不同荷电状态磷酸铁锂电池热失控温度与产气特性分析

To better prevent and control explosion accidents in energy storage stations, it is necessary to conduct research on the thermal runaway process of energy storage batteries and to conduct an in-depth analysis of the produced gases and their components for potential safety hazards. This study conducted in-depth research on the thermal runaway process of energy storage batteries. Through 500 W heating tests on 60 Ah lithium iron phosphate batteries at different State of Charge (SOC), the study systematically analyzed the potential hazards of the produced gas components. FLACS software was used to study the hazardous nature of the gas components and, combined with the temperature-voltage-gas production curve evolution, summarized the thermal runaway process and gas production process of the battery. The research divided the thermal runaway process of the battery into three stages: thermal accumulation stage (Stage I), thermal equilibrium stage (Stage II), and thermal runaway and cooling stage (Stage III). Besides, a thorough analysis of the gases produced by the battery was conducted, dividing the gas production process into four stages. It was found in the study that the thermal runaway of the battery triggers gas production, and the amount of gas production increases with the development of thermal runaway. Furthermore, FLACS software is used for explosion simulation, simulating the explosion behavior of premixed gases, and calculating the explosion limits of the gas components. The simulation and calculation results indicate that the variation in battery SOC has an impact on the combustion behavior of the combustible gases; the explosion limits and explosion overpressure of the mixed combustible gases increase with increasing in SOC. These research findings have important theoretical guidance significance for the safety protection of energy storage batteries and can provide a basis for the safety design of batteries, the formulation of emergency plans, and accident response.