Light condensation type photovoltaic generation device

Description: TECHNICAL FIELD [Detailed description of the invention]

【0001】

[Technical field to which the invention belongs]

The present invention relates to an improvement of a concentrating photovoltaic power generation device that converts the light energy of condensed sunlight into electrical energy by a condensing solar cell.

【0002】

[Conventional technology]

A concentrating photovoltaic power generation device that converts the light energy of condensed sunlight into electrical energy by a condensing solar cell is known. In such a condensing photovoltaic power generation device, instead of laying solar cells on one surface irradiated with sunlight, the sunlight incident on that surface is condensing using a primary optical system such as a condensing mirror or a condensing lens. Photovoltaic power is generated by irradiating the light receiving surface of the solar cell with light, and the cost of the material of the solar cell is replaced by the cost of the condenser, support, tracking device, etc. It is expected that the cost of the type photovoltaic power generation device as a whole will be reduced.

【0003】

In general, a photovoltaic power generation device provided with a solar cell using a compound semiconductor takes the form of a condensing type photovoltaic power generation device in order to reduce costs and improve efficiency. Condensing solar cells using compound semiconductors have less reduction in conversion efficiency due to temperature rise due to condensing than condensing solar cells using silicon-based semiconductors, and can perform about 1000 times higher condensing operation. Will be done. Regarding a condensing solar cell using such a compound semiconductor, development is underway for practical use of a multi-junction cell having a junction portion having a plurality of types of absorption wavelength bands having different center wavelengths in the thickness direction. .. Single junction cells with junctions with a single absorption wavelength band are limited to conversion efficiencies of 26-28%, while multijunction cells are expected to have conversion efficiencies in excess of 30%. As an example of a condensing photovoltaic power generation device equipped with a multi-junction cell, the length of the path through which the direct solar light incident perpendicularly to the atmosphere in the standard state is AM1 is equipped with a GaAs heteroface cell. Varian has reported a condensing photovoltaic power generation device that achieves an efficiency of 29.2% by condensing 205 times with a magnification of 1.5.

【0004】

As a configuration example of the concentrating photovoltaic power generation device, a case having one end open and a primary optical system fitted in the opening of the case are provided, and a metal foil is fixed to the lower surface of the semiconductor main body. There is known a concentrating photovoltaic power generation device in which an optical solar cell is fixed to a seat plate (base plate) provided in the case. In the concentrating photovoltaic power generation device configured in this way, the sunlight focused by the non-imaging Frenel lens, which is the primary optical system, is emitted onto the light receiving surface of the condensing solar cell. The concentrating solar cell converts the light energy of sunlight into electrical energy and outputs electric power.

【0005】

In the above-mentioned concentrating photovoltaic cell, the condensing solar cell is inevitably heated by condensing, and as a result, the conversion efficiency of the condensing solar cell that is excessively heated is 10%. Various coolers have been developed that maintain the concentrating solar cell in a suitable temperature range in order to solve the problem that the degree of decrease is also caused. For example, a water-cooled pipe described in JP-A-59-40589, a heat-dissipating fin described in JP-A-11-284217, or a heat sink (heat sink) disclosed in US Pat. No. 5,498,297. And so on.

【0006】

[Problems to be Solved by the Invention]

However, while the above-mentioned conventional techniques have the effect of maintaining the concentrating solar cell in a suitable temperature range, they are not suitable for practical use because they all have a complicated structure or an excessive weight. .. In addition to parallel light that reaches parallel to the incident direction, sunlight contains diffused light of about 15% in fine weather and about 80% in cloudy weather, and such diffused light is a condensing solar cell. By irradiating the seat plate without condensing the light on the light receiving surface of the above, the temperature of the seat plate is raised, which causes a decrease in heat dissipation performance. Further, when the tracking of the tracking device is slightly deviated, the same problem occurs.

【0007】

The present invention has been made against the background of the above circumstances, and an object of the present invention is to provide a concentrating photovoltaic power generation device that maintains a condensing solar cell in a suitable temperature range by a simple structure. To provide.

【0008】

[Means for solving problems]

In order to achieve the above object, the gist of the present invention is a condensing solar cell, a seat plate for fixing the condensing solar cell, and the condensing solar cell. It is a condensing photovoltaic power generation device provided with a primary optical system for condensing sunlight on a light receiving surface, and the seat plate is an upper surface on which the condensing solar cell is fixed and a top surface thereof. The lower surface is parallel to the upper surface, and different surface treatments are applied to the lower surface.

【0009】

[Effect of the invention]

In this way, the upper surface thereof is subjected to surface treatment for suppressing the temperature rise of the seat plate due to diffused light, and the lower surface parallel to the upper surface thereof is subjected to surface treatment for efficient heat dissipation. With a simple structure such as using a seat plate, it is possible to provide a concentrating photovoltaic power generation device that maintains the condensing solar cell in a suitable temperature range.

【0010】

[Other Aspects of the Invention]

Here, the seat plate is preferably one whose upper surface is mirror-treated. In this way, the diffused light contained in the sunlight is reflected by the upper surface of the mirror-treated seat plate, so that the temperature rise of the seat plate can be efficiently suppressed.

【0011】

Further, the seat plate is preferably one whose lower surface is colored. In this way, efficient heat dissipation can be performed by heat radiation from the lower surface of the colored seat plate, and as a result, the temperature of the condensing solar cell can be suitably maintained. ..

【0012】

Further, the seat plate preferably has a light-shielding plate that is thermally insulated from the seat plate at a position on the upper surface side thereof that does not block sunlight toward the light receiving surface of the condensing solar cell. It is provided. Here, thermal insulation does not mean complete insulation, but means that the thermal interference between the seat plate and the light-shielding plate is substantially negligible. In this way, the diffused light contained in the sunlight is blocked or reflected by the light-shielding plate that is thermally insulated from the seat plate, so that the temperature rise of the seat plate can be efficiently suppressed.

【0013】

[Example]

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. It should be noted that the dimensional ratios and the like of each part are not always drawn accurately with respect to the drawings used in the following description.

【0014】

FIG. 1 is a perspective view of a solar tracking device 12 in which the concentrating photovoltaic power generation device 10 according to an embodiment of the present invention is used. The photovoltaic tracking device 12 shown in FIG. 1 enables the concentrating photovoltaic power generation device 10 of the embodiment of the present invention and the concentrating photovoltaic power generation device 10 to be rotatable around the vertical axis and the horizontal axis. A vertical axis that supports and rotationally drives the concentrating photovoltaic device 10 around the vertical axis and the horizontal axis so that the concentrating photovoltaic device 10 is maintained in a posture facing the sun. It has a drive device 14, a horizontal axis drive device 16, and a sun position sensor 18 fixed to one side surface of the concentrating photovoltaic power generation device 10, and tracks the position of the sun so that it can always face the sun. It is designed to do. The vertical axis drive device 14 is fixed to a vertical axis 20 that can rotate around the vertical axis that protrudes upward, and the vertical axis 20 that rotatably supports the concentrating photovoltaic power generation device 10 around the horizontal axis. It is equipped with a U-shaped arm 22 for doing so. The horizontal axis drive device 16 is provided at one end of the U-shaped arm 22, and is directly or indirectly connected to the horizontal axis 24 supporting the concentrating photovoltaic power generation device 10 via a simple speed reducer. It has an output shaft (not shown).

【0015】

2A and 2B are views showing the configuration of the concentrating photovoltaic power generation device 10 of the present embodiment, in which FIG. 2A is a plan view and FIG. is there. As shown in this figure, the condensing type photovoltaic power generation device 10 is fitted into, for example, a case 26 formed of a plastic material or the like and having an opening at one end surface, and an opening of the case 26 in order to function as a primary optical system. On the attached non-imaging Fresnel lens 28, the seat plate 30 provided at the bottom of the case 26, and the bottom surface of the case 26, that is, the seat plate 30, which is the focusing position of the non-imaging Fresnel lens 28. It is equipped with an installed condensing solar cell 32 and a tubular reflector 34 that functions as a secondary optical system.

【0016】

In the concentrating photovoltaic power generation device 10 configured as described above, as shown by the two-point chain line in FIG. 2 (b), the sunlight condensing by the non-imaging Frenel lens 28 is reflected in a tubular shape. When the light receiving surface 40 of the condensing solar cell 32 passes through the mirror 34 and is irradiated, the condensing solar cell 32 generates photovoltaic power and outputs electric power. In this condensing type photovoltaic power generation device 10, since the non-imaging Fresnel lens 28 is used, the non-imaging Fresnel lens 28 collects light as long as it is within a predetermined angle range with respect to the direction toward the sun. The focused light intensity of the type solar cell 32 can be made constant.

【0017】

FIG. 3 is a structural diagram illustrating the structure of the concentrating solar cell 32. As shown in this figure, the condensing solar cell 32 used in this embodiment has, for example, a multi-junction structure in which a plurality of types of pn junctions having different absorption wavelength bands are laminated. The bottom junction layer 46, in which a pn junction is formed by forming the upper part of the type Ge substrate 44 into an n-type by diffusion of impurities, and n of about 0.1 μm.⁺-GaAs layer and n⁺-The buffer layer 48, which is sequentially composed of (In) GaAs layers and laminated on the Ge substrate, and n⁺⁺-InGaP layer and p⁺⁺-The first tunnel layer 50, which is sequentially composed of AlGaAs layers and laminated on the buffer layer 48, and p.⁺-InGaP layer, p- (In) GaAs layer, n⁺-(In) GaAs layer, n⁺-Intermediate junction layer 52, in which a pn junction is formed by being sequentially composed of AlInP layers, and n⁺⁺-InGaAs layer and p⁺⁺-The second tunnel layer 54, which is sequentially composed of AlGaAs layers and laminated on the intermediate junction layer 52, and the p-AlInP layer, p-InGaP layer, and n.⁺-InGaP layer, n⁺-It has an upper junction layer 56 in which a pn junction is formed by being sequentially composed of AlInP layers. Further, the lower electrode 58 is fixed to the lower surface of the condensing solar cell 32, and the upper electrode 42 is fixed to the upper surface except for the light receiving surface 40. N of the upper electrode 42 and the upper bonding layer 56⁺-With the AlInP layer, for example, n⁺A contact layer 60 made of-(In) GaAs is provided, and n of the upper bonding layer 56.⁺-An antireflection film 62 is provided on the exposed surface of the AlInP layer. The substances shown in [] in FIG. 3 are impurities diffused or ion-implanted in order to set the semiconductor type.

【0018】

The pn junctions provided in the bottom junction layer 46, the intermediate junction layer 52, and the upper junction layer 56 are electrically connected in series and have absorption wavelength bands having different center wavelengths. For example, blue light having a wavelength of 300 to 600 (nm) is bonded to the upper bonding layer 56, yellow light having a wavelength of 600 to 1000 (nm) is bonded to the middle bonding layer 52, and red light having a wavelength of 1000 to 1800 (nm) is bonded to the bottom. By absorbing each of the layers 46, high conversion efficiency can be obtained by setting the absorption wavelength band in the wavelength band of sunlight as a wide range.

【0019】

FIG. 4 is a perspective view showing the tubular reflector 34 used in the present embodiment, and FIG. 5 is a condensing solar cell in the condensing solar cell 10 in which the tubular reflector 34 is fixedly attached. FIG. 5 is a cross-sectional view showing the vicinity of the cell 32 cut along a plane substantially perpendicular to the light receiving surface 40 of the condensing solar cell 32. As shown in FIG. 4, the tubular reflector 34 used in this embodiment is a tubular hexahedron having two openings, an upper opening 34a forming a light receiving portion and a lower opening 34b forming a light emitting portion, and is a lower portion. A fixing allowance 34c for fixing to the seat plate 30 extends from one side of the opening 34b. The inner wall surface of the tubular reflector 34 is a mirror surface having a reflectance of about 95%. The tubular reflector 34 is fixed to the seat plate 30 by a fixing allowance 34c (not shown in FIG. 5).

【0020】

The tubular reflector 34 functions as a secondary optical system as described above. That is, a part of the sunlight collected by the non-imaging Fresnel lens 28, which is the primary optical system, is reflected by the inner wall surface of the tubular reflector 34, and the light receiving surface 40 of the condensing solar cell 32. The chromatic aberration caused by the primary optical system is corrected, and the conversion efficiency of the condensing solar cell 32 is improved. Further, even if the tracking of the solar tracking device 12 is slightly deviated, the focused sunlight can be irradiated to the light receiving surface 40 of the condensing solar cell 32, so that the condensed sunlight can be emitted. By irradiating the seat plate 30 with the light receiving surface 40 off, deterioration of the wiring or the like provided on the upper surface of the seat plate 30 is prevented.

【0021】

In the condensing type photovoltaic power generation device 10 of the present embodiment, the seat plate 30 is made of, for example, a metal containing aluminum as a main component (in the following description, this is referred to as an aluminum alloy) or the like, for example, about 3 (mm). The upper surface 30a, which is formed in a thick plate shape and on which the condensing solar cell 32 is fixed, and the lower surface 30b, which is parallel to the upper surface 30a, are subjected to different surface treatments. .. That is, the upper surface 30a is subjected to a mirror surface treatment such as forming a white alumite film of about 5 (μm) after buffing to obtain a mirror surface having a reflectance of about 91%, and the lower surface 30b thereof is formed. It is colored, for example, black, brown, or dark green by painting, coloring alumite treatment, laminating a colored resin, or coloring treatment such as black chrome plating.

【0022】

The seat plate 30 of this embodiment has a function not only as a base plate for fixing the condensing solar cell 32 but also as a radiator for maintaining the condensing solar cell 32 in a suitable temperature range. Therefore, the concentrating solar power generation device 10 of the present embodiment is not provided with a separate radiator such as a radiator fin or a heat sink. This is because by configuring the seat plate 30 as described above, it is possible to impart sufficient heat dissipation performance to the seat plate 30. That is, when the seat plate 30 is considered as a radiator, one of the factors that hinder the heat dissipation of the condensing solar cell 32 is that the diffused light contained in sunlight is the light receiving surface 40 of the condensing solar cell 32. The upper surface 30a of the seat plate 30 may be heated by irradiating the upper surface 30a of the seat plate 30 without condensing the light. However, as in this embodiment, the upper surface 30a of the seat plate 30 is a mirror surface. As shown in FIG. 5, most of the diffused light is reflected by the upper surface 30a of the seat plate 30 and radiated to the outside via the non-imaging Frenel lens 28. The temperature rise of the seat plate 30 due to the diffused light can be suitably suppressed. Further, by coloring the lower surface 30b of the seat plate 30 to a color having low brightness such as black, brown, or dark green as described above, heat is efficiently radiated from the lower surface 30b of the seat plate 30 by heat radiation. Combined with the effect obtained by the surface treatment of the upper surface 30a, the condensing solar cell 32 can be maintained in a suitable temperature range.

【0023】

In order to verify the effect of the present invention, the present inventors have applied a mirror finish treatment to the upper surface 30a and a black coating on the lower surface 30b as the seat plate 30 of the present embodiment to a thickness of 3 (mm). Example sample which is an aluminum alloy plate of the above, comparative example sample 1 which is an aluminum alloy plate of thickness 3 (mm) which is unprocessed on both sides as a seat plate 30 of the prior art, and thickness 0.8 which is unprocessed on both sides. Comparative Example sample 2 which is a (mm) SUS304 plate, and Comparative Example sample 3 which is an aluminum alloy plate having a thickness of 3 (mm) in which the upper surface 30a is mirror-finished and the lower surface 30b is unprocessed, and the upper surface. Comparative example sample 4, which is an aluminum alloy plate with a thickness of 3 (mm) in which 30a is unprocessed and the lower surface 30b is treated with black alumite, is prepared, and 10 (mm) × 48 (10 (mm) × 48 ( 24 silicon-based condensing solar cells equipped with a light receiving surface of mm) are fixed in series and used in a condensing solar power generation device equipped with a 20x condensing Frenel lens for power generation test. Was done. August 28: Automatically starts tracking from sunrise in Nagoya City (fine weather), tracks in one axis on the tracking axis parallel to the earth's axis, and at noon, the temperature (° C) of the solar cell and the open circuit voltage ( The results of measuring V) and conversion efficiency (%) are shown below.

【0024】

[Test results] Temperature (° C) Open circuit voltage (V) Conversion efficiency (%) Example sample 45 16.0 15.2 Comparative Example Sample 1 80 13.6 13.5 Comparative Example Sample 2 87 13.0 13.1 Comparative Example Sample 3 57 15.2 14.7 Comparative Example Sample 4 51 15.6 15.0 [0025]

According to the above test results, the concentrating photovoltaic power generation device 10 provided with the seat plate 30 of the present embodiment is based on the prior art with respect to all of the temperature, open circuit voltage, and conversion efficiency of the condensing solar cell 32. It can be seen that the results are superior to those of the concentrating photovoltaic power generation device equipped with a seat plate.

【0026】

As described above, according to the present embodiment, the upper surface 30a is subjected to surface treatment for suppressing the temperature rise of the seat plate 30 due to the diffused light, and the lower surface 30b parallel to the upper surface 30a is efficient. Provided is a condensing photovoltaic power generation device 10 that maintains the condensing solar cell 32 in a suitable temperature range by a simple structure such as using a seat plate 30 that has been surface-treated to dissipate heat. Can be done.

【0027】

Further, since the seat plate 30 of the present embodiment is preferably mirror-treated on the upper surface 30a, the diffused light contained in the sunlight is contained in the upper surface 30a of the mirror-treated seat plate 30. Is reflected, and the temperature rise of the seat plate 30 can be efficiently suppressed.

【0028】

Further, since the seat plate 30 of the present embodiment is preferably colored on the lower surface 30b thereof, efficient heat dissipation by heat radiation from the lower surface 30b of the colored seat plate 30 is performed. As a result, the temperature of the condensing solar cell 32 can be suitably maintained. Further, when the concentrating photovoltaic power generation device 10 is arranged in the wilderness or idle land, there is an advantage that the landscape of the surrounding vegetation is not spoiled.

【0029】

Next, the condensing type photovoltaic power generation device 70, which is another embodiment of the present invention, will be described. In the following description, the parts common to the above-described embodiment are designated by the same reference numerals and the description thereof will be omitted.

【0030】

FIG. 6 is a diagram showing a configuration of a concentrating photovoltaic power generation device 70 according to another embodiment of the present invention, in which (a) is a plan view and (b) is cut by a alternate long and short dash line (a). It is a schematic cross-sectional view which shows. As shown in this figure, the concentrating photovoltaic power generation device 70 is on the upper surface 30a side of the seat plate 30, that is, the side on which the condensing solar cell 32 is fixedly installed, and is the condensing solar cell. A light-shielding plate 74 is provided at a position that does not block sunlight toward the light-receiving surface 40 of 32, for example, by being thermally insulated from the seat plate 30 by a synthetic resin 72 having a low thermal conductivity. .. Here, thermal insulation does not mean complete insulation, for example, it is shown that the thermal interference between the seat plate 30 and the light-shielding plate 74 is so small that it can be substantially ignored, and also in the following description. It is used in the same meaning. Such a light-shielding plate 74 is, for example, one in which one side thereof is subjected to mirror surface treatment to be a mirror surface having a reflectance of about 91%, and the mirror surface side is installed so as to be the side to be irradiated with diffused light. ..

【0031】

FIG. 7 is a cross-sectional view showing the vicinity of the condensing solar cell 32 in the condensing photovoltaic cell 70, cut along a plane substantially perpendicular to the light receiving surface 40 of the condensing solar cell 32. .. In the condensing photovoltaic power generation device 70 of the present embodiment, the upper surface of the light-shielding plate 74 is a mirror surface, so that most of the diffused light is reflected by the upper surface of the light-shielding plate 74 as shown in FIG. It is radiated to the outside via the non-imaging Fresnel lens 28. Further, since the light-shielding plate 74 is thermally insulated from the seat plate 30 by the synthetic resin 72 and fixed, the temperature rise of the seat plate 30 can be more preferably suppressed, and as a result, the condensing type The solar cell 32 can be maintained in a suitable temperature range.

【0032】

As described above, the seat plate 30 of the present embodiment is thermally connected to the seat plate 30 at a position on the upper surface 30a side thereof so as not to block the sunlight toward the light receiving surface 40 of the concentrating solar cell 32. Since the light-shielding plate 74 is provided with an insulated light-shielding plate 74, the diffused light contained in the sunlight is reflected by the light-shielding plate 74, so that the temperature rise of the seat plate 30 can be efficiently suppressed.

【0033】

Subsequently, a condensing type photovoltaic power generation device 80, which is still another embodiment of the present invention, will be described.

【0034】

FIG. 8 is a perspective view of the solar tracking device 82 in which the concentrating photovoltaic power generation device 80, which is still another embodiment of the present invention, is used. As shown in FIG. 8, the solar tracking device 82 includes a plurality of (three in this embodiment) concentrating photovoltaic power generation device 80, which is a longitudinal line condensing photovoltaic power generation device, and the photovoltaic power generation device 80 thereof. An outer frame 84 that holds and fixes a plurality of concentrating photovoltaic power generation devices 80 at both ends, a sun position sensor 86 that is fixed to the outer frame 84 and detects the position of the sun, and the outer frame 84. It is rotatably supported around the vertical axis and the horizontal axis, and is rotationally driven around the vertical axis and the horizontal axis so that the concentrating photovoltaic power generation device 80 is always maintained in a posture facing the sun. It is configured with a tracking mechanism (not shown) and a support column 88 connected to the tracking mechanism, and by tracking the position of the sun so that it can always face the sun, efficient photovoltaic power generation can be performed. Is possible.

【0035】

FIG. 9 is a schematic view illustrating the configuration of the concentrating photovoltaic power generation device 80. The condensing type solar power generation device 80 is formed of, for example, a synthetic resin having low thermal conductivity, and has a case 90 in which the partial cylindrical surface side opens in a partial cylindrical shape, and the case 90 in order to function as a primary condensing device. A plurality of lens pieces are fitted into the aperture to form a partially cylindrical non-imaging Frenel lens 92, and the non-imaging Frenel lens 92 is fixed to the bottom surface of the case 90, which is the focusing position of the non-imaging Frenel lens 92. It has a seat plate 94, a secondary condensing lens 96 and a condensing solar cell 100 arranged in an overlapping state on the upper surface 94a of the seat plate 94, as shown by the one-point chain line in FIG. In addition, when sunlight is focused on the condensing solar cell 100 through the secondary condensing lens 96, the power generated from the condensing solar cell 100 is output. .. Further, the case 90 includes a fan-shaped portion 90a having a fan-shaped cross-sectional shape, a flat surface portion 90b substantially parallel to the light receiving surface 102 of the condensing solar cell 100, and a connecting portion 90c fixed to the seat plate 94. A reflective sheet 98 for reflecting sunlight is attached to the inner surface of the flat surface portion 90b. Further, the seat plate 94 is formed of an aluminum alloy or the like into a plate shape having a thickness of, for example, about 3 (mm), and a white alumite film of about 5 (μm) is formed on the upper surface 94a thereof, for example, after buffing. By applying the mirror surface treatment such as, the mirror surface has a reflectance of about 91%, and the lower surface 94b is painted, colored alumite treated, laminated with colored resin, or colored with black chrome plating or the like. As a result, it is colored, for example, black, brown, dark green, or the like.

【0036】

The concentrating solar cell 100 has a long plate shape as shown in FIG. 10, for example. On the light receiving surface 102 of the condensing solar cell 100, a large number of relatively thin comb-shaped electrodes 104 arranged parallel to the short side direction (width direction, that is, the y direction) at regular intervals in the longitudinal direction. And a pair of relatively thick bus bars (collecting electrodes) provided in a state of being connected to the comb-shaped electrode 104 at the side edge in the longitudinal direction (x direction) of the light receiving surface 102, that is, the side edge along the long side. 106 and are formed. The comb-shaped electrode 104 and the bus bar 106 form an upper electrode located on the light receiving surface 102 of the concentrating solar cell 100, and a lower surface electrode 108 is formed on the lower surface. The comb-shaped electrode 104 has a relatively narrow width dimension of, for example, about 10 μm in order to reduce the shade loss as much as possible, and in order to gradually reduce the loss due to the distributed diode effect due to current concentration. They are arranged so as to have equal density on the light receiving surface 102 at a relatively small interval of about 0.25 mm.

【0037】

FIG. 11 is a cross-sectional view showing the vicinity of the condensing solar cell 100 in the condensing photovoltaic cell 80, cut along a plane substantially perpendicular to the light receiving surface 102 of the condensing solar cell 100. .. In the concentrating photovoltaic power generation device 80 of the present embodiment, since the upper surface 94a of the seat plate 94 is a mirror surface, most of the sunlight radiated from the outside onto the seat plate 94 is reflected by the upper surface 94a. , The temperature rise of the seat plate 94 can be suitably suppressed. Further, by coloring the lower surface 94b of the seat plate 94 to a color having low brightness such as black, brown, or dark green as described above, heat is efficiently radiated from the lower surface 94b of the seat plate 94 by heat radiation. Further, since a reflective sheet 98 for reflecting sunlight is attached to the inner surface of the flat surface portion 90b of the case 90, most of the diffused light is reflected by the reflective sheet 98 as shown in FIG. It is made to radiate to the outside via the non-imaging Fresnel lens 92. Further, since the case 90 is formed of a synthetic resin having a low thermal conductivity and the reflective sheet 98 and the seat plate 94 are thermally insulated from each other, the temperature rise of the seat plate 94 is suitably suppressed. can do. With such a configuration, the condensing solar cell 100 can be maintained in a suitable temperature range.

【0038】

Although a preferred embodiment of the present invention has been described in detail with reference to the drawings, the present invention is not limited to this, and is also carried out in still another embodiment.

【0039】

For example, in the above-described embodiment, concentrating photovoltaic devices 10, 70, and 80 including multi-junction solar cells 32, 100 made of a compound semiconductor have been described, but the present invention includes the present invention. The present invention is not limited to this, and is suitably applied to, for example, a concentrating photovoltaic power generation device including a single-junction condensing solar cell made of a silicon-based semiconductor.

【0040】

Further, the seat plates 30 and 94 of the above-described embodiment are those whose upper surfaces 30a and 94a are mirror-treated, but the surface treatments applied to the upper surfaces 30a and 94a are not necessarily limited to mirror treatment. For example, the upper surfaces 30a and 94a of the seat plates 30 and 94 may be coated with white to suppress the temperature rise of the seat plates 30 and 94. Even with such a configuration, the condensing solar cell can be sufficiently maintained in a suitable temperature range.

【0041】

Further, in the concentrating photovoltaic power generation device 70 of the above-described embodiment, a light-shielding plate 74 having a mirror surface treatment on one side is provided on the upper surface 30a side of the seat plate 30, but this light-shielding plate is, for example, It is installed so that one side is painted white and that side is the side to be irradiated with sunlight, and by blocking the diffused light contained in the sunlight, the seat plate 30 is prevented from being irradiated with the diffused light. It may be a thing. If the light-shielding plate is installed so as to be thermally insulated from the seat plate 30, such a configuration can sufficiently maintain the condensing solar cell in a suitable temperature range.

【0042】

Further, in the above-described embodiment, since the seat plates 30 and 94 have a function as a radiator, a separate radiator is not installed in the vicinity of the seat plates 30 and 94. A simple radiator may be provided on the back surface of the 94.

【0043】

Although not illustrated one by one, the present invention is carried out with various modifications without departing from the spirit of the present invention.

[Simple explanation of drawings]

[Figure 1]

It is a perspective view of the solar tracking apparatus which uses the condensing type photovoltaic power generation apparatus which is one Example of this invention.

[Figure 2]

It is a figure which shows the structure of the condensing type photovoltaic power generation apparatus which is one Example of this invention, (a) is a plan view, (b) is a schematic cross-sectional view which is cut by the alternate long and short dash line of (a). ..

[Fig. 3]

It is a structural drawing explaining the structure of the condensing type solar cell used in the condensing type solar power generation apparatus which is one Example of this invention.

[Fig. 4]

It is a perspective view which shows the tubular reflector used in the condensing type photovoltaic power generation apparatus which is one Example of this invention.

[Fig. 5]

It is sectional drawing which shows the neighborhood of the condensing type solar cell in the condensing type photovoltaic power generation apparatus which is one Example of this invention cut by the plane substantially perpendicular to the light receiving surface of the condensing type solar cell.

[Fig. 6]

It is a figure which shows the structure of the condensing type photovoltaic power generation apparatus which is another Example of this invention, (a) is a plan view, (b) is a schematic cross-sectional view which is cut by the alternate long and short dash line of (a). is there.

[Fig. 7]

It is sectional drawing which shows the neighborhood of the condensing type solar cell in the condensing type photovoltaic power generation apparatus which is another Example of this invention cut by the plane substantially perpendicular to the light receiving surface of the condensing type solar cell. ..

[Fig. 8]

It is a perspective view of the solar tracking apparatus which uses the condensing type photovoltaic power generation apparatus which is still another Example of this invention.

[Fig. 9]

It is the schematic explaining the structure of the condensing type photovoltaic power generation apparatus which is still another Example of this invention.

[Fig. 10]

It is a perspective view which shows the condensing type solar cell used in the condensing type photovoltaic power generation apparatus which is still another Example of this invention.

[Fig. 11]

FIG. 5 is a cross-sectional view showing the vicinity of a condensing solar cell in a condensing photovoltaic cell according to still another embodiment of the present invention, cut along a plane substantially perpendicular to the light receiving surface of the condensing solar cell. is there.

[Explanation of symbols]

10: Concentrating solar power generation device 28: Non-imaging Fresnel lens (primary optical system) 30: Seat plate 30a: Top surface of seat plate 30b: Underside of seat plate 32: Condensing solar cell 40: Light receiving surface 70: Concentrating solar power generator 74: Shading plate 80: Concentrating solar power generator 92: Non-imaging Fresnel lens (primary optical system) 94: Seat plate 94a: Top surface of seat plate 94b: Underside of seat plate 98: Reflective sheet (shading plate) 100: Condensing solar cell 102: Light receiving surface