Abstract：
The safety concerns surrounding lithium-ion batteries (LIBs) have garnered increasing attention due to their potential to endanger lives and incur significant financial losses. However, the origins of battery failures are diverse, presenting significant challenges in developing safety measures to mitigate accidental catastrophes. In this study, the aging mechanism of LiNi0.5Co0.2Mn0.3O2||graphite-based cylindrical 18,650 LIBs stored at room temperature for two years was investigated. It was found that an uneven distribution of electrolytes can be caused by gravity, leading to temperature variations within the battery. Specifically, it was observed that the temperature at the top of the battery was approximately -0.89 °C higher than at the bottom, correlating with an increase in partial internal resistance. Additionally, upon disassembly and analysis of spent batteries, the most significant damage to electrode materials at the top of the battery was observed. These findings suggest that gravity-induced electrolyte insufficiency exacerbates side reactions, particularly at the top of the battery. This study offers a unique perspective on the safety concerns associated with high-energy-density batteries in long-term and large-scale applications.
摘要：
围绕锂离子电池（LIB）的安全问题已引起越来越多的关注，因为它们有可能危及生命并造成重大的经济损失。然而,电池故障的起源是多种多样的，在制定安全措施以减轻意外灾难方面提出了重大挑战。在这项研究中,研究了LiNi0.5Co0.2Mn0.3O2||石墨基圆柱形18,650LIBs在室温下储存两年的老化机理。结果发现，电解质的不均匀分布可能是由重力引起的，导致电池内的温度变化。具体来说,观察到电池顶部的温度比底部的温度高约-0.89°C，与部分内部电阻的增加有关。此外,在拆卸和分析废电池后，观察到对电池顶部电极材料的最显著损坏。这些发现表明，重力引起的电解质不足会加剧副反应，特别是在电池的顶部。这项研究为长期和大规模应用中与高能量密度电池相关的安全问题提供了独特的视角。
