Analysis of kerf quality on ultrafast laser cutting of anode material for lithium-ion battery

The service performance of lithium-ion battery is greatly affected by the cutting quality of sandwich structure electrode materials. Based on the ultrafast laser cutting experimental system, the ultrafast laser cutting processing parameters of anode material were studied, the processing ability of ultrafast laser on anode material was preliminary showed by the maximum single-scan velocity. The depth, heat affected zone (HAZ) and delamination width of anode kerf were characterized by 3D digital microscope and scanning electron microscope (SEM). It is revealed that kerf depth is a piecewise function of laser power and the ultrafast laser cutting process of anode is dominated by the copper foil. Raman analysis of anode active material shows that the ordered graphite structure is partially damaged in the color-changed zone near kerf edge, providing insight into characterization of HAZ. Kerf characteristics indicate that HAZ and delamination were resulted from heat accumulation, while analysis of anode plasma spectra shows potential impacts of plasma thermal radiation on the defects of anode. When anode material was completely penetrated with single-scan laser exposure, the HAZ size and delamination width of anode material increase with laser power and pulse width. Delamination of anode was completely eliminated by multi-scan ultrafast laser cutting at low laser power and high scanning speed.