CELL COATED WITH FILM AND MANUFACTURING METHOD THEREOF

A film-covered battery 1 includes battery element 6 and laminate films 3 and 4 for sealing battery element 6. Laminate films 3 and 4 are realized by laminating a heat-seal resin layer and a metal foil layer and seal battery element 6 by arranging the films on either side of battery element 6 with the heat-seal resin layers disposed on the inside and then heat-sealing at sealing areas 3a and 4a on the outer peripheries of the films. The areas of the laminate films 3 and 4 other than sealing areas 3a and 4a are electron beam irradiation areas 3b and 4b that are irradiated by an electron beam. Cross-linked structures are formed in the heat-seal resin layers of electron beam irradiation areas 3b and 4b by irradiation by an electron beam.