Combining the Distribution of Relaxation Times from EIS and Time-Domain Data for Parameterizing Equivalent Circuit Models of Lithium-Ion Batteries

Equivalent circuit models (ECMs) are a widely used modeling approach for lithium-ion batteries in engineering applications. The RC elements, which display the dynamic loss processes of cell, usually parameterized by fitting ECM to experimental data either time-domain or frequency-domain. However, both types have limitations with regard observable time constants electrochemical processes. This work proposes method combine and frequency-domain measurement parameterization elements exploiting full potential distribution relaxation times (DRT). Instead using only partial information from DRT supplement conventional algorithm, we determine parameters an arbitrary number directly DRT. difficulties automated deconvolution DRT, including regularization choice optimal factor, is tackled L-curve criterion optimized calculation via Tikhonov regularization. Three different approaches merge time- presented, novel where simultaneously calculated impedance spectoscropy (EIS) pulse measurements. model commercial 18650 NCA cell was validated during validation cycle consisting constant current real-world automotive cycling yields relative improvement over 40% compared EIS-fitting algorithm.