锂离子电池湿法PE隔膜生产工艺用白油变色原因

Study on white oil discoloration in wet PE separator production for lithium ion battery

白油是锂离子电池湿法聚乙烯(PE)隔膜生产中的造孔剂。针对白油循环使用过程中油品外观发黄、黄色物质未定性等问题,采用傅里叶变换红外光谱技术研究了模拟生产工艺条件下白油、PE、抗氧化剂1010(I1010)的结构变化与耐黄变性能的关系,以及质量比不同的3种物料混合物的结构变化、耐黄变性能与质量比的关系;采用高效液相色谱和高分辨质谱技术对回收油中黄色物质进行了定性分析。结果表明,白油、PE和I1010在工艺过程中均发生氧化反应,变黄物质的产生是三者协同作用的结果,其中PE和I1010为主要诱因;黄色物质为芳香酯类化合物和I1010。本研究为白油循环使用工艺的改进提供参考。

White oil is used as a pore-forming agent in the production of wet polyethylene(PE)separator for lithium ion battery.In order to explore yellow appearance and yellow substances in white oil recycling processes,Fourier transform infrared spectroscopy was employed to investigate the relationship between structural changes and yellowing resistance of white oil,PE,and antioxidant 1010(I1010)under simulated production conditions.Additionally,the relationship between structure change,yellowing resistance and the ratio of white oil,PE and I1010 mixtures were studied.Furthermore,the yellow substance in recovered oil was qualitatively analyzed using high performance liquid chromatography and high resolution mass spectrometry.The results show that oxidation of white oil,PE,and I1010 occurred in the PE separator production process,and the production of the yellow substance is the results of the synergistic action,in which PE and I1010 are the main factors.The yellow substances were identified as aromatic esters and I1010.This research provides valuable insights for improving white oil recycling technology.