SECONDARY BATTERY STATE DIAGNOSING METHOD AND STATE DIAGNOSING DEVICE

To provide a secondary battery state diagnosing method and a secondary battery state diagnosing device with which it is possible to diagnose the degradation state of a secondary battery with high accuracy, on the basis of information that can be acquirable with a simple operation.SOLUTION: The secondary battery state diagnosing method includes steps for: obtaining a calculation result that indicates a relationship between the charge state and the closed-circuit voltage of a secondary battery, on the basis of a relationship between the charge state and the open-circuit voltage of the secondary battery and a relationship between the charge state and the internal resistance of the secondary battery; and comparing a measurement result that indicates the relationship between the charge state and the closed-circuit voltage of the secondary battery with a calculation result that indicates the relationship between the charge state and the closed-circuit voltage of the secondary battery, the measurement result acquired by successively conducting measurement for each charge state of the secondary battery, in a charge process and a discharge process of the secondary battery. The secondary battery state diagnosing device comprises an acquisition unit for acquiring measured data that indicates the relationship between the charge state and the closed-circuit voltage of the secondary battery, a storage unit, and a computation unit. The measured data is inputted to the acquisition unit in the charge or discharge process of the secondary battery after being acquired by successively conducting measurement for each charge state of the secondary battery.SELECTED DRAWING: Figure 2 【課題】二次電池の劣化状態を簡便な操作で取得できる情報に基づいて高精度に診断することができる二次電池の状態診断方法および二次電池の状態診断装置を提供する。【解決手段】二次電池の状態診断方法は、二次電池の充電状態と開回路電圧との関係と、二次電池の充電状態と内部抵抗との関係とに基づいて、二次電池の充電状態と閉回路電圧との関係を示す計算結果を求める工程と、二次電池の充電状態と閉回路電圧との関係を示す測定結果と、二次電池の充電状態と閉回路電圧との関係を示す計算結果とを比較する工程とを含み、測定結果は、二次電池の充電過程または放電過程において、二次電池の充電状態毎の測定を連続的に行って取得される。二次電池の状態診断装置は、二次電池の充電状態と閉回路電圧との関係を示す測定データを取得する取得部と、記憶部と、演算部とを備え、測定データは、二次電池の充電過程または放電過程において、二次電池の充電状態毎の測定を連続的に行って取得された後に取得部に入力される。【選択図】図２