Electrode assembly having stepped portion, as well as battery cell, battery pack, and device including the electrode assembly

An electrode assembly comprising a stack of unit cells, each of the unit cells comprising at least one negative electrode and at least one positive electrode, alternately stacked in a stacking direction,

• wherein at least one separator is located on each of both sides of the electrodes, and
• at least one of the unit cells has an area different from that of an adjacent one of the unit cells to define a first stepped portion of the electrode assembly,
• the electrode assembly further comprising at least one single electrode having negative or positive polarity, the single electrode disposed along an upper surface or a lower surface of the electrode assembly in the stacking direction, such that the single electrode is adjacent to a first one of the unit cells, and the single electrode having an area different from that of the first unit cell so as to define a second stepped portion of the electrode assembly.