Numerical investigation of suppressing thermal runaway propagation in a lithium-ion battery pack using thermal insulators

Thermal runaway propagation (TRP) in a lithium-ion battery pack is crucial to its safety concerning the potential hazards of fire or explosion. In current study, a TRP suppression method for a 4 × 4 battery pack using three insulation materials, silicate, ceramic and glass fiber boards, is numerically investigated. Reliability of the model is first verified by experimental temperature of a single battery during TR. Then, three sets of TRP scenarios initiated by external heating are studied to reveal the effects of insulation type, thickness (0.5–4 mm) and layout. The results show that thermal conductivity of insulation impacts its performance more greatly than thickness, and glass fiber outperforms silicate and ceramic fibers in preventing TRP. Bidirectional layout (BL) of insulation boards performs better than unidirectional layout (UL). For UL, row-to-row TRP exists and the TRP process is accelerated compared with non-insulation case if insulation boards fail, implying UL can prevent TRP only if the row-to-row TRP is inhibited. While for BL, TRP is only observed for 0.5 mm silicate fiber boards, and the critical heating power (6.5 kWm⁻²) triggering TRP in battery pack is much lower. The outcomes may provide useful theoretical bases and suggestions for safety design and risk assessment of battery pack.