An electrode assembly comprising: a plurality of first electrodes including a first electrode portion including a first active material layer and a first uncoated region electrically connected to the first electrode portion; a separation membrane that receives each first electrode portion, includes a plurality of receiving portions arranged at predetermined intervals, and is curved so that respective surfaces of adjacent receiving portions face each other; and a plurality of second electrodes that are respectively positioned between the receiving portions facing each other to overlap the first electrode portion, and that respectively include a second electrode portion including a second active material layer and a second uncoated region electrically connected to the second electrode portion, wherein the separation membrane includes a first bonding portion that is positioned at an edge of the receiving portion and seals one side of the receiving portion, and the first uncoated region is configured to cross the first bonding portion to protrude outside of the receiving portion, wherein the separation membrane includes a pair of second bonding portions that are respectively connected with opposite ends of the first bonding portion and are respectively formed at an edge of the receiving portion in a direction crossing the first bonding portion, and wherein the second electrode portion includes an extended electrode portion protruding outside of the border line of the first electrode portion, and the extended electrode portion includes at least one notch that is concave toward the border line of the first electrode portion. a plurality of first electrodes including a first electrode portion including a first active material layer and a first uncoated region electrically connected to the first electrode portion; a separation membrane that receives each first electrode portion, includes a plurality of receiving portions arranged at predetermined intervals, and is curved so that respective surfaces of adjacent receiving portions face each other; and a plurality of second electrodes that are respectively positioned between the receiving portions facing each other to overlap the first electrode portion, and that respectively include a second electrode portion including a second active material layer and a second uncoated region electrically connected to the second electrode portion, wherein the separation membrane includes a first bonding portion that is positioned at an edge of the receiving portion and seals one side of the receiving portion, and the first uncoated region is configured to cross the first bonding portion to protrude outside of the receiving portion, wherein the separation membrane includes a pair of second bonding portions that are respectively connected with opposite ends of the first bonding portion and are respectively formed at an edge of the receiving portion in a direction crossing the first bonding portion, and wherein the second electrode portion includes an extended electrode portion protruding outside of the border line of the first electrode portion, and the extended electrode portion includes at least one notch that is concave toward the border line of the first electrode portion.