Patent ID: 7939196

Claim:
A cylindrical lithium rechargeable battery, comprising: a winding type electrode assembly comprising a first electrode plate, a second electrode plate, and a separator between the first electrode plate and the second electrode plate; a core member arranged in a central space of the electrode assembly and comprising a cut arranged along a longitudinal direction thereof and a short circuit preventing part; a case comprising a space for accommodating the electrode assembly; and a cap assembly combined with an upper portion of the case to hermetically seal the case, wherein the short circuit preventing part comprises first edges disposed at an upper portion of the core member based on the cut and second edges disposed at a bottom portion of the core member based on the cut, wherein the first edges and the second edges are directed in an inward direction of the core member to have a tapered shape, wherein a first portion of the cut is not directed in an inward direction of the core member, and wherein the cut has a first width at the first portion, the short circuit preventing part has a second width, and the first width is less than the second width.