Abstract
We report on a unique safety mechanism introduced to the Li-ion battery design to mitigate the effects of a mechanical impact event by limiting the current moving through resulting internal shorts, thereby preventing thermal runaway. “Slitted” electrodes and current collectors would electrically isolate the impacted parts of the electrodes before puncturing the separator. Batteries with such “slitted” electrodes were shown to perform normally prior to the mechanical impact. A proof-of-concept experiment showed that the battery with modified electrodes survived significant mechanical deformation without any change in the open-circuit voltage of the battery. It is interesting to note that, after the impact event, the modified battery was still viable with a reversible capacity of about 93% of that before the indentation test, while the standard battery was no longer functional.
