METHOD OF ESTIMATING FULL CHARGE CAPACITY AFTER DEGRADATION OF BATTERY, AND METHOD OF CREATING ESTIMATING EQUATION FOR FULL CHARGE CAPACITY AFTER DEGRADATION

Through an experiment or the like, a degradation contribution relation representing a relation between each of N battery state-related variables and a decrease in full charge capacity is obtained. Historical data on the variables is collected from L battery electric vehicles, and L simple estimated values of full charge capacity after degradation are obtained by using the degradation contribution relations. A correlation coefficient between the L historical data sets on each variable and the L simple estimated values is calculated, and M variables having the correlation coefficient exceeding a predetermined threshold are selected. An equation is formulated where the selected variables are explanatory variables and a high-accuracy estimated value of full charge capacity after degradation is an objective variable. The coefficients are determined by substituting K historical data sets into the variables of the equation and substituting K simple estimated values into a left side of the equation.