A comprehensive review on heat pipe based battery thermal management systems

Heat pipes are currently attracting increasing interest in thermal management of Electric vehicle (EV) and Hybrid electric vehicle (HEV) battery packs due to its superconductive capability, robustness, low maintenance and longevity. With the focus of battery thermal management directed towards both convective and conductive cooling, a significant number of research, both experimental and numerical investigations have been performed during the past decade. However, heat pipe based battery thermal management systems (HP-BTMS) are yet to be commercialized due to lack of understanding their limitations during rapid heat fluctuations and adverse environmental conditions, performance under multiple heat loads, failure criteria in the context of battery thermal management and lack of simple and versatile thermal models to accurately predict the battery thermal performance at module and pack level. This comprehensive review highlights the different heat generation mechanisms of Li-ion batteries and their resulting consequences, followed by the operating principles of heat pipes along with background and shortcomings related to heat pipe based battery thermal management, for the mere purpose of further development of this promising thermal management system. Different heat pipe based thermal management systems developed during the last decade along with their modelling approaches, including the methods adopted for enhancing heat transfer are critically analysed. Heat pipes have demonstrated to be an effective approach in maintaining optimum cell surface temperature, however, several areas require attention if this system is to be commercialized. Niche types of heat pipes such as pulsating heat pipes, loop heat pipe, mini/ micro heat pipe have also been reviewed and their advantages, disadvantages, and challenges in the context of BTMS are discussed. Finally, the current status, challenges and prospects of the future direction in HP-BTMS are highlighted.