Calibration of EIS analyzers using reference impedances

The electrochemical impedance spectroscopy (EIS) is used to estimate the state of charge and the state of health of batteries made from lithiumion cells. A calibration traceable to SI units of such instruments is up to now possible only to a very limited extend. However, such calibration is essential in order to ensure comparable measurement results for a reliable battery diagnosis. To meet this demand, a prototype of a reference impedance was realized using electronic components. Also a calibration procedure has been developed, that can be carried out using only the standard equipment of a calibration laboratory for AC quantities.