JP2003188399A - Solar cell module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a solar cell module that is chemically stable for a long time, prevents the reduction of the amount of incidence due to discoloration or the like, can maintain the same surface state without any dirt as a case where smooth glass is used, and at the same time has a glare-preventing function for preventing the projection of concentrated reflection light to neighboring buildings or the like. <P>SOLUTION: In the solar cell module, a transparent, electrically insulating surface protection member 4 is provided at the light reception surface side of a solar cell 3, and a specific oblique angle to the ground is provided corresponding to the intention of use. In this case, a plurality of grooves 6 that are formed along the direction of inclination are provided on the surface of the surface protection member 4, and at the same time rainwater flows toward a downstream direction of the inclination in the grooves 6. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solar cell module and a solar cell-equipped roof or a solar cell-equipped building equipped with the solar cell module. The present invention relates to a structure for preventing deterioration of power generation characteristics due to surface contamination.

[0002]

2. Description of the Related Art Thin-film solar cells are considered to be the mainstream of solar cells in the future because of their thinness, light weight, low manufacturing cost, and easy enlargement.
Demand is expanding for commercial use, which is attached to the roof and windows of buildings, and for general housing. Roof tiles with solar cells for general housing, and building materials with solar cells in which a solar cell module is integrated as a building material on the wall surface of a building have also been developed.

In recent years, research and development of a flexible type solar cell using a plastic film has been promoted, and by utilizing this flexibility, mass production becomes possible by a roll-to-roll system or a step roll system manufacturing method. There is.

As a thin-film solar cell module in which a plurality of solar cell elements are connected in series or in parallel, a solar cell formed on an electrically insulating film substrate is sealed with an electrically insulating protective material. It is known that a protective layer is provided on both the light-receiving surface side and the non-light-receiving surface side of a solar cell.

FIG. 5 and FIG. 6 show examples of typical structures of conventional solar cell modules and solar cell panels,
FIG. 5 is a side sectional view of the solar cell module, and FIG. 6 is a side sectional view of the solar cell panel in a state where the solar cell module is mounted on a frame having a U-shaped metal frame body.

In FIG. 5, a solar cell 21 has a plurality of solar cell elements connected in series or in parallel, and a light-receiving surface side of the surface protection member 22 such as a glass plate (thickness 3 mm) and a non-light-receiving surface. On the surface side, for example, a back surface protection member 30 made of aluminum foil having both surfaces adhered with ethylene monofluoride (trade name: Tedlar, manufactured by DuPont) is provided, and EVA (ethylene-acetic acid) is excellent in adhesive sealing property and inexpensive. It is heat-sealed by an adhesive resin sealing material 40 such as vinyl copolymer resin). As the EVA, for example, a thickness of 0.4 to
0.8 mm sheet EVA is used. This EVA
After the above members are laminated, a vacuum laminator is used to heat and pressurize at a temperature of about 120 ° C to 160 ° C to perform adhesive fixing, and then heat curing in a dryer at 130 ° C to 160 ° C. To be done. EVA protruding from the periphery of the glass plate is cut and removed.

In the solar cell 21, internal lead wires 50 and 60 are electrically connected to the plus (+) pole and the minus (-) pole of the solar cell 21. The internal lead wires 50 and 60 are, for example, back surface protection members. Connection terminal box 70 adhered and fixed to 30
In the inside of the connection terminal box 70, it is electrically connected to the core wires 90 and 100 of the cable 80 as external lead wires, and the solar cell module 110 is formed as a whole.

As the surface protection member 22, in addition to an inorganic material such as a glass plate, an organic material such as a transparent acrylic plate may be used. In addition, the back surface protection member 3
In addition to the above, 0 may be a single organic film such as a fluorine-based film, a composite material obtained by laminating an organic film and a metal foil, or a metal / inorganic material such as a metal plate or a glass plate.

FIG. 6 shows an example of a solar cell panel in which a solar cell module is mounted on a frame. In FIG.
The holding portion 1 in which the peripheral portion 13 of the solar cell module 110 has a frame body 14a of a U-shaped cross section of the metal frame 120.
4 is fixed and held by an adhesive sealing material 15 that is inserted inside and injected to fill the gap. Here, as the adhesive sealing material 15, an elastic elastic sealing material having adhesiveness such as butyl rubber having heat fluidity and silicone rubber which becomes solid after being liquid, is used, and the surface protection member 22 such as a glass plate or the frame 120. Absorbs the thermal expansion of
Suppresses water invasion.

FIG. 3 is a perspective view of a simplified solar cell module for convenience of explanation of the present invention. In FIG. 3, 1 is a back surface protection member, 2 is an adhesive resin sealing material for protecting the solar cell and joining with other members, 3 is the solar cell, 9
Indicates a surface protection member, and 5 indicates a frame for fixing the solar cell module.

By the way, a material that can transmit sunlight and has weather resistance is generally used for the surface protection member constituting the light receiving surface of the solar cell module. For example, a transparent glass plate. When used as the light receiving surface of the solar cell module, there is almost no problem in terms of the above-mentioned sunlight transmission and weather resistance, but when the surface of the glass is smooth, the sunlight incident on the light receiving surface It is a big problem that a part of the light is reflected and the reflected light is projected on a nearby building or house, which causes so-called light pollution.

To solve the above problems, various proposals have been made and patent applications have been filed. For example, Japanese Patent Laid-Open No. 2001-
Japanese Patent No. 189479 discloses that "a light scattering sheet having a complex uneven shape is provided on at least the incident surface side of a plate-shaped surface member on which the sunlight of a solar cell module is incident, or by using frosted glass for incidence. Part of the sunlight was diffusely reflected due to the complicated uneven shape of the surface, a method of preventing concentrated reflection on a nearby building is described, and also "as a method for producing the light-scattering sheet, Molding is performed by pressing a plate-shaped or roll-shaped mold heated to the molding temperature onto a transparent resin. "

Further, in Japanese Patent Laid-Open No. 2001-177130, "A contact angle to water is 7 on the incident surface side of a transparent substrate.
In a solar cell module having an antiglare film having good wettability of less than 5 °, the antiglare film contains particles of an organic material or an inorganic material and an organic material binder, and the organic material binder is an acrylic resin and fluorine. In addition to 100 parts by weight of the first component containing at least one of the base resins, 1 part by weight or more and 50 parts by weight of the second component which is a hydrolyzable silyl group-containing organosilicate and / or a condensate thereof. It is formed by applying the material contained in the range below to the glass surface by a method such as spraying. "

Further, Japanese Patent Application Laid-Open No. 11-298030 discloses that "the surface of a cover glass used for a solar cell on the light incident side has irregularities, and the tops of the irregularities are flattened to make the surface roughness of the cover glass rough. The maximum height Ry is 0.1
5 μm, and the arithmetic average roughness Ra is 0.01 to 0.3.
A cover glass for a solar cell having a size of μm ”is disclosed.

[0015]

The conventional solar cell module described above has the following problems. First, when using the light-scattering sheet described in JP 2001-189479 A, there are the following problems. The first problem is the chemical stability of the light-scattering sheet having an uneven structure on the surface. In order to achieve the useful life of the solar cell module, which is said to be at least 20 years, the light-scattering sheet itself must be chemically or mechanically stable within this period without causing any practical problems.

During the long-term use as described above, it is conceivable that the resin undergoes a chemical change under the influence of ultraviolet rays contained in sunlight and its mechanical strength and transparency are impaired. In particular, the light-scattering sheet on the incident side, which is directly exposed to the atmosphere, is exposed to more severe conditions, and is considered to be susceptible to the influence. However, in the disclosure examples of the above publications, the light-scattering sheet is described only as “transparent resin, etc.”, and its chemical composition is not mentioned, and the durability is 20 years or more in reality. It is considered difficult to select a resin having a certain value and maintain a desired function.

The second problem is the problem of adhesion of components such as sand and dust floating in the atmosphere that affect the incident amount of sunlight to the surface of the solar cell module. If the incident surface of the solar cell module is a smooth surface such as a transparent glass plate,
Even if sand or dust in the atmosphere temporarily adheres to the glass surface, once it rains, most of it is washed away from the surface of the solar cell module and settles in a practically unproblematic range. It is proved by the proof test of.

However, in this case, since the surface of the solar cell module is smooth, concentrated reflection of sunlight occurs on the surface of the solar cell module, which is taken up in the present invention, which causes trouble to nearby houses and the like. Will be called.

Therefore, in the disclosed example of the above publication, a resin sheet having a complicated uneven shape is arranged on at least the incident surface side of the plate-shaped surface member of the solar cell module, and a part of the incident sunlight is absorbed by the resin sheet. Diffuse reflection due to the uneven structure prevents intensive reflection on neighboring houses. However, since the anti-glare sheet has complicated irregularities, the surface area becomes larger than that of a smooth surface, and the presence of the recesses makes it easier for sand or dust to adhere to the surface.

Further, even if the surface is changed from a complicated uneven shape to an uneven shape having a wavy cross section in order to suppress the adhesion of components that affect the performance of the solar cell, the surface contamination is slightly improved. However, as long as a molded resin sheet is applied, it is considered that the surface will soon lose its smoothness and sand and dust will adhere due to the chemical action of ultraviolet rays in sunlight.

In the case of rain, if the surface is smooth, these adhering components can be washed away together with rainwater, and an incident amount within a range where there is no practical problem can be secured. On the surface, it is difficult for rainwater to flow smoothly over the surface.

FIG. 4 is a schematic diagram for explaining a situation in which sand or dust adheres to the surface of the solar cell module. As shown in FIG. 4, the sand or dust component 11 having a large specific gravity has a concave portion on the module surface. It is easy to accumulate in 10. When the rain stops and the surface becomes dry, the amount of incident light on the solar cell module decreases due to the influence of these components left in the recesses, and the performance deteriorates. It is a common experience in daily life that the sand and dust accumulated in the recesses become coagulated when once wet and then dried, and cannot be easily removed by subsequent rain and wind.

Further, the above-mentioned Japanese Patent Laid-Open No. 2001-177130.
Also in the method of providing an antiglare film having a good wettability with a contact angle of less than 75 ° with respect to water on the incident light side of a transparent substrate as described in JP-A-2001-18.
It is considered that the problem of the solar cell module described in Japanese Patent No. 9479, that is, the problem that the output of the solar cell module decreases due to chemical instability of the coating material and adhesion of sand or dust to the surface recess cannot be avoided. .

The above-mentioned Japanese Patent Laid-Open No. 2001-189479.
In the publication, instead of a light-scattering sheet made of resin, frosted glass is laminated with transparent glass, or an example of using frosted glass itself as a surface protection member is disclosed, but in this case, surface stains In the initial state, there is an essential problem that the amount of transmitted light is reduced as compared with transparent glass, and there is also a problem that sand and dust are likely to adhere to the surface of the solar cell module.

Further, even when the cover glass having the uneven surface on the light incident side and the top of the uneven surface described in JP-A No. 11-298030 is applied, the antireflection function is obtained. Even if it is obtained, the problem that the surface of the solar cell module is contaminated by the accumulation of sand or dust in the recess cannot be solved.

The present invention has been made to solve the above problems, and an object of the present invention is to be chemically stable for a long period of time and to prevent a decrease in incident amount due to discoloration or the like. It is an object of the present invention to provide a solar cell module having an anti-glare function that can maintain a surface state that is as clean as that when smooth glass is used and that does not project concentrated reflected light on a nearby building or the like.

[0027]

In order to solve the above-mentioned problems, in the present invention, a transparent electric insulating surface protecting member is provided on the light receiving surface side of the solar cell, and it is suitable for the ground and the purpose of use. In the solar cell module installed at a predetermined inclination angle, the surface protection member has a plurality of grooves formed on the surface thereof along the inclination direction, and the grooves are provided with rainwater. It is designed to flow in the groove in the downstream direction of the inclination (the invention of claim 1).

According to the above structure, a part of the sunlight incident on the surface of the solar cell module is diffusely reflected, and the concentrated reflection of sunlight, which is a problem in the conventional solar cell module having a flat surface, is caused. It is possible to prevent light damage to adjacent buildings due to.

When the module is attached, the groove provided on the surface of the solar cell module allows the rainwater to flow at least in the groove to the downstream side of the inclination due to the inclination of the module. Components that deteriorate the performance of the solar cell, such as sand and dust adhering to the surface including the groove of the module, will be washed away by rain as much as the conventional solar cell module surface with a flat surface,
It is possible to prevent the performance of the solar cell module from being deteriorated due to the reduction of the incident amount due to the accumulation of the components such as sand and dust in the recesses of the surface, which has been a problem with the surface having the uneven surface.

That is, by applying the present invention, both antiglare and prevention of reduction in power generation efficiency of the solar cell due to surface contamination can be achieved at the same time.

As an embodiment of the invention according to claim 1,
The inventions of claims 2 to 4 below are preferable. That is, in the solar cell module according to claim 1, the surface protection member is a glass plate from the viewpoint of durability (claim 2
Invention).

Further, in the solar cell module according to claim 1 or 2, the inclination path of each of the plurality of grooves formed along the inclination direction is a straight line or a curved line (claim 3). invention). If the solar cell module is installed so as to be inclined so that rainwater flows at least in the groove toward the downstream side of the inclination due to the inclination, the groove does not necessarily have to be a straight line and may be a curved line. .

Further, in the solar cell module according to any one of claims 1 to 3, the cross section of the cross section perpendicular to the path of the groove is substantially rectangular, triangular, semicircular or corrugated. Either of them or a combination of the above shapes (the invention of claim 4). The shape of the cross section is not particularly limited as long as sand or dust in the atmosphere or rain adheres to the groove surface as long as it is easily washed away by rain or the like.

[0034]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to FIGS.

FIG. 1 is a perspective view of a solar cell module according to an embodiment of the present invention, and FIG. 2 is a perspective view of an embodiment different from FIG. 1 and 2, the same members as the members of the solar cell module shown in FIG. 3 are designated by the same reference numerals, and detailed description thereof will be omitted.

In the embodiment shown in FIG. 1, the backside protective member 1 is a steel plate whose surface is electrically insulated with ETFE (ethylene tetrafluoride copolymer resin). It may be an aluminum plate, glass, or other composite material as long as it is electrically insulated and has a mechanical strength capable of supporting the solar cell module. In addition, the adhesive resin encapsulating material 2 is EVA (trade name EVASAFEWG142 manufactured by Bridgestone Corporation).
5) was used to coat both sides of the solar cell 3 with a laminator. As the solar cell 3, an amorphous solar cell formed on a polyimide film was used, but the type of solar cell is not limited to the above.

In the present embodiment, the template glass plate is used as the surface protection member 4. The groove 6 on the surface of the glass plate was formed by using a mold having a substantially semicircular groove cross-section when the glass plate was manufactured and which was periodically repeated. The back surface protection member 1, the EVA-encapsulated solar cell 3, and the glass plate 4 having a semicircular cross-section groove 6 on the surface were fixed to a frame 5 using a filler (not shown) to obtain a solar cell module. The groove 6 provided on the glass plate is provided in a direction parallel to the tilt direction of the tilted solar cell module.

FIG. 2 shows an embodiment in which the cross-sectional shape of the groove is different from that of the solar cell module, and the groove shape is a substantially rectangular shape as indicated by a part number 8. The configuration other than the groove 8 is shown in FIG.
It is equivalent to the embodiment shown in.

The dimensions of the grooves shown in FIGS. 1 and 2 will be described below. For example, for a glass plate having a thickness of 3 mm, the preferable groove width is about 1 to 5 mm, the groove depth is about 0.5 to 1.0 mm, and the groove pitch is the same as the groove width.

Although a glass plate having good durability was used as the surface protection member 4 in the above embodiment, a transparent acrylic or polycarbonate template is used when a slight decrease in durability can be tolerated. You can also Further, the cross-sectional shape of the groove is not limited to the substantially semicircular shape or the rectangular shape as in the above-described embodiment, but may be a triangular shape, a corrugated shape, or a combination of the above-described shapes.

[0041]

According to the present invention, as described above, the solar cell has a transparent electric insulating surface protection member on the light-receiving surface side and is installed with a predetermined inclination angle according to the ground and the purpose of use. In the solar cell module according to the present invention, the surface protection member has a plurality of grooves formed on the surface thereof along the inclination direction, and the grooves are provided so that rainwater is inclined downstream in the grooves. Since it is designed to flow in a directional direction, it is chemically stable for a long period of time, there is no decrease in the incident amount due to discoloration, etc., and the surface condition is as clean as when using smooth glass. It is possible to provide a solar cell module that can be maintained and has an anti-glare function that does not project concentrated reflected light on a nearby building or the like.

[Brief description of drawings]

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

FIG. 2 is a perspective view of a solar cell module according to another embodiment different from FIG.

FIG. 3 is a perspective view showing a simplified conventional solar cell module.

FIG. 4 is a schematic diagram illustrating a situation in which sand and dust adhere to the surface of the solar cell module.

FIG. 5 is a side sectional view of a schematic configuration showing an example of a conventional solar cell module.

FIG. 6 is a side sectional view of a schematic configuration of a solar cell module in which the module of FIG. 5 is attached to a frame.

[Explanation of symbols]

1: Back surface protection member, 2: Adhesive resin sealing material, 3: Solar cell, 4: Surface protection member, 5: Frame, 6, 8: Groove.

Claims (4)

[Claims] 1. A solar cell module comprising a transparent, electrically insulating surface protection member on the light-receiving surface side of a solar cell, the solar cell module being installed at a predetermined inclination angle according to the ground and the purpose of use. The member has a plurality of grooves formed on the surface thereof along the inclination direction, and the grooves allow rainwater to flow in the grooves in a downstream direction of the inclination. Solar cell module. 2. The solar cell module according to claim 1, wherein the surface protection member is a glass plate. 3. The solar cell module according to claim 1, wherein each of the plurality of grooves formed along the tilt direction has a straight line or a curved line in the tilt direction. Battery module. 4. The solar cell module according to claim 1, wherein the cross section of the groove at a right angle to the path of the groove is substantially rectangular, triangular, semicircular, or corrugated. Or a combination of the above shapes, a solar cell module.