A review on thermal management performance enhancement of phase change materials for vehicle lithium-ion batteries

Phase change materials (PCMs) have been proposed to manage the temperature of lithium-ion batteries in new energy vehicles, sharing the merits of low energy consumption, high temperature uniformity and affordable price. The low heat extraction rate as to low PCM thermal conductivity and the limited thermal storage capacity are the two major flaws of PCM-based battery thermal management systems. To fix these two flaws, three enhancement strategies (and corresponding specific measures) have been developed, which are increasing heat extraction rate (increasing PCM thermal conductivity and extending heat transfer area), recovering thermal storage capacity (coupling PCM with other cooling techniques) and reducing PCM cooling load (hybridizing PCM with other cooling techniques). In this review paper, the reinforcement principle of these measures was illustrated firstly. Following that, the advancement of each measure was reviewed comprehensively. With enhancement strategies, the thermal management performance has been improved considerably, demonstrating the feasibility and potential of PCM-based systems. No commercial vehicles, however, have adopted this type of system. Finally, a research roadmap from material level, to cell level and to system level was refined and eight research directions were proposed. In summary, a string of problems still need to be solved and efforts should be poured into sustainedly for the commercialization of PCM-based systems. • Differentiated and reviewed three enhancement strategies for PCM-BTMSs. • Excessively enhancing PCM thermal conductivity may deteriorate battery performance. • Thermal management performance of hybridized systems is superior to coupled systems. • Refined a research roadmap and developed eight potential research directions. • Superior performance is presented for gradient filling or arranging strategies.