Jet behavior of prismatic lithium-ion batteries during thermal runaway

Insights into jet behavior are significant for the safe application of lithium-ion batteries and the design of thermal protection systems. In this study, a fully charged 38Ah Li(Ni1/3Co1/3Mn1/3)O-2/graphite prismatic lithium-ion battery was heated on one side to trigger thermal runaway. An unignited jet behavior was characterized by jet manifestation, temperature, and velocity. Results showed that the jet process could be divided into four stages, and special phenomena such as jet tilt, spark burst, and jet ignition might occur at the third stage. The similarity between the maximum temperature of the jet in this work and the jet fire in a previous study indicated that the thermal hazard of the jet could not be underestimated. The average jet velocity of 8.3 m.s(-1) at the third stage was obtained with a high-speed imaging technology. A prediction method of the jet velocity was developed on the basis of the internal pressure of the battery. This work could enhance our understanding of the unignited jet behavior and provide references for the safety design and hazard prevention in battery storage systems.