Mercedes Rejects Electric Car Battery Swapping

By · March 09, 2009

Shai Agassi, the founder of Better Place, has convinced heads of state, governors, wealthy investors, and powerful chief executives that a network of electric car battery recharging and swapping stations will help solve the world’s energy problems. But a growing number of skeptics are questioning the feasibility of the plan—especially the concept of swapping discharged batteries with fresh ones.

Mercedes LE 306 Van with Battery Swapping

In the early 1970s, Mercedes experimented with battery swapping on electric vehicles, but abandoned the idea.

The latest skeptic is Thomas Weber, Mercedes chief of research and development. In today’s Ha Aretz, an Israeli newspaper, Weber said that battery-swapping stations for electric cars may, in fact, be dangerous. The Mercedes executive said his company explored a similar plan in the 1970s, and discovered that changing a battery on the road could cause electrocution or fire.

In 1972, Mercedes built an electric bus called the LE 306. The vehicle was limited to 40 miles of range but, according to a company press release, the battery could be replaced using a “push-through horizontal-exchange technology.” The release promised that the process, mostly manual, would take the same time as a fill-up at a gas station. Eighty-nine prototype vehicles were built and the battery swapping system was “extensively tested,” according to the company.

Opposing Views

Weber said that after speaking with Agassi, that he does not share Better Place's vision. The Mercedes executive thinks that carmakers should make electric cars with permanent lithium ion batteries capable of approximately 125 miles in driving range. He said Mercedes is already working to produce such a product.

Better Place, a Silicon Valley start-up with operations in Israel, has been working with Nissan-Renault to create a recharging network for the electric cars that Nissan plans to introduce by 2011. Mass adoption of electric cars has been limited due to limited driving range and a lack of infrastructure for recharging along roadways and other public places.

Better Place believes that highway battery swapping stations would extend the cars' range, and save time for drivers.

More Skeptics

Other industry experts—even strong advocates of electric cars—have questioned battery-swapping. Ed Kjaer, director of electric transportation at Southern California Edison, said, “With battery swap-outs, you’re dealing with 300 pounds of batteries and every one is different.” Kjaer was speaking at Auto FutureTech, an industry conference held in March 2008. He said, “You’ve got liability issues. You have issues around how that battery has been consumed by the previous driver. It’s not there today because the technology is not mature and we don’t have standardization.”

In December 2008, New York Times writer Jim Motavalli also questioned Better Place’s battery swapping approach. “A jumble of battery types from various automakers, without industry-wide standardization, could obviously turn such a plan into a nightmare."

Weber said that Mercedes is looking to develop alternative approach to electric car infrastructure but did not provide details of the plan. He said that for the next 10 to 20 years, almost all cars on the road will still have gasoline- or diesel-powered internal combustion engines—and that achieving a 10 percent market share for electric cars, a target envisioned by Nissan, would require hefty government subsidies.

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