Distribution of relaxation times for effect identification and modeling of impedance spectra

Impedance spectroscopy provides an increased amount of information with one measurement. The drawback is that a suitable model as well as a reliable fitting is needed for data evaluation. Therfore a suitable data representation is needed that serves two purposes. First it should help to identify processes within the device under test as a support for building a model and it should give some initial values for parameterization. The distribution of relaxation times (DRT) provides such a data representation. It transforms impedance data from the frequency domain to a time constant domain were different relaxation mechanisms can be separated more easily and sometimes their type can be identified using the shape of the DRT. In an example the DRT is used to identify mechanisms and to build a suitable model for the impedance data analysis of battery aging data.