Abstract: A battery pack includes a pair of battery modules having a plurality of first partition walls formed to extend downward from a lower surface thereof, a supporting plate having a plurality of second partition walls formed to extend upward from an upper surface thereof and a gas discharge hole formed at a longitudinal center thereof, the supporting plate being coupled to a bottom of the pair of battery modules such that plurality of first partition walls and the plurality of second partition walls are adjacent and overlap each other in one-to-one pairs and a BMS assembly coupled to an upper portion of the pair of battery modules in a plug-in type.