Mei Wenxin, Liu Zhi, Wang Chengdong, Wu Chuang, Liu Yubin, Liu Pengjie, Xia Xudong, Xue Xiaobin, Han Xile, Sun Jinhua, Xiao Gaozhi, Tam Hwa-Yaw, Albert Jacques, Wang Qingsong, Guo Tuan
State Key Laboratory of Fire Science, University of Science and Technology of China, Hefei, 230026, China.
Institute of Photonics Technology, Jinan University, Guangzhou, 511443, China.
Nat Commun. 2023 Aug 29;14(1):5251. doi: 10.1038/s41467-023-40995-3.
Operando monitoring of complex physical and chemical activities inside rechargeable lithium-ion batteries during thermal runaway is critical to understanding thermal runaway mechanisms and giving early warning of safety-related failure. However, most existing sensors cannot survive during such extremely hazardous thermal runaway processes (temperature up to 500 °C accompanied by fire and explosion). To address this, we develop a compact and multifunctional optical fiber sensor (12 mm in length and 125 µm in diameter) capable of insertion into commercial 18650 cells to continuously monitor internal temperature and pressure effects during cell thermal runaway. We observe a stable and reproducible correlation between the cell thermal runaway and the optical response. The sensor's signal shows two internal pressure peaks corresponding to safety venting and initiation of thermal runaway. Further analysis reveals that a scalable solution for predicting imminent thermal runaway is the detection of the abrupt turning range of the differential curves of cell temperature and pressure, which corresponds to an internal transformation between the cell reversible and irreversible reactions. By raising an alert even before safety venting, this new operando measurement tool can provide crucial capabilities in cell safety assessment and warning of thermal runaway.
在热失控过程中对可充电锂离子电池内部复杂的物理和化学活动进行原位监测，对于理解热失控机制以及对与安全相关的故障发出早期预警至关重要。然而，大多数现有传感器在如此极端危险的热失控过程（温度高达500°C并伴有火灾和爆炸）中无法幸存。为了解决这个问题，我们开发了一种紧凑的多功能光纤传感器（长度为12毫米，直径为125微米），能够插入商用18650电池中，以在电池热失控期间连续监测内部温度和压力效应。我们观察到电池热失控与光学响应之间存在稳定且可重复的相关性。传感器的信号显示出两个对应于安全排气和热失控起始的内部压力峰值。进一步分析表明，预测即将发生的热失控的一种可扩展解决方案是检测电池温度和压力微分曲线的突变转折范围，这对应于电池可逆和不可逆反应之间的内部转变。通过在安全排气之前就发出警报，这种新的原位测量工具可以在电池安全评估和热失控预警方面提供关键能力。
