Simulation study of lithium-ion battery thermal management system based on a variable flow velocity method with liquid metal

A battery thermal management system (BTMS) is commonly used to control the battery temperature within the optimal temperature range. This paper presents a novel BTMS based on a liquid cooling method with liquid metal, which uses liquid metal as a coolant to achieve better cooling capacity and energy efficiency. An electrochemical-thermal coupled model is proposed to investigate the thermal behavior during discharge. A variable flow velocity strategy (VFVS) that can select the optimal flow velocity according to the discharge stage and specific operating conditions is used in the proposed BTMS. Numerical simulation results show that liquid metal can provide better cooling capacity than water and can be used in some extreme conditions. Within a certain range of the volume flow rate, a structure with a smaller number of copper pipes but higher flow velocity has better cooling performance. In addition, compared with a traditional BTMS, which uses a constant flow velocity strategy (CFVS), the proposed BTMS reduced the power consumption of the pump by 47%, 25.6% and 47% under constant ambient temperature with variable C-rate (CTVC), constant C-rate with variable ambient temperature (CCVT) and variable ambient temperature with variable C-rate (VCVT) operating conditions, which eventually reduced the energy consumption.