Numerical Assessment of a Hybrid Nanofluid Concentrations Effects on Heat Transfer Enhancement for Liquid Battery Thermal Management System

Electric vehicles are characterized by high lifetime and efficiency dependence on temperature and, as such, require extra attention to thermal management efficiency and reliability. Nanofluids have emerged as a novel technology for improving the heat transfer characteristics of thermal management systems. This paper numerically investigated the utilization of composite CuO-MgO-TiO2 (60%-30%-10% weight composition) ternary hybrid nanofluid with different concentrations (0.1%, 0.25%, and 0.5%) in a liquid battery thermal management system. The enhancement potential was evaluated based on the maximum temperature and temperature difference as well as a performance factor considering thermal enhancement against the increase of fluid viscosity. The study concluded that the optimum nanofluid concentration is 0.25%, at which the maximum temperature and temperature difference improved by 0.5% and 4.42%, respectively, compared to the base fluid case, producing a performance factor of 0.54. Further increasing the nanofluid concentration (0.5%) produced worse overall performance compared to the 0.25% concentration case.

I. Introduction

Electric Vehicles (EVs) are envisioned to substitute conventional internal combustion engine (ICE) vehicles due to growing concerns related to emissions, global warming, and the depletion of hydrocarbon fuels [1]. There are a number of battery configurations proposed and adopted to store energy in EVs, including aluminum-ion, lithium-ion, lead-acid, sodium-sulfur, and vanadium-based flow batteries [2]. Lithium-ion batteries are the most favorable choice in the EV industry due to their high energy density and efficiency, extended cycle life, and reduced self-discharge rate ([3], [4]). A major issue undermining a wider commercial adoption of lithium-ion batteries is their high lifetime and performance dependence on temperature. The optimum temperature range for best performance is reported to roughly fall between 25 °C and 40 °C, with temperature nonuniformity maintained below 5 °C ([5], [6]). This high temperature dependence emphasizes the importance of a robust thermal management system that ensures an optimum temperature range over a wide range of operating conditions.