The capacitance loss mechanism of metallized film capacitor under pulsed discharge condition

The metalized capacitor has high energy storage density for its self-healing characteristic and is often used in pulsed power applications. The pulse life is defined as the number of charge/discharge cycles before 5% decrease in capacitance. In order to reduce the capacitance loss in the active electrode area (AEA), segmented electrodes are designed to decrease the clearing energy. In this electrode pattern, a large capacitance loss is observed along the segmented electrode edge (SEE). The loss along the SEE is caused by two reasons: electrode recession caused by electrochemical corrosion and self-healing induced by the combined effect of partial discharge and electric field distortion. According to teardown observation, there is an unexpected capacitance loss competition in the AEA and along the SEE under various voltages. Based on the analysis of the capacitance loss mechanism, three kinds of metalized electrode patterns are designed and tested. The result indicates that a proper electrode pattern helps to increase the pulse life of capacitor.