Thermal Management Analysis in High Voltage Junction Boxes of Electric Trucks

Sammanfattning

As Sweden aims its goals to achieve net zero emissions of green house gases by 2045,the transport sector is accountable for a crucial share of the emissions. For several decades, Sweden has already established electric cars. Through out the time, electric buses, trucks and other heavy-duty vehicle are deliberately being placed to function allaround Sweden. With the increase of battery electric trucks operating in Sweden, the need of having a reliable vehicle charging technology is growing equally. Optimizing the charging infrastructure involves efficient power management coupled with minimizing the production costs of electrical components within the vehicle. This thesis delivers a comprehensive thermal management analysis of high-voltage junction boxes in battery electric trucks with a focus on optimizing several cooling strategies for the busbars operated under a steady-state condition. The evaluation is done for three contrasting thermal designs: Model A using only natural convection method, Model B using passive cooling methods with extruded aluminum fins on the box and Model Cusing forced-air cooling method with integrated fans. In addition to the cooling method comparison, each model is is computed across five busbar thicknesses, ranging from 5 mm to 9 mm. The purpose behind thickness variety is to investigate the impact of conductor size on thermal behavior.All the different configuration performed a thermal simulation using ANSYS Fluent. They are then evaluated using key performance indicators including average and maximum temperatures, surface heat flux, thermal resistance, andsystem cost. The results indicate that Model C achieves the lowest operating temperatures and most stable thermal gradients but suffers with the highest manufacturing and integration costs. Whereas, Model B developed a balanced performance that offers a combination of good thermal behaviour with a better cost-effectiveness and system simplicity. All varieties of thermal improvements lessen after thickness of 7 mm. A thorough framework was formed by integrating a weighted scoring method to identify the most advantageous out of these factors: thermal performance, thermal resistance, cost, and system weight. The investigation offers Model B with a 5 mm busbar as the most practical and thermally efficient design. The results featured that Model B has a good balance of trade-offs between cooling performance and overall system’s manufacture. This thesis provides designin sights for thermally stable, cost-efficient high-voltage junction boxes, with sustainability consideration that support a scalable and reliable electric vehicle architecture.