A secondary battery comprising: a case; an electrode assembly accommodated in the case, and including a first electrode plate, a second electrode plate, and a separator between the first and second electrode plates (122, 124); a first terminal portion electrically connected to the electrode assembly; and a cap plate configured to cover an opening of the case, wherein the first terminal portion comprises: a first electrode terminal passing through the cap plate to protrude upward from a first position of the cap plate; and a first current collector comprising a first end connected to the first electrode terminal, and a second end connected to the first electrode plate, wherein the first current collector comprises: a first plate connected to the first electrode terminal, and arranged parallel to the cap plate; and a second plate connected to the first electrode plate, and extending away from the first plate in a vertical direction, wherein the second plate has a surface that is in contact with a non-coating portion of the first electrode plate and arranged parallel to the non-coating portion, and is connected to the first electrode plate, and characterized in that the first current collector includes a plurality of notches arranged in the surface of the second plate, each of the plurality of notches extending in a widthwise direction (Y-direction) thereof, wherein the plurality of notches are positioned at intervals along a first edge of the surface of the second plate, and wherein the second plate further includes a second edge parallel to the first edge, and the first edge of the second plate having the plurality of notches is nearer to a center of the electrode assembly as compared to the second edge of the second plate. a case; an electrode assembly accommodated in the case, and including a first electrode plate, a second electrode plate, and a separator between the first and second electrode plates (122, 124); a first terminal portion electrically connected to the electrode assembly; and a cap plate configured to cover an opening of the case, wherein the first terminal portion comprises: a first electrode terminal passing through the cap plate to protrude upward from a first position of the cap plate; and a first current collector comprising a first end connected to the first electrode terminal, and a second end connected to the first electrode plate, a first electrode terminal passing through the cap plate to protrude upward from a first position of the cap plate; and a first current collector comprising a first end connected to the first electrode terminal, and a second end connected to the first electrode plate, wherein the first current collector comprises: a first plate connected to the first electrode terminal, and arranged parallel to the cap plate; and a second plate connected to the first electrode plate, and extending away from the first plate in a vertical direction, wherein the second plate has a surface that is in contact with a non-coating portion of the first electrode plate and arranged parallel to the non-coating portion, and is connected to the first electrode plate, and characterized in that the first current collector includes a plurality of notches arranged in the surface of the second plate, each of the plurality of notches extending in a widthwise direction (Y-direction) thereof, wherein the plurality of notches are positioned at intervals along a first edge of the surface of the second plate, and wherein the second plate further includes a second edge parallel to the first edge, and the first edge of the second plate having the plurality of notches is nearer to a center of the electrode assembly as compared to the second edge of the second plate. a first plate connected to the first electrode terminal, and arranged parallel to the cap plate; and a second plate connected to the first electrode plate, and extending away from the first plate in a vertical direction, wherein the second plate has a surface that is in contact with a non-coating portion of the first electrode plate and arranged parallel to the non-coating portion, and is connected to the first electrode plate, and characterized in that the first current collector includes a plurality of notches arranged in the surface of the second plate, each of the plurality of notches extending in a widthwise direction (Y-direction) thereof, wherein the plurality of notches are positioned at intervals along a first edge of the surface of the second plate, and wherein the second plate further includes a second edge parallel to the first edge, and the first edge of the second plate having the plurality of notches is nearer to a center of the electrode assembly as compared to the second edge of the second plate.