Study on slow polarization phenomenon in high energy density capacitors

When the Metallized polypropylene film capacitors (MPPFCs) are used under a high electric field, an obvious voltage decay phenomena will occur. And the voltage decay may finally decrease the practical output energy of the capacitor. This kind of phenomena is not only due to the influence of the dielectric conduction, but also the slow polarization of the dielectric. Due to defects or amorphous regions in the dielectric material, there is slow polarization in MPPFC when it is applied under high electric field. The completion of slow polarization may take several seconds or several minutes or even longer. If MPPFC is disconnected from the power source without fully charged (the slow polarization process is unfinished), the voltage decay will occur in a relatively significant value for the slow polarization and dielectric conduction.