LIQUID COOLING SYSTEM, BATTERY CASING AND BATTERY PACK

A liquid cooling system includes: a liquid cooling plate (11), a support plate (12) and a water inlet and outlet joint (13). The support plate (12) includes a first through hole (121) and a second through hole (122), and is used for fixedly connecting with the outer wall of the casing body of the battery pack (001). The water inlet and outlet joint (13) is arranged on the support plate (12). One end of the water inlet joint (131) used for connecting with the water inlet port of the liquid cooling plate (11) passes through the first through hole (121) and is connected with the water inlet port. One end of the water outlet joint (132) used for connecting with the water outlet port of the liquid cooling plate (11) passes through the second through hole (122) and is connected with the water outlet port.