Optimization of the double-sinusoidal manifold cold plate structure for power battery thermal management

Proper thermal management plays a crucial role in ensuring the safe operation and long-term performance of lithium-ion batteries (LIBs). Conventional parallel-flow cold plates are prone to uneven temperature distribution within the LIB module because of non-uniform coolant distribution. A double-sinusoidal manifold cold plate (DSM-CP) was proposed for a prismatic LIB module through the joint regulation of coolant splitting at the inlet and coolant merging at the outlet to improve flow uniformity and temperature uniformity.. Based on the validated thermal model of LIBs, the thermal and flow performance of the basic parallel-flow cold plate (BP-CP), sinusoidal inlet manifold cold plate (SIM-CP), and DSM-CP were compared under 2.5C discharge rate. An orthogonal design was adopted to examine the influence of mass flow rate ( M ), sinusoidal amplitude ( A ), tilt angle ( α ), and angular frequency ( w ) on maximum temperature ( T max ), maximum temperature difference (Δ T ), and energy loss ( W ) of the DSM-CP. The DSM-CP was optimized using the non-dominated sorting genetic algorithm-II (NSGA-II) based on the fitting equations constructed by the response surface method. Results indicate that the parameter-optimized DSM cold plate(DSM-OCP) maintains excellent thermal performance ( T max = 34.50 °C, Δ T = 4.05 °C) with a significant 19.7% reduction in W compared to the DSM-CP. Compared to the BP-CP, Δ T and the flow non-uniformity index ( S ) decreased by 16.5% and 58.8%, respectively. Finally, the DSM-OCP was experimentally validated. The maximum absolute errors of T max and Δ T were 0.31 °C and 0.41 °C, respectively, while the maximum relative error of Δ P was 3.41%, confirming the effectiveness of optimization.