An embodiment of the present invention provides an electrode assembly in which a first electrode having a first electrode coated region and a first electrode uncoated region, a separator, and a second electrode having a second electrode coated region and a second electrode uncoated region are stacked and wound around a winding axis, wherein the first electrode coated region may include a first substrate, a first small electrode portion including first active material layers formed on both surfaces of the first substrate, and a second small electrode portion including a first active material layer formed on the other surface of the first substrate in which one surface thereof is exposed, and the second small electrode portion may be positioned at a first curved portion formed by first winding of the electrode assembly.