A battery charging system includes a battery pack having a plurality of battery cells and a pack terminal, a passage that accommodates a circulation therethrough of a temperature conditioning fluid for the battery pack, the passage includes an inflow part through which the temperature conditioning fluid is introduced and an outflow part through which the temperature conditioning fluid is discharged, an inner control unit that measures a state of the battery pack to supply an inner fluid to the passage, and an outer charging unit that charges the battery pack and that supplies an outer fluid to the passage.