Print

Mail

wiki links

GM, Daimler look to lithium ion for hybrids

Daimler chief executive officer Dieter Zetsche appears on screen as he poses with a Mercedes-Benz SL 63 AMG at the press day of the 78th International Motor Show Geneva in Switzerland on Tuesday. PHOTO: EPA

General Motors Corp (GM) and Daimler AG unveiled plans on Tuesday for lithium-ion hybrids as automakers push to overcome difficulties with a technology that promises to push hybrid autos to the next level of performance.

Daimler AG will be the first to get to market, announcing plans to introduce a hybrid version of its Mercedes-Benz flagship S-class luxury sedan using a gasoline engine and a lithium-ion power source next year.

The new S-class is what is called a "mild" hybrid, meaning the electric motor aids combustion but does not itself drive the car, instead boosting the main engine. The new models will achieve a carbon dioxide emissions level of 190 grams per kilometer, higher than many small cars with efficient engines but which Daimler strategist Johannes Reifenrath said would make it the most efficient luxury car in the world.

To date, the least-emitting car in Mercedes' fleet is the diesel S-class with 230g/km.

The Mercedes example demonstrates the application of the technology at the luxury end of the market and is driven in part by tougher regulations taking effect in Europe in 2012 that would require automakers to reduce average emissions in their fleet to 130g/km.

"Change has to start now. Automakers can't wait until 2012," Reifenrath said.

General Motors said it expects to bring its first lithium-ion battery powered hybrid engine system to market in North America sometime in 2010. No product has been announced yet, but officials said the technology had potential across a broad range of product models.

GM showcased the technology in a Saab concept car, boasting carbon emissions of 117g/km on gas and 105g/km on ethanol. Unlike GM's other hybrid project -- the Volt, which has a large battery that can move the car by itself -- the new concept uses a smaller battery about the size of a case of soft drinks to assist the main internal-combustion motor.

The dual announcements indicated increased confidence in the technology, already widely used in consumer electronics. But adapting to meet demanding auto requirements has been an obstacle as has concerns about costs and overheating.

"I think there's a trend there. I think it is good news that Mercedes and GM are coming out at the same time," GM spokesman Scott Fosgard said.

GM is working with Hitachi, which has used a lithium-ion battery in an electric car, to develop its technology. GM's chief hybrid engineer, Stephen Poulos, said that the Hitachi battery design would give the GM application a degree of stability because it was easy to regulate the flow of energy -- but that tests were still being done to ensure stability to prevent overheating and the potential for fires.

"There are a lot of controls to make sure that doesn't happen," he said. "It is a more forgiving application of the lithium ion than most applications out there."

Because they are smaller yet more powerful than the nickel metal hydride batteries used in first-generation hybrid cars, like Toyota Motor Corp's Prius, lithium-ion technology holds the potential to be used across a wider range of models -- as Mercedes' launch of the technology in its powerful S class indicates.

GM chief executive officer Rick Wagoner said the company expected the technology to improve fuel economy by 20 percent. But he said to have a real impact, the technology must drive high volumes.

"The view is that the technology has the opportunity to get a much better range on a small battery and this has a chance to break through in a big way," Wagoner said.

GM said it expects hybrid sales volumes to exceed 100,000 vehicles per year. The system would build on GM's current hybrids, reducing engineering costs and the cost to consumers, the company said.

The battery system would be mated to a wide range of GM engines, including turbocharged gasoline, diesel and bio-fuel power plants. GM said in a statement that the new hybrid system would save fuel by turning the engine off at idle and cutting off fuel during deceleration. It would offer brief electric-only power, the company said in a statement.
This story has been viewed 857 times.