在快速充电后休息期间,离子电池中存在较大的局部电流
Alec S Ho1,2, Dilworth Y Parkinson3, Stephen E Trask4
1Department of Chemical and Biomolecular Engineering, University of California, Berkeley, California 94720, United States.
ACS nano
|September 19, 2023
概括
静止的离子电池中的内部电流可能会引起火灾. 这项研究量化了快速充电后这些危险的电流,揭示了可能解释电池故障的持续异常值.
科学领域:
- 材料科学 材料科学 材料科学
- 电化学 电化学 电化学
- 电池技术 电池技术
背景情况:
- 电动汽车 (EV) 的快速采用需要先进的离子电池,具有快速充电和增强的安全性.
- 电动汽车电池发生火灾的情况甚至发生在没有主动充电或放电的情况下,这表明休息期间存在风险.
- 电池休息期间的内部离子电流,很难从外部测量,涉及到安全问题.
研究的目的:
- 在快速充电后静止的石墨电极中量化空间解析的内部电流密度分布.
- 调查可能导致电池故障的内部电流的起源和持久性.
- 了解合金,低合石墨和内部离子电流之间的关系.
主要方法:
- 操作式X射线微观断层扫描被用来研究石墨电极.
- 在保持静止之前,电极接受了6C的快速充电.
- 在休息期间量化了空间解析的电流密度分布.
主要成果:
- 在停止充电后20分钟内,平均电流密度从1.5到0.5 mA cm-2下降.
- 观察到内部电流起源于,并以低化石墨颗粒结束.
- 剥离电流密度的范围仍然令人惊地独立于时间,异常值超过20 mA cm-2.
结论:
- 高异常电流密度的持续存在表明,在休息时发生灾难性电池故障的潜在机制.
- 了解这些内部电流对于提高快充离子电池的安全性至关重要.
- 为了更安全的电动汽车电池技术,需要进一步研究减轻这些持续的内部电流.
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