Novel Approach to Characterize Li-ion Battery Cells for the Purpose of Battery Emulation by Fitting of the Isolated Cell Dynamics

Abstract:
Electric equivalent circuit models are a common method to represent the dynamic behavior of a battery cell. For this purpose, the cells are electrically excited and the system response is measured. An equivalent circuit is then parameterized in such a way that the behavior of the model corresponds to that of the cell. This paper presents a novel method to simplify the fitting and parameterization process, while increasing the accuracy of the model. This can be achieved by limiting the fitting process to the dynamic part of the cell behavior. The results of the equivalent circuit models parameterized this way are verified using additional measurements performed on a different battery cell. The parameterized models can then aid, for instance, in the design of battery emulators.