New Aspects in the Understanding of High Voltage Aluminium Electrolytic Capacitors

High voltage (HV) Aluminium electrolytic capacitors with working voltages over 400 V are the backbone of industrial and automotive electronics. Recent developments in the field of fundamental understanding of the electrical breakdown of the anodic oxide of high voltage Aluminium electrolytic capacitors are presented. The adsorption of long chain organic molecules increases the breakdown strength of Aluminium electrolytic capacitors, because the relation between the injection current and the breakdown voltage, on the one side, and the electrical parameters of the electrolyte (either resistivity or conductivity), on the other side, originates from the Freundlich adsorption isotherm which relates the surface number density of the reducing agents with their volume number density. Experimental and literature data are discussed.