Patent ID: 10505231

Abstract:
A lithium ion secondary battery element includes: a positive electrode that includes a positive electrode current collector including a positive electrode active material applied part where a positive electrode active material is applied to form a positive electrode active material layer, and including a positive electrode active material non-applied part where the positive electrode active material is not applied, the positive electrode active material layer including a positive electrode active material layer flat part and a positive electrode active material layer thin part that is thinner than the positive electrode active material layer flat part, and the positive electrode further including an insulating member that covers at least a part of the positive electrode active material layer thin part and at least a part of the positive electrode active material non-applied part; a separator; and a negative electrode that includes a negative electrode current collector including a negative electrode active material applied part where a negative electrode active material is applied to form a negative electrode active material layer, and including a negative electrode active material non-applied part where the negative electrode active material is not applied, wherein: the positive electrode, the separator, and the negative electrode are stacked in this order; and the positive electrode active material non-applied part and the negative electrode active material non-applied part face each other through the separator.