Photovoltaic power generation system

Abstract

To efficiently perform space-saving photovoltaic power generation.SOLUTION: A photovoltaic power generation system 10 includes a light collecting unit 100 that has a parabolic reflecting surface 101 formed by adjacently arranging a plurality of reflecting mirrors that reflect sunlight and in which a focal point P1 of reflection light is set above the reflecting surface 101, and a solar battery 200 that includes a predetermined photoelectric conversion element and is installed at a position closer to the reflecting surface 101 than the focal point MR1 within a light collecting region P1 by the light collecting unit 100. The solar cell 200 is a concentrator solar cell.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a photovoltaic power generation system that generates power using sunlight. [Background technology]

[0002] Conventionally, there are technologies for generating electricity using sunlight. For example, a solar power generation device has been proposed in which solar cells are arranged on the upper surface of a plate-like structure, and a number of solar cell arrays are spread out flat on a support structure to generate solar power (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 10-125945 Summary of the Invention [Problem to be solved by the invention]

[0004] The above-described conventional technology allows for power generation using a large light-receiving area of ​​a large number of solar cell arrays, such as on the rooftop of a building where sunlight is readily received. When using such flat-type batteries, it is necessary to secure an installation space for the flat-type batteries. Furthermore, for example, when a large amount of power is required, it is necessary to secure a large installation space according to the required power and to install a large number of flat-type batteries in that installation space. In other words, since a large installation space and a large number of flat-type batteries are required, the manufacturing costs and installation costs of the solar power generation system increase. Therefore, it is important to efficiently generate solar power in a small space, even when a large amount of power is required.

[0005] An object of the present invention is to efficiently generate solar power in a space-saving manner. [Means for solving the problem]

[0006] A solar power generation system according to one aspect of the present invention includes a concentrating unit having a parabolic reflective surface formed by arranging a plurality of adjacent reflectors that reflect sunlight, with the focal point of the reflected light being set above the reflective surface, and a solar cell including a predetermined photoelectric conversion element and installed within the light concentration area of ​​the concentrating unit and closer to the reflective surface than the focal point. The solar cell is a concentrating solar cell. [Effects of the Invention]

[0007] According to the present invention, solar power generation can be performed efficiently in a space-saving manner. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a perspective view showing a schematic configuration example of a solar power generation system. [Figure 2] FIG. 2 is a cross-sectional view showing a schematic configuration example of a solar power generation system. [Figure 3] FIG. 3 is a top view showing a schematic configuration example of a light collecting unit that constitutes a solar power generation system. [Figure 4] FIG. 4 is a diagram showing an example of the external configuration when a plurality of photovoltaic power generation systems are installed. [Figure 5] FIG. 5 is a perspective view showing a schematic configuration example in which a light collecting section is formed by connecting approximately triangular reflecting mirrors. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.

[0010] [Configuration example of information processing device] Fig. 1 is a perspective view showing a schematic configuration example of a solar power generation system 10. Fig. 2 is a cross-sectional view showing a schematic configuration example of the solar power generation system 10. Fig. 3 is a top view showing a schematic configuration example of a concentrating unit 100 constituting the solar power generation system 10. Fig. 4 is a diagram showing an external configuration example when a plurality of solar power generation systems 10 are installed. That is, Fig. 4 shows a solar power generation system group 1 composed of a plurality of solar power generation systems 10.

[0011] As shown in FIGS. 1 and 2, the solar power generation system 10 is a concentrator photovoltaic (CPV) system that generates electricity by concentrating sunlight onto a small solar cell 200 using a concentrator 100 composed of multiple reflectors M1 to M19 (see FIG. 3). That is, the solar power generation system 10 uses the concentrator 100 to concentrate sunlight and make it incident on the solar cell 200, thereby enabling the size of the semiconductor cells used as the solar cell 200 to be reduced, achieving both high conversion efficiency and low cost. While FIG. 3 shows an example in which the concentrator 100 is composed of 19 reflectors M1 to M19, the present invention is not limited to this. The concentrator 100 may also be composed of a number of reflectors other than 19. For example, FIG. 5 shows an example in which the concentrator is composed of 16 reflectors.

[0012] Specifically, the solar power generation system 10 includes a concentrator 100, a support column 150, and a solar cell 200.

[0013] The support column 150 is a rod-shaped support column that supports the concentrating unit 100 and the solar cells 200. Specifically, the lower part of the support column 150 is fixed to the installation location (e.g., the ground) of the solar power generation system 10. This fixing method can be performed using known fixing means. The support column 150 is configured to penetrate the concentrating unit 100 in the vertical direction to fix the concentrating unit 100, and to fix the solar cells 200 to the upper end. The concentrating unit 100 and the solar cells 200 to the support column 150 can be fixed using known fixing means. A power path (lead-out path) is formed within the support column 150 to output the power generated by the solar cells 200 to the controller 300. The support column 150 is preferably made of a material that has a high heat resistance temperature and is strong enough to support the concentrating unit 100 and the solar cells 200. For example, the support column 150 can be made of iron, ceramic, resin, concrete, or other materials.

[0014] [Example of light collection section configuration] As shown in Fig. 2, the light concentrating unit 100 is a polygonal reflecting mirror having a roughly cone shape that reflects sunlight and makes it incident on the solar cell 200. Specifically, the light concentrating unit 100 has a parabolic reflecting surface 101 formed by arranging a plurality of reflecting mirrors M1 to M19 that reflect sunlight adjacent to each other, and a focus P1 of the reflected light is set above the reflecting surface 101. In Figs. 1 and 2, the reflected light RL1 from the plurality of reflecting mirrors M1 to M19 is schematically indicated by dotted arrows.

[0015] The reflecting mirrors M1 to M19 are made of a material capable of reflecting incident sunlight. The reflecting mirrors M1 to M19 can be made of a material produced by depositing a reflective material such as silver or aluminum onto a transparent material such as glass or resin (depositing the material on the surface opposite to the light incident surface). That is, the reflecting mirrors M1 to M19 can be constructed by laminating a transparent resin material and a reflective material that reflects light. By using the reflecting mirrors M1 to M19 thus deposited with a reflective material, it is possible to reflect incident sunlight with a high reflectance. The reflective material can be deposited using a known deposition method (for example, a wet method (plating method) or a dry method (vacuum film formation)). For example, by using a highly reflective material such as silver or aluminum as the reflective material, it is possible to easily and stably form the reflective material.

[0016] Here, it is assumed that the concentrating unit 100 is configured from a single large parabolic material. In this case, a large facility is required for vapor deposition of the single large parabolic material. Furthermore, since a reflective material such as silver or aluminum needs to be vapor deposited over a large area, it is expected that the vapor deposition work will be difficult. Furthermore, when a single large concentrating unit 100 is installed at the installation site of the solar power generation system 10, it is necessary to transport and lift the concentrating unit 100, which is expected to make the installation work complicated and difficult.

[0017] In contrast, when the concentrating unit 100 is composed of multiple reflectors M1-M19, no large facility is required for depositing each of these materials. Furthermore, since it is only necessary to deposit reflective materials such as silver or aluminum on a small area, the deposition process is easy. Furthermore, when installing the concentrating unit 100 composed of multiple reflectors M1-M19 at the installation site of the solar power generation system 10, the multiple small reflectors M1-M19 must be transported and lifted, but this process is considered to be easier than when installing a single large concentrating unit 100. Furthermore, since the concentrating unit 100 can be installed by connecting multiple small reflectors M1-M19, the installation process is easier.

[0018] Here, it is assumed that glass is used as the material for the reflectors M1 to M19. For example, glass is heavier than resin-based materials, so it is important to improve the efficiency of the installation work of the reflectors M1 to M19. Therefore, it is preferable to use a resin-based material, which is lighter than glass, as the material for the reflectors M1 to M19. As the resin-based material, for example, thermoplastic resins such as polyvinyl chloride (PVC) and polycarbonate (PC) or synthetic resins can be used. This makes it possible to facilitate the installation work of the light concentrating unit 100 and reduce the installation cost of the solar power generation system 10.

[0019] Various shapes can be adopted for the reflecting mirrors M1 to M19. For example, if the reflecting mirrors M1 to M19 are shaped like a circle when viewed from above, there is a risk that large gaps will be formed between adjacent reflecting mirrors M1 to M5 when the reflecting mirrors M1 to M5 are arranged adjacent to each other. Therefore, it is preferable to adopt a polygonal shape that will not create large gaps between adjacent reflecting mirrors when the reflecting mirrors M1 to M19 are arranged adjacent to each other.

[0020] For example, as shown in FIG. 3, if the reflectors M1 to M19 are shaped like a hexagon in top view, it is possible to reduce the gaps between adjacent reflectors when the reflectors M1 to M19 are arranged adjacently. This allows sunlight incident on the light-collecting surface of the light-collecting unit 100 to be collected efficiently without waste. In other words, it is possible to improve the efficiency of collecting sunlight by the light-collecting unit 100. Note that, as shown in FIG. 3, if the light-collecting unit 100 is formed by connecting 19 reflectors M1 to M19 within a circle C1 indicated by a dotted line, gaps may occur in parts of the circle C1 other than the reflectors M1 to M19. Therefore, reflectors of various shapes may be connected to fill the gaps that occur in parts of the circle C1 other than the reflectors M1 to M19. This further improves the efficiency of collecting sunlight by the light-collecting unit 100.

[0021] 3 shows an example in which the reflecting mirrors M1 to M19 are hexagonal in top view, but the reflecting mirrors M1 to M19 may also be triangular or rectangular in top view. In this case, it is also possible to reduce the gaps between adjacent reflecting mirrors. The reflecting mirrors M1 to M19 may also be circular, elliptical, or other polygonal in top view. In this case, a certain amount of gap will occur between adjacent reflecting mirrors, but it is preferable to use a shape that reduces this gap or to combine multiple reflecting mirrors of different sizes that can reduce the gaps.

[0022] Furthermore, known connecting methods can be used to connect the reflectors M1 to M19. For example, adjacent reflectors may be fixed to each other using some kind of fixing member, or adjacent reflectors may be fixed to each other using some kind of adhesive. Furthermore, multiple reflectors may be fixed to each other using reinforcing members 111 to 118. Figure 1 shows an example in which the upper surfaces of multiple reflectors are fixed to each other using reinforcing members 111 to 118, and the lower surfaces of multiple reflectors are fixed to each other using other reinforcing members.

[0023] FIG. 3 shows an example in which 19 reflectors M1 to M19 are connected to form the concentrating unit 100, but the number of reflectors is not limited to this. The size of the reflectors can also be set appropriately depending on the installation location, manufacturing location, and use location of the solar power generation system 10. For example, a relatively small reflector may be used in consideration of manufacturing costs, transportation costs, and the like. In this case, it is expected that the work time required to assemble the concentrating unit 100 at the installation location of the solar power generation system 10 will be long. On the other hand, a relatively large reflector may be used in consideration of the work time required to assemble the concentrating unit 100, and the like. In this case, there is a risk that the manufacturing costs, transportation costs, and the like of the solar power generation system 10 will increase. The size of the reflector can be set in consideration of these various circumstances. FIG. 5 shows modified examples of the reflector.

[0024] Fig. 5 is a perspective view showing a schematic configuration example of a large reflecting mirror (light-collecting portion 100a) formed by connecting approximately triangular (or approximately sector-shaped) reflecting mirrors M1a-M16a. As shown in Fig. 5, by connecting approximately triangular reflecting mirrors M1a-M16a in the circumferential direction to form the large light-collecting portion 100a, it is possible to form a reflecting surface 101 with a highly accurate circular shape. Furthermore, it is possible to eliminate the need for other reflecting materials to fill in the gaps.

[0025] In this way, a large reflector (light-collecting unit 100, 100a) can be generated by connecting multiple reflectors M1 to M19, M1a to M16a, and the sunlight concentrated by the light-collecting unit 100, 100a can be collected by the solar cell 200. This makes it possible to reduce the manufacturing costs and installation costs of the light-collecting units 100, 100a.

[0026] [Example of solar cell configuration] As shown in FIG. 2, the solar cell 200 is a solar cell including a predetermined photoelectric conversion element (power generation element). The solar cell 200 is installed within a light collection region MR1 of the light collection unit 100, closer to the reflecting surface 101 of the light collection unit 100 than the focal point P1. The solar cell 200 is arranged so that the lower surface (sunlight incident surface 201) of the solar cell 200 faces the reflecting surface 101 of the light collection unit 100. The solar cell 200 is preferably installed at a position where uniform energy is distributed on the incident surface 201 of the solar cell 200. Details of this installation position will be described later. The light collection region MR1 refers to the region through which reflected light travels from the reflecting surface 101 of the light collection unit 100 to the focal point P1. As shown in FIG. 2, the light collection region MR1 has a substantially triangular shape in a cross-sectional view, for example.

[0027] Furthermore, diameter D2 of solar cell 200 in the horizontal direction is set to be smaller than diameter D1 of concentrating section 100 in the horizontal direction. For example, as shown in Fig. 1, if solar cell 200 is configured as a circle when viewed from above, diameter D2 of solar cell 200 can be set to the diameter of solar cell 200 in the horizontal direction. For example, as shown in Fig. 1, if concentrating section 100 is configured as a circle when viewed from above, diameter D1 of concentrating section 100 can be set to the diameter of concentrating section 100 in the horizontal direction.

[0028] Generally, solar cells can be broadly classified into three types: silicon-based, compound-based, and organic-based. For example, silicon-based solar cells generate electricity using semiconductors primarily composed of silicon. For example, organic solar cells generate electricity using organic molecules, which are compounds containing carbon. For example, compound-based solar cells refer to solar cells made from materials other than silicon or organic molecules. In particular, among compound-based solar cells, compound-based multi-junction solar cells refer to solar cells with a structure in which multiple solar cells are stacked on top of each other.

[0029] For example, it is known that the conversion efficiency of silicon-based solar cells decreases as the temperature rises. Therefore, for example, if a silicon-based solar cell is installed in a portion where sunlight is concentrated, it may decompose or burn. In contrast, compound-based multi-junction solar cells are characterized by a high heat resistance temperature. Therefore, for example, even if a compound-based multi-junction solar cell is installed in a portion where sunlight is concentrated, it is possible to prevent decomposition or burning. In other words, because compound-based multi-junction solar cells have a high heat resistance temperature, it is possible to increase the conversion efficiency by concentrating sunlight using the concentrator 100.

[0030] Furthermore, for example, by using a compound-based multi-junction solar cell, light that cannot be absorbed by one power generation element can be absorbed by the power generation element below it. Therefore, by using a solar cell with a multi-layer structure, it is possible to widen the wavelength range of light that can be converted into electricity compared to silicon-based solar cells, and it is possible to increase the conversion efficiency. Therefore, in this embodiment, an example using a compound-based multi-junction solar cell is shown.

[0031] For example, it is preferable to use a compound semiconductor power generation element as the solar cell 200, which has an extremely high conversion efficiency for converting solar energy into electrical energy. By employing this compound semiconductor power generation element, it is possible to increase the conversion efficiency several times compared to, for example, a standard crystalline silicon solar cell. Furthermore, since compound semiconductor power generation elements are less susceptible to the effects of temperature, the amount of power generated is less likely to decrease even in areas with high solar radiation and high temperatures, making it possible to realize an effective power generation system.

[0032] For example, a multi-junction solar cell made of indium gallium phosphide (InGaP), gallium arsenide (GaAs), and germanium (Ge) can be used as the solar cell 200. For example, a rigid-type three-junction solar cell can be constructed by stacking InGaP as the top layer, GaAs as the middle layer, and Ge as the bottom layer. In this case, the InGaP solar cell can absorb short wavelengths, the GaAs solar cell can absorb medium wavelengths, and the Ge solar cell can absorb long wavelengths. This allows conversion over a wide wavelength range, with InGaP converting the short wavelength range of 300 to 700 nm, GaAs converting the 700 to 900 nm range, and Ge converting the long wavelength range of 900 to 1,800 nm. This allows for high conversion efficiency, making it possible to achieve high efficiency. In this way, the solar cell 200 is constructed by stacking predetermined photoelectric conversion elements.

[0033] Also, for example, a multi-junction solar cell containing at least one of indium, gallium, germanium, phosphorus, and arsenic can be used as the solar cell 200. In this case, the solar cell 200 can be constructed by stacking these power generating elements in a known stacking order.

[0034] Furthermore, for example, a multi-junction solar cell including at least one of indium gallium phosphide (InGaP), indium gallium phosphide arsenide (InGaAs), gallium arsenide (GaAs), and germanium (Ge) can be used as the solar cell 200. In this case, too, the solar cell 200 can be configured by stacking these power generating elements in a known stacking order.

[0035] Furthermore, the solar cell 200 converts the light energy concentrated by the light concentrator 100 into electrical energy (power). In this way, the power generated by the solar cell 200 is output to the controller 300 via the power path of the support column 150. The controller 300 supplies the power generated by the solar cell 200 to a supply destination 310 as needed. The supply destination 310 is, for example, a battery or a power-using device. The controller 300 may be installed inside the solar power generation system 10 or outside the solar power generation system 10.

[0036] It is preferable that the area ratio between the area S1 of the parabolic reflecting surface 101 of the light collecting section 100 and the area S2 of the incident surface 201 of the solar cell 200 be within a reasonable range. For example, the area ratio between the areas S1 and S2 can be appropriately set based on experiments, simulations, or the like within a range that can increase the light collecting efficiency.

[0037] [About the focal point of the light collecting part] For ease of explanation, an example will be shown in which sunlight is incident from a predetermined direction (for example, from the upper side in the vertical direction of FIG. 2).

[0038] As shown in FIG. 2, this embodiment shows an example in which the multiple reflecting mirrors M1 to M19 are configured so that the cross section of the light collecting unit 100 is a parabola (or an approximate parabola, the same applies below). That is, the multiple reflecting mirrors M1 to M19 are configured so that a curve K1 (see FIG. 2) virtually connecting the cross sections of the multiple reflecting mirrors M1 to M19 is a parabola. In this case, the parabola corresponding to the cross-sectional shape of the light collecting unit 100 is defined by directrixes L1 and L2 and a focus P1 of the parabola. Note that the directrixes L1 and L2 are also the radii of curvature of a circle (a circle including the parabola) corresponding to the cross-sectional shape of the light collecting unit 100. In addition, the range (light collecting region MR1) through which reflected light from the multiple reflecting mirrors M1 to M19 travels is set to be an approximate triangle in cross section. In this case, the apex of the approximate triangle corresponds to the focus P1 of the parabola. Furthermore, the light collection region MR1 through which the reflected light from the plurality of reflecting mirrors M1 to M19 travels is a cone-shaped region with the focal point P1 as its apex.

[0039] Furthermore, it is considered that the focal point P1 of the parabola is the portion of the light collection region MR1 through which the reflected light from the multiple reflectors M1 to M19 travels, where the light is most intense. Therefore, it is possible to install the solar cell 200 at the focal point P1 of the parabola. In this case, it is possible to most efficiently collect the sunlight collected by the light collection unit 100 onto the solar cell 200. However, if the solar cell 200 is installed at the focal point P1, there is a possibility that the solar cell 200 will reach the upper limit of the temperature it can withstand. For example, if the light reflected from the light collection unit 100 exceeds the upper limit of the heat resistance temperature of the solar cell 200, the solar cell 200 may decompose or burn. Therefore, in this embodiment, the solar cell 200 is installed at a position shifted downward by a distance H1 from the focal point P1 of the parabola within the light collection region MR1 through which the reflected light from each of the reflectors M1 to M19 is collected. This makes it possible to prevent the light reflected from the concentrating unit 100 from exceeding the upper limit of the heat resistance temperature of the solar cell 200, and to sufficiently collect the sunlight concentrated by the concentrating unit 100. Note that for the distance H1, a range that prevents the upper limit of the heat resistance temperature of the solar cell 200 from being reached and that can increase the light collection efficiency can be appropriately set based on experiments, simulations, etc.

[0040] Furthermore, for example, plane mirrors with flat reflecting surfaces can be used as the reflecting mirrors M1 to M19. Such plane mirrors reflect parallel incident light beams while keeping them parallel on the reflecting surface. For example, a lens with an optical mechanism for making light uniform (for example, a Fresnel lens) on which a reflective material is vapor-deposited can be used as a plane mirror. In this way, using plane mirrors as the reflecting mirrors M1 to M19 makes it possible to reduce manufacturing costs.

[0041] 2 illustrates, as a comparative example, a light collection region MR11 through which reflected light from the reflecting mirror M1 travels, a focal point P11 (the vertex of the approximately triangular shape corresponding to the light collection region MR11) corresponding to the light collection region MR11, and two sides L11 and L12. As described above, when a plane mirror with a flat reflecting surface is used as the reflecting mirror M1, the radius of curvature of the reflecting mirror M1 (corresponding to the two sides L11 and L12) is infinite. In this case, the radius of curvature of the light collection section 100 (corresponding to the directrix L1 and L2) is smaller than the radius of curvature of the reflecting mirror M1 (corresponding to the two sides L11 and L12).

[0042] In this way, it is possible to use, as the plurality of reflecting mirrors M1 to M19, reflecting mirrors having a flat shape or a curved shape with a radius of curvature (L11, L12) larger than the radius of curvature (L1, L2) of the light collecting part 100.

[0043] Furthermore, in the present embodiment, an example of the concentrating unit 100 having a circular shape when viewed from above has been described, but the present invention is not limited to this. For example, the concentrating unit 100 may have a shape with a portion of a circle missing (e.g., a semicircular shape) when viewed from above. In this case, it is preferable to set the position of the semicircle based on the direction of the sun. For example, it is also possible to install the solar power generation system 10 on a vehicle such as a ship or an automobile. However, in the case of a vehicle, the installation space available for installing the solar power generation system 10 is often limited. Therefore, by using the concentrating unit 100 having a shape with a portion of a circle missing (e.g., a semicircular shape) when viewed from above, the solar power generation system 10 can be installed even in places with limited installation space.

[0044] [Configuration example and effects of this embodiment] The solar power generation systems 10, 10a are equipped with concentrating units 100, 100a each having a parabolic reflective surface 101 formed by adjacently arranging a plurality of reflecting mirrors M1 to M19, M1a to M16a that reflect sunlight, with a focus P1 of reflected light set above the reflective surface 101, and a solar cell 200 including a predetermined photoelectric conversion element and installed within a light-concentrating region MR1 defined by the concentrating units 100, 100a and closer to the reflective surface 101 than the focus P1. The solar cell 200 is a concentrating solar cell.

[0045] According to this configuration, the plurality of reflectors M1-M19 and M1a-M16a can be used to form the concentrating units 100 and 100a, each of which has a parabolic reflecting surface 101 and has a focal point P1 of reflected light above the reflecting surface 101. This allows the concentrating units 100 and 100a to adequately collect the sunlight. Using a lightweight resin-based material for the reflecting mirrors and reducing their size can simplify the installation of the concentrating unit 100 and reduce the installation cost of the solar power generation system 10. Furthermore, since the solar cell 200 can be installed within the light-concentrating region MR1 of the concentrating unit 100 and closer to the reflecting surface 101 than the focal point P1, it is possible to prevent the solar cell 200 from becoming too hot and ensure that the sunlight concentrated by the concentrating unit 100 is adequately supplied to the solar cell 200. Furthermore, since there is no need to cover the installation site of the solar power generation system 10 with a large number of flat-plate cells, there is no need to prepare a large number of solar cells 200, and there is no need to secure a large installation area for covering the large number of flat-plate cells. This makes it possible to reduce the manufacturing and installation costs of the solar cells 200. In other words, it is possible to reduce the manufacturing and installation costs of the solar power generation system 10. In this way, solar power generation can be performed efficiently in a small space.

[0046] The solar power generation systems 10, 10a further include support columns 150 that support the concentrating units 100, 100a and the solar cells 200. The support columns 150 are configured to vertically penetrate the concentrating units 100, 100a, with the solar cells 200 fixed to the upper ends of the support columns 150. The solar cells 200 are arranged such that the lower surfaces (incident surfaces 201) of the solar cells 200 face the reflecting surfaces 101 of the concentrating units 100, 100a.

[0047] With this configuration, the support columns 150 make it possible to position the solar cells 200 at appropriate positions within the light-concentrating region MR1. This makes it possible to increase the efficiency of power generation by the solar cells 200. Furthermore, because the light-concentrating sections 100, 100a and the solar cells 200 are supported by the support columns 150 fixed to the installation location, it is not necessary to lay out a large number of flat-plate cells. In other words, since there is no need to secure a large installation area to lay out a large number of flat-plate cells, it is possible to make effective use of the space at the installation location.

[0048] The horizontal diameter D2 of the solar cell 200 can be set to be smaller than the horizontal diameter D1 of the light concentrating portions 100, 100a.

[0049] This configuration allows the use of solar cells 200 with diameter D2 smaller than diameter D1 in the horizontal direction of light concentrating sections 100, 100a, so there is no need to lay out a large number of flat-plate cells. In other words, it is only necessary to prepare small-sized solar cells 200, which allows the manufacturing cost of solar cells 200 to be reduced.

[0050] The reflecting mirrors M1 to M5 may be flat or curved reflecting mirrors whose radii of curvature (L11, L12) are larger than the radii of curvature (L1, L2) of the light collecting part 100.

[0051] For example, by arranging adjacent reflectors that are flat or curved with radii of curvature (L11, L12) larger than the radii of curvature (L1, L2) of the light collecting unit 100 to form a light collecting unit 100 having a parabolic reflecting surface 101, it is possible to set the focus P1 of the reflected light above the reflecting surface 101. This makes it possible for the light collecting unit 100 to collect sufficient sunlight.

[0052] The reflecting mirrors M1 to M19 and M1a to M16a may be polygonal in shape when viewed from above, and the light collecting section 100 may be formed by connecting a plurality of reflecting mirrors M1 to M19 and M1a to M16a.

[0053] For example, as shown in Fig. 3, if the reflecting mirrors M1 to M19 are shaped like a hexagon in top view, it is possible to reduce the gaps that occur between adjacent reflecting mirrors when the reflecting mirrors M1 to M19 are arranged adjacently. Similarly, as shown in Fig. 5, if the reflecting mirrors M1a to M16a are shaped like a substantial triangle (or a substantial sector) in top view, it is possible to reduce the gaps that occur between adjacent reflecting mirrors when the reflecting mirrors M1a to M16a are arranged adjacently. Note that even if the reflecting mirrors M1 to M19 are shaped like a triangle or a square in top view, it is possible to reduce the gaps that occur between adjacent reflecting mirrors.

[0054] The reflecting mirrors M1 to M19 and M1a to M16a may be formed by laminating a transparent resin material and a reflective material that reflects light.

[0055] For example, by using reflectors M1-M19 and M1a-M16a in which a reflective material is vapor-deposited on a transparent resin material, it is possible to reflect incident sunlight with a high reflectance, thereby improving power generation efficiency.Furthermore, for example, by using a resin material, which is lighter than glass, as the material for reflectors M1-M19 and M1a-M16a, it is possible to facilitate the installation work of solar power generation system 10 and reduce installation costs.

[0056] The solar cell 200 may be a multi-junction solar cell containing at least one of indium, gallium, germanium, phosphorus, and arsenic. The solar cell 200 may also be a multi-junction solar cell containing at least one of indium gallium phosphide (InGaP), indium gallium phosphide arsenide (InGaAs), gallium arsenide (GaAs), and germanium (Ge).

[0057] According to this configuration, by making the solar cell 200 a compound-based multi-junction solar cell (multilayer structure), it is possible to widen the wavelength range of light that can be converted into electricity compared to silicon-based solar cells, and to increase the conversion efficiency.

[0058] Although the embodiments of the present invention have been described above, the above embodiments merely illustrate some of the application examples of the present invention, and it is not intended that the technical scope of the present invention be limited to the specific configurations of the above embodiments. [Explanation of symbols]

[0059] 10, 10a solar power generation system, 100, 100a light collecting unit, 150 support column, 200 solar cell, 300 controller, 310 supply destination, M1 to M19, M1a to M16a reflector

Claims

1. a light collecting unit having a parabolic reflecting surface formed by arranging a plurality of reflecting mirrors adjacent to each other to reflect sunlight, the focus of the reflected light being set above the reflecting surface; a solar cell including a predetermined photoelectric conversion element and disposed within a light-collecting area of ​​the light-collecting unit and closer to the reflecting surface than the focal point; The solar cell is a concentrator solar cell. Solar power generation system.

2. The solar power generation system according to claim 1, a support column for supporting the light concentrator and the solar cell; the support pillar is configured to penetrate the light concentrating unit in the vertical direction, and the solar cell is fixed to an upper end of the support pillar; The solar cell is disposed so that a lower surface of the solar cell faces the reflecting surface. Solar power generation system.

3. The solar power generation system according to claim 2, a diameter of the solar cell in the horizontal direction is smaller than a diameter of the light concentrating portion in the horizontal direction; Solar power generation system.

4. The solar power generation system according to claim 1, The reflecting mirror is a reflecting mirror having a planar shape or a curved shape with a radius of curvature larger than the radius of curvature of the light collecting portion. Solar power generation system.

5. The solar power generation system according to claim 1, The reflecting mirror has a polygonal shape when viewed from above, The light collecting unit is formed by connecting the plurality of reflecting mirrors. Solar power generation system.

6. The solar power generation system according to claim 1, The reflecting mirror is formed by laminating a transparent resin material and a reflective material that reflects light. Solar power generation system.

7. 7. The solar power generation system according to claim 1, The solar cell is a multi-junction solar cell containing at least one of indium, gallium, germanium, phosphorus, and arsenic. Solar power generation system.

8. 7. The solar power generation system according to claim 1, The solar cell is a multi-junction solar cell containing at least one of indium gallium phosphide (InGaP), indium gallium phosphide arsenide (InGaAs), gallium arsenide (GaAs), and germanium (Ge). Solar power generation system.

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