State-of-charge estimation method

Abstract

Provided is a state-of-charge estimation method that includes: obtaining a plurality of pseudo-SOC values before depolarization, based on a cell voltage after a batteryis continuously charged or discharged and the charging or discharging is stopped; setting an initial value for an estimated SOC value that is estimated as a post-depolarization SOC; obtaining a Δ-pseudo-SOC value that is a difference between each of the pseudo-SOC values and the estimated SOC value; obtaining a correlation between a square of the Δ-pseudo-SOC value and a rate of change of the Δ-pseudo-SOC value; classifying the correlation into a first region in which there is non-linear change and a second region in which there is linear change, and obtaining a regression line for the second region; and using the regression line to correct the estimated SOC value such that the estimated SOC value approaches a post-depolarization true SOC value.