Patent ID: 7276313

Claim:
A battery comprising: at least two unit cells, each of the at least two unit cells being provided with: an outer sheath film having a layered structure in which a resin film and a metal film are layered; a positive-electrode current collector; a negative-electrode current collector; a separator disposed between the positive-electrode current collector and the negative-electrode current collector; one positive electrode tab to which the positive-electrode current collector is connected and protruding from a first sealed portion of the outer sheath film to form a first extending portion to which a first connecting member is connected; one negative electrode tab to which the negative-electrode current collector is connected and protruding from a second sealed portion of the outer sheath film to form a second extending portion to which a second connecting member connected, the one positive electrode tab and the one negative electrode tab protruding in opposite directions with respect to a corresponding unit cell; a first polymer layer wholly disposed at a boundary area between the positive electrode tab and the layered structure of the outer sheath film; and a second polymer layer wholly disposed at a boundary area between the negative electrode tab and the layered structure of the outer sheath film, wherein the outer sheath film is quadrangular as viewed along a thickness direction thereof to have sides, and at least one of the positive electrode tab and the negative electrode tab protrudes from one side among the sides of the outer sheath film, and wherein a value resulting by subtracting a width of the at least one of the positive electrode tab and the negative electrode tab from a width of a corresponding one of the positive-electrode current collector and the negative-electrode current collector is equal to or less than the width of the at least one of the positive electrode tab and the negative electrode tab, and a cross sectional area of the at least one of the positive electrode tab and the negative electrode tab at the one side of the outer sheath film is less than a cross sectional area of only the outer sheath film at the side of the outer sheath film.