Experimental Investigation of Factors Influencing Thermal Runaway in Lithium-Ion Battery Cells

Experimental testing in automotive development sometimes relies on ad hoc approaches like ‘One Factor at a Time’, particularly in time- and resource-limited situations. While widely used, these approaches are limited in their ability to systematically capture parameter interactions and system complexities, which poses significant challenges in safety-critical applications like high-voltage battery systems. This study systematically investigates the factors influencing thermal runaway in lithium-ion battery cells using a statistical full-factorial experimental design. Key parameters, including state of charge, cell capacity and heating trigger power, have been analyzed under controlled conditions with an autoclave setup, enabling precise measurement of thermal and mechanical responses. The use of automotive-grade lithium-ion cells ensures relevance for next-generation applications. By employing factorial regression and statistical analysis, the study identifies critical temperatures, gas evolution rates, and energy release mechanisms during thermal runaway. The results highlight the dominant influence of the state of charge on the severity and onset of thermal events. These findings underscore the necessity of comprehensive testing strategies to improve the safety and reliability of high-energy battery systems. This work advances understanding of thermal instability in lithium-ion cells and provides actionable insights for mitigating risks through design optimization. Future research will explore enhanced thermal management strategies to further reduce battery failure risks in applications like electric vehicles.