GM plans to announce electric motor plant for Volt

General Motors plans to announce in Washington later this month that it will build or operate a U.S. factory to make electric motors to power electrified autos.

GM last week built the first lithium-ion battery pack for its Chevrolet Volt electric sedan at a newly opened GM factory in Brownstown Township, Mich. Volt is to go into production in December. After batteries, electric motors are "the second leg of the stool," Tom Stephens, GM vice chairman in charge of global product operations, said in an interview with USA TODAY at the Detroit auto show Tuesday.

The "third leg" supporting electric-car production will be the electronics that control the way the batteries interact with the motors, Stephens said. He did not say if GM also will build those electronic systems, but implied that it would: "Electric motors, batteries, power-control electronics -- you need core expertise in those."

He also noted that a company needs such expertise to carefully shop for a supplier for those components.

Stephens said the motor factory will be in the USA. But he declined to say more about the factory until the announcement in Washington later this month.