A Scenario-Based Theoretical Analysis of the Applicability of Oxygen Consumption Calorimetry-Based Heat Release Measurements for Lithium-Ion Battery Fires Accompanied by Complex Evolved Gases

The importance of heat release evaluation for lithium-ion battery (LIB) fires has increased owing to the widespread adoption of electric vehicles and energy storage systems. However, during thermal runaway, various gases, including CO2, CO, H2, and CH4, as well as internally released oxygen, may be generated, and some flammable gases may be discharged without complete combustion. These characteristics may affect oxygen consumption calorimetry (OCC), which is based on the proportional relationship between atmospheric oxygen consumption and heat release. In this study, a scenario-based theoretical analysis was conducted using time-resolved gas evolution data reported in the literature. The scenarios considered pyrolysis-derived CO2, the participation of flammable gases in combustion, and internally released oxygen. The results indicated that OCC-based heat release calculations may either overestimate or underestimate heat release depending on the characteristics of complex gas evolution. Therefore, the complex gas evolution characteristics of LIB fires were identified as factors that may influence OCC-based heat release evaluation.