Enhancing Reliability of High-Performance Power Module With Advanced Silicone Encapsulation

As a critical component of power modules, silicone gel (SG) insulating encapsulants play a vital role in determining the operational reliability and stability through their long-term electrothermal performance. In this study, we propose a novel encapsulation scheme for power modules that combines high electrical insulation with excellent thermal conductivity. We investigated its failure mechanisms under multi-stress aging conditions and systematically examined the evolution of its electrical properties. Additionally, the electric field distribution was analyzed through numerical simulations. Key results indicate that after thermal-oxidative aging, AO@NDA/SG achieves a breakdown strength of 20.54 kV, representing a 36.4% improvement over conventional SG, while the corresponding power module exhibits a partial discharge inception voltage (PDIV) of 7.73 kV, 26% higher than that of SG-encapsulated modules (6.13 kV). Simulation results reveal that the maximum electric field intensity in the AO@NDA/SG module is reduced by 26.4% compared to the SG module, indicating significantly enhanced field grading capability. Moreover, the AO@NDA/SG composite demonstrates superior thermal performance. This study provides valuable insights for the development of advanced insulating encapsulation solutions for power electronics packaging applications.