Patent ID: 8658303

Claim:
A middle or large-sized battery pack case in which a battery module having a plurality of stacked battery cells or unit modules (‘unit cells’), which can be charged and discharged, is mounted, wherein the battery pack case is provided at an upper part and a lower part thereof with a coolant inlet port and a coolant outlet port, respectively, which are directed in opposite directions so that a coolant for cooling the unit cells can flow from one side to the other side of the battery module in a direction perpendicular to a stacking direction of the unit cells, the battery pack case is further provided with a flow space (‘a coolant introduction part’) extending from the coolant inlet port to the battery module and another flow space (‘a coolant discharge part’) extending from the battery module to the coolant outlet port, an upper end inside of the coolant introduction part facing a top of a unit cell stack is configured to have an inclined plane inclined from an end opposite to the coolant inlet port toward the coolant inlet port at a positive (+) angle (A) to the top of the unit cell stack, the coolant inlet port is inclined at an angle (B) greater than the inclination angle (A) of the inclined plane so as to correspond to an internal structure of a device in which the middle or large-sized battery pack case, comprising the battery module, is mounted, the inclination angle (A) of the inclined plane is 3 to 8 degrees and the inclination angle (B) of the coolant inlet port is 20 to 80 degrees, the end opposite to the coolant inlet port is spaced apart from the top of the battery cell stack by a height equivalent to 10% or less of a height of the unit cell stack, and a transition from inclination angle (A) to inclination angle (B) is located at an intermediate portion of the battery module.