Solar cell, surface plate for solar cell, and method for manufacturing a solar cell

Abstract

This disclosure provides a solar cell and a surface plate for a solar cell that can suppress light reflection and increase the amount of light incident on the photoelectric conversion layer. [Solution] The solar cell according to this disclosure comprises a solar cell 10, a transparent surface plate 40 located on the light-receiving surface side of the solar cell 10, a reflection suppression layer 50 containing nanoparticles 51 located on the light-receiving surface of the surface plate 40, and a protective layer 60 located on the light-receiving surface of the reflection suppression layer 50, wherein the refractive index of the protective layer 60 is greater than or equal to the refractive index of air and less than or equal to the refractive index of the reflection suppression layer 50.

Description

Technical Field

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[0001] The present disclosure relates to a solar cell, a surface plate for a solar cell, and a method for manufacturing a solar cell.

Background Art

[0002] In order to improve the power generation efficiency of a solar cell, it is important to increase the amount of light incident on the photoelectric conversion layer. As one method for achieving this purpose, for example, Patent Document 1 discloses a technique for suppressing the amount of light reflected on the surface of a transparent conductive layer. In Patent Document 1, the surface of the transparent conductive layer is made into a concavo-convex structure by wet etching, thereby suppressing the amount of light reflected on the surface of the transparent conductive layer.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] There is a need for a technique for suppressing light reflection in a solar cell, not limited to the method disclosed in Patent Document 1.

[0005] The present disclosure has been made to solve such problems, and provides a solar cell and a surface plate for a solar cell capable of suppressing light reflection and increasing the amount of light incident on the photoelectric conversion layer.

Means for Solving the Problems

[0006] The solar cell according to the present disclosure includes a solar cell, a transparent surface plate located on the light-receiving surface side of the solar cell, a reflection suppression layer containing nanoparticles located on the light-receiving surface of the surface plate, and a protective layer located on the light-receiving surface of the reflection suppression layer, and the refractive index of the protective layer is not less than the refractive index of air and not more than the refractive index of the reflection suppression layer.

[0007] The aforementioned nanoparticles may be inorganic nanoparticles containing one selected from the group consisting of SiO2, Al2O3, Y2O3, and ZrO2.

[0008] The nanoparticle comprises a first nanoparticle and a second nanoparticle disposed on the light-receiving side of the first nanoparticle, wherein the refractive index of the second nanoparticle may be smaller than that of the first nanoparticle.

[0009] The surface plate for a solar cell according to this disclosure is a transparent surface plate provided on the light-receiving surface side of a solar cell in a solar cell, comprising a reflection suppression layer located on the light-receiving surface of the surface plate and a protective layer located on the light-receiving surface of the reflection suppression layer, wherein the refractive index of the protective layer is greater than or equal to the refractive index of air and less than or equal to the refractive index of the reflection suppression layer.

[0010] A method for manufacturing a solar cell according to this disclosure comprises the steps of: applying a dispersion containing nanoparticles to a transparent surface plate provided on the light-receiving surface side of a solar cell, drying the dispersion to form a reflection-suppressing layer containing the nanoparticles; and forming a protective layer on the reflection-suppressing layer by coating or lamination, wherein the refractive index of the protective layer is greater than or equal to the refractive index of air and less than or equal to the refractive index of the reflection-suppressing layer. [Effects of the Invention]

[0011] This disclosure provides a solar cell and a surface plate for a solar cell that can suppress light reflection and increase the amount of light incident on the photoelectric conversion layer. [Brief explanation of the drawing]

[0012] [Figure 1] This is a side cross-sectional view of a solar cell according to Embodiment 1. [Figure 2] This is an enlarged side cross-sectional view of a surface plate provided with an anti-reflective layer and a protective layer. [Figure 3] This figure shows the relationship between wavelength and refractive index in each nanoparticle. [Figure 4]This is an enlarged side cross-sectional view of another example of a surface plate provided with an anti-reflective layer and a protective layer. [Figure 5] This is an enlarged side cross-sectional view of a surface plate provided with an anti-reflective layer and another example of a protective layer. [Figure 6] This is a flowchart of the manufacturing method for a solar cell according to Embodiment 1. [Modes for carrying out the invention]

[0013] The following describes specific embodiments of this disclosure in detail with reference to the drawings. However, this disclosure is not limited to the following embodiments. Also, for clarity, the following descriptions and drawings have been simplified as appropriate.

[0014] (Embodiment 1) <Solar cell configuration> First, the configuration of the solar cell according to this embodiment 1 will be described with reference to Figure 1. Figure 1 is a side cross-sectional view of the solar cell according to this embodiment 1. As shown in Figure 1, the solar cell 1 comprises a solar cell 10, a sealing material 20, a back plate 30, a front plate 40, a reflection suppression layer 50, and a protective layer 60.

[0015] In the following explanation, the xyz 3D Cartesian coordinate system will be used as appropriate. In this embodiment 1, the direction in which the solar cell 10, encapsulant 20, back plate 30, front plate 40, reflection suppression layer 50, and protective layer 60 are stacked in the solar cell 1 is defined as the z-axis direction. Furthermore, in the following explanation, the z-positive direction will be defined as the light-receiving side of the solar cell 1.

[0016] The solar cell 10 is a photoelectric conversion element formed in a thin plate shape having, for example, a rectangular shape in plan view in the xy plane. The upper surface (the surface on the +z-axis direction side) of the solar cell 10 is a light-receiving surface. Note that FIG. 1 shows an example in which the sealing material 20 is interposed between the solar cell 10 and the front plate 40, but the solar cell 10 may be formed directly on the surface (the surface on the -z-axis direction side) of the front plate 40. The number of solar cells 10 arranged in the solar cell 1 is not particularly limited. When there are a plurality of solar cells 10, the plurality of solar cells 10 are arranged, for example, in the xy plane direction in the solar cell 1.

[0017] The solar cell 10 can be configured using a photoelectric conversion element such as a silicon-based single crystal type, a silicon-based polycrystal type, an amorphous silicon type, a thin film silicon type, a CIGS type, an organic thin film type, a dye-sensitized type, a perovskite type, or the like. In the case of a perovskite-based photoelectric conversion element, the solar cell 10 has a structure in which a substrate, a transparent electrode, an electron transport layer, a photoelectric conversion layer, a hole transport layer, and a back electrode are laminated. In this case, the photoelectric conversion layer may contain an organic-inorganic perovskite compound.

[0018] The sealing material 20 is a resin layer that covers and protects the solar cell 10. The sealing material 20 is composed of a transparent material such as, for example, ethylene vinyl acetate (EVA) resin, polyvinyl butyral (PVB), polyolefin resin, ionomer resin, or silicon resin. As shown in FIG. 1, the sealing material 20 is sandwiched between the back plate 30 and the front plate 40.

[0019] The back plate 30 covers the lower surface (the surface on the minus z-axis direction side) of the sealing material 20 and protects the solar cell 10. The back plate 30 is not particularly limited, and for example, it is a member formed in a layered, film-like, or plate-like shape from polyethylene terephthalate (PET), polycarbonate resin, acrylic resin, glass, metal (such as aluminum), etc. Further, the back plate 30 may be processed into a curved surface shape so as to follow the three-dimensional shape of an object (such as the wall surface of a building or the roof of a vehicle) to which the solar cell 1 is attached.

[0020] The front plate 40 is located on the light-receiving surface side of the solar cell 10 in the solar cell 1. More specifically, the front plate 40 covers the light-receiving surface (the surface on the plus z-axis direction side) of the sealing material 20 and protects the solar cell 10. The front plate 40 is a member formed in a layered, film-like, or plate-like shape from a transparent material such as polycarbonate resin, acrylic resin, or glass. The space between the front plate 40 and the sealing material 20 and the space between the back plate 30 and the sealing material 20 are adhered, for example, by the adhesive force of the sealing material 20.

[0021] The reflection suppression layer 50 is located on the light-receiving surface (the surface on the plus z-axis direction side) of the front plate 40. The reflection suppression layer 50 covers the light-receiving surface of the front plate 40 and suppresses the light reflection of the solar cell 1. The details of the reflection suppression layer 50 will be described later.

[0022] The protective layer 60 is located on the light-receiving surface (the surface on the plus z-axis direction side) of the reflection suppression layer 50. The protective layer 60 covers the light-receiving surface of the reflection suppression layer 50 and suppresses the deterioration of the reflection suppression layer 50. The details of the protective layer 60 will be described later.

[0023] <Configuration of the reflection suppression layer 50 and the protective layer 60> The configurations of the reflection suppression layer 50 and the protective layer 60 will be described below with reference to Figures 2 to 5. Figure 2 is an enlarged side cross-sectional view of a surface plate provided with the reflection suppression layer and the protective layer. Figure 3 is a diagram showing the relationship between wavelength and refractive index in each nanoparticle. Figure 4 is an enlarged side cross-sectional view of a surface plate provided with another example of the reflection suppression layer and protective layer. Figure 5 is an enlarged side cross-sectional view of a surface plate provided with the reflection suppression layer and another example of the protective layer.

[0024] As shown in Figure 2, the reflection suppression layer 50 contains nanoparticles 51. The nanoparticles 51 are arranged on the light-receiving surface of the surface plate 40. This creates an uneven surface on the light-receiving surface of the surface plate 40. The uneven surface created by the nanoparticles 51 allows the solar cell 1 to suppress light reflection on the surface plate 40.

[0025] Figure 3 shows the relationship between wavelength and refractive index in each nanoparticle. Nanoparticle 51 is an inorganic nanoparticle made of, for example, an insulator or semiconductor. More specifically, nanoparticle 51 may be an inorganic nanoparticle containing one selected from the group consisting of SiO2, Al2O3, Y2O3, and ZrO2 shown in Figure 3.

[0026] The nanoparticles 51 provided in the reflection suppression layer 50 are not limited to one type but may be of multiple types. In the example shown in Figure 4, the reflection suppression layer 50 includes first nanoparticles 511 and second nanoparticles 512. The first nanoparticles 511 are arranged on the light-receiving surface of the surface plate 40. The second nanoparticles 512 are arranged on the light-receiving side (positive side in the z-axis direction) of the first nanoparticles 511.

[0027] The refractive index of the second nanoparticle 512 is smaller than that of the first nanoparticle 511. That is, the first nanoparticle 511 is an inorganic nanoparticle containing one selected from the group consisting of SiO2, Al2O3, Y2O3, and ZrO2 shown in Figure 3. The second nanoparticle 512 is an inorganic nanoparticle containing one different from the first nanoparticle 511, selected from the group consisting of SiO2, Al2O3, Y2O3, and ZrO2 shown in Figure 3. For example, if the first nanoparticle 511 is ZrO2, the second nanoparticle 512 can be selected from Al2O3, Y2O3, and ZrO2. In this way, by gradually increasing the refractive index of the reflection suppression layer 50 from the light-receiving side (positive z-axis direction side), the solar cell 1 can further suppress light reflection at the surface plate 40.

[0028] As explained above, by arranging the reflection suppression layer 50, on which nanoparticles 51 are deposited, on the light-receiving surface of the surface plate 40, the solar cell 1 can suitably suppress light reflection on the surface plate 40 and increase the amount of light incident on the photoelectric conversion layer. However, if nanoparticles 51 are simply arranged on the surface plate 40, there is a risk that the nanoparticles 51 may peel off from the surface plate 40 due to friction or deteriorate over time. In addition, if the nanoparticles are contaminated with dust or other debris and foreign matter gets trapped between them, the light reflection suppression effect of the reflection suppression layer 50 may decrease.

[0029] Therefore, in this disclosure, a protective layer 60 is placed on the light-receiving surface (the surface on the z-axis positive side) of the reflection suppression layer 50. The refractive index of the protective layer 60 is greater than or equal to the refractive index of air and less than or equal to the refractive index of the reflection suppression layer 50. If the nanoparticles 51 are selected from the group consisting of SiO2, Al2O3, Y2O3, and ZrO2 as shown in Figure 3, a material with a refractive index in the range of 1 to 2.4 is selected as the protective layer 60. By covering the light-receiving surface of the reflection suppression layer 50 with the protective layer 60, the solar cell 1 can suppress the degradation of the reflection suppression layer 50 while maintaining the light reflection suppression effect of the reflection suppression layer 50.

[0030] The material of the protective layer 60 may be embedded between the nanoparticles 51, as shown in Figures 2, 4, and 5. Furthermore, as shown in Figure 5, the light-receiving surface of the protective layer 60 may be formed in a shape that conforms to the shape of the nanoparticles 51. The material of the protective layer 60 may include, but is not limited to, UV-curing resins such as acrylic resin or epoxy resin, or thermoplastic resins such as polyethylene or nylon.

[0031] <Method of manufacturing solar cells> Next, a method for manufacturing a solar cell according to Embodiment 1 will be described. Figure 6 is a flowchart of the method for manufacturing a solar cell according to Embodiment 1.

[0032] First, a reflection suppression layer 50 is formed on the surface plate 40 (step S101). More specifically, a dispersion containing nanoparticles 51 is first applied to the surface plate 40. As mentioned above, the dispersion may contain two or more types of nanoparticles 51. In addition to the nanoparticles 51 and the solvent, the dispersion may also contain a protective agent for dispersing the nanoparticles 51 in the solvent. The dispersion is dried to form a reflection suppression layer 50 containing nanoparticles 51 on the surface plate 40.

[0033] Next, a protective layer 60 is formed on the anti-reflection layer 50 (step S102). Examples of methods for forming the protective layer 60 include coating and lamination. In the case of coating, a solution of the material for the protective layer 60 is applied to the anti-reflection layer 50 and the solution is cured. In this method, by using an ultraviolet-curing resin such as acrylic resin or epoxy resin as the material for the protective layer 60, the solution can be cured quickly, and deformation of the nanoparticles 51 in the anti-reflection layer 50 can be suppressed.

[0034] In the case of lamination, a flexible film is bonded to the anti-reflective layer 50 as a protective layer 60. Lamination methods include, for example, vacuum lamination and press lamination. The flexible film used as the protective layer 60 may be made of a thermoplastic resin such as polyethylene or nylon.

[0035] Finally, the solar cell 10 and the encapsulant 20 are sandwiched between the back plate 30 and the front plate 40 to form the solar cell 1 (step S103). The front plate 40 is positioned so that the side on which the reflection suppression layer 50 and the protective layer 60 are formed faces outwards. After the solar cell 10 and the encapsulant 20 for sealing the solar cell 10 are sandwiched between the back plate 30 and the front plate 40, the solar cell 1 may be formed by, for example, applying pressure to both sides and then heating.

[0036] As described above, the solar cell 1 according to this embodiment 1 has a protective layer 60 on the light-receiving surface of the reflection suppression layer 50, the protective layer 60 having a refractive index greater than or equal to that of air and less than or equal to that of the reflection suppression layer 50. By covering the light-receiving surface of the reflection suppression layer 50 with the protective layer 60 having a refractive index within this range, the solar cell 1 can maintain the reflection suppression effect of the reflection suppression layer 50 while suppressing the degradation of the reflection suppression layer 50. The solar cell 1 provided with the reflection suppression layer 50 and the protective layer 60 can suitably suppress light reflection on the surface plate 40 and increase the amount of light incident on the photoelectric conversion layer.

[0037] It should be noted that the present invention is not limited to the embodiments described above, and can be modified as appropriate without departing from the spirit of the invention. [Explanation of Symbols]

[0038] 1. Solar cell 10 solar cells 20 Sealing material 30 Back plate 40 Surface plate 50 Anti-reflection layer 51 nanoparticles 60 protective layer 511 First nanoparticle 512 Second Nanoparticle

Claims

1. Solar cells and A transparent surface plate located on the light-receiving side of the solar cell, A reflection suppression layer containing nanoparticles is located on the light-receiving surface of the aforementioned surface plate, The reflection suppression layer comprises a protective layer located on the light-receiving surface, The refractive index of the protective layer is greater than or equal to that of air, and less than or equal to that of the reflection-suppressing layer. Solar cell.

2. The aforementioned nanoparticles are SiO ２ Al ２ O ３ , Y ２ O ３ , ZrO ２ It is an inorganic nanoparticle containing one selected from the group consisting of the following: The solar cell according to claim 1.

3. The nanoparticle comprises a first nanoparticle and a second nanoparticle disposed on the light-receiving side of the first nanoparticle. The refractive index of the second nanoparticle is smaller than that of the first nanoparticle. The solar cell according to claim 1 or 2.

4. A transparent surface plate provided on the light-receiving side of a solar cell in a solar cell, A reflection suppression layer located on the light-receiving surface of the surface plate, The reflection suppression layer comprises a protective layer located on the light-receiving surface, The refractive index of the protective layer is greater than or equal to that of air, and less than or equal to that of the reflection-suppressing layer. Surface plate for solar cells.

5. The steps include: applying a dispersion containing nanoparticles to a transparent surface plate provided on the light-receiving side of a solar cell, drying the dispersion to form a reflection-suppressing layer containing the nanoparticles; The process includes the step of forming a protective layer on the anti-reflective layer by coating or lamination, The refractive index of the protective layer is greater than or equal to that of air, and less than or equal to that of the reflection-suppressing layer. A method for manufacturing solar cells.

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