JP2009032852A - Solar-battery module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a solar battery module having a sufficient heat dispersion property and including a heat radiation means of light weight and low cost. <P>SOLUTION: The solar battery module includes a translucent cover plate, a solar battery cell having a non light receiving surface and a light receiving surface which faces a rear surface of the translucent cover plate, and a heat radiation plate having a rear surface which faces the non light receiving surface of the solar battery cell. Heat radiation plate is made from the material containing graphite and is roughened as a heat radiation fin. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a solar cell module, and more particularly to a solar cell module provided with a heat dissipation plate that suppresses temperature rise.

The power generation efficiency of the silicon crystal solar cell decreases as the temperature rises. Particularly affected is the voltage (which can be represented by the open-circuit voltage (Voc)), which decreases at a rate of about −0.4% / ° C. in the case of a polycrystalline cell. As a result, the maximum output (Pm) is also about −0.5% / ° C. In midsummer, the cell temperature is said to rise to nearly 70-80 ° C, and if the output at 25 ° C in the standard condition specified in JIS is 100%, the output decline is 78% at 70 ° C, which cannot be overlooked. Occur. For this reason, the total amount of power generation in summer with a large amount of solar radiation and long sunshine hours is not much different from that in winter when the sunshine hours are short, and the largest amount of total power generation in the year is in spring and autumn. Also, for example, when dead leaves fall on a module in which many cells are connected in series, and only one cell is covered, all the power of that module is concentrated in that cell, and that cell generates heat. become. Such a phenomenon is called a hot spot, but the module can be damaged by heat. Again, heat dissipation is an effective means.
Conventional examples of heat dissipation means include a fin provided on the back surface of the solar cell module, a hybrid module that cools solar cells with a heat medium such as water and uses hot water at the same time, a heat radiation plate, and a back surface of the module. There exist what fills the fluid as a heat medium, what cools with water cooling, air cooling, a heat-radiation sheet, a heat pipe, etc. (for example, refer patent documents 1-8).

JP 11-36540 A Japanese Patent Laid-Open No. 10-62017 Japanese Patent Laid-Open No. 2005-123452 Japanese Patent Laid-Open No. 11-354819 JP 2005-18352 A JP 2002-170974 A JP 2005-136236 A JP-A-9-186353

  However, since the conventional heat dissipation means increases the cost of the module, the actual solar cell module does not take any measures for heat dissipation. In the present invention, a solar cell module can be provided with a technology that can sufficiently provide heat dissipation and is lightweight and inexpensive.

The present invention relates to the solar cell module according to the following (1) to (7).
(1) Translucent cover plate;
A solar cell having a non-light-receiving surface and a light-receiving surface facing the back surface of the translucent cover plate; and
A heat sink having a back surface facing the non-light-receiving surface of the solar cell;
In a solar cell module having
A solar cell module, characterized in that the heat radiating plate is made of a material containing graphite and has been subjected to uneven processing as a heat radiating fin.

  (2) The solar cell module according to (1), wherein the material containing graphite includes graphite powder and a resin component.

  (3) The solar cell module according to (1) or (2), wherein the surface of the heat radiating plate is subjected to uneven processing.

  (4) The solar cell module according to any one of (1) to (3), wherein an insulating back surface material is attached to the back surface of the heat radiating plate.

  (5) The translucent cover plate is a translucent substrate, and the solar cells are sealed with a filler and sandwiched between the back surface of the translucent substrate and the back surface of the heat dissipation plate. The solar cell module according to any one of (1) to (4).

  (6) The solar cell module according to any one of (1) to (4), wherein the translucent cover plate is a condensing lens that condenses sunlight on a light receiving surface of the solar cell.

  (7) The solar cell module according to (6), wherein the solar cell is sealed with a filler.

  The heat dissipation plate of the material containing graphite which has been subjected to unevenness processing as the heat dissipating fin of the present invention is applied to the solar cell module to alleviate the decrease in power generation efficiency due to the increase in solar cell temperature.

The solar cell module of the present invention is
Translucent cover plate;
A solar cell having a non-light-receiving surface and a light-receiving surface facing the back surface of the translucent cover plate; and
A heat sink having a back surface facing the non-light-receiving surface of the solar cell;
In a solar cell module having
The heat radiating plate is made of a material containing graphite, and is provided with uneven processing as a heat radiating fin.

  The heat sink can be made using a mixture of graphite powder and resin as a raw material, and the fin structure can be easily obtained by press molding, etc. Is preferable. As graphite powder, natural graphite such as scale natural graphite produced in China, Madagascar, Ukraine, Brazil, etc., scale natural graphite produced in Sri Lanka, soil-like natural graphite produced in Korea, China, Korea, Mexico, etc. And artificially produced artificial graphite in powder form, expanded graphite and powder obtained by sheeting and pulverizing expanded graphite. In particular, it is preferable to use natural graphite powder from the viewpoint of cost reduction and expanded graphite powder from the viewpoint of improving thermal conductivity. The shape of these graphite powders is not particularly limited, such as a spherical shape, a lump shape, a scale piece, a dendritic shape, etc., but the average particle size is preferably 5 to 500 μm, more preferably 10 to 300 μm. If the average particle size is less than 5 μm, the moldability of the material containing graphite tends to be poor, and if it exceeds 500 μm, it tends to be difficult to produce a dense molded body.

As the resin mixed with the graphite powder, a thermoplastic resin, a thermosetting resin, or the like can be used.
Examples of the thermoplastic resin include polyethylene, polypropylene, polymethylpentene, polybutene, crystalline polybutadiene polystyrene, polybutadiene, styrene butadiene resin, polyvinyl chloride, polyvinyl acetate, polyvinylidene chloride, ethylene vinyl acetate copolymer (EVA, AS, ABS, ionomer, AAS, ACS), polymethyl methacrylate (acrylic), polytetrafluoroethylene, ethylene polytetrafluoroethylene copolymer, polyacetal (polyoxymethylene), polyamide, polycarbonate, polyphenylene ether, polyethylene terephthalate, poly Butylene terephthalate, polyarylate (U polymer), polystyrene, polyethersulfone, polyimide, polyamideimide, polyphenyle Sulfide, polyoxybenzoyl, polyether ether ketone, polyether imide, other liquid polyester.

  Examples of the thermosetting resin include phenol resin, amino resin (urea resin, melamine resin, benzoguanamine resin), unsaturated polyester resin, diallyl phthalate resin, alkyd resin, epoxy resin, urethane resin, silicon resin, and the like. It is done.

  As the resin, it is preferable to use a thermosetting resin, in particular, a phenol resin or an epoxy resin, because it is excellent in handleability and weather resistance.

  The mixing ratio of the graphite powder and the resin is preferably 30 to 95 parts by weight, more preferably 40 to 90 parts by weight, per 100 parts by weight of the total amount of the graphite powder and the resin.

  There is no particular limitation on the manufacturing method of the heat sink, but for example, a material containing graphite such as a mixture of graphite powder and resin is stirred, mixed, kneaded, rolled with a kneader, a reiki machine, a Henschel mixer, a planetary mixer, a roll machine, etc. The obtained mixture is a heat sink made of a material containing graphite, for example, graphite powder and a resin component, by a known plastic molding method such as injection molding, extrusion molding, press molding, etc. It can be formed by forming into a heat sink having a shape in which unevenness is formed at the site.

  In addition, the uneven structure serves as a heat radiating fin, and this structure can take a known structure as a fin shape. The shape of the convex part that becomes the fin includes a straight fin, a curved fin or a bent fin (the cross section perpendicular to the longitudinal direction of the fin is a square, rectangle, triangle, trapezoid, other curved surface), an annular fin (radial Examples of the cross section include a rectangle, a triangle, a trapezoid, and other curved surfaces), a protruding fin (a cylinder, a cone, a polygonal pyramid, and the like).

  Although there is no restriction | limiting in particular in the thickness and uneven | corrugated size of a heat sink, Usually, it is preferable that the thickness of the flat plate part containing the base part of a convex part is 0.5-10 mm, and it is more preferable that it is 1-5 mm. .

  As the translucent cover plate, a flat translucent substrate may be used, or a condensing lens for condensing sunlight on the light receiving surface of the solar battery cell may be used. Examples of the material for these translucent cover plates include transparent glass, synthetic resins such as transparent acrylic resin, and transparent polycarbonate resin. The thickness of the translucent substrate is generally 1 to 10 mm, preferably 2 to 5 mm, but is not particularly limited.

Examples of the solar cell include, but are not limited to, a single crystal silicon substrate, a polycrystalline silicon substrate, an amorphous silicon substrate, and the like. The size of the solar battery cell is not particularly limited, and a thickness of 160 to 350 μm is usually used.
Although only one solar battery cell may be used for one solar battery module, usually, two or more solar battery cells that are electrically connected are arranged in a plane and used.

  The solar cell is preferably sealed with a filler having heat resistance and insulating properties. A light-transmitting filler is used at least on the light-receiving surface side of the solar battery cell. The filler used on the non-light-receiving surface side of the solar battery cell may be one that does not have translucency, such as being colored as necessary. As a specific example of the filler, for example, ethylene-vinyl acetate copolymer (EVA) is generally used, but is not limited thereto.

  When the translucent cover plate is a translucent substrate, solar cells sealed with a filler are usually opposed to the back surface of the translucent substrate with the light receiving surface facing the back surface of the heat sink. With this arrangement, the light-transmitting substrate is sandwiched between the rear surface of the light-transmitting substrate and the rear surface of the heat sink. When the translucent cover plate is a condensing lens, normally, the solar cells sealed with a filler are attached to the back surface of the heat sink with the non-light receiving surface facing the back surface of the heat sink, The condensing lens is disposed at a position where sunlight is condensed on the light receiving surface with the back surface thereof facing the light receiving surface of the solar battery cell.

Hereinafter, one embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a partially exploded view showing the configuration of the solar cell module of one embodiment of the present invention, and FIG. 2 is a partial cross-sectional view of the solar cell module manufactured with the configuration of FIG. In this embodiment, a cover glass (tempered glass) having a thickness of 3 mm was used as the translucent substrate 1. The solar battery cell 3 is disposed with the light receiving surface 31 facing the back surface of the translucent substrate 1 and the non-light receiving surface 32 facing the back surface of the heat radiating plate 6 made of graphite material. The heat sink 6 has a large number of irregularities on its surface. A large number of solar cells 3 (only one solar cell is shown in FIG. 1) are arranged in a plane, and a plurality of solar cells 3 connected to the upper and lower surfaces (negative electrode and positive electrode) of the solar cells 3. The tab wires 4 are connected in series. The light receiving surface side filler 21 is disposed on the light receiving surface 31 of the solar battery cell 3, and the non-light receiving surface side filler 22 is disposed on the non-light receiving surface 32. In this embodiment, sheet-like EVA was used for each filler. On the back surface of the heat radiating plate 6, that is, the surface facing the non-light-receiving surface 32 of the solar battery cell 3, the back material 5 is disposed. The back material 5 is used as necessary to prevent moisture from entering the solar cell module, and an insulating sheet or plate-like material is used, and the material is not particularly limited. For example, a single layer or two or more layers of synthetic resin sheets, synthetic resin sheet plates, etc., such as a DuPont Tedlar film (polyvinylidene fluoride, PVF) and a PET laminate film, can be used. For example, an adhesive is used for adhering the back surface material 5 to the back surface of the heat radiating plate 6, and the above filler may be used as an adhesive and may be used when the solar cell module is manufactured.
Although there is no restriction | limiting in particular in the manufacturing method of the solar cell module of this invention, Each member is laminated | stacked by the structure of said aspect, and the solar cell module of the aspect shown in FIG. 2 is low-cost by heat-pressing under pressure reduction. Can be manufactured with good productivity. The light-receiving surface-side filler 21 and the non-light-receiving surface-side filler 22 are fused to each other by heating and pressurization at the time of manufacture, and the solar cell 3 is sealed as an integral filler 2. The solar cell 3 sealed with the filler 2 is sandwiched between the back surface side of the translucent substrate 1 and the back surface to which the back material 5 of the heat sink 6 is attached.

  In the present invention, a graphite material having good thermal conductivity and emissivity is used as the material of the heat sink, and the unevenness as the heat sink fins (ribs) for cooling is formed, so that an excellent heat dissipation effect is exhibited and power generation efficiency is improved. The temperature of the solar battery cell can be lowered to such an extent that it is sufficiently improved.

  Hereinafter, the present invention will be described more specifically with reference to examples of the present invention and comparative examples thereof, but the present invention is not limited to these examples.

[Example 1]
Graphite powder (crushed expanded graphite sheet (HGR-207) manufactured by Hitachi Chemical Co., Ltd., average particle size: 200 μm) 30 parts by weight and resin (resol phenol resin, manufactured by Hitachi Chemical Co., Ltd.) 70 wt. The parts were mixed by a pressure kneader, heated and pressed at a temperature of 170 ° C. and a pressure of 10 MPa for 10 minutes, and press-molded to produce a 200 mm × 200 mm heat radiation plate having a plurality of irregularities on one side. Here, the unevenness on the surface of the heat sink has a stripe shape as shown in FIG. 5, and the symbols W, w, D, and d in the figure are 1 mm, 1 mm, 1 mm, and 0.5 mm, respectively. .
The solar cell module was produced by the following procedure. An EVA sheet (thickness: 0.6 mm) as a light receiving surface side filler is laid on a 200 mm × 200 mm × 3 mm (thickness) solar cell cover glass as a light-transmitting substrate, and electricity can be taken out of the module on the sheet. A single solar cell (polycrystalline silicon, 150 mm × 150 mm × 0.25 mm) connected in this manner is placed, and further, an EVA sheet (thickness: 0.4 mm) as a non-light-receiving surface side filler, and a back material A tedlar film (thickness: 38 μm) as an adhesive, an EVA sheet (thickness: 0.4 mm) as an adhesive, and a heat dissipation plate made of a material containing the above graphite and having irregularities on its outer surface are arranged in this order, and a vacuum laminator is used. Module sealed. The sealing conditions were a temperature of 150 ° C., a vacuum of 10 minutes, and a pressure of 15 minutes (pressure: 98 kPa). About the obtained solar cell module, when back surface temperature and open circuit voltage (Voc) were evaluated outdoors, they were as shown in FIGS. 3 and 4, respectively. The maximum temperature difference and the maximum open circuit voltage difference are listed in Table 1.

[Comparative Example 1]
A sealed solar cell module was prepared in the same manner as in Example 1 except that a PET sheet (thickness: 85 μm) was laid instead of the heat dissipation plate made of a material containing graphite and having an uneven surface. The obtained solar cell module was evaluated in the same manner as in Example 1.

表１中、「温度」は、実施例及び比較例で最も差がでるときのそれぞれの温度を、「Voc］は、実施例及び比較例で最も差がでるときのそれぞれの開放電圧（Voc）を意味する。

In Table 1, “Temperature” is the temperature at which the difference is most significant in the example and the comparative example, and “Voc” is the open circuit voltage (Voc) at which the difference is greatest in the example and the comparative example. Means.

The partial structure figure (exploded view) of the solar cell module which is 1 aspect of this invention. The fragmentary sectional view of the solar cell module shown in FIG. The graph (back surface temperature) which shows the solar cell module outdoor evaluation result of Example 1 and Comparative Example 1. FIG. The graph which shows the solar cell module outdoor evaluation result of Example 1 and Comparative Example 1 (open circuit voltage). The uneven | corrugated cross-sectional shape of the heat sink used in Example 1. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Translucent board | substrate 2 Filler 21 Light-receiving surface side filler 22 Non-light-receiving surface side filler 3 Solar cell 31 Light-receiving surface 32 Non-light-receiving surface 4 Tab wire 5 Back surface material 6 Heat sink (it consists of a material containing graphite on the surface) Heat sink with irregularities.)

Claims (7)

Translucent cover plate;
A solar cell having a non-light-receiving surface and a light-receiving surface facing the back surface of the translucent cover plate; and
A heat sink having a back surface facing the non-light-receiving surface of the solar cell;
A solar cell module comprising: a solar cell module, wherein the heat radiating plate is made of a material containing graphite and is subjected to uneven processing as a heat radiating fin.   The solar cell module according to claim 1, wherein the material containing graphite contains graphite powder and a resin component.   The solar cell module according to claim 1, wherein the surface of the heat radiating plate is processed to be uneven.   The solar cell module according to any one of claims 1 to 3, wherein an insulating back surface material is attached to a back surface of the heat radiating plate.   The translucent cover plate is a translucent substrate, and the solar cells are sealed and sandwiched between a back surface of the translucent substrate and a back surface of the heat sink. The solar cell module in any one of 1-4.   The solar cell module according to claim 1, wherein the translucent cover plate is a condensing lens that condenses sunlight on a light receiving surface of the solar cell.   The solar cell module according to claim 6, wherein the solar cell is sealed with a filler.

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