| 摘要 |
Provided is a cylindrical lithium ion secondary battery which is enhanced in the stability to an external pressure by dispersing the external pressure to many directions and by preventing the deformation of an electrode assembly. The cylindrical lithium ion secondary battery comprise an 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, is wound in vortex and has a certain space at center of winding; a winding spool member(600) which has a pipe shape having a cut groove(630) along a longitudinal direction, is divided into a main body part and left and right parts by two symmetrical first bent parts and is inserted into the center space of the electrode assembly; 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. The extended ling of the external side of the main body part forms an imaginary circumference, and the left and right parts are located inside the circumference. |
