JPH05136442A - Photovoltaic device - Google Patents

Abstract

PURPOSE:To increase photovoltaic output without an increase in cost by bonding metal wires lower than 1X1O<-6> OMEGAm in resistivity to output parts of first and second electrodes of metallic conductor. CONSTITUTION:Transparent conductor films 2 for first electrodes are arranged at regular intervals on a translucent, insulating glass substrate 1, and amorphous semiconductor films 3 are formed on the conductor films. Conducting metal films 4 for second electrodes are formed on the semiconductor films in such a manner that each film 4 extends in part to the conductor film 2. All these laminated films form photoelectric regions 10. When light is incident to amorphous semiconductor films 3 through the insulating substrate 2 and the transparent conductor films 2, photoelectromotive forces are coupled in series and the resulting voltage appears between output parts 5 and 6. The output parts are bonded with leads of silver or copper wire having a resistivity lower than 1X10<-6> OMEGAm.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photovoltaic device such as a solar cell.

[0002]

2. Description of the Related Art Since a solar cell directly converts sunlight energy into electric energy, it is possible to obtain clean and inexhaustible energy. In recent years, when global environmental issues have been attracting attention, solar cells have attracted more and more attention. ing.

However, even in the solar cell which has received such attention, both the manufacturing cost and the output need to be improved, and in fact, it has not been widely used in general. In particular, regarding the output, when taking an amorphous solar cell as an example, the effective area is as low as 0.8 to 1.0 W in a 10 cm square, and there is an urgent need to improve the output.

In order to improve the output of the solar cell, it is necessary to increase the effective area and the conversion efficiency. In this respect, an integrated structure (for example, JP-A-55-107) is used.
No. 276) and a method of forming an integrated structure by patterning with a laser beam (hereinafter referred to as a laser patterning method) (for example, Japanese Patent Laid-Open No. 62-3347).
Various solar cells aiming to increase the effective area have been proposed, such as Japanese Patent Laid-Open No. 7).

[0005]

However, even in these structures, there are problems as described below, which is not sufficient, and further improvement has been demanded.

That is, both the integrated structure and the laser patterning method are effective in increasing the effective area, but on the other hand, in order to increase the effective area, a current is taken out from the semiconductor layer to be the photoactive layer. There is no choice but to reduce the width of the electrode extraction portion of the electrode. Therefore, the area of the electrode lead-out portion is reduced, and the series resistance of the electrode is increased. As a result, despite the increase in the effective area, the output of the solar cell cannot be improved as expected, and since the resistance value of the electrode extraction portion is large, there are many restrictions when extracting the current. I was receiving it.

The present invention has been made in view of such conventional problems, and an object thereof is to provide a photovoltaic device capable of improving the output without increasing the manufacturing cost.

[0008]

In order to achieve the above object, a photovoltaic device of the present invention is provided with 1 × on a lead-out portion of first and second electrodes formed of a metal film having good conductivity. 10
It is characterized in that a highly conductive metal wire having a resistivity of ^-6 Ωm or less is welded.

[0009]

The metal wire (having a diameter of 0.01 mm to 1) having good conductivity is formed on the electrode lead-out portion which becomes smaller as the effective area increases.
By welding (0 mm) with a laser or the like, the volume of the electrode extraction portion is substantially increased, and the resistance value of this portion is reduced. Further, by continuously welding the metal wires as a part of the laser patterning process, it is possible to suppress an increase in capital investment and the number of processes.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a photovoltaic device according to an embodiment of the present invention, and this photovoltaic device is specifically an amorphous solar cell.

In the figure, 1 is an insulating substrate made of glass having a light-transmitting property, and 2, 2, ... Are transparent conductive films (light-transmitting property) formed on the insulating substrate 1 at regular intervals as first electrodes. It is a conductive film and is made of tin oxide (SnO ₂ ).

Reference numerals 3, 3, ... Denote amorphous semiconductor films formed on the respective transparent conductive films 2 so as to be amorphous silicon (a-S).
i) etc. The amorphous semiconductor film 3 includes a pin junction in which the inside is laminated in the order of p-type, i-type, and n-type from the bottom, and functions as a photoactive layer.

Reference numerals 4, 4, ... Denote metal electrode films as second electrodes formed on the respective amorphous semiconductor films 3 so as to partially overlap the transparent conductive films 2, 2 ,. Has been formed. These metal electrode films 4, 4, ... Are made of a metal having good electrical conductivity having a resistivity of 1 × 10 ⁻⁶ Ωm or less, such as aluminum (Al).

Each of the transparent conductive films 2, 2, ... Or the metal electrode films 4, 4 ,.
., Respectively, and when light is incident on each of the amorphous semiconductor films 3, 3, ... Through the insulating substrate 1 and the transparent conductive films 2, 2 ,. These generated photovoltaic powers are added in series, and both electrode extraction parts 5, 6
Will be taken from.

It should be noted that, on both of these electrode take-out portions 5 and 6,
The metal wires for drawing 7 and 8 having good conductivity, which is a feature of the present invention
Are connected. These lead-out metal wires 7 and 8 are reduced in size with the increase of the effective area.
For substantially increasing the volume of 1 × 10 ^-6 Ω
It is made of silver (Ag), copper (Cu), or the like having a resistivity of m or less, and the diameter thereof is, for example, about 0.1 mm corresponding to the width dimension of the electrode extraction portions 5 and 6.

These two metal wires 7 and 8 are continuously formed as part of the laser patterning process in the manufacturing process of the photovoltaic device described below.

Next, a method of manufacturing the photovoltaic device configured as described above will be described. After depositing a transparent conductive oxide such as SnO ₂ on the entire surface of the glass substrate 1, adjacent gaps are removed by laser beam irradiation to form individual transparent conductive films 2, 2 ,. ..

One of the conductive conductive materials and the insulating member are stripped in parallel from one side of the transparent conductive films 2, 2, ... It is formed. Amorphous semiconductor film 3 such as a-Si is formed on substantially the entire surface of substrate 1 including the surfaces of the conductive material and the insulating member.
Are laminated in the order of p-type, i-type and n-type.

After depositing a metal electrode film such as Al on the entire surface of the substrate 1 including the exposed portions of the amorphous semiconductor film 3 and the transparent conductive film 2 by vapor deposition or the like, the amorphous material positioned on the conductive member is formed. The semiconductor film 3 and the metal electrode film 4 are irradiated with a laser beam to melt the laminated body including the amorphous semiconductor film 3 and the metal electrode film 4, and a melt generated by the melting, that is, a silicide alloy is surrounded by an amorphous material. The transparent conductive film 2 and the metal electrode film 4 are electrically connected to each other by adhering to the conductive member while penetrating the high quality semiconductor film 3.

On the other hand, the laminate on the insulating member is irradiated with a laser beam, the output of this laser beam is controlled, and the laminate consisting of the amorphous semiconductor film 3 and the metal electrode 4 film is removed.
By dividing the amorphous semiconductor film 3 and the metal electrode film 4 and separately forming the individual amorphous semiconductor films 3, 3, ..., Metal electrode films 4, 4 ,. Complete the photovoltaic device.

After the photovoltaic device is completed, the electrode lead-out parts 5, 6
After the metal wires 7 and 8 of Ag or the like are set on them, they are welded by the laser L, respectively.

With respect to the solar cell (invention product) constructed as described above, the results of the photovoltaic characteristic test conducted in comparison with the solar cell without the metal wires 7 and 8 (conventional product) are shown in Table 1 and FIG. 2 shows. In FIG. 2, the horizontal axis represents the output voltage,
The vertical axis represents the output current. The effective area of the test piece is 117.8 × for both the invention product and the conventional product.
A 124.5 mm square substrate was used.

[0023]

[Table 1]

From this test result, it was found that the product of the present invention has a larger output of about 5% than the conventional product, even though the effective area is the same.

The present invention is not limited to the above-described embodiments, but can be applied to photovoltaic devices having various structures. For example, a device patterned by chemical etching or the like or an integrated device can be used. Of course, it is also applicable.

[0026]

As described above in detail, according to the present invention, the electrode lead-out portion is formed by welding the metal wire having good conductivity onto the electrode lead-out portion which becomes smaller as the effective area increases. It becomes thicker and the volume substantially increases, and the resistance value of this portion can be suppressed lower than that of the conventional structure.
As a result, when the effective area is increased, the cell output can be improved by the increase in the area, and a photovoltaic device with high output can be obtained.

Further, since the resistance of the electrode lead-out portion is lowered, there is an advantage that the design for taking out the electric current can be freely performed.

Further, since the metal wire can be welded continuously as a part of the laser patterning process, it is possible to suppress the capital investment and increase in the number of processes, and to improve the output without increasing the manufacturing cost. It is possible.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing the structure of a photovoltaic device according to an embodiment of the present invention.

FIG. 2 is a voltage-current curve diagram showing the output characteristics of the photovoltaic device in comparison with the output characteristics of a conventional photovoltaic device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Glass substrate 2 Transparent conductive film (first electrode) 3 Amorphous semiconductor film 4 Metal electrode film (second electrode) 5 Electrode extraction part of first electrode (+ pole) 6 Electrode extraction part of second electrode (-pole) ) 7,8 Metal wire for extraction 10 Photoelectric conversion region L laser

Claims (1)

[Claims] 1. A photovoltaic device comprising a substrate, a first electrode, a semiconductor layer having at least one photoactive layer, and a second electrode, wherein the photovoltaic device is configured to extract an electric current from these two electrodes. 1 × 1 on the electrode extraction part of both electrodes
A photovoltaic device, characterized in that a highly conductive metal wire having a resistivity of 0 ^-6 Ωm or less is welded.