A deterministic approach to achieving repeatable sidewall rupture failure modes within lithium-ion thermal abuse studies

Sidewall rupture is among the most violent and destructive ways a lithium-ion cell can fail during a thermal runaway event. When individual cells are aggregated into a complete system there is a high risk of catastrophic propagation. Developing methods to reliably initiate this failure mode will allow deterministic study of appropriate mitigation materials to contain or prevent it. Comprehensive results identified sidewall ruptures were reliably initiated by three primary factors: heating location across a central band of the cell, high heating rates, and restricted positive cell vents. Application of all three factors allowed consistent massive sidewall tears in all thermal abuse experiments. Additionally, for the first time we show a means of directing the failure at a specified position on the cell casing via a simple scoring approach down the sidewall. These results are critical for informing the repeatability of results and the quality of data gathered by allowing data gathering sources to be focused on the point of rupture. • Thermal abuse was initiated via a heating coil on commercial lithium-ion cells. • Different failure modes have been reliably triggered, including sidewall rupture. • Appropriate variables for failure mode scenarios identified. • Novel weakened sidewall approach for directional failure developed.