不同工况下锂离子电池超声特性分析

Analysis of ultrasonic characteristics of lithium-ion battery under different working conditions

超声信号可以检测电池内部物理性质的变化,通过声学与电化学的耦合,可以了解电池充放电循环期间发生的内部电化学变化规律。电池实际工作时会处于瞬时充电、放电、静置且随机切换的状态,而大部分学者只在标况、常温下进行特定充放电情况下的声学实验,对于实际应用的电池不太现实。基于上述问题,通过搭建磷酸铁锂电池电-声-热综合测试平台,分析了电池在不同工况(不同温度充放电、不同倍率充放电、静置温变、动态工况)下的超声信号变化,观察超声飞行时间和幅值的变化规律,阐述了超声信号在不同工况下的稳定性、灵敏性。在不同工况下的实验结果表明了声学特征表征动态工况的可行性,为未来超声应用于更多电池应用场景的研究奠定了基础。

Ultrasonic signal can detect the changes of internal physical properties of the battery.Through the coupling of acoustics and electrochemistry,we can understand the internal electrochemical changes during the battery charge and discharge cycle.When the battery actually works,it will be in the state of instantaneous charging,discharging,standing and random switching.However,most scholars only do acoustic experiments under specific charging and discharging conditions with standard conditions and normal temperature,which is not realistic for the battery in practical application.Based on the above problems,the ultrasonic signal changes of the battery under different working conditions(charge and discharge tests at different temperatures,charge and discharge tests at different rates,temperature change tests on standing and dynamic working condition test)were analyzed by building a electricalacoustic-thermal comprehensive test platform for lithium iron phosphate battery,the changes of ultrasonic flight time TOF and amplitude SA were observed,and the stability and sensitivity of ultrasonic signals under different working conditions were expounded.The results show the feasibility of characterizing dynamic working conditions by acoustic characteristics,laying a foundation for the research of ultrasonic applying in more battery scenarios in the future.