Abstract:

To enhance the safety of lithium-ion batteries duning road transportation, non-contact sensing technologies were used to investigate thermal runaway behavior and early warning methods during transport. A transport container experimental environment and a thermal runaway monitoring system were established. The thermal runaway trigger tests were conducted using lithium nickel cobalt aluminum oxide (NCA), lithium nickel cobalt manganese oxide (NCM), and lithium iron phosphate (LFP) battery packs at 50% state of charge (SOC). The thermal runaway and combustion characteristics of the three types of batteries were compared within the transport container. The safety status of lithium-ion batteries during transport was effectively monitored by integrating electrochemical gas sensors (H₂ and CO) with infrared temperature sensors, and the early warning effectiveness of various non-contact sensors was evaluated. The results indicate that NCA exhibits the fastest thermal propagation, followed by NCM and LFP. Furthermore, NCA, NCM, and LFP display distinct warning patterns, in which temperature signals preceded gas signals, temperature signals slightly preceded gas signals, and gas signals preceded temperature signals, respectively. For battery packs of NCA, NCM and LFP, with 100 ℃ or 0.001% as the warning threshold, warnings can be issued 4, 125 and 2 115 seconds before thermal runaway, respectively.

Key words: road transportation, lithium-ion batteries, thermal runaway, monitoring and warning, characteristic gases, infrared temperature sensing