SECONDARY BATTERY IMPEDANCE EVALUATION METHOD AND SECONDARY BATTERY IMPEDANCE EVALUATION APPARATUS

摘要

PROBLEM TO BE SOLVED: To provide a method capable of relatively easily evaluating the impedance of a secondary battery in use in a nondestructive manner.SOLUTION: A secondary battery impedance evaluation method comprises: a step (1) of measuring a current change I(t) and a voltage change V(t) of the secondary battery depending on a load variation; a step (2) of subjecting the current change I(t) of the secondary battery to wavelet transform to acquire first frequency domain data P(f), and subjecting the voltage change V(t) to wavelet transform to acquire second frequency domain data P(f); and a step (3) of calculating an impedance spectrum of the secondary battery from the first and second frequency domain data.