BATTERY STATE ESTIMATION DEVICE, BATTERY STATE ESTIMATION METHOD AND PROGRAM

To accurately estimate a state of charge of a secondary battery.SOLUTION: A battery state estimation device 200 comprises: a first estimation unit 210 for successively calculating a first estimate charge rate SOC1 which is an estimate of a charge rate SOC of a battery 100 and a current offset estimate Ioe which is an estimate of a current offset value Io of the battery 100 on the basis of an output current I which is a charge current or a discharge current of the battery 100, an output voltage V of the battery 100 and a cell surface temperature Ts of the battery 100 in a case where a predetermined condition is not established; and a second estimation unit 220 for successively calculating a temperature deviation estimate ΔTx which is an estimate of a deviation relating to a temperature of the battery 100, and a second estimate charge rate SOC2 which is the other estimate of the charge rate SOC, on the basis of the output current I, the output voltage V, the cell surface temperature Ts and a current offset specific estimate Ioes which is the current offset estimate Ioe in a case where the condition is changed from a non-established state to an established state, when the condition is established.SELECTED DRAWING: Figure 1 【課題】二次電池の充電状態を正確に推定する。【解決手段】電池状態推定装置２００は、所定の条件が非成立である場合に、電池１００の充電電流または放電電流である出力電流Ｉと、電池１００の出力電圧Ｖと、電池１００のセル表面温度Ｔｓと、に基づいて、電池１００の充電率ＳＯＣの推定値である第１の推定充電率ＳＯＣ１と、電池１００の電流オフセット値Ｉｏの推定値である電流オフセット推定値Ｉｏｅと、を逐次算出する第１の推定部２１０と、条件が成立する場合に、出力電流Ｉと、出力電圧Ｖと、セル表面温度Ｔｓと、条件が不成立状態から成立状態に変化した時の電流オフセット推定値Ｉｏｅである電流オフセット特定推定値Ｉｏｅｓと、に基づいて、電池１００の温度に関する偏差の推定値である温度偏差推定値ΔＴｘと、充電率ＳＯＣの他の推定値である第２の推定充電率ＳＯＣ２と、を逐次算出する第２の推定部２２０と、を備える。【選択図】図１