preparing a negative electrode roll on which a negative electrode structure is wound, wherein the negative electrode structure comprising a negative electrode current collector and a negative electrode active material layer formed on at least one surface of the negative electrode current collector;

preparing a pre-lithiation bath comprising a pre-lithiation solution, wherein the pre-lithiation bath is sequentially partitioned into an impregnation section, a pre-lithiation section, and an aging section;

impregnating the negative electrode structure with the pre-lithiation solution while unwinding the negative electrode structure from the negative electrode roll and moving the negative electrode structure through the impregnation section;

pre-lithiating the negative electrode structure while moving the negative electrode structure out of the impregnation section and moving the negative electrode structure through the pre-lithiation section; and

aging the negative electrode structure while moving the negative electrode structure out of the pre-lithiation section and moving the negative electrode structure through the aging section,

wherein the pre-lithiating of the negative electrode structure comprises:

(a) arranging a plurality of pre-lithiation rolls, wherein each roll is rotatable and comprises a core, a lithium metal layer formed on the core, and a separator layer formed on the lithium metal layer, in the pre-lithiation section in a movement direction of the negative electrode structure, and

(b) pre-lithiating the negative electrode structure by electrochemically charging the negative electrode structure while moving the negative electrode structure through the pre-lithiation section, wherein the negative electrode active material layer is in contact with the plurality of pre-lithiation rolls, and pressing the negative electrode structure with the plurality of pre-lithiation rolls, and

wherein the pressing pressures of the pre-lithiation rolls in contact with the negative electrode structure are increased as the negative electrode structure moves.