Method of manufacturing battery

A method of manufacturing a battery including a wound electrode assembly wherein a first separator, a negative electrode plate, a second separator, and a positive electrode plate are wound together, the method comprising the steps of:

• (A) suction-attaching the first separator to a winding core;
• and
• (B) winding the first separator onto the winding core, wherein:
• the winding core includes a plurality of suction holes for suction-attaching the first separator;
• and
• greater than or equal to 80% by aperture area ratio of the suction holes are formed in a first region of the winding core, wherein the first region is defined by dividing an outer circumferential surface of the winding core into four equal parts, the four equal parts respectively being first to fourth regions starting from a position of the winding core that faces a starting end of winding of the first separator of the wound electrode assembly.