FRANKFURT, Germany -- You probably won't see Volkswagen and Better Place forming an alliance anytime soon.

Battery swapping in electric cars is expensive and impractical on a number of levels, said Ulrich Hackenberg, a member of the VW board and the executive who oversees technical development, during a roundtable with reporters at the International Auto Show taking place this week in Frankfurt. Car manufacturers, for one, don't like the idea because it would homogenize their cars and service stations would have to stock a huge variety of expensive batteries.

"The battery defines the architecture of the car. It only makes sense if you have the same type of battery for every car," he said. "I can't imagine all of the OEMs are building their cars around this type of battery.

"We won't do that," he said.

It is also unclear whether consumers would accept it. "In the German market, the customer wants to own the car and he will want to own the battery. He does not want a battery that is old or losing performance," Hackenberg added.

The only advantage of battery swaps, he said, is that the customer doesn't have to buy the battery, thus lowering the purchase price.

Like many other major manufacturers, the Volkswagen Group is embracing hybrids and electrics but with caution. A Toureg hybrid with a nickel metal battery is on the way next year and Audi will release a lithium-ion hybrid after that. In 2012, Audi will then release an all-electric sports car currently called the e-tron while Volkswagen will in 2013 release a commuter car now called the E-Up!

"We will be in the market with this car [the E-Up!] in 2013," Hackenberg said. "The reason we are looking at EVs is the American market. EVs will be necessary to sell cars in the USA."

Still, executives quickly add that the company will scrutinize customer acceptance, the cost of components and other factors before committing to releasing large volumes of electrics. More aggressive government policies on low-emission cars, meanwhile, could prompt the company to push electrics more, said Stefan Jacoby, CEO of Volkswagen America: Regulations are one of the motivating factors, he said. Volkswagen's current estimate is that only 1.5 percent to 2 percent of cars will be all-electrics in 2020. Tesla, Renault and other electric proponents put that figure at 10 percent and higher.

"We want to make sure we have problem free mobility," Hackenberg said. "We don't know how the customer will use such a car."

One thing that may help bring the price down is modularity: Designers will try to exploit the same basic architecture and common components for hybrids, plug-in hybrids and all-electrics.

Other subjects he touched upon:

• Americans and Europeans truly are different. A version of the E-Up! in Europe might only go 130 kilometers on a charge. "For California that may not be enough. It is a very large area" he said. As a result, the U.S. version will likely make it 200 kilometers on a charge and the car will be larger. (It comes with an electric scooter too for distant parking.)

• Car designs also vary with continents. European trunks are thinner. "In the USA it is absolutely necessary to carry two golf bags in a transverse position," he said. "In Europe this is not so important but in the U.S. it is a necessity."

• Sales aren't great but they are rebounding slowly. Total auto sales in the U.S. will come to about 10 million cars this year and 10.5 million in 2010, said Jacoby.

• Mileage will keep going up. At the show, Volkswagen showed off the high-concept L1, a two-seater diesel hybrid that looks like a bobsled on wheels. It gets 170 miles per gallon.

• "It defines some peak technologies for cars," Hackenberg said.