Cylindrical secondary battery

Abstract

An aspect of the present invention relates to a cylindrical secondary battery including a bottomed cylindrical battery case having an opening, an electrode group, an electrolyte solution, the electrode group and the electrolyte solution being housed in the battery case, and a sealing member blocking the opening of the battery case. The electrode group includes a positive electrode, a negative electrode, and a separator placed between the positive electrode and the negative electrode and is formed by winding the positive electrode and the negative electrode with the separator therebetween. The negative electrode includes a negative electrode current collector and a negative electrode mix layer formed on at least one principal surface of the negative electrode current collector. The positive electrode includes a positive electrode current collector and a positive electrode mix layer formed on at least one principal surface of the positive electrode current collector. The separator includes an inner non-contact region which is located on the inner peripheral side of the electrode group and which has both surfaces that are in contact with none of the negative electrode mix layer and the positive electrode mix layer. The length of the inner non-contact region is 5% or more of the length of the separator in a winding direction of the electrode group. According to the present invention, a compact cylindrical battery with particularly excellent charge-discharge cycle characteristics in association with quick charge can be provided.