Secondary battery charge/discharge electricity amount estimation method and device, secondary battery polarization voltage estimation method and device and secondary battery remaining capacity estimation method and device

Abstract

If a particular selection condition is satisfied, a non-load voltage calculation unit () calculates a no-load voltage Vsep as a voltage piece when the current in approximate straight line obtained by statistical processing using the method of least squares for a plurality of sets of data containing current data I(n) and voltage data V(n) is zero. If a particular current condition or voltage condition is continuously satisfied for a predetermined time, an open-circuit voltage calculation unit () calculates a secondary cell terminal voltage as an open-circuit voltage Voc and a voltage-at-zero-current storing unit () stores voltage-at-zero-current Vzo calculated by a voltage-at-zero-current calculation unit (). By using a predetermined voltage change amount adjustment constant ΔVbc/adjustment coefficient Kb, an electromotive force change constant Keq, and a polarization voltage generation constant Kpol, an estimated charge/discharge electric amount calculation unit (A) calculates an estimated charge/discharge electricity amount ΔQe as a function of the change amount ΔVzo of a voltage-at-zero-current Vzo. It is possible to estimate charge/discharge electricity amount without being affected by the current measurement error.