JP2006332535A - Convergent solar cell module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a structure capable of efficiently radiating heat generated in a solar cell and suppressing the weight of a module to a minimum in a convergent solar cell module. <P>SOLUTION: An efficient radiation of heat generated in a solar cell can be maintained and an increase in the weight of the module can be suppressed, by defining the thickness and outer size of an electrode plate to which the solar cell is fixed in a certain range. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a technology of a concentrating solar cell module, and more specifically to a concentrating solar cell module structure excellent in heat dissipation.

In recent years, development of clean energy has been demanded due to problems such as depletion of energy resources and global environmental problems such as increased CO ₂ in the atmosphere. In particular, solar power generation using solar cells has been developed and used as a new energy source. It has become. The solar power generation system is desired to be reduced in cost for further spread. The concentrating solar power generation system is promising as a system that reduces the amount of solar cells that are the most expensive components in the solar power generation system and reduces the cost of the entire system.

  A conventional example of a concentrating solar cell module will be described with reference to the drawings. FIG. 8 is a schematic view of a conventional concentrating solar cell module, and FIG. 9 is a schematic cross-sectional view of the conventional concentrating solar cell module. A plurality of Fresnel lenses 12 are arranged in an array on the sunlight incident side of the rectangular parallelepiped case 11. Each Fresnel lens 12 is provided with a corresponding solar battery cell 23. In order to make the light condensed by the Fresnel lens 12 enter the solar battery cell 23, it is necessary to set so that the sunlight 13 enters the Fresnel lens 12 perpendicularly.

In order to set so that the sunlight 13 enters the Fresnel lens 12 perpendicularly, it is necessary to track the entire case 11 so that it always faces the sun. In general, two rotation shafts are provided between the case 11 and the system installation surface, and the sun tracking is performed by rotationally driving the two shafts by a motor or hydraulic drive. The solar azimuth and solar altitude are calculated by the formula of the solar orbit and the latitude, longitude and time of the installation location, and the sun tracking is performed by controlling the drive system.
The sunlight 13 incident on the Fresnel lens 12 is collected by the Fresnel lens 12 and is applied to the solar battery cell 23 installed on the support plate portion 11 a that supports the solar battery cell 23 on one surface of the case 11 facing the Fresnel lens 12. Irradiated. Condensation magnification is several tens of times to several hundreds of times, and solar cells are irradiated with sunlight having a large energy density. Since the power generation efficiency of solar cells decreases with increasing temperature, a heat dissipation mechanism is required.
In general, the support plate portion 11a is made of a material having a high thermal conductivity such as a metal, and the support plate portion 11a uses the support plate portion 11a to dissipate heat through the back surface of the solar battery cell 23. The structure which provided the fin for heat radiation is taken so that the surface area of the back side may become large.

In Patent Document 1, regarding solar cell fixing in a concentrating solar power generation system, a metal foil is soldered to the entire back electrode of the solar cell, the electrode is taken out by this metal foil, and the metal foil is thermally conductive. The structure which implement | achieves the electrode extraction of a photovoltaic cell, fixation, and thermal radiation by adhere | attaching on a seat plate with the thermal radiation layer which consists of an epoxy resin adhesive containing an additive is disclosed. In addition, there is a description that the width of the metal foil is preferably larger than the width of the solar battery cell for efficient heat dissipation.
Patent Document 2 describes a structure of a primary optical system of a concentrating solar cell system, solar cell fixing and electrode extraction portions. A structure is disclosed in which a back electrode of a solar battery cell is soldered to a heat sink, the electrode is taken out from the heat sink, and the heat sink is fixed to a support plate via an electric insulating layer.
JP 2003-174179 A US Pat. No. 6,399,874

However, the solar cell fixing method of Patent Document 1 has the following problems. When the heat generated in the solar battery cell is conducted to the seat plate having a heat radiation mechanism to the atmosphere, it is necessary to conduct a heat radiation layer made of an epoxy resin containing a metal foil and a heat conductive additive. Even when the area of the metal foil is larger than the area of the solar battery cell, the metal foil is very thin with a thickness of 0.1 mm. Therefore, the thermal resistance in the surface direction of the metal foil is large, and the heat diffusion from the solar battery cell to the outside direction. Not enough. When heat diffusion to the outside is not sufficiently performed, the heat conduction area of the heat dissipation layer made of epoxy resin remains in a small region near the solar battery cell, so that the heat resistance of the heat dissipation layer increases. Since the heat conductivity of the heat dissipation layer is about two orders of magnitude lower than that of metal, this problem leads to deterioration of heat dissipation characteristics. That is, in the case of the structure of Patent Document 1, the heat conduction generated in the solar cell is rate-determined in the heat dissipation layer part and stays in the solar cell, so that the heat dissipation is not sufficiently performed and the temperature of the solar cell rises. There is a problem such as.
In Patent Document 2, there is no description of the material, thickness, and size of the heat sink. When the heat sink is thin, the same problem as in Patent Document 1 can be considered. When the heat sink has a small outer size, the heat dissipation characteristics deteriorate. Problems arise.

  The present invention has been made in view of the above points, and by finding a structure in which the heat dissipation characteristics of solar cells can be most efficiently obtained, a concentrating type that minimizes the maintenance of the heat dissipation characteristics and the reduction of the module weight. An object is to provide a solar cell module.

In order to achieve the above object, the present invention provides a solar cell having electrodes on the front surface and the back surface, an electrode plate electrically connected to the back electrode of the solar cell by solder, and a heat dissipation electrical insulating layer. A concentrating solar cell module including a support plate for supporting the electrode plate, wherein the electrode plate constitutes a wiring member to the outside on the back electrode side of the solar cell and is larger than the size of the solar cell. And, when the thickness of the electrode plate is t (mm) and the thermal conductivity of the electrode plate is λ (W / K / m), λ × t is 160 or more and 2000 or less. It was a module.
According to this structure, the heat generated in the solar battery cell is conducted to the electrode plate through the solder, diffused to the outside of the solar battery cell by the electrode plate having a certain thickness, and then the heat dissipation with low thermal conductivity. Since the electrical insulating layer is conducted, the conduction cross-sectional area of the radiating electrical insulating layer is increased, and the thermal resistance can be reduced. As a result, the heat dissipation characteristics from the solar battery cell are improved, and the temperature of the solar battery cell can be suppressed lower. If λ × t is smaller than 160, the thermal diffusion of the electrode plate toward the outside of the solar battery cell becomes insufficient, and the heat dissipation characteristics deteriorate. In addition, the larger the λ × t, the lower the solar cell temperature can be, but if it exceeds 2000, the solar cell temperature reduction effect will be saturated, while the increase in t will increase the weight of the entire module. It is desirable to be smaller than this value.

In the present invention, λ × t of the electrode plate is preferably 400 or more and 1200 or less.
According to this structure, the heat dissipation characteristics are good, and the thickness of the electrode plate is not unnecessarily thick, so that an increase in the weight of the module can be suppressed.

In the present invention, it is preferable that the outer size of the electrode plate is not less than 3 times and not more than 10 times the outer size of the solar battery cell.
According to this structure, when the outer size of the electrode plate is smaller than three times the outer size of the solar cell, the heat dissipation efficiency is poor and the temperature of the solar cell portion is increased. Moreover, when the outer size of the electrode plate is larger than 10 times the outer size of the solar cell, the temperature drop of the solar cell with respect to the increase of the outer size is reduced, and even if the outer size of the electrode plate is increased, the improvement of the heat dissipation efficiency is small. Since this increases the weight of the entire module, it is desirable to be smaller than this value.

In the present invention, the outer size of the electrode plate is more preferably 6 to 9 times the outer size of the solar battery cell.
According to this structure, it is possible to maintain heat dissipation characteristics and suppress an unnecessary increase in module weight.

In the present invention, the electrode plate is preferably made of metal as a main material.
According to this configuration, by using a metal as the main material of the electrode plate, there is an advantage that the heat conductivity of the electrode plate is high and good heat dissipation characteristics can be maintained.

In the present invention, the electrode plate is preferably made of copper as a main material.
According to this configuration, since the electrode plate is made of copper, the adhesion between the copper and the solder is good, so that the solar battery cell and the electrode plate can be easily joined by solder and is also commercially inexpensive. There is an advantage that it can be obtained.

In the present invention, the thickness of the electrode plate made mainly of copper is preferably 1 mm to 3 mm.
According to this structure, the heat dissipation characteristics are good and the thickness of the electrode plate is not thicker than necessary, so that an increase in weight can be suppressed.

In the present invention, an electrical insulating layer is formed on at least a part of the upper surface of the electrode plate, and the surface electrode side lead wiring of the solar battery cell is disposed on the electrical insulating layer.
According to this structure, the electrical insulating layer is patterned on the electrode plate that is electrically connected to the back electrode of the solar battery cell, and the wiring that is electrically connected to the front electrode of the solar battery cell is patterned on the electrical insulating layer. And a wiring pattern can be formed on the electrode plate. This wiring pattern can be used, for example, for attachment of a bypass diode and connection with other solar cells. Since the upper surface of the electrode plate is inside the case of the concentrating solar cell module and there is little air convection and almost no heat dissipation effect, even if an electrical insulation layer is formed on the upper surface of the electrode plate, the heat dissipation characteristics are almost affected. Absent.

In the present invention, it is desirable that the electrical insulating layer is a resist mainly composed of an acrylic resin.
According to this structure, it can apply | coat by printing, spraying, etc. on the said electrode plate, and the patterning of the layer which has the said electrical insulation can be performed easily.

According to the structure of the present invention, it is possible to provide a concentrating solar cell module that can efficiently dissipate the heat generated in the solar cells and suppress an increase in weight. The heat generated in the solar cell is conducted from the back surface of the solar cell to the electrode plate via solder, diffuses to the outside of the solar cell through the electrode plate, and then conducts through the heat-dissipating electrical insulating layer, so that heat conduction It is possible to reduce the thermal resistance of the heat dissipating electrical insulating layer having the lowest rate, and to improve the heat dissipation characteristics as a whole. In this process, it is most important to diffuse the heat to the outside of the solar cell by the electrode plate. In the present invention, by optimizing the size and material of the electrode plate, the heat dissipation characteristics can be maintained and the module weight can be reduced. It becomes possible to make it compatible.
When the heat dissipation characteristics are improved, the temperature of the solar battery cell can be kept low, and the decrease in the solar battery cell output accompanying the temperature rise can be suppressed. Moreover, the weight increase of the whole module can be suppressed by making the thickness of the electrode plate and the outer size the minimum while maintaining the heat dissipation characteristics. If the weight of the module can be reduced, the load on the drive system for solar tracking will be reduced, contributing to simplification of the drive system and cost reduction.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic sectional view of a concentrating solar cell module according to an embodiment of the present invention. One end surface of the rectangular parallelepiped case 11 is open, and the Fresnel lens 12 is fixed to the opening. A plurality of Fresnel lenses 12 may be fixed, or a plurality of Fresnel lens patterns may be formed on one surface. In the case where a plurality of Fresnel lens patterns are formed on one sheet, it is difficult for the lens to shift, so that the alignment shift between the Fresnel lens 12 and the solar battery cell 23 can be suppressed.
As the material of the case 11, aluminum that is lightweight and has good thermal conductivity is suitable. However, a stainless plate, a steel plate, or a steel plate plated with an alloy such as zinc, aluminum, or silicon may be used. Examples of the material of the Fresnel lens 12 include translucent materials such as acrylic resin, polycarbonate, UV curable resin, and glass.
In FIG. 1, solar cells 23 are fixed to a support plate portion 11 a facing the Fresnel lens 12 of the case 11. Sunlight condensed by the Fresnel lens 12 is irradiated to the solar cell 23. The concentration factor of sunlight is about 700 times at maximum. FIG. 2 shows an enlarged perspective view of a fixed portion of the solar battery cell 23. The solar battery cell 23 is fixed to the electrode plate 42 with solder, and the electrode plate 42 is fixed to the support plate portion 11 a and the electric insulating screw 27 through the heat dissipation electric insulating layer 41.

  As the solar battery cell 23, an inorganic solar battery cell made of Si, GaAs, CuInGaSe, CdTe or the like can be used, and the structure of the solar battery cell is a single junction cell or a monolithic multi-junction cell. Alternatively, a mechanical stack cell in which various solar cells having different sensitivity regions are connected can be used. In the concentrating solar power generation system, there is an object of suppressing the usage amount of the solar battery cell for cost reduction, and the size of the solar battery cell 23 is preferably smaller and thinner. The thickness of the solar cell 23 is about 100 μm to 200 μm, and the outer size of the solar cell 23 is about several mm to 20 mm. The outer size of the solar battery cell 23 is determined from the effective light collection area of the Fresnel lens 12 and a desired light collection magnification.

FIG. 3 shows an enlarged cross-sectional view of the fixing portion of the solar battery cell 23 which is a cut surface in 2a-2b of FIG. A heat-dissipating electrical insulating layer 41 made of a heat conductive material having electrical insulation is provided on the upper surface of the support plate portion 11a that fixes the solar battery cell 23, and a structure in contact with the lower surface of the upper electrode plate 42 is provided.
The heat-dissipating electrical insulating layer 41 is preferably made of epoxy resin, silicone resin or the like as a main material, and as an additive, metal such as gold, silver, copper, aluminum, magnesium, iron, stainless steel, aluminum oxide, magnesium oxide, oxidation What added one or more metal oxides, such as zinc, boron nitride, aluminum nitride, carbon, etc. is used. The electrode plate 42 is preferably made mainly of a metal or alloy having a high thermal conductivity. For example, it can be a simple metal such as gold, silver, copper, aluminum, magnesium, iron, nickel, tin, stainless steel, or an alloy thereof. In particular, copper is suitable as a material for the electrode plate 42 because it is easily available commercially at a low cost, has a high thermal conductivity, and has good bonding properties with solder.

  An electrical insulating layer 24 is provided on at least a portion of the upper surface of the electrode plate 42 other than the portion where the solar battery cells 23 are joined. A metal foil 21a is provided on the upper surface of the electrical insulating layer 24, and the metal foil 21a and the surface electrode 22 of the solar battery cell 23 are electrically joined by metal wire bonding. The extraction of the wiring from the metal foil 21a to the outside is performed by soldering the external extraction line 25 and the metal foil 21a, and the extraction of the wiring from the electrode plate 42 to the outside is performed by soldering the external extraction line 26 to the surface of the electrode plate 42. It is done by attaching.

The electrical insulation layer 24 is provided to maintain electrical insulation between the metal foil 21a of the solar cell and the electrode plate 42. By patterning together with the metal foil 21a, wiring patterning is possible on the electrode plate 42. For example, by providing the opening of the electrical insulating layer 24 and the metal foil 21a in a close position, the bypass diode of the solar battery cell 23 can be attached to that portion. The patterning of the electrical insulating layer 24 can be performed by bonding a film made of acrylic, nylon, PET, polyimide, or the like, or by applying a resist mainly composed of these materials by printing, spraying, or the like. it can. As the material of the metal foil 21a, gold, silver, copper, tin or the like can be used.
The entire surface of the back electrode of the solar battery cell 23 is joined by solder 43 to a portion of the electrode plate 42 where the electrical insulating layer 24 is not provided at the center of the upper surface. The electrode plate 42 is fixed to the support plate portion 11a via the heat-dissipating electric insulating layer 41 with an electric insulating screw.

  By adopting this structure, sunlight 13 collected by the Fresnel lens 12 is irradiated to the solar cells 23 and a large amount of energy is irradiated to the solar cells 23. It is transmitted from the lower surface of the battery cell 23 to the electrode plate 42 through solder, and can be efficiently diffused in the electrode plate 42 toward the outside of the solar battery cell 23. Thereafter, the heat dissipating electrical insulating layer having thermal conductivity and electrical insulation from the electrode plate 42 41, heat can be efficiently radiated through the support plate portion 11a. By once diffusing heat to the outside of the solar battery cell 23 by the electrode plate 42, the cross-sectional area at the time of heat conduction of the heat dissipation electrical insulating layer 41 having a small thermal conductivity can be increased and the heat resistance can be reduced. improves.

  The surface of the solar battery cell 23 is covered with translucent glass or resin to improve weather resistance. Examples of the sealing material 29 include fluorine resin films such as polyethylene tetrafluoroethylene, polytrifluoride ethylene, and polyvinyl fluoride, ethylene vinyl acetate copolymer (EVA) resin, butyral resin, silicon resin, epoxy resin, fluorine Transparent resin such as fluorinated polyimide resin, acrylic resin, and PET, and glass can be used.

The material and size of each component is determined by a heat dissipation simulation.
(Heat dissipation simulation)
The heat dissipation simulation will be described in detail below.
Create a 3D model with Autodesk Inventor (R) 7 and use the simulation software COSMOS Design STAR 4.0 to conduct heat conduction analysis (steady state analysis, WNR (modified Newton-Raphson method), initial temperature 25 degrees Celsius) Went.
The support plate portion 11a is an aluminum 6061 Alloy plate (heat conductivity 170 W / K / m) of 160 mm × 200 mm × 2 mm ^t , and the heat dissipation electrical insulating layer 41 is a silicone resin containing a metal additive (heat conductivity 0.65 W / m). K / m), the electrode plate 42 is a copper plate (thermal conductivity 390 W / K / m) having an outer size of 60 mm square, and a solder 43 (thermal conductivity 31.1 W / mm) having a size of 7 mm × 7 mm and a thickness of 0.1 mm on the upper surface thereof. K / m), and a solar cell 23 (heat conductivity 59.9 W / K / m: InGaP / InGaAs / Ge three-junction compound solar cell) having an outer shape of 7 mm square and a thickness of 160 μm is basically bonded to the upper surface. and then, the volume calorific 17.15W to the solar cell 23 as an input heat source (1000W / m ²⁾ (direct solar radiation intensity) × 0.000049 (m ²⁾ (focused spot area) × 5 0 gives (sun) (500-fold condensing) × 0.7 (1-photovoltaic power generation consumption)), only the support plate portion 11a back surface was set to convection 25 ° C.. Since the air convection is small in the space on the surface of the solar battery cell 23 and the surface of the electrode plate 42, heat dissipation from the surface side is not considered in this simulation. The above conditions were set to the initial state, and the thickness of the electrode plate 42 was changed. The following results are a comparison of the maximum temperatures of the respective solar cells 23.

  First, the case where the electrode plate of the conventional example was thin foil shape (thickness 0.1 mm) and the case of plate shape (thickness 1 mm) were compared. The conditions other than the thickness of the electrode plate were the same. As a result of the simulation, the maximum temperature of the cell was as follows: foil shape (thickness 0.1 mm): 98.23 ° C., plate shape (thickness 1.0 mm): 64.04 ° C., which was about 34 ° C. FIG. 4 shows the temperature characteristics of the conversion efficiency of an InGaP / InGaAs / Ge three-junction compound solar cell. In the case of 200 times condensing, when the temperature difference of solar cells is about 34 degrees, the difference in conversion efficiency is as large as about 2% in absolute value, and this tendency does not change even under 500 times condensing.

  Next, when the thickness of the electrode plate in the initial state is 1 mm, parameters other than the thickness of the electrode plate 42 that are considered to be effective for heat dissipation (material of the heat dissipation electrical insulating layer 41, thickness of the support plate 11a) It was confirmed whether the parameter had a large influence on the heat dissipation of the solar battery cell 23. The results are shown in FIG. When the thermal conductivity of the radiating electrical insulating layer 41 is changed from 0.65 W / K / m to 3 or 5 W / K / m, compared to the case where the thickness of the support plate portion 11a is changed from 2 mm to 3 or 4 mm, It can be seen that the change in the maximum solar cell temperature is large when the thickness of the electrode plate 42 is changed from 1 mm to 2 or 3 mm. That is, it can be said that it is more effective to increase the thickness of the electrode plate 42 in order to improve the heat dissipation characteristics.

  FIG. 6 shows that in the initial state, the size of the electrode plate 42 is 10 mm × 10 mm, 40 mm × 40 mm,... 60 mm × 60 mm (the heat dissipation electrical insulating layer 41 is also the same as the size of the electrode plate 42), or the thickness is 0.1 mm. It is the simulation result of the photovoltaic cell maximum temperature at the time of changing to 5 mm from. It can be seen that when the thickness of the electrode plate is changed from 0.1 mm to 0.4 mm, the temperature of the solar battery cell is drastically lowered, and when the thickness is further increased, the temperature drop is gradually reduced. When designing from the viewpoint of heat dissipation and weight reduction of the electrode plate 42, the thickness is preferably in the range of 0.4 mm to 5.0 mm, and more preferably 1 mm to 3 mm. FIG. 6 shows a case where the material of the electrode plate 42 is copper, but the same result is obtained when the product of the thermal conductivity of the electrode plate 42 and the thickness of the electrode plate 42 is equal. For example, when aluminum whose thermal conductivity of the electrode plate 42 is 170 (W / K / m) is used, substantially the same simulation result is obtained when the thickness of the electrode plate 42 is 2.3 times. That is, when the thickness of the electrode plate 42 is t (mm) and the thermal conductivity of the electrode plate 42 is λ (W / K / m), λ × t is preferably 160 or more and 2000 or less. More preferably, it is 400 or more and 1200 or less.

  FIG. 7 shows the ratio of the outer size of the electrode plate 42 and the solar battery cell 23 on the horizontal axis when the thickness of the electrode plate 42 is 1 mm, 2 mm, and 3 mm in the initial state, It is the figure plotted on the vertical axis. When the value of the electrode plate size / solar cell size is 3 or less, the solar cell maximum temperature is high, and when it exceeds 10, the temperature drop is small. In the case of designing from the viewpoint of improving heat dissipation and reducing the weight of the electrode plate, it is more preferable that the range is 6 to 9.

  Example 1 will be described with reference to the drawings. The outline of the condensing system is the same as in FIG. 8, and the configuration of the module is the same as in FIGS. One end surface of the aluminum case 11 having a rectangular parallelepiped shape is opened, and the Fresnel lens 12 is fixed to the opening portion by an epoxy resin adhesive. As the Fresnel lens 12, an individual lens pattern formed of an acrylic resin was bonded to a glass plate with a translucent adhesive, and a Fresnel lens pattern was formed in a 7 × 5 array. The external shape of the Fresnel lens 12 was 200 mm × 200 mm, the thickness was 2 mm, and the focal length was 200 mm. The outer shape of the case 11 was 1440 mm × 1040 mm × 202 mm, and the thickness was 3 mm. A pair of Fresnel lenses 12 and solar cells 23 are provided in the case 11 in 35 pairs. The solar battery cell 23 fixed to the electrode plate 42 is fixed to the support plate portion 11 a facing the Fresnel lens 12 of the case 11. The sunlight 13 collected by the Fresnel lens 12 is irradiated to the solar battery cell 23. As the solar battery cell 23, a 7 mm square size InGaP / InGaAs / Ge3 junction type compound solar battery was used.

With this configuration, when the condensed light is applied to the entire surface of the solar battery cell, the condensing magnification is about 300 times. The thickness of the support plate part 11a was 3 mm. On the upper surface of the support plate portion 11a, a heat-dissipating electrical insulating layer 41 containing a silicone resin adhesive as a main component and aluminum as an additive was provided and adhered to the lower surface of the upper electrode plate. The heat dissipation electric insulation layer 41 had a thermal conductivity of 0.65 W / m · K and a thickness of 0.1 mm. The electrode plate 42 was a copper plate having a thickness of 2 mm and an outer size of 60 mm × 60 mm.
The shape of the solar battery cell 23 is generally rectangular from the viewpoint of ease of processing and effective utilization of materials, but it may be circular, elliptical, polygonal, or the like. Moreover, the size of the solar battery cell 23 is determined from the size of the Fresnel lens and a desired condensing magnification, and may be any size.

Based on FIG. 2, FIG. 3, taking out to the exterior of the surface electrode 22 of the photovoltaic cell 23 is demonstrated. On the electrode plate 42, a resist (25 μm thick) mainly composed of an acrylic resin is formed by patterning as an electrical insulating layer 24 by a screen printing method. A silver foil (thickness: 200 μm) is bonded onto the electrical insulating layer 24 with an epoxy resin adhesive. The surface electrode 22 of the solar battery cell 23 and the silver foil 21a are connected by aluminum wire bonding. The silver foil 21a and the external lead wire 25 were connected by soldering. The solar cell 23 was taken out from the back electrode by soldering an external lead wire 26 to a portion of the upper surface of the electrode plate 42 where the electrical insulating layer 24 was not formed. After taking out the electrodes in this manner, the solar cells 23 on the electrode plate 42 were sealed with a translucent silicon resin as the sealing material 29.
The electrode plate 42, the heat dissipation electrical insulating layer 41, and the support plate portion 11 a were fixed with an electrical insulating screw 27.

With this structure, the heat generated in the solar battery cell 23 is conducted to the electrode plate 42 through the back electrode and solder, and is diffused by the electrode plate 42 in the surface direction of the electrode plate 42, that is, toward the outer side of the solar battery cell 23. By dissipating heat to the outside air through the insulating layer 41 and the support plate portion 11a, good heat dissipation characteristics can be realized.
In the above structure, when the sunlight 13 of 850 W / m ² was actually condensed and applied to the solar battery cell 23, the temperature of the solar battery cell 23 could be suppressed to about 60 ° C.
In addition, when the entire back electrode of the solar battery cell 23 is fixed to a copper plate by soldering, the cell is stressed due to the difference in thermal expansion coefficient, and there is a concern that there may be a problem such as cell cracking or cell characteristic deterioration. As a result of conducting a thermal cycle test from the liquid nitrogen temperature (−about 195 ° C.) to 120 ° C. in the structure of No. 1, problems such as cell cracking and characteristic deterioration did not occur even in 30 cycles.

  In a concentrating solar power generation system, the amount of use of solar cell material is suppressed, that is, the smaller the size of the solar cell 23, the better, and studies are proceeding in the direction of reducing the external size of the solar cell and increasing the concentration factor. . For this reason, the problem of deterioration of the characteristics of the solar cells 23 and cracking due to the generation of stress due to the difference in thermal expansion coefficient between the solar cells 23 and the metal plate does not become a big problem. On the other hand, since the condensing magnification can be increased, improvement of heat dissipation characteristics is the most important issue, and the structure of the present invention is suitable for solving this problem.

It is sectional drawing of the concentrating solar cell module of this invention. It is a perspective view of the solar cell fixing | fixed part of this invention. It is an expanded sectional view of the solar cell fixing part of the present invention. It is a figure which shows the temperature characteristic of the compound solar cell used in the Example of this invention. It is the result (parameter dependence of the photovoltaic cell temperature) of the thermal radiation simulation which concerns on embodiment of this invention. It is a result (relationship of an electrode board thickness and a photovoltaic cell maximum temperature) of the thermal radiation simulation which concerns on embodiment of this invention. It is a result of heat dissipation simulation (embodiment size of electrode plate / solar cell size and solar cell maximum temperature) according to the embodiment of the present invention. It is the schematic which shows the conventional concentrating solar power generation system. It is a schematic sectional drawing which shows the conventional concentrating solar cell module.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Case 12 Fresnel lens 13 Sunlight 11a Support plate part 21a Metal foil 21b Wire bonding 22 Solar cell surface electrode 23 Solar cell 24 Electrical insulation layer 25 Front electrode lead wire 26 Back electrode lead wire 27 Electrical insulation screw 29 Sealing Fixing material 41 Heat dissipation electric insulation layer 42 Electrode plate 43 Solder

Claims (9)

A solar cell having electrodes on the front surface and the back surface, an electrode plate electrically connected to the back electrode of the solar cell by solder, and a support plate that supports the electrode plate through a heat dissipation electrical insulating layer A concentrating solar cell module,
The electrode plate constitutes a wiring member to the outside on the back electrode side of the solar battery, is larger than the size of the solar battery cell, the thickness of the electrode plate is t (mm), and the thermal conductivity of the electrode plate is When λ (W / K / m), λ × t is 160 or more and 2000 or less.   2. The concentrating solar cell module according to claim 1, wherein λ × t of the electrode plate is 400 or more and 1200 or less.   3. The concentrating solar cell module according to claim 1, wherein an outer size of the electrode plate is not less than 3 times and not more than 10 times an outer size of the solar battery cell.   4. The concentrating solar cell module according to claim 3, wherein an outer size of the electrode plate is not less than 6 times and not more than 9 times an outer size of the solar battery cell.   The concentrating solar cell module according to any one of claims 1 to 4, wherein the electrode plate is made of metal as a main material.   The concentrating solar cell module according to claim 5, wherein the electrode plate is mainly made of copper.   The concentrating solar cell module according to claim 6, wherein the electrode plate has a thickness of 1 mm to 3 mm.   8. An electrical insulating layer is formed on at least a part of the upper surface of the electrode plate, and a surface electrode side lead wiring of the solar battery cell is disposed on the electrical insulating layer. 2. The concentrating solar cell module according to item 1.   The concentrating solar cell module according to claim 8, wherein the electrical insulating layer is a resist mainly composed of an acrylic resin.

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