Patent ID: 6479967
Filing Date: 2002-11-12
Classification: B60L,G01R

Abstract:
A method of controlling the discharging of a battery including a plurality of modules each consisting of at least one secondary storage cell, which method includes the following steps:(a) a voltage Vz(tn) of each module z and a discharge current I(tn) are measured synchronously at time tn, (b) the internal resistance IRz(tn) of each module z is calculated as follows: IRz(tn)=Vz(tn)/I(tn), (c) a voltage Vz(tn+1) of each module z and a discharge current I(tn+1) are measured synchronously at time tn+1, (d) the internal resistance IRz(tn+1) of each module z is calculated as follows: IRz(tn+1)=Vz(tn+1)/I(tn+1), (e) the slope of the variation in the internal resistance IRSz of each module z is calculated between times tn and tn+1 as follows: IRSz=[IRz(tn+1)âˆ’IRz(t)]/I(tn), (f) the maximum value IRSmax and the average value IRSavg of the slopes of the variation in the internal resistance of all the modules are calculated, (g) a difference DIRS is calculated as follows: DIRS=IRSmaxâˆ’IRSavg, (h) the difference DIRS is compared to a criterion K determined experimentally, and (i) the first phase of discharging is stopped when DIRS is greater than or equal to K, following correction of the rate of change dl/dt of the discharging current I(t).