| abstract |
An internal impedance diagnostic system for an energy storage device is disclosed. A method of estimating cell impedance parameters from an impedance equivalent circuit model (ECM) includes the steps of applying or detecting a time-varying current signal through a cell, measuring voltage and current variations, applying an adaptive filter on the sampled data to identify the m-order transfer function for the measured system, constructing a set of simultaneous equations, extracting individual impedance parameter values from the equations, running diagnostic tests and algorithms to analyse the change in cell impedance values and computing accurate cell related estimation parameters and conditions. The energy storage device may be an electrochemical cell. |