Analysis and optimization of thermal management system for super elliptic battery cell geometry in electric vehicles

Abstract

Battery technology is the most important parameter affecting the range of electric vehicles. One of the biggest concerns in battery systems developed for electric vehicles is in particular, the temperature in the cells of lithium-ion (li-ion) batteries allows a limited degree of variation (°C) within the entire battery pack. Therefore, today’s electric vehicle research and development studies are focused on this issue. In this study, the battery systems of electric vehicles are parametrically designed with a 3D solid modeling program according to the super ellipse geometry, which offers a wide range of geometries, and the thermal management of the battery systems is realized. TM studies were done in ANSYS CFX. Air was selected as the coolant and the effect of different parameters (cell geometry, inter-cell distance, cell height, heat flux, inlet air velocity, and inlet air temperature) on the battery cell temperature was analyzed. D-Optimal experiment design was created with MATLAB. A two-alternative optimization study was carried out as constrained function local optimization and genetic algorithm optimization. Accordingly, it was observed that the battery pack gives the best thermal result when the distance between the cells increases and the inlet air temperature decreases. In addition, when the most well-known envelope type, cylindrical and rectangular prism shaped battery geometries in the literature are evaluated, it is concluded that the most ideal result is closer to the envelope type geometry.