SOC ESTIMATION DEVICE AND SOC ESTIMATION METHOD

摘要

PROBLEM TO BE SOLVED: To accurately estimate an SOC (State Of Charge) of a secondary battery capable of being charged/discharged and reduce time required for estimating the SOC, with regard to an SOC estimation device and an SOC estimation method for estimating the SOC.SOLUTION: A measurement unit 1-1 measures a value of OCV of each of cells C1 to C5 at outflow start time of bypass current flowing in bypass circuits B1 to B5 and outflow time of the bypass current. A fluctuation transition estimation unit 1-2 estimates transition of fluctuation in the value of OCV of the cell after the outflow start of the bypass current on the basis of known SOC-OCV characteristic information showing relation between an SOC and OCV of a cell and the value of OCV at the outflow start time of the bypass current. An OCV value estimation unit 1-3 estimates a value of OCV in the case of outflow suspension of the bypass current on the basis of the transition of the fluctuation in the value of OCV. SOC value estimation means 1-4 estimates a value of SOC in the case of the outflow suspension of the bypass current from the value of OCV estimated by the OCV value estimation unit 1-3, on the basis of the SOC-OCV characteristic information.