Patent ID: 8849598

Claim:
A method of estimating an internal state of at least a first electrochemical system for electrical power storage, wherein at least one property relative to the internal state of the first electrochemical system is estimated from electrochemical impedance measurements, comprising: carrying out testing in a laboratory of differing internal states of at least a second electrochemical system of a same type as the first electrochemical system by measuring the at least one property relative to the internal state of the second system and measuring the electrochemical impedance of the second electrochemical system at least at one frequency; defining an electrochemical impedance model in a computer programmed with software, which when executed, provides the electrochemical impedance model as a function of the at least one property and of parameters, and calibrating the parameters by an adjustment of the electrochemical impedance measurements obtained for the internal states; determining an electrochemical impedance Z of the at least the first electrochemical system for at least one frequency, and estimating the internal state of the at least the first electrochemical system by estimating the property relative to the internal state of the second electrochemical system using the model and the electrochemical impedance Z.