关键词: 电动汽车；高压继电器；触点粘连；失效机理

Abstract: High-voltage relays, as core safety components of the power system in new energy vehicles, play a critical role in controlling and protecting the power circuits of electric vehicles. The issue of contact adhesion failure in these relays poses a significant threat to the safety and reliability of the entire vehicle. To systematically address this issue, this study, based on actual fault cases from a specific vehicle model, combines scanning electron microscopy (SEM) analysis of contact material migration and molten layer formation mechanisms to reveal the physicochemical mechanisms behind high-voltage relay adhesion failures. The research establishes morphological characteristic-operational condition mapping rules and proposes a "failure mechanism－diagnostic strategy－preventive technology" three-dimensional research framework. It also conducts systematic optimization to address potential causes of adhesion. Through measures such as battery management syste software and hardware control, relay component optimization, and harness inspection, the market relay failure rate has been significantly reduced from 57.4 to 10.9, demonstrating the effectiveness of these optimization measures. This study provides important theoretical support and practical guidance for improving the reliability and safety of high-voltage relays in electric vehicles.

Key words: electric vehicle; high-voltage relay; contact welding adhesion; failure mechanism