JPS612313A - Laminated metallized film 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 the Invention The present invention relates to large capacity multilayer metallized film capacitors.

(Conventional configuration and its problems) In recent years, demands for safety have increased for all types of equipment, and safety has also become important for capacitors.

The safety of capacitors is to prevent the possibility of smoke or fire in the event of an abnormality. To ensure safety, there are two types of capacitors: one in which a safety device is added to the capacitor, and the other in which the capacitor itself has a safety function.

Compared to those with the latter safety function, a capacitor with the former safety function has a larger volume as a whole, requires more assembly man-hours, and is more expensive. Things are layered.

FIG. 1 is a perspective view of a conventional multilayer metallized film capacitor element, and FIG. 2 is a plan view of the same electrode. In Fig. 1, 1 is a double-sided metal-deposited threshold electric film, 2 is a dielectric laminated film, 3 is a metal spray layer for drawing out the electric current, 4 is a metal-deposited surface, and 1.5°5a is a part from which the deposited film is removed. be.

Conventional multilayer capacitors have a structure consisting of a collection of microcapacitors, so when dielectric breakdown occurs between opposing electrodes at a certain point, a short circuit current flows into the microcapacitors involved in the dielectric breakdown, causing a second By scattering the electrical weak points of width B provided at each pitch A in the figure (current flows through these parts), the electrode at the broken part is electrically isolated from the main body and released, and other This reduces the negative impact on the micro capacitor group. With this function, even if an abnormal voltage is applied to the capacitor or the surrounding temperature becomes abnormally high, the capacitance will simply decrease, thereby preventing smoke or ignition. Hereinafter, this function will be referred to as a security function.

However, in a laminated metallized film capacitor that has this safety function, the electrical weak point of width B must be blown away by the short circuit current flowing into the micro capacitor that is involved in dielectric breakdown. It is required that the charging/discharging current flowing in and out of the capacitor does not scatter, and therefore the capacitance of the microcapacitor must be limited to a certain value or less. Therefore, the laminated metallized film capacitor has the disadvantage that the cutting width C becomes longer (25 mm or more) as the capacitance increases, and the operability of the safety function deteriorates.

As a solution to this drawback, there are methods shown in FIGS. 3 and 4. FIG. 3 is a perspective view of a large-capacity laminated metallized film capacitor, and FIG. 4 is a plan view of the same electrode. In the figure, D is the divided electrode width, E is the width of the electrical weak point, and F is the cutting width.

That is, in advance, a portion 5 from which a vapor deposited film has been removed is formed on each vapor deposited electrode belonging to at least one electrode group of two vapor deposited electrode groups facing each other at a desired interval E parallel to the metal sprayed layer 3 for drawing out the electrode. A laminated metallized film capacitor has been proposed, which has an electrode structure in which a T-shaped deposited film removed portion 5b is provided at right angles to and continuous with the deposited film removed portion 5. This has made it possible to create a large-capacity multilayer metallized film capacitor with a safety function that keeps the capacitance of the microcapacitor below a certain value even when the cutting width becomes long. In addition, in this specification, the electrode between the vapor-deposited film removal parts perpendicular to the vapor-deposited film removal part 5 is called a divided electrode for convenience.

Also, in this large-capacity laminated metallized film capacitor, as shown in FIGS. 3 and 4, the vapor deposited film removal parts 5 and 5b are continuous.
As shown at 6 in FIG. 4, vapor deposited electrodes that are electrically isolated from the electrode body are created at both ends of the electrode by cutting, resulting in a large capacity loss and a disadvantage in cost.

(Object of the Invention) An object of the present invention is to eliminate the drawbacks of the conventional example and to provide a large-capacity multilayer capacitor with little capacitance loss and a safety function.

(Structure of the Invention) The laminated metallized film capacitor of the present invention has a metallized film capacitor intermittently disposed on each vapor-deposited electrode belonging to at least one electrode group of two opposing vapor-deposited electrode groups at regular intervals in the length direction. A plurality of first vapor deposited film removing parts are provided in the first vapor deposited film removing part, and a second vapor deposited film removing part is provided at a position between the first vapor deposited film removing parts so as to be perpendicular to the first vapor deposited film removing part so as not to communicate therewith. be.

(Description of Embodiment) An embodiment of the present invention will be described based on FIGS. 5 and 6.

FIG. 5 is a perspective view of a laminated metallized film capacitor according to the present invention, and FIG. 6 is a plan view of the same electrode.

In the figure, G is the width of the divided electrode sandwiched between the second vapor deposited film removed parts, H is the width of the electrical weak point between the first and second vapor deposited film removed parts, and G is the cutting width.

In other words, in order to eliminate split electrodes that are electrically cut off by cutting in conventional large-capacity laminated metal film capacitors, the width is 1/2 the width B of the electrical weak point shown in FIG. 2 of the conventional example. A second vapor deposited film removing section 5c is provided at both ends of the first vapor deposited film removing section 5 through H, perpendicular to the first vapor deposited film removing section 5 and without any communication therewith, and cutting is performed at any position of the divided electrode. Even if this is done, all the divided electrodes remain electrically connected to the electrode body.

Double-sided vapor deposited polyethylene terephthalate film (thickness 5
In the electrode structure of FIGS. 2, 4 and 6 using .mu.m), A=D=G=10 yuan.

B = E = 2 + m +, H = 1 rm, a polypropylene film (thickness 5 μm) was wound up as a laminated film on a drum of φ = 800 Ma for 3000 turns, and then metal sprayed layers for electrode extraction were formed on both end faces of the film. A laminated metallized film capacitor was prototyped by cutting the capacitor matrix at C=F=I=30 mm.

Table 1 shows the capacity of each prototype after cutting, the capacity ratio between the prototype according to the present invention and the conventional prototype, and the safety function operation rate.

As shown in the table, it can be seen that in a laminated metallized film capacitor with a cutting width of 25 mm or more, split electrodes must be provided in order to achieve a safety function operating rate of 100%.

Furthermore, it can be seen that even in the case where split electrodes are provided, the capacitance loss is smaller in the embodiment according to the present invention than in the conventional example.

(Effects of the Invention) According to the present invention, it is possible to provide a laminated metallized film capacitor with less capacitance loss without impairing the safety function, and the effect is significant.

[Brief explanation of drawings]

Figure 1 is a perspective view of a conventional laminated metallized film capacitor, Figure 2 is a plan view of the same electrode, Figure 3 is a perspective view of a conventional large capacity laminated metallized film capacitor, and Figure 4 is the same electrode. FIG. 5 is a perspective view of a laminated metallized film capacitor according to the present invention, and FIG. 6 is a plan view of the same electrode. 1...Double-sided metal evaporated dielectric film, 2...
Dielectric laminated film, 3...Metal sprayed layer for electrode extraction, 4 Metal vapor deposition surface, 5, 5a, 5b. 5c... Vapor deposited film removal part, 6... Split electrode cut off from the electrode body, A, D, G - Split electrode width, B, E
, H... Width of electrical weak point, C, F. ■ Cutting width. Patent applicant Matsushita Electric Industrial Co., Ltd. Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6

Claims (1)

[Claims] Each vapor-deposited electrode belonging to at least one electrode group of two vapor-deposited electrode groups facing each other with the dielectric film in between has a plurality of first vapor-deposited film removal parts at predetermined intervals in the length direction of the dielectric film. A laminated metallized film capacitor, further comprising a second vapor-deposited film removed part between each of the first vapor-deposited film removed parts in a direction perpendicular to the first vapor-deposited film removed parts and not continuous therewith.