Abstract: To explore the thermal runaway behavior and combustion characteristics of sodium-ion battery, the thermal runaway characteristics of sodium-ion battery under different trigger conditions were studied based on the heat release rate test system, and the combustion characteristics (heat release rate, total heat release, smoke production rate, total smoke production) were compared with lithium-iron phosphate battery and lithium ternary battery. The results show that under 0.5C overcharge conditions, the surface temperature of sodium-ion battery can reach up to 834.9 °C, with a maximum heat release rate of 156.99 kW and a maximum smoke production rate of 1.65 m2/s. Under the heating condition of 7 ℃/min temperature rise rate, the maximum surface temperature of sodium-ion battery can reach 594.7 ℃, the maximum heat release rate is 227.41 kW, and the maximum smoke production rate is 1.54 m2/s. The combustion performance of sodium-ion battery was compared with that of lithium-ion battery. The results show that the combustion characteristics of sodium-ion battery are between those of ternary lithium battery and lithium-iron phosphate battery. Ternary lithium battery has the highest heat release rate and smoke production rate, while lithium-iron phosphate battery has the highest total heat release.

Key words: sodium-ion battery; thermal runaway; combustion characteristics; thermal release characteristics; smoke generation characteristics