Thermal Management in the Silicon Carbide Revolution, Discussed by IDTechEx
BOSTON, Oct. 13, 2021 /PRNewswire/ -- For electric vehicles (EVs), efficiency is the name of the game. There are many avenues to improving efficiency, especially within the drivetrain with one of the key areas being power electronics. Of these components, the main inverter is the highest power and gives the best opportunity for efficiency improvements. The main inverter is responsible for converting the DC output of the battery into an AC input for the electric motor. In the past few years, we have started to see wide bandgap semiconductors such as silicon carbide (SiC) adopted in EV inverters to replace the typical silicon insulated-gate bipolar transistors (Si IGBTs). The use of SiC enables higher density power modules that can operate at higher temperatures, leading to new thermal management and material opportunities for EV power electronics.
The SiC Transition
Despite the increased cost of SiC metal-oxide-semiconductor field-effect transistors (MOSFETs), their penetration into the EV market has been substantial. According to IDTechEx research, in 2020, SiC MOSFET inverters made up nearly 30% of the EV market globally. Tesla started the trend in 2018, with others like BYD have vehicles on the road. Giants like Stellantis and Hyundai are including SiC power electronics in incoming models to help enable their high voltage (800 V) platforms. IDTechEx's new report on "Power Electronics for Electric Vehicles 2022-2032" considers the transition to SiC in addition to deep analysis of power electronics for the EV market with examples from EV models, the supply chain, and package materials and innovations.
Thermal Management Challenges
Power electronics in EVs present interesting thermal management challenges and the adoption of SiC changes several aspects of the module and package design along with material selection. In a traditional power electronics package, several potential failure points occur with thermal cycling. As the package heats up and cools down, the mismatch in thermal expansion between materials causes degradation of various connections, these include the wire bonds, die-attach, and substrate-attach. In SiC packages, power density and operating temperature can be increased significantly, meaning that certain traditional options are no longer suitable.