Modeling the Effect of Aging on the Performance Decay of a Lithium-Ion Battery during Charge-Discharge Cycling

Abstract

The lithium-ion battery (LIB) is the primary choice for electric vehicle (EV) applications due to its high energy density, high voltage and low self-discharge rate. The service life of LIB for EV applications is generally limited by aging and the aging of LIB depends strongly on the thermal history during usage. In order to secure the resilience of LIB for the EV applications, it is essential to develop a modelling tool that has a capability to account for the relationship between the aging and thermal history of LIB to design an optimal battery management system. In this work, a modeling is performed to predict the effect of aging on the performance decay an LIB as well as variation of thermal behaviours during cycling for a long time. The validation of the modeling approach is provided through the comparison of the modeling results for a 14.6Ah LIB cell from LG Chem. with the experimental measurement data obtained from the cycling tests. The cycling tests were performed under the protocol of the constant-current charge and the constant-current discharge. In Fig. 1, the discharge capacities measured at every thousand cycles for discharge rates of 1C, 3C, and 5C were compared with those calculated from the modeling. The modeling results and the experimental data on the capacity fade of the aged LIB cell are in good agreement in Fig. 1. Fig. 2 shows the temperature distributions from the experimental IR image and the modeling for the LIB at an environmental temperature of 25 ˚C at times of 240, 480, and 636 s during the CC discharge with a rate of 5C after 1000 cycles. Model predictions reasonably reproduce the experimental data. Figure 1