SOLID ELECTROLYTIC CAPACITOR AND MANUFACTURING METHOD THEREOF

• US 20160099113A1
• Filed: 10/02/2015
• Published: 04/07/2016
• Est. Priority Date: 10/03/2014
• Status: Active Grant

• Current Assignee: Rubycon Corporation
• Original Assignee: Rubycon Corporation
• Inventors: KOMATSU, Akihiko, SAKURAI, Yoshishige, IIJIMA, Akira, SAKAGUCHI, Masayuki, NOZAWA, Yosuke
• Granted Patent: US 9,978,527 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H01G 9/0036 Formation of the solid electrolyte layer
• CPC Class Codes: H01G 9/022 Electrolytes; Absorbents
• CPC Class Codes: H01G 9/025 Solid electrolytes H01G11/54 takes precedence
• CPC Class Codes: H01G 9/151 with wound foil electrodes

Abstract

A solid electrolytic capacitor includes: an anode foil on which an oxide film is formed; a cathode foil; and a separator between the anode and cathode foils, wherein a solid electrolyte in a fine particle form made of a conductive high molecular weight compound and a water-soluble high-molecular weight compound in a liquid form are introduced into a gap between the anode and cathode foils in a state where the water-soluble high-molecular weight compound in a liquid form surrounds the solid electrolyte, and a ratio of an area that the solid electrolyte occupies in the gap is set to a value which falls within a range of 1 vol % to 30 vol %, and a ratio of an area that the water-soluble high-molecular weight compound in a liquid form occupies in the gap is set to a value which falls within a range of 10 vol % to 99 vol %.

Claims

1. A solid electrolytic capacitor comprising:

an anode foil having a surface on which an oxide film is formed;

a cathode foil; and

a separator disposed between the anode foil and the cathode foil, wherein a solid electrolyte in a fine particle form made of a conductive high molecular weight compound and a water-soluble high-molecular weight compound in a liquid form are introduced into a gap formed between the anode foil and the cathode foil in a state where the water-soluble high-molecular weight compound in a liquid form surrounds the solid electrolyte, and a ratio of an area that the solid electrolyte occupies in the gap is set to a value which falls within a range of 1 vol % to 30 vol %, and a ratio of an area that the water-soluble high-molecular weight compound in a liquid form occupies in the gap is set to a value which falls within a range of 10 vol % to 99 vol %.

2. The solid electrolytic capacitor according to claim 1, wherein an average particle size of the solid electrolyte in a fine particle form is set to a value which falls within a range of 1 nm to 300 nm.

3. The solid electrolytic capacitor according to claim 1, wherein the water-soluble high-molecular weight compound in a liquid form has an oxide film repairing property.

4. The solid electrolytic capacitor according to claim 1, wherein the water-soluble high-molecular weight compound in a liquid form is a mixed material made of two or more kinds of water-soluble high-molecular weight compounds having different molecular weights.

5. The solid electrolytic capacitor according to claim 4, wherein out of two or more kinds of water-soluble high-molecular weight compounds having different molecular weights, a molecular weight of the water-soluble high-molecular weight compounds having the largest molecular weight is 1.2 or more times as large as a molecular weight of the water-soluble high-molecular weight compound having the smallest molecular weight.

6. The solid electrolytic capacitor according to claim 4, wherein the ratio of the water-soluble high-molecular weight compound having the largest molecular weight out of two or more kinds of high-molecular weight compounds having different molecular weights with respect to the water-soluble high-molecular weight compound in a liquid form is set to a value which falls within a range of 20 vol % to 80 vol %.

7. The solid electrolytic capacitor according to claim 1, wherein the water-soluble high-molecular weight compound is polyalkylene oxide, water-soluble silicone, branched polyether or derivatives of these materials.

8. The solid electrolytic capacitor according to claim 7, wherein when the water-soluble high-molecular weight compound is a polyalkylene oxide, a molecular weight of the water-soluble high-molecular weight compound is set to a value which falls within a range of 100 to 1000, and when the water-soluble high-molecular weight compound is a water-soluble silicone, branched polyether, a derivative of a polyalkylene oxide, a derivative of a water-soluble silicone, or a derivative of branched polyether, a molecular weight of the water-soluble high-molecular weight compound is set to a value which falls within a range of 200 to 3000.

9. A method of manufacturing a solid electrolytic capacitor comprising:

a first step of preparing a capacitor element which includes an anode foil having a surface on which an oxide film is formed, a cathode foil, and a separator arranged between the anode foil and the cathode foil;

a second step of introducing a solid electrolyte in a fine particle form made of a conductive high-molecular weight compound into a gap formed between the anode foil and the cathode foil such that a ratio of an area that the solid electrolyte occupies in the gap is set to a value which falls within a range of 1 vol % to 30 vol %; and

a third step of introducing a water-soluble high-molecular weight compound in a liquid form in the gap formed between the anode foil and the cathode foil such that the water-soluble high-molecular weight compound surrounds the solid electrolyte and a ratio of an area that the water-soluble high-molecular weight compound in a liquid form occupies in the gap is set to a value which falls within a range of 10 vol % to 99 vol % in this order.

10. The method of manufacturing a solid electrolytic capacitor according to claim 9, wherein an average particle size of solid electrolyte in a fine particle form is set to a value which falls within a range of 1 nm to 300 nm.

11. The method of manufacturing a solid electrolytic capacitor according to claim 9, wherein, in the second step, a solid electrolyte dispersion liquid in which the solid electrolyte is dispersed in a solvent is filled in the gap using a vacuum impregnation method or an immersion impregnation method and, thereafter, the solvent is removed from the gap thus introducing the solid electrolyte into the gap.

12. The method of manufacturing a solid electrolytic capacitor according to claim 9, wherein, in the third step, the water-soluble high-molecular weight compound in a liquid form is introduced into the gap by filling using a vacuum impregnation method or an immersion impregnation method.