An electrode assembly includes a first sub-unit body including a plurality of stacked first unit bodies, and a second sub-unit body at a lower portion of the first sub-unit body and including a plurality of stacked first unit bodies and a second unit body at a lower portion of the first unit bodies, and each of the first unit bodies includes: first and second electrode plates of a first electrode separately arranged at a side of a first separator; a second separator on the first and second electrode plates of the first electrode; a first electrode plate of a second electrode arranged to correspond to the first electrode plate of the first electrode, with the first separator therebetween; and a second electrode plate of the second electrode arranged to correspond to the second electrode plate of the first electrode, with the second separator therebetween.