JPH02285618A - Metallized plastic film capacitor - Google Patents

Abstract

PURPOSE:To obtain the title metallized plastic film capacitor having both improved current resisting property for a long period and excellent reliability by a method wherein a metallized plastic film, having a high resistance part, a low resistance film part formed on the connected side of a metallicon metal layer and another low resistance part formed on the connected side of other metallicon metal layer on the electrode, is wound around or laminated. CONSTITUTION:A capacitor element is constituted by winding around or laminating the metallized plastic film having a vapor-deposited metal film consisting of a high resistance film part 2 of 6OMEGA/square or less which is formed on the connected side of a metallicon metal layer formed at least on one side of the surface of a dielectric plastic film 1, a low resistance film part 3 of 6OMEGA/square or less formed on the connected side of the metallicon layer 5 of the above-mentioned electrode, and a low resistance film part 4 of 6OMEGA/square or less formed on the connected side of the other metallicon metal layer 5 through the intermediary of a margin part 6 located on both sides of the above-mentioned film. As a result, a metallized plastic film capacitor, having both improved current-resisting property for a long period and excellent reliability and also having strengthened connecting strength between the metallicon metal layers of both poles, can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION FIELD OF INDUSTRIAL APPLICATION The present invention relates to metallized plastic film capacitors, and in particular to current-withstanding performance 1. The present invention relates to a structure of a vapor-deposited electrode film that improves withstanding voltage performance.

Conventional technology Conventional metallized plastic film capacitors are made of a metalized plastic film in which aluminum or zinc metal is vapor-deposited with a substantially uniform film resistance as an electrode, leaving a margin on at least one side of a dielectric plastic film. They were wound or laminated to form a capacitor element.

However, in such metallized plastic film capacitors, the strength of the connection with the metallicon metal layer is affected by the film resistance of the vapor-deposited film that serves as the electrode, so current withstand performance, which is one of the performance requirements for capacitors, is affected. In order to maintain this, it was necessary to keep the membrane resistance value below a certain level. Generally, a membrane resistance value of 1 to 6 Ω/□ is often used.

Problems to be Solved by the Invention However, in recent years, as the demand for smaller capacitors, larger capacitance, higher voltage resistance, etc. has increased, high-resistance films with good self-healing performance and high potential gradient designs, and general For this purpose, a bimetalized plastic film was required for the vapor deposition electrode with a resistance of 6 to 20 Ω/□, but since the vapor deposition electrode becomes a thin film due to the high resistance film, the bonding strength with the metallicon metal layer decreases. This included the problem of poor current resistance. Therefore, as shown in Fig. 4, a structure in which a low resistance film part is formed on the metal layer connection side of the above-mentioned high resistance film is being considered, but tan δ increases in charge/discharge tests using surge current, resulting in reliability problems. was there.

Means for Solving the Problems The present invention solves the above-mentioned problems.
A high resistance film part of Ω/□, a low resistance film part of 6Ω/□ or less formed on the metallicon metal layer connection side of this electrode, and the other metallicon metal layer connection side via the margin part on the same film side. This is a metallized plastic film capacitor characterized in that a capacitor element is constructed by winding or laminating a metallized plastic film having a vapor-deposited metal film and a low resistance film portion of 6 Ω/□ or less.

In metallized plastic film capacitors, self-healing performance is good and breakdown voltage (BD
V) is significantly improved, but when the film resistance value exceeds 20Ω/□, the vapor-deposited metal film becomes easily oxidized chemically or electrochemically, so the resistance value of the vapor-deposited metal film, which becomes the effective part of the electrode, is By increasing the resistance in the range of 6 to 20 Ω/□, it is possible to design a high withstand voltage, and by increasing the thickness of the part where the vapor-deposited metal film connects with the metallicon metal layer, the connection between the metallicon metal layer is stable and good. A low resistance part of 6Ω/□ or less is formed on the other metal layer connection side via a margin on the same vapor-deposited film surface in order to further reinforce the metallicon connection of the opposite electrode. By forming the vapor-deposited metal film portion, a metallized plastic film capacitor having a stronger connection strength with the metallicon metal layers of both electrodes and good current-withstanding performance can be obtained.

EXAMPLE The present invention will be described below with reference to an example shown in FIGS. 1 to 3. In FIG. 1, on one side of a dielectric plastic film 1, there is a high resistance film part 2 which is an effective part for forming the capacitance of the vapor deposited electrode, and a low resistance film part 3 where the vapor deposited electrode is connected to the metallic layer 5. At the same time, a metallized plastic film is wound around a metallized plastic film having a vapor-deposited electrode formed with a low-resistance film portion 4 that is connected to the metallikon metal layer 5 serving as a counter electrode via a margin portion 6 on the same vapor-deposited surface side and that serves as reinforcement thereof. This is a metallized plastic film capacitor composed of FIG. 2 shows another embodiment in which a vapor-deposited electrode is not provided only on one side of the dielectric plastic film, but a low-resistance film is provided on both sides through a low-resistance film part 3, a high-resistance film part 2, and a margin part 6. This is a metallized plastic film capacitor in which the vapor-deposited electrode of the membrane portion 4 is formed and is constructed as a double-sided metallized plastic film. As a capacitor of the present invention, a polypropylene film 1 with a thickness of 7 μm and a width of 100 mm shown in FIG. A capacitor (with a rated capacity of 30 μF) formed by winding a metallized plastic film on which zinc metal is vapor-deposited to a thickness that provides a resistance value of 3 Ω/□ is attached to the other metallization junction side via the margin portion 6 as a low resistance portion. Inventive example) and comparative example: thickness 7 μm 1 width 1
A capacitor with a rated capacity of 30 μF (conventional example-1) constructed by winding a metallized plastic film in which zinc metal is uniformly deposited on one side of a 00 mm polypropylene film to a thickness that exceeds the resistance value of 10 Ω/□ (conventional example-1); As shown in Fig. 4, the high resistance film part 2, which is an effective part for forming capacitance, has a thickness of 10Ω/□, and the low resistance film part 3 has a thickness of 3Ω/□. 30
A μF capacitor (Conventional Example-2) was prototyped, and its withstand current performance and withstand voltage performance were compared and evaluated. As a current resistance test, charging and discharging were repeated 10,000 times with a surge current of 30 A/m per effective electrode length, and the change in tan δ at 1 kHz, which is a capacitor characteristic, was measured over time. The results are shown in Figure 3. Shown below.

In addition, as a withstand voltage performance test, the capacitor of the present invention was
Start applying from C300V and apply 50V every minute.
The breakdown voltage value was measured as the voltage at the time of breakdown by increasing V increments, and it was 200 to 207 V/μm.

X203V/μm and no abnormality was observed. Conventional example-1, which is a conventional metallized plastic film capacitor
As is clear from the above-mentioned examples, Conventional Example-2 differs in the shape and arrangement of the vapor deposition electrodes and cannot satisfy the long-term current withstand performance. On the other hand, in the capacitor of Example-1 according to the present invention, the charging/discharging 1
It was demonstrated that even after 0.000 cycles, there was almost no increase in tan δ at 1 kHz and it remained stable. Further, a similar test was conducted on a capacitor configured with the electrode arrangement shown in FIG. 2, and the same results as in Example 1 of the present invention were obtained.

In addition to polypropylene film, dielectric films include polyethylene terephthalate, polycarbonate,
Similar results were obtained with polystyrene, polyphenylene sulfite, or a combination thereof.
Further, the vapor-deposited metal may be not only common metals such as aluminum and zinc, but also copper, nickel, cobalt, gold, silver, or alloys thereof. Further, the same effect can be obtained even if the above-mentioned dielectric plastic film is not wound but laminated.

As clarified above, the present invention provides a capacitor with significantly improved long-term withstand current performance and excellent reliability compared to conventional metallized plastic film capacitors. .

[Brief explanation of drawings]

Figures 1 and 2 are cross-sectional views of the main parts of electrode arrangement showing different embodiments of the metallized plastic film capacitor according to the present invention, and Figure 3 is a comparison of the metallized plastic film of the present invention and the conventional example. FIG. 4, which is a characteristic diagram for a capacitor current test, is a sectional view of the main part of the electrode arrangement of a conventional metallized plastic film capacitor. 1: Dielectric plastic film 2: High resistance film part 3.4: Low resistance film part

Claims (1)

[Claims] A high resistance film part of 6 to 20 Ω/□ formed on at least one side of the dielectric plastic film, a low resistance film part of 6 Ω/□ or less formed on the metal layer connection side of this electrode, and the same film surface. A capacitor element was constructed by winding or laminating a metallized plastic film having a vapor-deposited metal film consisting of a low resistance film part of 6Ω/□ or less formed on the other metallicon metal layer connection side through the side margin part. A metallized plastic film capacitor characterized by: