resistant, and for example, polyethylene terephthalate (PET) or the like can be used. When forming the glass layer 53, a solution in which a glass component is dissolved in a solvent such as ether is coated toward the Z1 side of the solar cell 10, and the solvent resistance of the base layer 51 makes it possible to protect the perovskite solar cell element 3 and the electrode 4 from the solvent. Furthermore, the heat resistance allows the solar cell module 100 to maintain its durability even when subjected to a thermal cycle.

[0029] The intermediate layer 52 is hydrophilic and release-resistant, and is made of a non-silicone material. For example, a cross-linked alkyl compound can be used as the intermediate layer 52. The intermediate layer 52 is disposed between the base layer 51 and the glass layer 53. In this embodiment, since both the base layer 51 and the intermediate layer 52 are hydrophilic, it is easy to form the intermediate layer 52 on the surface of the base layer 51. The intermediate layer 52 may also be obtained by coating the surface of the base layer 51 with a non-silicone resin.

[0030] When forming glass layer 53 on the surface of resin or the like, a hydrophilic treatment of the resin or the like is required, but since intermediate layer 52 is hydrophilic, no hydrophilic treatment is required, and glass layer 53 can be easily formed on the surface of intermediate layer 52. Therefore, the hydrophilic treatment step can be eliminated in the manufacturing process of solar cell module 100, thereby improving productivity and reducing production costs.

[0031] Furthermore, because the intermediate layer 52 has peelability, even if a glass layer 53 is formed on the Z1-side surface of the intermediate layer 52, the intermediate layer 52 and the glass layer 53 are not bonded to each other. Because the base layer 51, the intermediate layer 52, and the glass layer 53 have different linear expansion coefficients, if the intermediate layer 52 and the glass layer 53 were bonded to each other, the glass layer 53 would not be able to follow the expansion and contraction of the base layer 51 and the intermediate layer 52 due to thermal cycling, which could result in cracking of the glass layer 53. However, in this embodiment, because the intermediate layer 52 and the glass layer 53 are not bonded to each other, stresses associated with the expansion and contraction of the base layer 51 and the intermediate layer 52 do not act on the glass layer 53, preventing cracking of the glass layer 53. In other words, the intermediate layer 52 acts as a stress relief layer, thereby improving the durability of the glass layer 53.

[0032] Furthermore, if the intermediate layer 52 contains Si, the Si is likely to diffuse into the base layer 51 and the glass layer 53, and the composition and function of these layers may be impaired when the solar cell module 100 is subjected to a thermal cycle. In this embodiment, the intermediate layer 52 is made of a non-silicon material, so there is no need to worry about the diffusion and migration of Si, and the durability of the solar cell module 100 can be improved.

[0033] The glass layer 53 may be made of polysilazane or the like. If the glass layer 53 is formed on the Z1 side surface of the intermediate layer 52, the glass layer 53 can be formed to have a uniform thickness regardless of the shape of the electrode 4, and therefore cracks in the glass layer 53 due to variations in thickness can be suppressed.

[0034] 1 and 2 , the outer edge of the sealing material layer 5 is covered by a sealing portion 6, and the sealing portion 6 that protrudes outward from the outer edge of the sealing material layer 5 is adhered to the sealing material layer 5 and the conductive layer 2, thereby sealing the perovskite solar cell element 3 and the electrode 4. The sealing portion 6 prevents water and oxygen from penetrating into the sealing material layer 5 from the outer edge. The sealing portion 6 can be made of, for example, an epoxy resin. In this embodiment, since the sealing material layer 5 has insulating properties, the sealing portion 6 may also have conductivity.

[0035] [Method for manufacturing solar cell module] Next, a description will be given of a method for manufacturing the solar cell module 100. The method for manufacturing the solar cell module 100 in this embodiment includes a first step of forming the solar cell 10 and a second step of arranging the encapsulant layer 5 on the solar cell 10.

[0036] First, a first step is carried out to form a solar cell 10. In the first step, a conductive layer 2 is formed on a first surface 11 of a substrate 1. The conductive layer 2 may be formed by, for example, CVD (chemical vapor deposition) or sputtering. Next, a laser scribe is carried out to partially remove the conductive layer 2, forming a recess 21. Thereafter, a perovskite solar cell element 3 and an electrode 4 are formed on the Z1 side surface of the conductive layer 2 by a known method, thereby obtaining a solar cell 10.

[0037] Next, a second step is performed to place the encapsulant layer 5 on the solar cell 10. In the second step, first, the base layer 51 on which the intermediate layer 52 is formed is placed on the electrode 4 so that the surface on which the intermediate layer 52 is formed faces the Z1 side. As a result, the perovskite solar cell element 3 and the electrode 4 are covered with the base layer 51 and the intermediate layer 52.

[0038] Next, a glass layer 53 is formed on the Z1 side surface of the intermediate layer 52. The glass layer 53 is obtained by applying a solution of polysilazane dissolved in ether onto the intermediate layer 52 and then curing the solution. Thereafter, a sealing portion 6 is applied to the outer edge of the sealing material layer 5 and cured. This seals the perovskite solar cell element 3 and the electrode 4, and a durable solar cell module 100 can be obtained.

[0039] Second Embodiment Next, a solar cell module 100 according to a second embodiment will be described with reference to Figures 3 and 4. As shown in Figure 3, at the outer edge of the sealing material layer 5, the glass layer 53 extends outward beyond the outer edges of the base layer 51 and the intermediate layer 52. As shown in Figure 4, the area of ​​the glass layer 53 according to the second embodiment in a plan view (viewed in the Z direction) is larger than the area of ​​the base layer 51 and the intermediate layer 52. Therefore, the base layer 51 and the intermediate layer 52 are covered with the glass layer 53, and the glass layer 53 extending outward beyond the outer edges of the base layer 51 and the intermediate layer 52 is adhered to the conductive layer 2, thereby sealing the perovskite solar cell element 3 and the electrode 4.

[0040] In this embodiment, the glass layer 53 extending outward beyond the outer edges of the base layer 51 and the intermediate layer 52 bonds the sealant layer 5 and the conductive layer 2, eliminating the need for the sealing portion 6. Therefore, in the second step of disposing the sealant layer 5 on the solar cell 10, the step of providing the sealing portion 6 can be omitted, thereby improving productivity and reducing production costs.

[0041] The thickness (dimension in the Z direction) of the glass layer 53 extending outward from the outer edges of the base layer 51 and the intermediate layer 52 is preferably 1 μm or less. If the thickness of the glass layer 53 is 1 μm or less, cracking of the glass layer 53 can be suppressed.

[0042] The above-described embodiment contemplates the following configuration: (1) A solar cell module 100 including an electrically conductive layer 2 disposed on a substrate 1, perovskite solar cell elements 3 disposed on the conductive layer 2, electrodes 4 disposed on the perovskite solar cell elements 3, and an encapsulant layer 5 that encapsulates the perovskite solar cell elements 3 and the electrodes 4, wherein the encapsulant layer 5 has at least one hydrophilic base layer 51, one intermediate layer 52 that is hydrophilic and peelable and made of a non-silicon-based material, and one glass layer 53, and the intermediate layer 52 is disposed between the base layer 51 and the glass layer 53.

[0043] According to this configuration, the perovskite solar cell element 3 and the electrode 4 are sealed by the sealing material layer 5 having the glass layer 53, thereby isolating them from the atmosphere and improving the durability of the solar cell module 100. Furthermore, the peelable intermediate layer 52 is disposed between the base layer 51 and the glass layer 53, so that the glass layer 53 and the intermediate layer 52 are not adhered to each other. Therefore, even if the solar cell module 100 is subjected to a thermal cycle, the base layer 51 and the intermediate layer 52 can deform independently of the glass layer 53, and stresses associated with deformation of the base layer 51 and the intermediate layer 52 do not act on the glass layer 53, thereby suppressing cracking of the glass layer 53. In other words, the intermediate layer 52 acts as a stress relaxation layer, resulting in a solar cell module 100 with a highly durable glass layer 53.

[0044] Furthermore, because the intermediate layer 52 is hydrophilic, it can be easily provided on the hydrophilic base layer 51, eliminating the need for a hydrophilic treatment to form the glass layer 53 on the base layer 51. This simplifies the manufacturing process for the solar cell module 100, improving productivity and reducing production costs. Furthermore, because the intermediate layer 52 is made of a non-silicon material, it is possible to suppress the diffusion and migration of Si, thereby preventing the deterioration of the functionality of the solar cell module 100 over long-term use.

[0045] (2) In the solar cell module 100 of (1), it is preferable to further include a sealing portion 6 that covers the outer edge of the sealing material layer 5 and seals the perovskite solar cell element 3 and the electrode 4.

[0046] According to this configuration, the outer edge of the sealing material layer 5 can be reliably sealed, and therefore the durability of the solar cell module 100 can be improved.

[0047] (3) In the solar cell module 100 of (1) or (2), when viewed in a plan view, it is preferable that the area of ​​the glass layer 53 is larger than the area of ​​the base layer 51 and the intermediate layer 52, and that the glass layer 53 is adhered to the conductive layer 2 at the outer edge of the sealing material layer 5.

[0048] According to this configuration, the perovskite solar cell element 3 and the electrode 4 can be sealed by the glass layer 53, eliminating the need for a sealing portion 6 for sealing the outer edge of the sealing material layer 5 and reducing the area in which the sealing portion 6 is disposed. This increases the amount of power generated by the solar cell module 100 per unit area. Furthermore, because the process for disposing the sealing portion 6 can be omitted, the production efficiency of the solar cell module 100 can be improved and the production costs can be reduced.

[0049] Other Embodiments (a) As shown in Fig. 5 , the encapsulant layer 5 may have a plurality of base layers 51, intermediate layers 52, and glass layers 53. In the example shown in Fig. 5 , the base layer 51, intermediate layer 52, glass layer 53, intermediate layer 52, base layer 51, intermediate layer 52, and glass layer 53 are stacked in this order on the electrode 4. By forming the encapsulant layer 5 from a plurality of layers, the durability of the solar cell module 100 can be improved.

[0050] (b) As shown in Fig. 6 , an adhesive layer 7 may be disposed between the sealant layer 5 and the conductive layer 2. The adhesive layer 7 is, for example, an insulating adhesive tape, and is disposed so as to surround the outer periphery of the solar cell 10 in a plan view, at a position spaced outward from the outer periphery of the solar cell 10. In the example shown in Fig. 6 , the sealant layer 5 has an intermediate layer 52, a base layer 51, another intermediate layer 52, and a glass layer 53 laminated in this order toward the Z1 side.

[0051] The adhesive layer 7 is disposed between the sealing material layer 5 and the conductive layer 2, thereby enabling the perovskite solar cell element 3 to be reliably sealed. Furthermore, the intermediate layer 52 is provided between the adhesive layer 7 and the base layer 51, preventing adhesion between the adhesive layer 7 and the intermediate layer 52, thereby reducing stress acting on the adhesive layer 7 from the base layer 51 and the intermediate layer 52 due to thermal cycling. Furthermore, the glass layer 53 and the adhesive layer 7 are bonded to each other at the outer edge of the sealing material layer 5, so that the perovskite solar cell element 3 is also sealed by the glass layer 53. This eliminates the need for a sealing section 6 for sealing the outer edge of the sealing material layer 5, reducing the area in which the sealing section 6 is disposed and increasing the amount of power generated by the solar cell module 100 per unit area.

[0052] (c) The solar cell module 100 may be protected by a protective layer (not shown). The protective layer may be provided so as to cover the encapsulant layer 5, and may include a primary encapsulating layer that encapsulates the perovskite solar cell elements 3 and prevents moisture from entering from the outside, and a secondary encapsulating layer that is disposed on top of the primary encapsulating layer and has weather resistance.

[0053] The present disclosure is applicable to solar cell modules having perovskite solar cell elements and methods for manufacturing solar cell modules.

[0054] 1: substrate, 2: conductive layer, 3: perovskite solar cell element, 4: electrode, 5: sealing material layer, 6: sealing portion, 51: base layer, 52: intermediate layer, 53: glass layer, 100: solar cell module

Claims

1. A solar cell module comprising: an electrically conductive layer disposed on a substrate; perovskite solar cell elements disposed on the conductive layer; electrodes disposed on the perovskite solar cell elements; and an encapsulant layer that encapsulates the perovskite solar cell elements and the electrodes, wherein the encapsulant layer has at least one hydrophilic base layer, one intermediate layer that is hydrophilic and peelable and made of a non-silicon-based material, and one glass layer, and the intermediate layer is disposed between the base layer and the glass layer.

2. The solar cell module according to claim 1, further comprising a sealing portion that covers the outer edge of the sealing material layer and seals the perovskite solar cell element and the electrodes.

3. A solar cell module as described in claim 1 or 2, wherein, in a plan view, the area of ​​the glass layer is larger than the areas of the base layer and the intermediate layer, and the glass layer is adhered to the conductive layer at the outer edge of the sealing material layer.

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