Copper Industry Loves EVs - They'll Use 2-3 Times As Much for Wiring, Motors

Copper Industry Loves EVs - They'll Use 2-3 Times As Much for Wiring, Motors

By John O'Dell March 9, 2010

We know the batteries are a huge cost item for electric-drive vehicles, and the hardware and software for the power electronics, system cooling and other technology-related differences also conspire to make EVs more costly than their conventional internal combustion counterparts.

It isn't just the big, high-tech suff that costs more, as shown in a recent report from the Copper Development Assn.

The trade group happily points out that while the average car built in North America uses 50-55 pounds of copper, mostly for wiring, the typical high-end electric-drive vehicle - a battery-electric like the upcoming Nissan Leaf or an extended-range plug-in hybrid such as the Chevrolet Volt - will use 150 to 180 pounds.

At today's price of about $3.40 a pound for the bulk metal, that's a difference of $340 to $442 per car for the raw material - before the copper is processed.

Standard hybrids, such as the Toyota Prius or gas-electric Ford Fusion also use considerably more copper than do conventional cars.

Much of it is in the electric motors, which use hundreds of feet of tightly wound copper wire on the rotors, and the high-voltage cables that carry power form the batteries to the power inverters and from the inverters - which change the power from direct to alternating current - to the electric motors.

The Chevy Volt system uses two electric motors and two inverters and the copper cables from inverter to motor each weight close to 40 pounds.

Though much heavier - and more expensive - than aluminum, copper is preferred for electric vehicles because it is more efficient in transferring heat, enabling motors and inverters to run at lower temperatures.

It also is more conductive than aluminum, meaning the cables needed to carry high voltage current, although heavy, can be less bulky than if made of lighter aluminum - an important factor in autos, where space not used for cargo and passengers is at a premium.

John O'Dell:  is an AutoObserver Senior Editor. Follow @AutoObserver on Twitter.