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

摘要： 高压继电器作为新能源汽车动力系统的核心安全部件，承担着电动汽车动力电路控制 与保护的关键任务，其触点粘连失效问题严重威胁整车安全性与可靠性。为系统化解决该问 题，文章以某车型实际故障案例为基础，结合扫描电子显微镜（SEM）分析触点材料迁移与 熔融层形成机制，揭示了高压继电器粘连失效的物理化学机理。建立了触点形貌特征与工况 映射规则，提出了“失效机理－排查策略－预防技术”三维研究框架，并针对可能导致粘连 的原因进行了系统优化。通过电池管理系统软硬件控制、继电器本体优化及线束检查等措施， 市场继电器失效率显著降低，从 57.4 降至 10.9，验证了优化措施的有效性。该研究为提升电 动汽车高压继电器的可靠性和安全性提供了重要的理论支持和实践指导。

关键词: 电动汽车；高压继电器；触点粘连；失效机理