Simulation-Based Investigation on Thermal Propagation in Li-ion Battery Modules with Regard to the Thermal Management System

Thermal propagation in Li-ion battery systems is affected by a wide range of influencing factors including chemical cell properties as well as thermal transport phenomena. Due to the dependence on thermal surroundings it is crucial to regard the entire battery system including peripheral components when assessing thermal runaway and propagation risks. This study proposes a simulation-based approach to support design and dimensioning of potential safety measures. It is based on a chemical model for the thermal runaway decomposition reactions combined with 3D thermal simulations. This is applied on exemplary ten cell battery pack in order to investigate on effects on heat transfer during thermal propagation. Insulation and cooling systems are included in the simulation environment for that purpose. It is found that propagation behavior significantly depends on their positioning within in pack and on thermal boundary conditions. Placing too many barriers may exacerbate hazardous situations instead of mitigating them due to heat accumulation effects. Cooling systems are shown to be able to support thermal runaway mitigation strategies but their effectiveness is limited by thermal transport inside the battery cells.