Method of self-discharge test for secondary battery and manufacturing method for secondary battery

Abstract

A method of self-discharge test for a battery including an electrode body provided with a positive electrode plate including a positive active material layer and a negative electrode plate including a negative active material layer. The method includes a process of voltage adjusting to adjust a battery voltage to a first battery voltage and a process of self-discharge testing to keep the battery in a terminal open state for a predetermined term and to inspect a state of self-discharge of the battery from variations in the battery voltage occurred during the predetermined term. The voltage adjusting is to adjust the battery voltage to the first battery voltage having magnitude, for which a variation settled time of settling a variation amount of the battery voltage varied by Li diffusion to lessen a concentration gap of an opposing-portion concentration and a non-opposing portion concentration, is set as 17 hours or less.