JPS645871Y2 - - Google Patents

Description

[Detailed explanation of the idea]

The present invention relates to improvements in metallized film capacitors, and provides a dry metalized film capacitor with extremely high safety. Conventional dry-type metallized film capacitors are made of a plastic dielectric film such as polypropylene film, polyethylene terephthalate film, polystyrene film, or polycarbonate film, coated with a metal such as aluminum or zinc, and provided with an insulating margin at the widthwise end of the dielectric film.
Vacuum-deposited metallized films with a thickness of 0.02 to 0.03 μm are stacked and wound so that the insulation margins are on the opposite side to form a capacitor element, and metals such as solder and zinc are thermally sprayed on both end faces of the capacitor element. A lead wire or a terminal was connected to the electrode lead-out portion obtained by forming a contact layer, and the capacitor was housed in a case and then sealed to form a dry metallized film capacitor. In a dry metallized film capacitor constructed in this manner, the metallized film may partially break during a voltage test due to insulation defects contained within the dielectric film or insulation defects formed during metal deposition. However, as mentioned above, the electrode is an extremely thin vacuum-deposited film, so the energy from this partial breakdown can scatter the deposited metal layer, and generally the insulation recovers and the capacitor cannot be used again. It becomes possible. However, although the deterioration of the metallized film is negligible at the initial stage, the destruction progresses little by little, with some destroyed parts as the core, and there is a risk that it will eventually catch fire and produce smoke. In order to improve such drawbacks, as shown in FIG. 1 and known in Japanese Patent Application Laid-Open No. 114219/1983, an insulating margin portion 2 is provided at the end in the width direction on at least one side of the dielectric film to form the electrode 3. At the same time, a metallized film 1 provided with insulating grooves 4 is wound so as to separate the electrode 3 into a plurality of islands in the length direction of the dielectric film, and electrode extension parts 5 are formed on both end faces of the metallized film 1. The formed metallized film capacitor is shown. However, in order to obtain a self-safety function, it is necessary to make the interval P between the insulating grooves 4 as small as possible, which has the disadvantage that the capacitance loss due to the insulating grooves 4 becomes large. Furthermore, when the capacitor capacity is large, self-heating also increases, so there is a risk of rapid breakdown due to thermal causes. Furthermore, in order to improve these improvements,
As shown in Japanese Patent Application Laid-Open No. 57-136312, there is a method of providing a thin part of the deposited film at the end of the metal spraying and scattering the deposited film at this part, but both of these methods require auxiliary masking during vapor deposition. Tape is used to partially thin the deposited film, and the equipment required to manufacture such a metallized film is complicated, making it difficult to manufacture. Depending on the conditions, the high film resistor part may easily change over time, resulting in a lack of quality stability. The present invention improves these drawbacks and provides a dry metallized film capacitor which is simple in structure, has a self-protection function, is highly stable in quality, and has good productivity. The present invention will be described below with reference to embodiments shown in FIGS. 2 to 5. Similarly to FIG. 1, an insulating margin 2 is provided at one end of the dielectric film in the width direction to form an electrode 3, and the electrode 3 is formed of a metal with a plurality of insulating grooves 4 provided in the length direction of the dielectric film. converted film 1,
A capacitor element 6 is formed by stacking and winding another metallized film 1 formed in the same manner so that the insulating margin part 2 is on the opposite side, and a contact layer is formed by metal spraying, resulting in an electrode lead-out part. After connecting terminals or lead wires to 5, the capacitor is covered with resin to form a metallized film capacitor. As shown in the figure, a weak point 3' where vapor deposited metal is likely to scatter is formed in the metallized film 1 having the insulating groove 4 near the end 2' of the insulating margin part 2 of the metallized film 1.
As shown in Fig. 4, when the dielectric film partially breaks, the weak point 3' scatters and separates the electrode 3 in that part, thereby stabilizing the self-protection function and further increasing the capacitance due to thermal contraction of the metallized film. It was possible to obtain a dry metallized film capacitor with high productivity and little loss. The above embodiment will be explained in more detail. Example Aluminum vapor deposited film resistance value 6Ω/hole, thickness 5μm
Then, insulating grooves are formed on one side of a metallized film with a heat shrinkage rate of 0 to 10% at a pitch of P = 20 mm, and the grooves are overlapped and wound so that the insulation margins are on the opposite side to create a capacitance of 20 μF. After forming a capacitor element and forming a contact layer by metal spraying, heat treatment was performed in the atmosphere, terminals were connected, and the capacitor was covered with resin. A self-safety function test was conducted on this sample after initial characteristic measurements. The results are shown in the table below.

【table】

[Table] As is clear from this result, a good self-protection function can be obtained if the thermal shrinkage rate is 1% or more, but if it exceeds 8%, the effect on the deposited metal becomes large and the tanδ This is not preferable because it will affect you.
Therefore, in order to obtain good initial properties and good self-protection function, heat treatment is performed, and the heat shrinkage rate of the metallized film is preferably 1 to 8%. As shown in Fig. 1, an insulating margin is provided at the end of the dielectric film in the width direction to form an electrode, and the electrode is connected to the electrode by providing a plurality of insulating grooves in the length direction of the dielectric film. The experiment was conducted using a metallized film in which the electrode was completely divided into multiple pieces, but the electrode was also formed by providing an insulating margin at the widthwise end of a dielectric film with a heat shrinkage rate of 1 to 8%. In addition, a metallized film separated into a plurality of islands by providing a plurality of insulating grooves in the length direction of the electrode dielectric film, and a metallized film having a heat shrinkage rate of 1 to 8.
% dielectric film with an insulating margin at the end in the width direction to form an electrode and a metallized film with the insulating margin on the opposite side and wound to form an electrode lead-out part on both end faces. Similar results were obtained for a metallized film capacitor in which the capacitor element was heat-treated in the atmosphere and then covered with a resin. Further, as shown in FIG. 5, an insulating groove 4 is provided by leaving a part of the metal thermal sprayed side vapor deposited electrode of the metallized film 1 narrow in the length direction, and a narrow width of the vapor deposited metal with a plurality of vapor deposited electrodes left is provided. Similar results were obtained for those connected to each other. Furthermore, as shown in FIG. 4, the self-safety function of the capacitor constructed as in the present invention by winding the metallized film 1 provided with the insulating groove 4 as described above is as shown in FIG. 2, the metallized film facing the metal sprayed side end of the metallized film 1 If the distance L between the end 2' of the insulation margin part 2 of 1 is 0.1 mm or more, the above effect can be produced, but if this distance L is too long, the vapor deposition electrode and the sprayed metal may come into contact. This is undesirable because it deteriorates the performance and affects reliability. Therefore, the above distance L is preferably 0.1 to 2.0 mm. Note that the above heat treatment was carried out in the atmosphere, but
Even if this is carried out in a vacuum, the thermal behavior remains unchanged and the same effect can be obtained. As mentioned above, the dry-type metallized film capacitor of the present invention is a dry type, has an extremely safe self-protection function, is highly reliable, has good productivity, and has extremely practical value. It's big.

[Brief explanation of the drawing]

Figure 1 is an exploded perspective view of the main parts of a conventional dry metallized film capacitor, Figure 2 is an explanatory diagram of the main part of the electrode arrangement of an embodiment of the dry metal film capacitor of the present invention, and Figure 3 is the heat treatment of the present invention. Fig. 4A is an explanatory diagram of the main part of the electrode arrangement of a dry-type metallized film capacitor configured with the self-safety function of the present invention; FIG. 5 is an exploded perspective view of a main part of another embodiment of the dry metallized film capacitor of the present invention. 1: metallized film, 2: insulation margin part,
3: Electrode, 4: Insulating groove, 5: Electrode extraction part, 6: Capacitor element.

Claims (1)

[Claims for Utility Model Registration] (1) An electrode is formed by providing an insulating margin at the widthwise ends of two dielectric films with a heat shrinkage rate of 1 to 8%, and at least one of the The electrode is wrapped in a metalized film with multiple insulating grooves in the length direction of the dielectric film, with the insulating margins on opposite sides, and electrode extensions are formed on both end faces, and the film is exposed to air or vacuum. A dry metallized film capacitor comprising: a capacitor element heat-treated inside; a terminal or lead wire connected to the electrode lead-out portion; and a resin sheathing the capacitor element. (2) The dry metallized film capacitor according to claim 1, wherein the insulating groove is configured to separate the electrode into a plurality of islands in the length direction of the dielectric film. . (3) The above-mentioned insulating groove is configured to separate the electrode into a plurality of pieces in the length direction of the dielectric film, leaving a part of the electrode on the metal spraying side narrow. The dry metallized film capacitor according to item 1. (4) The distance L between the metal sprayed end of the metallized film and the insulation margin end of the opposing metallized film is within a range of 0.1 to 2.0 mm. A dry metallized film capacitor according to claim 2 or 3 of the utility model registration claim. (5) The dry metallized film capacitor according to claim 4, wherein the dielectric film of the metallized film provided with the insulating groove is a polypropylene film. (6) The dry metallized film capacitor according to claim 5, wherein the dielectric film on the side facing the electrode of the metallized film provided with the insulating groove is a polyethylene terephthalate film.