CYLINDRICAL LI SECONDARY BATTERY

摘要

Provided is a cylindrical lithium ion secondary battery which is improved in the resistance against an external pressure of a winding spool and is prevented in the shortage of an electrode assembly due to the deformation of a winding spool member. The cylindrical lithium ion secondary battery comprise a jelly-roll type electrode assembly which comprises a first electrode plate, a second electrode plate and a separator interposed between the first electrode plate and the second electrode plate; a winding spool member(700) which is inserted into the winding spool part of the electrode assembly and is provided with a coating formed at the outer side; a case which has a space for accommodating the electrode assembly; and a cap assembly which is combined with the upper part of the case to seal it. Preferably the coating is made of an insulating material.