软包磷酸铁锂电池高温浮充后的电化学性能  

Electrochemical Properties of Soft-pack LiFePO4 Battery after High-temperature Float Charge

作　　者：韦守李 尹涛 贾隆舟 常修亮 王敬豪 戴作强[1,2,3] 李希超 郑莉莉 WEI Shouli;YIN Tao;JIA Longzhou;CHANG Xiuliang;WANG Jinghao;DAI Zuoqiang;LI Xichao;ZHENG Lili(College of Mechanical and Electrical Engineering,Qingdao University,Qingdao 266071;Power Integration and Energy Storage System Engineering Technology Center of Qingdao University,Qingdao 266071;National and Local Joint Engineering Technology Center for Intelligent Power Integration Technology of Electric Vehicles,Qingdao University,Qingdao 266071)

机构地区：[1]青岛大学机电工程学院,青岛266071 [2]青岛大学动力集成及储能系统工程技术中心,青岛266071 [3]青岛大学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266071

出　　处：《电气工程学报》2024年第2期297-306,共10页Journal of Electrical Engineering

基　　金：电动汽车储电系统(储能电池)-电(动力电池/超级电池)耦合成组技术研究资助项目(40518060027)。

摘　　要：磷酸铁锂电池因其较好的安全性在储能领域中备受关注。浮充电是一种对电池进行能量补充的常用充电方式,研究不同浮充条件对电池性能的影响显得尤为重要。以额定容量21 A·h的软包磷酸铁锂电池为试验对象,进行高温(50℃)浮充试验,探究高温下不同浮充电压(3.40 V、3.65 V、3.85 V)对电池容量、放电倍率性能、温度场分布和混合功率脉冲特性等性能的影响。结果发现,浮充后电池容量保持率急剧衰减,60天后的容量保持率均低于80%,并随着浮充电压升高,其容量保持率加剧递减,高温下浮充电压差异带来的影响明显增大。高温浮充后电池活性材料和活性锂离子损失严重,界面反应动力学受到阻碍,电池内阻明显增加,且电池放电脉冲功率能力减小,这些老化随浮充电压的升高而加快。温度场分布研究表明,高温浮充后电池放电时最高温度出现在正极极耳处,同时电池放电倍率能力在浮充后明显衰减,并随倍率增大放电容量缩减,且对应点温升明显加剧。由于电池高温浮充后会出现的老化和温升现象,因此电池在使用中应当避免长期高温浮充。本文为磷酸铁锂储能电池的浮充策略提供一定的参考依据。LiFePO4 battery has attracted much attention in the field of energy storage due to their safety.Floate-charging is a common charging method to supplement battery energy.It is particularly important to study the influence of different floate-charging conditions on battery performance.In this paper,the high-temperature(50℃)float-charging test is carried out on the soft-pack LiFePO4 battery with the rated capacity of 21 A·h,to explore the influence of different float-charging voltages(3.40 V,3.65 V and 3.85 V)on the battery capacity,discharge rate performance,temperature field distribution,mixed power pulse characteristics and other performance under high-temperature.The results show that after float-charging,the capacity retention rate of the battery decreased sharply,and the capacity retention rate is lower than 80%after 60 days.With the increase of float-charging voltage,the capacity retention rate decreased sharply,and the influence of float-charging voltage difference at high-temperature increased significantly.After the high-temperature float-charging,the active materials and active lithium ions of the battery are seriously lost,the kinetics of the interface reaction is hindered,the internal resistance of the battery increases significantly,and the battery discharge pulse power capacity decreases.These aging phenomena accelerated with the increase of float-charging voltage.The research on temperature field distribution shows that the highest temperature of the battery during discharge occurs at the positive electrode lug after high-temperature float-charging.At the same time,the battery discharge rate capacity decreases significantly after float-charging,and the discharge capacity decreases with the increase of the rate,and the temperature rise at the corresponding point increases significantly.Due to the aging and temperature rise of the battery after high-temperature float-charging,long-term high-temperature float-charging should be avoided in the use of the battery.A reference for the floate-charging str

关 键 词：浮充电 磷酸铁锂电池 不同电压 电化学性能 

分 类 号：TM911[电气工程—电力电子与电力传动]