Electrode assembly and electrochemical device including the same

A separator comprising:

• a porous substrate made of a polymer material;
• a first porous coating layer on a first surface of the porous substrate, the first porous coating layer containing inorganic particles;
• and
• a second porous coating layer on a second surface of the porous substrate opposite the first surface, the second porous coating layer containing inorganic particles,
• wherein the separator has opposite ends and a central portion,
• wherein a thickness (Ts) of the porous substate decreases gradually from the opposite ends toward the central portion based on a longitudinal direction of the separator, a thickness of the central portion being constant,
• wherein a total thickness (Tc) of the first and second porous coating layers in end portions of the first porous coating layer and second porous coating layer increases gradually from the opposite ends toward the central portion,
• wherein a total thickness (Ts+Tc) of the separator is constant, and
• wherein the separator is folded in a zigzag manner.