ESTIMATION METHOD OF BINDING LOAD OF SECONDARY BATTERY

To enhance accuracy of estimation of a binding load applied to a secondary battery.SOLUTION: On the basis of a battery temperature of a secondary battery, detected in charging or discharging of the secondary battery and detection data of a current, a first frequency distribution indicating a frequency distribution of a current integration value against the battery temperature of the secondary battery in the charging or the discharging of the secondary battery is generated. Also, on the basis of this first frequency distribution and calculation data of a change amount of a charging state of the secondary battery in the charging or the discharging, a second frequency distribution indicating the frequency distribution of the change amount in the charging state of the secondary battery against the battery temperature or the current integration value of the secondary battery in the charging or the discharging of the secondary battery is generated. On the basis of the second frequency distribution, an increase factor of a binding load applied to the secondary battery is calculated, and an increase amount of the binding load in the secondary battery is calculated after the charging or the discharging in this time by using them.SELECTED DRAWING: Figure 4 【課題】二次電池に付与される拘束荷重の推定の精度を高める。【解決手段】二次電池の充電又は放電中に検出された二次電池の電池温度及び電流の検出データに基づいて、二次電池の充電又は放電中における二次電池の電池温度に対する電流積算値の頻度分布を示す第１頻度分布が生成される。また、この第１頻度分布と、充電又は放電中における二次電池の充電状態の変化量の計算データとに基づいて、二次電池の充電又は放電中における二次電池の電池温度及び電流積算値に対する二次電池の充電状態の変化量の頻度分布を示す第２頻度分布が生成される。第２頻度分布に基づいて、二次電池に付与される拘束荷重の増加係数が計算され、これを用いて今回の充電又は放電後に二次電池における拘束荷重の増加量が計算される。【選択図】図４