A lithium ion secondary battery and a jelly-roll type electrode assembly
in a lithium ion secondary battery including a can and a cap assembly
together with the electrode assembly. The electrode assembly is made up
of two electrodes; a ceramic separator coating on at least one surface
among the four surfaces of the two electrode plates and located between
the two opposing electrodes; and porous polymer resin separation films
placed between the electrode plates at certain locations where the plates
are bent to relatively small radii of curvature and outward from an
innermost portion of a core, and/or at terminal ends of the electrode
plates, respectively.