Thermal assessment of Li-ion batteries incorporating phase change materials using a new 2D model

This paper presents a novel physical model to analyse the energy efficiency of a thermal management system based on a phase change material (PCM) for Li-ion batteries including diffusion and irreversible phenomena such as entropy. Real-world battery performance was assessed using the New European Driving Cycle (NEDC), which includes four urban routes and one ultra-urban route. The model's accuracy was validated against experimental data, and an in-depth analysis of various parameters was conducted. The results show that the choice of PCM melting temperature range is pivotal in the battery thermal management system (BTMS) performance, with RT-28HC and RT-31 exhibiting superior thermal regulation during the three charge and discharge cycles. Although the thermal gradient within the pack is often negligible under different ambient conditions, higher ambient temperatures (40 °C) or high convective coefficients (60 W/m2K) increased thermal gradients. Simulations reveal that combining PCM and active cooling systems is required to reduce thermal gradients and maintain temperature uniformity, especially in extreme conditions and long operating times. This new model provides a cost-effective, agile alternative to computationally intensive methods for analysing dynamic thermal behaviour during long charge and discharge cycles.