NOVELTY - A battery assembly (34) comprises: a casing (36) comprising a casing wall having inner and outer surfaces and an opening through it; a sleeve (38) comprising a compressible material; a battery cell inserted into the sleeve; and a sealing member coupled to the casing.    USE - The battery assembly is useful for automotive and for electronic devices.    ADVANTAGE - The battery assembly has high performance and optimized battery performance.    DETAILED DESCRIPTION - A battery assembly comprises: a casing comprising a casing wall having inner and outer surfaces and an opening through it and being shaped such that a coolant chamber is formed within the casing adjacent to the opening; a sleeve comprising a compressible material inserted through the opening, the sleeve being shaped such that a sealing portion is positioned over the outer surface of the casing wall; a battery cell inserted into the sleeve such that at least a portion of the battery cell is positioned within the coolant chamber; and a sealing member coupled to the casing such that the sealing member applies a force onto the sealing portion of the sleeve causing the sealing portion of the sleeve to at least partially compress and seal the coolant chamber. An INDEPENDENT CLAIM is an automotive battery assembly comprising; a casing comprising a casing wall being shaped such that a coolant chamber is formed within the casing and having inner and outer surfaces, a set of slots though it adjacent to the coolant chamber, and first and second coolant ports in fluid communication with the coolant chamber; a set of sleeves, each comprising a compressible rubber material and being inserted through a respective one of the slots, the sleeves being shaped such that a sealing portion of each sleeve is positioned over the outer surface of the casing wall and the sealing portion of at least some of the sleeves is adjacent to the sealing portion of another sleeve; a set of battery cells, each battery cell being inserted into a respective one of the sleeves such that at least a lower portion is positioned within the coolant chamber and an upper portion extends out of the coolant chamber, each of the battery cells comprising first and second terminals coupled to the upper portion; and at least one sealing member coupled to the casing such that a force is applied onto the sealing portion of each of the set of sleeves causing the sealing portion of each of the sleeves to at least partially compress and seal the coolant chamber.    DESCRIPTION OF DRAWING(S) - The drawing shows an exploded isometric view of a battery assembly.    Battery assembly (34)    Casing (36)    Battery cell sleeves (38)    Battery cells (40)    Lid (42)    Top piece (54)    Bottom piece (56)    Side pieces (58)    Battery cell slots (60)    Port (62)    Sealing portion (66)    Terminals (74, 76)    Opening (78)    Fasteners (80)