JP3482370B2 - Solar cell module - Google Patents

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, which is particularly low in equipment cost, prevents light reflection and adds color harmony to the wall or roof to stabilize the power generation performance of the module for a long period of time. Sustainable solar cell module.

[0002]

2. Description of the Related Art In recent years, a solar cell module has been attracting attention as a clean energy source that does not cause pollution such as exhaust gas and radiation from the viewpoint of global environment protection. In these solar cell modules, silicon solar cells are generally used because the materials used have little effect on environmental protection, the energy conversion rate is high, and the power generation characteristics are stable. As such a silicon solar cell, for example, a single crystal silicon solar cell obtained by forming an n-type diffusion layer on the surface of a single crystal silicon substrate, forming an electrode, and then forming an antireflection film is well known. Has been.

[0003]

In the above single crystal silicon solar cell, the use of a single crystal silicon substrate has a drawback that the cost becomes high. Therefore, it has been proposed to use a low-cost heterogeneous substrate instead of the single crystal silicon substrate, and form a thin film of, for example, Si on it. However, when Si is deposited to a required thickness, the coefficient of thermal expansion greatly differs from that of the substrate, so that the substrate is warped, the yield is deteriorated, and the electrical characteristics are further deteriorated. As described above, various proposals for substituting the substrate have been made. However, in addition to the complicated structure in manufacturing, there is a disadvantage that the energy conversion rate is inevitably reduced as compared with the single crystal silicon solar cell. In addition to the reduction of equipment cost and manufacturing cost, its improvement is strongly desired.

Further, the solar cell module is installed outdoors, such as on the roof of a building, but in recent years suppression of light pollution due to diffused reflection has been a problem, or a decrease in light transmittance in response to that problem has become a problem. There is. In addition, it is difficult to accumulate rainwater and accumulate dust during use due to outdoor exposure, especially for solar cell modules that use a resin film as the outermost surface coating material and adhere to the surface during use. Although the accumulated dirt is removed to some extent, the degree of dirt removal due to natural conditions is inferior to that of glass, and rainwater retention and dirt easily adhere or accumulate due to the natural environment such as rain, snow and wind. However, the transparency of the surface coating material is lowered, the incident light reaching the photovoltaic element is lowered, and the photovoltaic power is lowered.

When a resin film is used as the outermost surface coating material, since the surface is smooth, light incident on the smooth surface at an angle close to parallel is totally reflected when the critical angle is exceeded, and the solar cell Since light does not enter the photovoltaic element, sufficient electromotive force cannot be generated. Also, when installing on the rooftop or wall surface of the roof,
Depending on the angle of the solar cell module, the reflected light may reach other houses or the like, which may cause a problem that people are dazzled and uncomfortable. In addition, wrinkles may occur on the surface due to repeated thermal expansion and thermal contraction of the covering material due to long-term outdoor exposure, which impairs the visual appearance. In addition, while reducing the decrease in light transmittance due to coloring as much as possible, there is little accumulation of dust etc. exposed to wind and rain, and the wall or roof of the building is colored or patterned to beautify the appearance of the building and design by color. It is desired to achieve a desired color harmony in order to achieve the desired color and decorative effect.

In order to solve such a drawback, for example, in Japanese Unexamined Patent Publication No. 9-191115, the light incident side surface of a photovoltaic element is in contact with the transparent organic polymer resin layer and the outermost surface on the outside thereof. In a solar cell module coated with two or more coating materials of a transparent surface protection film layer, a plurality of irregularities are formed on the surface of the coating material, and the pitch, height, groove length, and wire diameter of the irregularities are formed. Has been disclosed.
Further, in Japanese Unexamined Patent Publication No. 9-148603, a wheel-shaped gusset blade grindstone that swings a blade having a substantially V-shaped or U-shaped cross section on the ground surface has a substantially V-shaped or U-shaped surface. A solar cell including a substrate having concave and convex grooves is disclosed. Further, in Japanese Unexamined Patent Publication No. 9-102625, manufacturing of a solar cell element in which a semiconductor substrate is carried into a dry etching apparatus and a mask forming gas and an etching gas are simultaneously introduced into the apparatus to form minute uneven portions I have a suggestion on how to do it.

However, in the above-mentioned Japanese Patent Laid-Open No. 9-191115, the light-incident surface of the photovoltaic element is composed of a transparent organic polymer resin layer and two or more layers of a transparent surface protective film in contact with the transparent organic polymer layer and the outermost surface thereof. It is a structure covered with the coating material of
Although there is little direct light reflected from the surface, wrinkles are less likely to occur, and dirt can easily be removed.However, the transparent organic polymer resin layer impregnated with the fibrous inorganic compound on the light incident side of the photovoltaic element and the outermost layer in contact with it Since the covering material is composed of at least two or more transparent surface protective film layers on the surface, the structure is complicated and the material and manufacturing cost are increased. Further, in Japanese Unexamined Patent Publication No. 9-148603, the groove processing for reducing the light reflectance of the substrate is processing using a wide multi-blade grindstone having many blades.
A machine tool for grinding a substrate is required, and there is a problem that cost is inevitable unless processing for forming regular grooves and mass productivity are ensured. Furthermore, JP-A-9-1
According to Japanese Patent Laid-Open No. 02625, even though the manufacturing process can be simplified and the entire surface of the semiconductor can be uniformly etched, the manufacturing apparatus cost is high and the flow rate control of the used gas is required.

In order to solve the above-mentioned problems, the applicant of the present invention, in Japanese Patent Application No. 264822, 1997, screened a transparent float glass with a ceramic ink on the surface thereof.
A translucent substrate on which uneven bulges are formed by a printing method, and the uneven pitch and the height of the unevenness between the unevenness are formed in a desired uniform manner and regularly, and on the back surface in contact with the substrate. A conductive substrate provided with a plating layer to be a photovoltaic element,
Furthermore, a solar cell module is proposed, which is formed on the back surface with an insulating protective layer made of a back surface coating material.

However, as a result of studying the above proposed solar cell module, it is desirable to further prevent reflection pollution of light due to diffused reflection, and to minimize reduction in light transmittance due to coloring. Attention was paid to improvements such as beautification of the appearance of the building and design by color, decorative effect, and configuration of a solar cell module in which dust and the like are less accumulated due to wind and rain.

[0010]

The present invention has been made as a result of extensive studies in order to solve the above problems. (1) The transparent substrate is a transparent float manufacturing method or a roller.
A convex bulge portion is formed on the surface of the transparent glass plate by the manufacturing method by a screen printing method using ceramics ink, and the convex pitch and the height of the convex portion between the convex bulge portions are set to desired values. It has a substantially uniform structure and is regularly formed. In addition, the convex bulge is screen-printed to guide the flow of rainwater, dust, etc., in addition to beautifying design by combining stripes, checks, dot shapes or patterns, and pattern colors. A guide groove for facilitating removal is formed, and the convex bulge portion has a plurality of convex bulge portions, and the pitch between the convex bulge portions is at least 50 μm to 5000 μm, and the height of the convex portion is high. Is 10 μm to 100 μm, preferably 30 μm to 80 μm
Is formed in a desired setting range. (2) In the present invention, the surface coloring layer is layered on the entire circumferential surface of the convex bulge using a colored ceramics ink. (3) On the surface in contact with the translucent substrate, a conductive substrate provided with a plating layer serving as a photovoltaic element for efficiently collecting current is formed. (4) In addition, since the back surface maintains electrical insulation between the conductive substrate of the photovoltaic element and the outside, sufficient electrical insulation can be ensured, and long-term durability is excellent and thermal expansion or contraction is possible. In this configuration, a back surface coating material composed of an insulating protective layer capable of withstanding the above is provided. Further, a convex bulge portion is formed on the back surface side of the translucent substrate by using a ceramic ink.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The solar cell module of the present invention comprises:
Based on the above-described configuration, the following configuration modes are included, and the remarkable operation is achieved thereby.

The light-transmitting substrate used in the present invention is a plate-like body which is made of transparent or semi-transparent glass having at least light-transmitting property and which is formed by a transparent float manufacturing method or a roller manufacturing method. A colorless transparent glass plate, a colored transparent glass plate, a synthetic resin plate, or the like can be used if necessary. Further, it is required to have excellent light transmittance, hardness to withstand flying sand and hail, and strength against wind pressure, and a thickness of 3 to 4 mm is suitable.

The surface of the translucent substrate on the light incident surface side is
A convex bulge portion is formed by a screen printing method using ceramics ink. The convex pitch and the height of the convex portions between the convex bulge portions are approximately evenly and regularly set to a desired setting. It has a structure that is formed into. Further, the convex bulge is formed by a screen printing method in any one selected from stripe, check, dot shape, pattern and pattern. The translucent substrate has a plurality of uneven bulges, and at least the pitch between the convex bulges is 5 or less.
0 μm to 5000 μm, and the height of the convex portion is 10
Although it can be formed in a desired setting range of 100 μm, preferably 30 μm to 80 μm, by selecting and combining any shape of the screen mesh and stripe, check, and dot, which satisfies the above range,
For example, usually 300 mesh or less, appropriately 80 to 20
By using a 0 mesh screen, it is possible to form a convex bulge that matches a desired setting range.

Further, the light-transmissive substrate satisfies the condition of being optically transparent, and is not only light-transmissive but also adheres, accumulates, and is weather-resistant on the light-incident surface side during long-term outdoor exposure. It is necessary to meet the requirements of heat resistance, moisture resistance, fire resistance to fire, and flame retardancy. In particular, in the case of a translucent substrate formed with a plurality of convex bulges in the present invention, the effect of reducing surface reflection due to the presence of the convex bulges can be expected, on the other hand, in the case of long-term outdoor use, It is desired to prevent adhesion of dirt, prevention of accumulation, and ease of dirt removal, as well as suppressing defects in appearance. Therefore, in the present invention, it is possible to use a multi-functional surface coating material that prevents stains on the light-receiving surface due to long-term outdoor exposure conditions or that is easily removed even if stains adhere. For example, it is possible to use a ceramics ink in which powder particles of tourmaline ore that exert an action of forming an electric field of negative static electricity are kneaded, and to have a configuration capable of exhibiting such a stain prevention function. Specifically, by containing at least 5 to 15% by weight of tourmaline ore having an average particle size of 0.1 μm to 0.5 mm, dirt is prevented and adhered dirt is also removed due to natural conditions such as wind and snow, hail. It can be configured easily.

Further, in the present invention, when the convex bulging portion is formed by the screen printing method, a slip, a check,
Along with the appearance design or beautification consisting of dot shapes, patterns, and combinations of pattern-like colors, the protrusions are fixed to facilitate the removal and removal of rainwater and dust in a natural environment. A guide groove is provided in the surface coating material in which water or fine dust is inclined.

Due to the above-mentioned configuration of the transparent substrate, the required light transmittance is ensured, and the directly reflected light on the surface is reduced to improve the light collection rate and the reflectance of the light receiving surface, Even when used for a long period of time, the guide groove is provided so that rainwater can be easily guided and the accumulation of dust and the like is reduced to prevent a decrease in photoelectric conversion efficiency of the solar cell module.

In the present invention, it is a matter of course that the translucent substrate satisfies the condition that it is optically transparent. However, if necessary, the plurality of convex bulges are exposed to the outdoors such as wind and snow and hail. It is also possible to form a convex bulge portion on the back surface side of the translucent substrate, which is not the light incident surface side, by using a ceramic ink in the same manner.

Next, on the surface in contact with the transparent substrate, a conductive substrate provided with a plating layer serving as a photovoltaic element for collecting current efficiently is formed. In terms of management, the manufacturing is extremely simple and the power generation performance of the module can be stably maintained. The plating layer is formed as a plating layer to be a photovoltaic element on the back surface in contact with the translucent substrate, and this electrode is formed by a vacuum deposition method, a sputtering method, a spray method, or a conventional method which has been widely adopted. It can be formed using a pressure CVD method or another suitable method. As a material of the plating layer, a transparent metal oxide having good electric conductivity such as fluorine-containing copper oxide, antimony-containing tin oxide, and tin-containing indium oxide can be used.

Further, a back surface coating material made of an insulating protective layer is formed on the back surface of the conductive and conductive substrate. The coating material is necessary for maintaining electrical insulation, and the material is sufficient. It is desirable that it can ensure excellent electrical insulation, has excellent long-term durability, withstands thermal expansion and contraction, and has flexibility, and polyamide, polyethylene terephthalate, polycarbonate, etc. are preferably used.

In the present invention, "transparent" means a case where the visible light transmittance by a spectrophotometer is 80% or more, and the surface coating material is not transparent in order to suppress the decrease of the amount of light reaching the photovoltaic element as much as possible. Light transmittance is 30
In the region of 0 to 2100 nm, for example, 400 to 1200 nm for crystalline solar cells and 300 to 8 for thin film solar cells.
A transmittance as high as possible in the range of 00 nm is preferable, and 400
In the visible light wavelength region of up to 700 nm, 80% or more is desirable, and 90% or more is more desirable. When installed on the roof of a building, etc., the refractive index at 25 ° C. is 1.1 to 2.0 in order to facilitate the incidence of light from the atmosphere.
It is preferable that the area is.

[0021]

Embodiments of the present invention will now be described with reference to the drawings. FIG. 1 shows an embodiment of the solar cell module of the present invention and is a cross-sectional explanatory view of the main part. The solar cell module 1 is a colorless transparent float glass (white plate glass) having a thickness of 3 mm. Using ceramics ink on the substrate surface 2 of 3
Screen printing method with a screen of 50 mesh,
It has a structure in which a transparent substrate 4 having a plurality of convex bulges 3 is formed. In the convex bulging portions 3 provided on the base material surface 2 of the transparent substrate 4, the pitch between the convex portions 9 is approximately 50 to 50.
5000 μm, the height of the convex portion 9 is formed to be approximately 30 to 80 μm, and the convex bulge portion 3 is substantially evenly and regularly arranged on the substrate surface 2 of the translucent substrate 4, and a desired stripe, check, Alternatively, it is a structure formed in any one selected from a dot shape, a pattern, and a pattern shape.

FIG. 2 is a cross-sectional explanatory view of a main part showing a structure in which the surface coloring layer 10 is layered on the entire peripheral surface 12 of the convex bulging portion 3. The convex bulging portion 3 shown in FIG. 2 is formed by a pad printing or screen printing such as a gravure method in which the surface coloring layer 10 is an intaglio plate using colored ceramics ink on the entire peripheral surface 12 of the convex bulging portion 3. It is a layered structure. In addition, in the above-mentioned structure, the convex bulging portion 3 has the translucent substrate 4
The plate bleeding (bleeding) is apt to occur at the portion contacting the base material surface 2, but the bleeding phenomenon is caused by making the printing area of the plate slightly smaller than the entire peripheral surface of the convex bulge portion 3. Can be prevented.

In such a structure, the transmittance can be made as high as possible in order to avoid a decrease in the light transmittance, but the transmittance is somewhat increased by layering the surface coloring layer 10 of the convex bulge portion 3. Suppresses reflections,
Also, by adopting coloring and patterns on the wall and roof, it works to beautify the exterior of the building, design it with colors, and exert a decorative effect.

Further, in the present invention, the convex bulging portion 3 may be formed on the back surface side of the transparent substrate 4 by using the ceramic ink.

In the above-mentioned structure of the present invention, the light transmittance is inevitably lowered in view of the light transmittance, but since it has the effect of suppressing the light reflection and achieving the coloring effect, A desired color can be expressed as a whole in harmony with a wall surface and a roof, and a surface coloring layer 10 can be layered on the convex bulging portion 3 to give a desired color or pattern. .

Further, in the structure according to the present invention, as shown in FIG. 1, a conductive substrate 6 provided with a plating layer 5 serving as a photovoltaic element is provided on the back surface side of the transparent substrate 4. , A backside covering material 8 made of an insulating protective layer 7 on the backside thereof
Are formed, and these are integrally laminated.

The solar cell module according to the present invention is inevitably a decrease in the numerical value of the power generation performance of the module as an alternative type, as compared with the conventional popular type of expensive silicon solar cell module. Absent. However, at least according to the configuration of the present invention, the cost and maintenance cost of the module itself are low. Further, in the configuration of the present invention, in the case of a configuration for applying a desired color to the glass, generally, a decrease in light transmittance can be suppressed, the color can be manifested depending on the viewing direction, or the color can be observed in the same color tone by diffuse reflection. It works so that you can expect effects such as easy. Therefore, the desired light transmittance is set, the light transmittance value is substantially maintained, rainwater, dust, etc. can be easily removed even during long-term outdoor exposure, and a decrease in the value can be prevented. As well as a sense of color harmony on the exterior,
A solar cell module that satisfies sufficient practical use can be obtained.
As a result, the cost of the solar cell module itself can be reduced, and the convex bulging portion 3 formed on the front surface or the back surface of the translucent substrate 4 and the surface coloring layer 10 layered on the entire peripheral surface 12 thereof. The combination works to prevent diffuse reflection and surface reflection on the light incident surface side even if the small allowable light transmittance is reduced.

The present invention is not limited to the above-mentioned embodiment, and for example, the entire convex bulge is fixedly formed by the colored ceramic ink, and the design is within the scope of the present invention. Modifications and the like are included in the present invention.

[0029]

According to the present invention, the desired coloration is provided on the translucent substrate in a substantially uniform and regular manner, and the surface coloring layer is layered on the entire peripheral surface of at least the protrusion of the bulge. In addition to the coloring effect, the surface direct reflected light is suppressed by this, and rainwater, dust, etc. are easily removed by the formation of the bulging portion, and the power generation efficiency does not decrease even after long-term outdoor exposure. Further, the cost of the module itself is low, stable manufacturing is possible, the maintenance cost can be reduced, and it has an effect of satisfying sufficient practicality together with a color harmony in appearance as a building member.

[Brief description of drawings]

FIG. 1 is a cross-sectional explanatory view of essential parts showing an embodiment of a solar cell module according to the present invention.

FIG. 2 is an explanatory cross-sectional view of a main part showing a configuration in which a surface coloring layer is layered on the entire circumferential surface of a convex bulge portion.

[Explanation of symbols]

1 solar cell module 2 surface 3 convex bulge 4 Translucent substrate 5 plating layer 6 Conductive substrate 7 Insulation protection layer 8 Back coating material 9 convex 10 Surface coloring layer 11 Base material surface 12 circumference

Claims (3)

(57) [Claims] 1. A screen using ceramics ink on the surface of a substrate made of at least a light-transmissive glass material.
And a transparent substrate on which convex bulges are formed by a printing method, and the convex pitch and height of the convex bulges are formed substantially uniformly and regularly at a desired setting. On the back surface of the conductive substrate provided with a plating layer to be a photovoltaic element,
Further, in a solar cell module formed on the back surface with an insulating protective layer made of a back surface coating material, a surface coloring layer is layered on the entire peripheral surface of the convex bulging portion using colored ceramics ink. A solar cell module characterized in that 2. The solar cell module according to claim 1, wherein a convex bulge portion is formed on the back surface side of the transparent substrate using a ceramic ink. 3. The solar cell module according to claim 1, wherein the convex bulge has a stripe shape, a check shape, a dot shape or a pattern, a pattern shape, and an induction groove is formed.