Secondary battery

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, the first electrode plate comprising a non-coating portion at a first end of the electrode assembly, the first end being opposite a second end of the electrode assembly in a lengthwise direction;
• 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 in a first direction 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, the first current collector including a plurality of notches in a first edge of the first current collector, the first edge being at a first side of the first current collector facing toward the second end of the electrode assembly, notches of the plurality of notches being spaced apart from one another in the first direction with a portion of the first current collector that is between the notches being in contact with the first electrode plate, wherein each of the notches extends in the lengthwise direction from the first edge to a base of the notch such that a depth in the lengthwise direction from the first edge to the base of the notch is less than a thickness in the lengthwise direction from the first edge to a second edge of the first current collector that is opposite the first edge in the lengthwise direction,
• 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 second direction opposite the first direction,
• wherein a wide surface of the second plate is in contact with the non-coating portion of the first electrode plate and arranged parallel to the non-coating portion, and is connected to the first electrode plate,
• wherein the plurality of notches is in the wide surface of the second plate in a widthwise direction thereof,
• wherein the first edge is a first edge of the wide surface of the second plate, and wherein the notches of the plurality of notches are at intervals along the first edge,
• wherein the second edge is a second edge of the wide surface of the second plate, and wherein the first edge of the second plate having the plurality of notches is nearer to the second end of the electrode assembly as compared to the second edge.