Delayed liquid cooling strategy with phase change material to achieve high temperature uniformity of Li-ion battery under high-rate discharge

This work aims at achieving high temperature uniformity of large battery, modules during high C-rate discharge with a low flowrate fluid. A new scheme of delayed liquid cooling combing phase change material (PCM) and liquid cooling is proposed for a Li-ion battery pack with 40 cylindrical cells. A heatsink is designed and optimized with a numerical model, then a real cooling plate is manufactured and its performance is verified with experiment. The results show the low cooling temperature of liquid could increase the temperature difference of the battery pack and reduce the discharge capacity. Therefore, a high inlet water temperature should be the priority if the battery temperature is within the limit. Compared with traditionally continued cooling, delayed cooling system shows better performance especially under high discharge current up to 4C with a cooling flowrate of 40 L/h. Delayed cooling significantly reduces the temperature difference between batteries and within a battery. Furthermore, this new cooling mode shortens the period of liquid cooling thereby saving the power consumption of the system. This hybrid cooling system can be useful in the design of battery thermal management for the battery used under high-rate discharge during climbing hills or other high-power cases.