Reliability Testing of Liquid Metal Embedded Elastomers for Power Modules

Abstract:
The connection between high-powered SiC modules and cooling systems for electric vehicles require reliable low-resistance thermal interface materials (TIMs). Recent advances have shown liquid metal embedded elastomers (LMEEs) as viable alternatives to solders and sintered silver for these interfaces. Here, we investigate the long-term reliability of LMEEs through accelerated testing following AQG324 standard test conditions, including high temperature, high humidity, and thermal shock testing. Additionally, we present experiments on other factors affecting adhesion, including chemical compatibility, sensitivity to surface contamination, and the effects of surface oxidation. Finally, we identify assembly process bounds and probe for additional failure mechanisms, pointing to promising areas for further R&D efforts. Overall, this work points to the benefit of encapsulating liquid metal (LM) in polymers to achieve the low resistance interfaces promised by LM while attaining automotive-grade reliability.