SECONDARY BATTERY SYSTEM AND SOC VALUATION METHOD FOR A SECONDARY BATTERY

摘要

A secondary battery system comprises: a secondary battery (10) having an electrode (115) containing an active material; and an electronic control unit (100) configured to execute an SOC estimating process for estimating a SOC of the secondary battery. The electronic control unit is configured to: i) calculate the surface tension from a usage history of the secondary battery; ii) calculate an amount of change in OCV from the calculated surface tension; iii) correct an estimated OCV using the OCV change amount; wherein the estimated OCV is estimated from a voltage value and a current value of the secondary battery; and iv) estimate an SOC corresponding to the corrected estimated OCV as the SOC of the secondary battery.