NOVELTY - A battery cell (10) comprises: a stack (12) including at least one anode, at least one cathode and a separator that is electrically insulative between each anode and cathode; a pouch (14) including a first film (30) and a second film (32) and having a cavity (15) within the pouch between the first and second films, where the pouch holds the stack and electrolyte in the cavity; an anode terminal electrically connected to the anode and extending outwardly from the pouch; and a cathode terminal electrically connected to the cathode and extending outwardly from the pouch.    USE - As battery cell (claimed) such as pouch-type battery cells for battery packs for electric vehicles.    ADVANTAGE - The battery cell prevents the passage of oxygen and moisture through it; The pouch includes a flange that provide seal region with sealed subregions with an unsealed subregion between each adjacent pair of sealed subregions. This permits the flange to be folded in the unsealed subregions while reducing mechanical stress of the common sealing layer.    DETAILED DESCRIPTION - A battery cell (10) comprises: a stack (12) including at least one anode, at least one cathode and a separator that is electrically insulative between each anode and cathode; a pouch (14) including a first film (30) and a second film (32) and having a cavity (15) within the pouch between the first and second films, where the pouch holds the stack and electrolyte in the cavity; an anode terminal electrically connected to the anode and extending outwardly from the pouch; and a cathode terminal electrically connected to the cathode and extending outwardly from the pouch, where each of the first and second films includes a main barrier layer and a sealing layer, where the main barrier layer is metallic and prevents the passage of oxygen and moisture through it, where the sealing layer is inboard of the main barrier layer and protects the main barrier layer from exposure to the electrolyte, where the pouch further includes a flange (44) containing a seal region, where in the seal region the sealing layer from the first film is fixedly joined to the sealing layer from the second film so as to form a common sealing layer to seal the cavity, where the thickness of the common sealing layer at a point spaced distally from a proximal end of the seal region is smaller than the thickness of the common sealing layer at the proximal end of the seal region.    DESCRIPTION OF DRAWING(S) - The figure shows a sectional side view of a configuration for the flange for the battery cell.    Battery cell (10)    Stack (12)    Pouch (14)    Cavity (15)    First film (30)    Second film (32)    Flange (44) (44)