| 摘要 |
PURPOSE: Provided is a lithium secondary battery excellent in performance and safety, which contains an electrode group formed by winding a cathode, a first thin separator, an anode, and a second thick separator. CONSTITUTION: The lithium secondary battery contains the jelly-roll type electrode group formed by winding the cathode(3), the first separator(5), the anode(7), and the second separator(9) in order, wherein the first separator(5) has a thickness of 8-15 micrometer and the second separator(9) has a thickness of 16-25 micrometer and the thickness ratio of the first separator(5) and the second separator(9) is 1:1.5-1:2. |
