Johnson Controls develops 48-volt lithium ion battery for electric vehicles

Johnson Controls Inc. is developing a 48-volt lithium ion battery for European automakers.

The higher voltage is needed to handle a growing number of electrical systems that save fuel but need more volts, such as stop-start, electric power steering, regenerative brakes and other energy-efficient electrical systems.

Alex Molinaroli, president of JCI’s battery division, says an unnamed European automaker will introduce the higher voltage system as early as 2015. The vehicle to be produced will have two batteries: a conventional 12-volt lead-acid starter battery and a lithium ion battery for the high-voltage hardware.

Molinaroli, speaking at the Detroit auto show, says his company has a development contract to produce the batteries. “It will happen, and it will happen first in Europe,” he said after a press conference here today at the show.

Such systems are not cheap. Automakers will have to redesign a vehicle’s alternator and starter, and such a system might cost the automaker $1,200 or so. A motorist might expect to recoup those costs in three years or so from higher fuel economy, Molinaroli said.

General Motors adopted a two-battery system — with a lead-acid battery and a lithium ion unit — for its eAssist mild hybrid technology, which is in such cars as the Buick LaCrosse.

BMW, Audi and Mercedes-Benz also have used dual lead-acid batteries to accommodate their stop-start systems, Molinaroli said.

But dual-battery electrical systems should be considered an interim technology, Molinaroli cautioned. Eventually, automakers will want to consolidate to just one battery.