The experimental research for a thermal failure LiFePO4 battery: Venting behavior, multi-information monitoring and early warning strategy

Lithium-ion battery (LIB) thermal runaway (TR) and gas venting characteristics have great significance for battery safety design and early warning strategy. In this article, the experimental research for 280 Ah LiFePO4 batteries TR and gas venting behavior has been carried out by the multi-parameters monitoring method. The TR temperature, velocity, H2 concentration, CO concentration, etc. can be detected by this method. The results show that battery TR exhibits five distinct phases. Among them, the second and fourth phases can be identified as the key parts of which the highest temperatures can reach to 150 °C and 200 °C, respectively. The maximum gas venting velocity is 20 m/s and 16.7 m/s. What's more, The concentration variation rate of H2 and CO can be detected with maximum values of 2442 ppm/s and 411.5 ppm/s. From an early warning perspective, the angle between different vectorial parameters can be an innovative strategy for battery thermal failure detection. Consequently, this article compared different vectorial angles as warning signs and assessed the time advance behavior. The results show, compared to the battery safety valve cracked time, when the angle between the parameter of H2 and CO concentrations is a warning sign, the warning time can be advanced by 64 %. In conclusion, this research can provide an important reference for battery thermal safety design, failure hazard detection, and TR early warning, not only for battery energy storage systems (ESS) but also for electrified transportation. This method adopted in this paper can better realize the early warning of batteries TR, which is of great importance in ensuring the safety of people's lives and property.