Cooling and preheating performance of dual-active lithium-ion battery thermal management system under harsh conditions

Abstract

A dual-active battery thermal management system (DA-BTMS) combining liquid cooling with thermoelectric cooling is proposed to improve thermal management. Through numerical simulation and physical experiments, the optimal configuration of the system is determined by comparing three different thermoelectric cooler (TEC) arrangements, and the effects of the TEC’s input current and coolant mass flow rate on the batteries’ heat dissipation are investigated. In addition, the TEC’s cold and hot ends can be interchanged to preheat the battery in a cold environment by reversing the input current. The optimal step-preheating strategy is put forward aiming at the preheating of batteries. The results show that, the DA-BTMS with pure liquid cooling can easily control the temperature within an ideal temperature range with the optimal coolant mass flow rate of 0.59 g/s at a discharge rate of 2C and ambient temperature of 40 °C. While the discharge rate is 3C, DA-BTMS can still reliably keep the system under the action of TEC auxiliary cooling. At an over-high ambient temperature of 50 °C, the system maximum temperature sharply decreases from 50 °C to 42.32 °C at a discharge rate of 2C with the optimal input current of TEC 1.6 A owning to the refrigeration action of TEC. The Step-preheating method is put forward and the optimal strategy is determined, which can ensure the preheating rate of 0.77 °C/min for the battery pack. The proposed system not only improves the space utilization of the battery pack but also maintains the maximum temperature of the battery module in a suitable range under harsh cold and hot ambient conditions. Compared with the conventional pure TEC cooling method, it can effectively save energy consumption.