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

Abstract

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 () 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 Vas 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 () calculates the terminal voltage of the secondary battery as the open circuit voltage V. An estimated charge/discharge electricity amount calculation part () uses a preset change-in-voltage adjustment constant ΔV/adjustment coefficient K, change-in-electromotive-force constant Kand polarization voltage generation constant Kto calculate the estimated charge/discharge electricity amount ΔQas a function of the change ΔVin the no-load voltage or the open circuit voltage over a predetermined period of time.