JPS61202477A - Thin film photovoltaic element - Google Patents

Abstract

PURPOSE:To increase the generating area efficiency by forming an insulating layer after opening pores at a metal substrate, and removing electrodes from the back surface through a conductive layer formed at the inner surfaces of the pores and to the extension to the back surface, thereby reducing the electrodes. CONSTITUTION:Pores 2 are opened by pressing at the positions corresponding to the electrodes of a metal substrate 1 made of aluminum. The pores 2 do not increase by simultaneously opening when forming the substrate in the prescribed size by pressing from an aluminum plate. The substrate 1 opened with the pores 2 is subjected to an anodic oxidation to form an oxide film 3 on the entire surface of the substrate 1 and the inner surfaces of the pores 2 to provided an insulation. Lower electrodes 4 are formed by depositing method near the pores 2. In this case, the depositing metal is bonded from the interior of the pores 2 to the back surface to form the back surface exposing electrode 5.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a thin film photovoltaic element, particularly to a structure of a through hole for taking out an electrode of a metal substrate in which the element is provided on an insulating layer made of an oxide film.

BACKGROUND OF THE INVENTION Conventionally, a thin film photovoltaic device using a metal substrate of this type has a structure as shown in FIG.

In the figure, A is a plan view and a sectional view taken along line B-B of B1-1tA. That is, a metal substrate 1 such as aluminum
An oxide film 3 is formed thereon using an anodic oxidation method.

On top of this, a metal mask is used to selectively form a lower electrode 4, which is to become one electrode of the photovoltaic element, by vapor deposition.

Next, a thin film semiconductor layer having a photoelectric conversion function, for example, an amorphous silicon layer 6, is selectively formed using a metal mask using a plasma CVD method.

Next, the transparent electrode 7 that should become the other electrode of the photovoltaic element
were selectively formed using a metal mask to form a photovoltaic element.

In FIG. 10, areas 1.2 and 3.4 show individual photovoltaic elements formed by the above method on the same metal substrate. Each of these areas is called a cell. Each cell generates a photovoltaic force of 0.6-0.8v in indoor and outdoor light. Normal electronic devices such as calculators are 1.5 to 3. Since a voltage of about 0V is required, about 4 or 3 cells are connected in series. FIG. 10 shows four cells connected in series.

To connect each cell in series, the lower electrode 4, which is one electrode in area 1, and the transparent electrode 7, which is the other electrode in area 2, are connected on the same side of the cell using a metal mask during electrode formation. Selectively overlap. This is 2-3
The same applies to 3-4. This part is called the series connection part 6. And the supply of power to electronic devices is
It was taken out from the terminals (11 and 12) at both ends by soldering lead wires or other means. This part is called the terminal part.

Problems to be Solved by the Invention In such a conventional configuration, the terminal portions θ1, 12) and the series connection portion 6 do not contribute to photoelectric conversion, so in order to improve the area efficiency for power generation, it is necessary to It is important to make the sizes of the two parts as small as possible. Therefore, in practice, the size of the terminal portion (*1.12) is determined so as to facilitate the connection of lead wires for extracting power.

On the other hand, the area of the series connection part 6 allows the flowing current to range from several μ to several meters.
Since A is small, the number may be smaller than that of the terminal portions (11, 12).

Due to the size of the terminal portions (11, 12) required for this connection, there was a problem in that the power generation area efficiency on one device was reduced.

In addition, in this structure where the photoelectric conversion part and the electrode part are on the same side, it is necessary to consider the power extraction from lead wires etc. on the light receiving surface side, and due to the thickness of the lead wires to be connected, it is necessary to When using this thin film electromotive force element in a product, there was a problem in that it caused problems.

Means for Solving the Problems The present invention solves these problems by providing small holes in the electrode portions θ1, 12) of the substrate, securing the area necessary for connecting the lead wires on the back surface of the substrate, The electrode part itself is made smaller. If power is extracted from the back side of the photoelectric conversion surface in this way, the thickness of the lead wire connection part and the lead wire itself when incorporated into an electronic device can be made in the same space as the thickness required by other electronic components of the chassis. In fact, the thickness of electronic devices can be reduced.

In addition, simply making a small hole in the electrode part will cause the electrode parts 11 at both ends of the substrate to be damaged. 12) is short-circuited, it is advisable to cover at least the inner surface of the small hole with an oxide film by anodic oxidation of the substrate to ensure insulation. Preferably, when forming the lower electrode 4 and the transparent electrode 7, vapor deposition is also performed in the hole at the same time, so that conductivity can be measured from the electrode part on the surface to the inner surface of the small hole by the wraparound of the vapor deposition. It can also be formed on the back side through materials.

Function: In this configuration, electric power from the electrode section on the same plane as the photoelectric conversion section can be obtained from the back side through the vapor-deposited conductive material on the inner surface of the small hole formed on the electrode section. The area of the electrode section is limited by the area required to make the small hole, which can be significantly reduced compared to the area required to connect the lead wire. Note that the conductive layer area necessary for connecting the lead wires can be secured on the back surface of the substrate. Furthermore, since there is no extra protrusion on the photoelectric conversion surface that occurs when connecting lead wires, it is advantageous in designing thin products when designing electronic devices.

Example Examples will be described below.

FIG. 1 shows a metal substrate 1 made of aluminum.

In FIG. 2, small holes 2 are formed by pressing or the like at locations corresponding to the electrode portions (11, 12) in FIG. 10, which shows a conventional example described later. The number of man-hours will not increase if the small holes 2 are provided at the same time when the metal substrate 1 is produced to a predetermined size by pressing, for example, an aluminum plate.

4 is a diagram showing the metal substrate 1 provided with the AVi small holes 2 shown in FIG. 3 subjected to anodizing treatment to form an oxide film 3. FIG.

By this treatment, the surface of the metal substrate 1 and the inner surface of the small hole 2 are kept completely insulated. , B shows an enlarged cross-sectional view of the vicinity of the small hole 2. In A and B of FIG. 4, the lower electrode 4, which is to become one electrode, is formed by a vapor deposition method or the like. When forming the lower electrode 4, the vapor-deposited metal also wraps around and adheres to the inside of the small hole 2, and a portion reaches the back surface to form the back exposed electrode portion 5.

B is an enlarged sectional view of the vicinity of the small hole 2. Furthermore, this small hole 2
The area around corresponds to the electrode portion (11°12) of the conventional example shown in FIG.

In the example shown in FIG. 4, the area may be enough to cover the inner surface of the small hole 2 and its extension to the back surface.

In FIG. 5, as in the conventional example, an amorphous silicon layer 6 and a transparent electrode 7 are sequentially formed on this substrate to form a photovoltaic element.

FIG. 6 is a view of the device of FIG. 6 from the back side. A back exposed electrode portion 6 is formed around the small hole 20.

FIG. 7 is a diagram in which what is called a heat seal terminal 8 is connected to FIG. 6 for electrical and physical connection by thermocompression bonding. The right side of the figure is a view before the heat seal terminal 8 is attached, and the left side is a view after the heat seal terminal 8 is electrically brought into contact with the back exposed electrode portion 6. Since there is no extra structure on the back side, a sufficient bonding area can be obtained compared to the front side.

FIG. 8 is a diagram of FIG. 6 with lead wire terminals 9 added.

In this case, since the small hole 2 is provided, a sufficient connection can be obtained by simply inserting and fixing the lead wire into the small hole 2.

FIG. 9 is a diagram in which a metal terminal 10 with a protrusion (not shown) is added to a part of FIG. 6. Since the protrusion is structured to fit into the small hole 2, a reliable connection can be expected.

Effects of the Invention As described above, according to the present invention, a small hole is formed in a metal substrate, an insulating layer is formed after that, and an electrode is connected from the back surface through the conductive layer formed on the inner surface of the hole and the extension portion to the back surface. Therefore, the size of the electrode portion can be reduced and the effective area efficiency for power generation can be increased. Furthermore, if the lead wires are taken out on the back side of the board, it can be applied to thin electronic devices, which is highly effective industrially.

[Brief explanation of the drawing]

Figure 1 is a top view of the metal substrate, Figure 2 is a diagram with a small hole made in the metal substrate, Figure 3A is a diagram of the metal substrate anodized to form an oxide film 3, and B is a diagram of the area near the small hole. FIG. 4A is an enlarged cross-sectional view of a metal substrate on which an oxide film is formed with a lower electrode, B is an enlarged cross-sectional view of the vicinity of the small hole, and FIG. 5 is an amorphous silicon layer on a metal substrate, A diagram showing a transparent electrode formed, Figure 6 is a diagram of the element in Figure 6 viewed from the back side,
Fig. 7 shows a heat-sealed terminal formed on the board shown in Fig. 5 by thermocompression bonding, Fig. 8 shows a lead wire connected to the board shown in Fig. 6, and Fig. 9 shows a metal terminal attached to the board shown in Fig. 6. FIG. 10A is a diagram showing a conventional thin film photovoltaic device;
B is a cross-sectional view of A taken along line B-B'. 1...Metal substrate, 2...Small hole (through hole)
, 3... Oxide film, 4... Lower electrode,
6...Back surface exposed electrode part, 8...Heat seal terminal, 9...Lead wire terminal, 10...
...Metal terminal, 11...Terminal part, 12...
...Terminal section. Name of agent: Patent attorney Toshio Nakao and one other person1i
Figure 1/-1-Al S Niu Act 4 ■Tile Figure 2 2-11 No. 1X Figure 3
1 = 7ILl: Kumu Makousu 2 =
+j\enter 5-utti g Fig. 4 s-ymxttrt, m↑p 3---A M! ! 1 7-°-9Ill Densaki layer δ--Heat Sea 9 Slope 8 Figure 9fσ-bone 4 note Figure 10

Claims (1)

[Claims] A through hole is formed in a part of a metal substrate having an oxide film formed on the surface as an insulating layer, and an insulating layer is formed on the inner surface of the through hole by anodizing, and the insulating layer on the surface of the substrate and the insulating layer on the inner surface of the through hole are formed. and a thin film photovoltaic device provided with a conductive layer spanning the periphery of the through hole on the back side of the substrate.