JP2008311408A - Concentrating solar cell module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a concentrating solar cell module comprising a condensing lens for collecting sunlight and a solar cell for generating electric power by the condensed sunlight, which can be used as a small, light and portable power supply device Provision of battery modules.
SOLUTION: A transparent plate substrate 3 is disposed between a Fresnel lens 1 and a Si single crystal solar cell 2, and a plurality of Fresnel lenses 1, 1... Are provided on the surface of the transparent plate substrate 3. A plurality of Si single crystal solar cells 2, 2... Are bonded to the back surface of the transparent plate substrate 3.
[Selection] Figure 1

Description

  The present invention relates to a concentrating solar cell module that generates power by irradiating solar cells with sunlight collected by a condensing lens for the purpose of improving photoelectric conversion efficiency and reducing system cost.

  In the concentrating solar cell module configured to collect sunlight with a condensing lens and irradiate the solar cell with this, the photoelectric conversion efficiency is improved as compared with the case of non-condensing, and further, the solar cell It has been known that system costs and power generation costs can be reduced because the amount of materials used can be reduced. Therefore, many patent applications have been filed for the concentrating solar cell module.

For example, a “concentrating solar cell module and concentrating solar power generation system” according to Japanese Patent Application Laid-Open No. 2002-289900 condenses solar light on a photovoltaic element without unevenness in light amount and chromatic aberration and with high efficiency. It is a compact, lightweight and inexpensive concentrating solar cell module.
Therefore, in a concentrating solar cell module having a light guide having at least one exit surface and a plurality of entrance surfaces, and at least one photovoltaic element immediately after the exit surface, the light guide is transmissive. A solid medium with no refractive index discontinuous part, the surface has smoothness, and the solar radiation radiated from the sun is totally incident on the incident surface of the light guide. Then, it can be totally reflected and emitted from the exit surface.

The “concentrating solar cell module and concentrating solar power generation system” according to Japanese Patent Application Laid-Open No. 2002-289896 eliminates unevenness in light intensity and chromatic aberration of solar rays, and suppresses temperature rise, particularly uneven temperature rise, of photovoltaic elements. It has a function.
Therefore, a primary optical system that condenses solar rays emitted from the sun, a secondary optical system that guides the condensed solar rays to the photovoltaic elements, and a photovoltaic element disposed immediately after the secondary optical system In the concentrating solar cell module, the secondary optical system is a solid heat ray absorbing member having transparency, and the heat radiating member is in contact with the secondary optical system.

  Usually, since the solar cell is arranged near the focal point of the condensing lens, a gap is formed between the condensing lens and the solar cell, and the “condensing type” described in JP-A-2002-289900 is formed in the gap. The “solar cell module and concentrating solar power generation system” includes a light guide unit that guides sunlight collected by the condensing lens to the solar cell.

  In addition, in the “condensing solar cell module and concentrating solar power generation system” according to Japanese Patent Laid-Open No. 2002-289896, a secondary optical system for mixing light from a condensing lens and reducing chromatic aberration and the like is provided. Each structure is arranged. As described above, many conventional concentrating solar cell modules have a complicated structure and a large structure. This is because the concentrating solar cell module itself is designed and manufactured on the premise that it is fixed to another solid and strong base.

  On the other hand, recently, there is an increasing need to use concentrating solar cell modules to generate driveable power for notebook personal computers and liquid crystal televisions in emergency portable power supplies in the event of a disaster. In some cases, the solar cell module is required to be small, light and robust. However, it is difficult to apply the concentrating solar cell module having a complicated and large structure as described above to a portable power supply device.

“Concentrator and concentrating solar cell module” according to Japanese Patent Laid-Open No. 2001-189487 uses a concentrator capable of condensing most incident light on a solar cell regardless of the direction of the sun, and this concentrator. It is a concentrating solar cell.
Therefore, the refractive index is made of a transparent material larger than air, the cross section has a trapezoidal shape, and one of the opposing corners on the diagonal line in the trapezoid is 90 degrees or more and the other corner is More than 90 degrees, the light incident surface on which light is incident and the light emitting surface from which light is emitted are parallel, the light incident surface is larger than the light emitting surface, and the other two surfaces have reflecting films. A concentrator provided is used, and a solar cell is mounted on the light exit surface of the concentrator.

A “concentrating solar cell module” according to Japanese Patent Laid-Open No. 6-37344 is an inexpensive concentrating solar cell module in which a solar cell and a module are integrated.
Therefore, when light is incident at an angle θ _m from the right direction, the lens refracting surface has an elliptical shape having a major axis in the incident angle direction (the focal position is −d), and an extension line connecting the focal points −d and + d and an elliptical shape. Intersections with the refracting surface are denoted by c and c ′, and points at which the inclination of the tangent line is infinite are denoted by a and a ′. For the incident light in the right direction, the arc cb is the lens refracting surface. In addition, for the light incident from the left direction at the same incident angle, the designed lens refracting surface has an elliptical shape (focus position is + d) indicated by a broken line, which is y-axis symmetric with the above shape, and an arc on the right part thereof Let c′b ′ be a refractive surface. When the shapes of the two left and right lenses are combined, the resulting lens cross section has a shape connecting points c, a, b, a ′, c ′, + d, −d, c, and the lower surface cc of this refractive non-imaging lens. For example, if the solar cell 5 is bonded to the focal distance 2d, the solar cell and the module are integrated.

These are simple because they have a structure in which a solar cell is arranged on the back surface of the condenser and the condenser lens. However, when a module in which a plurality of condenser lenses are combined is used, a base for fixing the condenser lens is used. Is newly required. This results in a complicated structure.
“Concentrating solar cell module and concentrating solar power generation system” according to Japanese Patent Application Laid-Open No. 2002-289900 "Concentrating solar cell module and concentrating solar power generation system" according to Japanese Patent Application Laid-Open No. 2002-289896 "Concentrator and concentrating solar cell module" according to Japanese Patent Application Laid-Open No. 2001-189487 "Concentrating solar cell module" according to JP-A-6-37344

  As described above, the conventional concentrating solar cell module has the above-described problems. The problems to be solved by the present invention are these problems, and provide a concentrating solar cell module that can be used as a compact, lightweight and portable power supply.

  In the concentrating solar cell module according to the present invention, a plate-shaped substrate transparent to sunlight is disposed between the condensing lens and the solar cell, and the condensing lens is disposed on the surface side of the plate-shaped substrate. By arranging the solar cell on the side, the transparent plate-like substrate is structured to function as a light guide and a housing. Moreover, the concentrating solar cell module of the present invention is configured by arranging a plurality of condensing lenses and a plurality of solar cells on the transparent plate-like substrate. Here, although the condensing lens and solar cell which are arrange | positioned at the front and back of a transparent plate-shaped base | substrate are generally adhere | attached, other attachment structures are also included. For example, a concave portion or a convex portion may be provided on the front and back surfaces of the transparent plate substrate, and a convex portion or a concave portion that meshes with these concave and convex portions may be formed on the joint surface between the condenser lens and the solar cell.

  The concentrating solar cell module according to the present invention has a remarkably simple structure because the transparent plate-like substrate functions as a light guide and a housing, and a gap between the condensing lens and the solar cell. Because there is no, it becomes a very robust structure. The configuration of the present invention is the same as that of the “concentrator and concentrating solar cell module” according to Japanese Patent Laid-Open No. 2001-189487 and “concentrating solar cell module” according to Japanese Patent Laid-Open No. 6-37344. Although it seems to be similar, the transparent plate-like substrate has a completely different function from the condenser or the condenser lens, and as a result, a module in which a plurality of condenser lenses are combined can be configured.

  The transparent plate-like substrate can function as a part for fixing the condenser lens, and therefore, no other parts or jigs are required. That is, the concentrating solar cell module of the present invention has a simple structure and production, and is suitable as a small and lightweight portable power supply device.

  FIG. 1 is an embodiment showing a concentrating solar cell module according to the present invention. In FIG. 1, 1 is a Fresnel lens, 2 is a Si single crystal solar cell, 3 is a transparent plate substrate, and 4 is a backside heat dissipation. The plates 5 indicate sunlight. In this solar cell module, sunlight 5 is collected by the Fresnel lens 1, passes through the transparent plate-like substrate 3, and is irradiated onto the Si single crystal solar cell 2. As a result, electricity is generated in the Si single crystal solar cell 2.

  In this embodiment, the size of the Fresnel lens 1 is 50 mm × 50 mm, the size of the Si single crystal solar cell 2 is 13 mm × 13 mm, and these are bonded to both surfaces of the transparent plate-like substrate 3. The transparent plate-like substrate 3 is PMMA (polymethyl methacrylate) having a thickness of 10 mm, the Fresnel lens 1 is bonded to the surface of the PMMA plate, and the Si single crystal solar cell 2 is bonded to the back surface of the PMMA plate.

  In this case, the sunlight 5 is condensed 14.8 times and irradiated to the Si single crystal solar cell 2. In this embodiment, the Fresnel lens 1 and the transparent plate-like substrate 3 are both made of PMMA, and are bonded with an adhesive having the same refractive index as that of the two so that sunlight at the boundary between the two can be obtained. There is no reflection loss of 5. Here, polycarbonate may be used in addition to PMMA as the material of the Fresnel lens 1 and the transparent plate substrate 3.

  FIG. 2 is a plan view showing the surface of the concentrating solar cell module. Fresnel lenses 1, 1... Are arranged and bonded in the vertical and horizontal directions on the surface of the transparent plate-like substrate 3 of 200 mm × 200 mm without gaps. Also, as shown in FIG. 3, Si single crystal solar cells 2, 2. Further, rear heat sinks 4, 4,... Are bonded to the back surfaces of the Si single crystal solar cells 2, 2,.

  In this way, a concentrating solar cell module (size 200 mm × 200 mm) using 16 Fresnel lenses 1, 1... And 16 Si single crystal solar cells 2, 2,. The output characteristics were measured under the conditions of mass 1.5 and 100 mV / cm 2. As a result, an electric power of 7.2 W was obtained, and it was confirmed that the electric power was 1.3 times that of a non-condensing solar cell module of the same size.

  In this case, when the temperature of the Si single crystal solar cell 2 during the condensing operation was measured, only a temperature increase of 2 ° C. was observed compared to the case of the non-condensing solar cell module. This is a result of the heat dissipation effect of the aluminum plate used as the backside radiation plate 4. In this example, the Si single crystal solar cell 2 is used as the solar cell. However, the power itself obtained even when using a polycrystalline or non-condensed Si solar cell reaches the single crystal Si solar cell. There is not, but it is possible to get some power.

  FIG. 4 shows a concentrating solar cell module as another embodiment according to the present invention. In the figure, 6 is an InGaP / GaAs / Ge3 junction tandem solar cell, 7 is a transparent plate-like substrate having a non-uniform thickness, 8 is an electricity storage device, and 9 is an inverter circuit. In this solar cell module, an InGaP / GaAs / Ge3-junction tandem solar cell 6 is used as a solar cell for condensing operation, and the transparent plate-like substrate 7 is thickest in the solar cell arrangement part. It becomes thinner as you move away.

  By using such a transparent plate-like substrate 7, the weight of the PMMA plate as the transparent plate-like substrate 7 can be reduced to about 60% as compared with a PMMA plate having a uniform thickness. The InGaP / GaAs / Ge3 junction tandem solar cell 6 has an exchange efficiency of 27% even in a non-condensing operation, but it can be reduced to 33% by performing a condensing operation of 14.8 times as in the case of the above embodiment. Improved.

  16 pieces of this InGaP / GaAs / Ge3 junction tandem solar cell 6, 6... Having a size of 13 mm × 13 mm, and 16 pieces of Fresnel lenses 1, 1... Having a size of 50 mm × 50 mm are used. A concentrating solar cell module is formed by bonding to a transparent plate-like substrate 7 having a size of 200 mm. As a result, it was possible to obtain 13.2 W of electric power based on pseudo solar air-mass 1.5, 100 mV / cm 2.

  Further, in this case, since the portion other than the portion through which sunlight passes in the transparent plate-like substrate 7 is deleted by cutting, an electric double layer capacitor or inverter circuit 9 as the electricity storage device 8 is provided in the space (gap). The space can be effectively used, and the structure of the solar cell module can be made extremely compact. That is, as shown in FIG. 4, as the distance from the InGaP / GaAs / Ge 3 junction tandem solar cell 6 increases, the thickness of the transparent plate-like substrate 7 decreases, and a gap is formed between the rear heat sink 4. Is done. The storage device 8 and the inverter circuit 9 are set using this gap.

1 is a cross-sectional view of a concentrating solar cell module according to the present invention. The top view of the concentrating solar cell module according to the present invention. The bottom view of the concentrating solar cell module according to the present invention. 1 is a cross-sectional view of a concentrating solar cell module according to the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Fresnel lens 2 Si single crystal solar cell 3 Transparent plate-like base body 4 Back surface heat sink 5 Sunlight 6 InGaP / GaAs / Ge3 junction tandem solar cell 7 Transparent plate-like base body 8 Electric storage device 9 Inverter circuit

Claims (8)

In a concentrating solar cell module comprising a condensing lens that collects sunlight and a solar cell that generates electricity using the condensed sunlight, a transparent plate-like substrate is disposed between the condensing lens and the solar cell. A concentrating solar cell module having a structure, wherein a plurality of condensing lenses are arranged on the surface of the transparent plate substrate, and a plurality of solar cells are arranged on the back surface of the transparent plate substrate. The condensing according to claim 1, wherein the thickness of the transparent plate-like substrate disposed between the condensing lens and the solar cell is the thickest in the solar cell arrangement portion and becomes thinner as the distance from the solar cell arrangement portion increases. Type solar cell module. The concentrating solar cell module according to claim 1, wherein the condensing lens in which a transparent plate-like substrate is disposed between the solar cell and the solar cell is a Fresnel lens. The concentrating solar cell module according to claim 1, wherein the solar cell in which a transparent plate-like substrate is disposed between the condensing lens is an Si solar cell. 4. The concentrating solar cell according to claim 1, wherein the solar cell having a transparent plate-like substrate disposed between the condensing lens is a GaInP / GaAs / Ge3 junction tandem solar cell. module. The concentrating solar cell module according to claim 1, wherein the solar cell in which the transparent plate-like substrate is disposed between the condensing lens is a CuInGaSSe ₂ solar cell. The said transparent plate-shaped base | substrate arrange | positioned between a condensing lens and a solar cell was made into PMMA (polymethylmethacrylate), Claim 2, Claim 3, Claim 4, Claim 5, or Claim. 6. The concentrating solar cell module according to 6. In a concentrating solar cell module comprising a condensing lens that collects sunlight and a solar cell that generates electricity using the condensed sunlight, a transparent plate-like substrate is disposed between the condensing lens and the solar cell. A plurality of condensing lenses are arranged on the surface of the transparent plate-like substrate, and a plurality of solar cells are arranged on the back surface of the transparent plate-like substrate, and a rear heat sink is arranged on the back surface of the solar cells. And, the thickness of the transparent plate-shaped substrate is the thickest at the solar cell arrangement part, and is thinned away from the solar cell arrangement part. A concentrating solar cell module in which an electricity storage device and an inverter are arranged.

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