Remote cutting of Li-ion battery electrodes with infrared and green ns-pulsed fibre lasers

Thin sheet anode and cathode materials made in composite structures constitute some of the most important components of a Li-ion battery. These materials are currently cut by punching technology, which shows degrading behaviour as the tool wears out. A viable option for Li-ion battery electrode manufacturing is the use of remote laser cutting. However, the operation requires fulfilling both productivity and quality aspects to substitute the conventional production method. One of the most critical aspects in quality is the clearance width, which is defined as the extent of the exposed middle layer of the sandwich at the laser cut kerf. This work investigates the quality aspects of laser cutting of Li-ion electrodes when a green fibre laser source (lambda = 532 nm, tau = 1 ns) is used rather than the more traditional infrared (IR) fibre laser source (lambda = 1,064 nm, tau = 250 ns). The processing conditions were investigated to reveal the technological feasibility zones. Clearance width was studied within the technological feasibility zones for all the material-laser combinations. Results showed that high productivity criterion is met by the IR system, since cutting speed could reach 30 m/min with 54 W average laser power on both anode and cathode. On the other hand, the green laser provided clearance width below 20 mu m. In the best case, the clearance on anode could be eliminated with the green laser system. Although the maximum cutting speed was 4.5 m/min, upscaling of green laser power can provide required productivity.