Solid electrolytic capacitor with high temperature leakage stability
View Patent ↗A solid electrolytic capacitor and method for forming a solid electrolytic capacitor with high temperature leakage stability is described. The solid electrolytic capacitor has improved leakage current and is especially well suited for high temperature environments such as down-hole applications.
1. A method for forming a solid electrolytic capacitor with high temperature leakage stability comprising:
providing an anode;
forming a dielectric on said anode;
applying a cathode on said dielectric;
applying a transition layer on said cathode wherein said transition layer comprises a blocking layer;
plating a metal layer on said transition; and
electrically connecting a cathode termination to said cathode
wherein said solid electrolytic capacitor has a leakage of no more than 0.10 CV after 500 hrs at temperature of at least 200° C.
2. The method for forming a solid electrolytic capacitor of claim 1 wherein said solid electrolytic capacitor has a leakage of no more than 0.05 CV after 500 hrs at temperature of at least 200° C.
3. The method for forming a solid electrolytic capacitor of claim 2 wherein said solid electrolytic capacitor has a leakage of no more than 0.01 CV after 500 hrs at temperature of at least 200° C.
4. The method for forming a solid electrolytic capacitor of claim 1 wherein said solid electrolytic capacitor has a leakage of no more than 0.10 CV after 500 hrs at temperature of at least 220° C.
5. The method for forming a solid electrolytic capacitor of claim 4 wherein said solid electrolytic capacitor has a leakage of no more than 0.05 CV after 500 hrs at temperature of at least 220° C.
6. The method for forming a solid electrolytic capacitor of claim 5 wherein said solid electrolytic capacitor has a leakage of no more than 0.01 CV after 500 hrs at temperature of at least 220° C.
7. The method for forming a solid electrolytic capacitor of claim 6 wherein said metal layer does not contain silver or sulfur.
8. The method for forming a solid electrolytic capacitor of claim 1 wherein said plating a metal layer comprises plating a layer comprising nickel.
9. The method for forming a solid electrolytic capacitor of claim 8 wherein said plating comprises plating a layer consisting essentially of nickel.
10. The method for forming a solid electrolytic capacitor of claim 1 wherein said cathode comprises MnO 2 .
11. The method for forming a solid electrolytic capacitor of claim 1 wherein said cathode layer has a thermal decomposition temperature of greater than 350° C.
12. The method for forming a solid electrolytic capacitor of claim 11 wherein said thermal decomposition temperature is greater than 500° C.
13. The method for forming a solid electrolytic capacitor of claim 1 wherein the capacitor is encapsulated.
14. The method for forming a solid electrolytic capacitor of claim 13 wherein said capacitor is encapsulated in a material selected from polymer, metal and ceramic.
15. The method for forming a solid electrolytic capacitor of claim 13 wherein said capacitor is encapsulated in a hermetic seal.
16. The method for forming a solid electrolytic capacitor of claim 13 wherein said capacitor is encapsulated in a material which does not form a hermetic seal.
17. The method for forming a solid electrolytic capacitor of claim 1 wherein said blocking layer has a thickness of no more than 2 microns.
18. The method for forming a solid electrolytic capacitor of claim 1 wherein said transition layer does not include a metal filled layer.
19. A solid electrolytic capacitor comprising:
an anode with an anode lead in electrical contact with said anode;
a dielectric on said anode;
a cathode on said dielectric with a cathode lead in electrical contact with said cathode wherein said cathode comprises a conductive layer, a blocking layer and a plated layer comprising nickel; and
wherein said solid electrolytic capacitor has a leakage of 0.10 CV after 500 hrs at temperature of at least 200° C.
20. The solid electrolytic capacitor of claim 19 wherein said solid electrolytic capacitor has a leakage of no more than 0.05 CV after 500 hrs at temperature of at least 200° C.
21. The solid electrolytic capacitor of claim 20 wherein said solid electrolytic capacitor has a leakage of no more than 0.01 CV after 500 hrs at temperature of at least 200° C.
22. The solid electrolytic capacitor of claim 19 wherein said solid electrolytic capacitor has a leakage of no more than 0.10 CV after 500 hrs at temperature of at least 220° C.
23. The solid electrolytic capacitor of claim 22 wherein said solid electrolytic capacitor has a leakage of no more than 0.05 CV after 500 hrs at temperature of at least 220° C.
24. The solid electrolytic capacitor of claim 23 wherein said solid electrolytic capacitor has a leakage of no more than 0.01 CV after 500 hrs at temperature of at least 220° C.
25. The solid electrolytic capacitor of claim 19 wherein said plated layer does not contain silver or sulfur.
26. The solid electrolytic capacitor of claim 25 wherein said plated layer consisting essentially of nickel.
27. The solid electrolytic capacitor of claim 19 wherein said cathode is MnO 2 .
28. The solid electrolytic capacitor of claim 19 wherein said cathode layer has a thermal decomposition temperature of greater than 350° C.
29. The solid electrolytic capacitor of claim 28 wherein said cathode layer has a thermal decomposition temperature of greater than 500° C.
30. The solid electrolytic capacitor of claim 19 wherein the capacitor is encapsulated.
31. The solid electrolytic capacitor of claim 30 wherein said capacitor is encapsulated in a material selected from polymer, metal and ceramic.
32. The solid electrolytic capacitor of claim 30 wherein said capacitor is encapsulated in a hermetic seal.
33. The solid electrolytic capacitor of claim 30 wherein said capacitor is encapsulated in a material which does not form a hermetic seal.
34. The solid electrolytic capacitor of claim 19 wherein said blocking layer has a thickness of less than 2 microns.