Characteristics of combustible gases during the thermal runaway of lithium-ion batteries in a large-scale cabin

In this study, a set of experiments were conducted in a large-scale battery cabin to investigate the characteristics of combustible gases during the thermal runaway of lithium-ion batteries caused by the external overheating. The composition and distribution of the gases were analyzed and discussed. Results showed that the spread rate of the gases was very fast and it took only 1 minute to fill the whole battery cabin. The hydrogen in the battery pack was detected earlier than the carbon monoxide. Although the former content was lower than the carbon monoxide, the propagation time reached the cabin roof was shorter due to a lower density of hydrogen. In contrast to the hydrogen and carbon monoxide, the carbon dioxide was suggested to be used as one of the characteristic gases for the thermal runaway monitoring and early warning. This was more advantages in cost and service life than the hydrogen.