BOX BODY ASSEMBLY, CASING, BATTERY PACK AND VEHICLE

A box body assembly, and a casing, a battery pack and a vehicle that use the box body assembly are provided. The box body assembly includes a flow channel plate and a cover plate. A flow channel groove is formed in the flow channel plate, the cover plate is fastened to the flow channel plate to cover the flow channel groove and define a heat exchange flow channel for circulation of a heat exchange medium, and the cover plate is configured to be defined by at least one of a box body and a box cover.