Photovoltaic power generation device

Abstract

In photovoltaic power generation devices that generate electricity using light that was previously wasted without being used for power generation, the amount of light that was wasted without being used for power generation is reduced. [Solution] A photovoltaic power generation device 2 that generates photovoltaic power using light generated by a light source device 1 equipped with a laser light source or a discharge lamp light source is configured such that the arrangement of the first photovoltaic power generation cell 4 in the photovoltaic power generation device 2 is such that the amount of light per unit area (maximum irradiance) at the light receiving part of the first photovoltaic power generation cell 4 when the amount of light of the irradiated light that is shone on the first photovoltaic power generation cell 4 is at its maximum does not exceed the maximum amount of light that can be used for power generation per unit area of ​​the first photovoltaic power generation cell 4 (maximum effective irradiance for power generation).

Description

[Technical Field]

[0001] The present invention relates to a photovoltaic power generation device, and more particularly to a photovoltaic power generation device comprising a photovoltaic power generation cell that generates light using light generated by a light source device equipped with a laser light source or a discharge lamp light source as the irradiation light. [Background technology]

[0002] In recent years, there has been growing interest in energy harvesting technologies, which involve harvesting (harvesting) minute amounts of energy from the surrounding environment for use, and in particular, in energy harvesting technologies that generate electricity using energy from the surrounding environment. As an application of energy harvesting technology, rather than using weak light such as sunlight or indoor light for photoelectric power generation, proposals have been made in Patent Documents 1 to 5 to utilize light that would normally be wasted by irradiating photoelectric power generation devices such as solar cells with light source devices that generate strong light such as laser light or discharge lamp light, thereby generating electricity. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] International Publication No. 2014 / 019814 [Patent Document 2] U.S. Patent No. 7,460,981 [Patent Document 3] U.S. Patent No. 4,642,413 [Patent Document 4] Japanese Patent Publication No. 2006-310024 [Patent Document 5] Japanese Patent Application Publication No. 57-89283 [Non-patent literature]

[0004] [Non-Patent Document 1] Photonics for Photovoltaics: Advances and Opportunities, Erik C. Garnett, Bruno Ehrler, Albert Polman, and Esther Alarcon-Llado, https: / / pubs.acs.org / doi / 10.1021 / acsphotonics.0c01045 [Non-Patent Document 2] Solar panel orientation: How using East-West structures improves the performance of your project, Laura Rodriguez, 1 Jun, 21,https: / / ratedpower.com / blog / solar-panel-orientation / [Overview of the project] [Problems that the invention aims to solve]

[0005] A photovoltaic power generation device is equipped with a photovoltaic cell and generates electricity using light irradiated onto the photovoltaic cell. Each photovoltaic cell has a maximum possible power generation per unit area. This maximum power generation per unit area is not related to the irradiated light, but is determined by the type of photovoltaic cell, such as amorphous silicon, dye-sensitized, or others.

[0006] Once the type of photovoltaic cell and the wavelength distribution of the light illuminating the cell are determined, the photovoltaic efficiency when that type of photovoltaic cell is irradiated with light of that wavelength distribution is determined. Dividing the maximum possible power generation per unit area of ​​the photovoltaic cell by its photovoltaic efficiency gives the maximum amount of light that can be used for power generation per unit area when that type of photovoltaic cell is irradiated with light of that wavelength distribution.

[0007] If the amount of light per unit area on the irradiated surface (surface of the photovoltaic cell) of a photovoltaic cell exceeds the maximum amount of light that can be used for power generation per unit area of ​​the photovoltaic cell, the excess light will not be used for power generation and will ultimately be wasted as heat or other waste.

[0008] Laser light sources and discharge lamp light sources have rated output levels that take into account various conditions such as the stability and lifespan of the light source, and it is desirable to use them at the rated output level.

[0009] On the other hand, when these light sources are used, the light source output used by the equipment utilizing the light may be lower than the light source's rated output to prevent damage to the equipment. In such cases, while the output from the light source remains at its rated output, an external device, separate from both the light source and the equipment utilizing the light, may reduce the output used by the equipment utilizing the light from the light source compared to the light source's output. Such external devices include attenuators and mirrors with controlled transmittance.

[0010] If the output is reduced by an external device that is different from both the light source and the device that uses light from the light source, a difference will naturally occur where the actual output is lower than the rated output. This difference in output is absorbed or reflected by something called a damper, and ultimately it is converted into heat somewhere.

[0011] Patent documents 1-5 and others have proposed using the differential output to generate electricity by irradiating a photovoltaic cell without absorbing or reflecting it with a damper.

[0012] However, when a damper absorbs or reflects excess light from a light source device equipped with a laser light source or discharge lamp light source, the energy of the absorbed or reflected light is lost. On the other hand, if the excess light is irradiated directly onto the photovoltaic cell without being absorbed or reflected by a damper, the amount of light per unit area on the irradiated surface may exceed the maximum amount of light that can be used for power generation per unit area of ​​the power generation cell (hereinafter sometimes referred to as the maximum effective irradiance for power generation). In this case, there was a problem that the light exceeding the maximum effective irradiance for power generation was not used for power generation and was wasted as heat.

[0013] The present invention has been made in view of the above problems, and an object of the present invention is to provide a technique for reducing light that has conventionally been discarded without being used for power generation due to the limit of the maximum amount of light available for power generation per unit area of a photovoltaic cell, in a photovoltaic power generation apparatus that generates power by using excess light that has been conventionally discarded without being utilized, which is obtained from a light source device that generates intense light such as laser light or discharge lamp light. [Means for Solving the Problems]

[0014] In order to solve the above problems, one aspect of the present invention provides a photovoltaic power generation apparatus (2) that performs photovoltaic power generation by using light emitted from a light source device (1) including a laser light source or a discharge lamp light source as irradiation light, wherein the arrangement of a first photovoltaic cell (4) in the photovoltaic power generation apparatus is structured such that the light amount per unit area (hereinafter sometimes referred to as maximum irradiance) in a light receiving portion of the first photovoltaic cell when the light amount of irradiation light irradiated to the first photovoltaic cell is maximum does not exceed the maximum amount of light available for power generation per unit area (maximum effective power generation irradiance) of the first photovoltaic cell.

[0015] As shown in Fig. 7, in the arrangement of photovoltaic cells (4) in a conventional photovoltaic power generation apparatus (102), the photovoltaic cells (4) are arranged substantially perpendicular to irradiation light (3) emitted from the light source device (1), and light incident on the photovoltaic power generation apparatus (102) is directly irradiated onto the photovoltaic cells (4). Let the maximum value of the irradiation light (3) irradiated to the photovoltaic cell (4) be maximum irradiation light amount Imax, the area of the portion of the photovoltaic cell (4) that receives the irradiation light (3) be light receiving area S, and the maximum value of the light amount per unit area available for power generation by the photovoltaic cell (4) (hereinafter referred to as effective power generation irradiance) be maximum effective power generation irradiance Umax. The value obtained by multiplying the maximum effective power generation irradiance Umax by the light receiving area S (Umax×S) is the maximum power generation light amount of the photovoltaic cell (4). In the arrangement of the conventional photovoltaic power generation apparatus 102, when the maximum irradiation light amount Imax exceeds the maximum power generation light amount (Umax×S) of the photovoltaic cell 4, when the photovoltaic cell 4 is irradiated with the irradiation light 3 having the maximum irradiation light amount Imax, the light of Imax-Umax×S among the irradiation light 3 is discarded without being used for power generation.

[0016] In the photovoltaic power generation device according to the present invention, the photovoltaic power generation cells are arranged such that the actual light-receiving area S' of the portion of the first photovoltaic power generation cell that receives the irradiated light (hereinafter sometimes simply referred to as the photovoltaic power generation cell) does not fall below the value obtained by dividing the maximum irradiated light intensity Imax by the maximum effective irradiance for power generation Umax. With this configuration, even when the amount of irradiated light that hits the photovoltaic power generation cell is the maximum irradiated light intensity Imax, the amount of irradiated light that is wasted without being used for power generation is reduced.

[0017] Below, the maximum effective irradiance for power generation, Umax, is 0.015 W / cm². 2 Therefore, the light-receiving area S is 1 cm 2 Regarding conventional photovoltaic power generation devices equipped with photovoltaic cells, the maximum irradiation light intensity Imax is 0.03 W / cm². 2 Let's explain an example of this case.

[0018] In conventional photovoltaic power generation devices, the photovoltaic cell does not tilt relative to the irradiated light, resulting in a maximum irradiated light intensity Imax = 0.03 W and a maximum effective irradiance Umax = 0.015 W / cm². 2 , light receiving area S=1cm 2 Therefore, the maximum irradiated light intensity Imax = 0.03W, while the maximum generated light intensity (Umax × S) = 0.015W. Since Imax > Umax × S, there is a portion of the 0.03W of irradiated light that is not used for photovoltaic power generation, and that amount is Imax - Umax × S = 0.03 - 0.015 = 0.015 (W).

[0019] Next, an example will be described in which the tilt angle θ of the normal to the light-receiving surface of the photovoltaic cell with respect to the irradiated light is set to 65 degrees, according to the above embodiment of the present invention.

[0020] The maximum effective irradiance Umax of the photovoltaic cell is 0.015 W / cm². 2 The light-receiving area S of the photovoltaic cell is 1 cm 2 The maximum irradiation light intensity Imax is assumed to be 0.03W.

[0021] The photovoltaic cells are positioned at an inclination angle θ = 65 degrees with respect to the irradiated light, with a maximum irradiated light intensity Imax = 0.03 W and a maximum effective irradiance Umax = 0.015 W / cm².2 , light-receiving area S=1 cm 2 , when the inclination angle θ=65 degrees, cosθ=0.423. For the maximum irradiation light intensity Imax=0.03 W, the maximum generated power light intensity (Umax×S / cosθ)=0.0355 (W). Since Imax<Umax×S / cosθ, all 0.03 W of irradiation light is used for photovoltaic power generation. Imax(0.03 W)<Umax(0.015 W / cm 2 )×S(1 cm 2 ) / cosθ (65 degrees)=0.0355 (W), therefore all light with the maximum irradiation light intensity Imax=0.03 W is used for power generation without being discarded.

[0022] In the above aspect of the present invention, the photovoltaic power generation device further comprises a second photovoltaic cell (14) arranged at a position spaced apart from a photovoltaic cell (a first photovoltaic cell), part of the irradiation light irradiated onto the photovoltaic cell is reflected by the photovoltaic cell to become reflected irradiation light (13) irradiated onto the second photovoltaic cell, and the second photovoltaic cell is preferably arranged inclined relative to the reflected irradiation light.

[0023] Further, in the above aspect, the second inclination angle θ2 of the second photovoltaic cell relative to the reflected irradiation light is determined from the maximum irradiation light intensity Imax2 of the reflected irradiation light onto the second photovoltaic cell, the maximum power generation effective irradiance Umax2 of the second photovoltaic cell, and the light-receiving area S2 of the second photovoltaic cell, therefore the inclination angle θ of the first photovoltaic cell relative to irradiation light and the second inclination angle θ2 of the second photovoltaic cell relative to reflected irradiation light may be different from each other.

[0024] In a photovoltaic power generation device according to another aspect of the present invention, an irradiation light diffusing optical element is applied to irradiation light. Hereinafter, an example of the present invention in which an irradiation light diffusing optical element is applied and four photovoltaic cells are provided will be described. The optical characteristics and arrangement of the irradiation light diffusing optical element are selected so as to satisfy the following.

[0025] The maximum power generation effective irradiance Umax of the photovoltaic cell is 0.015 W / cm 2 , the light-receiving area S of the photovoltaic cell is 1 cm 2Four photovoltaic cells are arranged in a row, and the light is diffused by light-diffusing optical elements (5, 15) and irradiated onto the four photovoltaic cells. The light-diffusing optical elements can include convex lenses, concave lenses, convex mirrors, concave mirrors, diffusers, or combinations thereof. Beam shaping may also be used to adjust the light to match the arrangement of the photovoltaic cells.

[0026] The maximum effective irradiance Umax of the photovoltaic cell is 0.015 W / cm². 2 The light-receiving area S of the photovoltaic cell is 1 cm 2 Assume the maximum irradiation light intensity Imax is 0.03W. The number of photovoltaic cells M that receive the irradiation light diffused by the irradiation light diffusion optical element is 4. Maximum irradiation light intensity Imax = 0.03W, maximum effective irradiance Umax = 0.015W / cm² 2 , light receiving area S=1cm 2 Therefore, the maximum irradiated light intensity Imax = 0.03W, while the maximum generated light intensity (Umax × S × M) = 0.015 (W / cm²). 2 ) × 1 (cm 2 ) × 4 (sheets) = 0.06 (W). Imax (0.03W) <Umax(0.015W / cm 2 ) × S (1cm 2 Since ) × M(4 sheets) = 0.06(W), all of the light from the maximum illumination intensity Imax = 0.03W is used for photovoltaic power generation without being wasted.

[0027] In the above embodiment of the present invention, the light-diffusing optical element (5) may transmit and diffuse the light. Alternatively, the light-diffusing optical element (15) may reflect and diffuse the light. [Effects of the Invention]

[0028] As described above, according to the photovoltaic power generation device of the present invention, even when the amount of light irradiated onto the photovoltaic power generation cell is at its maximum irradiation intensity, the irradiated light is not wasted and is utilized for photovoltaic power generation. [Brief explanation of the drawing]

[0029] [Figure 1]This is a diagram showing the configuration of a photovoltaic power generation unit equipped with a photovoltaic power generation device according to a first embodiment of the present invention. [Figure 2] This is a diagram showing the configuration of a photovoltaic power generation unit equipped with a photovoltaic power generation device according to a second embodiment of the present invention. [Figure 3] This is a diagram showing the configuration of a photovoltaic power generation unit equipped with a photovoltaic power generation device according to the third embodiment of the present invention. [Figure 4] This is a diagram showing the configuration of a photovoltaic power generation unit equipped with a photovoltaic power generation device according to the fourth embodiment of the present invention. [Figure 5] This is a diagram showing the configuration of a photovoltaic power generation unit equipped with a photovoltaic power generation device according to the fifth embodiment of the present invention. [Figure 6] This is a diagram showing the configuration of a photovoltaic power generation unit equipped with a photovoltaic power generation device according to the sixth embodiment of the present invention. [Figure 7] This is a diagram illustrating the configuration of a photovoltaic power generation unit equipped with a conventional photovoltaic device. [Modes for carrying out the invention]

[0030] First, a conventional photovoltaic unit 110 will be described. Figure 7 shows the configuration of a conventional photovoltaic unit 110. The irradiation light 3 that is irradiated onto the photovoltaic cell 4 (first photovoltaic cell 4) is emitted from a light source device 1 equipped with a laser light source or a discharge lamp light source, enters the photovoltaic device 102, and then irradiates the photovoltaic cell 4. The maximum amount of light in the irradiation light 3 that irradiates the photovoltaic cell 4 is the maximum irradiation light amount Imax, the area of ​​the part of the photovoltaic cell 4 that receives the irradiation light 3 (i.e., the light receiving part) is the light receiving area S, and the maximum amount of light that can be used for power generation per unit area of ​​the photovoltaic cell 4 is the maximum effective irradiance for power generation Umax. If Imax > Umax × S, then when the amount of irradiation light 3 irradiated onto the photovoltaic cell 4 is the maximum irradiation light amount Imax, the amount of irradiation light 3 of Imax - Umax × S is wasted without being used for power generation.

[0031] Figure 1 shows the configuration of a photovoltaic unit 10 according to a first embodiment of the present invention. A light source device 1 includes a light source 1a consisting of a laser light source or a discharge lamp light source. Part of the light generated by the light source 1a exits the light source device 1 and enters the photovoltaic device 2, then becomes irradiation light 3 and irradiates the photovoltaic cell 4. The photovoltaic cell 4 is arranged at a predetermined inclination angle θ with respect to the irradiation light 3 (that is, such that the normal line 6 of the light-receiving surface of the photovoltaic cell 4 forms the inclination angle θ with respect to the irradiation light 3). Let Imax be the maximum value of the light quantity of the irradiation light 3 irradiating the photovoltaic cell 4, S be the light-receiving area which is the area of the light-receiving portion of the photovoltaic cell 4 that receives the irradiation light 3 as viewed from the irradiation light direction, and S' be the light-receiving area which is the actual area of the light-receiving portion of the photovoltaic cell 4 that receives the irradiation light 3 (the area viewed from the direction perpendicular to the surface). The inclination angle θ is set so as to satisfy Imax < Umax×S' = Umax×S / cosθ. With this arrangement, even when the light quantity of the irradiation light 3 irradiated to the photovoltaic cell 4 is the maximum irradiation light quantity Imax, the maximum irradiation light quantity Imax does not exceed Umax×S' = Umax×S / cosθ. In other words, even when the light quantity of the irradiation light 3 applied to the photovoltaic cell 4 is the maximum irradiation light quantity Imax, all of the irradiation light quantity applied to the photovoltaic cell 4 is used for power generation without being discarded. Note that when the photovoltaic cells 4 are connected in series, it is also possible to connect a bypass diode in parallel with each photovoltaic cell 4 in order to prevent the unirradiated photovoltaic cells 4 from consuming power instead of generating power.

[0032] FIG. 2 shows the configuration of a photovoltaic unit 10 according to a second embodiment of the present invention. Irradiation light 3 irradiated onto a photovoltaic cell 4 is emitted from a light source device 1, enters a photovoltaic device 2, and then irradiates the photovoltaic cell 4 (first photovoltaic cell 4). The photovoltaic cell 4 is arranged with an inclination angle θ with respect to the irradiation light 3. When the photovoltaic cell 4 is arranged without being inclined with respect to the irradiation light 3, the area of the portion of the photovoltaic cell 4 that receives the irradiation light 3 is defined as a light-receiving area S. When the photovoltaic cell 4 is arranged such that a light-receiving surface normal line 6 of the photovoltaic cell 4 forms the inclination angle θ with respect to the irradiation light 3, a light-receiving area S', which is the area of the portion of the photovoltaic cell 4 that receives the irradiation light 3, is S / cosθ. The inclination angle θ is set so as to satisfy Imax < Umax × S / cosθ. With this arrangement, even when the light amount of the irradiation light 3 irradiated onto the photovoltaic cell 4 is the maximum irradiation light amount Imax, Imax < Umax × S / cosθ holds. That is, even when the light amount of the irradiation light 3 on the photovoltaic cell 4 is the maximum irradiation light amount Imax, all of the irradiation light 3 on the photovoltaic cell 4 is used for power generation without being discarded. Furthermore, a second photovoltaic cell 14 that receives the irradiation light 3 reflected by the surface of the photovoltaic cell 4 (hereinafter referred to as reflected irradiation light 13) is similarly arranged such that a light-receiving surface normal line 16 thereof forms a second inclination angle θ2 with respect to the reflected irradiation light 13, and the reflected irradiation light 13 reflected by the surface of the photovoltaic cell 4 is also used for power generation by the second photovoltaic cell 14. The second inclination angle θ2 of the second photovoltaic cell 14 with respect to the reflected irradiation light 13 and the inclination angle θ of the first photovoltaic cell 4 with respect to the irradiation light 3 may be different from each other. An additional photovoltaic cell 4 may be similarly added behind the second photovoltaic cell 14. Note that when the photovoltaic cells 4 and 14 are connected in series, it is also possible to connect a bypass diode in parallel with each of the photovoltaic cells 4 and 14 in order to prevent the unilluminated photovoltaic cells 4 and 14 from consuming power.

[0033] Figure 3 shows the configuration of a photovoltaic unit 10 according to a third embodiment of the present invention. Irradiation light 3 that irradiates photovoltaic cells 4 exits a light source device 1 and enters a photovoltaic device 2, and then irradiates the photovoltaic cell 4 (the first photovoltaic cell 4), a second photovoltaic cell 14, a third photovoltaic cell 24, and a fourth photovoltaic cell 34. The photovoltaic cell 4, the second photovoltaic cell 14, the third photovoltaic cell 24, and the fourth photovoltaic cell 34 are arranged such that their respective light-receiving surface normals 6, ... form an inclination angle θ with respect to the irradiation light 3. The inclination angle θ is set to satisfy I_max < U_max × S / cosθ, where I_max is the maximum value of the light intensity of the irradiation light 3 that irradiates the photovoltaic cell 4, and S is the area of the portion of the photovoltaic cell 4 that receives the irradiation light 3 when viewed from the irradiation light direction. With this arrangement, even when the light intensity of the irradiation light 3 that irradiates the photovoltaic cell 4 is the maximum irradiation light intensity I_max, I_max < U_max × S / cosθ holds. That is, even when the light intensity of the irradiation light 3 incident on the photovoltaic cell 4 is the maximum irradiation light intensity I_max, all of the irradiation light 3 incident on the photovoltaic cell 4 is used for power generation without being discarded. Additional photovoltaic cells 4 may be further arranged in a manner repeating the arrangement of the photovoltaic cell 4, the second photovoltaic cell 14, the third photovoltaic cell 24, and the fourth photovoltaic cell 34. When the photovoltaic cells 4, 14, 24, and 34 are connected in series, it is also possible to connect a bypass diode in parallel with each of the photovoltaic cells 4, 14, 24, and 34 to prevent the unirradiated photovoltaic cells 4, 14, 24, and 34 from consuming power.

[0034] Note that mountain-shaped structures similar to those of the third embodiment of the present invention are disclosed in Non-Patent Documents 1 and 2. However, the mountain-shaped structure in Non-Patent Document 1 is for improving power generation efficiency by forming a mountain-shaped texture on the cell surface of a solar cell to increase light confinement inside the solar cell. And Non-Patent Document 1 does not provide any suggestion of considering the maximum effective power generation irradiance Umax of the photovoltaic cell 4 in the present invention.

[0035] The chevron-shaped structure described in Non-Patent Document 2 is proposed as a structure in which solar cell panels are arranged in a chevron shape. This is intended to avoid the occurrence of periods during which power cannot be generated when the sun's direction changes over time, when a plurality of solar cell panels are arranged outdoors and the orientation of the solar cell panels is fixed in one direction. And Non-Patent Document 2 provides no suggestion whatsoever of considering the maximum power generation effective irradiance Umax of the photovoltaic cell 4 in the present invention.

[0036] Fig. 4 shows the configuration of a photovoltaic unit 10 according to a fourth embodiment of the present invention. Irradiation light 3 irradiated onto the photovoltaic cell 4 exits from a light source device 1, enters the photovoltaic power generation device 2, and then irradiates the photovoltaic cell 4 through an irradiation light diffusing optical element 5. A convex lens, a concave lens, a convex mirror, a concave mirror, a diffusion plate, a beam expander, or a combination thereof can be used for the irradiation light diffusing optical element 5. Beam shaping may be used in combination to match the irradiation light 3 irradiated onto the photovoltaic cell 4 to the arrangement of the photovoltaic cell 4. Let the area of the light-receiving portion of the photovoltaic cell 4 when the photovoltaic cell 4 receives light without passing through the irradiation light diffusing optical element 5 be a light-receiving area S. Further, when the photovoltaic cell 4 receives light through the irradiation light diffusing optical element 5, let the area of the portion of the photovoltaic cell 4 that receives the irradiation light 3 be a light-receiving area S', let the maximum value of the light amount of the irradiation light 3 that irradiates the photovoltaic cell 4 be a maximum irradiation light amount Imax, and let the maximum value of the amount of light available for power generation per unit area of the photovoltaic cell 4 be a maximum power generation effective irradiance Umax. The irradiation light diffusing optical element 5 has its optical characteristics and position selected so as to satisfy Umax×S<Imax<Umax×S'.

[0037] Through this selection, all of the irradiation light 3 with the maximum irradiation light intensity Imax is utilized for photovoltaic power generation. That is, when the photovoltaic cell 4 receives light without passing through the irradiation light diffusion optical element 5, Umax×S<Imax holds, and there occurs a portion of the maximum irradiation light intensity Imax that is not utilized for photovoltaic power generation. In contrast, when the photovoltaic cell 4 receives light through the irradiation light diffusion optical element 5, Imax<Umax×S' holds, and all of the maximum irradiation light intensity Imax is utilized for photovoltaic power generation. That is, the photovoltaic cells 4 are arranged such that the light intensity per unit area (maximum irradiance) at the light-receiving portion of the photovoltaic cell 4 when the light intensity of the irradiation light 3 irradiated onto the photovoltaic cell 4 is maximum does not exceed the maximum utilizable light intensity per unit area for power generation (maximum effective power generation irradiance Umax) of the photovoltaic cell 4. In addition, when the photovoltaic cells 4 are connected in series, it is also possible to connect a bypass diode in parallel with each photovoltaic cell 4 to avoid power consumption by the photovoltaic cells 4 that are not irradiated with light.

[0038] FIG. 5 shows a configuration of a photovoltaic unit 10 according to a fifth embodiment of the present invention. Irradiation light 3 irradiated onto a photovoltaic cell 4 exits a light source device 1, enters a photovoltaic device 2, then passes through an irradiation light diffusion optical element 5, and irradiates the photovoltaic cell 4, a second photovoltaic cell 14, and a third photovoltaic cell 24. A convex lens, a concave lens, a convex mirror, a concave mirror, a diffusion plate, a beam expander, or a combination of these can be used for the irradiation light diffusion optical element 5. When the irradiation light diffusion optical element 5 is not disposed, let the area of a portion where the photovoltaic cell 4 receives the irradiation light 3 be a light-receiving area S, and when the irradiation light diffusion optical element 5 is disposed, let the total area of portions where the photovoltaic cell 4, the second photovoltaic cell 14 and the third photovoltaic cell 24 receive the irradiation light 3 be a light-receiving area S'. Optical characteristics and a position of the irradiation light diffusion optical element 5 are selected so as to satisfy Umax×S<Imax<Umax×S'. By this selection, when a light amount of the irradiation light 3 with which the photovoltaic cell 4 is irradiated is a maximum irradiation light amount Imax, and when the irradiation light diffusion optical element 5 is not disposed, Umax×S<Imax is satisfied. That is, there occurs a portion of the maximum irradiation light amount Imax that is not used for photovoltaic power generation. In contrast, when the irradiation light diffusion optical element 5 is disposed, Imax<Umax×S' is satisfied. That is, all of the irradiation light 3 of the maximum irradiation light amount Imax is used for photovoltaic power generation. In the fifth embodiment of the present invention, a plurality of photovoltaic cells 4, 14, 24, 34, ... are sequentially arranged inside a spherical surface like the photovoltaic cell 4, the second photovoltaic cell 14, and the third photovoltaic cell 24. Therefore, light reflected on the surface of each of the photovoltaic cells 4, 14, 24 also re-enters another photovoltaic cell 34, ... and is used for power generation. Additional photovoltaic cells 4 may be further disposed so as to cover the inside of the spherical surface. Note that when connecting the photovoltaic cells 4, 14, 24 in series, it is also possible to connect a bypass diode in parallel with each of the photovoltaic cells 4, 14, 24 in order to avoid power consumption by the photovoltaic cells 4, 14, 24 that are not irradiated with light.

[0039] FIG. 6 shows a configuration of a photovoltaic power generation unit 10 according to a sixth embodiment of the present invention. Irradiation light 3 that irradiates photovoltaic power generation cells 4 exits a light source device 1, enters a photovoltaic power generation device 2, is weakly diffused by a first irradiation light diffusion optical element 5, and then is diffused in a reflection direction by a second irradiation light diffusion optical element 15 to irradiate the photovoltaic power generation cell 4 and a second photovoltaic power generation cell 14. A convex lens, a concave lens, a convex mirror, a concave mirror, a diffusion plate, a beam expander, or a combination of these can be used for the irradiation light diffusion optical element 5 and the second irradiation light diffusion optical element 15. Let the area of a portion of the photovoltaic power generation cell 4 that receives the irradiation light 3 when the irradiation light diffusion optical element 5 and the second irradiation light diffusion optical element 15 are not disposed be a light receiving area S. When the irradiation light diffusion optical element 5 and the second irradiation light diffusion optical element 15 are disposed, let the total area of the portion of the photovoltaic power generation cell 4 that receives the irradiation light 3 reflected by the second irradiation light diffusion optical element 15 and the portion of the second photovoltaic power generation cell 14 be a light receiving area S'. The optical characteristics and arrangement of the irradiation light diffusion optical element 5 and the second irradiation light diffusion optical element 15 are selected so as to satisfy Umax×S<Imax<Umax×S'. With this arrangement, even when the light amount of the irradiation light 3 irradiating the photovoltaic power generation cell 4 is the maximum irradiation light amount Imax, Imax<Umax×S' holds. That is, even when the light amount of the irradiation light 3 to the photovoltaic power generation cell 4 is the maximum irradiation light amount Imax, all of the irradiation light 3 to the photovoltaic power generation cell 4 is used for power generation without being discarded. In the sixth embodiment of the present invention, since the photovoltaic power generation cell 4 is disposed inside a spherical surface, a third photovoltaic power generation cell 24 that receives reflected irradiation light 13 reflected by the photovoltaic power generation cell 4, and a fourth photovoltaic power generation cell 34 that receives reflected irradiation light 13 reflected by the second photovoltaic power generation cell 14 may be additionally disposed. Note that when the photovoltaic power generation cells 4, 14, 24 are connected in series, it is also possible to connect a bypass diode in parallel with each of the photovoltaic power generation cells 4, 14, 24 in order to prevent the non-irradiated photovoltaic power generation cells 4, 14, 24 from consuming power.

[0040] When the photovoltaic power generation device 2 of the present invention is used instead of a damper, while light incident on a damper is converted into heat, light incident on the photovoltaic power generation device 2 of the present invention is used for power generation, which also has the effect of reducing the amount of heat generated.

[0041] Although the present invention has been described above in terms of preferred embodiments, the present invention is not limited to these embodiments and can be modified as appropriate without departing from the spirit of the invention. For example, some or all of the above embodiment configurations may be combined and implemented. Furthermore, not all of the components shown in the above embodiments are necessarily essential, and they can be selected and omitted as appropriate without departing from the spirit of the invention. [Explanation of Symbols]

[0042] 1:Light source device 1a: light source 2: Photovoltaic power generation device 3: Irradiated light 4: Photovoltaic cell (first photovoltaic cell) 5: Irradiation light diffusion optical element 6: Normal vector of the light-receiving surface of a photovoltaic cell 10: Photovoltaic power generation unit 13:Reflected irradiation light 14: Second photovoltaic cell 15: Second Irradiation Light Diffusing Optical Element 16: Normal vector of the light-receiving surface of the second photovoltaic cell 24: Third photovoltaic cell 34: The fourth photovoltaic cell 102: Photovoltaic power generation device 110: Photovoltaic power generation unit Imax: Maximum irradiation amount Imax2: Maximum light intensity of reflected light irradiated onto the second photovoltaic cell. M: Number of photovoltaic cells S: Light receiving area S2: Light-receiving area of ​​the second photovoltaic cell S': Light receiving area Umax: Maximum effective irradiance for power generation Umax2: Maximum effective irradiance for power generation of the second photovoltaic cell θ: Inclination angle θ2: Second tilt angle of the second photovoltaic cell

Claims

1. A photovoltaic power generation device comprising a first photovoltaic cell that generates photovoltaic power using light generated by a light source device equipped with a laser light source or a discharge lamp light source, The first photovoltaic cell is positioned at a predetermined angle of inclination with respect to the irradiated light, When the amount of light irradiated onto the first photovoltaic cell is at its maximum, the amount of light per unit area at the light receiving section of the first photovoltaic cell is defined as the maximum irradiance, and the maximum value of the amount of light per unit area that the first photovoltaic cell can use for power generation is defined as the maximum effective irradiance for power generation. When the first photovoltaic cell is positioned without tilting with respect to the irradiated light, the maximum irradiance exceeds the maximum effective irradiance for power generation. A photovoltaic power generation device in which, when the first photovoltaic power generation cell is positioned at an angle with respect to the irradiated light, the tilt angle of the first photovoltaic power generation cell is set so that the maximum irradiance does not exceed the maximum effective irradiance for power generation.

2. The system further comprises a second photoelectric cell positioned at a distance from the first photoelectric cell, wherein a portion of the light irradiated onto the first photoelectric cell is reflected by the first photoelectric cell and becomes reflected light irradiated onto the second photoelectric cell. The photovoltaic power generation device according to claim 1, wherein the second photovoltaic power generation cell is arranged at an angle with respect to the reflected light.

3. The photovoltaic device according to claim 2, wherein the inclination angle of the first photovoltaic cell with respect to the irradiated light and the inclination angle of the second photovoltaic cell with respect to the reflected irradiated light are different from each other.

4. A photoelectric power generation cell that generates electricity using light emitted from a light source device equipped with a laser light source or a discharge lamp light source, A photovoltaic power generation device comprising an illuminated light diffusing optical element disposed in the optical path between the light source device and the photovoltaic power generation cell, When the amount of light irradiated onto the photovoltaic cell is at its maximum, the amount of light per unit area at the light receiving section of the photovoltaic cell is defined as the maximum irradiance, and the maximum value of the amount of light per unit area that the photovoltaic cell can use for power generation is defined as the maximum effective irradiance for power generation. If the aforementioned light-diffusing optical element is not provided, the maximum irradiance will exceed the maximum effective irradiance for power generation. A photovoltaic power generation device in which, when the aforementioned light-diffusing optical element is arranged, the optical characteristics and position of the light-diffusing optical element are set so that the maximum irradiance does not exceed the maximum effective irradiance for power generation.

5. The photovoltaic power generation device according to claim 4, wherein the light-diffusing optical element transmits and diffuses the light.

6. The photovoltaic power generation device according to claim 4, wherein the light-diffusing optical element reflects and diffuses the light.

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