A novel pulse resistance based thermal runaway early detection approach for lithium-ion and sodium-ion batteries

Temperature monitoring of lithium-ion batteries (LIBs) and sodium-ion batteries (SIBs) is essential for safe operation, as excessive temperature can trigger a thermal runaway (TR) event. Although surface temperature sensors have traditionally been used, their limitations have led to the exploration of alternative methods. Notably, estimating temperature based on pulse resistance ( R DC ) has emerged as a promising approach. Nonetheless, this method has not yet been investigated at temperatures exceeding the cell’s safety limits, highlighting a research gap for its application in TR early detection. In this study, the R DC -temperature relationship was characterized at temperatures exceeding the cell’s safety limits for two different LIB technologies and a SIB. The results revealed a turning point in the R DC -temperature relationship between 60 °C and 70 °C for both LIB technologies and at approximately 110 °C for the SIB. From this turning point, R DC increases with increasing temperature. This contradicts the loss of sensitivity of R DC to temperature variations predicted by the Arrhenius model at temperatures typically encountered during a TR event. Finally, a novel TR early detection approach based on the characterized R DC behavior during a TR event is proposed. The strength of the method lies in the combination of two monitored R DC properties changing during TR. • Thermal runaway can be detected early by monitoring the pulse resistance. • Combining two pulse resistance characteristics enhances detection reliability. • There is a turning point in the pulse resistance-temperature relationship. • The Arrhenius model cannot describe the resistance’s behavior at high temperature. • Current collectors’ resistance significantly contribute to the turning point.