JPS58155770A - Substrate for amorphous silicon solar cell - Google Patents

Abstract

PURPOSE:To obtain the amorphous Si solar cell applicable to various power simply by forming a plurality of beltlike conductive layers to the other end from one end of an insulating substrate and overlapping a conductive layer consisting of different quality of material extending over the whole longitudinal region except one part of the width of a belt. CONSTITUTION:A transparent electrode 10 is evaporated onto a glass plate 9 ane etched selectively, electrode layers 10' are formed at regular intervals, and Al 11 is evaporated selectively to the one parts. When amorphous Si thin-films 12 are deposited in order of a pin type, Al 11 diffuses among the thin-films and reaches up to the surfaces of the thin-films 12, and diffusion layers 13 are formed. Al layers 14 are formed adjacent to the layers 13, and sections among elements are connected in series, and used as the back electrodes of adjacent elements at the same time. Electrode leads 15, 16 are fitted to elements at both ends. According to said constitution, outputs can be varied freely without changing a mask, and the solar cell, a utilization rate of the substrate therein is high, is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an amorphous silicon solar cell substrate, and provides a solar cell substrate that can easily form solar cells compatible with various power consumptions.

Conventionally, thin film solar cells in which a photoelectric conversion thin film is deposited on a single substrate are connected in series on the substrate, as typified by solar cells made of amorphous silicon (hereinafter abbreviated as A-8I). FIGS. 1a and 1b show series-connected solar cells that have been proposed in the past. Figure 1 a, b
, 1 is an insulating substrate, 2 is a light-receiving side electrode, and 3 is a-8
i thin film, 4 is the back side electrode. When any of these devices is completed as a device, the conductive film on the insulating substrate does not exist continuously to the edge of the substrate, but has an island shape. On the other hand, advances in semiconductor circuits have continued to reduce their power consumption, but conventional technology had the disadvantage of having to prepare a new mask each time a solar cell with a different power consumption was created. .

The present invention has a function of connecting a plurality of A-8I thin films in series on the same substrate as in the conventional example, and has high substrate usage efficiency that allows the output power to be freely changed without changing the mask. 8i solar cell substrate.

The technology underlying the present invention will be described below. Second
Figures a-c show the process of penetrating and embedding metal in the a-8i thin film. First, electrodes 6 i and 62 made of Al are deposited on a part of the washed glass substrate 5 (FIG. 2a). Next, the a-8i thin film 7 was coated with AI1.

The electrodes 61 and 62 are deposited so that electrode terminals can be taken out (FIG. 2b). Deposition conditions are substrate temperature 180”C~3
00'C vacuum degree was used in the range of 0.2 to 2 Torr.

A previously deposited by depositing an a-8i thin film 7
r1. Electrodes 61 and 62 diffuse through the a-8i thin film 7 and reach its surface. It is desirable that the film thickness of the A2 electrode 6 it 62 be approximately the same as that of the a-8i thin film 7 or slightly thicker.

Next, electrodes 81 and 82 made of Au are deposited on the a-8i thin film T, and this Aμ electrode 81 and A! a-8 with electrode 61
i Sandwich the thin film 7 (FIG. 2C).

In Fig. 2C, the resistance between the AI1 electrode 61, the A2 electrode 81, and the AI electrode 61 was measured.
A specific resistance of Crn or less was obtained. Usually obtained a-
Considering that the specific resistance of 8iO is about 109Ωm,
Ar1. It can be seen that a sufficiently low resistivity can be obtained by metal diffusion in the electrode 61. The size of the electrodes for series connection is determined by the width o
, saI, length 10 crn%, thickness 5000 A, the actual resistance is less than 10 Ω·, and the resistance loss is extremely small, less than 1 mV when a current of 1 A flows.

Next, a substrate according to an embodiment of the present invention using this technology and an a-8i solar cell using the same will be described.

This applies to the case where a plurality of photovoltaic elements are connected in series on the same glass substrate. FIGS. 3a to 3d are diagrams illustrating a procedure for manufacturing a photovoltaic device according to an embodiment of the present invention. A transparent electrode 10 is deposited on almost the entire surface of the glass substrate 9 (FIG. 3a). Electrode layers 10 are formed by etching the transparent electrodes 1o in an appropriate pattern and disposing them in parallel at a constant interval.
After forming ', a metal layer 11 called Aρ is deposited on a part thereof. Note that an A4 metal layer may be deposited on the entire surface and then formed into a suitable pattern by etching (FIG. 3b). Using this as a substrate, a-8i thin films 12 are deposited, for example, in the order of p-type, i-type, and n-type (FIG. 3C). Note that in order to simplify the drawing, they are shown as one unit in the figure. As described above, during the deposition of the A-8T thin film 12, the previously deposited AM metal layer 11 diffuses and reaches the surface of the A-8I thin film 12. 13 reaches the surface of the a-8i thin film 12. 13 reaches the surface of the a-8i thin film 12. 13 is a region where the A°C metal layer 11 is diffused into the A-8T thin film 12 and has a low resistance. As shown in FIG. metal layer 1
4 is deposited. This A! The metal layer 14 serves as a series connection between elements and also serves as a back electrode of an adjacent element. Electrode leads 16, 16 are attached to the elements at both ends to form series connected elements.

Through the above steps, a
-8i solar cells are obtained. That is, this thin film solar cell includes a photoelectric conversion thin film layer made of the a-8i thin film 12, a transparent electrode layer 10' arranged in parallel on one principal surface of the photoelectric conversion thin film layer at a constant interval, and the above-mentioned A2 electrode layer 14 arranged opposite to the transparent electrode layer 10' is provided on the substrate 9 on the other main surface side of the photoelectric conversion thin film layer, and the transparent electrode layer 1σ and the AIt electrode layer 14 are used for the photoelectric conversion. Electrical connection is made through a conductive layer formed by diffusion into a membrane layer.

In the a-8i solar cell of the embodiment described above, A1 is used as the conductive layer connecting the opposing electrodes, but the conductive layer 11 formed on the transparent electrode 10' is the a-8i conductive film 1.
Any example may be used as long as it diffuses during the deposition of step 2, reaches the surface, and has a low resistance. For example, in addition to 82, Au,
Metal layers such as In + P4 + Pt can be used.

When the substrate according to the present invention (FIG. 3b) is used, the plan view of the completed solar cell will be as shown in FIG. 4a. A-8i is deposited on the entire surface of the substrate 9 in FIG. Note that FIG. 4a is a view from the opposite side of the substrate according to the present invention;
The figure is a cross-sectional view. As you can see from the diagram, a-8
The solar cells are connected in a two-element array. In order to obtain a current commensurate with the power consumption of the device to be mounted, cut the solar cell to an appropriate size in the horizontal direction of Figure 4a. After cutting, the cut ends are likely to short-circuit, so the material for the electrode 14 may be masked with a metal wire or the like along the cut line during vapor deposition to separate the electrodes 34, or the cut ends may be covered with a suitable protective material. It's better to cover it.

Even in the conventional example having the structure shown in Fig. 1, in this case, as shown in the present invention, there is no conductive film between one end of the insulating substrate and the other end, and moreover, as shown in the present invention, the electric power can be freely selected. Even in this case, if the substrate according to the present invention is used, a solar cell can be easily manufactured in accordance with the power consumption. As mentioned above, the fundamental difference between the present invention and the conventional example shown in Fig. 1 is whether the conductive film is present up to the edge of the insulating substrate. As a case in point, even if a-8i such as stainless steel is deposited on an opaque insulating substrate such as ceramics, it does not dissipate significantly into the a-8i film, for example, S n 0
2 r I TO+ T i+ N i# Cr *
It is also possible to evaporate or apply a plurality of substances such as N, I, Cr, W, etc. in the form of strips, but in this case, since it is impossible to enter light from the substrate side, the electrodes that connect each element in series are installed at the end. should be used.

As described above, the thin film solar cell using the substrate according to the present invention has almost the same characteristics as individual single solar cells connected in series outside the amorphous layer deposition area, and since the thin film can be deposited over the entire substrate, the mask The likelihood of characteristic deterioration due to pinholes, etc., which are likely to occur near the opening, is also reduced. Furthermore, when attempting to separate the A-8I thin film as in the conventional example, the deposition vacuum level is approximately I Torr, so the thin film sag due to the mask is large, and the space required for separation becomes large. Since the above-mentioned metal films are deposited in a high vacuum, the space required for separation is reduced. Therefore, the utilization efficiency of the substrate is greatly improved. Furthermore, advances in semiconductor integrated circuit technology have made it possible to easily manufacture solar cells of different sizes to accommodate various power consumptions.

[Brief explanation of the drawing]

Figures 1a and 1b are partially cutaway perspective views of thin film solar cells using conventional substrates, and Figures 2a to 2c illustrate the principles used to effectively utilize the substrate of the present invention. FIGS. 3a to 3d are perspective views of the electric device of FIG. 4A and 4B are a completed plan view and a sectional view of a thin film solar cell using a substrate according to an embodiment of the present invention. 6.9...Φ glass substrate, 6,81,11...-working...
・Metal layer, 7, 12...a-8t thin film, 10'
...Transparent electrode, 14... Back electrode. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 412 Figure 3 Figure n

Claims (1)

[Claims] A plurality of strip-shaped conductive layers continuous from one end to the other on an insulating substrate, and a conductive layer that overlaps with the conductive layer except for a part in the width direction of the conductive layer and is made of a different material from the conductive layer. An amorphous silicon solar cell substrate characterized in that a conductive layer is provided over the entire length direction.