Electrolytic Solution for Electrolytic Capacitor, and Electrolytic Capacitor Using the Same

• US 20080316679A1
• Filed: 09/06/2005
• Published: 12/25/2008
• Est. Priority Date: 09/07/2004
• Status: Active Grant

• Current Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Original Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Inventors: Matsuura, Hiroyuki, Taguchi, Shinya, Sugihara, Yukiyasu, Furusawa, Shigetaka, Hamada, Keiko, Kusayanagi, Hiroki
• Granted Patent: US 7,859,828 B2
• Time in Patent Office: Days
• US Class Current: 361/504
• CPC Class Codes: H01G 9/035 Liquid electrolytes, e.g. impregnating materials H01G11/54 takes precedence
• CPC Class Codes: H01G 9/145 Liquid electrolytic capacitors H01G11/00 takes precedence

Abstract

It is provided the electrolytic solution for use in the electrolytic capacitor including a capacitor element and a casing containing said capacitor element, said capacitor element including a pair of electrodes, and a conductive separator (E) which is formed with a conductive polymer layer (F) containing a dopant agent (H) on its surface and is interposed between said pair of electrodes, said conductive separator (E) and said pair of electrodes being rolled up in an overlapped state with each other, and spaces between said pair of electrodes being impregnated with the electrolytic solution for electrolytic capacitor, wherein an acid component (D) and a base component (C) as electrolytic components to be contained in said electrolytic solution are at such a molar ratio that the acid component (D) is excessive. By use of said electrolytic solution for electrolytic capacitor, the increase in the ESR with the elapse of time in an electrolytic capacitor is suppressed.

Claims

1. An electrolytic solution for use in an electrolytic capacitor comprising a capacitor element and a casing containing said capacitor element, said capacitor element including a pair of electrodes, and a conductive separator (E) which is formed with a conductive polymer layer (F) containing a dopant agent (H) on its surface and is interposed between said pair of electrodes, said conductive separator (E) and said pair of electrodes being rolled up in an overlapped state with each other, and spaces between said pair of electrodes being impregnated with the electrolytic solution for electrolytic capacitor,

wherein an acid component (D) and a base component (C) as electrolytic components to be contained in said electrolytic solution for electrolytic capacitor are at such a molar ratio that said acid component (D) is excessive.

2. An electrolytic solution for electrolytic capacitor according to claim 1, wherein said electrolytic solution contains an antioxidant.

3. An electrolytic solution for electrolytic capacitor according to claim 1, wherein said acid component (D) is organic carboxylic acid (D1).

4. An electrolytic solution for electrolytic capacitor according to claim 3, wherein said organic carboxylic acid (D1) is any one selected from the group consisting of phthalic acid, trimellitic acid, pyromellitic acid, maleic acid, salicylic acid, benzoic acid, and resorcylic acid.

5. An electrolytic solution for electrolytic capacitor according to claim 1, wherein said electrolytic solution for electrolytic capacitor contains a compound (C1) having alkyl-substituted amidine groups as said base component (C).

6. An electrolytic solution for electrolytic capacitor according to claim 1, wherein pH is 2 to 7.

7. An electrolytic capacitor comprising a capacitor element and a casing containing said capacitor element, said capacitor element including a pair of electrodes, a conductive separator (E) which is formed with a conductive polymer layer (F) containing a dopant agent (H) on its surface and is interposed between said pair of electrodes, said conductive separator (E) and said pair of electrodes being rolled up in an overlapped state with each other, and spaces between said pair of electrodes being impregnated with the electrolytic solution for electrolytic capacitor,

wherein said electrolytic solution for electrolytic capacitor is the electrolytic solution for electrolytic capacitor according to claim 1.

8. An electrolytic solution for electrolytic capacitor comprising a capacitor element and a casing containing said capacitor element, said capacitor element including a pair of electrodes composed of an anode chemical foil and a cathode foil, and a p-type doping conductive separator (E′

) which is formed with a p-type doping conductive polymer layer (F′

) containing a p-type dopant agent (H′

) on its surface and is interposed between said pair of electrodes, said p-type doping conductive separator (E′

) and said pair of electrodes being rolled up in an overlapped state with each other, and spaces between said pair of electrodes being impregnated with the electrolytic solution for electrolytic capacitor,

wherein said electrolytic solution for electrolytic capacitor contains a component (A0) having reduction potential of −

1.6 to 0V when measured in the following measuring method;

a method for measuring the reduction potential;

into γ

-butyrolactone into which tetraethylammonium fluoroborate is dissolved at 0.23 mol/L as a supporting electrolyte, a component (A0) is dissolved at 0.1 mol/L, and the potential thereof is measured at the time when the current at −

0.2 μ

A flowed by means of the convective cyclic voltammetry measuring method using a Grassi carbon electrode (φ

1.0 mm) as an active electrode, a (Ag/Ag⁺) electrode as a reference electrode, and a platinum electrode as a counter electrode.

9. An electrolytic solution for electrolytic capacitor according to claim 8, wherein said component (A0) is at least one selected from the group consisting of organic peroxide, primary to tertiary ammonium compounds, trivalent or more polycarboxylic acid compounds, nitro compounds, and benzoquinone compounds.

10. An electrolytic solution for electrolytic capacitor according to claim 8, wherein said electrolytic solution for electrolytic capacitor contains a compound (C′

1) having alkyl-substituted amidine groups and/or a compound (C′

2) having alkyl-substituted guanidine groups.

11. An electrolytic solution for electrolytic capacitor according to claim 8, wherein pH is 2 to 7.

12. An electrolytic capacitor comprising a capacitor element and a casing containing said capacitor element, said capacitor element including a pair of electrodes composed of an anode chemical foil and a cathode foil, and a p-type doping conductive separator (E′

) which is formed with a p-type doping conductive polymer layer (F′

) containing a p-type dopant agent (H′

) on its surface and is interposed between said pair of electrodes, said p-type doping conductive separator (E′

) and said pair of electrodes being rolled up in an overlapped state with each other, and spaces between said pair of electrodes being impregnated with the electrolytic solution for electrolytic capacitor,

wherein said electrolytic solution for electrolytic capacitor is the electrolytic solution for electrolytic capacitor according to claim 8.