WMG, University of Warwick, Coventry, CV4 7AL, United Kingdom.
Hybrids and Electrification, Jaguar and Land Rover, Banbury Road, Warwick, CV35 0XJ, United Kingdom.
Sci Rep. 2017 Jul 11;7(1):5128. doi: 10.1038/s41598-017-05438-2.
In freight classification, lithium-ion batteries are classed as dangerous goods and are therefore subject to stringent regulations and guidelines for certification for safe transport. One such guideline is the requirement for batteries to be at a state of charge of 30%. Under such conditions, a significant amount of the battery's energy is stored; in the event of mismanagement, or indeed an airside incident, this energy can lead to ignition and a fire. In this work, we investigate the effect on the battery of removing 99.1% of the total stored energy. The performance of 8Ah C/LiFePO pouch cells were measured following periods of calendar ageing at low voltages, at and well below the manufacturer's recommended value. Battery degradation was monitored using impedance spectroscopy and capacity tests; the results show that the cells stored at 2.3 V exhibited no change in cell capacity after 90 days; resistance rise was negligible. Energy-dispersive X-ray spectroscopy results indicate that there was no significant copper dissolution. To test the safety of the batteries at low voltages, external short-circuit tests were performed on the cells. While the cells discharged to 2.3 V only exhibited a surface temperature rise of 6 °C, cells at higher voltages exhibited sparks, fumes and fire.
在货运分类中，锂离子电池被归类为危险品，因此需要严格遵守认证安全运输的规定和准则。其中一项准则是要求电池的电量处于 30%的状态。在这种情况下，电池储存了大量的能量；如果管理不善，或者确实发生了机场事件，这些能量可能会导致点火和火灾。在这项工作中，我们研究了去除电池总储存能量的 99.1%对电池的影响。在低于制造商建议值的低电压下，对 8Ah C/LiFePO 软包电池进行了日历老化周期的性能测试。使用阻抗谱和容量测试监测电池退化情况；结果表明，在 2.3V 下储存的电池在 90 天后电池容量没有变化，电阻上升可以忽略不计。能量色散 X 射线光谱结果表明，没有明显的铜溶解。为了测试电池在低电压下的安全性，对电池进行了外部短路测试。虽然电池放电至 2.3V 时仅显示表面温度升高 6°C，但在较高电压下的电池则会出现火花、烟雾和火灾。
