A system includes a battery cell having an internal heat fin and a first electrically insulating layer disposed over at least a portion of a single side of the internal heat fin. The battery cell includes an electrochemical stack disposed above the first insulating layer and the internal heat fin in a stack. The battery cell also includes a pouch material film configured to hermetically seal with one side of the internal heat fin or the first insulating layer about the electrochemical stack such that the internal heat fin forms an outer boundary of the battery cell. The pouch material film includes a metallic foil layer disposed between a second electrically insulating layer and a third electrically insulating layer.