Fire behavior and hazard propagation in a lithium-ion battery energy storage cabin under microgravity environments

As the demand for energy storage in long-duration space missions grows, lithium-ion batteries, valued for high energy density and cycle life, are increasingly deployed in spacecraft and lunar habitats. However, their thermal runaway fire behavior in microgravity remains poorly understood. This study employs validated simulations to investigate fire evolution in an energy storage cabin under gravity levels from 1G to 0.001G, specifically selecting the central ignition position as the worst-case scenario for microgravity. Results show the peak heat release rate drops from 9098 kW at 1G to 401 kW at 0.001G, representing a reduction of 95.6%., while fire duration extends over 9-fold. A nonlinear transition near 0.01G marks the onset of diffusion-dominated combustion. Driven by the suppression of buoyancy, heat is trapped around the source, resulting in a weakened vertical temperature gradient but significantly enhanced local thermal stresses. Toxic gas analysis reveals that due to weak diffusive transport, CO retention times increase by over 200%, with localized concentrations up to 1.5 times higher than at 1G. This work reveals the unique multiphase cascading failure and heat accumulation mechanisms in microgravity, providing critical data for spacecraft fire safety and extraterrestrial energy storage protection.