JP2001102603A - Thin film solar cell and method of manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thin-film solar cell that allows a part of incident light to pass therethrough and a method for manufacturing the thin-film solar cell without complicating the manufacturing process as compared with the related art. SOLUTION: An insulating translucent substrate 1, a transparent conductive film 2, and
An integrated thin-film solar cell including a photoelectric conversion film 3 made of an amorphous silicon-based semiconductor and a back electrode film 50, divided into a plurality of power generation regions on an insulated translucent substrate 1, and connected in series. , Resist film 6 laminated on back electrode film 50
And a back electrode film separation line 9 that is patterned into substantially the same shape through the resist film 6, the back electrode film 50, and the photoelectric conversion film 3, and the resist film 6, the back electrode film 50, and the A light-transmitting opening 10 formed by partially removing the conversion film 3.

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 and a method of manufacturing the same, and more particularly, to a thin-film solar cell that transmits a part of incident light and a method of manufacturing the same.

[0002]

2. Description of the Related Art Conventionally, as an example of the structure of a thin-film solar cell, SnO ₂ , IT
A transparent conductive film such as O or ZnO is formed, and a p-layer, an i-layer, and an n-layer of an amorphous semiconductor are stacked in this order to form a photoelectric conversion layer, and further, ITO,
In some structures, a back electrode film is formed by laminating a transparent electrode such as ZnO and a metal electrode film such as Ag and Al in this order. Further, as another example, a transparent electrode such as ITO or ZnO is formed on a metal substrate, and an n layer of an amorphous silicon-based semiconductor, i.
In some structures, a photoelectric conversion film is formed by laminating a layer and a p-layer in this order, and a transparent conductive film such as SnO ₂ , ITO, or ZnO is formed thereon.

[0003] Of these, in a thin-film solar cell formed on an insulated translucent substrate such as glass, in order to form a transmissive part that allows a part of incident light to pass through, a part of the photoelectric conversion film must be formed on the photoelectric conversion film. A method using a so-called mask process in which a back electrode film is formed and a portion of the photoelectric conversion film exposed from the back electrode film is removed by etching using the back electrode film as a mask has been the mainstream of the conventional manufacturing method.

[0004]

However, according to the above-mentioned conventional method, there is a problem that the number of management items in the process increases for the alignment of the mask when forming the back electrode film and the improvement of accuracy. Was. In addition, in the vicinity of the incident light transmitting portion, there is a problem that the characteristic distribution of the thin film solar cell becomes non-uniform due to the deterioration of the film quality distribution of the back electrode film. Furthermore, with an increase in the number of photoelectric conversion film etching steps,
There is also a problem that the manufacturing process is complicated.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned conventional problems and to manufacture a thin-film solar cell that allows a part of incident light to pass therethrough and to manufacture the thin-film solar cell without complicating the manufacturing process as compared with the conventional one. It is to provide a method that can be performed.

[0006]

A thin-film solar cell according to the present invention comprises an insulating translucent substrate, a transparent conductive film, a photoelectric conversion film made of an amorphous silicon-based semiconductor, and a back electrode film. An integrated thin-film solar cell divided into a plurality of power generation regions on a light-transmitting substrate and connected in series, wherein a resist film laminated on a back electrode film, a resist film, a back electrode film, and a photoelectric conversion film And a light-transmitting opening formed by partially removing the resist film, the back electrode film, and the photoelectric conversion film in the power generation region. Have.

According to the present invention, the resist film, the back electrode film and the photoelectric conversion film in the power generation region are partially removed,
That portion is a light-transmitting opening. As a result, part of the light incident from the insulating translucent substrate side of the thin-film solar cell,
It can be transmitted to the back side.

Preferably, the light-transmitting opening has a linear shape parallel to the back electrode film separation line.

For example, by injecting an etching solution from a nozzle swung in the direction of the back electrode film separation line,
The patterning residue of the back electrode film separation line and the light-transmitting opening having a linear shape parallel to the back electrode film separation line can be easily removed by etching.

[0010] Preferably, the light-transmitting opening having a linear shape has a discontinuous line shape.

According to the present invention, the light-transmitting opening is distinguished from the back electrode film separation line formed in a linear continuous line shape, and the back electrode film is separated in the power generation region to be electrically operated. It is possible to prevent a structure in a non-connected state from being obtained.

Preferably, a plurality of discontinuous line-shaped translucent openings are formed in the power generation region.

As described above, the aperture ratio of the light-transmitting openings is arbitrarily set by forming the plurality of linear light-transmitting openings in the discontinuous line shape in the power generation region. Can be.

[0014] Preferably, the plurality of discontinuous line-shaped translucent openings are formed at equal intervals in the power generation region.

As described above, since a plurality of linear and discontinuous line-shaped light-transmitting openings are formed in the power generation region at the same interval, uniform light transmission can be obtained.

Preferably, the resist film surface side is coated with a light-transmitting back surface sealing material so that a part of light incident from the insulating light-transmitting substrate side can be seen from the back surface side of the thin-film solar cell. .

As described above, the use of the light-transmitting back surface sealing material prevents moisture and the like from entering from the back surface, is excellent in weather resistance, and is a part of light incident from the insulating light-transmitting substrate side. Can be transmitted to the back surface side to obtain a thin-film solar cell.

As the light-transmitting back surface sealing material, for example, a fluorine resin, glass, or the like can be used.

The method for manufacturing a thin-film solar cell according to the present invention comprises:
A method for manufacturing a thin-film solar cell according to the present invention as described above, wherein the light-transmitting opening is formed by processing using laser light.

As described above, by processing with a laser beam, a back electrode film separation line formed in a linear continuous line shape and a light-transmitting opening can be simultaneously processed in one step. .

As an example, the light-transmitting opening can be formed in a discontinuous line shape by performing ON / OFF control of an oscillator that emits a laser beam depending on the processing coordinate position.

According to such a method, the back electrode film separation line formed in a linear continuous line shape and the translucent opening formed in a linear discontinuous line shape are simultaneously formed in one step. Can be processed.

Further, as still another example, a shutter is provided in the optical path of the laser beam, and the opening / closing control of the shutter is performed depending on the processing coordinate position, so that the light-transmitting opening is formed in a discontinuous line. It can also be formed in a shape.

According to such a method, the back electrode film separation line formed in a linear continuous line shape and the translucent opening formed in a linear discontinuous line shape can be simultaneously formed in one step. Can be processed.

The shutter includes a mechanical shutter, an electro-optical shutter, and an acousto-optical shutter.

Further, as another example, a light-transmitting opening can be formed in a discontinuous line shape by setting a mask on an insulating light-transmitting substrate and processing it using laser light.

When a laser beam is used for processing, a mask is provided on the insulating and translucent substrate, so that the laser beam can be shielded at a portion where the mask is provided.

[0028]

1 to 3 are views for explaining a method of manufacturing an example of a thin-film solar cell according to the present invention.

Referring to FIG. 1, first, a transparent conductive film 2 is formed in advance.
Is used. On the glass substrate 1, a transparent conductive film 2 is formed on one side surface and the entire peripheral end surface of the glass substrate 1.

Next, the transparent conductive film is patterned using a laser beam. At this time, for example, using a YAG fundamental wave laser beam or the like that is well absorbed by the transparent conductive film 2 and the laser beam is incident from the glass substrate 1 side, the transparent conductive film 2 is separated into strips, and Electrode membrane separation line 7
Is formed.

Subsequently, the glass substrate 1 on which the transparent conductive film 2 is formed is washed with pure water to form a photoelectric conversion film 3. The photoelectric conversion film 3 includes an Hp layer, a Hi layer, and a Hn layer, and has a total thickness of 100 nm to 600 nm.

Next, only the photoelectric conversion film 3 is patterned using a laser beam. At this time, in order to avoid damage to the transparent conductive film 2 due to the laser light, the photoelectric conversion film 3 is separated into strips by using a wavelength-selective, for example, a YAG SHG laser or the like and making it incident from the glass substrate 1 side. Thus, the photoelectric conversion film separation line 8 is formed. This photoelectric conversion film separation line 8 is approximately 50
It is formed with a width of 50 μm to 100 μm at a position overlapping about μm or at a distance of about 50 μm.

Subsequently, a back electrode film 50 is formed by laminating the transparent electrode film 4 and the metal electrode film 5. The transparent electrode film 4 has low specific resistance and high translucency.
For example, ZnO or ITO is used. On the other hand, for the metal electrode film 5, for example, Al or Ag having high reflectivity is used. The thickness of the transparent electrode film 4 is about 50 nm to 200 nm, and the thickness of the metal electrode film 5 is about 500 nm to 1 μm. However, the transparent electrode film 4 may be omitted.

Next, a resin film to be the resist film 6 is applied on the back electrode film 50 to a thickness of several μm to several tens μm and dried. At the time of application, in order to form a thin and uniform film thickness, for example, application is performed by a spin coater, a spray method or the like, and after application, the coating is dried in a drying furnace or the like. Further, the back electrode film 50 is patterned using laser light. At this time, in order to prevent the transparent conductive film 2 from being damaged by the laser beam,
At the same time, in order to remove the photoelectric conversion film 3, wavelength-selective, for example, a YAG SHG laser or the like is used and the light is incident from the glass substrate 1 side, so that the back electrode film 50 is removed.
Are separated into strips, and at the same time, the photoelectric conversion film 3 is also removed, so that the back electrode film separation line 9 is formed. This back electrode film separation line 9 is different from the photoelectric conversion separation line 8 by about 50 μm.
at a distance of about 1 to 150 μm
It is formed with a width of 50 μm to 100 μm.

As described above, at least the insulating translucent substrate 1, the transparent conductive film 2, the photoelectric conversion film 3 made of an amorphous silicon-based semiconductor, and the back electrode film 50 are formed on the insulating translucent substrate 1. In the integrated thin-film solar cell divided into power generation regions and connected in series, a resist film 6 is laminated on the back electrode film 50, and the back electrode film separation line 9 is formed by the resist film 6, the back electrode film 50 and the photoelectric conversion film. 3 can be obtained as a thin-film solar cell patterned into substantially the same shape.

Next, the light-transmitting openings 10 are patterned in the power generation region. At this time, in order to prevent the transparent conductive film 2 from being damaged by the laser beam and to remove the photoelectric conversion film 3 at the same time, a wavelength-selective material such as YAG S
Using a HG laser or the like, the light-transmitting opening 10 is formed by making the light enter from the glass substrate 1 side. The translucent opening 10 has a linear shape parallel to the back electrode film separation line 9 and must have a discontinuous line shape. If the light-transmitting opening 10 has a continuous line shape, the light-transmitting opening 10 is formed within the power generation region in the back electrode film 5.
This is because 0 is separated and becomes electrically disconnected. In order to avoid this situation, a mask 20 is provided on the insulated translucent substrate 1 so as not to separate the power generation region, and processing is performed using laser light.

FIG. 2 is a plan view showing an example of a mask used for forming a light-transmitting opening in the present invention.

Referring to FIG. 2, this mask 20 has a length of 10 mm to 116 mm, 1 mm from the longitudinal end of the power generation region.
36mm to 242mm, 262mm to 368m
m, 388 mm to 494 mm, 514 mm to 6
A mask that can be processed at a position of 20 mm.

Using this mask 20, a width of 7.08 mm
In the power generation area divided into strips, ten light-transmitting openings 10 are formed at a pitch of about 0.064 mm to 0.065 mm in parallel with the back electrode film separation line 9 with a width of 0.08 mm.

FIG. 3 is a sectional view showing a schematic configuration of an example of the thin-film solar cell according to the present invention obtained in this way.

In the above-described example, the light-transmitting openings 10 are formed.
Is formed by using a YAG SHG laser using a mask, but the formation of the translucent opening is not limited to the method using the mask. As a method without using a mask, for example, processing with the laser light in which ON / OFF of the oscillation of the oscillator for emitting the laser light is controlled by a processing coordinate position, or a mechanical shutter is provided in an optical path of the laser light, and the mechanical shutter is provided. Processing using the laser light in which the opening / closing of the shutter is controlled by the processing coordinate position may be performed. Also, instead of a mechanical shutter, an electro-optical (M
An O) element or a shutter using an acousto-optic (AO) element may be used. If these processes are employed, there is also an advantage that the process of the back electrode film separation line 9 and the process of the translucent opening 10 can be performed simultaneously in one step.

The data used to form the light-transmitting opening is not limited to the YAG SHG laser. For example, processing with a YAG fundamental wave laser or the like may be used.

Further, in the above-described example, the light-transmitting openings in the power generation region have independent structures for uniform lighting. However, from the viewpoint of preventing the occurrence of a short circuit with the surface electrode due to the patterning residue. This is not always the best condition because the extension distance of the outer periphery of the opening becomes long. In order to reduce this, the length of the outer periphery of the opening may be reduced with respect to the opening area by making the adjacent light-transmitting openings contact or overlap each other.

FIG. 4 is a sectional view showing a schematic structure of the thin-film solar cell according to the present invention thus formed.

Finally, after the formation of the light-transmitting opening 10, residues of the back electrode film 2 remain around the light-transmitting opening 10 due to processing defects or the like. There is a possibility that a short circuit occurs between the back electrode films 50 in the region or a short circuit occurs between the transparent conductive film 2 and the back electrode film 50 in one power generation region. Therefore, the residue is removed by etching. As the etchant, a solution that can be used as an etchant for the back electrode film 50 is used.

In this example, since ZnO as the transparent electrode film 4 and Ag as the metal electrode film 5 are used for the back electrode film 50, an acid-based etchant and an Ag-based For etching, an iron sulfate-based etchant is used.

FIG. 5 is a view showing the swinging direction of the nozzle from the etching pump of the etching apparatus used in this example.

Referring to FIG. 5, the swing direction of the nozzle is parallel to the back electrode film separation line, that is, it is also parallel to the light-transmitting opening which is a linear discontinuous line shape. It is possible to remove residues by etching due to surface tension or the like.

In the above-described example, the photoelectric conversion layer has a single structure, but may have a stacked structure such as a tandem structure or a triple structure.

When the thin-film solar cell manufactured as described above is made into a module, a part of light incident from the insulated translucent substrate side can be seen from the back side of the thin-film solar cell. In order to increase the humidity, a light-transmitting back surface sealing material may be attached to prevent moisture. At this time, the back sealing material
A fluorine resin or glass is used. The integrated thin-film solar cell module manufactured by this method transmits a part of incident light, and can be manufactured without complicating the manufacturing process as compared with the conventional manufacturing method.

[0051]

EXAMPLES According to the above-described embodiment, a thin-film solar cell was actually manufactured.

In a 60-stage integrated thin-film solar cell, 600
The translucent openings 10 of the book were patterned to obtain an aperture ratio of 9.7%. The characteristics of the integrated thin-film solar cell (substrate size: 650 mm × 455 mm) manufactured by this method were measured by AM
At 1.5 (100 mW / cm ² ), the short-circuit photocurrent I
sc = 0.546 [A], open-end voltage Voc = 54.2
37 [V], fill factor F.I. F. = 0.608, and the optimum operating point output Pmax was 18.017 [W].

[0053]

As described above, the thin-film solar cell manufactured according to the present invention and the method for manufacturing the same produce a thin-film solar cell that allows a part of incident light to pass through without complicating the manufacturing process. be able to.

[Brief description of the drawings]

FIG. 1 is a diagram for explaining a method of manufacturing an example of a thin-film solar cell according to the present invention.

FIG. 2 is a diagram illustrating a method for manufacturing an example of a thin-film solar cell according to the present invention.

FIG. 3 is a diagram for explaining a method of manufacturing an example of a thin-film solar cell according to the present invention.

FIG. 4 is a cross-sectional view showing a schematic configuration of another example of the thin-film solar cell according to the present invention.

FIG. 5 is a diagram showing a swinging direction of a nozzle from an etching pump of an etching apparatus used in the method of manufacturing a thin-film solar cell according to the present invention.

[Explanation of symbols]

1 glass substrate, 2 transparent conductive film, 3 photoelectric conversion film, 4
Transparent electrode film, 5 metal electrode film, 6 resist film, 7
Transparent conductive film separation line, 8 Photoelectric conversion film separation line, 9
Back electrode film separation line, 10 translucent opening, 20
Mask, 50 back electrode film. In the drawings, the same reference numerals indicate the same or corresponding parts.

Claims (12)

[Claims] An insulating light-transmitting substrate, a transparent conductive film, a photoelectric conversion film made of an amorphous silicon-based semiconductor, and a back electrode film, wherein a plurality of power generation regions are formed on the insulating light-transmitting substrate. An integrated thin-film solar cell that is divided and connected in series, and has substantially the same shape as a resist film laminated on the back electrode film, penetrating the resist film, the back electrode film, and the photoelectric conversion film. A thin film comprising: a back electrode film separation line patterned into a; a resist film in the power generation region, the back electrode film, and a light-transmitting opening formed by partially removing the photoelectric conversion film. Solar cells. 2. The thin-film solar cell according to claim 1, wherein the light-transmitting opening has a linear shape parallel to the back electrode film separation line. 3. The thin-film solar cell according to claim 2, wherein the light-transmitting opening having a linear shape has a discontinuous line shape. 4. The thin-film solar cell according to claim 3, wherein a plurality of the discontinuous line-shaped transparent openings are formed in the power generation region. 5. The thin-film solar cell according to claim 4, wherein the plurality of discontinuous line-shaped translucent openings are formed in the power generation region at equal intervals. 6. The resist film surface side is coated with a light-transmitting back surface sealing material so that a part of light incident from the insulating light-transmitting substrate side can be seen from the back surface side of the thin-film solar cell. The thin-film solar cell according to any one of claims 1 to 5, characterized in that: 7. The thin-film solar cell according to claim 6, wherein the translucent back surface sealing material is a fluorine-based resin or glass. 8. The method for manufacturing a thin-film solar cell according to claim 1, wherein the light-transmitting opening is formed by processing using a laser beam. To manufacture a thin film solar cell. 9. The light-transmitting opening is formed in a discontinuous line shape by setting a mask on the insulating light-transmitting substrate and processing the light-transmitting opening using a laser beam. Item 10. The method for producing a thin-film solar cell according to Item 8. 10. The light-transmitting opening is formed in a discontinuous line shape by performing ON / OFF control of an oscillator that emits the laser light depending on a processing coordinate position. The method for manufacturing a thin-film solar cell according to claim 8, wherein 11. A light-transmitting opening is formed in a discontinuous line shape by installing a shutter in an optical path of the laser beam and performing opening / closing control of the shutter depending on a processing coordinate position. 9. The method for manufacturing a thin-film solar cell according to claim 8, wherein: 12. The shutter comprises a mechanical shutter, an electro-optical shutter, and an acousto-optical shutter.
A method for manufacturing a thin-film solar cell according to claim 11.