Lithium rechargeable batteries having functional center pins are provided. A lithium rechargeable battery has a center pin whose top and bottom ends are blocked by a thermal cut-off composition to reduce the void volume inside a bare cell during initial overcharge. The thermal cut-off composition melts at a temperature within a specific temperature range, e.g. between about 80 and about 250 DEG C. This prevents the battery from exploding and igniting. Thus, the inventive lithium rechargeable batteries have improved thermal stability.