JPH09321329A - Solar cell element, solar cell device and lighting system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress the reduction of the quantity of light received on a photo detecting surface of a solar cell substrate due to contamination, facilitate the maintenance, provide a high sensitivity of the substrate superior in generating efficiency and protect the substrate in the ultraviolet wavelength range. SOLUTION: A photocatalystic film 6 permeable to lights in a longer wavelength range than that of ultraviolet rays but blocking those in the ultraviolet wavelength range is formed on a photo detecting surface of a solar cell substrate 2 to oxidize and decompose organic substances by this film 6. This film 6 is permeable to lights in a longer wavelength range than that of ultraviolet rays and hence provides a high sensitivity of the substrate 2 and superior generating efficiency. The film 6 blocks lights in the ultraviolet wavelength range to thereby protect the solar cell substrate 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solar cell element that converts light energy into electric energy, a solar cell device using the solar cell element, and a lighting system.

[0002]

2. Description of the Related Art Conventionally, a solar cell element has been used in combination for power generation, as an auxiliary power source for various electric devices, and as a main power source by utilizing the characteristic of converting light energy into electric energy. There is.

Especially when used outdoors, electromotive force can be efficiently obtained by receiving the light energy of sunlight. When used outdoors, for example, there are road display boards and traffic lights, lighting equipment, etc., which store the electromotive force of solar cell elements in a storage battery during the daytime and during the nighttime. The lamp etc. are turned on by the electric power stored in the storage battery. When the solar cell element is used, it is used in a state where the light receiving surface of the solar cell element is directly exposed to the outside or in a state where the light receiving surface of the solar cell element is covered with a translucent cover.

On the other hand, in Japanese Patent Laid-Open No. 8-71370,
It is described that a harmful gas such as CO ₂ (carbon dioxide) or NO _x (nitrogen oxide) contained in the exhaust gas of an automobile is removed by a photocatalyst film. The photocatalyst film removes harmful gas by receiving sunlight, and at the same time receives the sunlight that is not absorbed by the photocatalyst film and is transmitted to the solar cell element to charge the storage battery. After sunset,
The auxiliary lamp is turned on so that the photocatalytic film is irradiated with light including ultraviolet rays by the power supplied from the storage battery, and the photocatalytic film irradiated with the light from the auxiliary lamp removes harmful gas.
It is possible to remove harmful gases day and night.

[0005]

As described above, when the solar cell element is used outdoors, the light-receiving surface of the solar cell element or the surface of the translucent cover covering the light-receiving surface is, for example, in the exhaust gas of an automobile. Due to the inclusion of dirt components such as oil mist and carbon contained in, dust and dirt are likely to adhere and stain easily. Due to this dirt, the light transmittance of the light receiving surface of the solar cell element decreases, and the electromotive force decreases. Therefore, it is necessary to frequently clean the light-receiving surface of the solar cell element and the light-transmitting cover, and maintenance is troublesome.

[0006] Further, the solar cell element has high sensitivity to light rays in a longer wavelength region than ultraviolet rays included in sunlight and has excellent power generation efficiency, but is easily deteriorated by ultraviolet rays and shortens its life. It has been confirmed by experiments that it becomes a factor.

Further, in the structure described in Japanese Patent Laid-Open No. 8-71370, the photocatalytic film is formed on the light receiving surface of the solar cell element, but it is not the removal of the dirt component but C
Since it is intended to remove harmful gases such as O ₂ and NOx, it requires a large decomposing power and must be formed with a certain thickness. If the light transmittance is sacrificed by increasing the film thickness in this way, the improvement of the electromotive force of the solar cell cannot be expected. Further, no consideration is given to the maintenance of efficiency of the solar cell element and consideration of deterioration due to ultraviolet rays.

The present invention has been made in view of the above circumstances, and suppresses a decrease in the amount of received light due to dirt and facilitates maintenance. Further, the sensitivity of the solar cell substrate is high and the power generation efficiency is excellent. An object of the present invention is to provide a solar cell element, a solar cell device and a lighting system capable of protecting a solar cell substrate against a wavelength range.

[0009]

A solar cell element according to claim 1 is a solar cell substrate having a light receiving surface; formed on the light receiving surface of the solar cell substrate and transmitting light rays in a wavelength range longer than ultraviolet rays. And a photocatalyst film that blocks the ultraviolet wavelength range.

The solar cell element is a polycrystal type, a single crystal type, an amorphous type silicon solar cell, a GaAs solar cell, or a C solar cell.
Known materials such as dS / Cu ₂ S solar cells can be applied. Both of them have high sensitivity to light rays in a wavelength range longer than that of ultraviolet rays and have excellent power generation efficiency.

The photocatalyst film oxidizes and decomposes the organic substance in the photocatalyst film by ultraviolet rays of about 410 nm or less contained in external light such as sunlight, and the organic substance adheres to the surface of the light receiving surface of the solar cell substrate. Prevent. This photocatalytic action suppresses a decrease in the amount of light received by the solar cell element and facilitates maintenance. Further, in the case of outdoors, the dirt component decomposed due to the attachment of water drops such as rainwater to the light receiving surface is washed away, and the dirt removing action is promoted.

The photocatalyst film transmits a large amount of light in the wavelength range of about 410 nm or more, which has high sensitivity of the solar cell substrate and is excellent in power generation efficiency, and the photocatalyst film has a thickness of about 410 nm or less for protecting the solar cell substrate. Blocks ultraviolet rays in the wavelength range.

Therefore, the photocatalyst film transmits a large amount of light in the wavelength range of about 410 nm or more and also has a thickness of about 410 nm.
The material is not limited as long as it is formed so as to block ultraviolet rays in the following wavelength range, but is preferably Ti
At least one selected from O ₂ , ZnO, and FeTiO ₃ is formed as a main component. The photocatalyst film can be formed by a sol-gel method, a CVD method, a vapor deposition method, etc.
It can be formed by a method other than these.

The solar cell element according to claim 2 is the solar cell element according to claim 1.
In the described solar cell element, the photocatalytic film has a thickness of 0.0
It is 1 to 0.5 μm, and if it is less than 0.01 μm, effective photocatalytic activity cannot be expected, and if it exceeds 0.5 μm, the transmittance becomes small and electromotive force cannot be obtained.

The solar cell element according to claim 3 is the solar cell element according to claim 1.
Alternatively, in the solar cell element according to the item 2, if the total transmittance of the photocatalyst film is 90% or more and less than 90%, a large electromotive force cannot be obtained.

The solar cell element according to claim 4 is the solar cell element according to claim 1.
In the solar cell element according to any one of items 1 to 3, the photocatalyst film is formed mainly of anatase crystalline titania (TiO ₂ ). This further improves the photocatalytic action.

The solar cell element according to claim 5 is the solar cell element according to claim 1.
In the solar cell element according to any one of items 1 to 4, the photocatalyst film is formed via an intermediate layer containing silica (SiO ₂ ) as a main component. This prevents the photocatalytic film from being affected and deteriorated by the substance extracted from the solar cell substrate.

According to a sixth aspect of the present invention, there is provided a solar cell device including a solar cell element having a light-receiving surface; a translucent cover covering the light-receiving surface of the solar cell element; And a photocatalytic film that transmits light in the long wavelength range and blocks the ultraviolet wavelength range.

Similarly to the above, the photocatalytic action suppresses a decrease in the amount of light received due to dirt on the translucent cover, and facilitates maintenance. Further, the translucent cover may be formed of various materials as long as it is a translucent member such as a translucent resin integrally molded with the solar cell element or a separately covered resin, glass, ceramics, or the like. .

A solar cell device according to claim 7; a solar cell element having a light-receiving surface; a main body accommodating the solar cell element and having an opening formed so as to face the light-receiving surface of the solar cell element; A light-transmitting cover attached to the opening of the main body so as to cover the light-receiving surface of the photocatalyst; a photocatalyst formed on at least the surface of the light-transmitting cover, which transmits light rays in a wavelength range longer than ultraviolet rays and blocks ultraviolet ray wavelength ranges. With a membrane;
It is provided with a control circuit for controlling electromotive force from the solar cell element housed in the main body; and a storage battery housed in the main body.

In the same manner as described above, the photocatalytic action suppresses a decrease in the amount of received light due to contamination of the light receiving surface of the solar cell element,
Maintenance becomes easy. If the electromotive force of the solar cell element is stored in the storage battery, the power stored in the storage battery can be used.

The solar cell device according to claim 8 is the solar cell device according to claim 6.
Alternatively, in the solar cell device according to 7, the thickness of the photocatalyst film is 0.01 to 0.5 μm, and if it is less than 0.01 μm, effective photocatalytic activity cannot be expected, and if it exceeds 0.5 μm, the transmittance becomes small. , No electromotive force can be obtained.

A solar cell device according to claim 9 is the solar cell device according to claim 6.
In the solar cell device according to any one of items 1 to 8, if the total transmittance of the photocatalytic film is 90% or more and is less than 90%, a large electromotive force cannot be obtained.

A solar cell device according to a tenth aspect is the solar cell device according to any one of the sixth to ninth aspects, wherein the photocatalytic film is formed mainly of anatase crystalline titania (TiO ₂ ). is there. This further improves the photocatalytic action.

A solar cell device according to claim 11 is the solar cell device according to any one of claims 6 to 10.
The photocatalyst film is formed via an intermediate layer containing silica (SiO ₂ ) as a main component. This prevents the photocatalytic film from being affected and deteriorated by the substance extracted from the translucent cover.

An illumination system according to a twelfth aspect comprises the solar cell element according to any one of the first to fifth aspects; and an illuminating device utilizing an electromotive force of the solar cell element. As a result, maintenance can be facilitated and stable electromotive force can be used with little reduction in electromotive force.

An illumination system according to a thirteenth aspect comprises the solar cell device according to any one of the sixth to eleventh aspects; and an illumination device that utilizes electromotive force from the solar cell device. As a result, maintenance can be facilitated and stable electromotive force can be used with little reduction in electromotive force.

[0028]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 and FIG. 2 show a first embodiment. FIG. 1 is a partial cross-sectional view of a solar cell element, FIG. 2 (a) is a spectral total transmittance characteristic diagram of a photocatalytic film, and FIG. 2 (b) is a spectral sensitivity characteristic diagram of a solar cell substrate.

The solar cell element 1 has a solar cell substrate 2, and this solar cell substrate 2 has alumina (Al ₂ O ₃ )
Polycrystalline silicon 4 is formed on a manufactured substrate 3. Polycrystalline silicon 4 is formed in a semiconductor structure having a pn junction of p layer 4a and n ⁺ layer 4b. An electrode (not shown) is arranged between the substrate 3 and the polycrystalline silicon 4. The surface layer (upper surface) of the solar cell substrate 2 serves as a light-receiving surface 5 that receives light rays, converts light energy such as sunlight rays into electric energy, and generates electromotive force.

A photocatalytic film 6 is formed on the light receiving surface 5 of the solar cell substrate 2.
Are formed. The photocatalyst film 6 has an intermediate layer containing silica (SiO ₂ ) as a main component on the surface of the light receiving surface 5, and then has anatase crystalline form of titania (TiO ₂ ) as a main component on the surface of the intermediate layer. Has been formed.

The intermediate layer is formed of silica fine particles having a particle size of 60 nm to 200 nm with a thickness of 0.5 μm to 2 μm. The starting materials are Me ₃ SiNHSiMe ₃ (hexamethyldisilazane) and [Me ₂ SiNH ] ₃ (hexamethylcyclotrisilazane), for example, is formed by immersing it in a solution manufactured by Tonen Co., Ltd., pulling it up, drying it, and baking it at a temperature of 80 ° C. The intermediate layer transmits 80% or more of visible light and at least a part of ultraviolet rays in the wavelength range of 300 nm to 400 nm. Solar cell substrate 2
It is possible to prevent the photocatalytic film 6 from being affected and deteriorated by the substance extracted from the side.

The photocatalyst film 6 is formed by dissolving an organic titanium compound as a main component in a solvent such as alcohol to prepare a titanium alcoholate solution, applying it by a sol-gel method, and baking it at a high temperature. The photocatalyst film 6 has a thickness of 0.01 μm so as to transmit at least 90% or more of a wavelength range longer than ultraviolet rays.
It is formed to a film thickness within the range of m to 0.5 μm.

That is, the photocatalyst film 6 is mainly configured to transmit more light rays in the longer wavelength region than ultraviolet rays and block the ultraviolet wavelength region. That is,
The result of measuring the relative spectral transmittance of the photocatalyst film 6 is shown in FIG.
As shown in (1), it mainly blocks the wavelength range of ultraviolet rays of about 410 nm or less and transmits a large amount of light rays of the wavelength range of about 410 nm or more.

Approximately 550 nm exceeding 410 nm
However, the total transmittance in the visible and infrared wavelength regions over about 550 nm is 94%.

The ultraviolet transmittance in the wavelength region shorter than about 350 nm is 50% or less.

Next, the operation of the first embodiment will be described.

The solar cell element 1 converts the light energy received by the light receiving surface 5 into electric energy, and an electromotive force is obtained. In particular, when used outdoors, electromotive force can be efficiently obtained by receiving strong light energy of sunlight.

When the solar cell element 1 is incorporated and used in equipment used outdoors, it is affected by dust, exhaust gas of automobiles, etc., and dust, carbon, oil or the like is formed on the outer surface of the light receiving surface 5. Substances such as mist, acetaldehyde, methyl mercaptan, hydrogen sulfide or ammonia adhere. However, the photocatalytic film 6 is formed on the surface of the light receiving surface 5.
Since the photocatalyst film 6 is formed, it is possible to reduce the contamination of the light receiving surface 5 due to the photocatalytic action of the photocatalytic film 6.

That is, about 410n contained in the sun rays.
When the photocatalytic film 6 is irradiated with ultraviolet rays having a wavelength range of m or less,
A hole is generated inside the titania fine particles, and this hole has a force of extracting electrons by the energy of a band gap of about 3.0 eV, that is, an oxidizing power, and the oxidizing power of this hole causes the photocatalytic film 6 to be attached or contacted. Change the substance.

As a result, the photocatalyst film 6 is less likely to be contaminated with dirt, and the effect of facilitating the removal of dirt once adhered to the photocatalyst film 6 can be suppressed, and a decrease in the amount of light received due to dirt on the light-receiving surface 5 can be suppressed.

Therefore, even if the above substances are deposited on the light receiving surface 5 of the solar cell element 1, the adhesion of these substances is effectively prevented and the solar cell element 1 reaches the solar cell element 1 through the light receiving surface 5. It is possible to prevent a decrease in luminous flux, improve power generation efficiency, do not need to frequently clean the light-receiving surface 5 or the like, and facilitate maintenance.

Further, since the photocatalytic film 6 blocks the wavelength range of ultraviolet rays of about 410 nm or less, the solar cell substrate 2 can be protected against the wavelength range of the ultraviolet rays, and the solar cell substrate 2 can have a long life.

By the way, the solar cell substrate 2 has a silicon-based solar cell (a) of a polycrystalline type, a single crystalline type, an amorphous type or the like.
-Si, c-Si), AIGaAs / GaAs -based solar cell, CdS / Cu ₂ S, are well-known solar cell materials such as CdS / CTe solar cell is applicable. And FIG.
As shown in (b), the results of measuring the spectral sensitivities of various solar cell materials show that all of the solar cell materials are highly sensitive to light rays in the longer wavelength range than ultraviolet rays and are excellent in power generation efficiency.

Therefore, the photocatalyst film 6 has a thickness of about 410 nm.
Although it is configured to block ultraviolet rays in the following wavelength range, it transmits a large amount of light in a longer wavelength range than the ultraviolet rays, and therefore maintains high sensitivity without impairing the sensitivity of the solar cell substrate 2, which is excellent. The power generation efficiency can be obtained.

Further, since the photocatalyst film 6 is formed mainly of anatase crystal type titania (TiO ₂ ), the photocatalytic action can be further improved.

Further, since the photocatalyst film 6 is formed through the intermediate layer containing silica (SiO ₂ ) as a main component, the photocatalyst film 6 is affected by the substance extracted from the solar cell substrate 2 and deteriorates. Can be prevented.

Next, FIG. 3 shows a second embodiment. FIG. 3 is a cross-sectional view of the solar cell device.

In this embodiment, a plurality of solar cell elements 1 electrically connected by the element connecting wires 11 are molded with a transparent moisture resistant resin 12, and this is molded into a container 13 as a translucent cover.
Solar cell module as a solar cell device
Form 14. Container 13 facing the light receiving surface 5 of the solar cell element 1
The photocatalyst film 6 similar to that of the first embodiment is formed on the surface of the.

Then, by the photocatalytic action of the photocatalytic film 6,
It is possible to prevent the surface of the container 13 facing the light receiving surface 5 of the solar cell element 1 from being soiled and to facilitate maintenance.

Therefore, also in the second embodiment, the same operational effect as in the first embodiment can be obtained.

Next, FIGS. 4 and 5 show a third embodiment. FIG. 4 is an enlarged cross-sectional view of a part of the solar cell device, FIG.
FIG. 4 is a side view of the solar cell device.

In FIG. 5, the solar cell device 21 includes a main body 22.
The solar cell element 1 is housed on the upper surface of the main body 22 and an opening 23 is formed so that the light receiving surface 5 of the solar cell element 1 faces.
Are formed. The solar cell element 1 is provided in the opening 23 of the main body 22.
A transparent cover 24 is attached so as to cover the light receiving surface 5 of the.

As shown in FIG. 4, on the light-receiving surface 5 of the solar cell element 1, a transparent water-resistant resin layer 25 of, for example, acryl or PBT resin is formed. Further, the photocatalyst film 6 is formed on the surface (upper surface) of the translucent cover 24 as in the first embodiment.
Are formed. If the translucent cover 24 is made of resin and the photocatalyst film 6 needs to be formed at a low temperature,
Titania suspension is dispersed (TiO ₂₎ fine particle coating, drying may be film forming.

A control circuit 26 for controlling electromotive force from the solar cell element 1 and a storage battery 27 such as a Ni—Cd battery cell are housed in the main body 22. The control circuit 26 compares the electromotive force values of the solar cell elements 1 and controls the storage battery 27 to be charged during the day and output the power of the storage battery 27 during the night.

The photocatalytic action of the photocatalytic film 6 can prevent the surface of the translucent cover 24 from being contaminated, so that the luminous flux reaching the solar cell element 1 through the translucent cover 24 can be prevented from lowering. The power generation efficiency can be improved.

In the solar cell device 21, the solar cell element 1 having the photocatalytic film formed on the light receiving surface 5 may be used as in the first embodiment. In this case, for example, exhaust gas enters between the solar cell element 1 and the translucent cover 24, or the light-receiving surface 5 of the solar cell element 1 is contaminated by gas or water mold generated from plastic or rubber in the device. Can be prevented. Therefore, it is possible to prevent a decrease in the luminous flux reaching the solar cell element 1, improve the power generation efficiency, do not need to frequently clean the light receiving surface 5 or the like, and facilitate maintenance.

Therefore, also in the third embodiment, the same operational effect as that of the first embodiment can be obtained.

Next, FIG. 6 shows a fourth embodiment. FIG. 6 is an explanatory diagram of the lighting system.

In the figure, 31 is a pillar standing upright on the side of a road or the like, and a solar cell device 32 is arranged at the upper end of this pillar 31. This solar cell device 32 includes a plurality of solar cell elements 1
Are arranged in a plane, and a photocatalytic film is formed on the light-receiving surface 5 of the solar cell elements 1 as in the first embodiment.

An illumination device 33 is arranged near the upper end of the column 31. The illuminating device 33 has a fixture main body 34 attached to the support column 31, a lamp is built in the fixture main body 34, and the lamp is covered with a light-transmitting globe 35.

A sign board 36 as an illuminating device is arranged in the middle of the pillar 31. The signboard 36 has a cold cathode fluorescent lamp 38 and a light guide plate 39 housed inside a main body 37, and an acrylic panel 40 on which pictographs such as road names are printed is arranged outside the main body 37. There is. Then, when the cold cathode fluorescent lamp 38 is turned on, the light emitted from the cold cathode fluorescent lamp 38 is applied to the panel 40 through the light guide plate 39, and the panel
Illuminate 40 from the back.

A control box 41 is disposed below the column 21, and a control circuit 42 and N are provided in the control box 41.
A storage battery 43 such as an i-Cd battery cell is arranged. The storage battery 43 is connected to the solar cell element 1 so that it can be charged by the electromotive force of the solar cell element 1, and can supply the stored power to at least one of the lighting device 32 and the sign board 36.

Then, the control circuit 42 compares the electromotive force values of the solar cell elements 1 to charge the storage battery 43 at daytime and outputs the power of the storage battery 43 to at least one of the lighting device 32 and the sign board 36 at night. Control to do. The control circuit 42 also functions as a photo switch that detects the amount of outside light.

By forming a photocatalytic film on the surface of the transparent cover 35 and the surface of the marker plate 36 of the lighting device 32,
The surfaces of the translucent cover 35 and the sign plate 36 can be prevented from becoming dirty, and maintenance can be facilitated.

Therefore, also in the fourth embodiment, the same operational effects as those in the first embodiment can be obtained.

The solar cell element 1 can be used not only in a lighting system but also in combination with an electric device utilizing electric power, and in that case, the same effect can be obtained.

As another embodiment, the solar cell element or the solar cell device can be used as a power source for an electric shock killer which is installed outdoors.

The electric shock insect killer is a device for attracting insects by using a complement insect fluorescent lamp that mainly emits the light that the insects prefer, touching the insects with a high-voltage electric shock grid, and instantaneously electrocuting them. Is. The electrocuted insects fall into the saucer of the device. However, the insects killed by the electric shock on the electric shock grid adhere to the electric shock grid,
Or it falls on the saucer part of the device. The insects in the saucer dry and become stuck due to the heat of the sun's rays, the insect complement fluorescent lamp and the equipment itself. Cleaning up stuck insects is very troublesome.

Therefore, a photocatalytic film is applied to the saucer part of the electric shock insecticide. In addition, since it is possible that insects may stick to the peripheral part of the equipment, the lattice part, and the complement insect fluorescent lamp, a photocatalytic film is also applied to those parts. The spectral distribution of the complement insect fluorescent lamp has a peak wavelength of 365 nm and a wavelength effective for activating the photocatalytic film is 350 to 410 nm, and is therefore effective for decomposing insects.

In the electric shock killer, the insects attracted by the supplementary fluorescent lamp touch the high-voltage electric shock grid to be electrocuted. Insects killed by electric shock attach to the surface of the electric shock grid,
It falls on the saucer. A photocatalytic film is applied to the electric shock grid and the saucer, and the insects are decomposed by the insecticidal fluorescent lamp or the photocatalytic film that receives the opposing light rays in the daytime because they are organic substances. By coating the photocatalytic film on the electric shock killer, it is possible to prevent insects from sticking and to facilitate cleaning.

[0072]

According to the solar cell element of claim 1,
Since the photocatalyst film is formed on the light receiving surface of the solar cell substrate, it is possible to suppress the decrease in the amount of light received due to dirt on the light receiving surface, facilitate maintenance, and because the photocatalyst film transmits light rays in the wavelength range longer than ultraviolet rays. The solar cell substrate has high sensitivity and excellent power generation efficiency, and since the photocatalytic film blocks the ultraviolet wavelength region, the solar cell substrate can be protected against ultraviolet rays and the life can be extended.

According to the solar cell element of claim 2, in addition to the effect of the solar cell element of claim 1, the photocatalyst film has a film thickness of 0.01 to 0.5 μm, which is smaller than 0.01 μm. Therefore, the effective photocatalytic activity cannot be expected, and when it exceeds 0.5 μm, the transmittance becomes small and the electromotive force cannot be obtained. Therefore, the optimum range of the film thickness of the photocatalytic film can be set.

According to the solar cell element of claim 3, in addition to the effect of the solar cell element of claim 1 or 2, when the total transmittance of the photocatalyst film is 90% or more and less than 90%, Since a large electromotive force cannot be obtained, the optimum range of the total transmittance of the photocatalytic film can be set.

According to the solar cell element of claim 4, in addition to the effect of the solar cell element of any one of claims 1 to 3, the photocatalyst film is made of anatase crystalline titania (Ti).
The photocatalytic action can be further improved by forming O ₂ ) as the main component.

According to the solar cell element of claim 5, in addition to the effect of the solar cell element of any one of claims 1 to 4, the photocatalyst film has an intermediate layer containing silica (SiO ₂ ) as a main component. By forming via the above, it is possible to prevent the photocatalytic film from being affected and deteriorated by the substance extracted from the solar cell substrate.

According to the solar cell device of the sixth aspect, since the photocatalytic film is formed on at least the surface of the light-transmitting cover that covers the light-receiving surface of the solar cell element, a decrease in the amount of light received due to dirt on the light-transmitting cover is suppressed. Because the photocatalyst film transmits light in a wavelength range longer than that of ultraviolet rays, the solar cell element has high sensitivity and excellent power generation efficiency, and the photocatalyst film blocks the ultraviolet wavelength range. The solar cell element can be protected against ultraviolet rays and the life can be extended.

According to the seventh aspect of the solar cell device, since the photocatalytic film is formed on at least the surface of the light-transmitting cover that covers the light-receiving surface of the solar cell element, the reduction in the amount of light received due to the dirt of the light-transmitting cover is suppressed. Because the photocatalyst film transmits light in a wavelength range longer than that of ultraviolet rays, the solar cell element has high sensitivity and excellent power generation efficiency, and the photocatalyst film blocks the ultraviolet wavelength range. The solar cell element can be protected against ultraviolet rays and the life can be extended. Moreover, if the electromotive force of the solar cell element is stored in the storage battery,
The electric power stored in the storage battery can be used.

The solar cell device according to claim 8 is the solar cell device according to claim 6.
Alternatively, in the solar cell device according to 7, the thickness of the photocatalyst film is 0.01 to 0.5 μm, and if it is less than 0.01 μm, effective photocatalytic activity cannot be expected, and if it exceeds 0.5 μm, the transmittance becomes small. Since the electromotive force cannot be obtained, the optimum range of the film thickness of the photocatalytic film can be set.

A solar cell device according to a ninth aspect is the solar cell device according to the sixth aspect.
In the solar cell device according to any one of 1 to 8, the total transmittance of the photocatalyst film is 90% or more, and if it is less than 90%, a large electromotive force cannot be obtained. Can be set.

According to the solar cell device of claim 10,
In addition to the effect of the solar cell device according to any one of claims 6 to 9, a photocatalyst film is used as anatase crystalline form of titania (T).
The photocatalytic action can be further improved by forming iO ₂ ) as the main component.

According to the solar cell device of claim 11,
In addition to the effect of the solar cell device according to any one of claims 6 to 10, the photocatalyst film is formed through an intermediate layer containing silica (SiO ₂ ) as a main component, and is extracted from the translucent cover. It is possible to prevent the photocatalytic film from being affected and deteriorated by the substance.

According to the illumination system of claim 12,
Since the solar cell element according to any one of claims 1 to 5 is used and the electromotive force of the solar cell element is used in a lighting device, maintenance can be facilitated and stable electromotive force is used with little decrease in electromotive force. it can.

According to the illumination system of claim 13,
Since the solar cell device according to any one of claims 6 to 11 is used and the electromotive force from the solar cell device is used in the lighting device, maintenance can be facilitated and stable electromotive force can be obtained with less reduction in electromotive force. Available.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional view of a solar cell element showing a first embodiment of the present invention.

FIG. 2 is a characteristic diagram of the photocatalyst film and the solar cell substrate of the same embodiment, (a) is a spectral total transmittance characteristic diagram of the photocatalyst film,
(b) is a spectral sensitivity characteristic diagram of the solar cell substrate.

FIG. 3 is a cross-sectional view of a solar cell device showing a second embodiment of the present invention.

FIG. 4 is an enlarged cross-sectional view of a part of the solar cell device according to the third embodiment of the present invention.

FIG. 5 is a side view of the solar cell device according to the above embodiment.

FIG. 6 is an explanatory diagram of a lighting system showing a fourth embodiment of the present invention.

[Explanation of symbols]

 1 solar cell element 2 solar cell substrate 5 light receiving surface 6 photocatalyst film 13 container as a translucent cover 14 solar cell module as a solar cell device 21 solar cell device 22 main body 23 opening 24 translucent cover 26 control circuit 27 storage battery 32 Solar cell device 33 Lighting device 36 Signboard as lighting device 42 Control circuit 43 Storage battery

Claims (13)

[Claims] 1. A solar cell substrate having a light-receiving surface; and a photocatalyst film formed on the light-receiving surface of the solar cell substrate for transmitting light rays in a wavelength range longer than ultraviolet rays and blocking the ultraviolet wavelength range. A solar cell element characterized by being present. 2. The photocatalyst film has a film thickness of 0.01 to 0.5 μm.
The solar cell element according to claim 1, wherein 3. The solar cell element according to claim 1, wherein the total transmittance of the photocatalytic film is 90% or more. 4. The solar cell element according to claim 1, wherein the photocatalytic film is formed mainly of anatase crystalline titania (TiO ₂ ). 5. The solar cell element according to claim 1, wherein the photocatalytic film is formed through an intermediate layer containing silica (SiO ₂ ) as a main component. 6. A solar cell element having a light-receiving surface; a light-transmitting cover that covers the light-receiving surface of the solar cell element; a light-transmitting cover formed on at least the surface of the light-transmitting cover, and transmitting light rays in a wavelength range longer than ultraviolet rays. And a photocatalyst film that blocks the ultraviolet wavelength region; and a solar cell device. 7. A solar cell element having a light-receiving surface; a main body accommodating the solar cell element and having an opening formed so as to face the light-receiving surface of the solar cell element; and a main body so as to cover the light-receiving surface of the solar cell element. A translucent cover attached to the opening of the; a photocatalytic film formed on at least the surface of the translucent cover to transmit light rays in a wavelength range longer than ultraviolet rays and block the ultraviolet wavelength range; housed in the main body A solar cell device comprising: a control circuit for controlling electromotive force from the solar cell element; and a storage battery housed in the main body. 8. The photocatalyst film has a film thickness of 0.01 to 0.5 μm.
The solar cell device according to claim 6 or 7, wherein 9. The solar cell device according to claim 6, wherein the photocatalytic film has a total transmittance of 90% or more. 10. The solar cell device according to claim 6, wherein the photocatalyst film is formed mainly of anatase crystal type titania (TiO ₂ ). 11. The solar cell device according to claim 6, wherein the photocatalytic film is formed via an intermediate layer containing silica (SiO ₂ ) as a main component. 12. A lighting system comprising: the solar cell element according to any one of claims 1 to 5; and a lighting device using an electromotive force of the solar cell element. 13. A lighting system comprising: the solar cell device according to claim 6; and a lighting device that utilizes electromotive force from the solar cell device.