Master Degree / Yüksek Lisans Tezleri
Permanent URI for this collectionhttps://hdl.handle.net/11147/3008
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Master Thesis Numerical and Experimental Investigation of an Electric Vehicle Battery Module Thermal Management System(Izmir Institute of Technology, 2022) Gediksiz, Çağlar; Çetkin, ErdalToday, electric vehicles play an essential role in preventing pollution from fossil sources. Therefore, it is vital to develop battery technology in electric vehicles. The biggest problem experienced is the thermal runaways, which is a phenomenon that may cause burning and explosions following the decrease in battery capacities. The thermal runaway problem can be solved by using the thermal management system to keep the temperature range under control. In this study, a 6.7 kWh battery pack was produced. Battery pack operation consists of two parts, mechanical and thermal. In the mechanical part, battery pack assembly and drop tests, one of the mechanical tests, were carried out. At the end of the battery pack assembly, voltage measurements were made, and the accuracy of the assembly was demonstrated. Besides, a numerical and experimental study supported drop tests. As a result of this study, the battery case did not show permanent deformation (2.529x 108 N/m2) as suggested in the numerical experiments (1.263x 108 N/m2). Discharge characteristics and battery module model were discussed in the thermal management part. The information in the literature confirmed the discharge characteristic. The gap between the battery cells reached its most efficient value at 8 mm. In the developed battery module, thermal management was attempted using a heat plate and a cooling pipe. According to the numerical results, the battery module reaches 311.37K at 10C discharge. In the experimental process, the battery pack was charged with 15 amps and discharged with 30 amps. Moreover, the temperature values reached a maximum of 31 degrees. In the experiment on electric vehicles, a maximum discharge level of 255 A was observed. In this experiment, the battery pack reached a maximum of 36 degrees.Master Thesis Numerical Investigation of Various Heat Transfer Mechanisms on Thermal Management of a Lithium-Ion Battery Pack(Izmir Institute of Technology, 2022) Şahin, Resul Çağtay; Çetkin, ErdalLithium-ion battery packs are preferred in Electrical and Hybrid Vehicles (EVs and HEVs) due to their efficient and stable energy storage characteristics. Battery Thermal Management Systems (BTMS) have vital importance in EVs and HEVs to keep the batteries in desired temperature range to maximize performance and lifetime. Air cooling is a well-known method with the advantages of being simple and light but main concern for air cooling is effectiveness and pressure drops due to low heat capacity and thermal conductivity of air. This work compared various cooling designs for battery modules based on the surface temperature of batteries and the parasitic power consumption. Modules were built with COMSOL Multiphysics 5.5, and their accuracy was validated by experiments. Each module involves an equal number of batteries whose thermal characteristics were simulated by the electrochemical-thermal battery model, the P3D multiscale model. As a result, the maximum temperature was reduced by 5% (1.8°C) for inline alignment with baffles and 7.2% (2.8°C) for staggered modules, and the temperature gradient was reduced by 40% (1.7°C) for inline and 35% (1.5°C) for staggered alignments. While fan power consumption of inline alignment with triangle baffles (0.98W) was 3.5 times higher than the base design (0.27W), it was 0.23W for staggered design. Moreover, the cooling performance of different winglet parameters was compared and documented.