摘要
锂电池更好的循环性能和安全性能是电动汽车获得更广泛市场优势的迫切需要,深入了解电解液退浸润的形成机理是长寿命电池发展的关键。该文采用一种超声无损检测方法,从两个维度对市面上常用的3种包装类型的锂离子电池在使用过程中内部电解液发生的变化进行了研究。结果发现:在长度方向,极耳附近相比其他位置更容易出现电解液退浸润的情况,且正极比负极更容易出现退浸润缺陷;厚度方向上电池中间层比外层区域更容易出现退浸润现象。分析发现,这主要是由于电池材料选取与结构设计导致极耳位置具有更高的电流密度和温度,电解液发生反应消耗,加快了此区域的老化进程。最后针对这一现象对未来电池选材与设计和锂电池的发展给出了建议。
To gain a broader market advantage for electric vehicles,it is imperative to enhance the cycle performance and safety of lithium batteries.Understanding the mechanisms of electrolyte deple⁃tion is crucial for developing durable batteries.This study employs ultrasonic non-destructive testing to investigate changes in the internal electrolyte during battery usage.The study focuses on three com⁃mon types of lithium-ion battery packaging available on the market:hard-shell cells,soft pack cells,and cylindrical cells.These changes were examined in detail in both the length and thickness directions.The results indicate that,regardless of whether high or low current is used for charging and discharging,all three types of batteries exhibit similar electrolyte depletion characteristics.In the length direction,the area near the electrode tabs is more prone to electrolyte depletion compared to other areas,and the positive electrode is more susceptible to depletion defects than the negative electrode.In the thickness direction,the middle layer of the battery is more prone to depletion than the outer layers.This phenomenon is mainly due to the higher current density near the electrode tabs caused by the electrical properties of the battery materials and structural design.This results in the ar⁃ea near the tabs remaining in a state of overcharge and overdischarge during cycling,accelerating aging in this region.Additionally,the temperature in this region is relatively higher,causing the elec⁃trolyte to react and be consumed,leading to depletion.Through detailed analysis of different battery packaging types,it was found that certain specific features in battery structural design significantly impact electrolyte depletion.Prismatic cells and cylindrical cells,due to their better structural rigidity,demonstrate superior cycle stability under higher currents and harsher usage conditions.In con⁃trast,soft pack cells exhibit relatively poorer cycle performance.This study not only reveals the spa⁃tial distribution patterns and mechanisms of electrolyte depletion but also proposes several targeted recommendations.These include prioritizing materials with lower resistance and higher thermal stability,optimizing the design of electrode tabs to reduce local current density,and improving battery packaging processes to enhance overall thermal management capabilities.By implementing these im⁃provements,it is expected to significantly enhance the performance and lifespan of lithium batteries,thereby advancing the development of the electric vehicle market.In summary,this study provides important theoretical foundations and practical guidance for the design and optimization of lithium ion batteries,laying a solid foundation for the widespread adoption and application of future electric vehicles.
作者
李浩
夏广
姜伟
陆瑞强
刘超
张佳
邓哲
郑志军
LI Hao;XIA Guang;JIANG Wei;LU Rui-qiang;LIU Chao;ZHANG Jia;DENG Zhe;ZHENG Zhi-jun(Guangzhou Customs Technology Center,Guangzhou 510000,China;School of Mechanical and Automotive Engineering,South China University of Technology,Guangzhou 510641,China;TopSound Technology Co.,LTD,Wuxi 214000,China)
出处
《分析测试学报》
北大核心
2025年第2期238-245,共8页
Journal of Instrumental Analysis
基金
国家重点研究发展计划(2022YFF0607201)
广州市科技计划项目(2023A04J1013)
海关总署课题(2022HK062)。
关键词
锂离子电池
超声原位检测
电解液退浸润
形成机理
lithium-ion batteries
in-situ ultrasonic detection
electrolyte reabsorption
forma⁃tion mechanisms
