JPS62183507A - Manufacture of laminated capacitor - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a method of manufacturing a multilayer capacitor.

BACKGROUND OF THE INVENTION In recent years, film capacitors have become smaller and more laminated.As shown in FIG.
The dielectric film 4 is wound to form a base capacitor.
In this case, the general method is to wrap a thick protective film 2 at the beginning and end of each x-7 winding of the base material of the capacitor (metallized film 3, dielectric film 4). . After winding a predetermined number of turns, a metallized silicone 6 is applied to the end face of the base capacitor for drawing out external electrodes, and heat treatment is performed to stabilize the characteristics. At this time, the method of tightening the metal band 7 on the outside of the base capacitor and heat treatment is used because this method provides much more stable characteristics than heat treatment in a free state. After the heat treatment has been completed, the band 7 and drum 1 are removed from the base capacitor, and the capacitor is cut to a predetermined capacitance to produce a multilayer capacitor element. After attaching terminals to the element, it is inserted into a case and potted with sealing resin to create the desired multilayer capacitor.

Problems to be Solved by the Invention However, among the above-mentioned manufacturing methods, stabilizing the characteristics by tightening metal bands before heat treatment can reduce the extent of capacity reduction during service life, and improve the electrical resistance after cutting. This has a very good effect on improving pressure resistance, etc., but due to management of band tightening pressure, generation of a gap between the base capacitor and the metal band due to metallization, and thermal expansion of the metal band 7 due to heat, The base capacitor is not tightened with little variation.

Means for Solving the Problems Therefore, in order to eliminate the above-mentioned drawbacks, the present invention provides a base material (metalized film, dielectric film) of the base capacitor.
After winding the capacitor, paper is wound and the base capacitor is cut to form a capacitor element.

Effect: According to the above method, during heat treatment, the diameter of the metal drum increases due to thermal expansion.

Further, since the base material is a thermoplastic plastic film, a force of thermal contraction acts toward the center of the drum, but thermal expansion occurs in the thickness direction of the film, that is, the thickness of the base capacitor. At this time, the paper wrapped at the end of the base capacitor has a much smaller coefficient of thermal expansion than metal or plastic, so the base capacitor is sandwiched between the metal drum and the paper and tightened uniformly. Also, after winding the paper,
Unlike metal bands, it is not affected by metallicon burrs because it is coated with metallicon. Furthermore, after heat treatment, the base capacitor can be cut without removing the band, and a desired multilayer capacitor element can be produced, thereby simplifying the process.

In addition, if the winding is uniform and strong, there will be less loosening of the element when cutting the mother capacitor, and the cut surface will be firmly fixed, allowing voltage to be applied to the cut surface and restoring electrical insulation. When this happens, there is less self-healing and less damage to the element. In addition, when the characteristics change during service life, if the film layers are tightly tightened evenly,
The gap layer between the film layers becomes smaller, and the amount of air that causes oxidation of the deposited metal, which is the electrode of the capacitor, can be reduced. As a result, the capacitance change during life is reduced.

Example Examples of the present invention will be described below.

In Fig. 1, 1 is a metal bobbin, and a protective film 2 is wound around this 6 beso metal bobbin 1, and a double-sided metallized film (using a polyester film with a thickness of 6 μm) 3 and a dielectric film ( (7) Polypropylene film 4 with a thickness of 6 μm is wound alternately, and after this winding, a paper 6 with a thickness of 50 μm is wound 10 times to form a base capacitor. After that, heat treatment at 120°C for 10 hours, then cut and divide to make 10 μF elements, and seal them with resin to make a multilayer capacitor.0 Decrease in capacitance when a voltage of 250 VAC is applied to this multilayer capacitor. Figure 3 shows the change over time. From this Figure 3, the capacity reduction after 1000 hours is -1.5% for the example product, while it is -2.3% for the conventional product, and it is difficult to wind the paper 6 at the end of the winding. It has been demonstrated that this strengthens the tightness between the metallized film 3 and the dielectric film 4, reduces the interlayer void layer, and as a result, reduces oxidation of the vapor-deposited metal, which is the capacitor electrode, and prevents a decrease in capacitance. Figure 4 shows the rate of change in capacitance when a voltage is applied to recover the electrical insulation of the cut surface after cutting. With conventional products, when a voltage is applied, large self-healing occurs on the cut surface, a large inrush current flows, and the contact between the metallicon and the vapor-deposited electrode melts due to Joule heat, separating the capacitor electrodes and reducing the capacitance. ing. On the other hand, this commercial product has less capacity reduction and less variation.

Effects of the Invention As described above, in the present invention, by winding paper at the end of the winding of the base capacitor, the winding is uniform and the winding is strong. This has a great effect in reducing the rate of change in capacity of the battery and reducing capacity loss during service life. moreover,
This eliminates the conventional process of tightening metal bands, and provides a more rational construction method.

[Brief explanation of drawings]

FIG. 1 (=) is a perspective view of a base capacitor in the manufacturing process of a multilayer capacitor showing an embodiment of the present invention, FIG. Figure 2 (a) is a perspective view of the base capacitor in the conventional manufacturing process of multilayer capacitors.
Box) is a perspective view of a capacitor element obtained by cutting the same base capacitor, Figure 3 is a diagram showing the capacitance change rate over the life of the capacitors according to the above embodiment and the conventional example, and Figure 4 is the cut-off withstand voltage of the same capacitor. FIG. 3 is a diagram showing the rate of change in capacity before and after. 1...Metal bobbin, 3...Double-sided metal film, 4...Dielectric film, 6...
·paper. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure (α'<b Figure 2

Claims (1)

[Claims] A method for manufacturing a multilayer capacitor, in which a capacitor is obtained by winding metallized films or a metallized film and a dielectric film around a bobbin, and paper is wound around the end of the winding of the base capacitor, and the base capacitor is cut to form a capacitor element.