Secondary Battery Control Device

The life of a secondary battery has not been able to be prolonged due to deterioration of the secondary battery. In one step, whether a difference between an average value of a negative electrode capacity deviations calculated in a different step and a negative electrode capacity deviation calculated in another step is larger than a predetermined value is determined. In a case where the average value of the measured negative electrode capacity deviations is larger than the ideal negative electrode capacity deviation, and deterioration of the negative electrode capacity deviation is proceeding, a secondary battery is controlled to operate at a high voltage in a further step. With the control, the deterioration of the negative electrode capacity deviation is suppressed and the life of the secondary battery is prolonged. Further, in a case where an average value of the measured positive electrode use rates is lower than an ideal positive electrode use rate, and the deterioration of the positive electrode use rate is proceeding, an upper limit current of the secondary battery is lowered and the secondary battery is controlled to operate in still further step. With the control, the deterioration of the positive electrode use rate is suppressed, and the life of the secondary battery is prolonged.