BATTERY PACK CASE, BATTERY PACK, AND BATTERY DEVICE INCLUDING SAME

A battery pack according to various embodiments comprises: a cell assembly including a plurality of battery cells; and a battery pack case that accommodates the cell assembly, wherein the battery pack case includes: a lower frame; and a plurality of side frames extending from the lower frame in a substantially vertical direction, and the plurality of side frames may be configured as a combination of: a first side frame including a first flange and a second flange respectively protruding from the upper portion and the lower portion thereof toward the outside of the battery pack case; and a second side frame having one corner at least partially in contact with the first side frame and including a third flange protruding from the upper portion thereof toward the outside of the battery pack case. Other embodiments are possible.