极卷起皱对锂离子电池安全性能的影响

Effect of jellyroll wrinkles on the safety performance of Li-ion battery

用绝热加速量热(ARC)分析13530215型锂离子电池充放电过程的温升,用差示扫描量热(DSC)分析正极、负极和电解液的热稳定性。用SEM、X射线光电子能谱(XPS)研究负极表面形貌和组成以及固体电解质相界面(SEI)膜的厚度,用气相色谱-质谱(GC-MS)研究电解液有机溶剂的组成。与新电池相比,循环500次后的电池充电温升增加41%,放电温升增加86%,安全性变差。在电池使用过程中,负极起皱区域附近表面会出现脱料、析锂现象,析锂又会导致负极表面类SEI产物增多和电解液变质,使负极和电解液的热稳定性下降,增加电池的安全隐患。

The temperature rise of 13530215 type Li-ion battery during charge-discharge process was studied using adiabatic rate calorimeter(ARC).The thermal stability of anode,cathode and electrolyte was studied using differential scanning calorimetry(DSC).The morphology and composition of anode surface and thickness of solid electrolyte interface(SEI)film were studied using SEM and X-ray photoelectron spectroscopy(XPS).The composition of organic solvents in electrolyte was tested using gas chromatography mass spectrometry(GC-MS).After cycled 500 times,the temperature rise of battery during charge and discharge was increased by 41%and 86%separately,compared with fresh battery,the safety performance was deteriorated.The jellyroll wrinkles brought about striping and lithium plating during using,so that SEI film-like products on anode increased and electrolyte deteriorated,thereby the thermal stability of cathode and electrolyte reduced,which increased the safety hazards of the battery.