Comparing the thermal runaway characteristics in sodium-ion batteries and Li-ion batteries with layered oxide cathode materials: Influence of state of charge level

The present investigation compares the thermal runaway behaviour of sodium-ion batteries (SIBs) and lithium-ion batteries (LIBs) with layered oxide cathodes. The experiment involved subjecting 30 single 18650-type cells (15 SIBs with NFM cathode and 15 LIBs with NMC cathode) to thermal abuse at five different state of charge (SOC) levels inside a 10-L reaction vessel. The temperature and pressure data were collected to characterize the thermal runaway behaviour including the gas production and associated hazards. A Fourier-transformed infrared (FTIR) spectrometry was performed to analyse the composition of the released gases. The results revealed that venting occurred in both cell types within a pressure range of 1.04 bar–1.18 bar. The SIBs exhibited maximum pressures ranging from 1.2 ± 0.02 bar to 4 ± 0.3 bar during thermal runaway, while the LIBs reached maximum pressures between 1.42 ± 0.02 bar to 5.8 ± 0.40 bar with a dependence on SOC level. The study demonstrated that the energy release characteristics of SIBs is comparable to those of LIBs. Among the gas components analysed, carbon monoxide (CO) posed the most safety concern due to its toxicity hazard and explosibility. • Thermal runaway in sodium-ion and lithium-ion cells is characterized. • Influence of SOC level on battery thermal decomposition behaviours is studied. • The characteristic energy releases are compared. • The explosion hazard and gas emission at thermal runaway were investigated.