Quantification of Lithium Battery Fires in Internal Short Circuit

Single-layer internal shorting in a multilayer battery is widely considered among the "worst-case" failure scenarios leading to thermal runaway and fires. We report a highly reproducible method to quantify the onset of fire/smoke during internal short circuiting (ISC) of lithium-ion batteries (LiBs) and anode-free batteries. We unveil that lithium metal batteries (LMBs) with or without liquid electrolytes are more dangerous than LiBs upon internal shorting, igniting fires within a time scale of 1–3 s followed by similar or larger combustion heat release. This implies that all solid state batteries (ASSBs) with lithium anodes will have safety concerns, and much research is needed to scrutinize ASSB safety. Also, there exists a threshold in the shorting current to trigger a fire in LMBs, and its precise control is key to reproducing ISC behaviors. Finally, we unravel the profound role of oxygen in fire/smoke formation and present new suggestions for developing safe ASSBs.