Self-driven liquid metal cooling connector for direct current high power charging to electric vehicle

Abstract

Direct current-based high power charging (DC-HPC) technology is expected to shorten the charging time of electric vehicles (EV) significantly and lessen the range anxiety. However, a high charging current would cause a remarkable temperature rise of the charging connector due to the Joule heat, which must be adequately removed to keep its durability and safety. This paper reported a novel concept of the self-driven liquid metal (LM) cooling connector (LMCC) used for DC-HPC. The room-temperature LM of Galinstan filled in the flexible tube is applied as the current-carrying conductor and circulated-cooling fluid simultaneously. The circulation-flow LM is driven by the designed electromagnetic force through coupling the charging current and magnetic field from a pair of permanent magnets, which does not need additional pumping devices. A principle experiment is conducted to demonstrate the driving and cooling performances of LMCC, which shows excellent circulation flow rate (with the flow rate of 0.75 L/min and the driven pressure head of 44.7 kPa) of the LM in the flexible tube (diameter of 6 mm and length of 2.65 m) and only achieves a temperature rise of about 13 °[email protected] Both 3D multi-physics simulation and theoretical models are also established and demonstrated by experiment results to accurately evaluate the impacts of the charging current, magnetic field, and flexible tube size on the performance of self-driven LMCC. The results indicate that increasing the diameter of the flexible tube could significantly reduce its temperature rise induced by a high charging current and does not affect its flexibility. A super-low temperature rise of 10.6 °[email protected] for the charging cable (the diameter of 10 mm and length of 3 m) is designed. This work provides a new strategy for the heat dissipation technology of DC-HPC charging connectors.