主权项 |
1. A method for use with a series array of a plurality of electrochemical cells, each cell having a respective state of charge, the method comprising the steps of:
measuring discharge current during a first measurement interval, said current measurement during the first measurement interval carried out across a predetermined bandwidth; measuring cell terminal voltage for a first one of the cells during the first measurement interval, said voltage measurement during the first measurement interval carried out across the predetermined bandwidth; measuring discharge current during a second measurement interval, said current measurement during the second measurement interval carried out across a predetermined bandwidth; measuring cell terminal voltage for a second one of the cells during the second measurement interval, said voltage measurement during the second measurement interval carried out across the predetermined bandwidth; deriving information indicative of a respective effective internal impedance for each of the first one of the cells and the second one of the cells, said derived effective internal impedance having not only a pure ohmic component but also frequency dependent component, said derived effective internal impedance defining a magnitude greater than that of the pure ohmic component taken alone; deriving information indicative of a respective effective internal cell voltage for each of the first one of the cells and the second one of the cells; identifying a particular one of the first one of the cells and the second one of the cells having a lower effective internal cell voltage and a higher magnitude of effective internal impedance; and topping up the state of charge of the identified cell. |