Glass fiber-reinforced intumescent flame-retardant systems in extreme fire conditions—part 2: Burn-through testing and modeling.

The article evaluates the fire barrier performance of STAMAX™ 30YH570, a glass fiber-reinforced intumescent flame retardant polypropylene (FRPP), under burn-through conditions simulating electric vehicle (EV) battery thermal runaway scenarios. Using a burn-through test analogous to the UL2596 standard (focused on battery pack casings), the material demonstrated the ability to withstand 30 minutes of exposure without burn-through. A three-dimensional pyrolysis model incorporating heat and mass transfer, decomposition kinetics, and thermal expansion via moving boundary conditions was developed and validated against experimental backside temperature data, showing good predictive accuracy. Parametric studies revealed that the thermal barrier effectiveness primarily depends on condensed-phase thermophysical properties and environmental factors such as convective heat transfer and flame heat flux, while gas diffusion coefficients had minimal impact. The model offers a valuable tool for predicting fire resistance of intumescent FR polymer composites in EV battery protection and can be adapted for various fire scenarios.