Secondary battery comprising two electrode assemblies

A secondary battery including a first electrode assembly (110) including first and second electrode plates (10, 20) stacked on each other; and a second electrode assembly (120) including third and fourth electrode plates (30, 40), wherein the second electrode assembly (120) is wound along an outer circumference of the first electrode assembly (110). The secondary battery has a high energy density and is capable of preventing damage of the electrode plates.