BATTERY PACK CASE WITH NON-UNIFORM THICKNESS

The present invention relates to a battery pack case configured to receive a battery cell stack constituted by a plurality of stacked battery cells therein, the battery pack case including a first case configured to allow the battery cell stack to be mounted therein and a second case coupled to the first case, the second case being configured to cover the battery cell stack, wherein the first case includes a first flat panel portion and a first side portion, the second case includes a second flat panel portion and a second side portion, the thickness of the second flat panel portion of the second case is less than the thickness of the second side portion of the second case, and the first side portion is disposed so as to face a swelling surface of each of the battery cells, whereby it is possible to minimize change in volume of the battery pack case, and therefore it is possible to secure dimensional stability thereof.