SEPARATOR FOR ELECTROCHEMICAL DEVICE, ELECTROCHEMICAL DEVICE

A separator for an electrochemical device may include a main plate; and a plurality of walls disposed on one or both of a first surface and a second surface of the main plate. The plurality of walls include a plurality of first walls having a shape extending in a first direction, and a plurality of second walls having a shape extending in a second direction, different from the first direction, wherein, among the plurality of first walls, some regions of two adjacent first walls overlap each other in a direction, perpendicular to the first direction and the remaining regions of two adjacent first walls do not overlap each other, and wherein, among the plurality of second walls, some regions of two adjacent second walls overlap each other in a direction, perpendicular to the second direction and the remaining regions of two adjacent second walls do not overlap each other.