| 摘要 |
Provided is a secondary battery in which gas is discharged smoothly by allowing the welded part of a cap plate and a can to tear in case of swelling, thereby reducing the time and cost required for the formation of a vent. A secondary battery comprises a jelly-roll type electrode assembly which comprises two different electrodes and a separator interposed between the two electrodes; a can(11) in which the electrode assembly is accommodated; and a cap assembly which is provided with a cap plate(110) combined with the upper part of the can by welding, and the some part of the welded part of the cap plate and the surrounding part are thinner that the other part. Preferably a groove(115) is formed on at least one surface of the surrounding part of the cap plate. |
