Investigation of the Impact of Radiative Shielding by Internal Partitions Walls on Propagation of Thermal Runaway in a Matrix of Cylindrical Li-Ion Cells

Abstract

Understanding the nature of onset and propagation of thermal runaway in a Li-ion battery pack is critical for ensuring safety and reliability. This paper presents thermal runaway simulations to understand the impact of radiative heat transfer on thermal runaway onset and propagation in a pack of cylindrical Li-ion cells during transportation/storage. It is shown that radiative properties of the internal partition walls between cells commonly found in battery packs for transportation/storage play a key role in determining whether thermal runaway propagation occurs or not. Surface emissivity of the internal partitions is shown to drive a key balance between radiative heat absorbed from the trigger cell and emitted to neighboring cells. It is shown that a high thermal conductivity partition may greatly help dissipate the radiatively absorbed heat, and therefore prevent onset and propagation. Therefore, choosing an appropriate emissivity of the internal partitions may offer an effective thermal management mechanism to minimize thermal runaway. Emissivity of the cells is also shown to play a key role in radiative heat transfer within the battery pack. This work contributes towards the fundamental understanding of heat transfer during thermal runaway in a battery pack, and offers practical design guidelines for improved safety and reliability.