Influence of penetration speeds on power Li-ion-cell’s safety performance

Power-battery safety performance is a key factor in electric vehicle applications. The inner short-circuit is a root cause of battery safety issues, which is usually simulated by nail-penetration tests in the mechanical abuse tests. This paper studies the influence of nail-penetration speeds on the power battery safety performance. Two types of lithium iron phosphate (LFP) ion batteries, cylindrical cells and soft-package cells, were tested referring the standard of Lithium-Ion Batteries for Electric Vehicle for vehicle industries in China. The nail-penetration tests were conducted at different nail-penetration speeds for nails, which can bear high-temperature, with a diameter of 3 mm. The cell voltage and the surface temperature were monitored and analyzed to reflect the influence of different nail speeds on the safety performance. The results show that the nail-penetration speeds have low impact on the cylindrical cells compared with that on the soft-package cells. As for the soft-package cells, the thermal run away becomes more serious with increasing nail speeds.