Experimental and modeling investigation on the gas generation dynamics of lithium-ion batteries during thermal runaway

The gas generation and rupture are the special features of the thermal runaway (TR) of lithium-ion batteries (LIBs). The LIB's gas generation dynamics during TR are investigated using the extended-volume accelerating rate calorimeter and a gas-tight canister. The pressure within canister is measured, and the internal gas could be regarded as a lumped system before TR thanks to the adiabatic condition. The pressure increase is about 100 kPa at the safety valve opening, and the corresponding gas release is approximately 10 mmol. For 100% SOC cells, the peak pressure recorded before the canister pressure relief is 2.566 MPa. The gas generation rate is approx-imately proportional to the temperature increase rate, which facilitates the simulation on the gas generation because temperature is easier to measure. The gas generation process can be divided into different stages, and the multi-stage kinetics parameters (Frequency factor and activation energy) of the gas generation process are calculated, which predict the evolution of internal pressure and rupture behavior of LIB under external heating condition.