Pulsed flow for hybrid thermal management: A multi-objective optimization and performance evaluation

Maintaining lithium-ion batteries within an appropriate temperature range is essential for performance and safety. This study comprehensively investigates the integration of a pulsed flow cooling strategy into a hybrid battery thermal management system, aiming to enhance the thermal performance of the hybrid system. An experimental platform comprising a liquid-cooled hybrid phase change material (PCM) cooling system with five 25 Ah lithium iron phosphate batteries was established and validated, the response surface method is employed to elucidate the functional relationships between pulsed flow parameters and thermal responses, while analysis of variance evaluates parameter significance. On this basis, a multi-objective optimization problem aimed at simultaneously minimizing the maximum temperature and the maximum temperature difference is formulated and solved using the NSGA-II algorithm, yielding a Pareto-optimal solution set. The results indicate that, except for the coolant inlet temperature, the pulse duty cycle is the most influential factor affecting both the maximum temperature and the maximum temperature difference. Increasing the duty cycle reduces the maximum temperature but increases the maximum temperature difference. Furthermore, the TOPSIS and LINMAP decision-making methods are applied to determine the optimal combination of pulsed flow parameters. Experimental validation demonstrates that the maximum deviation between the predicted and measured values is within 4.32%. Compared with the continuous flow case, the TOPSIS solution achieves a 22.89% reduction in temperature difference, accompanied by a marginal decrease of 0.30% in maximum temperature, the LINMAP solution reduces the maximum temperature by 3.44%, while maintaining the temperature difference within an acceptable and safe range.