SECONDARY BATTERY

• Main Author: NISHIIE, Daiki
• Format: Patent
• Language: English
• Published: 25.05.2023
• Subjects: BASIC ELECTRIC ELEMENTS; ELECTRICITY; PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSIONOF CHEMICAL INTO ELECTRICAL ENERGY

Provided is a secondary battery including: a power storage element having an elongated cylindrical shape, a positive electrode having a positive electrode active material layer formed on a positive electrode current collector and a negative electrode having a negative electrode active material layer formed on a negative electrode current collector being wound around the power storage element; and an exterior body, in which at least two folding positions are provided on either the positive electrode or the negative electrode located at an innermost periphery of the power storage element, and when a distance between an end portion of the positive electrode active material layer on a winding start end portion side of the positive electrode and the folding position close to the end portion of the positive electrode active material layer is designated as a distance C1, a distance between an end portion of the positive electrode active material layer on a winding finish end portion side of the positive electrode and the folding position close to the end portion of the positive electrode active material layer is designated as a distance C2, and a length of the power storage element in a longitudinal direction is designated as W, the secondary battery satisfies relational expressions (1) and (2) below:0.02≤C1/W≤0.12   Expression (1)0.02≤C2/W≤0.12   Expression (2).