Optimal design of lithium ion battery thermal management systems based on phase change material at high current and high environmental temperature

The market of electric storage systems is widely dominated by Lithium ion batteries, whose peculiarity is the need for a thermal management system, whose proper design is complicated by the interaction. among different design and operating parameters. A specific methodology for carrying out the task is still lacking. In this context, the present paper proposes a systematic framework for the design of passive and hybrid thermal management systems (TMSs) of Li-ion batteries. Thermal tests were carried out on Lithium-Titanate-Oxide cells under realistic operating conditions in a controlled environment to characterize the electrical and thermal behaviour. A thermofluid dynamics model of the battery was implemented in COMSOL Multiphysics. The experimentally validated model was used to evaluate the influence of different design and operating parameters (ambient temperature, charge/discharge current, phase change material thickness and melting temperature) using the Taguchi method (orthogonal arrays), and discussing inter-related effects of the studied parameters via interaction plots. Air temperature (45°C) and/or discharge current (69–92 A) were identified as critical operating conditions beyond which thermal runaway issues occur. Starting from the optimal design conditions for a passive TMS, the same methodology was used to assess a hybrid PCM-liquid cooling system as an alternative configuration. The results indicate that, compared to the baseline case of natural cooling, the optimal designs of standalone PCM and hybrid cooling system led to a reduction in maximum cell temperature of 11 and 22°C, respectively, showing the high potential of these TMSs.