JP3286577B2 - 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, and more particularly, to replacing conventional expensive silicon battery cells with low equipment cost, high photoelectric conversion efficiency, and long term module use. The present invention relates to a solar cell module capable of stably maintaining the power generation performance of a solar cell.

[0002]

2. Description of the Related Art In recent years, solar cell modules have been attracting attention as a clean energy source that does not generate pollution such as exhaust gas and radiation from the standpoint of global environmental protection. There are various forms of this solar cell, and typical ones are a crystalline silicon solar cell, a polycrystalline silicon solar cell,
There are amorphous silicon solar cells, compound semiconductor solar cells, and the like. Among these, thin-film crystalline silicon solar cells,
Amorphous silicon solar cells and the like can be manufactured at relatively low cost, and various developments have been made. 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. ing.

[0003]

However, in the above-mentioned single-crystal silicon solar cell, the use of a single-crystal silicon substrate has a disadvantage that the cost is increased. For this reason,
It has been proposed to use a low-cost heterogeneous substrate in place of a single-crystal silicon substrate and form a thin film of, for example, Si thereon. However, when the above-mentioned Si is formed to a required thickness, the substrate has a large difference in thermal expansion coefficient, so that the substrate is warped and the yield is inferior, and the electric characteristics are further deteriorated. As described above, various proposals for replacing the substrate have been made.
In addition to the complexity of the 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 any case, and the improvement is strongly desired in addition to the reduction of the equipment cost and the manufacturing cost. I have. Also, the solar cell module is
Because it is installed outdoors such as the rooftop of a building, it has not only light transmittance, but also weather resistance, water resistance, moisture resistance, mechanical strength,
Strict properties such as fire resistance and flame retardancy must be satisfied.

Further, for example, in a solar cell module using a resin film or the like as the outermost surface coating material, there is a problem that dirt easily adheres or accumulates during use. The incident light reaching the power element is reduced, and the photovoltaic power is reduced. The dirt deposited and deposited on the surface due to the natural environment such as rain, snow, wind and the like is usually removed to some extent. There is a drawback that they are easily attached and deposited and are hard to fall, and there is a problem that the electromotive force is greatly reduced.

When a resin film is used as the outermost surface coating material, the surface is smooth, so that light incident on the smooth surface at an angle close to parallel is totally reflected when the angle exceeds the critical angle, and the solar cell is used. Since light does not enter the photovoltaic element, sufficient electromotive force cannot be generated. Also, when installing on the rooftop or wall of a roof,
Depending on the angle of the solar cell module, the reflected light reaches other houses or the like, so that there may be a problem that people feel dazzling and uncomfortable. In addition, wrinkles may occur on the surface due to repeated thermal expansion and thermal shrinkage of the coating material due to long-term outdoor exposure, which impairs the aesthetic appearance. In order to solve such a drawback, the surface of the solar cell module is provided with irregularities, and usually, a metal mesh such as an aluminum mesh or a stainless steel mesh or a woven fabric is used.

As described above, forming irregularities on the surface of a substrate in a solar cell and thereby reducing surface reflection improves light absorption in the solar cell element, reduces the surface direct reflected light, and provides a sufficient start-up. In order to obtain electric power, it is important as one of the elemental technologies for increasing the efficiency of photoelectric conversion. Fine irregularities are provided on the surface to increase the energy conversion rate or to prevent the conversion rate from decreasing. A solar cell module has been proposed. For example, Japanese Patent Application Laid-Open No. HEI 9-191115 discloses that a light incident side surface of a photovoltaic element is in contact with a transparent organic polymer resin layer, and two or more transparent surface protection film layers are formed on the outermost surface of the layer. In a solar cell module covered with a material, a plurality of irregularities are formed on the surface of the covering material, and the pitch, height, groove length, and wire diameter of the irregularities are disclosed. Also, Japanese Patent Application Laid-Open No. Hei 9-14860
Japanese Patent Application Laid-Open No. 3 (1999) -1995 discloses a substrate in which a substantially V-shaped or U-shaped concave and convex groove is formed on a light-receiving surface by a wheel-shaped multi-blade grindstone that swings a blade having a substantially V-shaped or U-shaped cross section on a ground surface. A solar cell comprising: Further, JP-A-9-10
No. 2625 proposes a method for manufacturing a solar cell element in which a semiconductor substrate is carried into a dry etching apparatus, and a gas for forming a mask and an etching gas are simultaneously introduced into the apparatus to form minute uneven portions. .

However, in Japanese Patent Application Laid-Open No. Hei 9-191115, the light incident surface of the photovoltaic element has two or more transparent organic polymer resin layers and a transparent surface protective film on the outermost surface in contact with the transparent organic polymer resin layer. It is a configuration covered with a coating material of
The surface direct reflection light is small, wrinkles are not easily formed, and dirt is easy to remove.However, a transparent organic polymer resin layer impregnated with a fibrous inorganic compound is Since the coating material has at least two or more surface protective film layers transparent on the surface, the structure is complicated and the material and the production cost are increased. In Japanese Patent Application Laid-Open No. Hei 9-148603, groove processing for reducing the light reflectance of a substrate is performed using a wide multi-blade grindstone having a large number of blades.
A machine tool for grinding a substrate is required, and there is a disadvantage that high cost cannot be avoided unless processing for forming regular grooves and mass productivity are secured. Further, Japanese Patent Laid-Open No. 9-1
In Japanese Patent No. 02625, even if the manufacturing process is simplified and the entire surface of the semiconductor can be uniformly etched, the cost of the manufacturing apparatus is high and the flow rate of the gas used needs to be controlled.

[0008]

SUMMARY OF THE INVENTION The present invention has been made as a result of intensive studies to solve the above problems. (1) The light-transmitting substrate has fine uneven ridges formed on the surface of the transparent float glass by a screen printing method using a ceramic ink. And a configuration in which the heights of the irregularities are approximately equal to a desired setting and formed regularly. The uneven bulge is formed by any one of stripe, check, and dot shapes by a screen printing method, and the uneven bulge has a plurality of uneven bulges. The pitch between them is 50 μm to 5000 μm, and the height of the unevenness is formed in a desired range of 10 μm to 100 μm. (2) On the surface in contact with the translucent substrate, a conductive electrode layer substrate provided with a plating layer serving as a photovoltaic element is formed for efficiently collecting current. (3) Further, on the back surface, sufficient electrical insulation can be ensured in order to maintain electrical insulation between the conductive substrate of the photovoltaic element and the outside, and furthermore, it has excellent long-term durability and thermal expansion or contraction. This is a configuration in which a back surface covering material made of a durable insulating protective layer is provided.

Further, since the solar cell module is installed on the roof of a house or the like, it is required to be flame-retardant. Therefore, in the present invention, ceramic ink and, if necessary, tourmaline ore are mixed in the uneven bulging portion. Use the used ink.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The solar cell module of the present invention comprises:
Based on the above-described configuration, the present invention includes the following configuration modes, and thereby has a remarkable effect.

The light-transmitting substrate used in the present invention is a transparent glass plate or a plate made of transparent float glass (white plate glass) that transmits light, and is colorless and transparent, or a colored transparent glass plate if necessary. A synthetic resin plate or the like can be used.
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 appropriate. On the light incident surface side surface of the translucent substrate,
Fine irregularities are formed by a screen printing method using ceramic ink. The irregularities pitch and irregularities between the irregularities are formed in a desired uniform and regular manner. Configuration. The uneven bulge is formed by a screen printing method in any one of stripe, check and dot shapes. The translucent substrate has a plurality of uneven ridges, and at least a pitch between the uneven ridges is 50 μm to 50 μm.
00 μm and the height of the unevenness is 10 μm to 100 μm.
m, and a screen mesh and stripe satisfying the conditions of the above range.
By selecting and combining any one of the check and dot shapes, for example, using a screen of usually 300 mesh or less, suitably 80 to 200 mesh, a concavo-convex bulging portion matching a desired setting range is formed. be able to.

Further, the light-transmitting substrate satisfies the condition of being optically transparent, and is not only light-transmitting, but also has adhesion, deposition and weather resistance on the light incident surface side during long-term outdoor exposure. It is necessary to satisfy conditions such as moisture resistance, fire resistance against fire, and flame retardancy. In particular, in the case of a light-transmitting substrate on which a plurality of uneven ridges are formed according to the present invention, the effect of reducing surface reflection can be expected due to the presence of the minute uneven ridges. In addition, it is desired to prevent appearance defects in addition to prevention of deposition and easy removal of dirt. Therefore, in the present invention, it is possible to use a surface covering material having multi-functionality that prevents the light receiving surface from being stained or that is easily removed even if stains adhere to the light receiving surface due to long-term outdoor exposure conditions. For example, for example, a ceramic ink obtained by kneading a powder of tourmaline ore, which exerts an action of forming an electric field of minus static electricity, may be used to achieve a function of preventing such contamination. More 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, snow and hail. An easy configuration can be obtained. Therefore, in the present invention, the necessary light transmittance is ensured by the configuration of the light-transmitting substrate as described above, the light directly reflected on the surface is reduced, the light-collecting efficiency is improved, and the reflectance of the light-receiving surface is improved. To prevent a decrease in the photoelectric conversion efficiency of the solar cell module even during long-term use.

In the present invention, it is natural that the light-transmitting substrate satisfies the condition of being optically transparent. It is also possible to adopt a structure in which a bulge is similarly formed on the rear surface side of the light-transmitting substrate other than the light incident surface side using ceramic ink.

Next, a conductive electrode layer substrate provided with a plating layer serving as a photovoltaic element for efficiently collecting current is formed on a surface in contact with the light-transmitting substrate. In addition, the quality control is extremely simple and the module
Power generation performance of the vehicle can be stably maintained. The plating layer is formed as a plating layer serving as a photovoltaic element on the back surface in contact with the translucent substrate. This electrode is formed by a vacuum deposition method, a sputtering method, a spray method,
It can be formed by a normal pressure CVD method or another appropriate method. As a material for 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, on the back surface of the conductive electrode layer substrate, a back surface covering material made of an insulating protective layer is formed. The covering material is necessary for maintaining electrical insulation. Desirably, sufficient electrical insulation can be ensured, durability is excellent for a long time, heat resistance and heat contraction are provided, and flexibility is provided. Polyamide, polyethylene terephthalate, polycarbonate and the like are preferably used. .

In the present invention, the term "transparent" means that the visible light transmittance of the spectrophotometer is at least 80% or more. In order to suppress the decrease in the amount of light reaching the photovoltaic element as much as possible, the surface coating material is transparent. For example, in a visible light wavelength region having a light transmittance of 400 nm or more and 800 nm or less, the light transmittance is preferably 80% or more, and more preferably 90% or more. Moreover, when installed on the roof of a building or the like, it is preferable that the refractive index at 25 ° C. is in the range of 1.1 to 2.0 in order to facilitate the incidence of light from the atmosphere.

[0017]

Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows an embodiment of the solar cell module of the present invention, and is an explanatory view showing a cross section. In FIG. 1, reference numeral 1 denotes a solar cell module.
The surface 1 of the colorless and transparent float glass (white glass) having a thickness of 3 mm is formed on a light incident side surface 2 by using a ceramic ink and a 350 mesh screen by a screen printing method. It has a configuration in which the light-transmitting substrate 4 having the raised and recessed portions is formed. The raised and recessed portions 3 provided on the surface of the translucent substrate 4 have a pitch of approximately 50 to
It is formed to have a size of 5000 μm and a height of irregularities of about 50 to 100 μm. Further, the raised and recessed portions 3 are formed on the surface of the light-transmitting substrate 4 in a substantially uniform and regular manner. Further, a conductive electrode layer substrate 6 provided with a plating layer 5 serving as a photovoltaic element is provided on the back surface side of the translucent substrate 4, and a back surface made of an insulating protective layer 7 is provided on the back surface side. A coating material 8 is formed and these are integrally layered.

FIG. 2 shows another embodiment of the present invention, in which a colorless and transparent float glass is used. In the case of FIG. 1, a bulge 3 is formed on the surface 2 on the light incident side. On the other hand, the raised and recessed portions 3 are also provided on the rear surface side of the light-transmitting substrate 4 by screen printing using ceramic ink. For this reason, the translucent substrate 4 on which the raised and recessed portions 3 are formed is in a connected state with the plating layer 5 on the back surface side. It is configured so that it is absorbed as a bite state and there is no particular hindrance.

The solar cell module shown in FIGS. 1 and 2 is an alternative type of the conventional solar cell module having a lower power generation performance as compared with the conventional popular expensive silicon solar cell module. Is inevitable. However, at least according to the configuration of the present invention, the cost of the module itself and the maintenance cost are low, and when a desired light transmittance is set, the value of the light transmittance is substantially maintained, and the module is maintained for a long time. Thus, a solar cell module satisfying sufficient practicality as a building member can be obtained. As a result, the cost of the solar cell module itself can be reduced, and the amount of condensed light increases due to the bulges 3 formed on the front surface or the back surface of the light-transmitting substrate 4, and irregular reflection on the light incident surface side occurs. And work to prevent surface reflection.

It should be noted that the present invention is not limited to the above-described embodiment, and design changes and the like within the scope of the present invention are included in the present invention.

[0021]

According to the present invention, a substantially uniform and regular bulging and recessed portion of a desired setting provided on one of the front and back surfaces of the translucent substrate is formed.
The reflectance of the light-receiving surface of the substrate is reduced to prevent a decrease in photoelectric conversion efficiency, the light absorption is increased, the characteristics of the solar cell are improved, and the power generation efficiency is not reduced even after long-term outdoor exposure. In addition, if necessary, a configuration can be adopted in which dirt hardly adheres due to mixing of multifunctional materials. Further, the present invention provides a highly practical solar cell module that can be manufactured stably at a low cost, can be stably manufactured, can reduce the maintenance and management costs, and can be used.

[Brief description of the drawings]

FIG. 1 is an explanatory sectional view of a main part showing an embodiment of a solar cell module of the present invention.

FIG. 2 is an explanatory sectional view of a main part showing another embodiment of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 solar cell module 2 front surface 3 bulges 4 translucent substrate 5 plating layer 6 conductive electrode layer base 7 insulating protective layer 8 back surface coating material

Claims (4)

(57) [Claims] 1. A light-transmitting substrate made of transparent float glass, a conductive electrode layer substrate provided with a plating layer serving as a photovoltaic element on the back surface in contact with the substrate, and a back surface on the back surface Solar cell module comprising an insulating protective layer comprising a coating material
A ceramic on the surface of the transparent float glass.
1. A light-transmitting substrate having a plurality of uneven ridges formed by a screen printing method using ink and ink , wherein the substrate has a plurality of uneven ridges and at least a pitch of unevenness of 50 .mu.m.
A solar cell module characterized in that the bulges having a height of up to 5000 μm and a height of irregularities of 10 μm to 100 μm are formed substantially uniformly and regularly in a desired setting. 2. The solar cell module according to claim 1, wherein the uneven bulges are formed in a stripe, a check or a dot shape by a screen printing method. 3. A ceramic material is provided on the back of the transparent float glass.
3. The solar cell module according to claim 1, wherein the projections and depressions are formed by a screen printing method using a black ink . 4. The solar cell module according to claim 1, wherein said ceramic ink contains at least 5 to 15% by weight of tourmaline ore having an average particle size of 0.1 μm to 0.5 mm.