JPH08181339A - Flexible solar cell module - Google Patents

Abstract

PURPOSE: To provide a solar cell which is excellent in weatherability, thermal resistance, water resistance and moisture resistance by forming a weatherable protective film which covers a thin film optical conversion device formed on a flexible board with an inorganic insulation layer which is small in vapor permeability and low in cost inside and an organic insulation film outside. CONSTITUTION: A reflective electrode layer 4, a photoelectric conversion layer 3 and a transparent electrode layer 2 are laminated one after another on one surface of an insulated film 1 of a base material, thereby forming a thin film photoelectric conversion device having a serial connection structure. The front surface and the side surfaces of the conversion device is covered with a transparent and insulating thin film 5. The rear surface and the side surfaces of the film 1 are covered with a low cost inorganic insulating thin film 7 which is small vapor permeability, but the formation surfaces of the terminal electrode layers 61 and 62 are excluded. The terminal electrodes 61 and 62 are connected with a lead wire and then a terminal 10 on the end of the lead wire is exposed so that it may be covered with the organic insulation film 9. This construction makes it possible to provide a low cost solar cell module which is excellent in weatherability and thermal resistance and moisture resistance without degrading flexibility.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flexible solar cell module using a plurality of thin film photoelectric conversion elements each having a thin film photoelectric conversion layer formed on a flexible insulating substrate together with an electrode layer.

[0002]

2. Description of the Related Art A general thin film solar cell module includes a plurality of thin film photoelectric conversion elements having a serial connection structure in which a transparent electrode, a photoelectric conversion layer, and a reflective metal electrode are sequentially laminated on a transparent insulating substrate. And the weather resistant film is adhesively sealed with an insulating adhesive resin. When a glass plate is used as a transparent insulating base material, although it does not have flexibility, the base material itself is chemically stable and has excellent weather resistance such as water resistance, moisture resistance, and heat resistance. As shown in 3,
A transparent electrode layer 2, a photoelectric conversion layer 3, and a reflective electrode layer 4 are sequentially laminated with the surface of the glass substrate 11 as a light incident side to form a photoelectric conversion element, and a metal foil is formed inside the element formation surface side and has excellent weather resistance. It suffices to bond the weather resistant film 13 and the like that it has with the insulating sealing material 12. When a conductive substrate that is not translucent, such as a stainless steel plate, is used as the base material, the surface opposite to the light incident side becomes a chemically stable base material. For example, as shown in FIG. A reflective electrode layer 4, a photoelectric conversion layer 3, and a transparent electrode layer 2 are sequentially laminated on 14 to form a photoelectric conversion element, and a light-transmitting and weather-resistant film 15 made of a fluororesin is formed on the light-incident side. The insulating sealing material 16 adheres to improve the weather resistance of the module.

When the transparent resin film 17 having high flexibility is used as the insulating base material, the weather resistance of the base material itself is extremely inferior to that of glass or stainless steel. Therefore, as shown in FIG. The substrate on which the photoelectric conversion element having the same structure as that of No. 3 is formed is covered with a fluorine resin film 15 on the light incident side, and the opposite surface is covered with a weather resistant film 13 containing a metal foil to form a module. Similarly, in the case where the photoelectric conversion element has a structure in which the transparent electrode layer 2 is formed on the side far from the base material as shown in FIG. 4, both surfaces need to be covered with a weather resistant film.

[0004]

As shown in FIG. 4, when an expensive fluororesin film or a metal foil-containing weather resistant film is used on both sides, it is difficult to reduce the cost of the solar cell module. In addition, there is a problem that flexibility is impaired. If you cover both sides with a low cost film, heat resistance,
Water resistance and moisture resistance are not sufficient, and permeation of water vapor cannot be completely suppressed.

An object of the present invention is to solve the above-mentioned problems and to provide a flexible solar cell module which has high performance and high reliability while being low in cost.

[0006]

In order to achieve the above-mentioned object, the present invention provides a plurality of thin film photoelectric conversion elements connected to each other on a flexible insulating substrate, both surfaces of which have terminal portions. Except for at least the light incident side, in a flexible solar cell module covered with a translucent weatherproof protective coating, the protective coating is made of an inorganic insulating thin film on the side close to the photoelectric conversion element or the substrate, and is exposed to the outside air The side is made of an organic insulating layer. It is preferable that the inorganic insulating thin film on the light incident side is made of any one of SiOx, SiNx and SiOxNy, and the value of x or x + y is 1 or more. It is preferable that the insulating thin film on the side opposite to the incident light is made of any one of oxides and nitrides of Si, Ti, Ta and Al. The thickness of the inorganic insulating thin film covering the photoelectric conversion element side is 3
It is preferably 0 to 150 nm. The organic insulating layer is preferably made of any one of silicone, polyimide, polyimideamide, and fluorine resins.

[0007]

The inorganic insulating thin film has a low water vapor permeability and a low price. By using this together with an organic insulating layer which is easy to obtain surface smoothness, a protective film coating having excellent heat resistance, water resistance and moisture resistance can be obtained. SiOx, SiNx or SiOx is applied to the translucent insulating film on the light incident side.
When Ny is used, it is desirable that the value of x or x + y is 1 or more, because visible light, particularly light having a wavelength of 300 to 500 nm is absorbed as oxygen or nitrogen in the film decreases. Any of oxides or nitrides of Si, Ti, Ta, and Al is used for the insulating film that does not need to have a light-transmitting property.
The water vapor permeability of the inorganic insulating thin film covering the photoelectric conversion element side should be thicker, but the stress acting on the element increases as the film thickness increases, so the thickness should be in the range of 30 to 150 nm. Is suitable. As the organic insulating material covering the surface, a silicone-based, polyimide-based, polyimideamide-based, or fluorine-based resin having good weather resistance is used.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described below with reference to the drawings in which the same parts as those in FIGS. 1 and 2 are a horizontal cross-sectional view and a vertical cross-sectional view of a solar cell module according to an embodiment of the present invention, in which a reflective electrode layer 4, a photoelectric conversion layer 3, and a transparent electrode are provided on one surface of an insulating film 1 as a base material. A thin film photoelectric conversion element having a series connection structure in which layers 4 are sequentially stacked is formed. The surface and side surfaces of this element are covered with a transparent insulating thin film 5. Film 2
On the other surface, a positive terminal electrode 61 and a negative terminal electrode 62 are formed at both ends of the thin film photoelectric conversion element. The back surface and side surfaces of the film 1 other than the surface on which the terminal electrode layers 61 and 62 are formed are covered with the insulating thin film 7. The insulating thin film 7 may expose the terminal electrode layers 61 and 62 entirely as shown in the drawing, or may cover a part thereof. Transparent insulating thin film 5
And the plurality of photoelectric conversion elements covered with the insulating thin film 7,
After connecting the terminal electrodes 61 and 62 with the lead wire 8, the terminal 10 at the end of the lead wire is exposed and covered with the organic insulating film 9.

The transparent insulating thin film 5 is made of an inorganic substance such as SiOx,
The main component is SiNx, SiOx Ny, etc., and it is formed by the sputtering method. The thin film 5 plays a role of preventing invasion of water vapor from the light incident side of the photoelectric conversion element. FIG. 6 shows that the water vapor transmission rate is 106 g / m ² / d.
ay and high shows the film thickness dependence of the water vapor permeability of the SiOx film formed on the polyether sulfone (PES). As is clear from the figure, the water vapor transmission rate is drastically reduced when the film thickness is 10 nm or more. However, since the stress acting on the element increases as the thickness of the insulating thin film increases, the thickness of the insulating thin film 5 is preferably about 30 to 150 nm. Further, since the film composition absorbs visible light, particularly light having a wavelength of 300 to 500 nm with a decrease in oxygen or nitrogen in the film, when the film is made of SiOx, SiNx, or SiOx Ny, x or x + y It is desirable that the value is 1 or more.

The insulating thin film 7 on the back surface side of the base material 1 does not need to be translucent, and may be an oxide film or a nitride film of Si, Ti, Ta, Al, and may be a vapor deposition method, a sputtering method or a C method.
It is formed by the VD method or by coating and baking. Although the terminal electrode layers 61 and 62 project from the insulating thin film 7 in the figure, they may be recessed. The inorganic insulating thin film 7 plays a role of preventing the invasion of water vapor from the substrate surface side, and the film thickness may be 10 nm or more if it is a Si-based oxide film. The exposure of the terminal electrode layers 61 and 62 is performed by the lead wire 8
It is necessary to connect the photoelectric conversion elements by using, and it is exposed by etching after forming the insulating film 7 or by covering the surface with a masking tape or a treatment liquid that can be peeled in advance. When a peeling tape or the like is used, burrs are generated due to peeling, but since it is covered with the organic insulating film 9, it is possible to suppress deterioration of the characteristics and reliability of the element itself.

After connecting a plurality of photoelectric conversion elements covered with inorganic insulating films 6 and 7 using lead wires 8, a portion other than the terminals 10 of the module was covered with ethylene vinyl acetate (EVA) film and laminated. After that, the organic insulating film 9 is formed by crosslinking. Polyamideimide resin, fluorine resin, silicone resin, or a mixture thereof may be used for the insulating film 9 in addition to EVA, and is formed by coating and baking.

In the above embodiment, light is incident from above the thin film photoelectric conversion element formed on the base material. However, a translucent base material is used, and a solar cell module in which light is incident from the base material side is used. Can also be implemented. In that case, film 1
It is not necessary to make the insulating thin film 7 on the back surface of the device transparent and the insulating thin film 5 covering the element to be transparent.

[0013]

According to the present invention, a weather-resistant protective coating for covering a thin film photoelectric conversion element formed on a flexible substrate is provided, which is a low-cost inorganic insulating thin film having a low water vapor permeability inside.
By forming the outer side with the organic insulating layer, it was possible to obtain a solar cell module excellent in weather resistance, heat resistance, water resistance and moisture resistance at low cost without impairing flexibility.

[Brief description of drawings]

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

FIG. 2 is a vertical cross-sectional view of the solar cell module shown in FIG.

FIG. 3 is a cross-sectional view of an example of a conventional thin film photoelectric conversion element.

FIG. 4 is a cross-sectional view of another example of a conventional thin film photoelectric conversion element.

FIG. 5 is a cross-sectional view of still another example of a conventional thin film photoelectric conversion element.

FIG. 6 is a diagram showing the relationship between the water vapor transmission rate and the thickness of a SiOx film.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Insulating film 2 Transparent electrode layer 3 Photoelectric conversion layer 4 Reflective electrode layer 5 Transparent insulating thin film 61 Positive terminal electrode layer 62 Negative terminal electrode layer 7 Insulating thin film 8 Lead wire 9 Insulating film

Claims (5)

[Claims] 1. A plurality of thin-film photoelectric conversion elements connected to each other are formed on a flexible insulating substrate, and a weather-resistant protective film is formed on both sides of which at least a light-incident side is translucent except a terminal portion. In the covered one, the protective coating is made of an inorganic insulating thin film on the side close to the photoelectric conversion element or the substrate,
A flexible solar cell module, characterized in that the side in contact with the outside air is composed of an organic insulating layer. 2. An inorganic insulating thin film on the light incident side is SiOx,
The flexible solar cell module according to claim 1, which is made of either SiNx or SiOxNy and has a value of x or x + y of 1 or more. 3. The inorganic insulating thin film on the side of incident light is Si, T
The flexible solar cell module according to claim 1 or 2, which is made of any one of oxides and nitrides of i, Ta and Al. 4. The flexible solar cell module according to claim 1, wherein the inorganic insulating thin film covering the photoelectric conversion element side has a thickness of 30 to 150 nm. 5. The flexible solar cell module according to claim 1, wherein the organic insulating layer is made of any one of silicone, polyimide, polyimideamide and fluorine resins.