BATTERY PACK COOLING SYSTEM

A battery pack cooling system includes a plurality of cells disposed in an internal space of a battery pack case so as to form a cooling passage configured to cool the cell modules by cooling air flowing in the cooling passage. The cooling passage includes a cooling air inlet passage, a cooling air exhaust passage, and a plurality of cooling branch passages disposed to connect the cooling air inlet passage and the cooling air exhaust passage in parallel. A minimum temperature sensor is disposed in the upstream position to measure a lowest temperature region in a first cell module. A maximum temperature sensor is disposed in the downstream position which becomes a highest temperature region in the first cell module. Another temperature sensor is disposed in a second cell module to measure the temperature of either the highest temperature or the lowest temperature in the second cell module.