Compact multilayer ceramic-to-metal seal structure

DETAILED DESCRIPTION A compact bipolar battery cell of the present invention includes an extremely thin metal-ceramic-metal seal which is used to electrically insulate the battery's anode current collector from its cathode current collector.
Additionally, the seal is used to establish a hermetic seal that prevents leakage of the battery's electrolyte from between the anode and the cathode.
The seal itself is made from layers of powders which are sintered together into a monolithic structure.
In accordance with the present invention, adjacent layers in the seal have different proportions of metallic and ceramic constituents.
Specifically, the seal includes a first metallic surface layer which is attachable to the anode current collector and a second metallic surface layer which is attachable to the cathode current collector.
These surface layers essentially include only metallic constituents.
On the other hand, at the center of the seal between the first surface layer and the second surface layer, is a ceramic core layer which essentially includes only dielectric constituents.
Between this ceramic core layer and each of the surface layers is a transitional zone that includes a plurality of transitional segments having various proportions of metallic constituents and metallic oxide constituents.
As implied above, each transitional zone of intermixed metallic and ceramic (i.
e.
metallic oxides or other insulating compounds or glasses) constituents establishes a proportionally tapered concentration of the constituents across the transitional zone.
Preferably, each of the transitional zones will have three or more segments.
For purposes of initial discussion, only three segments will be considered.
These segments are designated as first, second and third transitional segments.
In an alternate embodiment, the possibility for five such segments is considered.
For the three segment transitional zone embodiment of the present invention, the first transitional segment is adjacent the ceramic core layer and has approximately seventy five percent (75%) ceramic or metallic oxide constituents and twenty five percent (25%) metallic constituents