Muhammad Mehdi Abbas, Byoungchul Kwon, Vinay Premnath, Judith Jeevarajan, Ankur Jain
Fire hazards due to thermal runaway pose a serious threat to the safe functioning and storage of lithium-ion battery packs. Unique challenges related to prevention of thermal runaway propagation, fire suppression and extinguishment arise in the case of large-scale battery storage systems. This work presents a multiphysics computational framework for modeling fires caused by thermal runaway and fire suppression in very large lithium-ion battery storage systems. A previously reported single-cell heat release rate profile is adapted to estimate pack-level heat release rate by using a staggered batch-based thermal runaway propagation approach drawn from a normal distribution. This approach avoids the complex and computationally intensive task of modeling Arrhenius reactions explicitly. The accuracy of this approach is validated by comparison against experimental measurements on a 3 kWh battery module. The simulation model is used to study the effects of various parameters on fire intensity in the immediate surroundings of the module, including heat release rate, speed of thermal runaway propagation and the release of combustible gases from the cell. Increased heat release rate is found to lead to higher temperatures, while faster propagation produces sharp temperature spikes, as expected. Smaller cell vent sizes are found to result in higher temperatures due to insufficient ventilation of hot gases. Finally, the benefit of prompt sprinkler activation in reducing peak temperatures is also investigated. Simulations are also carried out to highlight and quantitatively understand the role of the timing of sprinkler activation and fire suppressant flow rate. In addition to developing a useful modeling tool for thermal runaway and fire extinguishment, this work also identifies important techniques to control and minimize the risk of catastrophic failure associated with thermal runaway of large-scale lithium-ion battery storage.