Method and device for estimating charge/discharge electricity amount of secondary cell

摘要

The present invention provides an apparatus that can estimate the charge/discharge electricity amount without being affected by current measurement error. If specific selection conditions are met, a no-load voltage calculation part ( 105 ) takes a plurality of pairs of data consisting of current data I(n) and voltage data V(n) corresponding to the current data and calculates a no-load voltage V_sep as the voltage intercept at a current of zero in a straight-line approximation obtained by statistical processing such as regression analysis using a least squares method with respect to the plurality of pairs of data. In addition, if specific current conditions continue to be met for a certain amount of time, an open circuit voltage calculation part ( 106 ) calculates the terminal voltage of the secondary battery as the open circuit voltage V_oc. An estimated charge/discharge electricity amount calculation part ( 114 ) uses a preset change-in-voltage adjustment constant DeltaV_bc/adjustment coefficient K_b, change-in-electromotive-force constant K_eq and polarization voltage generation constant K_pol to calculate the estimated charge/discharge electricity amount DeltaQ_e as a function of the change DeltaV_b in the no-load voltage or the open circuit voltage over a predetermined period of time.