Patent ID: 6876174

Claim:
A method for a dynamic measurement of the state of health and charge of a vehicle battery, based on the measure of sinusoidal voltage increase ΔV=V max sine(2πft) when a sinusoidal current, ΔI=I max sine(2πft+φ) is added to the normal charge and discharge current of the battery, where f is the frequency and I max , the amplitude of the superimposed sinusoidal current, by whose magnitudes the electrochemical impedance of the battery Z(f)=V max /I max e jφ is calculated, characterised on comprising the following stages: Application of a first sinusoidal current signal of a prefixed frequency to the battery terminals, generating a voltage response in said terminals as an alternate voltage component superimposed over the direct current, together with other alternate voltage components generated by different electric and electronic devices supplied by said battery and/or connected to it; elimination of the continuous component of the response signal leaving only the alternate voltage components; application of a second high precision voltage signal, for reference, having an identical frequency to that of the mentioned first sinusoidal current signal and execution of a synchronous detection of the alternate voltage component generated by the application to the battery terminals of that first sinusoidal current signal to only obtain a voltage proportional (modulus and phase) to the electrochemical impedance of the battery, and evaluation as from said electrochemical impedance value, at any moment of battery operation in the vehicle, of the state of health and state of charge of the battery, by comparing with modulus/frequency diagrams pre-analysed and stored in memory for different types of battery.