A battery includes a power generation component including a positive electrode, a negative electrode, and an electrolyte, and a battery case accommodating the power generation component. The negative electrode includes a first lead (17) having a single layer structure whose main component is nickel, and a second lead (18) having a layered structure including a Ni layer (18a) whose main component is nickel and a Cu layer (18b) whose main component is copper. The battery includes a layered portion (35) formed of the leads that are superposed such that the Ni layer (18a) of the second lead (18) faces the first lead (17). Part of the layered portion (35) is welded to an inner surface of the battery case with the first lead (17) at the layered portion (35) being disposed on a battery case side.