Study on Multi-Parameter Evolution Characteristics of 314 Ah High-Capacity LiFePO4 Batteries During Thermal Runaway Under Various Abuse Conditions

High-capacity energy storage batteries contain complex physicochemical systems. The thermal runaway within batteries pose significant challenges to widespread application in energy storage systems. To better investigate the safety warning thresholds of battery energy storage systems, it is necessary to study the thermal runaway characteristics and behavioral patterns of batteries under various abusive conditions. This study focuses primarily on energy storage batteries in actual operation and on simulating real-world operating conditions. A multi-parameter experimental monitoring platform based on temperature, voltage, expansion force, and particulate matter concentration was established to investigate the multi-parameter variation patterns and distinctive characteristics of thermal runaway in energy storage cells under electrothermal coupling and overcharging abuse conditions. The results show that under electrothermal coupling conditions, the initial critical moment of thermal runaway occurs 530 s earlier than under overcharging conditions, with a maximum temperature reaching 457.2 °C; however, under overcharging conditions, the thermal runaway process is more severe, with a maximum temperature reaching 580.9 °C. A comparative analysis of the early warning thresholds for multiple parameters revealed that the threshold based on mechanical signals appears the earliest. Under electrothermal coupling conditions, the force signal preceded the injection valve signal, voltage signal, and temperature signal by 121 s, 305 s, and 732 s, respectively, with a maximum expansion force of 6836 N; under electrical abuse conditions, the force signal preceded the aforementioned signals by 458 s, 711 s, and 1733 s, respectively, with a maximum expansion force reaching 7566 N. This study provides a basis for the thermal management design and safety control of energy storage batteries. This study offers insights for safeguarding the proper operation of battery energy storage systems.