曲折度法检测锂离子电池的电解液浸润性  

Electrolyte wettability detection of Li-ion battery by tortuosity method

作　　者：李丽娟 宋林霏 朱振东 LI Lijuan;SONG Linfei;ZHU Zhendong(Hefei Gotion High-Tech Power Energy Co.,Ltd.,Hefei 230012,Anhui,China)

机构地区：[1]合肥国轩高科动力能源有限公司,安徽合肥230012

出　　处：《电池》2025年第2期303-306,共4页Battery Bimonthly

摘　　要：在锂离子电池电芯量产中,电解液对极片的浸润程度和浸润时间极为重要,需要开发一种分析电解液浸润性的方法。分析LiFePO_(4)对称锂离子电池的阻抗谱,评估多孔正极的孔隙阻抗,并计算极片的曲折度,间接验证电解液的浸润性。通过电化学阻抗谱(EIS),监测LiFePO_(4)对称电池注液后不同时间内的阻抗变化,分析从0 min到72 h的浸润时间对孔隙阻抗和曲折度的影响。随着电解液浸润时间的延长(从0 min至72 h),孔隙阻抗从0.0764Ω降至0.0370Ω,曲折度从0.83降至0.40,表明浸润性逐步提高,并在24 h后达到稳定。曲折度可间接衡量电解液的浸润性,当达到稳定值时,电解液已完全浸润极片。该检测方法无损、简便,适用于生产线电解液浸润时间的评估,并可推广至其他活性材料的浸润性分析。The wetting degree and the wetting time of electrodes on the electrode are crucial for the mass production process cells in Li-ion battery.It is necessary to develop a method to analyze the wettability of the electrolyte.The pore impedance of the porous cathode is evaluated by analyzing the impedance spectrum of the LiFePO_(4) symmetrical Li-ion battery and calculating the tortuosity of the electrode,thereby indirectly verifying the electrolyte wettability.The electrochemical impedance spectroscopy(EIS)is used to monitor the impedance changes in LiFePO_(4) symmetrical batteries at different time after electrolyte injection,analyze the effect of wetting time from 0 min to 72 h on pore impedance and tortuosity.With the increase of wetting time(from 0 min to 72 h),the pore impedance is decreased from 0.0764Ωto 0.0370Ω,the tortuosity is decreased from 0.83 to 0.40,indicating that the wettability is gradually improved and stabilized after 24 h.The tortuosity can indirectly characterize the electrolyte wettability.When the tortuosity stabilizes,the electrolyte has fully wetted the electrode.This testing method is non-destructive and simple,suitable for assessing electrolyte wetting time on production lines,and can be extended to characterize the wettability of other active materials.

关 键 词：曲折度 孔隙阻抗 电解液浸润性 锂离子电池 

分 类 号：TM912.9[电气工程—电力电子与电力传动]