Thermal runaway gas warning is an important safety defense line for energy storage systems

and the diffusion and distribution of gases are crucial to the effectiveness of thermal runaway warning. To study the escape and spatiotemporal distribution characteristics of gases in the early stage of thermal runaway

this paper simulates the escape law of H2 when a single battery in a prefabricated cabin energy storage system experiences thermal runaway at different positions

and analyzes the spatiotemporal distribution characteristics of gas in the cabin based on experimental results. The research results show that

after the thermal runaway position changes from A (middle of the bottom layer of the battery cluster) to B (corner of the bottom layer of the battery cluster)

the difference in response time of H2 sensors in the entire space of the cabin in simulation and experiment increases by 15 s and 25 s

respectively. The average maximum H2 volume fraction and the average maximum characteristic value of sensors in the upper and middle sections of the cabin decrease

the steady-state H2 volume fraction and steady-state characteristic value of sensors in most areas of the cabin decrease

and the difference in steady-state volume fraction and steady-state characteristic value increase. The gas generated by the bottom battery is blocked by the module above it

which can cause spatial asymmetry of gas transient escape behavior and steady-state distribution. In prefabricated cabin energy storage systems

the upper gas sensors inside the cabin should not be arranged in corners

and the middle and lower gas sensors should not be arranged at both ends of the aisle. When thermal runaway occurs in the bottom corner of the battery cluster

the gas detection conditions are more severe

and the overall response effect of the cabin sensors is relatively poor compared to the situation of thermal runaway in the middle of the battery cluster bottom. The research results can provide reference for the design and optimization of gas sensors layout schemes in energy storage systems.