Transient Thermal Evaluation of Electric Vehicle Batteries Based on Different Vehicle Driving Cycles

Abstract

Abstract. Adoption of electric vehicles (EVs) has become imperative to combat the climate change issue with fossil fuel-run vehicles. With the growing market of EVs, lithium-ion batteries have become widespread, despite challenges such as overheating, uneven heat distribution, and thermal runaway risks. Effective thermal management is paramount to ensure efficiency, safety, and longevity. The transient thermal performance is examined for a Panasonic NCR-18650PF battery pack integrated into a drivetrain model based on the 2018 Nissan Leaf. For simulating real-driving conditions, the model uses standard drive cycles to determine motor torque and phase voltages. The EV model is on a simulink platform. Battery power data were then used in ansys fluent to evaluate the effectiveness of phase change materials (PCMs) in improving thermal management under dynamic load conditions. On a trial basis, a 20-cell battery pack was designed with two configurations—20S (20 in series) and 10S2P (10 series in 2 parallel)—for thermal analysis in ansys using multi-scale multi-domain and Newman, Tiedemann, Gu, and Kim models. A 3 mm layer of three PCMs (n-octadecane, RT 35, and RT 44 HC) was applied around the cylindrical cells. It is shown that RT 44 HC reduced temperatures by 12.21 K (New European Driving Cycle (NEDC)) and 38.32 K (Worldwide Harmonized Light Vehicles Test Procedure (WLTP)), demonstrating high effectiveness under dynamic loads. Combined series and parallel configurations yielded similar thermal performance. For the 20S pack, n-octadecane has performed well with a modest increase of 1.4% in peak temperatures for WLTP Class 3 and NEDC. With safer and economical thermal management, the United Nations Organization’s sustainable development goals can be effectively addressed.