Space Charge Behavior in Epoxy-Based Dielectrics: Progress and Perspective

Epoxy-based dielectrics are extensively used in grid-connected energy systems and modern microelectronics as electrical insulation, adhesive, and packaging components. However, space charge accumulation in epoxy-based dielectrics is a foremost factor threatening device stability and lifespan, especially under conditions of high voltage direct current and high temperatures during long-term operation, and thus are investigated systematically. This article reviews the state-of-the-art progress in understanding and regulating the space charge behavior of epoxy-based dielectric materials. The development of space charge measurement techniques is first introduced. Then, experimental observations of macroscopic space charge characteristics in epoxy dielectrics under different conditions, along with the advancement of nanofiller-doping strategies for improving space charge suppression capabilities, are discussed and emphasized. Afterward, simulation progress based on the bipolar charge transport models and quantum chemistry calculations are summarized to provide some insight from a microscopic perspective. It is concluded by providing a brief summary and highlighting future research opportunities in inhibiting space charge accumulation of epoxy-based dielectrics for practical applications in power equipment and electronic devices.