Patent ID: 10302706

Abstract:
In an apparatus, an OCV calculator measures a close circuit voltage (CCV) across an equivalent circuit of a storage battery, and calculates an open circuit voltage (OCV) across the storage battery based on the CCV, the equivalent circuit, and a current flowing through the storage battery. The equivalent circuit simulates an electrochemical behavior of the storage battery. The equivalent circuit includes the OCV as a power supply voltage and a predetermined internal impedance connected in series to the power supply voltage. The internal impedance includes a capacitance. A calculator calculates an SOC of the storage battery as a function of the OCV. A determiner determines whether the capacitance is saturated as a function of an electrical parameter associated with a charge stored in the capacitance. A diagnosing unit diagnoses whether the SOC of the storage battery is appropriate according to whether the capacitance is saturated.