The present invention provides an electrode assembly having a structure in which a plurality of electrode plates are stacked with a separator interposed between a cathode plate and an anode plate. Each of the electrode plates comprises: an electrode tab protruding outwardly from one side of each of the electrode plates to form a tab-lead joint portion; and at least two fixing portions, each having a structure protruding outwardly from the one side and/or an other side of each of the electrode plates by a length corresponding to 10-50% of a length of the electrode tab, wherein the fixing portions of the same polarity, positioned vertically parallel to each other, are mutually bonded to maintain a stacking gap between the electrode plates when the electrode plates are stacked.
