Battery and method for manufacturing same

A method for manufacturing a battery comprising:

• an electrode body in which at least one positive electrode and at least one negative electrode are spirally wound with at least one separator interposed therebetween;
• and
• a cylindrical exterior package can which receives the electrode body within a closed interior of the exterior package can,
• wherein the electrode body includes a lead connected to one of the positive electrode and the negative electrode, wherein the lead is enclosed within the closed interior of the cylindrical exterior package can and interposed between the electrode body and a circular base portion of the cylindrical exterior package can,
• the lead is an elongated rectangular piece of metal having an end portion thereof protruding from the electrode body toward the circular base portion of the cylindrical exterior package can, wherein the end portion of the lead has an L-shaped profile defined by:
• a first section that extends parallel to a winding axis of the electrode body, and
• a second section that extends parallel to the circular base portion of the cylindrical exterior package can,
• wherein the second section of the end portion of the lead defines a U-shaped portion having a cross-sectional U shape including an inside section, and an outside section opposite the inside section,
• wherein the circular base portion of the cylindrical exterior package can, the inside section, and the outside section are configured to overlap each other when viewed in a thickness direction of the circular base portion of the cylindrical exterior package can, and
• the cylindrical exterior package can and at least a part of a portion of the U-shaped portion which is in contact with the cylindrical exterior package can are welded to each other with a welding portion formed by energy beams radiated from the outside of the cylindrical exterior package can,
• wherein the welding portion extends from the circular base portion of the cylindrical exterior package can through an entirety of the outside section and only a part less than entirety of the inside section in the thickness direction of the circular base portion of the cylindrical exterior package can, and
• the welding portion is located to face a winding core portion including the winding central axis of the electrode body,
• the method comprising:
• a welding step of welding the lead to the exterior package can while the lead connected to one of the positive electrode and the negative electrode is folded,
• wherein in the welding step, energy beams are radiated from the outside of the exterior package can to an area of the exterior package can which faces a part of the U-shaped portion of the lead in contact with the exterior package can to weld the exterior package can and the lead to each other with the welding portion,
• wherein in the welding step, a pressing bar is inserted into the exterior package can to press the U-shaped portion against the portion of the exterior package can.