Rechargeable battery

A rechargeable battery comprising:

• an electrode assembly;
• a case including a sealing portion surrounding the electrode assembly;
• and
• a lead electrically connected to the electrode assembly and extending in a first direction, the lead including a conductive metal portion and a film portion, the conductive metal portion being one monolithic conductor,
• wherein the conductive metal portion of the lead includes:
• a first region in contact with the electrode assembly and located inside the case;
• a second region exposed to an outside of the case;
• and
• a third region located between the first region and the second region and overlapping the sealing portion of the case,
• wherein the third region has a width greater than that of the first region and the second region in a second direction, and a thickness of the entire third region is smaller than thicknesses of the first region and the second region in a third direction,
• wherein the second direction is perpendicular to the first direction, and the third direction is perpendicular to the first direction and the second direction, and
• wherein the film portion and the sealing portion of the case overlap the third region, and do not overlap with the first region and the second region and are spaced apart from a first boundary between the first region and the third region and a second boundary between the second region and the third region, respectively.