Disclosed herein is a battery cell configured to have a structure in which an electrode stack, which is configured to have a structure in which positive electrodes and negative electrodes are stacked in the height direction on the basis of the ground in the state in which separators are disposed respectively between the positive electrodes and the negative electrodes, is mounted in a battery case in a sealed state, the battery case is formed in a pipe shape having a hollow part, and the electrode stack is formed in a shape corresponding to the shape of the battery case.