Abstract: In a process for the operation of copper electrolysis cells including a plurality of anode and cathode plates arranged vertically and parallel to each other, a longitudinal electrolyte inflow and an electrolyte outflow, the electrolyte is injected via the electrolyte inflow horizontally and parallel to the electrodes in each electrode gap always at the height of the lower third of the electrodes at a speed of from 0.3 to 1.0 m/s, with the cathode plates being arranged stationarily relative to the inflow direction. As a result, an optimized flow guidance of the electrolyte with regard to the electrodes is achieved, resulting in an increase in the limiting current density.