Kevin Bennion, senior researcher and task leader on the silicon carbide inverter project at the National Renewable Energy Laboratory, operates the water-ethylene glycol test loop.

Heavy-duty EV innovation could prevent overheating while quadrupling power

Heavy-duty trucks account for an estimated 39% of transportation emissions, yet a lot of what the public knows about vehicle electrification is related to passenger vehicles.

Heavy-duty vehicles can be harder to electrify than light-duty passenger vehicles because they require more power and torque to operate. A higher power output produces more heat, which can cause a vehicle’s components to overheat or shut down.

Moline, Illinois-based John Deere is collaborating with the National Renewable Energy Laboratory to develop components for heavy-duty EVs that offer significantly more power than what is currently available while still managing the heat produced.

The innovation

The partners developed a thermal management system that could significantly increase silicon carbide converters’ power density in heavy-duty EVs. 

Power inverters control the electricity flow between DC and AC systems, and high-efficiency converters are considered essential for lower-emissions vehicles. EV inverters often manage heat by running a fluid coolant over components’ surfaces to cool them quickly.

NREL developed an advanced system that uses water-ethylene glycol coolant and a perpendicular jet flow, which increases heat transfer away from the inverter. The design could bump up power density 378% over silicon-only inverters, according to studies. It also uses the existing diesel engine cooling system equipment instead of the typical heavy-duty inverter design that requires a separate coolant system.

“The SiC inverter technology stands out among all competing technologies in terms of energy efficiency, fuel economy, performance, and system integration,” Kevin Bennion, NREL senior researcher, said in a news release. The key to the thermal management innovation is to “improve the heat transfer coefficient, which allows this system to cool itself efficiently and continuously during operation with the engine coolant.”

John Deere’s engineering team has helped with demonstrating the technology. 

What’s next

The new inverter is smaller and lighter than existing systems. The lighter weight and improved efficiency are expected to help heavy-duty equipment owners improve fuel efficiency and lower operating costs.

The technology’s initial cost is currently higher than competing technologies. Uptake is expected to initially occur in industries such as heavy-duty machinery, aviation, and the military. It could spread to other sectors as costs come down.