Patent ID: 8652681

Claim:
A secondary battery, comprising: an electrode assembly; a can receiving the electrode assembly wherein the can includes a wall of a first thickness; and an insulation case having a body that defines a periphery provided at an upper part of the electrode assembly inside the can wherein the insulation case includes at least one projection that extends outward from the periphery of the body towards the wall of the can, wherein a first stepped part is formed on an inner surface of an upper part of the can that has a thickness less than the first thickness wherein the insulation case is positioned in the first stepped part so that the at least one projection engages with the first stepped part; further comprising a cap plate combined to the upper part of the can, where a second stepped part thinner than the first stepped part is formed at an upper part of the stepped part and the cap plate is seated on the second stepped part, and wherein the insulation case comprises a flat main body and at least one projection formed around the main body.