The present invention relates to a battery pack having pouch-type battery cells from which gas therein can be released when same has expanded due to the gas pressure therein rising above the reference pressure, the battery pack according to a preferred embodiment of the present invention comprising: a plurality of pouch-type battery cells; a case having barriers for suppressing width-wise expansion of the pouch-type battery cells, and for accommodating same in each partitioned space created by the barriers; and a perforated unit disposed on the case and having pin members, the same number as the number of pouch-type battery cells, for piercing the area not supported by the barrier from among the surfaces of the pouch-type battery cells.