DEVICE AND METHOD FOR DETECTING STATE OF SECONDARY BATTERY

摘要

PROBLEM TO BE SOLVED: To accurately estimate SOH (State of Health) of a secondary battery even when SOC (State of Charge) and other conditions are changing.SOLUTION: A secondary battery state detection device 1 for detecting the state of a secondary battery 14 includes: computation means (CPU 10a) which computes a ratio of first internal resistance representing internal resistance of the secondary battery when an absolute SOC, computed as a standard initial capacity of the secondary battery, is within a predetermined range, and second internal resistance representing the internal resistance of the secondary battery in a fully charged or nearly fully charged state; and estimation means (CPU 10a) which estimates SOH of the secondary battery on the basis of correlation between the ratio computed by the computation means and SOH.