Thermal Performance Evaluation of 45° Ribbed and Dome-Enhanced Serpentine Cold Plates for Battery Thermal Management under Laminar Flow Conditions

Abstract

Thermal management of lithium-ion batteries is critical to ensure operational safety, electrochemical stability, and lifecycle performance in electric vehicles. Under laminar flow conditions typical of battery cooling systems, smooth serpentine cold plates often exhibit limited convective heat-transfer performance. In this study, a three-dimensional, steady-state numerical investigation was conducted to evaluate the effectiveness of 45° rib- and dome-based passive enhancement strategies in improving thermal performance. Serpentine cold plates incorporating triangular, trapezoidal, semi-circular ribs, and dome structures were analysed under a uniform heat flux of 30,000 W/m² applied to the bottom surface of a copper plate, while the top surface was maintained adiabatic. Water at 21°C was used as the coolant, and simulations were performed for Reynolds numbers ranging from 200 to 1000 under laminar flow conditions. Thermal performance was quantified using the Nusselt number, convective heat transfer coefficient, and convective thermal resistance. Results indicate that all enhanced geometries improved heat transfer relative to the smooth channel, particularly beyond Re = 400. At Re = 1000, the semi-circular rib configuration achieved a maximum Nusselt number of 44.85 compared to 26 for the smooth case, corresponding to a 72.5% enhancement. The convective heat transfer coefficient increased from 2733 to 4713 W/m²K, while convective thermal resistance decreased by approximately 41.8%. These findings confirm that 45° rib-induced flow disturbance significantly enhances convective heat transfer under laminar conditions, with semi-circular ribs providing the most effective passive thermal enhancement for high-performance battery thermal management systems.