JPH0420244B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a capacitor having a structure in which electrodes are taken out by metal spraying. Specifically, at least one of the two opposing vapor-deposited electrodes is a split electrode, and along the edge of the split electrode where the metal is sprayed, other vapor-deposited electrode parts are formed in strips, lines, or intermittently. This invention relates to a capacitor with a so-called self-safety mechanism added by providing a vapor-deposited electrode portion with a smaller current capacity.

(Structure of conventional example and its problems) Conventionally, as an example of a capacitor having a split electrode structure, a capacitor using a metallized dielectric as shown in FIG. 3 has been proposed. In this method, divided electrodes 1 are provided on a dielectric material such as paper or plastic film by vapor deposition of a metal such as aluminum or zinc, and these are electrically separated by a vapor-deposited insulation margin 2 and an insulation groove 3 (hereinafter referred to as the division margin). It is divided into parts, and the electrodes are taken out by spraying metal along the electrode edges 4, respectively.

Further, as a second example of the conventional example, the one shown in FIG. 4 has also been proposed. This is an improved example of the one shown in FIG. 3, and was devised to obtain a more sufficient operation of the self-security mechanism. The content is that vapor deposition electrode blank parts (evaporation electrode removed parts) 5 are provided intermittently in the longitudinal direction along the edge of the electrode where the metal is sprayed, and a part of the dielectric material is destroyed. When this occurs, a current is supplied from the electrode edge 4 to which metal is sprayed, and each evaporation electrode blank part 5
The electrode density between the electrodes is increased, and when a current exceeding that which the deposited film can tolerate flows, the deposited film between each deposited electrode blank part 5 acts as a fuse and scatters, cutting off the current from the metal spraying side. As a result, the expansion of the destroyed portion is prevented, and a so-called self-safety mechanism operation is obtained.

In a capacitor having a self-safety mechanism of a conventional vapor-deposited electrode pattern as described above,
It was found that it has the following shortcomings in terms of service life. This is because the contact surface of the wound body with the metal sprayed part becomes uneven due to winding variations that occur when the dielectric material is wound, resulting in split electrode parts that do not have sufficient connection with the metal sprayed part. As a result, the self-safety mechanism may operate excessively, resulting in a reduction in capacity and a life span that cannot be guaranteed.

This phenomenon is more common in capacitors installed in parallel on the power supply side, which are mainly used to improve the power factor of lighting discharge lamps, than in capacitors installed in series with the coil, such as those for motor operation. Occur. This is due to the surge voltage that occurs instantaneously when the power switch is turned on to a device that has a capacitor installed, and when a capacitor is installed in series with a coil, the surge voltage is easily absorbed by the coil. On the other hand, the surge voltage is directly applied instantaneously to a capacitor connected directly in parallel with the power supply, and if there is a small vapor-deposited split electrode that is not sufficiently connected to the metal sprayed part (metallicon), it will be disconnected at the connection surface. This is to be done.

(Objective of the Invention) The present invention provides sufficient self-protection even if there is a slight unevenness on the end face of the wound body, which does not cause a decrease in capacity due to over-activation of the self-protection mechanism, and even if an abnormality occurs inside the dielectric. The purpose of this study is to obtain a vapor-deposited electrode pattern for a capacitor that provides mechanical operation.

(Structure of the Invention) The structure of the vapor-deposited electrode pattern of the present invention will be explained below with reference to the drawings.

First, FIGS. 1 and 2 show vapor deposited electrode patterns of the present invention corresponding to the conventional examples shown in FIGS. 3 and 4, respectively. The dividing margin 3 according to the conventional example shown in FIGS. 3 and 4 extends all the way to the electrode edge 4 where the metal is sprayed, forming a complete dividing margin, and each is electrically completely independent. This constitutes subdivided power 1. On the other hand, the vapor deposited electrode pattern according to the present invention shown in FIGS. 1 and 2 has a dividing margin 3a that divides the electrode by leaving a width l=0.25 to 3.0 mm from the electrode edge 4 where the metal is sprayed. The conventional dividing margins 3 are mixed (for example, alternately), and therefore the small divided electrodes 1a
and 1b form subdivided electrode groups that are electrically connected by a width l and are not completely independent, and the subdivided electrode groups are vapor deposited electrode patterns that are not completely electrically connected due to a dividing margin 3. It consists of

As described above, by configuring the vapor-deposited electrode pattern according to the present invention, the substantial contact distance L with the metal sprayed portion per divided electrode becomes longer than that of the conventional example. This welding section distance L needs to be appropriately set depending on the length of the wound electrode, the distance, the shape of the outer diameter of the wound element, etc.

(Description of Examples) Hereinafter, the present invention will be specifically described using Examples.

Polypropylene (hereinafter referred to as PP) as a sample
Using a single-sided vapor-deposited film with a film thickness of 5 μm and a width of 80 mm, the vapor-deposited electrode pattern shown in Figure 2 was placed on one side.
Constructed of PP single-sided vapor deposited film. Here, the vapor-deposited metal is aluminum and the vapor-deposition resistance is within the variation range of 3.0 to 4.0 Ω/□, and the distance between each division margin 3 and 3a is 50 mm, and the distance between the metal sprayed part per sub-division electrode group is set at 50 mm. Contact section distance L = 100mm,
In addition, assuming that the ratio of the vapor deposition electrode blank area (evaporation electrode removed area) 5 in each subdivided electrode group is 85%, only the l dimension is 0 to 0.25 mm, 0.25 to 0.75 mm, 0.75 to 1.25 mm,
1.25~2.0mm, 2.0~3.0mm, 3.0~5.0mm and above 6
Classified into different types of evaporation electrode patterns, each
A wound element with a capacitance of 50 μF was made, the edges were sprayed with metal, the electrodes were taken out, and the samples were packaged with two-component thermosetting epoxy resin for life tests and safety mechanism operation tests. For each purpose, n = 20 units were manufactured.

First, in order to confirm the lifespan, we conducted a forced charge/discharge short-circuit test, which is extremely demanding, in order to examine the electrical connection strength between each vapor-deposited split electrode and the metal sprayed part (metallicon) against surge voltage. The test conditions were 400 VDC charging/discharging short-circuiting, the capacitance was measured each time, and the rate of change in capacitance with respect to the pre-test (initial capacitance value) was calculated and plotted in the graph shown in FIG. From this test result, it can be seen that when l=0 to 0.25 mm, which is close to a complete division margin, the electrical connection strength between the metal sprayed part and each vapor-deposited divided electrode against surge voltage is weak and the electrical connection strength is large and unstable. Similarly, as a confirmation of the mounting test, we conducted 100,000 intermittent cycles of 2 sec ON - 2 sec OFF with an electromagnetic switch connected directly to the AC 220 V power supply line in parallel, and data showing a similar trend was obtained.

Next, we conducted an operation test of the self-safety mechanism. The test conditions were to place each sample in a constant temperature chamber with an atmosphere of 100℃, increase the voltage of AC400 to 600V in steps of AC50V every 30 minutes, and ensure that the rate of change in capacity was -80% or less compared to the initial capacity value. A graph showing the tabulation for each l-dimensional block is shown in FIG. 6 as a sample with no smoke, no ignition, and no cracks on the capacitor exterior. It can be seen that the safety mechanism operation rate decreases when l=3.0 mm. This result is due to the fact that as the l dimension increases, the substantial proportion of the evaporation electrode blanks 5 provided intermittently in the longitudinal direction of the electrode in the divided electrode increases, and no fuse action occurs. This result can be compensated to some extent by increasing the ratio of the vapor deposition electrode blank portion 5 to the divided electrodes.

Judging comprehensively from the results of the charge/discharge short-circuit test and the safety mechanism operation test, we found that by setting l = 0.25 to 3.0 mm and configuring a vapor deposited electrode pattern with a mixture of margin 3a that is not a complete division margin, the actual The connection distance between the single-segment electrode and the metal sprayed part has been increased, making it possible to compensate for insufficient contact due to variations in the unevenness of the element end face, and also to prevent momentary surge voltages. It is possible to provide a capacitor that exhibits little capacitance reduction, has a guaranteed lifetime, and fully satisfies the operation of its self-protection mechanism.

In the above embodiments, only the vapor deposition electrode pattern shown in FIG. 2 has been described, but exactly the same improvement effect can be obtained with the vapor deposition electrode pattern shown in FIG. 1. In addition, the vapor-deposited electrode pattern according to the present invention may be provided on one side of a double-sided vapor-deposited film, and the dielectric material may be PET film, PP film, polycarbonate, polystyrene, or other film or paper, and the vapor-deposited metal may be zinc in addition to aluminum. , copper, tin, and other metals. In addition to a wound type capacitor, a multilayer type capacitor may also be used.

(Effects of the Invention) As described above, according to the present invention, it is possible to provide a capacitor with a sufficient self-protection mechanism that is highly reliable and has little capacity reduction even in response to inrush surge voltage due to switching. There are big things in industry.

[Brief explanation of drawings]

1 and 2 are plan views of a dielectric vapor deposited electrode pattern having a self-safety mechanism according to the present invention, and FIG.
4 is a plan view of a dielectric vapor-deposited electrode pattern having a conventional self-protection mechanism, and FIG. FIG. 6 is a diagram showing the results of a safety mechanism operation test for each l dimension using a vapor deposited electrode pattern according to the present invention. 1... Vapor deposition split electrodes, 1a, 1b... Small vapor deposition split electrodes with electrical connection, 2... Vapor deposition insulation margin, 3... Complete split margin, 3a... Division margin with l dimension left, 4... Metal spraying (Metallicon) 5... Vapor-deposited electrode blank area.

Claims (1)

[Scope of Claims] 1. A capacitor in which at least one of the electrodes facing each other via a dielectric is provided with a plurality of division margins running in the width direction, and the plurality of division margins completely separate the deposition electrodes. 0.25~ on the split margin and the edge of the electrode on the side to be metal sprayed
A capacitor comprising a dividing margin that divides a vapor deposited electrode leaving 3.0 mm, and the vapor deposited electrode has a plurality of subdivided electrode groups in the longitudinal direction. 2. The capacitor according to claim 1, characterized in that a vapor-deposited film blank portion is provided in the longitudinal direction of the electrode along the side on which the metal is thermally sprayed.