JPS6037612B2 - multilayer capacitor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides the following advantages:
This invention relates to a large-capacity multilayer capacitor equipped with a protection function in the event of dielectric breakdown.

For example, as shown in FIG. 1, a multilayer capacitor is made by alternating double-sided metallized films in which metals (electrodes) 2, 2' such as aluminum are deposited on both sides of a dielectric 1 such as a polyethylene terephthalate film, and non-deposited films 3. The capacitor base body 5 is constructed by forming contact layers 4, 4' on both end faces of the contact layers 4, 4' by metal spraying, and then cutting them into a predetermined width using a cutter, and attaching lead wires to the contact layers 4, 4'. It is manufactured by a method such as tying and then covering with resin.

Such a multilayer capacitor has a structure in which each electrode is divided into small electrodes, and these are assembled into a group of two electrodes by a contact layer. For this reason, if a dielectric breakdown occurs in a capacitor for some reason and an abnormal current flows, the vapor deposited film will scatter near the contact layer due to Joule heat, and the entire electrode will be disconnected one after another at the moment of breakdown. It has a protective function that prevents smoke and ignition as seen in wound type capacitors.
However, there is a restriction that the cutting width must be 25 mm or less in order to exhibit its function, which has been a problem in manufacturing large-capacity capacitors. FIG. 2 shows a large capacitance capacitor manufactured under such conditions, in which small capacitance elements 6 are made and several of these are connected in parallel to increase the capacitance.

This method has the disadvantage that it requires too much man-hours. Another way to increase the capacity of a multilayer capacitor is to increase the electrode facing width or the number of laminated layers, but even then, the cutting width still needs to be widened. The present invention solves the above problems and provides a large-capacity multilayer capacitor having the above-described protective function.

The present invention will be explained below with reference to the drawings.

FIG. 3 shows a stacked double-sided metallized film in a plan view, and non-deposited films and the like are omitted for clarity.

In the figure, 11 and 11' are vapor deposition electrodes formed on both sides of the concession film, 12 and 12' are vapor deposition margins, and 13
, 13' are contact layers, and 14 is a portion where both electrodes 11, 11' face each other. Under such a configuration, the present invention provides that the electrodes 11, 11' extend at least the entire width of the opposing region 14 in a direction perpendicular to the contact layers 13, 13', and also perpendicular to the electrode surface. Long holes 15 in the direction are formed in both the double-sided metallized film and the non-deposited film. Therefore, the elongated hole 15 has one margin 12
It starts from inside and ends within the other margin 12', but the shorter the distance between the tip of the elongated hole 15 and the contact layers 13, 13', the more effective it is. Long hole 15 and closest hole 15
The distance between the two must be below the limit of the cutting width mentioned above, that is, below 25 sides. By forming the elongated hole 15, at the moment when a large current flows due to dielectric breakdown, a part of the vapor deposited film 16, 16' is scattered between the tip of the elongated hole 15 and the contact layers 13, 13'. The structure becomes completely separated, similar to the parallel connection of capacitive elements 4 shown in FIG. 2, and then the vapor deposited film 17 in the contact layer portion between the long holes 15 is scattered and broken.

Therefore, the distance between the long holes 15 and 15 is kept below the limit,
By forming a large number of long holes 15, the capacitance can be increased. Formation of the largest hole 15 can be performed relatively easily by using laser light.

FIG. 4 is a diagram showing another embodiment of the present invention.

This is done so that the slot 15 starts from the contact layer 13' on one side and ends within the margin 12' on the opposite side, and the slot 15
The contact layers 13' separated by are connected by lead wires 18 so as to have the same potential.
Although the effect is similar to that shown in FIG. 3, the elongated hole 15 is easily formed, there is no need to use a laser beam, and a cutting machine using an ordinary milling cutter can be used. However, the lead wire is attached)
It becomes complicated. As described above, the present invention provides a large-capacity laminated film having long holes in the double-sided metallized film extending in the direction of the contact layer over at least the entire range where electrodes of opposite polarity face each other, and having a protective function in the event of dielectric breakdown. The present invention provides a capacitor that can be applied to the same machine not only when using a double-sided metalized film but also when using a single-sided metalized film.

Next, specific examples of the present invention will be described.

A double-sided metallized film with aluminum vapor-deposited on both sides of a polyethylene terephthalate film with a thickness of 6 mm and a width of 4 mm, and a polypropylene film with a thickness of 6 mm are wound for 1200 turns on a bobbin with an outer diameter of 200 mm. The end face of the capacitor was coated with metal to form a ring-shaped capacitor base. From this capacitor matrix, capacitors of the type shown in Fig. 3 and capacitors of the type shown in Fig. 4 were manufactured using a Caesar cutting machine and a cutting machine using a milling blade. At this time, long holes were also formed in the polypropylene film.
The width of the long hole is 1.2 Yanagi, the distance between the long hole and the closest hole, the so-called cutting width, is 22 ribs, and the distance between the tip of the long hole and the contact layer is 1.
．． On the 5th side, three long holes were provided, and the capacitance was 25 peaks F. All lead wires were attached by soldering, and the exterior was made using a resin case and epoxy resin. The protection function test is
AC350V was applied in an atmosphere of 850°C to forcibly cause dielectric breakdown, and the presence or absence of smoke was examined at that time. For comparison, a 25°F sample without long holes was also tested. The results are shown in the table below, which confirms the excellent protection function of the capacitor according to the present invention.

As is clear from the examples above, the present invention not only enables the production of large capacity capacitors with built-in protection functions, but also enables
・It has many effects such as moldization, man-hour reduction, and cost reduction, and is of great industrial and practical value.

[Brief explanation of the drawing]

Fig. 1 is a perspective view of a capacitor base for explaining the manufacturing method of a general multilayer film capacitor, Fig. 2 is a schematic diagram showing connections when manufacturing a conventional large capacity capacitor, and Fig. 3 is a diagram according to the present invention. FIG. 4 is a schematic diagram for explaining one embodiment of a multilayer capacitor, and FIG. 4 is a schematic diagram for explaining another embodiment. 11, 11'... Electrode, 12, 12'...
...Margin, 13, 13'...Contact layer, 14...
...Portion where exposed electrodes face, 15...Elongated hole, 18.
…··Lead. Figure 1 Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] 1. In a multilayer capacitor formed by laminating a metalized film on one side or a metalized film on both sides and a non-deposited film, electrodes of opposite polarity are provided with respect to the contact layer over at least the entire width of the opposing portion. The single-sided metallized film has long holes in a direction perpendicular to the electrode surface and perpendicular to the electrode surface.
Or a multilayer capacitor characterized in that it is formed on a double-sided metallized film and a non-evaporated film. 2. Claim 1, characterized in that one end of the elongated hole starts from one contact layer, and the contact layers separated by the elongated hole are all connected by lead wires so that they have the same potential. Multilayer capacitors listed in section.