储能科学与技术 ›› 2022, Vol. 11 ›› Issue (12): 3978-3986.doi: 10.19799/j.cnki.2095-4239.2022.0405

• 储能测试与评价 • 上一篇    下一篇

过充循环对锂离子电池容量衰减及安全性影响

许卓1,2,3(), 李希超1,2,3, 贾隆舟1,2,3, 陈兵1,2,3, 戴作强1,2,3(), 郑莉莉1,2,3   

  1. 1.青岛大学机电工程学院
    2.青岛大学动力集成及储能系统工程技术中心
    3.电动汽车智能化动力集成技术国家地方联合工程技术中心(青岛),山东 青岛  266071
  • 收稿日期:2022-07-18 修回日期:2022-08-23 出版日期:2022-12-05 发布日期:2022-12-29
  • 通讯作者: 戴作强 E-mail:xuzhuoxz@163.com;daizuoqiangqdu@163.com
  • 作者简介:许卓(1998—),女,硕士研究生,主要研究方向为新能源电动汽车,E-mail:xuzhuoxz@163.com
  • 基金资助:
    电动汽车储电系统电(储能电池)-电(动力电池/超级电容)耦合成组技术研究(40518060027)

Effect of overcharge cycle on capacity attenuation and safety of lithium-ion batteries

Zhuo XU1,2,3(), Xichao LI1,2,3, Longzhou JIA1,2,3, Bing CHEN1,2,3, Zuoqiang DAI1,2,3(), Lili ZHENG1,2,3   

  1. 1.College of Mechanical and Electrical Engineering
    2.Engineering Technology Center of Power Integration and Energy Storage System, Qingdao University
    3.National and Local Joint Engineering Technology Center for Intelligent Power Integration Technology for Electric Vehicles (Qingdao), Qingdao 266071, Shandong, China
  • Received:2022-07-18 Revised:2022-08-23 Online:2022-12-05 Published:2022-12-29
  • Contact: Zuoqiang DAI E-mail:xuzhuoxz@163.com;daizuoqiangqdu@163.com

摘要:

随着能源问题的出现,锂离子电池已成为人们关注的热点。本工作以18650型NCM811锂离子电池为研究对象,将电池过充至3个不同的截止电压(4.3 V、4.4 V、4.5 V)并循环一定的次数(180次)直到电池容量大幅度衰减,基于测试分析4.5 V过充循环电池的交流阻抗谱和容量增量曲线来定性和定量地研究电池容量衰减机理。研究发现活性锂离子的损失和活性材料的损失是电池容量衰减的主要原因,电池电导率的损失对电池容量衰减影响不大。通过绝热加速量热仪(adiabatic rate calorimeter,ARC)研究新电池,4.3 V、4.4 V和4.5 V过充循环电池在100% SOC下的热失控特征参数(自产热起始温度T1、热失控触发温度T2、热失控最高温度T3)。发现在热失控发生过程中,电池达到相同的温度时,4个电池的温升速率大小分别是新电池<4.3 V过充循环电池<4.4 V过充循环电池<4.5 V过充循环电池。电池在经过过充循环之后热稳定性变差。过充循环后,电池的自产热起始温度降低、热失控触发温度降低。

关键词: 锂离子电池, 过充循环, 电化学阻抗谱, 热失控

Abstract:

Lithium-ion batteries have become a hot spot with the emergence of energy problems. This study takes the 18650 NCM811 lithium-ion battery as the research object. It overcharges the battery to three different cut-off voltages (4.3 V, 4.4 V, and 4.5 V) and cycles it several times (180 times) until the battery capacity decays significantly. The test and analysis of the 4.5 V overcharged circulating battery's AC impedance spectrum and capacity increment curve reveal the mechanism of battery capacity decay, which is studied both qualitatively and quantitatively. It was discovered that the main cause of battery capacity attenuation is the loss of active lithium ions and active materials, whereas the loss of battery conductivity has little effect. The thermal runaway characteristic parameters (self-heating starting temperature T1, thermal runaway triggering temperature T2, maximum thermal runaway temperature T3) of new batteries, 4.3 V, 4.4 V, and 4.5 V, overcharged circulating batteries at 100% SOC, which was investigated by adiabatic rate calorimeter. It was found that in the thermal runaway process when the battery reached the same temperature, the temperature rise rates of the four batteries were new battery<4.3 V overcharge cycle battery<4.4 V overcharge cycle battery<4.5 V overcharge cycle battery, respectively. The thermal stability of the battery becomes worse after the overcharge cycle. After the overcharge cycle, the starting temperature of the self-generated heat of the battery decreases. In addition, the trigger temperature of the thermal runaway decreases.

Key words: lithium ion battery, overcharge cycling, electrochemical impedance spectroscopy, thermal runaway

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