Electrochemical cells including a conductive matrix

1. An electrochemical cell, comprising:

a housing having an interior surface defining a volume;

an elongated separator disposed in the housing volume and defining an axis of the cell, the separator having an inner surface and an outer surface, the inner surface of the separator defining a first compartment, the outer surface of the separator and the interior surface of the housing defining a second compartment having a volume; and

a conductive matrix disposed in at least a portion of the second compartment volume such that the conductive matrix occupies a gap between the outer surface of the separator and the interior surface of the housing, wherein the gap extends in a direction substantially perpendicular to the axis of the electrochemical cell, and wherein the conductive matrix is in direct contact with the interior surface of the housing in a continuous manner around an entire periphery of the separator.

2. The electrochemical cell of claim 1 , wherein the second compartment is further defined by a length substantially parallel to the axis of the cell, and the portion of the second compartment volume occupied by the conductive matrix extends to at least about 50 percent of the length.

3. The electrochemical cell of claim 2 , wherein the portion of the second compartment volume occupied by the conductive matrix extends to from about 60 percent to about 100 percent of the length.

4. The electrochemical cell of claim 1 , wherein the conductive matrix comprises a thermally and electrically conductive material.

5. The electrochemical cell of claim 1 , wherein the conductive matrix has a porosity of at least about 20 percent.

6. The electrochemical cell of claim 5 , wherein the porosity of the conductive matrix is in a range from about 50 percent to about 80 percent.

7. The electrochemical cell of claim 1 , wherein the conductive matrix is in the form of foam, wool, fibers, wires, particles, particle agglomerates, or combinations thereof.

8. The electrochemical cell of claim 1 , wherein the conductive matrix comprises a metallic wool.

9. The electrochemical cell of claim 1 , wherein a width of the gap is in a range from about 1 millimeter to about 10 millimeters, and the width of the gap is completely occupied by the conductive matrix.

10. The electrochemical cell of claim 1 , wherein the separator has at least one concave section and at least one convex section, the concave and convex sections are facing the interior surface of the housing.

11. The electrochemical cell of claim 10 , wherein a width of the gap varies along the outer surface of the separator.

12. The electrochemical cell of claim 1 , wherein the conductive matrix is disposed in the portion of the second compartment volume such that conductive matrix is further in direct contact with the outer surface of the separator in a substantially continuous manner around the entire periphery of the separator.

13. The electrochemical cell of claim 1 , further comprising a conductive thin sheet disposed in the second compartment, wherein the conductive thin sheet substantially conforms to a shape defined by the outer surface of the separator such that a channel is formed between the conductive thin sheet and the outer surface of the separator.

14. The electrochemical cell of claim 13 , wherein the channel has a dimension less than about 0.5 millimeter.

15. The electrochemical cell of claim 13 , wherein the conductive thin sheet is a metal foil.

16. The electrochemical cell of claim 13 , wherein the conductive matrix is disposed in the portion of the second compartment volume such that the conductive matrix is further in direct contact with an outer surface of the conductive thin sheet in a substantially continuous manner around the entire periphery of the separator.

17. The electrochemical cell of claim 1 , wherein the conductive matrix fills from about 10 percent to about 80 percent volume of the second compartment volume.

18. The electrochemical cell of claim 1 , further comprising an anode material disposed in the second compartment volume, wherein the anode material comprises an alkali metal selected from the group consisting of lithium, sodium, and potassium.

19. The electrochemical cell of claim 1 , wherein the first compartment comprises a cathode material comprising an alkali metal halide.

20. An electrochemical cell, comprising:

a housing having an interior surface defining a volume;

an elongated separator disposed in the volume, defining an axis of the cell, the separator having an inner surface and an outer surface; the inner surface defining a first compartment comprising a cathode material; and the outer surface of the separator and the interior surface of the housing defining a second compartment having a volume,

a conductive thin sheet disposed in the second compartment, wherein the conductive thin sheet substantially conforms to a shape defined by the outer surface of the separator such that a channel is formed between the conductive thin sheet and the outer surface of the separator; and

a conductive matrix disposed in a portion of the second compartment volume such that the conductive matrix occupies a gap between an outer surface of the conductive thin sheet and the interior surface of the housing, wherein the gap extends in a direction substantially perpendicular to the axis of the electrochemical cell, and the conductive matrix is in direct contact with both the outer surface of the conductive thin sheet and the interior surface of the housing in a substantially continuous manner around an entire periphery of the separator.