关键词: 钠离子电池模组, 热失控行为, 电滥用

Abstract:

This study aims to address the escalating safety challenges of sodium-ion batteries in large-scale energy storage systems. By conducting a 0.5C overcharge abuse test on a module composed of thirteen 185Ah prismatic cells connected in series, the multiphysics failure process of its thermal runaway was systematically analyzed. The experimental results reveal a chain-reaction failure mechanism driven by the coupling of electrical, chemical, thermal, and mechanical fields. The earliest precursor signal was identified as a slow, linear increase in internal expansion force, which was attributed to gas generation from localized side reactions induced by overcharging. This signal appeared significantly earlier than any notable electrical or thermal anomalies. As the overcharge continued, the voltage curves of individual cells began to diverge, indicating an escalation in internal inconsistency and cumulative damage within the module. Ultimately, a single "weak link" cell experienced an internal short circuit upon reaching a critical damage threshold, manifested by an instantaneous voltage collapse and an exponential temperature surge, thereby triggering thermal runaway. The catastrophic failure of this single point released immense heat, which subsequently initiated a domino-like thermal propagation to adjacent cells, leading to the destruction of the entire module within a short period. In summary, this research substantiates the "local trigger, global destruction" failure mode for sodium-ion battery modules. Furthermore, it highlights the critical value of internal pressure monitoring as the earliest warning indicator, providing a significant theoretical basis and empirical data to support the design of safer Battery Management Systems and energy storage systems in the future.

Key words: Sodium-ion battery module, thermal runaway, electrical abuse