A battery cell including an electrode assembly including an active material and a foil and a can accommodating the electrode assembly is provided. The foil may include a first region covered with the active material and having a first thickness, a second region covered with the active material and extending from the first region, and a third region protruding from the second region, The third region may have a third thickness, greater than the first thickness, and the second region may have a second thickness, greater than the first thickness and less than the third thickness.