JP2001053320A - Solar battery module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a highly reliable inexpensive solar battery module, which can secure durability and waterproofing property for a long period, even when the module is set up at such a location where a large temperature difference occurs between daytime and nighttime, and in addition, can prevent scattering of glass pieces when the module is broken. SOLUTION: A solar battery module is constituted by interposing a sealing layer between the surface of a surface glass substrate 1, on which a photoelectric conversion section 6 is formed and a rear-surface cover 2 in the peripheral edge section of the module. The sealing layer is constituted of a primary sealing layer composed of an elastic rubber spacer 3, and adhesive butyl rubber 4 packed in the spaces between the spacer 3 and substrate 1 and between the spacer 3 and cover 2 and a secondary sealing layer, composed of an adhesive resin sealant 5 and provided on the outer periphery of the primary sealing layer. It is preferable to provide a recessed or a projecting section, which holds the spacer 3 on the peripheral edge section of the cover 2, and in addition, to stick an adhesive rubber layer to the photoelectric conversion section 6 and the surface of the substrate 1 in the surrounding of the section 6.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a structure of a solar cell module.

[0002]

2. Description of the Related Art A sealed structure of a solar cell module has been proposed and implemented, for example, in Japanese Patent Application Laid-Open No. 4-56173. In this method, the front glass substrate on which the photoelectric conversion unit is formed and the back cover substrate are bonded and integrated via a primary seal layer and a secondary seal layer formed on the outer periphery thereof, and the photoelectric conversion unit is formed on the front glass substrate and the seal layer. , And a back cover. The primary seal layer is made of, for example, a substance containing butyl rubber as a main component, and the secondary seal layer is made of, for example, a silicone resin, a urethane resin, an epoxy resin, or the like. In this case, the primary role of the primary seal layer is to suppress the permeation of water vapor, and the primary role of the secondary seal layer is to bond the front glass substrate to the back cover.

FIG. 6 shows a cross-sectional structure of this solar cell module. The back cover 25 includes a metal plate 26 as a substrate and a pair of output terminals 27, and the metal plate 26 and the output terminals 27 are insulated by an insulating packing 28. A butyl rubber 31 serving as a primary seal layer and an adhesive resin serving as a secondary seal layer are provided on the peripheral surface of the surface glass substrate 29 on the side where the photoelectric conversion unit 30 is formed and on the peripheral edge facing the inner surface of the metal plate 26. A sealing layer 32 is provided to seal the solar cell module. Lead wires 33 are connected to each of the positive and negative output terminals 27, and these lead wires 33 are connected to the photoelectric conversion unit 3.
It is connected to the positive and negative electrode portions 34 on the 0 side. The other surface of the front glass substrate 29 is covered with a transparent fluororesin film 35 for preventing scattering when the front glass substrate 29 is broken by an external force such as an impact.

[0004] The butyl rubber of the primary seal layer used in the above-mentioned proposed embodiment is, for example, a solid butyl rubber having an adhesive property such as a hot melt type. In such a structure in which the soft but not sufficiently elastic adhesive butyl rubber is sandwiched between the front glass substrate and the back cover, if a small load is applied before or before the step of forming the secondary seal layer. In addition, the primary seal layer is easily deformed flat and thin. As a result, it is not possible to ensure a sufficient adhesion area of the sealant and the distance between the front and back substrates when forming the secondary seal layer on the outside, and secure long-term reliability, improve the accuracy of the thickness dimension, and ensure sufficient electrical insulation resistance. Was difficult.

Further, since the front and back substrates of the solar cell module are made of different materials, their thermal expansion coefficients are different. Especially, when the solar cell module is installed in a place where the temperature difference between day and night is large, such as a roof surface, the thermal expansion coefficient is high. The metal back cover has high expansion and contraction, which causes the solar cell module to expand or shrink, causing the soft adhesive butyl rubber to move inward, exposing the end of the photoelectric conversion unit to outside the butyl rubber. However, there is a problem that the sealing performance is reduced. In the conventional solar cell module, a scattering prevention film was attached to the surface of the front glass substrate as a measure to prevent scattering when the front glass substrate was broken. Expensive materials had to be used.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and a first object of the present invention is to improve the durability and reliability of a seal to maintain long-term waterproofness. Another object of the present invention is to provide a solar cell module that can be optimally installed in a place having a large temperature difference between day and night. A second object is to improve the accuracy of the outer dimensions, particularly the thickness, of the solar cell module, and to ensure the installation on a roof surface or the like. The third objective is to provide a low-cost solar cell module that does not have to worry about glass fragments being scattered even if a flying object hits the surface glass substrate of the installed solar cell module in the event of a rain or a typhoon. It is to be.

[0007]

In order to solve the above-mentioned problems, a solar cell module according to the present invention comprises: a surface glass substrate having a photoelectric conversion portion formed on one surface; A solar cell module configured with a sealing layer interposed at a peripheral portion of a portion facing the side, wherein the sealing layer is formed from a primary sealing layer and a secondary sealing layer, and the primary sealing layer is A rubber spacer having elasticity, and a butyl rubber having adhesiveness filled in a gap between a joint between the rubber spacer and the front glass substrate and a gap between a joint between the rubber spacer and the back cover, The secondary seal layer is formed on an outer peripheral portion of the primary seal layer, and is made of an adhesive resin.

As described above, by interposing the elastic rubber spacer between the front glass substrate and the back cover, even if the back cover is pressed onto the front glass substrate via the primary seal layer at the time of assembling, the primary seal can be obtained. The layers do not deform. As a result, the facing gap between the front glass substrate and the back cover can be reliably and uniformly secured, and a sufficient bonding area of the secondary seal layer can be secured. In addition, even if the thermal expansion coefficients of the front and back members of the solar cell module are different, since the sealing layer material has elasticity, it can absorb the difference in thermal expansion coefficient. Can also be sealed. further,
Since a sufficient distance between the front glass substrate and the back cover can be ensured, the dimensional accuracy of the solar cell module is increased, and a sufficient insulation resistance is ensured, so that leakage of photo-generated electricity can be reliably prevented.

[0009]

DETAILED DESCRIPTION OF THE INVENTION As described above, the seal layer of the present invention has a low water vapor transmission rate, a primary seal layer having both elasticity and tackiness, and an adhesive secondary seal layer provided outside the primary seal layer. A double-layered structure is formed with the layer, and in particular, the structure of the inner primary seal layer is fixed by sticking the elastic rubber spacer of the core portion and the rubber spacer to the front glass substrate and the back cover. The most characteristic feature is that the adhesive butyl rubber layer has a double structure.

In the above-mentioned conventional solar cell module, the elasticity which does not cause plastic deformation even when a load is applied during an assembling operation or an installation operation, and a property of adhering to the front glass substrate and the back cover are sufficiently obtained. There has been a demand for a material for the primary seal layer which also serves as a primary seal layer. However, in reality, it is difficult to find such a material, and as a result, it has been necessary to use an adhesive butyl rubber having poor elasticity, and the above-mentioned problems could not be solved.

According to the present invention, the primary seal layer is formed from two members sharing roles, apart from the conventional idea that the elasticity and adhesiveness required for the primary seal layer are satisfied by one member. This has been solved. That is, without plastic deformation against the load,
Moreover, a rubber spacer as an elastic member capable of absorbing a difference in thermal expansion coefficient between the front glass substrate and the back cover, and an adhesive as a member for adhering and fixing the rubber spacer and the front glass substrate and between the back cover. A primary seal layer is formed from butyl rubber.

Hereinafter, the function and effect of the present invention will be described in more detail. First, by using an elastic rubber spacer for the primary seal layer, even if the back cover is pressed onto the front glass substrate via the primary seal layer during assembly, the primary seal layer does not spread, and the bonding distance of the secondary seal layer And the distance between the front glass substrate and the back cover can be reliably and uniformly secured. Further, even if the thermal expansion coefficients of the front and back members of the solar cell module are different, the difference in the thermal expansion coefficient can be absorbed because the sealing layer material has elasticity. As a result, even when the solar cell module is installed on a roof surface or a building window having a large temperature difference between day and night, deformation such as warpage can be prevented. Furthermore, since the rubber spacer is insulative and the distance between the front glass substrate and the back cover can be ensured, the reliability of the electrical insulation is further improved, and the danger of leakage of photo-generated electricity is reduced. In addition, the distance between the front glass substrate and the back cover can be made constant, which facilitates fitting of the solar cell module to the frame material and attachment to the roof panel.

The material of the rubber spacer used in the present invention is preferably a material that has high elasticity over a wide temperature range and low moisture permeability. In general, a rubber is crosslinked by a vulcanization reaction to form a network structure, whereby slippage between molecules is stopped, and the rubber exhibits high elasticity and tensile strength in a wide temperature range. Therefore, in the present invention, various types of vulcanized rubber processed into a predetermined shape such as a frame shape can be widely used as a rubber spacer. In particular, among the above, it is preferable to use vulcanized butyl rubber or chlorinated butyl rubber having low moisture permeability. On the other hand, the vulcanized butyl rubber and chlorinated butyl rubber generally have poor tackiness, and are unsuitable for use as the tacky butyl rubber in the present invention.

In the present invention, the butyl rubber used as the adhesive butyl rubber to be filled in the joint between the rubber spacer and the front glass substrate and between the back cover is a rubber that has not been vulcanized. It is preferable to use a material having an additive to impart tackiness. These adhesive butyl rubbers include a hot melt type and a curable liquid type.

Further, in the solar cell module according to the present invention, it is preferable that a concave portion or a convex portion for holding the rubber spacer is formed on an inner peripheral portion of the back cover. A concave or convex portion corresponding to the shape of the end of the rubber spacer is formed along the peripheral edge of the back cover, and the end of the rubber spacer is fitted and fixed to this, so that the temperature cycle between day and night can be performed. Therefore, it is possible to more reliably prevent the primary seal layer from moving inside the module, and to secure long-term reliability of the seal.

Further, in the solar cell module of the present invention, a mesh-like or sheet-like adhesive rubber layer is adhered over the surface of the photoelectric conversion portion and the surface glass substrate surface around the formation portion of the photoelectric conversion portion. Is preferred. As the material of the adhesive rubber layer, various unvulcanized rubbers can be generally used, and for example, hot melt type butyl rubber or silicone rubber is preferably used. With this, even if the surface glass substrate breaks for some reason,
The broken glass fragments can be prevented from scattering, and safety can be ensured. Also, unlike the conventional case, it is not necessary to attach an expensive film for preventing scattering on the surface glass substrate, so that an inexpensive solar cell module can be manufactured.

Next, an example of an embodiment of a solar cell module according to the present invention will be specifically described.

Embodiment 1 FIG. 1 is a schematic sectional view of a solar cell module constructed according to the present invention. In FIG. 1, a front glass substrate 1 and a back cover 2 are formed of a seal layer at a peripheral portion, specifically, a primary seal layer composed of a rubber spacer 3 and an adhesive butyl rubber 4 and a secondary seal layer composed of an adhesive sealant 5. , Are arranged substantially in parallel. On the inner surface of the front glass substrate 1, a photoelectric conversion unit 6 is formed. The front glass substrate 1 is made of, for example, borosilicate glass. Each lead wire 8 connected to each of the positive and negative electrode portions 7 of the photoelectric conversion portion is connected to the back cover 2.
Is drawn out to the outside through a hole having a diameter of about 8 mm provided in a metal substrate constituting the terminal board 9 and is connected to the terminal block 9. The hole of the back cover 2 is the sealant 1 filled in the terminal cover 18.
Sealed by 0. Electricity generated by the output cable 11 connected to the terminal block 9 is output.
The outer surface of the front glass substrate 1 is covered with a transparent fluororesin film 14.

When the solar cell module thus manufactured is installed on a roof as a power supply unit for a house,
An aluminum frame is mounted around its periphery and mounted on the roof via a gantry, or as part of the roofing material, directly mounted on the roof panel by a mounting frame.

The photoelectric conversion section 6 includes a tin oxide film, a cadmium sulfide (CdS) film,
It has a structure in which a cadmium telluride (CdTe) film, a carbon electrode, and a silver electrode are sequentially laminated. Normal,
These photoelectric conversion units are divided into a plurality of single cells and formed on the surface glass substrate 1, and these single cells are connected in series or in series / parallel to form a submodule. The photoelectric conversion unit 6 is not limited to the above-mentioned CdS / CdTe system, and may be, for example, an amorphous silicon solar cell having an amorphous silicon semiconductor layer formed thereon, or another thin film compound semiconductor solar cell.

The rubber spacer 3 is molded in a frame shape, and the cross section thereof is formed with a groove 15 on each of the surfaces joined to the front glass substrate 1 and the back cover 2 as shown in FIG. Adhesive butyl rubber 4 is applied to the groove 15, and the front glass substrate 1, the back cover 2, and the rubber spacer 3 are adhered and integrated with the adhesive butyl rubber 4. Usually, the thickness of the rubber spacer 3 is preferably in the range of 3 mm to 7 mm, and is set to 4.5 mm in the present embodiment. If it is less than 3 mm, the electrical insulation between the photoelectric conversion unit 6 and the back cover 2 may be insufficient, and
When the distance exceeds m, handling such as carrying the solar cell module becomes inconvenient. In addition, as the sealant 5, an adhesive such as a silicone resin, a urethane resin, an epoxy resin, or a polysulfide resin can be used.

<Second Embodiment> In order to securely hold the rubber spacer 3 at a predetermined position between the front glass substrate 1 and the back cover 2, a frame-shaped recess 16 is formed on the inner peripheral edge of the back cover 2. An example in which is provided will be described. As shown in FIG. 3, by providing two frame-shaped protrusions 12 in parallel along the periphery of the back cover 2, a frame-shaped recess 16 is formed between the two protrusions 12. You. Adhesive butyl rubber 4 is applied to the recess 16 in advance, and the rubber spacer 3 is fitted into the recess 16 so that the rubber spacer 3 can be reliably arranged at a predetermined position. The rubber spacer 3
As shown in FIG. 4, the cross-sectional shape is formed with two convex portions 12 and concave and convex portions 17 having a shape corresponding to the shape of the concave portion 16 formed by the two convex portions. Thereby, the rubber spacer 3 can be stably held at a predetermined position. By filling the outside of the rubber spacer 3 of the primary seal layer formed as described above with the adhesive sealant 5, the rubber spacer 3
The surface glass substrate 1 and the back cover 2 are more firmly bonded to each other, and the penetration of water vapor into the solar cell module is almost completely blocked. In the above case, a method of providing a frame-shaped concave portion 16 at the peripheral edge of the inner surface of the back cover 2 is adopted. However, a frame-shaped convex portion is formed at the peripheral edge of the inner surface of the back cover 2 and fitted thereto. The same effect as in the above method can also be obtained by using a rubber spacer provided with a concave portion having the following shape.

<< Embodiment 3 >> An example in which an adhesive rubber layer is adhered over the surface of the photoelectric conversion portion and the surface glass substrate around the photoelectric conversion portion will be described. As shown in FIG. 5, a mesh-like or sheet-like adhesive rubber layer 13 is arranged on the photoelectric conversion unit 6 inside the solar cell module, and the surface is removed except for the peripheral portion where the seal layer is adhered or adhered. Adhesion is applied over almost the entire surface of the glass substrate 1. For the adhesive rubber layer 13, hot melt type butyl rubber is used, and is applied by injection using a hot melt applicator. As an application method, you may apply by screen printing. With this configuration, even if the front glass substrate 1 is broken for some reason, it can be prevented from being scattered, safety can be ensured, and a conventional expensive anti-scatter film can be provided on the front glass substrate 1 as in the prior art. There is no need to stick it on

[0024]

As described above, according to the present invention, the primary seal layer has a double structure of an elastic rubber spacer and an adhesive butyl rubber layer, so that the long-term durability and electrical insulation of the solar cell module can be improved. In addition, the waterproof property can be maintained, and the external dimension accuracy can be increased, and thermal deformation can be prevented. further,
By forming a concave portion or a convex portion for holding the rubber spacer inside the back cover, the rubber spacer can always be held at the same position, so that long-term durability and waterproofness can be maintained. Further, by sticking the adhesive rubber layer from the photoelectric conversion portion to the peripheral portion of the inner surface of the front glass substrate, scattering of glass fragments when the front glass substrate is broken can be prevented.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of a solar cell module according to an embodiment of the present invention.

FIG. 2 is a sectional view of a rubber spacer used for the solar cell module.

FIG. 3 is a schematic half sectional view of a solar cell module according to another embodiment of the present invention.

FIG. 4 is a sectional view of a rubber spacer used in the solar cell module.

FIG. 5 is a plan view of an embodiment in which an adhesive rubber layer is adhered from the photoelectric conversion portion to the inner surface of the peripheral surface glass substrate according to the present invention.

FIG. 6 is a schematic sectional view of a conventional solar cell module.

[Explanation of symbols]

 1, 29 Front glass substrate 2, 25 Back cover 3 Rubber spacer 4 Adhesive butyl rubber 5, 10 Sealant 6, 30 Photoelectric conversion part 7, 34 Electrode part 8, 33 Lead wire 9 Terminal block 11 Output cable 12 Convex part 13 Adhesion Rubber layer 14, 35 Fluororesin film 15 Groove 16 Depression 17 Roughness 18 Terminal cover 26 Metal plate 27 Output terminal 28 Insulation packing 31 Butyl rubber 32 Adhesive resin

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Junji Nakajima 1-1, Matsushita-cho, Moriguchi-shi, Osaka Matsushita Battery Industrial Co., Ltd. (72) Inventor Norio Nakajima 1-1-1, Matsushita-cho, Moriguchi-shi, Osaka Matsushita Battery (72) Kuniyoshi Omura, 1-1, Matsushita-cho, Moriguchi-shi, Osaka F-term (reference) in Matsushita Battery Industry Co., Ltd. 5F051 BA17 EA01 EA17 EA18 EA20 GA03 JA02 JA04 JA05

Claims (3)

[Claims] 1. A solar cell comprising a front surface glass substrate having a photoelectric conversion portion formed on one surface and a seal layer interposed at a peripheral portion of a portion where the photoelectric conversion portion formation surface and the inner surface side of the back cover face each other. A battery module, wherein the sealing layer comprises:
The primary seal layer is formed of a primary seal layer and a secondary seal layer, and the primary seal layer has a resilient rubber spacer, a gap at a joint between the rubber spacer and the front glass substrate, and the rubber spacer and the back cover. A solar cell module, comprising: butyl rubber having an adhesive property filled in a gap between the joints of (1) and (2), wherein the secondary seal layer is formed on an outer peripheral portion of the primary seal layer and is made of an adhesive resin. 2. The solar cell module according to claim 1, wherein a concave portion or a convex portion for holding the rubber spacer is provided at a peripheral portion on the inner surface side of the back cover. 3. The method according to claim 1, wherein a mesh-like or sheet-like adhesive rubber layer is adhered over the surface of the photoelectric conversion portion and the surface of the surface glass substrate around the formation portion of the photoelectric conversion portion. Solar cell module.