Manganese oxide capacitor for use in extreme environments
A capacitor assembly for use in high voltage and high temperature environments is provided. More particularly, the capacitor assembly includes a capacitor element containing an anodically oxidized porous, sintered body that is coated with a manganese oxide solid electrolyte. To help facilitate the use of the capacitor assembly in high voltage (e.g., above about 35 volts) and high temperature (e.g., above about 175° C.) applications, the capacitor element is enclosed and hermetically sealed within a housing in the presence of a gaseous atmosphere that contains an inert gas.
1. A capacitor assembly comprising:
a capacitor element comprising an anode formed from an anodically oxidized, sintered porous body and a solid electrolyte coating the anode, wherein the solid electrolyte comprises a manganese oxide;
a housing that defines an interior cavity within which the capacitor element is positioned, wherein the interior cavity has a gaseous atmosphere that contains an inert gas;
a polymeric restraint that is in contact with a surface of the capacitor element, wherein at least about 5% of the interior cavity of the housing remains unoccupied by the capacitor element and the polymeric restraint;
an anode termination that is in electrical connection with the anode body; and
a cathode termination that is in electrical connection with the solid electrolyte.
2. The capacitor assembly of claim 1 , wherein the porous body is formed from tantalum or niobium oxide powder.
3. The capacitor assembly of claim 2 , wherein the powder has a specific charge of less than about 70,000 μF*V/g.
4. The capacitor assembly of claim 1 , wherein the manganese oxide is in the form of a film that coats at least a portion of the dielectric in a substantially uniform manner.
5. The capacitor assembly of claim 1 , wherein the capacitor element occupies about 30 vol. % or more of the interior cavity.
6. The capacitor assembly of claim 1 , wherein inert gases constitute from about 50 wt. % to 100 wt. % of the gaseous atmosphere.
7. The capacitor assembly of claim 1 , wherein the housing is formed from a metal, plastic, ceramic, or a combination thereof.
8. The capacitor assembly of claim 1 , further comprising a lead that extends in a lateral direction from the porous body of the anode, wherein the lead is positioned within the interior cavity of the housing.
9. The capacitor assembly of claim 8 , further comprising a connective member that contains a first portion that is positioned generally perpendicular to the lateral direction of the anode lead and connected thereto.
10. The capacitor assembly of claim 9 , wherein the connective member further contains a second portion that is generally parallel to the lateral direction in which the anode lead extends.
11. The capacitor assembly of claim 10 , wherein the second portion is positioned within the housing.
12. The capacitor assembly of claim 1 , wherein the manganese oxide is formed from a pyrolytically converted manganese oxide precursor solution containing a dispersant.