Preventing Li-ion cell explosion during thermal runaway with reduced pressure

Highlights: • Increase of Li-ion cell safety by reduced pressure. • Li-ion cell thermal runaway without cell explosion. • Reduced pressure via vacuum pump or suction unit. - Abstract: Concerning Li-ion cells it is demonstrated by overcharging tests both on the shelf in a fume-hood and in an accelerating rate calorimeter that the application of reduced pressure in the moment of a thermal runaway accident can prevent a fire and in particular a cell explosion, caused by the electrolyte. Within the experiment, pouch-bag Li-ion cells (88 mAh and 264 mAh) composed of graphite and NMC (LiNi_1/3Mn_1/3Co_1/3O₂) were overcharged by 10 C in order to induce a thermal runaway. In spite of a strong temperature increase, the cell remains tightly close during the thermal runaway without any fire or explosion in case of vacuum application.