Abstract: A cylindrical battery includes a bottom-closed cylindrical exterior package can which receives an electrode body. A lead connected to one of a positive electrode and a negative electrode of the electrode body is extended from the electrode body and is welded to a bottom portion of the exterior package can. When the bottom portion is viewed from the outside of the exterior package can, at least a part of the welding portion between the lead and the bottom portion formed by a molten mark is formed outside of a concentric circle of the bottom portion which has a diameter equivalent to the width of the lead.

Abstract: A sealed cell includes a bottomed cylindrical outer casing can. The outer casing can is formed by nickel-plated iron, and a lead connected to one of a positive electrode and a negative electrode, and the outer casing can, are welded by a welding part formed from the outside surface of the outer casing can toward the lead. The welding part is formed by molten traces and has a first layer and a second layer having a higher nickel concentration than the first layer. The first layer is formed from the lead through to the inside of the outer casing can, the second layer is formed so as to adjoin the first layer on the outside surface side of the outer casing can, and the whole of the first layer is covered with the second layer when the welding part is viewed from the outside of the outer casing can.

Abstract: A cylindrical battery includes a bottom-closed cylindrical exterior package can which receives an electrode body. A lead connected to one of a positive electrode and a negative electrode of the electrode body is extended from the electrode body and is welded to a bottom portion of the exterior package can. When the bottom portion is viewed from the outside of the exterior package can, at least a part of the welding portion between the lead and the bottom portion formed by a molten mark is formed outside of a concentric circle of the bottom portion which has a diameter equivalent to the width of the lead.

Abstract: A sealed cell includes a bottomed cylindrical outer casing can. The outer casing can is formed by nickel-plated iron, and a lead connected to one of a positive electrode and a negative electrode, and the outer casing can, are welded by a welding part formed from the outside surface of the outer casing can toward the lead. The welding part is formed by molten traces and has a first layer and a second layer having a higher nickel concentration than the first layer. The first layer is formed from the lead through to the inside of the outer casing can, the second layer is formed so as to adjoin the first layer on the outside surface side of the outer casing can, and the whole of the first layer is covered with the second layer when the welding part is viewed from the outside of the outer casing can.