锂电池铝箔断带成因及控制机制研究

Study on the cause and control mechanism of aluminum foil breakage in lithium battery

本文针对锂电池正极极片辊压及其所用铸轧供坯的铝箔生产过程中的断带成因及其机制进行了研究,通过OM、EBSD、TEM、SEM及EDS等对电池铝箔的微观组织和断带缺陷进行分析.结果表明:大变形后电池铝箔的纳米晶组织和位错塞积特征导致晶粒在继续变形时协调性变差,倾向于脆性断裂.通过添加合金元素、合理匹配铝箔加工率和退火工艺制度,提高强度的同时增加韧性,可以减少断带频率;电池铝箔涂布材料均匀、辊压工艺参数与电池铝箔性能的匹配优化可以减少辊压断带频率;控制电池铝箔坯料冶金质量、保持稳定的卷取张力避免铝卷层间划伤,同时保持生产过程中的洁净环境,精细化切边工艺和设备,可降低电池铝箔断带的可能性.

The cause and mechanism of breakage were studied during the rolling process of lithium battery positive electrode and production of aluminum foil from casting and rolling blank.The microstructure and defects of breakage were analyzed by OM,EBSD,TEM,SEM and EDS.The results show that the nanocrystalline structure of the battery aluminum foil after severe deformation and the dislocation pile-up feature lead to the poor coordination of the grains during continuous deformation,which is more prone to brittle fracture.By adding alloy elements and reasonably matching the aluminum foil processing rate and annealing process system,the strength and toughness can be increased at the same time,and the frequency of breakage is reduced.Uniformity of battery foil coating material,matching optimization of rolling process parameters and battery foil performance can reduce rolling breakage.The possibility of battery aluminum foil breakage can be reduced by controlling the metallurgical quality of battery aluminum foil blank,maintaining a stable coiling tension to avoid scratches between layers of coils,maintaining a clean environment in the production process,and refining the trimming process and equipment.