锂电池极片辊压工艺变形分析

Rolling Deformation of Lithium Battery Electrode

目的减小锂离子电池正负极片厚度的不一致性。方法以锂离子电池正负极片辊压工艺为研究对象,通过理论分析的方法,针对不同压力、不同截面的压辊在工艺变形过程中的挠曲变形和弹性变形进行探讨,并分析不同变形对极片厚度不一致性的影响。同时,对在企业中广泛应用的热压工艺进行分析。结果正负极片在不同压力下均会发生挠曲变形和弹性变形,前者增加了厚度不一致性,随着压力的增加,挠曲变形程度增大;在辊压工艺中,尽量将极片中心线和压辊中心线对齐,两者有偏移会增加挠曲变形,从而增加极片厚度的不一致性,两者偏移距离越大,挠曲变形也随着增加;此外,压辊直径、压辊弹性模量,以及极片宽度等因素也会影响挠曲变形。结论辊压工艺中,可以从压辊角度进一步提高极片厚度的均匀性。

The paper aims to reduce the thickness inconsistency of positive and negative electrodes of lithium ion batteries. The rolling process on anode and cathode electrode of lithium ion battery was studied theoretically. The flexure deformation and elastic deformation of roller with different pressure and sections were discussed; and different effects of deformation on the thickness inconsistency were analyzed. The hot-pressing technology which was widely used in enterprises was also analyzed. The flexure deformation of positive and negative electrodes under different pressure would increase the thickness inconsistency, while elastic deformation would not. With the increase of pressure, the degree of deflection of the roller increased. The center line of the roller and that of the electrode should be in a line in rolling. The deviation of them would increase the deflection, and thus lead to thickness inconsistency of the electrode. In addition, the roller diameter, elastic modulus, and the width of the electrode, etc. would affect the flexure deflection. In the rolling process, the thickness uniformity of the electrode can be further improved from the pressing roller.