长寿命循环的磷酸铁锂电池及材料、工艺

Long life lithium iron phosphate battery and its materials and process

利用预锂化技术以及预锂化材料(也称为补锂剂、预锂化添加剂)的富锂优势,将预锂化材料添加在磷酸铁锂(LFP)电池正极极片中,研制了磷酸铁锂方形铝壳51 Ah全电池,以及软包7 Ah全电池,并进行了循环寿命方面的测试和研究。利用以往经验分析了正极、负极等主材(比如磷酸铁锂、石墨、电解液配比、集流体、隔膜)到辅料(正、负极黏合剂,导电剂等)以及预锂化材料的特性和对电池寿命的影响,以化学反应方程式的形式分析了已经工业化的几种预锂化材料的补锂机理以及补锂容量值。试验结果表明,添加预锂化材料的7 Ah电池循环寿命在9000周,而没有添加预锂化材料的7 Ah电池的循环寿命在5300周,添加预锂化材料的7 Ah电池的循环性能明显优于未添加预锂化材料的电池,循环寿命提高了50%左右;能量效率方面:添加预锂化材料的7 Ah电池的常温25℃,0.2 C能量转化效率为96.74%,0.5 C能量转化效率为94.80%,1 C能量转化效率为92.67%,均高于未添加预锂化材料的7 Ah电池的能量转化效率。本研究有助于推动预锂化技术以及预锂化材料在磷酸铁锂长循环新型储能电池中的应用,为长寿命磷酸铁锂电池的设计研发提供实验依据。

This study focuses on harnessing the advantages of prelithiation technology and prelithiation materials,also known as lithium supplements or prelithiation additives,by incorporating them into the positive electrode of lithium iron phosphate(LFP) batteries.Two battery prototypes were developed:A 51-Ah square aluminum-shell full battery with LFP and a 7-Ah soft-pack full battery.The cycle life of these batteries was tested and studied.Based on experience,the characteristics and impact on the battery life of main materials such as positive and negative electrodes(such as LFP,graphite,electrolyte ratio,current collector,and separator),auxiliary materials(positive and negative electrode adhesives,conductive agents,etc.),and prelithiation materials were analyzed.The lithium replenishment mechanism and lithium replenishment capacity of several prelithiation materials that have already been industrialized were analyzed through chemical reaction equations.Experimental results show that the cycle life of a 7 Ah battery with prelithiated materials reaches 9000 cycles,while a 7 Ah battery without prelithiated materials achieved 5300 cycles.The 7 Ah battery with prelithiated materials exhibits substantially better cycle performance compared to that without prelithiated materials,with a cycle life increase of over 50%.In terms of energy efficiency,the 7 Ah battery with prelithiated materials at 25 ℃ demonstrates an energy efficiency of 96.74% at 0.2 C,94.80% at 0.5 C,and 92.67%at 1 C,surpassing the energy conversion efficiency of a 7 Ah battery without prelithiation materials.This research promotes the application of prelithiation technology and materials in long-cycle new energy storage LFP batteries.It provides an experimental basis and guidance for the design and development of long-life LFP batteries,thereby contributing to the advancement of energy storage systems.