Numerical simulation of lithium-ion batteries (LIB) has become extremely vital in the understanding of thermal behaviour of LIBs to develop active and passive battery thermal management systems. The LIB is popular in consumer electronics. Beyond consumer electronics, the LIB is also growing in popularity for the automotive applications such as hybrid electric vehicles (HEVs) and battery electric vehicles (BEVs) due to its high energy density, high voltage, and low self-discharge rate. High amount of heat generally gets developed during charge and discharge of LIB based on the c-rate at which it is being discharged or charged. Hence, there should be a mechanism to understand the thermal behaviour of these cells. Thus, in this paper a numerical procedure has been developed to model electrochemical-thermal behaviour of commercially available 21700 Li-ion cells. NewmanP2D approach is used to arrive at electrochemistry performance of Li-ion cell and pack. Well known commercial code Ansys Fluent is used to derive performance parameters of Li-ion cell and pack. Firstly, a discharge/charge profile is evaluated for NMC chemistry of 21700 cells for various c-rate conditions. c-rates used in this study varies from 0.2c to 1c for which numerical parameters such as Temperature, Heat Source, Voltage and Current densities are evaluated. Ambient temperature considered in this study is 27deg C. This evaluation is then extended to study performance of pack (16S8P pack) w.r.t 1c-rate discharge-charge condition thus replicating fast charge technology.
Results got from this simulation approach helps in understanding thermal performance of pack for the above-mentioned c-rate and ambient condition, thus help overall product design phase of an electric vehicle. Thus, this methodology helps analyse different battery packs with different configuration in achieving better cooling strategy based on its numerical thermal performance.