Method of manufacturing electrolytic capacitor

• US 9,373,448 B2
• Filed: 03/07/2012
• Issued: 06/21/2016
• Est. Priority Date: 03/25/2011
• Status: Active Grant

• Current Assignee: Panasonic Intellectual Property Management Co., Ltd. (Panasonic Holdings Corporation)
• Original Assignee: Panasonic Intellectual Property Management Co., Ltd. (Panasonic Holdings Corporation)
• Inventors: Majima, Ryo, Ishimoto, Hitoshi, Aoyama, Tatsuji
• Primary Examiner(s): Cleveland, Michael
• Assistant Examiner(s): Eslami, Tabassom Tadayyon
• Application Number:
  US13/696,343
• Publication Number:
  US 20130059064A1
• Time in Patent Office: 1,567 Days
• Field of Search: 361/503, 361/523, 361/528, 361/502, 361/500, 29/250.3, 257/303, 257/532, 257/259, 427/80, 427/79, 438/239
• US Class Current: 1/1
• CPC Class Codes: H01G 11/48 Conductive polymers
• CPC Class Codes: H01G 11/52 Separators
• CPC Class Codes: H01G 11/56 Solid electrolytes, e.g. gels; Additives therein
• CPC Class Codes: H01G 9/0029 Processes of manufacture
• CPC Class Codes: H01G 9/0036 Formation of the solid electrolyte layer
• CPC Class Codes: H01G 9/028 Organic semiconducting electrolytes, e.g. TCNQ
• CPC Class Codes: Y02E 60/13 Energy storage using capacitors
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries

Abstract

A method of manufacturing an electrolytic capacitor includes preparing a dielectric film formed on a surface of an anode foil, forming a first conductive polymer layer on a surface of the dielectric film by immersing the anode foil in first dispersion solution including conductive polymer particles and forming a second conductive polymer layer covering the first conductive polymer layer solvent by immersing the anode foil in second dispersion solution including second conductive polymer particles and second solvent. The surface of the anode foil has plural pits formed therein. The second dispersion solution has a pH value farther from 7 than the first dispersion solution does. This configuration can suppress damages to the dielectric film.

Claims

1. A method of manufacturing an electrolytic capacitor, said method comprising:

preparing an anode including a dielectric film provided at a surface thereof;

impregnating the anode with a first dispersion solution including first conductive polymer particles and a first solvent; and

after said impregnating the anode with the first dispersion solution, impregnating the anode with a second dispersion solution including second conductive polymer particles and a second solvent,

wherein;

a pH value of the first dispersion solution is closer to 7 than a pH value of the second dispersion solution and is larger than the pH value of the second dispersion solution,

the first dispersion solution and the second dispersion solution are respectively made by adjusting a pH value of a common mother liquid containing conductive polymer particles and a solvent, and

during said impregnating the anode with the first dispersion solution, the first dispersion solution contacts the dielectric film.

2. The method of claim 1, wherein a mode of diameters of the first conductive polymer particles is smaller than a mode of diameters of the second conductive polymer particles.

3. The method of claim 2, wherein the surface of the anode at which the dielectric film is provided has a plurality of pits formed therein, and

wherein a mode of diameters of the second conductive polymer particles is smaller than a mode of diameters of the plurality of the pits.

4. The method of claim 1, wherein a weight concentration of the first conductive polymer particles in the first dispersion solution is lower than a weight concentration of the second conductive polymer particles in the second dispersion solution.

5. The method of claim 1, wherein the first dispersion solution has a lower viscosity than the second dispersion solution.

6. The method of claim 1, wherein the first dispersion solution has a pH value of 6 to 8, and the second dispersion solution has a pH value of 4 to 6.5.

7. The method of claim 1, wherein said impregnating the anode with the first dispersion solution is performed so as to cause formation of a first conductive polymer layer on the dielectric film.

8. The method of claim 7, wherein said impregnating the anode with the second dispersion solution is performed so as to cause formation of a second conductive polymer layer on the first conductive polymer layer.

9. The method of claim 8, wherein a mode of diameters of the first conductive polymer particles is equal to a mode of diameters of the second conductive polymer particles.

10. The method of claim 1, wherein the pH value of the first dispersion solution or the pH value of the second dispersion solution is adjusted by adding a basic substance of a compound to the common mother liquid.

11. The method of claim 1, wherein the pH value of the first dispersion solution or the pH value of the second dispersion solution is adjusted by diluting the common mother liquid.

12. The method of claim 1, wherein the pH value of the first dispersion solution or the pH value of the second dispersion solution is adjusted by removing an anion from the common mother liquid.

13. The method of claim 1, wherein a mode of diameters of the first conductive polymer particles is equal to a mode of diameters of the second conductive polymer particles.