Global sensitivity analysis of battery equivalent circuit model parameters

TL;DR

This study applies the Morris method to perform global sensitivity analysis on a lithium-ion battery equivalent circuit model, identifying parameters that can be fixed without affecting voltage output accuracy.

Contribution

It introduces a comprehensive sensitivity analysis of ECM parameters across SOC ranges, highlighting which parameters are critical and which can be simplified.

Findings

Certain parameters have negligible impact on voltage output.

Parameters vary with SOC but some can be fixed.

Experimental validation confirms the analysis.

Abstract

This paper considers one of the most commonly used equivalent circuit models (ECMs) for lithium-ion batteries and investigates the sensitivity of the model output to changes of model parameters using the Morris method. Experiments are carried out on a lithium-ion cell with nickel manganese cobalt oxide (NMC) electrode and parameters of the model are identified in the state of charge (SOC) range [100%,10%]. Although all the model parameters do vary with SOC, global sensitivity analysis reveals that the uncertainties of some of the parameters generate very little uncertainty in the voltage output, implying that those parameters can be taken as constants without compromising the accuracy of the model. This is further confirmed by experimental validation.