软包电芯外观变形的机理及改善措施研究

Study on mechanism of appearance deformation of pouch cell and its improvement measures

针对软包电芯生产过程中出现外观变形的问题,首先结合电芯的生产制程全过程分析了可能的变形机理,然后针对化成分容工序,提出了减小分容电流、加压分容和满电化成等一系列解决方案,最后展开实验验证。实验结果表明,加热加压满电化成能有效地优化外观不良、减小电芯的堆叠厚度,同时改善界面提高电芯的循环性能。但是满电化成后的老化阶段会消耗活性物质,导致电芯容量下降。因此,在电芯满电化成改进外观后进一步调整降低电芯荷电态,可以减少电芯容量的损耗,从而取得最佳的改善效果。

In order to solve the problem of appearance deformation in the production process of the pouch cell,the possible deformation mechanism in the whole process of the cell production was analyzed,and then a series of solutions were put forward,such as reducing the capacitance current,pressurizing the capacitance and full electrochemical formation.The experimental results show that the heating and pressurization can effectively optimize the bad appearance,reduce the stack thickness of the cell,and improve the interface to enhance the cycle performance of the cell.However,the aging stage after full electrochemical process will consume active substances,resulting in a decrease in cell capacity.Therefore,the loss of cell capacity can be reduced by further adjusting and reducing the charge state of the cell after the cell is fully electrolyzed to improve its appearance,so as to achieve the best improvement effect.