Interaction regimes and contaminant-dependent removal mechanisms in nanosecond pulsed laser cleaning of nickel-plated steel battery tabs

As the automotive industry shifts toward e-mobility, laser welding has become essential for joining nickel-plated steel battery tabs; however, process stability is severely compromised by surface contaminants like oils and organic residues. This study investigates nanosecond pulsed laser cleaning as a pre-weld surface preparation method. The process removes contaminants while homogenizing the surface and improving wettability, thereby creating more reliable conditions for welding. To understand the fundamental interaction regimes, controlled contamination methods were applied for both organic residues and industrial oil. The cleaning and melting threshold fluences were experimentally determined. While organic contaminants are removed at lower fluences, oil films exhibit high transparency to the 1064 nm wavelength, requiring substrate-mediated thermal expulsion, thus exhibiting a completely different cleaning behaviour. By identifying the process windows, this study demonstrates that how different contaminants can be removed without causing visible damage to the nickel coating. Overall, the findings highlight the fundamental role of laser surface preparation in improving the robustness of battery manufacturing for electric vehicles.