Electrified vehicle battery state-of-charge monitoring with aging compensation

Abstract

Determination of an electric vehicle battery state-of-charge (SOC) based on measuring open circuit voltage is subject to error as the relationship changes over time. A method is provided for updating the relationship during aging. A charging current is applied to the battery cell. A favorable charging condition is detected in response to a predetermined charging current. A charging slope vector is compiled during the charging condition comprising a plurality of slope values over respective state-of-charge increments. A plurality of SOC-OCV slope vectors are determined corresponding to a plurality of stored SOC-OCV aging curves, each SOC-OCV slope vector comprising a plurality of slope values over equivalent state-of-charge increments. One of the stored SOC-OCV aging curves is selected having an SOC-OCV slope vector best fitting the charging slope vector for use in converting measured OCV values to battery cell SOC values.

Dependencies are inferred from the claim text.