Multi-Objective Optimization with PCM integration and delayed cooling strategy for high-rate discharge applications

Abstract

The thermal safety of lithium-ion batteries has been a significant concern in the industry, prompting a pressing need for research to ensure efficient and energy-saving operation of energy storage battery's thermal management system. This study focuses on addressing the multi-objective optimization problem of heat dissipation coupling energy consumption in battery packs under high discharge rate with a maximum temperature (Tmax), a maximum temperature difference (ΔT) and the pump energy consumption (P) as objectives. The Kriging interpolation and CRITIC weighting method are used for multi-objective optimization to determine the optimum solution objectively. The results indicate that increasing the diameter of the liquid cooling pipe (X) and the coolant inlet velocity (vin) both contribute to reducing the maximum temperature of system. However, these changes have negative impacts on temperature uniformity within the battery pack and the energy consumption of the water pump. The above rule is reversed when considering the impact of initiation time of coolant flow (T), which in addition can lead to exhaustion of latent heat of CPCM and insufficient cooling capacity and thus potential overheating of the battery pack. According to the CRITIC weighting method analysis, the index weights of Tmax, ΔT and P are 40.21%, 32.01% and 27.79%, respectively. Further analysis reveals that the optimal comprehensive performance of the battery pack thermal management system is achieved when X = 3.875 mm, vin = 0.4 m/s, and T = 537.5 s, corresponding the P of 2.53 J, Tmax of 309.32 K and ΔT of 2.41 K, both falling within the specified technical requirements at a discharge of 4 C . The latent heat of the phase change material in the battery pack has been recovered at this stage, providing sufficient cooling capacity for the next cycle of charging and discharging.