A recent study published in Engineering presents a novel approach to address the challenges of high-power direct current fast charging (DC-HPC) in electric vehicles (EVs). The research, led by a team from China Agricultural University, focuses on developing a synergetic cooling and charging strategy using a gallium-based liquid metal flexible charging connector (LMFCC).
As the demand for EVs grows, DC-HPC technology, especially for megawatt-level charging currents (≥1000 A), is crucial for reducing charging time. However, it brings the problem of instantaneous thermal shocks. Conventional cooling methods that separate current transmission and heat transfer struggle to achieve both flexibility and high-efficiency cooling.
The LMFCC proposed in this study has several advantages. It can efficiently dissipate ultra-high heat flux while carrying superhigh current. Thanks to the excellent liquidity and conductivity of liquid metal, the LMFCC shows exceptional flexible operability with a bending radius of 2 cm and high transmission stability even under significant deformation, outperforming solid metal connectors.
The researchers optimized a compact induction electromagnet-driven method. By adjusting the current and magnetic flux distribution, they enhanced the liquid metal (LM) flow rate and active cooling capacity of the LMFCC system. This method also helps suppress end effects. A three-dimensional multi-physics numerical model and a synergetic cooling and transmission test platform were established to comprehensively evaluate the performance of the LMFCC under different conditions.
The experimental results are promising. The LMFCC demonstrated good electrical stability under torsional and bending conditions. Regarding cooling performance, at a charging current of 1000 A, the temperature difference between the maximum temperature and the external environment remained at 54.3 °C, showing its excellent heat extraction and dissipation capabilities. The system's cooling performance can be further improved by adjusting parameters such as the length, diameter of the charging cable, and the flow rate of the liquid metal.
This new synergetic cooling and charging strategy represents a significant step forward in ultra-high heat flux thermal management. It has the potential to enable the development of simple, reliable, and lightweight charging systems with high charging power. Although it is still in the research stage, it offers new possibilities for the future of the electric vehicle industry, potentially accelerating the widespread adoption of electric vehicles.
The paper "Liquid Metal-Enabled Synergetic Cooling and Charging of Superhigh Current," authored by Chuanke Liu, Maolin Li, Daiwei Hu, Yi Zheng, Lingxiao Cao, Zhizhu He. Full text of the open access paper: https://doi.org/10.1016/j.eng.2024.11.035
