Discovering Early‐Stage Gas Generation Kinetics Enables Thermal Runaway Early Warning in Lithium‐Ion Batteries

ABSTRACT Early warning of thermal runaway (TR) in lithium‐ion batteries remains constrained, as conventional indicators emerge after irreversible failure. Here, we establish a novel framework to advance gas‐based early warning by uncovering the earliest chemically driven processes preceding heat accumulation (HA). Operando gas measurements reveal a previously unrecognized chemical activation (CA) stage prior to HA, where coupled electrolyte–electrode reactions initiate at 60, causing continuous trace gas accumulation without measurable temperature rise. To elucidate the underlying mechanisms, a physics‐informed gas generation kinetics network (GGKNet) is developed by coupling chemical reaction kinetics with gas adsorption‐desorption, electrolyte evaporation, and lithium–involved reactions. The framework quantitatively captures species‐resolved gas generation across states of charge and reconstructs pathway‐resolved kinetics during CA and HA stages. Validations under TR scenarios demonstrate that GGKNet achieves superior prediction of gas onset timing, temporal evolution, and spatial distribution, thereby translating kinetic‐level insights into guidance for practical early warning systems.