Influence of vibration on cyclic and thermal runaway characteristics of lithium ion batteries

By analyzing the impact of mechanical vibration on the safety of lithium ion batteries in various application scenarios, such as transportation and aerospace, the 18650 battery was used as a sample, and the.influence of vibration conditions on the internal structure, cyclic aging mechanism, electrical performance, and thermal runaway characteristics of lithium ion batteries was investigated. The results indicate that vibration can significantly induce alterations in the internal microstructure of lithium ion batteries. Prolonged exposure to vibration stress can lead to deformation of the negative electrode collector, resulting in compression on the electrode roll. Additionally, momentary vibration stress can dynamically affect the contact area between the electrode material and the diaphragm, impeding the migration of lithium ions during the embedding and de-embedding processes. Consequently, this exacerbates the fluctuation of Coulomb efficiency and energy efficiency, leading to insufficient discharge under vibration conditions. Furthermore, thermal runaway experiments demonstrate that the time required to trigger thermal runaway shortens as the duration of vibration increases. Compared with that of non-vibrating batteries, the initial explosion time of thermal runaway of batteries subjected to 600 hours of vibration shortens to 72 seconds, and the combustion-induced explosion time shortens to 114 seconds. Meanwhile, the interval between initial and combustion-induced explosions is shortened. Moreover, the instability of the impact force produced by combustion-induced explosion increases.