JPH05218471A - Manufacture of thin-film solar cell device - Google Patents

Abstract

PURPOSE:To enable a thin film formed on a flexible insulating substrate to be evenly worked with a laser beam at patterning even if the substrate deteriorates in evenness due to the stress of the thin film. CONSTITUTION:A transparent flexible insulating board 1 where a thin film is formed is sandwiched between transparent correcting plates 51 and 52 possessed of smooth surfaces to be improved in evenness, and the thin film formed on the substrate 1 is worked by irradiation with laser rays through the correcting plates 51 ad 52 and the flexible insulating board 1, whereby the board 1 is divided into solar unit cells which are connected together in series.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thin film solar cell device in which unit cells of a solar cell formed on a flexible substrate and using a thin film semiconductor containing amorphous silicon as a main component are connected in series. Regarding the method.

[0002]

2. Description of the Related Art An amorphous semiconductor thin film formed by glow discharge decomposition of a raw material gas or optical CVD can be easily formed on a flexible substrate such as a polymer material because the film is formed at a low temperature. .. Therefore, it is expected as a material for a solar cell to be installed on a house building material, an automobile sunroof, or any other object having a curved surface. In order to efficiently extract the power generated from such amorphous solar cells,
For example, the solar cell device has a shape as shown in FIG.
A structure in which the unit cells are connected in series is desirable.
This structure has a first electrode having transparency and conductivity in the power generation wavelength region of a solar cell made of SnO ₂ , ZnO or the like on a flexible insulating substrate 1 such as a polymer material having transparency. Layer 2
1, 22, 23 is formed in a strip shape, the amorphous semiconductor layer 31, 32, 33 is a photovoltaic generation portion on it, then the second electrode layer 41 consisting of a light-transmitting / conductive thin film or a metal thin film, 42, 43
Are sequentially stacked. Then, the patterns of both electrode layers and the amorphous semiconductor layer are configured so that the first electrode layer of one unit cell partially contacts the second electrode layer of the adjacent unit cell. Such a pattern of each layer is formed by patterning a thin film formed over the entire surface by a laser patterning method.

[0003]

In order to manufacture a thin film solar cell device connected in series as shown in FIG. 2, patterning is required three times. It is a first electrode patterning that forms a plurality of electrically separated first electrode layers by dividing the translucent / conductive thin film into strips, and forms a gap that can connect the first electrode layer and the second electrode layer. In order to achieve this, an amorphous patterning for dividing the amorphous semiconductor thin film and a second electrode patterning for dividing the second electrode layer to electrically separate the unit cells are performed. However, when a flexible substrate is used, the flatness of the flexible substrate deteriorates due to the stress of each layer caused by the formation of the first and second electrode layers or the amorphous semiconductor thin film on the flexible substrate. As shown in FIG. 3, if the laser processing point shifts from the reference point in the lens direction, the laser energy density on the film surface to be processed increases, and if it shifts to the XY stage side that supports the substrate, the laser energy density decreases. Become. Therefore, if the flatness of the flexible substrate is deteriorated, the processing uniformity of laser patterning is reduced, and the dimensional accuracy of each unit cell is reduced, or electrical isolation between individual unit cells or incomplete electrical connection occurs. there were.

An object of the present invention is to solve the above problems and to manufacture a thin film solar cell device which uniformly processes a thin film on a flexible substrate whose flatness is lost due to stress during the formation of each layer by laser. To provide a method.

[0005]

In order to achieve the above object, the present invention provides a first thin film formed by dividing a thin film formed on a light-transmissive flexible insulating substrate. In a method for manufacturing a thin film solar cell in which unit cells having an amorphous semiconductor layer are connected in series between second electrode layers, between the smooth surfaces of two translucent straightening plates, at least one surface of which is a smooth surface after thin film formation. The flexible insulating substrate is sandwiched and fixed, and the thin film is processed and divided by irradiating a laser beam through the straightening plate and the flexible insulating substrate. At that time, it is effective that the wavelength of the laser light projected to process the amorphous semiconductor layer and the second electrode layer is shorter than the wavelength of the laser light projected to process the first electrode layer. Further, it is effective to install the flexible substrate and the correction plate on an XY stage which can be moved in a vertical plane in the laser beam projection direction by computer control during processing by laser beam projection.

[0006]

[Function] The flatness of the flexible substrate is improved by sandwiching and fixing the flexible substrate from both sides with a transparent correction plate such as glass having a smooth surface on the surface in contact with the flexible substrate,
This improves the processing uniformity of laser patterning by the laser light projected through the straightening plate.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of the present invention will be described with reference to the drawing in which the same parts as those in FIG. Figure 1
X when laser patterning a thin film on a flexible substrate
It shows how to attach to the Y stage. In the process before this, a ZnO film having a thickness of 1 μm was formed as the first electrode layers 21, 22 and 23 on the flexible insulating substrate 1 such as a polymer material, and then an amorphous semiconductor (amorphous silicon) was formed.
The layers 31, 32, 33 are formed with a thickness of 0.4 μm. The first electrode layer and the amorphous semiconductor layer were patterned by the same laser scribing method as the conventional one. A YAG: Na laser having a wavelength of 1.06 μm is used as a laser light source for patterning the first electrode layers 21, 22, and 23, and a YAG: Nd having a wavelength of 0.53 μm is used as a light source for patterning the amorphous semiconductor layers 31, 32, and 33. Using each laser,
It was projected from the side of the flexible substrate 1. Then, a silver thin film 40 for the second electrode layer was formed thereon with a thickness of 0.2 μm. Then, as shown in the figure, the flexible substrate 1 whose flatness was poor by being sandwiched by the straightening glass plates 51 and 52 from both sides was fixed so as to be flat, and placed on the XY stage 6. At the time of patterning, the XY stage 6 takes arbitrary coordinates by computer control.

As a laser light source, YA having a wavelength of 0.53 μm
A G: Nd laser is used, and the laser light 7 is also incident from the flexible substrate 1 side. In this case, the laser light 7 is transmitted through the transparent straightening glass plate 51 and the flexible substrate 1 and is not absorbed by the first electrode layers 21, 22, 23 because it has a short wavelength, and is absorbed by the silver thin film 40. Since the material of this film is evaporated, XY
The portion 8 shown by the dotted line in the figure is controlled by the movement of the stage 6.
Are removed.

By using the straightening glass plates 51 and 52 as described above, the flatness, which is a problem of the flexible substrate, is shown in FIG.
It was controlled within ± 500 μm shown by A. As a result, variations in laser energy density during processing can be kept within ± 0.1, and laser patterning with good uniformity can be performed. As a result, it was possible to obtain a high-performance series-connected thin-film solar cell having flexibility.

In the above embodiments, the straightening glass plate was used only when patterning the second electrode layer, but depending on the degree of flatness of the flexible substrate after the first electrode layer or the amorphous semiconductor layer is formed. It is also effective to sandwich the glass plate for correction during patterning of the first electrode layer or during patterning of the amorphous semiconductor layer.

[0011]

According to the present invention, patterning for forming a thin film solar cell unit cell connected in series from a first electrode layer, an amorphous layer and a second electrode layer formed on a flexible insulating substrate. At this time, at least one flexible substrate is sandwiched between two translucent plates to perform laser processing in a state where the flatness is improved, whereby the processing uniformity of laser patterning is improved and accurate patterning is performed. I was able to do it. As a result, it has become possible to manufacture thin film solar cell devices with high performance that can be installed on curved surfaces.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a second electrode layer patterning step according to an embodiment of the present invention.

2 is a cross-sectional view of a thin-film solar cell device manufactured through the steps shown in FIG.

FIG. 3 is a relationship curve diagram of a laser energy density at a processing point and a deviation of a processing point from a reference point during laser processing.

[Explanation of symbols]

 1 Flexible Insulating Substrate 21 First Electrode Layer 22 Second Electrode Layer 23 Third Electrode Layer 31 Amorphous Semiconductor Layer 32 Amorphous Semiconductor Layer 33 Amorphous Semiconductor Layer 40 Silver Thin Film 41 Second Electrode Layer 42 Second Electrode Layer 43 Second Electrode Layer 51 Straightening Glass Plate 52 Straightening Glass Plate 6 XY Stage 7 Laser Light 8 Laser Processing Section

Claims (3)

[Claims] 1. A unit cell having an amorphous semiconductor layer between first and second electrode layers, which is formed by dividing a thin film formed on a transparent flexible insulating substrate, is connected in series. In the method of manufacturing a thin film solar cell, the flexible insulating substrate is sandwiched between the smooth surfaces of two light transmissive straightening plates having at least one smooth surface after the thin film is formed. A method for manufacturing a thin-film solar cell device, which comprises processing and dividing a thin film by irradiating a laser beam through a flexible insulating substrate. 2. The thin film solar cell according to claim 1, wherein the wavelength of laser light projected to process the amorphous semiconductor layer and the second electrode layer is shorter than the wavelength of laser light projected to process the first electrode layer. Device manufacturing method. 3. The thin film solar cell device according to claim 1, wherein the flexible substrate and the straightening plate are installed on an XY stage which can be moved in a plane vertical to the laser beam projection direction by computer control during processing by laser beam projection. Manufacturing method.