LASER WELDING METHOD, LASER WELDING SYSTEM, AND METAL BONDED BODY

In a laser welding method, for example, in a first step, a first member and a second member having a convex curved surface convex toward the first member are brought relatively close to each other, a plurality of metal foils are compressed in a state of being interposed between the first member and the convex curved surface in a layering direction, and a compressed portion curved in a state of protruding in a first direction along the curved surface is thereby formed in the plurality of metal foils such that at least a metal foil positioned at an end portion of the compressed portion in the first direction is plastically deformed partially. In a second step after the first step, a portion of the plurality of metal foils including the compressed portion and a metal material are joined together in a state where the end portion of the compressed portion in the first direction and the metal material are in contact with each other.