METHOD FOR DETERMINING THE CHARGE STATE OF A BATTERY PACK

摘要

The invention relates to a method for determining the charge state of a battery pack consisting of a number "N" of individual battery cells, comprising the following steps: in the first step (S1), the charge state of each individual battery cell SOCi is determined for all i=1,N. In a second step (S2), the mean value of the charge states of the individual battery cells, mean (SOCi), is determined. This is followed by a third step (S3) of determining a weighting "w" from the equation where w = gw(mean(SOCi)), wherein the following applies for the function gw(SOC): the function value tends towards a minimum value of wmin when the argument tends toward the minimum charge state of a complete discharge SOCmin; the function value tends toward a maximum value of wmax when the argument tends towards the maximum charge state of a complete charge SOCmax; and the function gw() is continuous. Finally the charge state of the entire battery pack SOCp is determined according to SOCp = w/(wmax-wmin) * max (SOCi) + ( 1 - w/(wmax-wmin) ) * min (SOCi).