Numerical studies of laser cutting of an anode for lithium-ion batteries

To reduce carbon emission and satisfy strict regulations in an automotive sector, hybrid-electric vehicles have been developed using lithium-ion battery technology due to its superior performance. However, the relatively expensive price of the vehicles is still a critical issue. One reason is high manufacturing cost, especially the cutting process. Currently, the anode cutting process utilizes rotary knives and dies. These require relatively expensive tooling that degrades over time. The degradation results in poor cut quality. This cut quality leads to short circuits and significant heat generation during battery operation. Furthermore, a redesign of mechanical cutting processes demands extra expense due to various cell specifications. Laser cutting provides faster cutting speed, good consistent cut quality, and the possibility of flexible design due to its fast processing time, high precision, and flexible range of laser power. However, these advantages cannot be fully utilized without understanding the underlying physics. A 3D self-consistent mathematical model of anode laser cutting is developed including multiple physical phenomena. This study analyzes temperature and composition distributions, melt pool geometry, and melt pool flow around the interface between copper and graphite. In addition, the effect of these physical properties on the cut quality of an anode is discussed.