Method for Estimating State of Rechargeable Battery

A method for estimating a state of a lithium-ion battery with a control device including a computer to converge a voltage error using an adaptive filter, the adaptive filter including, as parameters, a standard deviation Qp of process noise and a standard deviation Rp of measurement noise that are related to correction of a positive-electrode solid-phase average ion concentration Cs,ave,p, and a standard deviation Qn of process noise and a standard deviation Rn of measurement noise that are related to correction of a negative-electrode solid-phase average ion concentration Cs,ave,n, and with respect to a positive-electrode OCP curve OCPp indicating a positive-electrode open-circuit potential Vp (V) in a positive-electrode solid-phase average ion concentration ratio θp and a negative-electrode OCP curve OCPn indicating a negative-electrode open-circuit potential Vn (V) in a negative-electrode solid-phase average ion concentration ratio θn, an absolute value of a derivative dVp/dθp of the positive-electrode OCP curve OCPp is multiplied by a ratio of the standard deviation Qp and the standard deviation Rp, and an absolute value of a derivative dVn/dθn of the negative-electrode OCP curve OCPn is multiplied by a ratio of the standard deviation Qn and the standard deviation Rn, the method comprising:

• changing a correction sensitivity of the positive-electrode solid-phase average ion concentration Cs,ave,p and the negative-electrode solid-phase average ion concentration Cs,ave,n that change in accordance with a state of charge (SOC) of the rechargeable battery.