Probing the cooling effectiveness of phase change materials on lithium-ion battery thermal response under overcharge condition

Abstract

Usage of phase change materials (PCM) can help reduce the safety risk during LIB operation. This work investigates the cooling effectiveness of PCM on lithium ion battery operation under overcharge scenario. Combined with adiabatic overcharge tests at 0.1, 0.2, 0.5, 1, 2 current rates (C-rate), the relationship of cell thermal performance and cooling efficacy with C-rates, thermal contact resistance, amount and melting temperature of PCM are analyzed by lumped model. Results indicate steep decline of cooling effectiveness with C-rate increase. Temperature difference between cell and PCM is stable below 1C, however, abrupt hikes are observed at higher C-rates. Effectiveness increase with PCM thickness is also seen up to a critical thickness of 3 mm beyond which minimal change is observed while thermal contact resistance is found to enlarge the temperature difference between cell and PCM during the melting process causing wide variability in cooling effectiveness magnitude. For similar latent heat and density material, low melting temperature PCM exhibits superior cooling characteristics as compared to its high temperature counterpart. The results contribute to enhanced understanding of the thermal performance of PCM and LIB during overcharge process under varying conditions.