Development of High Voltage Multilayer Ceramic Capacitor

MLCC serves as a filter for reducing the noise of electric current. BaTiO₃ (BT) is currently used as a dielectric material for high capacitance MLCCs. As power and charging speed of the EVs improve, higher voltages need to be selected. BT has material limitation in that the dielectric constant decreases with increasing voltage. Therefore, sacrifices have to be made in capacitance by decreasing permittivity or antiferroelectric materials need to be utilized. In this study, PLZT-based MLCC with higher dielectric constant than BT in 200–400 V was developed. The contents of Pb, La, Zr, and Ti were optimized, and Ni electrode was replaced with Cu to reduce cost. To solve possible Cu oxidation and PbO reduction, oxygen partial pressure was optimized.