Battery disconnect unit (BDU) high voltage connection units thermal analysis

Since 2015, many governments have started encouraging the adoption of electric vehicles as part of their efforts to reduce gas emissions. After 2030, electric vehicle sales are expected to exceed 30 million units. The rapid development of battery technologies, the most critical unit of an electric vehicle, plays a major role in the spread of electric vehicles. Electrical failures caused by high-voltage batteries can cause serious damage. The Battery Disconnect Unit (BDU) is responsible for disconnecting the circuit in case of excess current, accident, battery charging failure and electricity leakage. Therefore, the thermal analysis of the Battery Disconnect Unit enables safer and more compact designs to be made and tested in a short time. This study includes a thermal simulation of the Battery Disconnect Unit in electric vehicle batteries and the busbars inside the unit. The Unit project is a test device development project conducted by FEV Turkey. This model was subjected to thermal analysis in the ANSYS using a license belongs to Doğuş Üniversitesi. The prototype has been tested in a laboratory by a global cell manufacturer based in Turkey. The project target of the Battery Current Disconnect Unit was at least 5 minutes under 400A current, which was implemented for 8 minutes in experimental tests. The results of the thermal simulation were compared with the temperatures obtained from experimental tests. The 24 condition were created and each condition applied variable ambient temperature and convection heat transfer coefficient. The effect of convection transfer coefficient on temperature and the effect of ambient temperature on this coefficient has been studied. The error rate between simulation data compared with experimental data was between 0.10%-5.62%. The theoretical information compared to the busbars in the Unit was observed in the simulation. As a result, this thesis examined the thermal performance of the Battery Disconenct Unit by studying the effects of the convection heat transfer coefficient and the changes in the cross sections and lengths of the busbars. The study is expected to contribute to the further advancement of electric vehicle technology.