测试夹具对磷酸铁锂电池循环性能影响  

Effect of Test Fixture on Cycle Performance of Lithium Iron Phosphate Battery

作　　者：王浩 曾涛[1] 刘伯峥 赵李鹏 WANG Hao;ZENG Tao;LIU Bozheng;ZHAO Lipeng(Tianjin Lishen Battery Joint-Stock Co.,Ltd.,Tianjin 300384,China)

机构地区：[1]天津力神电池股份有限公司,天津300384

出　　处：《能源研究与管理》2022年第3期56-62,共7页Energy Research and Management

基　　金：国家重点研发计划项目(2019YFC1907800)。

摘　　要：为分析测试夹具对锂离子电池循环性能的影响,以磷酸铁锂/石墨软包电池为研究对象,对循环失效电池进行直流内阻、交流阻抗、微分容量无损分析,并将电池拆解出的正负极片和隔膜进行扫描电镜-能谱、X射线衍射、差示扫描量热、透气性分析。研究表明,相比于不限位夹具,使用限位夹具测试电池的负极片表面没有明显死区,负极片表面氧、氟、磷元素的质量分数分别降低1.0%、4.0%和2.2%,LiC6/LiC12峰强比更大,固体电解质界面膜分解热降低35%,隔膜透气性提升4.2%,电池的欧姆内阻降低20%以上。限位夹具不易变形,能够提高电池的受力均匀性,改善电池中的正负极片的界面接触,从而减少电池在充放电过程中副反应的发生,提高电池的循环性能。该结果对于提高模组中单体电池的受力均匀性、提升模组寿命具有指导意义。In order to analyze the influence of test fixture on the cycle performance of lithium-ion battery,taking lithium iron phosphate/graphite pouch cell as research object,the direct current internal resistance,electrochemical impedance spectroscopy,differential capacity were non-invasive analyzed using the cycle failed cells,scanning electron microscope-energy dispersive spectrometer,X-Ray diffraction,differential scanning calorimetry,and permeability were carried out by cathode,anode,and separator disassembled from the cycle failed cells.The research shows that compared with the unlimited fixture,there is no obvious dead zone on the surface of the anode electrode of the cell tested with the limited fixture,the mass fraction of oxygen,fluorine,and phosphorus on the surface of the anode electrode is reduced by 1.0%,4.0%,and 2.2%respectively,the ratio of LiC6/LiC12 peak intensity is stronger,the decomposition heat of solid electrolyte interface film is reduced by 35%,the permeability of the separator is improved by 4.2%,and the ohmic internal resistance of the cell is reduced by more than 20%.The limited fixture is not easy to deform,which can improve the force uniformity of the cell and the interface contact of the cathode and anode plates in the cell,so as to reduce the occurrence of side reactions in the process of charging and discharging and improve the cycle performance of the cell.The results have guiding significance for improving the force uniformity of the single cell in the module and the service life of the module.

关 键 词：测试夹具 循环性能 副反应 界面接触 磷酸铁锂 

分 类 号：TK012[动力工程及工程热物理]