Structure design and effect analysis on refrigerant cooling enhancement of battery thermal management system for electric vehicles

A liquid-cooled battery thermal management system, consisting of a refrigerant flow through a cold plate, allows the battery to recharge cycles at aggressive rates and temperatures. Based on the validated fluid-solid coupling model, the design and evaluation of the refrigerant-based thermal management structure, and the analysis and control of characteristic parameters under different conditions are explored in this paper. A thermal management structure, involving the tube side and cross-section of the cold plate, reaches a compromise between heat exchange quantity, required power consumption, mass, volume. For the controllable parameters, results show that the refrigerant mass flux has an optimal solution for thermal management, yet the evaporation temperature is the limit of system stability and control. Based on the refrigerant properties, a cascade-change strategy with priority is proposed to consider both temperature drop and temperature uniformity of the battery. Besides, although the refrigerant-based thermal management structure cannot prevent the thermal abused of a single cell, it can suppress the thermal runaway propagation from one to adjacent cells.