| 摘要 |
PROBLEM TO BE SOLVED: To restrain output of a nonaqueous secondary battery from being excessively limited and also restrain the degradation of the nonaqueous secondary battery.SOLUTION: A current sensor detects a current value at charge and discharge time of the nonaqueous secondary battery. A controller calculates an evaluation value necessary to evaluate a first degradation component from the charge and discharge state detected using the current sensor and, when an integrated value derived by integrating evaluation values exceeding a target value exceeds a threshold, lowers an upper limit value. The first degradation component is a component which raises the resistance value of the nonaqueous secondary battery as the salt concentration of the nonaqueous secondary battery gets lopsided by its discharge. The controller calculates an integrated value and a resistance value before and after as a period in which the nonaqueous secondary battery is not charged nor discharged and, from the relationship between the integrated value and the resistance value, identifies a second degradation component which raises the resistance value of the nonaqueous secondary battery due to the deterioration of the materials constituting the nonaqueous secondary battery. The controller sets as a threshold a value which tolerates a rise in the resistance value by the first degradation component, not including the second degradation component. |
