Disclosed herein is a stacked/folded type electrode assembly configured to have a structure in which two or more unit cells, each of which includes a separator disposed between a positive electrode and a negative electrode, each having an electrode mixture including an electrode active material applied to a current collector, are wound using a sheet type separation film, wherein the positive electrode is configured to have a structure in which a positive electrode mixture is coated on an aluminum foil as the current collector and the negative electrode is configured to have a structure in which a negative electrode mixture is coated on a metal foil, other than the aluminum foil, as the current collector, the unit cells include one or more full-cells and/or bi-cells, one of the unit cells located at each outermost side of the electrode assembly is configured such that one outermost electrode of the unit cell is a single-sided electrode, the single-sided electrode being configured such that the electrode mixture is applied only to one major surface of the current collector facing the separator, and the separation film has higher elongation than the separator.