Low-stress silicone encapsulant for reliable power conversion devices

The emergence of distributed energy production and vehicle electrification has created the need for power conversion devices that remain highly reliable even when exposed to outdoor climatic conditions for decades. We describe a new encapsulant that contributes to reaching this kind of reliability. It is a tacky and soft silicone material that applies minimal stress on electronic components during thermal cycling and shows thermal conductivity to evacuate heat, while enabling fast assembly thanks to low viscosity and high cure speed. Material properties are described and compared to those of conventional power device encapsulants. Device testing is also reported, including stress measurement in encapsulated devices.