| 초록 |
The propulsion system in most Electric Drive Vehicles are equipped an electronic device called a power inverter which converts battery DC voltage into AC power for the motor. The inverter must be decoupled from the DC source, so a large DC-link capacitor is placed between the battery and the inverter. The DC-link capacitors in these inverters negatively affect the inverters size, weight and assembly cost. To reduce the design/cost impact of the DC-link capacitors, novel dielectric materials with low loss, high dielectric constant (κ) are being developed. To design a proper dielectric material for the energy storage application, three requirements have to be considered at the same time: large saturated polarization, small remnant polarization, and high electrical breakdown strength. A wide variety of polymer passed composites design with ceramic nanofillers have been tried to achieve the enhanced dielectric polarization while maintaining the strongly insulating nature of the polymers. In this study, aluminosilicate nanosheets exfoliated from the natural mineral (Mica) were investigated as fillers for the high energy dielectric composites. 2-D nanosheets are promising fillers for preparing flexible polymer-based nanodielectric materials because of their unique two-dimensional structure and excellent electrical, thermal and mechanical properties. However effective dispersion of the nanofillers and filler/matrix nanoscale interfacial adhesion are still challenging to realize the enhanced dielectric performances of the dielectric nanocomposites. Polymer assisted exfoliation process by PVP molecule was very effective to achieve nanosheets in lateral size of 5-10 um and thickness of about 1-2 nm. The FTIR and Raman spectroscopy results indicated presence of PVP molecules on the both sides of the exfoliated muscovite nanosheets, where the hydroxyl groups formed on the aluminosilicate surfaces in aqueous solutions were tightly bonded with carbonyl groups of the pyrrolidone moiety. A strong interfacial adhesion with the matrix is responsible for the enhancement of dielectric properties. |
