锂离子电池安全检测传感器研究进展

近年来, 由于热失控引发的锂离子电池安全事故频繁发生, 严重影响了新能源汽车运行安全, 作为保障车辆运行安全的有效手段, 对电池系统进行安全检测尤为重要。为提高锂离子电池的性能、延长循环寿命, 减少热失控安全事故的发生, 需要利用传感器技术对电池工作状态进行实时监控和检测。根据电池正常和异常工作状态下各物理量的变化, 常用的安全检测信号有应力应变、温度以及特征气体等。目前, 用于检测上述信号的安全检测传感器在电池状态检测方面已得到了广泛的应用。然而, 传统的传感器存在着体积大、灵敏度低、不耐电解液腐蚀等问题。对新型光纤布拉格光栅传感器、柔性薄膜传感器以及半导体式气体传感器的工作原理进行概述, 总结了上述3种传感器在锂离子电池应力应变、温度和气体检测的应用现状, 并从稳定性以及灵敏度等角度指出当前研究的不足, 如光纤布拉格光栅传感器电池体系适用性差, 插入式薄膜传感器影响电池性能, 半导体气体传感器精度和寿命低等问题。如何以经济、安全和实用的方式将传感器安装到电芯中, 减轻实际应用中传感器对电池循环性能的影响以及提高传感器信号传递的稳定性、精度、灵敏度, 是锂离子电池安全传感器开发面临的挑战, 仍然需要在传感器、电池设计等方面开展大量实验研究。

An Overview on Research Progress of Sensors for Detecting Safety of Lithium Batteries

In recent years, due to the frequent occurrence of lithium-battery accidents caused by thermal runaways, it is particularly important to apply the battery-safety monitoring systems. To improve the performance, extend the cycle life of lithium batteries and avoid the occurrence of those accidents, it is necessary to use sensor technique to monitor the working states of batteries in real-time. Based on the changes of physical variables in the batteries' working states, the commonly used safety detection signals include stress-strain, temperature, and gas. At present, safety-detection sensors for monitoring the signals are widely used in battery-state detection system. However, traditional sensors have some disadvantages, such as large volume, low sensitivity, and poor resistance to electrolytic corrosion. After outlining the working principles of the new fiber Bragg grating sensor, flexible film sensor and semi-conducting gas sensor, this paper summarizes the applications of the above three sensors in detecting stress-strain, temperature, and gas, and discusses the shortcomings of current studies from the perspectives of stability and sensitivity.The shortcomings include the poor applicability of the fiber Bragg grating sensor, the negative impact of the flexible film sensor on battery performance, and the low accuracy and short life of the semi-conducting gas sensor. The questions how to install the sensors into the battery cells in an economical, safe and practical way, how to reduce the influence of the sensors on the cycle performance of batteries in practice, and how to improve the stability, accuracy and sensitivity of sensor-signal transmission are crucial for the development of sensors for safety detection system of lithium-battery, which still need massive research on the sensor and battery design.