摘要 |
Disclosed is a secondary battery having a structure in which a jelly-roll having a cathode/separator/anode structure is mounted in a cylindrical battery case, wherein a plate-shaped insulator mounted on top of the jelly-roll includes a perforated inlet enabling gas discharge and penetration of electrode terminals, a plurality of fine pores having a size that allows permeation of an electrolyte solution, but does not allow permeation of foreign materials, and a plurality of strip or bead shaped protrusions disposed in transverse and/or longitudinal directions on one or both surfaces of the insulator. |