ECU executes program including the steps of turning on an overcharge tentative determination flag and performing limitation on Win in a case where a rising rate ΔTB is higher than or equal to ΔTB(0), and a current average value IBs is a value on a side of charging, and the steps of turning off the overcharge tentative determination flag and cancelling the limitation on Win in a case where the rising rate ΔTB is lower than or equal to ΔTB(1), or the current average value IBs exhibits a value on a side of discharging, and the steps of determining that a battery is in the overcharging state and executing a fail safe process in a case where the integrated value IBs of current from a time point at which the overcharge tentative determination flag is switched from an off-state to an on-state becomes greater than or equal to IBs(0).