Abstract: A secondary battery in which the structure of an insulating case arranged between an electrode assembly and a cap assembly prevents electrode tabs from being bent. The secondary battery includes: an electrode assembly including a positive electrode, a negative electrode, a separator interposed between the positive electrode and the negative electrode, and electrode tabs respectively extending from the positive electrode and the negative electrode; a can for accommodating the electrode assembly; a cap assembly attached to an opening of the can and connected to the electrode tabs; and an insulating case arranged between the electrode assembly and the cap assembly and including a hole through which one of the electrode tabs pass, the insulating case including barrier ribs respectively extending from at least portions of side walls of the hole.

Abstract: Disclosed is a secondary battery having a element for compensating for and preventing volumetric expansion during charging/discharging of the battery, in order to prevent the electrode assembly from deforming due to rising internal pressure and compensate for and prevent the expansion of the secondary battery case. The secondary battery includes an electrode assembly having positive and negative electrode plates having active materials formed on at least one surface of positive and negative electrode collectors and a separator interposed between the positive and negative electrode plates, a case having a space for containing the electrode assembly and at least one element for compensating for and preventing volumetric expansion, and a cap assembly adapted to be coupled to the case and seal it and provided with a terminal portion in electrical connection to the electrode assembly.