The model of electromotive force-impedance estimating the SOC of battery online

This paper describes a new model named electromotive force-impedance to determine the SOC of battery based on the least squares analysis. Determining the state of charge (SOC) of a battery is an essential in fast charging, it can provide parameters in fast charging controlling. More recent models determine the state of charge (SOC) by charging and discharging cycles, this process degrades the chemical composition of the battery which is non-reversible demage to battery, then result in shortening batteries´ life. The proposed model can overcome above disadvantage, firstly analyses the relation between SOC and electrolyte consistency, and then finds out and adopts the relation between the external parameters (such as voltage,current,temperature) and the SOC, finally establishs a model and identifies parameters based on the least squares analysis, so it no need to charge or discharg and avoids the demage to the battery. The new approach is fully validated by compared with results obtained by experiment on lead-acid batteries.