Patent ID: 6869723

Claim:
A nonaqueous-electrolyte secondary battery comprising: a battery casing; and a coiled electrode contained in said battery casing; wherein said coiled electrode comprises an elongated positive electrode, an elongated negative electrode, and a separator, said positive electrode and negative electrode separated by the separator and wound so that the positive wherein said positive electrode comprises a positive-electrode mix layer and a positive-electrode collector made of a metallic foil having a first surface, a second surface, an outermost end, and an innermost end; wherein said positive-electrode mix layer is not formed on either the first or second surface of the positive electrode collector at the outermost end of the positive electrode collector; wherein said positive-electrode mix layer is formed on either but not both of the first or second surfaces of the positive electrode collector at a position adjacent to the outermost end of the positive electrode collector; wherein said positive-electrode mix layer is formed on both the first and second surface of the positive electrode collector on at least a portion of the positive electrode collector; wherein said negative electrode comprises a negative-electrode mix layer containing a negative-electrode material which permits lithium ions to be doped/dedoped and a negative-electrode collector made of a metallic foil having a first surface, a second surface, an outermost end, and an innermost end; wherein said negative-electrode mix layer is not formed on either the first or second surface of the negative electrode collector at the outermost end of the negative electrode collector; wherein said negative-electrode mix layer material is formed on both the first and second surface of the negative electrode collector on at least a portion of the negative electrode collector; wherein a negative electrode lead is formed on the outermost end of the outer surface of the negative electrode collector; wherein the outermost end of said negative-electrode collector is positioned, in the direction of the innermost ends to the outermost ends of the negative-electrode and positive electrode collectors, more forward than the outermost wherein d is the diameter of the coil electrode and L is the distance from the outermost end of said negative-electrode collector t3 the outermost end of said positive-electrode collector and the relationship 0<L≦πd is satisfied; and wherein insulating members are placed on the two vertical surfaces of the coiled electrode.