锂电池过充高频振动特性与故障检测装置研制

The safe operation of lithium-ion battery (LIB) is vital to the popularization and application of the electric vehicles. The inconsistency of the cell internal resistance may cause overcharging of a battery cell. The overcharging cell’s continuous charging leads to the thermal runaway and causes fire or explosion accidents. An approach for detecting overcharging fault of the LIB based on the high frequency vibration signals was proposed. Vibration characteristics of the overcharging LIB cell and the battery pack with overcharging cell, and the influence of different overcharging severity and charging current on the LIB surface vibration signal were investigated. The study revealed the generation mechanism of the high frequency vibration when the LIB is overcharged and extracted the overcharging fault detection criterion. The results show that when the LIB is overcharged, the repeated decomposition and regeneration of the solid electrolyte interphase (SEI) film inside the battery and the oxidative decomposition of the electrolyte will release a large amount of gas. As a result, the surface stress of the case changes dramatically and a high-frequency vibration component appears. Meanwhile, the high frequency components of the vibration signals are related to the high frequency components of the charging current. A LIB overcharging fault detection system was developed based on the NI-DAQ and LabVIEW. The detection accuracy is 93. 33% . The system can accurately detect the overcharging fault of the LIB.