Seal ring and associated method

1. An energy storage device, comprising:

a first electrode;

a second electrode;

a case;

a cap;

a seal ring for sealing the energy storage device located in a region formed by the first electrode, the second electrode, the case, and the cap,

wherein the seal ring comprises a weldable first portion and a weldable second portion that are electrically isolatable from each other by an electrically insulating third portion comprising alumina disposed therebetween,

wherein the weldable first portion is in a direct contact with the first electrode of the energy storage device and the weldable second portion is in a direct contact with the second electrode of the energy storage device,

wherein at least one of the weldable first portion and the weldable second portion comprises a cermet, and wherein the weldable first portion is welded to an inner surface of a housing of the energy storage device and the weldable second portion is welded to a cap of the energy storage device.

2. The energy storage device as defined in claim 1 , wherein the cermet comprises a ceramic material selected from a group consisting of alumina, silica, yttria, and ytterbia.

3. The energy storage device as defined in claim 1 , wherein the cermet comprises at least one refractory metal.

4. The energy storage device as defined in claim 3 , wherein the refractory metal comprises one or more of molybdenum, rhenium, tantalum, or tungsten.

5. The energy storage device as defined in claim 3 , wherein at least one of the weldable first portion and the weldable second portion comprises at least one of nickel, iron, or chromium.

6. The energy storage device as defined in claim 3 , wherein an amount of the refractory metal in the cermet material is in a range of from about 5 volume percent to about 50 volume percent.

7. The energy storage device as defined in claim 3 , wherein an amount of the refractory metal in the cermet material is in a range of from about 51 volume percent to about 100 volume percent.

8. The energy storage device as defined in claim 1 , wherein the electrically insulating third portion comprises alumina having a dielectric strength of more than 9 at 1 megahertz.

9. The energy storage device as defined in claim 1 , further comprising:

a double prime beta alumina separator placed inside a volume of the housing to create an anode compartment and a cathode compartment;

wherein the seal ring further comprises a fourth portion of an alumina-based material having coefficient of thermal expansion that is within 10 percent of the coefficient of thermal expansion of double prime beta alumina separator.

10. The energy storage device as defined in claim 9 , further including the double prime beta alumina separator and wherein the fourth portion of the seal ring is secured to the double prime beta alumina separator, and the weldable first portion, the weldable second portion, the electrically insulating third portion and the fourth portion within the seal ring are oriented or located relative to each other to minimize thermal stresses during operation and heating of the seal ring.

11. The energy storage device as defined in claim 1 , further comprising a housing weld structure disposed between the first weldable portion and the housing, and a cap weld structure disposed between the second weldable portion and the cap.

12. The energy storage device as defined in claim 1 , wherein the first electrode is an anode and the second electrode is a cathode, with a separator disposed therebetween.

13. The energy storage device as defined in claim 1 , wherein the seal ring forms a hermetic weld structure.

14. The energy storage device as defined in claim 1 , wherein a metal content of the weldable first portion and weldable second portion are different.