Battery thermal management using heavy fuels: An approach to lightweight diesel fuelled hybrid electric vehicles

Lithium-Ion Batteries (LIBs) experience heat generation during charge and discharge, leading to high temperatures, capacity loss, thermal runaway, and material degradation. Battery Thermal Management Systems (BTMS) are crucial for maintaining optimal LIB performance and longevity. This study explores the use of dielectric fuel components as alternative BTMS coolants in diesel/battery-powered hybrid electric vehicles (HEVs). The 1P3S LIB module and BTMS are designed using CATIA. The BTMS Computational Fluid Dynamics (CFD) modelling is conducted using ANSYS-Fluent. Two coolants, air and 3M-Novec 7200, are compared with alternative dielectric fuels based on the EU standard diesel fuel composition. The study evaluates the BTMS performance under varying inlet velocities (0.1–1 m/s) and battery discharge rates (1 C to 2 C). Results show that air is insufficient for maintaining the LIB pack operational temperature (20°C to 45°C). The alternative fuels, particularly n-decane, perform well and similarly to 3M-Novec 7200 in cooling efficiency, keeping the battery pack within optimal temperature ranges and minimizing temperature differences (≤0.5°C). Additionally, these fuels have lower densities than 3M-Novec 7200, offering potential weight reduction (up to 50 kg) while improving cooling efficiency.