Solid electrolytic capacitor for use under high temperature and humidity conditions

Patent metadata

Field	Value
Publication number	US-9236193-B2
Application number	US-201314044290-A
Country	US
Kind code	B2
Filing date	Oct 2, 2013
Priority date	Oct 2, 2013
Publication date	Jan 12, 2016
Grant date	Jan 12, 2016

Abstract

A solid electrolytic capacitor that is capable of exhibiting good electrical properties even under the extreme conditions of high temperature and humidity levels is provided. More particularly, the capacitor contains a capacitor element that includes a sintered porous anode body, a dielectric that overlies the anode body, and a solid electrolyte that overlies the dielectric. The solid electrolyte contains a conductive polymer and an organometallic coupling agent. The capacitor also contains a moisture barrier layer that overlies the solid electrolyte and is formed from a hydrophobic elastomer that has a low surface energy such that it is not readily wettable by an aqueous medium.

First claim

What is claimed is:

1. A solid electrolytic capacitor comprising:
a capacitor element that includes a sintered porous anode body, a dielectric that overlies the anode body, a solid electrolyte that overlies the dielectric, and a moisture barrier layer that overlies the solid electrolyte, wherein the solid electrolyte includes a conductive polymer and an organometallic coupling agent that contains an organic chain with at least one reactive group bonded to a metal atom, and further wherein the moisture barrier layer includes a hydrophobic elastomer, wherein the hydrophobic elastomer is a silicone elastomer, wherein the silicone elastomer is formed from a polydimethylsiloxane, polymethylhydrogensiloxane, dimethyidiphenylpolysiloxane, dimethyl/methylphenylpolysiloxane, polymethylphenylsiloxane, methylphenyl/dimethylsiloxane, vinyldimethyl terminated polydimethylsiloxane, vinylmethyl/dimethylpolysiloxane, vinyldimethyl terminated vinylmethyl/dimethylpolysiloxane, divinylmethyl terminated polydimethylsiloxane, vinylphenylmethyl terminated polydimethylsiloxane, dimethylhydro terminated polydimethylsiloxane, methylhydro/dimethylpolysiloxane, methylhydro terminated methyloctylpolysiloxane, methylhydro/phenylmethyl polysiloxane, fluoro-modified polysiloxane, or a combination thereof;
an anode termination that is in electrical connection with the anode body;
a cathode termination that is in electrical connection with the solid electrolyte; and
a resinous casing that encapsulates the capacitor element and leaves exposed at least a portion of the anode termination and the cathode termination.

2. The solid electrolytic capacitor of claim 1 , wherein the organometallic coupling agent is an organosilane.

3. The solid electrolytic capacitor of claim 1 , wherein the solid electrolyte contains a layer that includes the organometallic coupling agent and the conductive polymer.

4. The solid electrolytic capacitor of claim 1 , wherein the solid electrolyte contains a layer that includes the organometallic coupling agent and another layer that includes the conductive polymer.

5. The solid electrolytic capacitor of claim 1 , wherein the hydrophobic elastomer has a contact angle with water of about 90° or more, as determined in accordance with ASTM D7490-08.

6. The solid electrolytic capacitor of claim 1 , wherein the hydrophobic elastomer has a water vapor transmission rate of about 150 grams per square meter per 24 hours or less, as determined in accordance with ASTM F-1249.

7. The solid electrolytic capacitor of claim 1 , wherein the hydrophobic elastomer has a Young's modulus of about 5,000 kilopascals or less, determined at a temperature of about 25° C.

8. The solid electrolytic capacitor of claim 1 , wherein the hydrophobic elastomer has a tensile strength of from about 1 to about 5,000 kilopascals, determined at a temperature of about 25° C.

9. The solid electrolytic capacitor of claim 1 , wherein the anode body includes tantalum and the dielectric includes tantalum pentoxide.

10. The solid electrolytic capacitor of claim 1 , wherein the conductive polymer is chemically polymerized.

11. The solid electrolytic capacitor of claim 1 , wherein the conductive polymer is a substituted polythiophene.

12. The solid electrolytic capacitor of claim 11 , wherein the substituted polythiophene is poly(3,4-ethylenedioxythiophene).

13. The solid electrolytic capacitor of claim 1 , wherein a cathode coating overlies the solid electrolyte, the cathode coating containing a carbonaceous layer and silver layer.

14. The solid electrolytic capacitor of claim 1 , wherein an anode lead extends from the anode body and is connected to the anode termination.

15. A solid electrolytic capacitor comprising:
a capacitor element that includes a sintered porous anode body, a dielectric that overlies the anode body, a solid electrolyte that overlies the dielectric, and a moisture barrier layer that overlies the solid electrolyte, wherein the solid electrolyte includes a conductive polymer and an organometallic coupling agent that contains an organic chain with at least one reactive group bonded to a metal atom, and further wherein the moisture barrier layer includes a hydrophobic elastomer, wherein the moisture barrier layer contains a non-conductive filler, wherein the non-conductive filler is silica, wherein the silica contains (CH 3 ) n —Si— groups, wherein n is an integer of 1 to 3;
an anode termination that is in electrical connection with the anode body;
a cathode termination that is in electrical connection with the solid electrolyte; and
a resinous casing that encapsulates the capacitor element and leaves exposed at least a portion of the anode termination and the cathode termination.

16. The solid electrolytic capacitor of claim 15 , wherein the organometallic coupling agent is an organosilane.

17. The solid electrolytic capacitor of claim 15 , wherein the solid electrolyte contains a layer that includes the organometallic coupling agent and the conductive polymer.

18. The solid electrolytic capacitor of claim 15 , wherein the solid electrolyte contains a layer that includes the organometallic coupling agent and another layer that includes the conductive polymer.

19. The solid electrolytic capacitor of claim 15 , wherein the hydrophobic elastomer has a contact angle with water of about 90° or more, as determined in accordance with ASTM D7490-08.

20. The solid electrolytic capacitor of claim 15 , wherein the hydrophobic elastomer has a water vapor transmission rate of about 150 grams per square meter per 24 hours or less, as determined in accordance with ASTM F-1249.

21. The solid electrolytic capacitor of claim 15 , wherein the hydrophobic elastomer has a Young's modulus of about 5,000 kilopascals or less, determined at a temperature of about 25° C.

22. The solid electrolytic capacitor of claim 15 , wherein the hydrophobic elastomer has a tensile strength of from about 1 to about 5,000 kilopascals, determined at a temperature of about 25° C.

23. The solid electrolytic capacitor of claim 15 , wherein the anode body includes tantalum and the dielectric includes tantalum pentoxide.

24. The solid electrolytic capacitor of claim 15 , wherein the conductive polymer is chemically polymerized.

25. The solid electrolytic capacitor of claim 15 , wherein the conductive polymer is a substituted polythiophene.

26. The solid electrolytic capacitor of claim 25 , wherein the substituted polythiophene is poly(3,4-ethylenedioxythiophene).

27. The solid electrolytic capacitor of claim 15 , wherein a cathode coating overlies the solid electrolyte, the cathode coating containing a carbonaceous layer and silver layer.

28. The solid electrolytic capacitor of claim 15 , wherein an anode lead extends from the anode body and is connected to the anode termination.

Assignees

• Avx Corp

Inventors

• Tatsuno Jyunya
• Aoki Kiyofumi

Classifications

• H01G9/0003 Primary

  Protection against electric or thermal overload; cooling arrangements; means for avoiding the formation of cathode films (H01G9/12 takes precedence) · CPC title

• H01G9/10 Primary

  Sealing, e.g. of lead-in wires · CPC title

• H01G9/15

  Solid electrolytic capacitors (H01G11/00 takes precedence) · CPC title

• H01G9/028

  Organic semiconducting electrolytes, e.g. TCNQ · CPC title