Investigating thermal runaway dynamics and integrated safety mechanisms of micro-batteries using high-speed X-ray imaging

Prevention and mitigation of hazardous battery failure scenarios can be achieved through the integration of different safety systems. These mechanisms are routinely evaluated post-testing in a static fashion but lack insights to their dynamic behavior. However, thanks to fast X-ray imaging one can assess the function of these safety mechanisms in-situ. In this work, micro batteries equipped with a combined venting and current interruption mechanism have been subjected to abuse testing in combination with synchrotron high-speed X-ray imaging. Acquired radiography reveals that the current interrupting system was not always activated as described by the manufacturer, and thus provides insights into potential improvements of the system. In addition, the cell was tested in a different configuration where this mechanism was impeded and we conclude that in-situ visualization with X-ray imaging is a crucial tool for validation of safety mechanisms integrated into batteries.