Pressure build-up in aluminium electrolytic capacitors under stressed voltage conditions

The internal gas evolution in aluminium miniature electrolytic capacitors exposed to stressed current and temperature conditions has been measured. The gas evolution is controlled by two competitive processes: hydrogen generation at the cathode and reduction of the depolarizers added to the electrolyte. The kinetics and efficiency of these reactions have been determined from measurements of the gas evolution for different temperatures and different currents through the capacitors.