Mitigating thermal runaway propagation of NCM 811 prismatic batteries via hollow glass microspheres plates

The propagation of thermal runaway in Lithium-ion battery modules can escalate fire hazards and damage in energy storage systems. More effective strategies are needed to ensure the safe application of high-energy lithium-ion batteries and alleviate the thermal runaway propagation. This work explores the use of ultra-light plates based on hollow glass microspheres (HGM) as firewalls in the large-format battery module. A systematic experimental study is conducted using the prismatic battery with LiNi0.8Co0.1Mn0.1O2 (NCM 811) cathode and HGM firewalls with different thicknesses. Performance tests suggest that the composite plate with 60 wt% HGM, 25 wt% curing agent, and 15 wt% flame retardant is most effective in mitigating thermal runaway propagation. Without firewalls, the thermal runaway propagation rate increases from 0.43 cell/min to 0.85 cell/min as the SOC level increases from 25% to 100%. Inserting HGM plates can effectively slow down thermal runaway propagation, where the 3-mm HGM plates can successfully block the thermal runaway. A simplified heat transfer model is also proposed to explain the performance of the firewall in inhibiting thermal runaway and help to optimize the safety design for battery modules. This work provides important insights into the thermal runaway risks and safety measures of large battery systems.