By Bob Weed, Copper Development Association Vice President, OEM
The Copper Development Association (CDA) and its member companies are long-time supporters of hybrid and electric vehicles. The CDA built and tested three vehicles in the 1970s to demonstrate the capabilities of electric vehicles and to help improve supporting technologies. Bob Weed, Copper Development Association vice president of original equipment manufacturing, says the copper industry is still committed to developing new technologies for electric transportation.
Recently, the CDA provided technical assistance to Cobasys LLC for their NiMH batteries. The project involved helping to determine the optimum copper alloys for use in batteries and then partnering with Edison Welding Institute (EWI) to develop effective joining technologies that could accommodate high-volume, high-speed production.
Copper companies have developed new, high performance alloys for connectors and new magnet wire profiles that result in more efficient motor windings. One of the more exciting developments is the cast copper motor rotor. It’s always been known that a copper rotor is more efficient than a traditional aluminum rotor, because copper is a better conductor of electricity and has lower resistance. Therefore, motors with copper rotors can be smaller and run cooler. The result is an induction motor with the highest power density possible today.
The first transportation application for this technology was the U.S. Army severe-duty trucks. Four 140-hp AC induction motors are used to power the truck, one on each of four axles. The 520-V motors are powered by a 400-hp diesel engine, making a hybrid drive system that can move the 35,000-pound vehicles and run a 335-KW generator to operate field hospitals, command centers or airstrips. Called ProPulse® by Oshkosh Truck Corp., the innovative hybrid electric drive system is said to decrease emissions and increase fuel economy by as much as 40%. Aside from several configurations for the military’s 8×8 HEMTT-A3 (Heavy Expanded Mobility Tactical Truck) series, the drive system is also configured for commercial use with refuse vehicles. Oshkosh says the new drives will lower life-cycle costs as well as lower interior and exterior noise profiles.
I’m also introducing this technology to manufacturers of passenger cars and light trucks. These vehicles require motors that are smaller, more efficient and run cooler. Plus motors using cast copper rotors don’t rely on rare earth elements. Rare earth elements, used in permanent magnet motors, are expensive and have to be imported to North America.
In addition to propulsion systems, a number of very talented people are working on charging systems and infrastructure for hybrid and pure electric vehicles. The Center for Automotive Research (CAR) organized a conference last fall that brought together electric utilities, auto companies, and charger manufacturers. Some of these presentations are still available on their website and hopefully there will be more conferences like this in the near future.
The CDA and the copper industry have been involved in electric propulsion for decades, but some of the most exciting advancements will take place over the next few years. And I’m looking forward to being involved in them.