Patent ID: 7981548

Claim:
A multilayer secondary battery, comprising: a positive electrode including a positive electrode active substance layer formed on a flat, sheet-form positive electrode collector; and a negative electrode including a negative electrode active substance layer formed on a flat sheet-form negative electrode collector; a separator that separates the positive electrode and the negative electrode, the positive electrode, the negative electrode and the separator being stacked together with the positive electrode and the negative electrode on opposite sides of the separator, wherein the positive electrode active substance layer differs in area from the negative electrode active substance layer, active substance-free portions with no active substance layer coated on them are formed on at least adjoining two sides of an outer periphery of a collector of a smaller area electrode having a smaller active substance layer area, wherein the active substance-free portions of the collector are formed only on a side of the collector opposite to a side from which an electrode lead terminal extends and on a side of the collector adjacent to the side from which the electrode lead terminal extends, a surface of the collectors at the active substance-free portions is covered with an insulating substance layer, and an end face of the insulating substance layer that faces away from a side contiguous to an active substance layer and an end face of a larger area electrode having a larger active substance layer area are located and stacked together on the same plane that intersects vertically an electrode plane.