Degradation factor estimation method and remaining life estimation method

摘要

PROBLEM TO BE SOLVED: To provide a deterioration factor estimation method capable of easily estimating a dominant deterioration factor of a secondary cell and a remaining life time estimation method for estimating a remaining life time of the secondary cell.SOLUTION: An internal resistance measuring process measures an internal resistance R1 of a secondary cell in a low charge rate SOC1; and an internal resistance R2 of the secondary cell in a high charge rate SOC2. An estimation process obtains an internal resistance change rate R' by dividing a differential value R(=R2-R1) of an internal resistance R by a differential value SOC(=SOC2-SOC1). When the internal resistance change rate R' is equal to or more than a reference value RS, it is estimated that standing deterioration is dominant. As a result, there is no need to store a use history of the secondary cell, and the dominant deterioration factor can be easily estimated.SELECTED DRAWING: Figure 3