JP2006278709A - Solar battery module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a solar battery module capable of improving the dissipation efficiency of heat generated in a solar battery cells, while maintaining electrical insulation. <P>SOLUTION: In the solar battery module, a solar battery element 5 sandwiched by a light-receiving surface side sealing material 2 and a rear-surface side sealing material 5 is arranged between a translucent light-receiving surface member 1 and a rear-surface sheet 6. The sealing material 5 has a large number of through-holes 8 formed thereon, a thermoconductive paste 9 consisting of insulating particles having a thermoconductive rate larger than that of the rear surface side sealing member, and an adhesive resin is filled into the through holes 8. The thermoconductive paste 9 contacts the rear-surface sheet 6. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a solar cell module, and more particularly to a solar cell module with improved heat dissipation.

Solar cell elements are often manufactured using a single crystal silicon substrate or a polycrystalline silicon substrate. For this reason, the solar cell element is vulnerable to physical impact, and when the solar cell is installed outdoors, it is necessary to protect it from rain. Moreover, since the electrical output generated by one solar cell element is small, it is necessary to connect a plurality of solar cell elements in series and parallel so that a practical electrical output can be taken out. For this reason, a solar cell module is usually manufactured by connecting a plurality of solar cell elements and encapsulating with a sealing material mainly composed of a translucent light-receiving surface member and ethylene vinyl acetate copolymer (EVA). It has been broken.

  In a solar cell module installed outdoors, the temperature of the solar cell module rises to about 40 to 50 ° C. due to heat generated by the operation of the solar cell element even at an outside air temperature of 20 ° C. during power generation. As described above, when the temperature of the solar cell module increases, the power generation efficiency decreases due to the temperature characteristics of the solar cell element.

  Furthermore, when one solar cell element in the plurality of solar cell elements of the solar cell module that is generating power is in the shadow of the solar cell module and power generation becomes insufficient, this solar cell element becomes a resistance. At this time, a potential difference of the product of the resistance value and the flowing current is generated between both electrodes of the solar cell element. That is, a reverse bias voltage is applied to the solar cell element, and this element generates heat. Such a situation is called a hot spot. If the hot spot phenomenon occurs and the temperature of the solar cell element continues to rise, in the worst case, the solar cell element is destroyed, and thereafter, a predetermined electric output cannot be obtained from the solar cell module.

  FIG. 4 is a diagram showing the configuration of a conventional solar cell module. 21 is a translucent light receiving surface member, 22 is a light receiving surface side sealing material, 23 is a connection tab, 24 is a solar cell element, 25 is a back surface side sealing material, and 26 is a back sheet. The translucent light receiving surface member 21 is often made of white plate tempered glass having a thickness of about 3 to 5 mm. The solar cell element 24 is made of single crystal silicon, a polycrystalline silicon substrate, or the like having a thickness of about 0.2 mm, and the approximate size is, for example, about 150 mm square for a polycrystalline silicon solar cell. At the time of manufacturing the solar cell module, a solar cell element connected in series and parallel with the connection tab 23 such as an electrode of the solar cell element and copper foil is used. As described above, many of the sealing materials 22 and 25 mainly include polyvinyl butyral (PVB) in addition to ethylene vinyl acetate copolymer (EVA). The back sheet 26 is made of a weather-resistant fluorine-based resin that sandwiches an aluminum foil so as not to transmit moisture.

In order to cool the solar cell module when the temperature rise or hot spot of the solar cell module as described above occurs, the solar cell module is provided with a film with a high heat emissivity on the back surface side of the solar cell module or the sun. It has been devised to provide a ventilation opening in a module frame disposed around the battery module. (See Patent Document 1)
Further, a solar cell module has been devised in which a sheet material having a high thermal conductivity is disposed between the solar cell element and the back surface side sealing material. (See Patent Document 2)
JP-A-6-181333 JP 2004-31455 A

  However, as described above, in the method of providing the back surface sheet 26 of the solar cell module with a film having a concavo-convex surface and a high thermal emissivity, the thermal conductivity of the back side sealing material 25 such as EVA is poor. Heat is trapped inside, the temperature tends to rise, and the heat dissipation effect is insufficient.

  In addition, in the case where the ventilation holes are provided in the module frame disposed around the solar cell module, it is considered that the strength of the solar cell module is affected, and further, the effect is insufficient in the no-wind state. It is done.

  Further, as described above, in the method in which the sheet material having a large thermal conductivity is disposed between the solar cell element 24 and the back surface side sealing material 22, the heat conduction of the back surface side sealing material 25 such as EVA is poor. It is conceivable that heat is trapped inside the solar cell module, the temperature tends to rise, and the heat dissipation effect becomes insufficient.

  The present invention has been made in view of such problems, and its purpose is to improve the thermal conductivity inside the solar cell module and to reduce the power generation efficiency by suppressing the temperature rise of the solar cell module during photovoltaic power generation. While preventing, it is in preventing the destruction of a solar cell element by suppressing the temperature rise of the solar cell element when a hot spot generate | occur | produces.

In order to achieve the above object, in a solar cell module in which a solar cell element sandwiched between a light receiving surface side sealing material and a back surface side sealing material is disposed between a light transmitting light receiving surface member and a back sheet,
A plurality of through holes are formed in the back side sealing material, and in the through holes, insulating particles having a thermal conductivity larger than that of the back side sealing material and an adhesive resin having the same composition as the back side sealing material It is characterized by being filled with a heat conductive paste composed of the above and being brought into contact with the back sheet.

  In the said solar cell module, it is desirable that the said back surface sheet contains the ceramic and / or metal sheet.

  In the solar cell module, the particles having a large thermal conductivity are preferably alumina or zirconia.

  According to the solar cell module according to claim 1, the solar cell module in which the solar cell element sandwiched between the light-receiving surface side sealing material and the back surface side sealing material is disposed between the translucent light-receiving surface member and the back surface sheet. And forming a through hole in the back side sealing material, electrically insulating in the through hole, and having larger thermal conductivity than the back side sealing material, and the back side sealing material The heat conductive paste having a high particle filling rate composed of the adhesive resin having the same composition is filled, and the heat conductive paste is in contact with the back sheet, so that the heat generated in the solar cell element can be quickly transferred to the sun. It is possible to transmit to the battery module back sheet and dissipate heat from the back sheet.

  In the invention according to claim 2, when the back sheet is provided with a ceramic and / or metal sheet, the heat generated in the solar cell element is transferred to the back sheet with a heat conductive paste, and thus has a higher thermal conductivity than the resin sheet. , Can quickly dissipate heat to the outside air.

  In the invention according to claim 3, if the particles contained in the heat conductive paste are particles having a high thermal conductivity such as alumina or zirconia, the heat dissipation rate is fast and the insulation is excellent, so that the withstand voltage during the reliability test is high. Even good results.

  Further, even when local heat is generated due to a hot spot or the like, the diffusion of heat is accelerated and the solar cell element can be prevented from being destroyed. Furthermore, the light receiving surface side of the solar cell module tends to increase in temperature compared to the back surface side due to light absorption, etc., but in the present invention, heat radiation from the back surface side does not have any effect on the light receiving surface side, and it is efficient. The temperature rise of the solar cell module can be suppressed uniformly.

  Hereinafter, the solar cell module of the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a view showing the structure of a solar cell module according to the present invention. In FIG. 1, 1 is a translucent light receiving surface member, 2 is a light receiving surface side sealing material, 3 is a solar cell element, 4 is a connection tab, and 5 is a back surface side in which a large number of through holes are filled with a heat conductive paste. Sealing material 6 is a back sheet.

  As the translucent light receiving surface member 1, a transparent substrate made of glass or polycarbonate resin is used. As for the glass plate, white plate glass, tempered glass, double tempered glass, heat ray reflective glass, etc. are used, but generally white plate tempered glass with a thickness of about 3 mm to 5 mm is used to increase the light collecting property. There is also an embossed back surface. On the other hand, when a substrate made of a synthetic resin such as polycarbonate resin is used, a substrate having a thickness of about 5 mm is often used.

  The light-receiving surface side sealing material 2 is mainly composed of polyvinyl butyral (PVB) or olefin as well as a transparent ethylene vinyl acetate copolymer (EVA) excellent in weather resistance, heat resistance, water resistance and light resistance. Is used.

  The solar cell element 3 is made of, for example, single crystal silicon or polycrystalline silicon having a thickness of about 0.3 to 0.4 mm and a size of about 150 mm square. Inside the solar cell element 3 is formed a PN junction (not shown) in which a P layer containing a large amount of P-type impurities such as boron and an N layer containing a large amount of N-type impurities such as phosphorus are in contact. Further, electrodes (not shown) are formed on the light receiving surface side surface and the back surface side surface of the solar cell element 3 by screen printing or the like, and the surface of the electrode is easy to attach the protection and connection wiring 6 to. In order to do so, it is solder coated over almost the entire surface.

  When a solar cell module is manufactured, a plurality of solar cell elements 3 are connected by connecting, by soldering or the like, connection tabs 4 such as copper foil having a width of about 1 to 7 mm, which are subjected to solder plating or the like, on the electrodes of the solar cell element 3. Are connected in series or in parallel so that a predetermined electrical output is generated from the solar cell module.

  FIG. 2 is a perspective view of the back surface side sealing material 5 according to the present invention, and FIG. 3 is an enlarged cross-sectional view of the back surface side sealing material 5 in which a large number of through holes are filled with a thermal conductive paste. It is.

  2 and 3, 7 is a back side sealing material sheet, 8 is a through hole, 9 is a heat conductive paste, 10 is an insulating particle having a large heat conductivity, and 11 is an adhesive resin.

  The back surface side sealing material sheet 7 which concerns on this invention has ethylene vinyl acetate copolymer (EVA), polyvinyl butyral (PVB), an olefin, etc. as a main component. Among these, EVA is suitable in consideration of the cost of the solar cell module and long-term stability. However, for example, the thermal conductivity of EVA is as low as 0.2 W / mK. Therefore, in the back surface side sealing material sheet 7 according to the present invention, a large number of through holes 8 are formed in the back side sealing material sheet 7. Thermal conductivity composed of insulating particles 10 having insulating properties and thermal conductivity larger than that of the material of the back side sealing material sheet 7 and an adhesive resin having the same composition as the back side sealing material 7 The functional paste 9 is filled. Thereby, the back surface side sealing material 5 is completed. And this heat conductive paste 9 is arrange | positioned so that the back surface sheet 6 may be contacted.

Such a back surface side sealing material sheet 7 has a through hole formed by punching with a metal pin or the like. The diameter of the hole is about 1 mm to 5 mm, and the number thereof is about 2500 to 10000 / m ² . If the diameter of the hole is 1 mm or less, the heat conductive paste is difficult to enter the hole, and if it is 5 mm or more, the adhesion to the solar cell element 3 is weak. If the number is less than 2500 / m ² , the conduction distance of the heat of the solar cell element 3 to the heat conductive paste 9 becomes long and the heat dissipation effect becomes weak, and if it is more than 10,000 / m ² , the solar cell element 3. And the back surface side sealing material 5 become weak, and the heat dissipation effect in long-term use becomes weak. Further, the heat conductive paste 9 is filled into the large number of through holes 8 by press-fitting with a squeegee specification printer, and then dried in a drying furnace at about 50 to 80 ° C. for about 30 minutes, and fixed to the through holes 8.

  As the insulating particles 10 having a high thermal conductivity, particles such as ceramics such as alumina and zirconia having a diameter of about 0.01 mm to 0.1 mm, and metals such as aluminum and stainless steel having good thermal conductivity and light weight can be used. In view of the thermal conductivity, the insulation property of the solar cell module and the withstand voltage performance, alumina (thermal conductivity 21 W / mK), zirconia (thermal conductivity 2.5 W / mK) and the like are optimal.

  In addition, the thermal conductive paste 9 is mixed and stirred with the insulating resin 10 having a large thermal conductivity in the adhesive resin 11 by about 0.01 to 3 with respect to EVA1 in a weight ratio so that it can be easily press-fitted with a printer. In addition, it is adjusted to about 300 to 1000 poise depending on the solvent.

  A large number of such through-holes 8 were formed, and filled therein with a thermally conductive paste 9 composed of insulating particles 10 having a large thermal conductivity and an adhesive resin 11 having the same composition as the back surface side sealing material sheet 7. Thus, it is possible to secure a sufficiently strong adhesion without dropping the adhesion between the back surface side filler 5 and the solar cell element over a wide area. If the adhesion is high, there will be no deviation in adhesion after long-term use of the thermal conductive paste and the solar cell element. In addition, unlike the molded product sheet, the heat conductive paste 9 does not need to maintain its own shape. Therefore, the resin content can be reduced and the filling rate of particles having high heat conductivity can be increased, and the contact rate between particles can be increased. As a result, the thermal conductivity becomes better.

  In addition, the back sheet 6 according to the present invention uses a thin fluorine-based resin having weather resistance in which an aluminum foil is sandwiched so as not to pass moisture. In order to further improve heat dissipation, the back sheet 6 is made of ceramic and Alternatively, a metal sheet is used. High-purity alumina and high-purity zirconia that have good thermal conductivity and good moisture resistance are suitable for the ceramic. As the metal, a light aluminum plate or a stainless steel material having a good thermal conductivity is optimal. Moreover, the effect of heat dissipation is high even in a composite of metal and ceramic. The thickness when using a ceramic or metal sheet is 20 μm to 100 μm, for example, and the heat dissipation is good. Furthermore, in order to improve heat dissipation, the surface of the outer surface of the back sheet 6 may be roughened by machining or the like to form irregularities of about 0.05 to 0.1 mm.

The solar cell module according to the present invention is manufactured as follows.
As shown in FIG. 1, the translucent light-receiving surface member 1, the light-receiving surface side sealing material 2, the solar cell element 3, the back surface side sealing material 5 in which a large number of through holes are filled with a heat conductive paste, and the back sheet 6 are formed. Sequentially stack and superimpose, set in a device called a laminator, pressurize while heating and pressing for 15 to 60 minutes at a temperature of about 100 to 200 ° C. under reduced pressure of about 50 to 150 Pa and pressurizing while expelling bubbles Thus, the light receiving surface side sealing material 2, the back surface side sealing material 5 and the heat conductive paste 9 are cross-linked and integrated to produce a solar cell panel.

  Next, a module frame (not shown) is attached to the four sides of the integrated solar cell panel. This module frame is usually made by extruding aluminum in consideration of the strength and cost required for the solar cell module, and alumite treatment or clear coating is applied to the surface.

  Furthermore, a solar cell module is completed by attaching a terminal box (not shown) for connecting the solar cell element to an external circuit on the back side of the solar cell panel with an adhesive.

  Thus, in the solar cell module in which the solar cell element sandwiched between the light-receiving surface side sealing material 2 and the back surface-side sealing material 5 is disposed between the translucent light-receiving surface member 1 and the back surface sheet 6, A large number of through holes are formed in the stopper, and the same composition as that of the insulating particles 10 and the back side sealing material sheet 7 which are electrically insulating in the through holes and have a higher thermal conductivity than the back side sealing material The heat conductive paste 9 composed of the adhesive resin 11 is filled, and the heat conductive paste 9 is in contact with the back sheet 6, so that heat generated by the current generated by the solar cell element 3 can be quickly removed from the sun. This can be transmitted to the back side of the battery module, thereby suppressing an increase in temperature of the solar cell element 3 and preventing a decrease in power generation efficiency of the solar cell module.

  Further, the back sheet 6 uses a ceramic and / or metal sheet to improve the thermal conductivity, and further uses the heat conductive paste 9 containing alumina or zirconia particles, so that the adhesiveness or filling property of EVA or the like can be obtained. It is possible to improve the thermal conductivity without losing the value, and it can be promptly transmitted to the back surface.

  In addition, this invention is not limited to the said embodiment, Many corrections and changes can be added within the scope of the present invention. For example, the solar cell element is not limited to a crystalline solar cell such as a single crystal or polycrystalline silicon, and can be applied to a thin film solar cell.

It is sectional drawing which shows the structure of the solar cell module which concerns on this invention. It is a perspective view of the back surface side sealing material which concerns on this invention. It is an expanded sectional view of the back side filling material with which the heat conductive paste was filled in many through-holes of this invention. It is sectional drawing which shows the structure of the conventional solar cell module.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1; Translucent light-receiving surface member 2; Light-receiving surface side sealing material 3; Solar cell element 4; Connection tab 5; Back surface side sealing material 6 with which many through holes were filled with heat conductive paste; A back surface side sealing material sheet 8; a through hole 9; a thermal conductive paste 10; an insulating particle 11; an adhesive resin 21; a translucent light receiving surface member 22; a light receiving surface side sealing material 23; Element 25; Back side sealing material 26; Back side sheet

Claims (3)

In the solar cell module in which the solar cell element sandwiched between the light-receiving surface side sealing material and the back surface-side sealing material is disposed between the translucent light-receiving surface member and the back surface sheet,
A plurality of through holes are formed in the back side sealing material, and in the through holes, insulating particles having a thermal conductivity larger than that of the back side sealing material and an adhesive resin having the same composition as the back side sealing material A solar cell module, which is filled with a heat conductive paste comprising: The solar cell module according to claim 1, wherein the back sheet includes a ceramic and / or metal sheet. The solar cell module according to claim 1, wherein the insulating particles having a high thermal conductivity are alumina or zirconia.

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