Evaluation of Parameter Variations of Equivalent Circuit Model of Lithium-ion Battery under Different SOH Conditions
Zhiyong Xia, Jaber A. Abu Qahouq
Abstract
This paper studies the patterns of equivalent circuit model (ECM) parameter variations under different state-of-health (SOH) conditions for lithium-ion battery. An ECM is constructed in this paper to characterize the ageing behavior of battery by fitting ECM to experimentally measured EIS data within the frequency range from 0.01 Hz to 7.928 kHz. The experimentally measured EIS and SOH data are obtained from an accelerated ageing experiment of lithium-ion battery conducted in the laboratory. The comparison between the EIS data generated from the constructed ECM and experimentally measured EIS data validates the constructed ECM. The variations of the parameters of the ECM as a function of the changes in the SOH of the battery showed that as the battery's health deteriorates overtime, the value of series resistor of the ECM increases and the values of the capacitance components of CPE of the ECM decrease. The presented model and its results can provide a way to estimate or co-estimate the SOH of the battery.