Hermetically sealed capacitor assembly
A capacitor assembly that includes a conductive polymer electrolytic capacitor that is enclosed and hermetically sealed within a ceramic housing in the presence of an inert gas is provided. Without intending to be limited by theory, the present inventors believe that the ceramic housing is capable of limiting the amount of oxygen and moisture supplied to the conductive polymer of the capacitor. In this manner, the conductive polymer is less likely to oxidize in high temperature environments, thus increasing the thermal stability of the capacitor assembly.
1. A capacitor assembly comprising:
an electrolytic capacitor comprising an anode containing a porous sintered pellet that includes tantalum or niobium oxide, an anode lead wire extending from the anode, a dielectric layer formed over and within the pellet by anodic oxidation, and a cathode overlying the dielectric layer, the cathode including a conductive polymer;
a housing within which the electrolytic capacitor is enclosed, wherein the housing defines an interior cavity having a gaseous atmosphere that contains an inert gas and includes a wall disposed between two opposing sides to define the cavity, wherein the wall exists in a single plane;
a first conductive trace that defines a surface facing the interior cavity of the housing and that is in direct electrical contact with the anode lead wire;
a second conductive trace that defines a surface facing the interior cavity of the housing and that is in electrical contact with the cathode, wherein the wall is in direct contact with the first conductive trace or the second conductive trace;
a cathode termination that is in electrical connection with the second conductive trace and located external to the housing; and
an anode termination that is in electrical connection with the first conductive trace and located external to the housing.
2. The capacitor assembly of claim 1 , wherein the pellet includes tantalum.
3. The capacitor assembly of claim 1 , wherein the pellet includes niobium oxide.
4. The capacitor assembly of claim 1 , wherein the conductive polymer includes poly(3,4-ethylenedioxythiophene) or a derivative thereof.
5. The capacitor assembly of claim 1 , wherein the inert gas includes nitrogen, helium, argon, xenon, neon, krypton, radon, or combinations thereof.
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 inert gases constitute from about 75 wt. % to 100 wt. % of the gaseous atmosphere.
8. The capacitor assembly of claim 1 , wherein oxygen constitutes less than about 1 wt. % of the gaseous atmosphere.
9. The capacitor assembly of claim 1 , wherein an antireflection material is applied to one or more walls of the housing.
10. The capacitor assembly of claim 1 , wherein the electrolytic capacitor has a lower surface that defines a plane beneath which the first conductive trace is located.
11. The capacitor assembly of claim 1 , wherein the housing is hermetically sealed to a lid.
12. The capacitor assembly of claim 1 , wherein a second conductive adhesive is disposed on the surface of the second conductive trace.
13. The capacitor assembly of claim 1 , wherein a first conductive adhesive is disposed on the surface of the first conductive trace.