Optimization of Stepped Z-type BTMS Plenum by Introducing Chamfer Angle under Driving Conditions of EVs (10–120 km/h)

Thermal management of batteries in electric vehicles (EVs) is crucial for ensuring performance, safety, and longevity. This study presents an optimized design of an air-cooled battery thermal management system (BTMS) to Enhance cooling Efficiency while minimizing pressure drop. The standard Z-type BTMS structure exhibited severe thermal non-uniformity, with heat accumulation in specific battery regions. To address this issue, a stepped plenum structure was introduced, resulting in improved cooling distribution, an 8.2% reduction in temperature deviation, and a lower peak temperature of 56 °C. However, this modification increased the pressure drop by 23.8%. To mitigate this issue, a chamfered step design with inclination angles of 15°, 30°, 60°, and 90° was further analyzed. The results demonstrated that the 30° chamfered step structure consistently Exhibited the best performance across all inlet velocity conditions, achieving a maximum pressure drop reduction of 3.97% at 35 m/s compared to the initial step model. Additionally, the chamfered design maintained a stable temperature distribution across all flow conditions, ensuring effective cooling performance while reducing pressure loss. The optimized BTMS model effectively enhanced heat dissipation, reduced temperature non-uniformity, and minimized pressure loss. These findings contribute to high-performance BTMS designs that improve battery lifespan and EV safety under driving conditions.