JPS6316615A - Manufacture of electrolytic capacitor - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] (a) Industrial application field The present invention relates to a method for manufacturing electrolytic capacitors, in particular φ2
The present invention relates to a method of manufacturing an electrolytic capacitor suitable for two or more large electrolytic capacitors.

iol Conventional Technology In recent years, 105°C guarantees have become common even for large electrolytic capacitors, and more difficult problems have arisen than with the 85°C guarantees up until now.

One of the problems is deformation due to bending of the case and terminal board due to gas generation. The gas generated may be, for example, hydrogen gas produced by decomposition of water. As disclosed in Japanese Patent Publication No. 53-42110, it is known to absorb this hydrogen gas by adding dinitrophenol or the like to the electrolytic solution. (c) Invention or problem to be solved However, adding dinitrophenol to the electrolyte is not sufficient to prevent deformation.

This is because in a high temperature state such as 105° C., the aluminum electrode and water react, the gas photogenicity increases, and the hydrogen gas absorption effect of dinitrophenol is exerted (λ disappears).

Conventionally, the existence of moisture in capacitors has been known for a long time, and the presence of moisture in the separator paper of capacitor elements in addition to the electrolyte is understandable because the separator paper has good hygroscopicity, but 85 At temperatures below ℃, the influence of moisture contained in separator 1 could be ignored.

Even with electrolytic capacitors that were guaranteed to have no problems at 85°C, at a high temperature of 105°C, the case and terminal board could become bent, resulting in electrolyte leakage and damage to the case.

B) Means for Solving the Problems The present invention constitutes a capacitor element by arranging an anode electrode foil and a cathode electrode foil to face each other and winding them with a separator paper interposed between them, and the moisture in the separator paper is removed from the capacitor element. The capacitor element is characterized by being impregnated with an electrolytic solution after drying the capacitor element so that the electrolytic solution becomes 0.5% or more and 2.0% or less based on the weight.

(E) Effect By drying the capacitor element to reduce the moisture in the element, the generation of hydrogen gas is suppressed, and deformation of the case and terminal board, as well as the resulting electrolyte leakage and damage, can be eliminated. . However, if the drying process is performed until the water is completely removed, the impregnating electrolyte loses its affinity with the separator paper, and the tan δ of the capacitor increases significantly.

(F) Example Hereinafter, an example of the present invention will be described with reference to the drawings. (
1) is an anode electrode foil made of band-shaped aluminum metal,
The surface of this anode electrode foil (1) is etched, and a dielectric oxide film is formed on the bottom surface. Furthermore, a lead terminal (2) for external extraction is connected to this positive fi electrode foil (1). (3) is a cathode electrode foil, the surface of which is subjected to etching treatment as required, and a dielectric oxide film is formed on this surface.

A lead terminal (21) is connected to this cathode electrode foil (3) in the same way as the anode electrode foil (1).

The anode electrode foil (1) and the cathode electrode foil (3) are placed opposite each other, and a strip of separator paper (4) such as kraft paper or Manila hemp paper is interposed between the anode and cathode electrode foils (31). Turn to form a capacitor element (6).

This capacitor element (6) is dried and becomes a separator! The moisture content in (4) is controlled to be 0.5% or more and 2.0% or less.

In this way, the capacitor element (6) that has been dried is sufficiently impregnated with electrolyte, and stored in the bottomed cylindrical storage case (7), and the terminal plate (8) is attached to the open end of the case (7). Put it on,
Connect the lead terminal (2+ (2+) and external terminal (91), and curl the open end of the case (7) to seal it to obtain an electrolytic capacitor.

Table 1 shows four types of capacitor elements (B) to (E) that were subjected to extensive drying treatment and capacitor elements (A) and (FXG) for comparison as typical examples of the present invention.

Table 1 Note that the capacitor element (6) has a rating of 400V, 220μ
F, and kraft paper was used as the separator paper (4). Table 2 shows the capacitor elements (6
) is impregnated with an electrolytic solution, housed in a case (7), and sealed with a terminal plate (8) as shown in Figure 2.The aluminum electrolytic capacitor is subjected to a high temperature load by applying a rated voltage in a high temperature atmosphere of 105°C. The results of the test are shown.

The electrolytic solution is a high-temperature electrolytic solution in which a boric acid solute is dissolved in a mixed solvent of ethylene glycol and diethylene glycol.

Table 2: Rated voltage applied at 105° C. Here, LC indicates the leakage current after 30 seconds, and C indicates the rate of change of valley 2.

From Table 2, for the conventional capacitor (A), 105'C
In a high temperature load test of 1000 hours, the top of the case swelled, the case was damaged, and the electrolyte leaked from there. In addition, the capacitor characteristics may also be affected by this.
This led to a so-called dry-up condition in which δ suddenly increased and capacity was no longer available.

In contrast, the present Examples (B) to (E) and the Comparative Example (
F) In the case of (G), no deformation of the case etc. was observed even after a high temperature load test of 1000 hours at 105°C.

By the way, comparative examples (F) and (G) in which the moisture content of the separator paper was 0.5% or less were used to dry the capacitor elements.
), the initial state tan δ increases. Therefore, t@n
In order to avoid deformation such as blistering of the case without affecting δ, the moisture content of the separator paper was kept at the normal state (8
, 0-13%), it is necessary to adjust it to 0.5-2.0%.

In this example, the element was dried at high temperature, but the element may be dried using a desiccant or the like.

(G) Effects of the Invention The present invention drying the element before impregnation under appropriate conditions so that the moisture content, which is the ratio of the moisture of the separator paper to its ff1ffi, becomes 0.5% to 2.0%. By controlling the
There is no electrolyte leakage or damage associated with this, and the ta
An electrolytic capacitor without an increase in nδ can be obtained.

[Brief explanation of drawings]

1 and 2 show an electrolytic capacitor to which the present invention is applied, FIG. 1 being a partially developed perspective view showing a cord structure, and FIG. 2 being a sectional view of the electrolytic capacitor. (1)... Anode electrode foil, (31... Cathode electrode foil, (
41... Separator paper, (6)... Capacitor system element, (7)... Case, (8)... Terminal board. Figure 1 Figure 2

Claims (1)

[Claims] (1) Construct a capacitor element by placing an anode electrode foil and a cathode electrode foil facing each other and winding them with a separator paper interposed between them, and the water content of the separator paper is 0.5% or more based on the weight of the separator paper.2. 1. A method for manufacturing an electrolytic capacitor, characterized in that the capacitor element is subjected to a drying treatment so that the electrolyte becomes 0% or less, and then the capacitor element is impregnated with an electrolytic solution.