JPH02271681A - Solar cell device - Google Patents

Abstract

PURPOSE:To obtain a light transmission type solar cell device transmissible through fine pores and to provide a satisfactory external appearance without remarkably observed linear light shield and a light transmission unit by providing fine pores reaching a transparent electrode through an amorphous semiconductor layer from rear face electrodes at the whole surface. CONSTITUTION:Fine pores 7 passing rear electrodes 41-43 and an amorphous semiconductor layer 33 are dispersed at the whole surface, and fine grooves 6 for dividing the electrodes of unit cells 10, 20 are formed by nonlinearly and irregularly coupling the pores 7. Since the solar cell device passes a light via the through holes, it can be transmissible. However, it does not have a remarkably observed linear part. Thus, it is transmissible, and does not have the remarkably observed linear light transmission part.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides a transparent solar cell device in which unit cells of a solar cell using a thin film semiconductor mainly composed of amorphous silicon or the like are connected in series. Regarding.

[Conventional technology]

Amorphous semiconductor thin films formed by glow discharge decomposition of raw material gas or photo-CVD can be easily grown into large areas because they are obtained by vapor phase growth, and are expected to be used as materials for low-cost solar cells.

In order to efficiently extract electric power generated from such an amorphous solar cell, it is well known to construct a solar cell device in which unit cells are connected in series. In this structure shown in FIG. 2, transparent electrodes 21, 22, 23, etc. made of a transparent conductive material such as 1To or 5nO1 are formed in a rectangular pattern on a transparent insulating substrate 1 such as a glass substrate. , on which a pattern of amorphous semiconductor layers 31, 32, 33, etc., which are photovoltaic force generating parts,
Next, the back surface made of metal thin film 'ti41,42.43・
Stack the patterns in order. Then, the pattern of the picture electrode and the amorphous semiconductor layer is formed such that, for example, the transparent electrode 22 of one unit cell has a part 5 in contact with the back electrode 41 of the adjacent unit cell,
Each unit cell is connected in series by a connection 5. The back electrode is divided by grooves 6. Various patterning process techniques such as photoetching, laser scribing, and mechanical scribing are used to form patterns for each layer of this series-connected solar cell.

In recent years, amorphous solar cells have been used or are being considered for use in various general consumer applications, but one of them is that solar cells do not completely block light but allow some light to pass through. In other words, light-transmissive solar cells that allow the opposite side to be seen through the solar cell are attracting attention as suitable for building materials and automobile sunroofs.

The structure of such a light-transmissive solar cell can be roughly divided into two types. One method uses a transparent conductive film instead of a metal thin film as the back electrode, and makes the amorphous semiconductor layer relatively thin to allow part of the incident light to pass through the back surface. Another method is to use amorphous silicon layers 31, 32, 33,
...and a large number of minute holes penetrating the back electrodes 41, 42, 43, and a portion of the incident light is transmitted through these minute holes. These tiny pores are usually formed in a similar way. That is, after forming the back electrode layer, when forming a pattern of the back electrode divided into normal unit cells by a photoetching process,
At the same time, a large number of micro holes are formed in the back electrode.Next, using this back electrode as a mask, the amorphous semiconductor layer is etched, for example, by plasma etching. A pattern of microscopic holes in the layer is formed, forming through-holes that reach the transparent electrode and allow light to pass through. At this time,
The portion of the amorphous semiconductor layer corresponding to the pattern that separates adjacent unit cells of the back electrode will also be removed by etching, but this portion will separate the edges of the amorphous semi-semiconductor m of each unit cell. Since this is just a change in power, there is almost no problem electrically.

[Problem to be solved by the invention]

Of the two conventional techniques related to the structure of a light-transmissive solar cell, the former method of using a transparent conductive film for the back electrode has the following problems. In other words, part of the incident light is mainly absorbed by the amorphous semiconductor layer, and the rest is transmitted to the back surface. However, since the amorphous semiconductor layer has a higher absorption rate for short wavelength light than for long wavelength light, Light inevitably contains many long wavelength components, giving it a strong red color. Therefore, since the transmitted light has a color significantly different from that of natural light, the applications of the light are greatly limited.

On the other hand, the latter method, in which many tiny holes are made in the amorphous semiconductor layer and the back electrode, does not have this problem because the light reaches the front side without passing through the amorphous semiconductor layer. In this case, as shown in FIG. 3, in addition to a large number of minute through-holes 7 in the back electrode and the amorphous semiconductor layer, there are linear grooves 6 that divide the unit cells 10 and 20. This groove also allows light to pass through it, but it stands out because it is sandwiched between linear light-opaque parts on both sides, making it a light-transmissive type solar cell device where appearance is important even if there is no electrical problem. undesirable as such.

An object of the present invention is to provide a solar cell device that can be seen through a hole penetrating an amorphous semiconductor layer and a back electrode, and does not have a linear light-transmitting part that stands out.

[Means to solve the problem]

To achieve the above object, the present invention provides a solar cell unit cell consisting of a transparent electrode, an amorphous semiconductor layer, and a back electrode stacked on a transparent insulating substrate, in which an extension of the back electrode of one cell is adjacent to the solar cell unit cell. In a solar cell device that is connected in series by contacting the transparent electrode of the cell, a large number of micropores are formed on the entire surface that penetrate the back electrode and the amorphous semiconductor layer and reach the transparent electrode, and the space between the unit cells of the back electrode is The holes are electrically isolated by a narrow groove formed by non-linearly and irregularly connecting the holes.

[Effect]

In the above solar cell device, the light-transmitting back cover and the through-holes in the amorphous semiconductor layer are present on the entire surface, and some of them are connected non-linearly and irregularly, making them clearly recognizable as straight lines. Since there is no light transmitting part, it looks uniform in appearance.

〔Example〕

FIG. 1 shows the boundary between unit cells in a solar cell device according to an embodiment of the present invention. Microholes 7 penetrating the back electrode and the amorphous semiconductor layer are distributed over the entire surface.
The narrow grooves 6 that divide the back electrodes of the unit cells 10 and 20 are formed by connecting minute through holes 7 non-linearly and irregularly.

This solar cell device can be seen through because light passes through the through hole. However, there are no straight lines that stand out.

Figure 4 (al, (a'), (bl, (b'), (cl,
(c') shows the manufacturing process of Konoyouna solar cell, (b), fc) is a plan view, (a'),
(b") and (c') are cross-sectional views corresponding to each. First, a SnO* film was formed on the glass substrate 1 to a thickness of 3,000 mm, and was patterned using a laser scribing method to make it transparent. It is divided into electrodes 21, 22, 23, .

Next, an amorphous semiconductor layer with a PLN structure is formed to a thickness of 4000 nm, and similarly patterned using the laser scribing method to form semiconductor layer regions 31, 32, 3 of each unit cell.
Divide into 3... A metal layer 40 made of a K13 film is formed thereon to a thickness of 3000 nm by sputtering.

This state is ta++(a') in FIG.

In the next step, exposure, development, and etching are performed using a normal photoetching process to form the metal layer 40 with a radius of 0.
Two circular holes 70 are formed so that the distance between the centers of the circles is 0.6. A part of this circular hole 70 existing at the boundary of the unit cell is connected non-linearly and irregularly by the narrow groove 6, and the back electrodes 41, 42.4 of the adjacent unit cell are connected non-linearly and irregularly.
A groove 6 is formed to electrically separate the 3... This state is shown in FIGS. 4(b) and 4(b').

After this, a back electrode 4142 with a small circular hole 70,
43 as a mask, the transparent electrodes 21, 22, 23 are connected to the micro circular holes 70 by a normal plasma etching method, penetrate the amorphous semiconductor layers 31, 32, 33, and
Form a micropore 7 that reaches . At this time, the back electrode separation groove 6
Although the amorphous semiconductor layer below is also removed, there is no electrical problem. This state is shown in FIGS. 4(cl) and (c').

[Effects of the Invention] According to the present invention, light that can be seen through the microholes is provided throughout the entire surface from the back electrode on the opposite side of the light-transmitting insulating substrate, penetrating the amorphous semiconductor layer and reaching the transparent Ti. A transmission type solar cell device can be obtained, and since the separation groove of the back electrode between the unit cells is formed by connecting the micropores non-linearly and irregularly, there is no noticeable straight light-shielding part or transparent part. It has a good appearance because it does not have a light part.

Furthermore, this solar cell can be simply manufactured by simply changing the mask during back electrode patterning and etching down to the amorphous semiconductor layer, so there is no increase in the number of manufacturing steps.

[Brief explanation of drawings]

FIG. 1 is a plan view of the main parts of a solar cell device according to an embodiment of the present invention, FIG. 2 is a sectional view of a conventional solar cell device, and FIG. 3 is a plan view of main parts of a conventional light-transmissive solar cell device. , Figure 4(a),
(a'), (bl, (b'), tel, and (c') represent manufacturing steps of a solar cell device according to an embodiment of the present invention;
Mountain 1. (C) is a plan view, (a'), (b''), (C''
) is a cross-sectional view. 1 Ni glass substrate, 21, 22, 23: i3 bright electrode,
31.32° 33: amorphous semiconductor layer, 40: metal layer, 41.4243: back electrode, 5: connection section, 6: dividing groove, 7: minute through hole, 10, 20: unit cell. -'-"4, Agent Hirishi Iwao Yamaguchi, =. Uni., To ZJ No. 16 Army 1 7 hours sunk 1 C Penetration Ram C 'I13 Figure 2' 3121 3222 33231i44 Procedure Amendment (self-motivated) 1. Display of the incident λ Name of the invention 1999 Patent application No. 93883 Solar cell device

Claims (1)

[Claims] 1) Solar cell unit cells consisting of a transparent electrode, an amorphous semiconductor layer, and a back electrode stacked on a transparent insulating substrate are connected in series by an extension of the back electrode of one cell coming into contact with the transparent electrode of an adjacent cell. In this case, a large number of micropores are formed on the entire surface that penetrate the back electrode and the amorphous semiconductor layer and reach the transparent electrode, and the unit cells of the back electrode are formed by connecting the micropores nonlinearly and irregularly. A solar cell device characterized in that the solar cell device is electrically separated by a narrow groove.