Efficiency enhancement of Li-ion battery electrode structuring by pulse burst processing: results of an automated study

Structuring electrodes of lithium-ion batteries with liquid electrolyte leads to an increase in the performance of the battery cell, as shown in several studies. The effective diffusion of the lithium ions can be significantly increased by introducing microchannels. This leads on the one hand to higher charge and discharge rates, and on the other hand to an increase in the number of charge cycles and thus to a longer lifetime. Even though there are already many publications on the laser structuring of electrodes, the fundamental interaction mechanisms have not yet been fully developed without doubt. Also, the lack of progress productivity is currently preventing industrial application. For this reason, the influence of pulse-bursts on the laser structuring process of the active material of electrodes was investigated within the scope of this work. The influence of the variation of the number of pulse bursts, the repetition rate as well as the peak fluence on the ablation rate and the ablation efficiency was investigated. The results were evaluated by an automated analysis procedure to allow a systematic and statistical assessment of 110 induced features per parameter set in a time-saving manner. It was shown that the efficiency of the individual pulses could be increased by up to 75% when machining NMC. Due to the pulse bursts, a five times greater increase in the ablation rate could be achieved on the anode side. In addition, cross-sections of the introduced pores were examined by scanning electron microscopy combined with EDS analysis to identify a possible thermal influence of the laser material processing.