Battery thermal management system for electric vehicle using heat pipes

Thermal management of battery systems in electric vehicles is critical for maintaining energy storage capacity, driving range, cell longevity and system safety. In this paper, heat pipe based thermal management system for high power battery, with eight prismatic cells, has been proposed, designed and tested for heat load up to 400 W. The heat pipe system consists of two parts: heat pipe cooling plates to extract heat from the individual prismatic cells of the battery module, and remote heat transfer heat pipes to transport heat from the module to liquid cooled cold plates located 300 mm away. As compared to a conventional liquid cooled system, two-phase heat pipe based thermal control will provide better cell/module temperature uniformity, less complicated design and a safer system (no leakage issues in high voltage areas). Modeling of the complete system was done based on two-phase analysis for the heat pipe portion, and single phase analysis for the cold plate portion. The system manufacturing and evaluation method has been covered in detail. Based on controlled experimentation using a dummy battery module, it was estimated that the proposed system is able to successfully dissipate 50 W heat load from each cell while keeping their temperature below the given 55 °C limit using water coolant with a 25 °C inlet temperature and 1 lit/min flow rate.