Design and experimental investigation of air-cooled battery thermal management system for electric vehicles

With the reduction of environmental pollution and protection of the environment, the biggest problems of climate change are tried to be alleviated. 23% of environmental pollution belongs to the automotive industry and the automotive industry carries out this pollution caused by internal combustion engines. For this reason, both automotive manufacturers and scientists are making great efforts to develop electric vehicles (EA) and hybrid electric vehicles (HEA) in order to get rid of harmful emissions. The battery pack is the most important component of electric vehicles and hybrid electric vehicles. While some or all of the hybrid electric vehicles are powered by electricity, electric vehicles are completely powered by the battery pack. Lithium-ion batteries, which have high energy and power density, are widely used because of their long life and environmental friendliness. However, the decrease in performance at low and high temperatures, the depletion of the durability and life of the battery cells, and the safety risks caused by thermal leaks necessitate the battery thermal management system for the battery pack. In this thesis, the battery pack consisting of 18 lithium-ion battery cells in a cylindrical structure and three different models (the model with the back and sides open, the model with the back side open, the sides closed, and the model with the back side closed and the sides open) are used. The cooled battery box is designed and manufactured. With this manufactured structure, cooling experiments of the air-cooled battery thermal management system were carried out. In the experiments where the fan was used at two different speeds (1,088 m^3/min and 0.812 m^3/min), the temperature values of the battery pack in charge and discharge conditions were examined. The portable design of the air holes in the design of the battery box enabled different models to be combined in a single battery box. In the experiments carried out in 25 room conditions; The increase in air flow rate increased the temperature distribution of the battery pack to be more homogeneous, and the increase in the air intake area increased the cooling performance. It has been observed that the battery cells in the middle of the battery pack get hotter. In addition, the linearity of the air flow has ensured a more homogeneous temperature distribution in the battery pack. With this study, it is aimed to contribute to the studies in the field of air-cooled battery thermal management system.