JPH0121613B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a capacitor whose electrodes are taken out by metallization treatment. More specifically, the present invention relates to a capacitor in which at least one of two opposing electrodes is a vapor-deposited electrode and has a split electrode structure. Various capacitors with split electrode configurations have been devised and put into practical use. One of them is the first
It is a multilayer capacitor as shown in the figure. In the figure, 1 is a dielectric film, 2 and 2' are vapor deposited electrodes, 3 is a dielectric film, and 4 and 4' are metallicon electrodes. On the other hand, among wound-type capacitors, a capacitor with a split electrode structure as disclosed in Japanese Patent Publication No. 31-4271 is well known.
Its outline is shown in FIG. In the figure, 5 and 5' are dielectric films, 6 is a margin part, and 7 is a dielectric film.
8 is a parting line of a vapor deposited film for forming a divided electrode, and is a portion without a vapor deposited film, and 8 is one of the divided electrodes formed of the vapor deposited film. In all of these capacitors, the electrodes are taken out by metallization treatment from the A direction. However, when high voltage or high temperature conditions are applied to these capacitors, the capacitors may break down, emit smoke, or in the worst case, ignite. An object of the present invention is to provide a capacitor that does not emit smoke or catch fire due to destruction as described above. FIG. 3 shows one of the plurality of divided electrodes. In the present invention, the metallicon electrode 1 of the vapor deposition electrode 9 constituting the divided electrode
To obtain a capacitor that does not generate smoke or ignite by forming a part having a smaller current capacity than other parts, that is, a fuse part 11, near the contact part with 0 and activating this fuse when the capacitor breaks down. Can be done. Note that 12 is a margin portion. Here, "fuse current of divided electrodes" is defined. As shown in FIG. 3, a DC power supply 13 and a DC ammeter 14 are prepared, and a current i is increased between the metallic contact electrode 10 and the divided electrode 9 at a speed of 1 mA/sec, and the current when the fuse part 11 is disconnected is The value is defined as the fuse current of the split electrode. As a result of research, the inventor found that by setting the fuse current of the split electrode between 10mA and 1A,
It has been discovered that it is possible to obtain a capacitor that has sufficient characteristics as a capacitor and does not emit smoke or catch fire when the capacitor is destroyed. The following various methods can be used to form the fuse portion. (1) A method of limiting the current by providing a blank space of the vapor deposited film along the contact part of the metallicon electrode,
(2) A method of limiting current using a relatively thin vapor-deposited film with high resistance. (3) A method of limiting the current by creating scratches or cracks on the vapor deposited film along the contact area of the metallicon electrode with a special roller, etc.; (4) A method of making weak electrical contact between the metallicon electrode and the vapor deposited film to make contact. Methods include lowering the current capacity of a portion and limiting the current. First, we will show the characteristics of a capacitor with a conventional split electrode configuration. As shown in Figure 4a, polyethylene terephthalate (hereinafter referred to as PET
A film 16 (width: 70 mm, thickness: 6 μm) was prepared, and as shown in the cross-sectional view in FIG. A wound capacitor was created using the following method. Note that 15' is an undivided vapor deposition electrode, 18 is a dividing line, 19 is a margin portion, and W is a dividing width. Furthermore, as shown in FIG. 5a, split electrode pieces of PET film 21 (70 mm in length, 6 μm in thickness) with aluminum vapor-deposited on both sides as electrodes 20 and 20' are prepared, and a cross-sectional view is shown in FIG. 5b. 5μm thick
A multilayer capacitor was fabricated by layering the PP films 22 alternately and applying metallicon treatment. Both wound type and laminated type capacitors were manufactured with several types of electrode configurations, and their characteristics were investigated, and the results are shown in Table 1 below.

[Table] All of these results are after the capacitor is coated with epoxy resin.The self-safety function means that a voltage of 400 VAC is applied to the capacitor in an atmosphere of 80°C, and the capacitor is destroyed either instantaneously or after a predetermined period of time. This study was conducted to determine whether or not ignition and smoke were produced. As is clear from the results in Table 1, capacitors with conventional split electrode configurations do not have a self-protection function, and all of them ignite or ignite when destroyed. "Capacitor destruction" as used here refers to a state in which the capacitance (μF) of a capacitor has decreased to less than 80% of its rated value, and the capacitor no longer functions normally. Next, the present invention will be specifically explained using examples. Example 1 Divided vapor deposition electrode 2 as shown in FIG. 6 on one side
Prepare a PET film 24 (width 70 mm, thickness 6 μm) with double-sided aluminum evaporation with a thickness of 5 μm.
A rolled capacitor was created by wrapping it with a PP film and treating it with metallicon. In addition, 2
5 is a vapor deposited film blank area, 26 is a dividing line, and 27 is a fuse part. Next, as shown in Fig. 7, divided electrode pieces of PET film 29 (70 mm in length, 6 μm in thickness), which are double-sided vapor-deposited with aluminum as vapor-deposited electrodes 28 and 28', are prepared, alternating with 5-μm-thick PP film. A multilayer capacitor was created by layering the capacitors on top of each other and applying metallicon treatment. Reference numeral 30 indicates a vapor deposition film blank area provided only on the vapor deposition electrode 28, and 31 indicates a fuse portion.The width of the fuse portion 31, represented by d, was 2.2 mm in each case. Both wound type and laminated type capacitors were manufactured with several types of electrode configurations, and their characteristics were investigated, and the results are shown in Table 2 below.

[Table] All of these results are after being coated with epoxy resin. As described above, it was found that a capacitor in which the current path is restricted by a vapor-deposited film blank area can provide a self-protection function. On the other hand, using the same film, the dividing width W is 36 mm, d is 8 mm, and the resistance value of the aluminum vapor deposited film is 3.1 Ω/□ (the vapor deposited film thickness is 240 mm).
In the split electrode configuration shown in Å), the fuse current value of the split electrode was 1.08A. In capacitors obtained by stacking this double-sided vapor-deposited PET film (thickness 6 μm) with PP film (thickness 5 μm), the self-protection function of both the wound type and laminated type did not work, and the capacitors caught fire and emitted smoke. The capacitance of each capacitor at this time was 50 μF. Example 2 The configuration, dimensions, and arrangement of electrodes of the dielectric were as described in the fourth example.
Wound type and laminated type capacitors, which were the same as those shown in FIG. 5 and FIG. 5, were prepared in which the film resistance value of the vapor-deposited electrodes constituting the divided electrodes was high. After metallicon treatment, the test pieces were covered with epoxy resin and their characteristics were investigated. The results are shown in Table 3 below.

[Table] From this result, it can be seen that the self-safety function of the capacitor can be obtained by appropriately selecting a vapor deposited film with a high resistance value and the division width, and by setting the fuse current of the division electrode to 1A or less. On the other hand, sample No. 35, sample No. 36, sample
Even if a deposited film with a high resistance value is used as in No. 41 and Sample No. 42, if the division width is insufficiently selected, the fuse current of the division electrode becomes large and the self-protection function cannot be obtained. This example shows an example of a capacitor in which the entire surface of the vapor-deposited electrode constituting the divided electrode is a vapor-deposited film with a high resistance value, but this also applies to a capacitor in which a vapor-deposited film with a high resistance value is placed only in the fuse part. The same effect can be obtained. That is, the eighth
A capacitor with a split electrode configuration as shown in the figure was created, and the results exactly the same as those shown in Table 3 were obtained. In this case, the film resistance value of the low resistance value evaporated part is all 2.3
It was ~3.0Ω/□. In addition, in the figure, 32
33 is a low resistance vapor deposited film, 33 is a high resistance vapor deposited film (fuse part), 34 is a dividing line, 35 is a metallicon contact part, d ₁ is 1.0 mm, d ₂ is 1.5 mm, and the overall width is 70 mm. Example 3 Using a stainless steel metal roller 36 shown in FIG. 9, when passing a double-sided vapor-deposited PET film 38 over a rubber roller 37 as shown in FIG. 10, the metal roller 36 applies pressure to the vapor-deposited surface. Minor cracks or scratches. This treatment was carried out on the vapor deposition surface on which the divided electrodes were formed, and the force applied to the metal roller was 5 kg. The shape of the metal roller is 1 mm thick and 30 mm in diameter, and the end is processed to have a semicircular cross section. As shown in FIG. 11, a double-sided vapor-deposited PET film 39 (thickness 5 μm) with a split electrode structure on one side is prepared, and fine cracks 40 are formed on the split electrode side by the above process.
It was layered with a PP film (thickness: 5 μm) and wound to obtain a wound capacitor. On the other hand, by the same process, a double-sided vapor-deposited PET film (thickness: 5 μm) piece 42 with fine cracks 41 formed on only one side as shown in FIG. 12 was prepared.
A multilayer capacitor was obtained by alternately stacking PP films (5 μm thick). Table 4 below shows the results of studies using films with various vapor-deposited resistance values for both wound and laminated capacitors.

[Table] From this result, it can be seen that the self-safety function of the capacitor can be obtained by appropriately setting the thickness of the deposited film and the division width. Example 4 In the process of creating a capacitor with the dielectric structure and electrode structure shown in FIGS. 4 and 5, a thin layer of silicone oil (50cst) was applied to the end of the electrode where the split electrode contacts the metallicon electrode, and a wound shape was formed. Then, we created a multilayer capacitor, treated it with metallicon, packaged it with epoxy resin, and then investigated its characteristics. Here, we investigated capacitors with split electrode configurations with various membrane resistance values. Its properties are shown in Table 5 below.

[Table] As can be easily seen by comparing Tables 1 and 5, silicone oil treatment can weaken the contact between the metallicon electrode and the deposited film.
It can be seen that the self-safety function works by lowering the fuse current of the split electrode. Furthermore, the same effect can be obtained not only by silicone oil treatment but also by methods such as taking into account the heat treatment temperature of capacitor elements treated with metallicon. If the fuse current of the split electrode is less than 10 mA, the capacitance will decrease during operation, making it unsuitable for use as a capacitor. Furthermore, by the method shown in the example, a capacitor with a self-safety function can be obtained by setting the fuse current of the split electrode between 10 mA and 1 A.
In addition to using the methods shown in the examples alone, it is also possible to use multiple methods in combination. Although the above embodiment shows the case of a dry type capacitor, the same effect can be obtained in the case of an oil-immersed wet type capacitor. Also, as a dielectric film,
An example of a film obtained by vapor deposition on a PET film has been shown, but this may be a PP film or other dielectric films such as paper, polyethylene film, polystyrene film, etc. Furthermore, although we have shown an example in which one side has a split electrode structure, this is also possible with split electrodes on both sides.
It may be an aluminum foil electrode with a thickness of about 20 μm, or it may be constructed by stacking dielectric films deposited on one side instead of using dielectric films deposited on both sides as in the embodiment. In addition to the aluminum used in the examples, the vapor deposition material may also be other materials such as zinc, tin, copper, lead, indium, etc., and for wound type capacitors, it may have a structure wound around a core. A flat type without a core may also be used. Furthermore, regarding the winding core, in addition to hard cores such as plastic, sponge,
It is also possible to use a soft core such as paper.
In addition, in Example 2, an example was shown in which the current path (portion that functions as a fuse) was concentrated in one place in the blank part of the vapor deposited film, but this does not necessarily have to be concentrated in one place, but in the case of multiple places as shown in FIG. The same effect can be obtained even if it is dispersed. In the figure, 43 is a vapor deposited film blank area, and 44 is a fuse part. As described above, according to the present invention, even if the capacitor breaks down, a safe capacitor that does not emit smoke or catch fire can be provided at a low cost, and its industrial efficiency is great.

[Brief explanation of drawings]

Figure 1 is a perspective view of a multilayer capacitor, Figure 2 is a perspective view of a wound capacitor with a split electrode configuration, and Figure 3 is a perspective view of a wound capacitor with a split electrode configuration.
The figure is a plan view of one divided electrode in the present invention, FIG. 4a is a plan view of a conventional vapor-deposited film, and FIG. 4b
is a cross-sectional view taken along the line X-X' in FIG. 4a, FIG. 5a is a perspective view showing one electrode piece of a conventional multilayer capacitor, and FIG. 5b is a cross-sectional view of a part of the same multilayer capacitor. , FIG. 6 is a plan view of an embodiment of a vapor-deposited film in the present invention, FIG. 7 is a perspective view showing an embodiment of one electrode piece of a multilayer capacitor in the present invention, and FIG. 8 is a plan view of an embodiment of a vapor-deposited film in the present invention. FIG. 9 is a plan view of another embodiment of the film, FIG. 9 is a side view of a metal roller, FIG. 10 is a cross-sectional view of a part of an apparatus for cracking a vapor deposited film with a metal roller, and FIG. 11 is a vapor deposited film according to the present invention. FIG. 12 is a perspective view showing another embodiment of one electrode piece of the multilayer capacitor according to the present invention;
FIG. 13 is a plan view of still another embodiment of the vapor-deposited film of the present invention. 9, 23, 28, 28'... Vapor deposition electrode, 10...
...Metallic electrode, 11, 27, 31, 44...
Fuse part, 12... Margin part, 24, 29...
...Dielectric film, 26, 34...Parting line, 2
5, 30, 43... Vapor deposited film blank area, 32... Low resistance value vapor deposited film, 33... High resistance value vapor deposited film, 35...
Metallicon contact portion, 38, 39, 42...Double-sided vapor deposited dielectric film, 40, 41...Crack.

Claims (1)

[Claims] 1. At least one of the two opposing electrodes is a vapor deposition electrode, and has a plurality of divided electrode structures, and each of the divided electrodes has a fuse current value in the range of 10 mA to 1 A. A capacitor characterized by: 2. Claim 1, characterized in that the fuse current value of the divided electrode is set by the vapor deposited film blank area along the metallicon contact portion on the divided electrode.
Capacitors listed in section. 3 The current path formed by the vacuum space of the deposited film is 1.
A capacitor according to claim 2, characterized in that the capacitor is concentrated in one place. 4. The capacitor according to claim 2, wherein the current path formed by the vapor-deposited film blank portion is distributed at a plurality of locations. 5. The capacitor according to claim 1, wherein the fuse current value of the divided electrode is set by forming a thin vapor deposited film portion at least in the fuse portion. 6. The capacitor according to claim 1, wherein the fuse current value of the divided electrode is set by forming a series of fine cracks or flaws at least in the fuse portion. 7. Claim 1, characterized in that the fuse current value of the split electrode is set by applying silicone oil to at least the fuse portion to maintain a certain level of contact with the metallicon electrode.
Capacitors listed in section. 8. The capacitor according to any one of claims 1 to 7, wherein the fuse portion of the divided electrode is located at a position overlapping the margin portion of the counter electrode. 9. The capacitor according to any one of claims 1 to 8, wherein the divided electrode is set on the wound capacitor. 10. The capacitor according to claim 9, wherein the wound capacitor is a flat capacitor without a winding core. 11. The capacitor according to any one of claims 1 to 8, characterized in that the divided electrodes are constructed as a multilayer capacitor.