Wet electrolytic capacitor containing a plurality of thin powder-formed anodes

• US 20080232030A1
• Filed: 03/20/2007
• Published: 09/25/2008
• Est. Priority Date: 03/20/2007
• Status: Active Grant

• Current Assignee: Kyocera AVX Components Corporation (Kyocera Corporation)
• Original Assignee: AVX Corporation (Kyocera Corporation)
• Inventors: Rawal, Bharat, Ning, Gang, Jones, Brady
• Granted Patent: US 7,649,730 B2
• Time in Patent Office: Days
• US Class Current: 361/503
• CPC Class Codes: H01G 9/008 Terminals
• CPC Class Codes: H01G 9/052 Sintered electrodes
• CPC Class Codes: H01G 9/0525 Powder therefor
• CPC Class Codes: H01G 9/14 Structural combinations or circuits for modifying, or compensating for, electric characteristics of electrolytic capacitors
• CPC Class Codes: H01G 9/145 Liquid electrolytic capacitors H01G11/00 takes precedence

Abstract

A wet electrolytic capacitor that includes a plurality of anodes, cathode, and working electrolyte that is disposed in electrical contact with the anodes and current collector is provided. Any number of anodes may generally be employed, such as from 2 to 40, in some embodiments from 3 to 30, and in some embodiments, from 4 to 20. The anodes are thin and typically have a thickness of about 1500 micrometers or less, in some embodiments about 1000 micrometers or less, and in some embodiments, from about 50 to about 500 micrometers. By employing a plurality of anodes that are relatively thin in nature, the resulting wet electrolytic capacitor is able to achieve excellent electrical properties. For example, the equivalent series resistance (“ESR”)—the extent that the capacitor acts like a resistor when charging and discharging in an electronic circuit—may be less than about 1500 milliohms, in some embodiments less than about 1000 milliohms, and in some embodiments, less than about 500 milliohms, measured with a 2-volt bias and 1-volt signal at a frequency of 1000 Hz.

Claims

1. A wet electrolytic capacitor comprising:

a plurality of anodes having a thickness of about 1500 micrometers or less, the anodes being formed form from a powder;

a cathode;

a working electrolyte disposed in electrical contact with the cathode and the anodes;

an anode termination that is electrically connected to the anodes; and

a cathode termination that is electrically connected to the cathode.

2. The wet electrolytic capacitor of claim 1, wherein the capacitor contains from 2 to 40 anodes.

3. The wet electrolytic capacitor of claim 1, wherein the capacitor contains from 3 to 30 anodes.

4. The wet electrolytic capacitor of claim 1, wherein the anodes have a thickness of about 50 to about 500 micrometers.

5. The wet electrolytic capacitor of claim 1, wherein the anodes include tantalum.

6. The wet electrolytic capacitor of claim 1, wherein the anodes include niobium oxide.

7. The wet electrolytic capacitor of claim 1, wherein the anodes are formed by chemically reducing the powder.

8. The wet electrolytic capacitor of claim 7, wherein the powder includes niobium pentoxide.

9. The wet electrolytic capacitor of claim 1, wherein an anode lead extends from the anodes, the anode lead being connected to the anode termination.

10. The wet electrolytic capacitor of claim 1, wherein a cathode lead extends from the cathode, the cathode lead being connected to the cathode termination.

11. The wet electrolytic capacitor of claim 1, wherein the anodes contain a dielectric layer.

12. The wet electrolytic capacitor of claim 1, wherein the capacitor contains a plurality of cathodes, wherein at least one of the anodes is positioned between at least two cathodes.

13. The wet electrolytic capacitor of claim 12, wherein the capacitor contains from 3 to 40 anodes.

14. The wet electrolytic capacitor of claim 12, wherein the anodes and cathodes are vertically aligned.

15. The wet electrolytic capacitor of claim 12, wherein the anodes and cathodes are horizontally aligned.

16. The wet electrolytic capacitor of claim 1, further comprising a separator that is positioned between the cathode and at least one of the anodes, the separator permitting flow of the working electrolyte.

17. The wet electrolytic capacitor of claim 1, wherein the cathode, the anodes, and the working electrolyte are enclosed within a container.

18. The wet electrolytic capacitor of claim 17, wherein the container includes a lid through which the anode termination and the cathode termination extend.

19. The wet electrolytic capacitor of claim 1, wherein the cathode contains a current collector and a coating of electrochemically-active particles.

20. The wet electrolytic capacitor of claim 1, wherein the working electrolyte is an aqueous solution.

21. The wet electrolytic capacitor of claim 1, wherein the capacitor exhibits an equivalent series resistance of about 1500 milliohms or less, measured with a 2-volt bias and 1-volt signal at a frequency of 1000 Hz.

22. The wet electrolytic capacitor of claim 1, wherein the capacitor exhibits an equivalent series resistance of about 500 milliohms or less, measured with a 2-volt bias and 1-volt signal at a frequency of 1000 Hz.