JPS605053B2 - Electrolytic capacitor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electrolytic paper for an electrolytic capacitor, and provides an electrolytic capacitor having an electrolytic paper pre-containing phosphoric acids.

Generally, it is well known that adding phosphoric acids to the electrolytic solution of an electrolytic capacitor improves chemical conversion properties or breakdown voltage.

For example, 1975 Patent No. 867, for which the present applicant previously applied for a patent for an electrolyte containing phosphoric acids.
No. 69 (Hakama Kaisho No. 52-10557) ``Electrolytic solution for driving electrolytic capacitors''. By the way, as shown in FIG. 1, a first electrolytic paper 2, an anode foil 3, and a second electrolytic paper 4 are laminated in order on a cathode foil 1 in such an electrolytic solution, and these are wound. The capacitor element is impregnated.

However, in traditional impregnation methods, phosphoric acids are exposed to the natural fibers of electrolytic paper, such as kraft paper or Manila hemp paper.
Phosphates may not be evenly distributed within the capacitor element, and may not be present in effective amounts, particularly in the center of the capacitor element. However, the present invention eliminates the above-mentioned drawbacks by:
The present invention provides an electrolytic capacitor having electrolytic paper containing phosphoric acids in advance.

In the present invention, there are various methods for pre-containing phosphoric acids in electrolytic paper, and typical examples are listed below.

'a- A method in which the liquid for making electrolytic paper contains the required amount of phosphoric acid, and the liquid is used to make paper.

'b - A method of immersing the electrolytic paper in a solution containing the required amount of phosphoric acids after making the electrolytic paper, or a method of spraying this solution onto the electrolytic paper. [c'[a}
A combination of and [b}.

As the phosphoric acids, orthophosphoric acid, phosphorous acid, or their salts are effective, and the amount contained in the electrolytic paper is 0.0% by weight.
03-2. Adversary M% is preferred.

Next, the capacitor element, which is interposed between the anode foil and the cathode foil, is impregnated with electrolytic paper containing phosphoric acids in another electrolytic solution, but at this time, phosphoric acids are further added to the electrolytic solution. We can also expect a synergistic effect. Furthermore, the electrolyte phosphate ion concentration in the electrolytic capacitor is 0.
01 to 1.15 wt% is preferable. Next, Table 1 shows a comparison of the breakdown voltage failure rate during aging and the initial characteristics of the following example and the example according to the present invention. The electrolyte is rated at 160V and 470F. Table 1 From Table 1, the electrolytic capacitor according to the present invention can reduce the breakdown voltage failure rate to about 1/10 and the leakage current to about 2/3 compared to the conventional example. The effect can be fully demonstrated.

In addition, Fig. 2 shows the state of distribution of phosphate ions when a conventional electrolytic capacitor and an electrolytic capacitor according to the present invention are disassembled.As shown by the curved line, the electrolytic capacitor according to the present invention has a lower curve. Compared to the conventional electrolytic capacitor shown in No. 1, the distribution of phosphate ions is almost uniform from the upper end to the lower end of the capacitor element 5, which proves that the effect of phosphoric acids is fully exerted in each part of the capacitor element 5.

[Brief explanation of the drawing]

Figure 1 shows the laminated state of the anode foil, cathode foil, and electrolytic paper of a capacitor element, and Figure 2 shows the distribution of phosphate ions. In the figure, 1 is a cathode foil, 2 and 4 are electrolytic papers, 3 is an anode foil, and 5 is a capacitor element. Figure 1 Figure 2

Claims (1)

[Scope of Claims] 1. An electrolytic capacitor in which electrolytic paper is interposed between an anode foil and a cathode foil, in which a required amount of phosphoric acid is pre-contained in the electrolytic paper. 2 In claim 1, the amount of phosphoric acids in the electrolytic paper is 0.03 to 2.0 wt% in terms of weight ratio in the electrolytic paper.
An electrolytic capacitor. 3 In claim 1, the phosphoric acid is orthophosphoric acid,
Electrolytic capacitors that are phosphorous acids or their salts. 4 In claim 1, the electrolytic solution phosphate ion concentration in the electrolytic capacitor is 0.01 to 1.15 wt.
% electrolytic capacitor.