METHOD AND APPARATUS FOR MONITORING AND DIAGNOSING ELECTROCHEMICAL DEVICES BASED ON AUTOMATIC ELECTROCHEMICAL IMPEDANCE IDENTIFICATION

Method for determining the state of an electrochemical device by means of electrochemical impedance spectroscopy (EIS) and equivalent circuit model (ECM) comprising the steps of measuring the system impedance by any EIS device, modeling the measured impedance by an ECM, identifying the ECM parameters through an automatic minimization algorithm, and processing the ECM parameters values to simulate the electrochemical impedance of the device. In particular, the identifications of the number of parameters (i.e. the ECM model components) and of suitable starting values of these parameters are automatically detected through a geometrical pre-analysis of the shape of the measured impedance spectrum Z', which geometrical pre-analysis will be also called in the following as Geometrical First Guess (GFG) algorithm.