Optimization design of flow path arrangement and channel structure for lithium-ion battery cooling plate based on the three-field synergy principle

• The synergy mechanism of the three fields in the cooling plates was analyzed. • Three key rules for cooling plate flow path design were summarized. • A new cooling plate with a shark-skin bionic riblet channel structure was designed. • The mechanisms of performance improvement were elucidated. Cooling plate is the key heat transfer component for the current thermal management system of power battery. To enhance its comprehensive performance, this study numerically analyzed the mechanism between the temperature, pressure, and velocity fields of coolant within the flow channels guided by the three-field synergy principle. It was found that the development of the thermal boundary layer in the straight channel and the flow separation in the curved channel were the primary factors for the deterioration of the heat transfer and flow resistance performance in the original cooling plate. The flow channel arrangement was optimized considering practical engineering constraints, and three fundamental principles that should be upheld for the flow path arrangement of a high-efficiency, low-resistance cooling plate were encapsulated. Based on this arrangement, a shark-skin bionic riblet channel structure cooling plate was proposed. The results indicate that the bionic cooling plate can improve the synergy among the three fields. Compared to the original cooling plate, the bionic cooling plate exhibits an increase in Nusselt number by 7.22–8.55 % and a decrease in friction coefficient by 22.32–23.21 % at equivalent Reynolds numbers, leading to an overall performance improvement of up to 19.69 %. Furthermore, comparative experiments were conducted. It was found that the bionic cooling plate could reduce the temperature of the simulated battery heat source by up to 2.9 °C compared to the original cooling plate while also reducing the pressure drop by up to 3.0 kPa under the same conditions. This paper can provide guidance on cooling plate design for high-performance and energy-sensitive battery thermal management systems.