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

Abstract

This disclosure provides a solar cell capable of suppressing light reflection and increasing the amount of light incident on the photoelectric conversion layer, a surface plate for a solar cell, and a method for manufacturing a solar cell. [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, and a reflection suppression layer 50 located on the light-receiving surface of the surface plate 40, wherein the reflection suppression layer 50 comprises first nanoparticles 51 and second nanoparticles 52 arranged on the light-receiving side of the first nanoparticles 51, and the refractive index of the second nanoparticles 52 is smaller than the refractive index of the first nanoparticles 51.

Description

Technical Field

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

[0005] The present disclosure has been made to solve such problems, and provides a solar cell, a surface plate for a solar cell, and a method for manufacturing a solar cell that can suppress light reflection and increase the amount of light incident on the photoelectric conversion layer.

Means for Solving the Problems

[0006] The solar cell according to this disclosure comprises a solar cell, a transparent surface plate located on the light-receiving surface side of the solar cell, and a reflection suppression layer located on the light-receiving surface of the surface plate, wherein the reflection suppression layer comprises a first nanoparticle and a second nanoparticle disposed on the light-receiving side of the first nanoparticle, and the refractive index of the second nanoparticle is smaller than the refractive index of the first nanoparticle.

[0007] The specific gravity of the second nanoparticle may be less than that of the first nanoparticle.

[0008] The first nanoparticle may be a nanoparticle containing one selected from the group consisting of SiO2, Al2O3, Y2O3, and ZrO2, and the second nanoparticle may be a nanoparticle containing one different from the first nanoparticle, selected from the group.

[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, and comprises a reflection suppression layer located on the light-receiving surface of the surface plate, the reflection suppression layer comprising a first nanoparticle and a second nanoparticle disposed on the light-receiving side of the first nanoparticle, the refractive index of the second nanoparticle being smaller than the refractive index of the first nanoparticle.

[0010] A method for manufacturing a solar cell according to this disclosure comprises the steps of: applying a dispersion containing at least first nanoparticles and second nanoparticles onto a transparent surface plate provided on the light-receiving surface side of a solar cell; and drying the dispersion, wherein the refractive index of the second nanoparticles is smaller than that of the first nanoparticles, and the specific gravity of the second nanoparticles is smaller than that of the first nanoparticles. [Effects of the Invention]

[0011] This disclosure provides a solar cell capable of suppressing light reflection and increasing the amount of light incident on the photoelectric conversion layer, a surface plate for a solar cell, and a method for manufacturing a solar cell. [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 view of the side cross-section of the surface plate and the anti-reflective layer. [Figure 3] This figure shows the relationship between wavelength and refractive index in each nanoparticle. [Figure 4] 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 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, and a reflection suppression layer 50.

[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, and reflection suppression layer 50 are stacked in the solar cell 1 is defined as the z-axis direction. Furthermore, in the following explanation, the z-positive direction side will be defined as the light-receiving side of the solar cell 1.

[0016] The solar cell 10 is a photoelectric conversion element formed, for example, as a thin rectangular plate in an xy-plane view. The top surface of the solar cell 10 (the surface on the z-positive side) is the light-receiving surface. Although Figure 1 shows an example in which a sealing material 20 is interposed between the solar cell 10 and the surface plate 40, the solar cell 10 may also be formed directly on the surface of the surface plate 40 (the surface on the z-negative side). The number of solar cells 10 arranged in the solar cell 1 is not particularly limited. If there are multiple solar cells 10, the multiple solar cells 10 are arranged in the solar cell 1, for example, in the xy-plane direction.

[0017] The solar cell 10 can be constructed using photoelectric conversion elements such as silicon-based single crystal type, silicon-based polycrystalline type, amorphous silicon type, thin-film silicon type, CIGS type, organic thin-film type, dye-sensitized type, and perovskite type. 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 stacked. In this case, the photoelectric conversion layer may contain an organic-inorganic perovskite compound.

[0018] The encapsulant 20 is a resin layer that covers and protects the solar cell 10. The encapsulant 20 is made of a transparent material such as ethylene vinyl acetate (EVA), polyvinyl butyral (PVB), polyolefin resin, ionomer resin, or silicon resin. As shown in Figure 1, the encapsulant 20 is sandwiched between a back plate 30 and a 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, but 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 conform to the three-dimensional shape of, for example, the 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. Hereinafter, the reflection suppression layer 50 will be described in detail with reference to FIG. 2. FIG. 2 is an enlarged side cross-sectional view of the front plate and the reflection suppression layer.

[0022] As shown in FIG. 2, the reflection suppression layer 50 includes a plurality of first nanoparticles 51 and a plurality of second nanoparticles 52, respectively. The first nanoparticles 51 are arranged on the light-receiving surface of the front plate 40. The second nanoparticles 52 are arranged on the light-receiving side of the first nanoparticles 51. Thus, by providing an uneven shape formed by nanoparticles on the light-receiving surface of the front plate 40, the solar cell 1 can suppress the light reflection in the front plate 40.

[0023] Here, the refractive index of the second nanoparticle 52 is smaller than that of the first nanoparticle 51. In this way, by gradually increasing the refractive index of the reflection suppression layer 50 from the light-receiving side (the z-axis positive direction side), the solar cell 1 can further suppress light reflection on the surface plate 40. Note that the nanoparticles provided in the reflection suppression layer 50 are not limited to two types, the first nanoparticle 51 and the second nanoparticle 52, but may be three or more types.

[0024] Figure 3 shows the relationship between wavelength and refractive index for each nanoparticle. The nanoparticles provided in the reflection suppression layer 50 are inorganic nanoparticles made of, for example, an insulator or a semiconductor. More specifically, the nanoparticles provided in the reflection suppression layer 50 may be inorganic nanoparticles containing one selected from the group consisting of SiO2, Al2O3, Y2O3, and ZrO2 as shown in Figure 3. That is, the first nanoparticle 51 is an inorganic nanoparticle containing one selected from the group consisting of SiO2, Al2O3, Y2O3, and ZrO2. The second nanoparticle 52 is an inorganic nanoparticle containing one different from the first nanoparticle 51, selected from the group consisting of SiO2, Al2O3, Y2O3, and ZrO2. For example, if the first nanoparticle 51 is ZrO2, the second nanoparticle 52 is selected from Al2O3, Y2O3, and ZrO2.

[0025] Furthermore, the nanoparticles provided in the reflection suppression layer 50 may be selected such that the specific gravity of the second nanoparticles 52 is lower than that of the first nanoparticles 51. The reflection suppression layer 50 is formed by coating the surface plate 40 with a dispersion in which the first nanoparticles 51 and the second nanoparticles 52 are dispersed in a solvent, and then drying the solvent. In this dispersion coated on the surface plate 40, nanoparticles with a higher specific gravity are deposited on the surface plate 40 first. Therefore, the first nanoparticles 51 are deposited on the surface plate 40, and the second nanoparticles 52, which have a lower specific gravity than the first nanoparticles 51, are deposited on top of the first nanoparticles 51.

[0026] <Method of manufacturing solar cells> Next, a method for manufacturing a solar cell according to Embodiment 1 will be described. Figure 4 is a flowchart of the method for manufacturing a solar cell according to Embodiment 1.

[0027] First, a dispersion containing at least first nanoparticles 51 and second nanoparticles 52 is applied to the surface plate 40 (step S101). Here, if the specific gravity of the second nanoparticles 52 is less than the specific gravity of the first nanoparticles 51, the first nanoparticles 51 and second nanoparticles 52 are deposited from the top surface of the surface plate 40 in the order of first nanoparticles 51 and second nanoparticles 52. Also, as described above, the nanoparticles contained in the dispersion are not limited to two types, first nanoparticles 51 and second nanoparticles 52, but may be three or more types. Furthermore, in addition to nanoparticles and a solvent, the dispersion may also contain a protective agent for dispersing the nanoparticles in the solvent.

[0028] Next, the dispersion is dried (step S102). This forms a reflection suppression layer 50 comprising first nanoparticles 51 and second nanoparticles 52 on the surface plate 40. In the reflection suppression layer 50, the first nanoparticles 51 are arranged on the surface plate 40, and the second nanoparticles 52, which have a refractive index smaller than that of the first nanoparticles 51, are arranged on the light-receiving side of the first nanoparticles 51. Thus, a reflection suppression layer 50 is formed on the surface plate 40 in which the refractive index gradually increases from the light-receiving side.

[0029] 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 is 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.

[0030] As described above, the solar cell 1 according to this embodiment 1 includes a reflection suppression layer 50 having first nanoparticles 51 and second nanoparticles 52 on the light-receiving surface of the surface plate 40. In the reflection suppression layer 50, the first nanoparticles 51 are arranged on the surface plate 40, and the second nanoparticles 52, which have a refractive index smaller than that of the first nanoparticles 51, are arranged on the light-receiving side of the first nanoparticles 51. By increasing the refractive index of the reflection suppression layer 50 in stages from the light-receiving side in this way, 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.

[0031] 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]

[0032] 1. Solar cell 10 solar cells 20 Sealing material 30 Back plate 40 Surface plate 50 Anti-reflection layer 51 First Nanoparticle 52 Second Nanoparticle

Claims

1. Solar cells and A transparent surface plate located on the light-receiving side of the solar cell, The surface plate comprises a reflection suppression layer located on the light-receiving surface, The reflection suppression layer 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. Solar cell.

2. The specific gravity of the second nanoparticle is less than that of the first nanoparticle. The solar cell according to claim 1.

3. The first nanoparticle is SiO ２ Al ２ O ３ , Y ２ O ３ , ZrO ２ A nanoparticle comprising one selected from the group consisting of, The second nanoparticle is a nanoparticle that includes one type different from the first nanoparticle, selected from the group. 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, The surface plate is equipped with a reflection suppression layer located on the light-receiving surface, The reflection suppression layer 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. Surface plate for solar cells.

5. The steps include: applying a dispersion containing at least first nanoparticles and second nanoparticles onto a transparent surface plate provided on the light-receiving side of a solar cell; The process includes the step of drying the dispersion, The refractive index of the second nanoparticle is smaller than that of the first nanoparticle. The specific gravity of the second nanoparticle is less than that of the first nanoparticle. A method for manufacturing solar cells.

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