JPH0410519A - Aluminum electrolytic capacitor - Google Patents

Abstract

PURPOSE:To prevent anode foil and cathode foil from short-circuiting even when buckling occurs in the vicinity of a winding core part toward the center part by a method wherein a part, where an element is wound around by a sheet of separator paper only or the separator paper and cathode foil, is provided on the start-of-winding part inside a capacitor take-up element, the element is inserted into an aluminum case, and the open end of the aluminum case is sealed using a sealing material. CONSTITUTION:The center part of the external circumference of the wound material is fixed by a roll-fastening tape 14 consisting of Mylar and polypropylene. Also, the center part of the capacitor take-up section 11 is formed in cavity part 15, and a section, which is formed by winding only a separator paper or separator sheet and cathode foil only, is provided on the start-of- winding part 16 located inside the capacitor take-up element 11, and the presence of cathode foil is not allowed there. The capacitor take-up element 11 is inserted into the aluminum case 1 together with a driving electrolyte, and the open end of the aluminum case 17 is curling-sealed using a hole-sealing material.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an aluminum electrolytic capacitor, and more specifically, to an aluminum electrolytic capacitor for power supplies used in switching power supplies and the like.

Conventional technology Conventional aluminum electrolytic capacitors, as shown in Figure 3,
A dielectric oxide film is formed on the surface of the roughened anode foil, an anode lead terminal 1 is connected to the anode foil, and a cathode lead terminal 2 is connected to the anode foil through a separator paper. Then, the wound material is fixed with a winding tape 3 made of mylar or polypropylene to form a capacitor winding element 4, and this capacitor winding element 4 is used together with a driving electrolyte.
It was constructed by inserting it into a bottomed cylindrical aluminum case (not shown) and sealing the open end of the aluminum case with a sealing material (not shown).

Problems to be Solved by the Invention When abnormal stress such as overvoltage is applied to the above-mentioned conventional aluminum electrolytic capacitor, leakage current increases, and reaction gas with the driving electrolyte due to electrolysis is generated in the capacitor winding element 4. Internal pressure is generated from inside and increases, and a force acts to deform the capacitor winding element 4 inward and outward.

In this case, since the outside is fixed with a winding tape 3 made of Mylar or polypropylene, outward deformation can be prevented.

However, since the center of the winding core of the capacitor winding element 4 is a hollow part 5, when gas is generated from the capacitor winding element 4 and its internal pressure increases, the capacitor winding The area around the winding core of the element 4 could not withstand the internal pressure, and buckling ea and eb occurred in the cavity 6 toward the center as shown in FIG. Such buckling 6! When L, 6b occurs, the anode foil or cathode foil cracks or breaks, and the pieces of foil that occur at this time may break through the separator paper and cause a short circuit. However, if a short circuit occurs in the capacitor winding element 4, the spark will ignite the driving electrolyte, causing the aluminum electrolytic capacitor to catch fire.

The present invention solves these problems, and even if the internal pressure of the capacitor winding element increases during abnormal conditions and buckling occurs near the winding core toward the center, the anode foil and cathode foil The purpose of this invention is to provide an aluminum electrolytic capacitor that does not cause short circuits.

Means for Solving the Problems In order to achieve the above object, the Al ε electrolytic capacitor of the present invention has a capacitor winding element in which an anode foil and a cathode foil are wound together with separator paper and impregnated with a driving electrolyte. Only separator paper is placed at the beginning of the inner winding.
Alternatively, a part is provided in which only separator paper and cathode foil are wound, this capacitor winding element is inserted into an aluminum case, and the open end of the aluminum case is sealed with a sealing material.

Effects According to the above configuration, a portion where only the separator paper or only the separator paper and cathode foil is wound is provided at the beginning of winding inside the capacitor winding element, so that the aluminum electrolytic capacitor is protected from abnormalities such as overvoltage. When stress is applied, gas generation from the capacitor winding element increases, the internal pressure of the capacitor winding element increases, and a force acts to deform the vicinity of the winding core toward the center. Buckling occurs toward the center, and even if this buckling causes cracks in the foil and fragments of the foil, the winding start part inside the capacitor winding element is made up of only separator paper or separator paper. This is a portion in which only the cathode foil is wound, so that short circuits between the anode foil and the cathode foil will not occur.

Embodiment Hereinafter, one embodiment of the present invention will be described based on the accompanying drawings. In FIGS. 1 and 2, 11 is a capacitor winding confectionery, and this capacitor winding element 11 forms a dielectric oxide film on the surface of a roughened anode foil, and connects an anode lead terminal 12. This anode foil is connected to the cathode lead terminal 13 via a separator paper, and is wound together with the roughened cathode foil, and the center of the outer periphery of the wound product is fixed with a winding tape 14 made of mylar or polypropylene. By doing I) configuring. Further, the center of the capacitor winding element 11 is a hollow part 15, and in the inner winding start part 16 of the capacitor winding element 11, only separator paper or only separator paper and cathode foil is wound. A section is provided to prevent the presence of anode foil. 17
is a cylindrical aluminum case with a bottom, and this aluminum case 17
By inserting the capacitor winding element 11 together with the driving electrolyte into the aluminum case 17 and curling the open end of the aluminum case 17 with a sealing material (not shown),
It constitutes an aluminum electrolytic capacitor.

When abnormal stress such as overvoltage is applied to the Al ε electrolytic capacitor having the above configuration, leakage current increases, and reaction gas with the driving electrolyte is generated from inside the capacitor winding element 11 due to electrolysis. The internal pressure increases, and a force acts to deform the capacitor winding element 11 inwardly and outwardly. In this case, since the outer side is fixed with a winding tape 3 made of Mylar or polypropylene, outward deformation can be prevented. Furthermore, due to the increase in the internal pressure of the capacitor winding element 11, a force acts to deform the winding core region toward the center, causing buckling toward the upper middle region. This causes cracks in the foil and fragments of the foil, but the winding start portion 1 inside the capacitor winding element 11
6 is a part where only separator paper or only separator paper and cathode foil are wound, so there is no anode foil, and as a result, the buckling causes cracks in the cathode foil, causing the cathode foil to crack. Even if debris occurs, it will not cause a short circuit.

Effects of the Invention As is clear from the description of the above embodiments, the aluminum electrolytic capacitor of the present invention has a part where only separator paper or only separator paper and cathode foil is wound around the winding start part inside the capacitor winding element. Because of this, when an abnormal stress such as overvoltage is applied to an aluminum electrolytic capacitor, gas generation from the capacitor winding element increases and the internal pressure of the capacitor winding element increases, causing damage to the area around the winding core. The inside of the capacitor winding element acts as a force to deform the capacitor, and buckles toward the center. The beginning of winding is the part where only the separator paper or only the separator paper and negative foil are wound. Therefore, there is no chance of short circuit between the anode foil and the cathode foil, and as a result, there is no risk of fire. It is something that can be obtained without sex.

[Brief explanation of the drawing]

Fig. 1 is a perspective view showing a separated state of the capacitor winding element and the case of an electrolytic capacitor in one embodiment of the present invention; Fig. 2 is a cross-sectional view of the capacitor winding element; The figure is a partially enlarged perspective view of a capacitor winding element in a conventional aluminum electrolytic capacitor. 11... Capacitor winding element, 16...
・・・Start part of winding, 17・・・Aluminum case. Name of agent: Patent attorney Shigetaka Awano and 1 other person 1st
Figure 2 Figure 3

Claims (1)

[Claims] A part where only the separator paper or only the separator paper and the cathode foil is wound around the inner winding start part of the capacitor winding element, which is made by winding an anode foil and a cathode foil together with separator paper and impregnating it with a driving electrolyte. , insert this capacitor winding element into the aluminum case,
An aluminum electrolytic capacitor characterized in that the open end of the aluminum case is sealed with a sealing material.