Heat transfer optimization of winged-wavy rib cooling channels for LiFePO4 battery thermal management

Abstract

Effective thermal management is essential for maintaining the safety, durability, and performance of lithium-ion batteries. In this study, the heat transfer performance of a rib-enhanced cooling channel was experimentally investigated and subsequently applied to the thermal management of LiFePO4 battery cells. A series of winged-wavy rib configurations with different inclination angles (30°, 45°, 60°, 75°, and 90°) was installed on the heated wall of a square cooling channel to examine their influence on flow structure, heat transfer enhancement, and pressure loss. Experiments were conducted under turbulent flow conditions with Reynolds numbers ranging from 10,000 to 30,000. The results show that introducing wing elements on the wavy ribs generates secondary flows and longitudinal vortices, thereby enhancing fluid mixing and disrupting the thermal boundary layer near the heated surface. Compared with the conventional wavy rib configuration, the normalized average Nusselt number increased by 16.1%, 21.7%, 24.2%, 23.3%, and 13.7% for rib inclination angles of 30°, 45°, 60°, 75°, and 90°, respectively. Although the rib structures increased the friction factor by approximately 53–64%, the 60° winged-wavy rib configuration exhibited the best thermo–hydraulic performance, with a thermal performance factor approximately 5.7% higher than that of the baseline case. Compared with previously reported rib-grooved and vortex-promoting passive enhancement configurations, the proposed winged–wavy rib combines periodic flow acceleration with longitudinal vortex generation, enabling effective near-wall mixing and thermal boundary-layer disruption for air-cooled battery thermal management applications. To evaluate practical applicability, the optimized rib configuration was implemented in a battery thermal management system for LiFePO4 cells operating at charge–discharge rates of 0.4C–0.6C. The rib-assisted cooling channel reduced both the local and average surface temperatures and maintained the temperature difference among cells within approximately 1–2 °C, indicating improved temperature uniformity within the battery module. These results demonstrate that the proposed winged-wavy rib structure can enhance convective heat transfer and provide an effective passive cooling approach for lithium-ion battery thermal management systems.