A battery cooling system comprising: a main frame for defining a structure of a battery rack; a space dividing frame for dividing the inside of the main frame into a plurality of levels; a battery module located inside the main frame and supported by the space dividing frame; a pair of refrigerant guide plates respectively installed at the upper and lower ends of the battery module and installed to be inclined in the same direction with predetermined angles with respect to the upper and lower surfaces thereof; and side panels coupled to the sides of the main frame and having channel slits formed in at least a part thereof, wherein the battery module includes: a first battery module loaded in a first level among the plurality of levels; and a second battery module loaded in a second level adjacent to the first level and located under the same, wherein the refrigerant guide plates include: a first refrigerant guide plate provided in the upper portion of the first battery module; a second refrigerant guide plate provided in the lower portion of the first battery module; a third refrigerant guide plate provided in the upper portion of the second battery module; and a fourth refrigerant guide plate provided in the lower portion of the second battery module, wherein the channel slits are respectively formed at one side and the other side of the side panels in a width direction, and wherein the channel slit formed at one side of the side panel in a width direction serves as a passage for introducing air from the outside of the battery rack into the inside thereof, and the air is discharged out of the battery rack through the channel slit formed at the other side of the side panel in a width direction. a main frame for defining a structure of a battery rack; a space dividing frame for dividing the inside of the main frame into a plurality of levels; a battery module located inside the main frame and supported by the space dividing frame; a pair of refrigerant guide plates respectively installed at the upper and lower ends of the battery module and installed to be inclined in the same direction with predetermined angles with respect to the upper and lower surfaces thereof; and side panels coupled to the sides of the main frame and having channel slits formed in at least a part thereof, wherein the battery module includes: a first battery module loaded in a first level among the plurality of levels; and a second battery module loaded in a second level adjacent to the first level and located under the same, a first battery module loaded in a first level among the plurality of levels; and a second battery module loaded in a second level adjacent to the first level and located under the same, wherein the refrigerant guide plates include: a first refrigerant guide plate provided in the upper portion of the first battery module; a second refrigerant guide plate provided in the lower portion of the first battery module; a third refrigerant guide plate provided in the upper portion of the second battery module; and a fourth refrigerant guide plate provided in the lower portion of the second battery module, wherein the channel slits are respectively formed at one side and the other side of the side panels in a width direction, and wherein the channel slit formed at one side of the side panel in a width direction serves as a passage for introducing air from the outside of the battery rack into the inside thereof, and the air is discharged out of the battery rack through the channel slit formed at the other side of the side panel in a width direction. a first refrigerant guide plate provided in the upper portion of the first battery module; a second refrigerant guide plate provided in the lower portion of the first battery module; a third refrigerant guide plate provided in the upper portion of the second battery module; and a fourth refrigerant guide plate provided in the lower portion of the second battery module, wherein the channel slits are respectively formed at one side and the other side of the side panels in a width direction, and wherein the channel slit formed at one side of the side panel in a width direction serves as a passage for introducing air from the outside of the battery rack into the inside thereof, and the air is discharged out of the battery rack through the channel slit formed at the other side of the side panel in a width direction.