SECONDARY BATTERY DETERIORATION DEGREE ESTIMATION DEVICE AND SECONDARY BATTERY DETERIORATION DEGREE ESTIMATION METHOD

To highly accurately estimate a secondary battery deterioration degree without charging and discharging.SOLUTION: An ECU performs processing including: a step (S102) of acquiring temperature and voltage if execution conditions for deterioration degree estimation are satisfied (YES in S100); a step (S106) of setting temperature before change and voltage before change, in the case of initial acquisition (YES in S104); a step (S110) of setting temperature after change and voltage after change if, in the case of not initial acquisition (NO in S104), the magnitude of a difference between temperature TB acquired immediately before and temperature before change is greater than a threshold or the magnitude of a difference between voltage acquired immediately before and voltage before change is greater than a threshold (YES in S108); a step (S112) of calculating a first tilt; and a step (S114) of estimating a deterioration degree.SELECTED DRAWING: Figure 5 【課題】充放電を行なうことなく二次電池の劣化度を精度高く推定する。【解決手段】ＥＣＵは、劣化度推定の実行条件が成立すると（Ｓ１００にてＹＥＳ）、温度および電圧を取得するステップ（Ｓ１０２）と、初回取得であると（Ｓ１０４にてＹＥＳ）、変化前温度と変化前電圧とを設定するステップ（Ｓ１０６）と、初回取得でないと（Ｓ１０４にてＮＯ）、直前に取得した温度ＴＢと変化前温度との差分の大きさがしきい値よりも大きいか、あるいは、直前に取得した電圧と変化前電圧との差分の大きさがしきい値よりも大きいと（Ｓ１０８にてＹＥＳ）、変化後温度と変化後電圧とを設定するステップ（Ｓ１１０）と、第１傾きを算出するステップ（Ｓ１１２）と、劣化度を推定するステップ（Ｓ１１４）とを含む、処理を実行する。【選択図】図５