Hermetically sealed capacitor assembly
A capacitor assembly that includes an electrolytic capacitor that contains an anode body, dielectric overlying the anode, and a solid electrolyte overlying the dielectric is provided. An anode lead is also electrically connected to the anode body and extends therefrom, The capacitor and leadframe are enclosed and hermetically sealed within a ceramic housing in the presence of an inert gas. In this manner, the solid electrolyte (e.g., conductive polymer) is less likely to undergo a reaction in high temperature environments, thus increasing the thermal stability of the capacitor assembly.
1. A capacitor assembly comprising:
an electrolytic capacitor comprising an anode body that includes tantalum or niobium oxide, dielectric, and solid electrolyte overlying the dielectric, the solid electrolyte including a polypyrrole, polythiophene, polyaniline, polyacetylene, poly-p-phenylene, polyphenolate, or a combination thereof, wherein an anode lead is electrically connected to the anode body and extends therefrom;
a housing within which the electrolytic capacitor is positioned and hermetically sealed, the housing defining an interior cavity having a gaseous atmosphere, the gaseous atmosphere containing an inert gas;
an anode termination that is in electrical connection with the anode lead; and
a cathode termination that is in electrical connection with the solid electrolyte.
2. The capacitor assembly of claim 1 , wherein the conductive polymer is poly(3,4-ethylenedioxythiophene).
3. The capacitor assembly of claim 1 , wherein inert gases constitute from about 75 wt. % to 100 wt. % of the gaseous atmosphere.
4. The capacitor assembly of claim 1 , further comprising a leadframe that contains a first portion that is connected to the anode lead and positioned within the housing.
5. The capacitor assembly of claim 1 , wherein a first region of the anode termination is positioned within the housing and a second region of the anode termination is positioned external to the housing.
6. The capacitor assembly of claim 1 , wherein a first region of the cathode termination is positioned within the housing and a second region of the cathode termination is positioned external to the housing.
7. The capacitor assembly of claim 1 , further comprising a lid that is welded or soldered to the housing.
8. The capacitor assembly of claim 1 , wherein the valve metal composition includes tantalum.
9. The capacitor assembly of claim 1 , wherein the inert gas includes nitrogen, helium, argon, xenon, neon, krypton, radon, or combinations thereof.
10. The capacitor assembly of claim 1 , wherein oxygen constitutes less than about 1 wt. % of the gaseous atmosphere.
11. The capacitor assembly of claim 1 , wherein a conductive adhesive electrically connects the solid electrolyte to the cathode termination.