Battery thermal system with interlocking structure components

1. A battery module comprising:

a plurality of battery cells;

a plurality of cooling fin assemblies, each cooling fin assembly positioned between two battery cells, the cooling fin assemblies comprising:

a foot having a top, a bottom opposite the top, and interlocking profiles along opposite ends of the foot, the top of the foot having a pair of slots defined therein;

a pair of cooling fins inserted into the pair of slots in the top of the foot;

wherein the foot of the cooling fin assembly is a separate piece from the pair of cooling fins of the cooling fin assembly and is attached to the cooling fin assembly by the insertion of the pair of cooling fins into the pair of slots in the top of the foot;

wherein the plurality of cooling fin assemblies are stacked such that the interlocking profile on the foot of one cooling fin assembly interlocks with the interlocking profile on the foot of an adjacent cooling fin assembly to form interlocked feet, and such that the bottoms of the interlocked feet of the one cooling fin assembly and the adjacent cooling fin assembly together form an interface surface; and

a heat sink in thermal contact with the interface surface of the interlocked feet.

2. The battery module of claim 1 , further comprising a layer of thermal interface material between the interface surface of the interlocked feet and the heat sink.

3. The battery module of claim 1 , wherein the cooling fin assemblies further comprise an expansion unit between the pair of cooling fins.

4. The battery module of claim 1 , wherein the expansion unit is a layer of foam or a leaf spring.

5. The battery module of claim 1 , wherein the interlocking profiles are tongue and groove profiles.

6. The battery module of claim 1 , wherein the foot is made of aluminum.

7. The battery module of claim 1 , wherein the interface surface of the interlocked feet is flat.

8. A battery module comprising:

a plurality of battery cells;

a plurality of cooling fin assemblies, each cooling fin assembly positioned between two battery cells, the cooling fin assemblies comprising a pair of cooling fins and a foot on at least one side of the cooling fin assemblies, the foot being a separate piece from the pair of cooling fins, the foot having a top, a flat bottom opposite the top, and tongue and groove profiles along opposite ends of the foot, the cooling fin assemblies being stacked such that the tongue and groove profiles on adjacent feet of the cooling fin assemblies interlock the feet, and such that the flat bottoms on the adjacent feet of the cooling fin assemblies together form a flat interface surface;

wherein the foot of each cooling fin assemblies has a pair of slots on the top of the foot, and the pair of cooling fins is positioned in the pair of slots; and

a heat sink in thermal contact with the flat interface surface of the interlocked feet.

9. The battery module of claim 8 , further comprising a layer of thermal interface material between the flat interface surface of the interlocked feet and the heat sink.

10. The battery module of claim 8 , wherein the cooling fin assemblies further comprise an expansion unit between the pair of cooling fins.

11. The battery module of claim 10 , wherein the expansion unit is a layer of foam or a leaf spring.

12. The battery module of claim 8 , wherein the feet of the cooling fin assemblies are made of aluminum.

13. The battery module of claim 8 , wherein the tongue and groove profiles along opposite ends of the foot of the cooling fin assemblies comprise a tongue profile on one end of the foot and a groove profile on an opposite end of the foot.

14. The battery module of claim 13 , wherein:

the tongue profile of the foot projects from the one end of the foot and is received by a groove profile of one adjacent foot; and

the groove profile of the foot receives a tongue profile that projects from another adjacent foot.