JPS6362913B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a solar cell module, and particularly to a solar cell module in which the connection between each electrode and an external lead wire is improved.

Conventional configuration and its problems Recently, solar cells have been attracting attention as a means of energy supply. The reason for this is that electrical energy can be easily extracted directly from the almost infinite amount of clean solar energy. However, due to the high cost of producing the electrical energy, it has not yet reached the stage where it is fully widespread. However, solar cell modules that utilize the above advantages have begun to appear,
There are signs that it will gradually become popular.

In planning to put solar cells into practical use, it is of course important to reduce the cost of the electricity produced by them, but it is also important to ensure that the usable life of the solar cell modules produced is as long as possible. Must be. That is, the long-term reliability of the product must be high, and for this reason, efforts have been made to improve the reliability and long-term life of solar cell modules, but there are still some points that cannot be said to be sufficient.

For example, several defects have been pointed out in conventional solar cell modules that cause a decrease in reliability, one of which is the lack of strength of the connection part for extracting electricity from the solar cell element to the outside.

Electricity generated by a solar cell element is collected at its positive and negative poles, and conventionally, thin plate-shaped lead wires or stranded wire lead wires were connected directly to each electrode using silver paint. Such a connection part lacks mechanical strength and is problematic in use, which causes a decrease in reliability. As a means to improve the lack of strength of such conventional connections,
A method has been proposed in which each of the positive and negative electrodes is once connected to a glass frit-filled silver electrode, and a thin plate-shaped lead wire or stranded lead wire for an external terminal is soldered to the glass frit-filled silver electrode. In this case, external terminals could be soldered to the glass fritted silver electrode, which improved the strength and reliability of the connection to some extent, and made mechanization possible, but the process of forming the glass fritted silver electrode This not only increases the process cost, but also requires heat fusing treatment at a temperature of at least 400°C, which requires energy to prevent the adverse effects of heat on the solar cell module, making it economically difficult. It is becoming a disadvantage.

OBJECTS OF THE INVENTION The present invention aims to overcome the above-mentioned drawbacks of external terminal connections of solar cell modules. That is, an object of the present invention is to improve the strength of the external terminal connection portion of a solar cell module, and to provide a solar cell module that is not disadvantageous in terms of energy economy during production and is highly reliable.

Structure of the Invention The present invention provides a conductive adhesive layer on a portion of a positive electrode and a negative electrode of a solar cell element, and an insulating adhesive layer is provided around the conductive adhesive layer, and the conductive adhesive layer and the insulating adhesive layer are provided around the conductive adhesive layer. A conductive metal plate is adhered on both layers of the layer, and thus each of the electrodes and the conductive metal plate are electrically connected through the conductive adhesive layer, and also through the insulating adhesive layer. A solar cell module is provided in which the metal plates are firmly joined and lead wires are soldered onto the metal plates.

Generally, the thinner the solar cell element is, the more problems there are in the strength of the connection portion with the external terminal and its manufacture, but the present invention can be easily applied to thin film solar cell elements.

Description of Examples Specific examples will be described below with reference to the drawings.

FIG. 1 is a plan view of a conventional solar cell element.
FIG. 2 is an end sectional view taken along line AA' in FIG. 1 to show the connection at the negative pole according to the present invention.

Regarding the case where a CdS/CdTe based solar cell element is used, in FIG.
A film and a C film are formed in this order, and finally an Ag electrode (positive electrode) 5 is formed. Also CdTe
An Ag--In electrode (minus electrode) 6 is formed on the CdS film 2 on which the film, C film, and Ag electrode 5 are not formed. In conventional solar cell elements, Ag electrode 5
Then, use the Ag-In electrode 6 as it is and take out the external terminal lead wire directly from it by adhering it with Ag paint or the like, or fuse and form the glass fritted Ag electrodes 51 and 61 only in the part where the lead wire is taken out. I used to take out the lead wire from there. This method has the drawbacks mentioned above.

The present invention improves the drawbacks of the conventional method as described above, and will be explained with reference to FIG. FIG. 2 shows the connection of the external terminal lead wire from the negative electrode (Ag-In electrode) of the solar cell element as shown in FIG. 1. A CdS film 2 is formed on the glass substrate 1. The Ag--In electrode 6 is formed thereon. According to the present invention, a conductive adhesive layer 8 is formed by applying a known room-temperature curing Ag paint to the portions of the Ag--In electrode necessary for attaching lead wires for external terminals. Next, an insulating adhesive layer 9 made of a known insulating resin is applied and formed around the conductive adhesive layer 8. Next, a conductive thin metal plate 7 is adhered onto the insulating adhesive layer 9 and the conductive adhesive layer 8. Next, the lead wire 10 is fixed onto the conductive metal thin plate 7 with solder 11. As a result, the external terminal lead wire 10 is electrically connected to the Ag-In electrode 6 through the solder 11, the thin metal plate 7, and the conductive adhesive layer 8, and is also firmly secured by the insulating adhesive layer 9. The conductive metal plate 7 and the Ag-In electrode 6 are bonded to each other.

As the conductive metal thin plate 7, for example, a Cu plate,
A thin plate of Ag plated Cu plate can be used, and an insulating resin adhesive such as epoxy resin or silicone resin can be used as the insulating resin forming the insulating adhesive layer. It will also be clear that the lead wire connections on the positive electrode (Ag electrode) can be similarly formed as described above.

Effects of the Invention In the solar cell module according to the present invention, the external lead wire is electrically connected to the positive and negative electrodes of the solar cell element with a conductive adhesive and a conductive metal thin plate, and at the same time, an insulating adhesive The conductive metal plate and each electrode are firmly joined by the adhesive layer, and the lead wire itself is soldered to the conductive metal plate, which is superior to the conventional structure in which the lead wire is attached directly to each electrode. As a result, damage is reduced, the life of the solar cell module is extended, and reliability is improved. Note that the conductive metal plate of the lead wire may be soldered in advance and bonded to the adhesive layer. Furthermore, when the lead wires are soldered after adhering the conductive metal plates, the accompanying heat is dissipated by the metal plates, and the adverse effects of heat can be reduced.
Furthermore, the external lead wires are generally guided to the outside by passing through holes made in the back protection plate to protect the solar cell element, but if a metal plate with a larger area than this hole is provided, the lead wires can be pulled. The metal plate will not peel off even if it is subjected to such stress, and the effects of external stress can also be prevented.

Although the above description has been made regarding a CdS/CdTe solar cell element, it is clear that the present invention can be similarly applied to an a-Si solar cell element.

In the above specific example, it was explained that the insulating adhesive layer 9 was applied only to a limited area, but in order to provide mechanical protection and moisture resistance, it was applied to the entire surface of the element, leaving only the area necessary for connecting the conductive metal plates. May be applied.

[Brief explanation of drawings]

FIG. 1 is a plan view of a conventional solar cell element.
FIG. 2 is an end sectional view taken along line A-A' in FIG. 1 to show the connection at the negative pole according to the present invention. 1 is a glass substrate, 2 is a CaS film, 51 is an Ag electrode,
6 is an Ag-In electrode, 7 is a conductive metal plate, 8 is a conductive adhesive layer, 9 is an insulating adhesive layer, 10 is a lead wire, and 11 is solder.

Claims (1)

[Claims] 1. A conductive adhesive layer is provided on a part of the positive electrode and the negative electrode of the solar cell element, an insulating adhesive layer is provided around the conductive adhesive layer, and the conductive adhesive layer and the insulating adhesive layer are provided around the conductive adhesive layer. A conductive metal plate is bonded on both layers of the adhesive layer, and thus each electrode and the conductive metal plate are electrically connected through the conductive adhesive layer, and also through the insulating adhesive layer. A solar cell module characterized in that the metal plates are firmly joined together, and lead wires are further soldered onto the metal plates. 2. The solar cell module according to claim 1, wherein the solar cell element is of a thin film type. 3. The solar cell module according to claim 2, wherein the solar cell element is of the CdS/CdTe type.