Numerical and experimental study on coating uniformity control in simultaneous double-sided slot coating with a novel contacted slot die

•Simultaneous double-sided slot coating efficiency is twice that of single-sided one.•Contacted slot die boosts coating evenness in simultaneous double-sided slot coating.•Contacted slot die suppresses the gap fluctuation caused by substrate vibration.•Coating uniformity decreases as substrate vibration frequency increases. Simultaneous double-sided slot coating (SDSSC) has been developed to improve the efficiency of lithium-ion battery electrode production, but the coating uniformity is limited owing to the gap fluctuation caused by substrate vibration during coating the second side. Here we investigated the SDSSC with a novel contacted slot die and discussed its coating uniformity. A validated numerical model was established to describe the gap fluctuation and analyze the frequency response of coating uniformity to it. The numerical results indicate the contacted slot die can suppress the gap fluctuation to two orders of magnitude smaller than the non-contact slot die. There is a range of substrate vibration frequencies for guaranteeing the coating uniformity because it decreases with increasing frequency. In experiments with different coating thicknesses and speeds, the coating uniformities all exceeded 95% and improved upon increasing these parameters. The contacted slot die is effective at controlling coating uniformity in SDSSC.