# US 12,217,917 B2 · Solid electrolytic capacitor with small equivalent series resistance and method for manufacturing the same

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- Number: US 12,217,917 B2
- Document ID: US12217917B2
- Status: Granted
- Kind: B2
- Application number: 18/408,702
- Filed: 2024-01-10
- Published: 2024-05-02
- Granted: 2025-02-04
- Earliest claimed: 2019-06-25
- Assignees: Rubycon Corporation
- Applicants: Rubycon Corporation
- Inventors: Masayuki Sakaguchi; Tetsushi Ogawara; Yoshishige Sakurai; Akira Iijima; Yosuke Nozawa
- Web page: https://patentgrep.com/patent/US12217917B2

## CPC

- H01G 9/035: Liquid electrolytes, e.g. impregnating materials (H01G11/54 takes precedence)
- H01G 9/0036: {Formation of the solid electrolyte layer}
- H01G 9/028: Organic semiconducting electrolytes, e.g. TCNQ
- H01G 9/145: Liquid electrolytic capacitors (H01G11/00 takes precedence)
- H01G 9/151: {with wound foil electrodes}
- H01G: CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-SENSITIVE DEVICES OF THE ELECTROLYTIC TYPE (selection of specified materials as dielectric H01B3/00; capacitors having potential barriers H10D1/62, H10K10/10)

## Abstract

A solid electrolytic capacitor (1) includes an anode foil (2a) having formed thereon an oxide film, a cathode foil (2c), and a separator (2d), and is equipped with a solid electrolyte (20) formed of an electroconductive polymer compound in a fine particle form, and a water-soluble compound solution (30) introduced to surround the solid electrolyte (20), the solid electrolyte (20) contains a polyol compound having a molecular weight of less than 200 and a number of hydroxy groups of 4 or more as a first water-soluble compound (2f1), the water-soluble compound solution (30) contains one kind or multiple kinds of a glycol compound in a liquid form as a second water-soluble compound (2f2), and the second water-soluble compound (2f2) has an average molecular weight of less than 400.

## Claims

### Claim 1

A solid electrolytic capacitor comprising:
an anode foil having formed thereon an oxide film,
a cathode foil, and
a separator disposed between the anode foil and the cathode foil, and
being equipped with
a solid electrolyte formed of an electroconductive polymer compound in a fine particle form, and
a water-soluble compound solution introduced to surround the solid electrolyte,
the solid electrolyte contains diglycerin as a first water-soluble compound,
the water-soluble compound solution containing one kind or multiple kinds of polyethylene glycol, diethylene glycol or ethylene glycol as a glycol compound in a liquid form as a second water-soluble compound,
the second water-soluble compound having an average molecular weight of less than 400, and
the water-soluble compound solution contains water in an amount of 0.5 wt % or more.

### Claim 2 (depends on 1)

The solid electrolytic capacitor according to claim 1, wherein the average molecular weight of the second water-soluble compound is 106 or more and 300 or less.

### Claim 3 (depends on 1)

The solid electrolytic capacitor according to claim 1, wherein the solid electrolyte contains diglycerin as the first water-soluble compound in an amount of 80 wt % or more.

### Claim 4 (depends on 1)

The solid electrolytic capacitor according to claim 1, wherein the water-soluble compound solution has a configuration in which no ionic compound is contained.

### Claim 5

A method for manufacturing a solid electrolytic capacitor having a configuration including an anode foil having formed thereon an oxide film, a cathode foil, a separator disposed between the anode foil and the cathode foil, and a solid electrolyte, the method comprising:
forming the solid electrolyte in a gap between the anode foil and the cathode foil with a dispersing liquid containing an electroconductive polymer compound in a fine particle form and diglycerin as a first water-soluble compound, and
then introducing a water-soluble compound solution containing one kind or multiple kinds of polyethylene glycol, diethylene glycol or ethylene glycol as a glycol compound in a liquid form as a second water-soluble compound to surround the formed solid electrolyte,
the second water-soluble compound having an average molecular weight of less than 400, and
the water-soluble compound solution contains water in an amount of 0.5 wt % or more.

### Claim 6 (depends on 5)

The method of claim 5, wherein the average molecular weight of the second water-soluble compound is 106 or more and 300 or less.