Investigation into the Corrosion Mechanism of High-Voltage Cables in Eco-Friendly Vehicles

Abstract

This study investigates corrosion mechanisms in high-voltage (HV) cable connectors used in eco-friendly vehicles, focusing on galvanic and stray current corrosion under realistic operating conditions. Severe oxi- dation and pitting were observed at the interface between aluminum connectors and copper ground ter- minals, which are coated with tin (Sn). Mechanical fretting and electrical stress accelerated Sn layer breakdown, exposing the aluminum substrate and forming a galvanic couple with copper. A series of com- bined corrosion tests were carried out under vibration, DC bias, moisture ingress, and their simultaneous action. SEM/EDS analyses confirmed significant fretting wear and Al₂O₃ formation, especially when mechanical and electrical loads acted together. Leakage current measurements showed that both AC and DC systems produced current densities within critical stray current corrosion thresholds, particularly during deceleration and braking. These results reveal a synergistic degradation mechanism involving vibra- tion, electrolyte exposure, and electrical bias. To mitigate corrosion, structural enhancements such as vibra- tion-resistant fastening and environmental sealing are proposed. Overall, the findings provide new insight into HV connector failure mechanisms and present practical design recommendations to enhance durabil- ity and reliability in electric mobility applications.