Abstract
To estimate a deterioration parameter of a storage battery, evaluate deterioration of the storage battery, and predict the battery life.SOLUTION: A method for evaluating deterioration of a storage battery by estimating deterioration parameter by fitting discharge curves of a cathode and an anode to a discharge curve of the storage battery includes the steps of: determining whether soundness of the storage battery is higher than a predetermined value; searching for a single set of deterioration parameter if the soundness of the storage battery is higher than a predetermined value; and determining that the storage battery is deteriorating over time and searching for multiple sets of deterioration parameters if the soundness of the storage battery is equal to or less than the predetermined value.