Novel Loop Heat Pipe System for EV Thermal Management of Batteries: Effects of Ambient Temperatures

Abstract

Building from previous successful results from the Authors, a Loop Heat Pipe (LHP) based Battery Thermal Management System (BTMS) is investigated over a range of different ambient temperatures (from 20°C to 50°C), using a state-of-the-art environmental chamber. LHPs act as thermal vector from the bottom of the battery pack to a remote chiller, while graphite sheets allow to achieve a satisfactory level of temperature homogenization of the cells surface, with low added weight. This design was developed aiming to improve on fast charge timings, all-electric range, reduce costs and complexity, and decrease maintenance requirements. Preliminary studies showed the potential of this innovative BTMS to give better performances than standard active counterparts. The aim of this work is to extend the investigation towards a practical application, by matching experimental results obtained in the environmental chamber with a validated numerical Lumped Parameter Model and extend the results database to different geometries and material/fluid configurations, to support the adoption of this technology by automotive manufactures. Results showed a successful validation campaign, with average temperature discrepancy between the experimental results and the numerical prediction of 0.4°C. Further simulations results demonstrated how the proposed BTMS performs efficiently at higher temperatures, limiting cells maximum temperatures below 60°C even at ambient temperatures of 50°C, increasing safety.