Preparation and Performance of Isolated Liquid-Cooled Cables with High Thermal Conductivity Tubes

To solve thermal resistance bottleneck of isolated liquid-cooled cables for high-voltage fast charging systems of new energy vehicles and improve heat dissipation performance under high current-carrying conditions, two types of isolated liquid-cooled cable structures (indirect cooling type and copper-clad water type) were designed. High thermal conductivity modified cross-linked polyethylene (XLPE) tubes were used to replace conventional fluorinated ethylene propylene (FEP) tubes as cooling channels. 30-minute current-carrying temperature rise comparison tests were conducted by means of a temperature rise testing machine. 400 A and 700 A DC currents were applied to the two types of cables respectively, and temperature rise characteristics under different tube material matches were monitored and analyzed. It was shown by the results that after the indirect cooling type cable was matched with high thermal conductivity modified XLPE tube, the 30-minute temperature rise was reduced by 20.9 ℃ compared with the FEP tube sample; after the copper-clad water type cable was matched with high thermal conductivity modified XLPE tube, the 30-minute temperature rise was reduced by 28.1 ℃ compared with the FEP tube sample. Significant heat dissipation enhancement effect was exhibited by high thermal conductivity modified XLPE tube in both types of cable structures, and heat accumulation under high current-carrying conditions could be effectively alleviated. Thermal management capability of isolated liquid-cooled cables could be optimized by the formed cable structure design and high thermal conductivity tube selection scheme, reliable technical support could be provided for performance upgrading and lightweight design of cables for high-power fast charging systems, and a positive role could be played in promoting engineering application of high-voltage fast charging technology for new energy vehicles.