JP2733853B2 - Manufacturing method of foil electrode type film capacitor - Google Patents

Description

The present invention relates to a method for manufacturing a foil electrode type film capacitor.

[Conventional technology]

In the production of a foil electrode type film capacitor, the base end of the lead wire is crushed and welded to the electrode metal foils located above and below the dielectric film, and then the electrode metal foil and the film are overlapped, and the lead wire is connected. By winding and winding up, a capacitor element from which a lead wire is drawn out is formed. During winding, burrs on the lead wire or irregularities on the top surface of the wire damage the dielectric film at the portion in contact with the lead wire, which often causes an accident that results in poor withstand voltage. Conventionally, in order to prevent this accident, measures have been taken to cover the welded portion of the lead wire with a film sheet and to prevent burrs and irregularities of the lead wire from damaging the dielectric film directly superimposed. FIG. 2 is a sectional view showing a state before winding. Aluminum foils 1A and 2A are disposed on dielectric films 1 and 2, respectively, as electrode metal foils. The aluminum foils 1A and 2A are welded at the base ends of the lead wires 3 and 4, respectively, and are inserted over the welds so as to cover the film sheets 5 and 6, respectively. In this state, film winding is performed.

[Problems to be solved by the invention]

By the way, in the manufacturing method of the foil electrode type film capacitor, the step of welding the lead wire base end to the electrode metal foil,
Extremely difficult to control. Accidents due to the shape due to burrs of the lead wires as welding members mentioned above are also part 1
This could be solved by inserting a film sheet. However, in the welding work, in order to improve the adhesion of the lead wire, if the welding is strengthened, the metal foil is often damaged, and the stress due to the thermoforming in the subsequent process after winding up,
In some cases, the metal foil is cut in the transverse direction at the welded portion to be cut off. As a result, the capacitance becomes significantly lower than the standard value electrically.

During the manufacturing process of the capacitor, if the metal foil is completely cut, it can be detected as a capacitance defect, but the product is shipped, and in use, the stress of the metal foil progresses,
When the metal foil is broken and the long metal foil is cut off at this portion, the capacitance suddenly decreases, leading to a malfunction of the circuit. In order to prevent such a failure during use, the manufacturer performs debugging by applying stress such as a temperature cycle after the completion of the production. However, a good effect cannot be obtained in preventing the above-mentioned sudden decrease in capacitance.

In view of the above circumstances, an object of the present invention is to provide a manufacturing method capable of eliminating the occurrence of an accident due to lead wire welding, obtaining a high yield, and obtaining a highly reliable foil electrode type film capacitor. .

[Means for solving the problem]

The manufacturing method of the foil electrode type film capacitor of the present invention,
After the base end of the lead wire is welded to the electrode metal foil to be wound together with the dielectric film before the winding process, a laminated member made of a metal foil / organic film is covered with the metal foil so as to cover the lead wire. The side is inserted in contact with the lead wire, and is wound up together with the dielectric film.

[Action]

Although described in detail in Examples, the laminated member is two layers, the metal foil side is in contact with the lead wire, and the organic film is interposed between the dielectric film and the lead wire in a wound state, It provides exactly the same protective action as the conventional film sheet, and prevents damage to the dielectric film that occurs during winding. In addition, since the metal foil of the laminated member is in direct contact with the lead wire, it is also in close contact with the electrode metal foil on both sides near the lead wire during winding. Therefore, even if the electrode metal foil is broken, the broken electrode metal foil is electrically connected by the metal foil of the laminated member, and the capacitance does not decrease.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1A is a cross-sectional view illustrating a method of an example for one dielectric film. The aluminum foil 1A is located on the dielectric film 1 and the aluminum foil 1A
The lead wire 3 is welded, and the laminated member 10 composed of the aluminum foil 10A and the polyester film 10B is arranged so as to completely cover the lead wire 3. As shown in FIG. The length films are stacked and wound up.
In addition, as the laminated member 10, the aluminum foil 10A is, for example, 4 to 1
The polyester film 10B having a thickness of 5 μm and a thickness of 4 to 15 μm is used, but the thickness need not be strict. Since the lead wire 3 is welded in the short direction of the long film, the laminated member 10 is also dimensioned and arranged so as to cover the lead wire 3 accordingly. FIG. 1 (b) is an enlarged cross-sectional view of a main part schematically showing a case where the electrode metal foil is broken.
The break usually occurs at the edge of the lead wire 3. Therefore, the aluminum foil 1A, which is the electrode metal foil, is divided in the lateral direction. However, as shown in FIG.
10A is in contact with the lead wire 3 as well as the two separated aluminum foils 1A, so that the electrical connection is maintained,
The entire surface of the aluminum foil 1A is effective as a capacitor electrode,
Small decrease in capacitance.

The product manufactured by the present embodiment and the product of the conventional process are
In terms of the defective rate of capacitance during the manufacturing process, a remarkable improvement was observed at 0.8% from 2% of the conventional product. Furthermore, when 0.8% of defective products were examined, it was found that the capacitance value was 20% or less of the nominal value, and was zero. That is, this defective product does not include any defect due to lead wire welding, and the effectiveness of the laminated member has been proved. In addition, temperature cycle (−40 ゜ ~
After 100 cycles of a cycle of changing the temperature to + 105 ° C.), three out of 5,000 conventional products had a capacitance failure rate, whereas the product of the present example was completely zero.

〔The invention's effect〕

As described above, the present invention relates to a method for manufacturing a foil electrode type film capacitor in which a base end of a lead wire is welded to two electrode metal foils and wound up together with a dielectric film to form a capacitor element. After welding the lead wire to the metal foil, a two-layer laminated member made of a metal foil and an organic film is arranged and inserted so as to cover the lead wire. By winding, this laminated member is sandwiched between the films, but since the outermost part of the lead wire is covered with the organic film in the laminated member, the influence of the burr etc. of the lead wire is eliminated, and the dielectric material superimposed thereon is removed. Avoid film damage. Thereby, a withstand voltage defect can be prevented. In addition, the metal foil inside the laminated member makes contact with the electrode metal foil on both sides of the lead wire in a form that makes the lead wire a bridge, so the electrode metal foil is broken by the stress at the time of welding the lead wire. However, the electrical connection of the separated electrode metal foil is maintained, and no accident of reducing the capacitance occurs. This has a great effect of preventing an uncontrollable accident such as a sudden decrease in capacitance which has conventionally occurred during use.

Further, the present invention has an advantage that a conventional automatic winding machine can be used as it is, and there is no increase in cost, and yield and quality can be improved.

[Brief description of the drawings]

FIG. 1 (a) is a sectional view of an essential part for explaining an embodiment of the present invention, FIG. 1 (b) is an enlarged sectional view of an essential part when an electrode metal foil is cut off, and FIG. It is sectional drawing which shows the state which laminated | stacked the previous film. 1,2 ... dielectric film, 1A.2A ... aluminum foil (electrode metal foil), 3,4 ... lead wire, 5,6 ... film sheet, 10 ... laminated member, 10A ... aluminum foil, 10B …… Polyester film.

Claims (1)

(57) [Claims] In a manufacturing process of a film capacitor in which two electrode metal foils and two or more dielectric films are alternately stacked and wound, a base end of a lead wire is attached to each of the two electrode metal foils. After welding, a laminated member made of a metal foil and an organic film is inserted into the welded portion so as to cover the lead wire, with the metal foil side in contact with the lead wire, and wound up together with the dielectric film. Manufacturing method of foil electrode type film capacitor.