US Patent 7666552 Lithium secondary battery and separator therefor

A lithium secondary battery includes an electrode assembly where a negative plate and a positive plate are rolled in the form of a spiral while interposing a separator with a modulus of elasticity of around 2.0 kgf/mm2 or less in the longitudinal direction. A can, inside of which the electrode assembly is mounted together with an electrolyte, is electrically connected to one of the negative plate and the positive plate of the electrode assembly. A cap assembly is fitted to the top of the can, and is electrically connected to the other of the positive plate and the negative plate of the electrode assembly.