电解质杂质和SEI组成对电池安全的影响
Florian Baakes1, Daniel Witt1, Ulrike Krewer1
1Institute for Applied Materials - Electrochemical Technologies, Karlsruhe Institute of Technology Adenauerring 20b 76131 Karlsruhe Germany ulrike.krewer@kit.edu.
Chemical science
|December 11, 2023
概括
一个新的热逃跑模型显示,由于更厚的固体电解质介相 (SEI) 层,老化的离子电池更安全. 电极中的水杂质增加了热失控风险,这与预期相反.
科学领域:
- 材料科学 材料科学 材料科学
- 化学工程是化学工程的重要组成部分.
- 电化学 电化学 电化学
背景情况:
- 离子电池面临热失控风险,目前的安全评估仅限于实验或半经验方法.
- 更深入地了解热失控触发器以及化学物种和杂质的影响,对于全面的安全评估至关重要.
- 现有的方法阻碍了通过设计或操作来优化安全对策.
研究的目的:
- 为离子电池开发一个详细的热逃逸模型.
- 调查化学物种和杂质,特别是水和固体电解质相间 (SEI) 特性对热失控的影响.
- 提高对电池老化对安全影响的理解.
主要方法:
- 开发一种包含详细降解反应网络的新型热逃逸模型.
- 模拟水杂质和不同的SEI特性 (组成和厚度) 对电池安全的影响.
- 模型预测与老旧和新鲜电池的实验数据的比较.
主要成果:
- 该模型准确地复制了实验观察结果,显示老化的细胞在15-20°C的温度下表现出自加热,比新鲜细胞更高.
- 老细胞中较厚,无机且反应较弱的SEI层被确定为安全性增加的原因.
- 广泛的电极干燥以去除水中的杂质并不能显著提高安全性;相反,未干燥的电极表现出更早的自我加热,表明更高的热失控风险.
结论:
- 该研究提供了对影响离子电池热失控灵敏度的因素的关键见解.
- 电池安全受到SEI属性的重大影响,SEI属性在老化过程中发生变化.
- 在生产过程中控制SEI属性,并根据老化影响调整安全评估是防止热失控的关键.
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