CELL STACK ASSEMBLY AND BATTERY PACK INCLUDING THE SAME

A cell stack assembly and a battery pack includes the same, the cell stack assembly including a cell stack having a plurality of battery cells stacked with electrode leads derived from one or both sides; and a separating member configured to contact a first side surface of at least one battery cell of the cell stack. The separating member including a hollow part therein and a protrusion part on each of both side surfaces.