Figure shows the fitted parameters R ZARC , τ ZARC and ϕ ZARC of the three ZARC elements for different SOC values of the Li-ion button cell with and without use of DRT. The resistance of ZARC elements shows less extreme values, fluctuations and outliers in the fits performed with DRT information. The parameter τ ZARC represents the inverse frequency of each ZARC semicircle in the EIS spectrum. According to the DRT spectrum, the three ZARC elements have distinct positions with little overlap, as is observed in Figure . Purely numerical parameter estimation without DRT information, on the other hand, exhibits overlap of fitted ZARC elements at higher SOC (Figure ). Fitting of ϕ ZARC using DRT information shows fairly small, smooth variations as a function of SOC. By unconstrained numerical fitting, the resulting values of ϕ ZARC strongly fluctuate, which appears difficult to justify for a fresh battery. Furthermore, values of ϕ ZARC are occasionally higher than 1 if no constraints for the fitted parameter are applied.