Mercedes Rejects Electric Car Battery Swapping

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.

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.

More Hybrid News...

  • moishe k

    keep it simple

    small battery with range extender engine

  • Ross Nicholson

    Small battery, recharged from mains while moving over the road. Tesla’s idea. (Moving electricity by shipping heavy batteries is less intelligent that moving electricity through wires and transferring power wirelessly over the short distance from roadway to vehicle.)

  • Steve Lyons

    How many of us really want to be repeatedly subjected to the EMI fields needed to propel a vehicle for any distance? There are already concerns, although debatable, regarding exposure to low power cell phones. I would raise the same concerns over alternating magnetic fields used to power/charge a moving vehicle with occupants. Not to mention the inductive heating effects of any metals moving through those fields. Do we really need to live life in a long wave oven?

  • Tony

    This is something I’ve been thinking about for a while.

    Ideally I’d like to see a modular system in which, instead of a swappable battery, a vehicle has a fixed battery of some capacity with a gap or slot designed to accept some sort of modular range extender. The type or range extender would not be important, as only the electrical properties would matter. IE you could install a small gasoline engine, or extra batteries, or anything else meeting the electrical specs into this slot and the car wouldn’t know the difference. As an immediate benefit, say your daily round-trip commute is more than the 40 or so miles you can get with the built-in batteries, but not by so much as to warrant the gasoline engine, you could install an auxiliary battery pack that would get you just what you need to get back and forth to work. If you’re taking a cross country road trip, you pull out the battery pack and install the gasoline engine to extend your range indefinitely.

    But the key advantage here, given the rapid advances in technology that are taking place, is that when a newer and more efficient power storage or generation mechanism becomes commercially viable, you don’t need to buy a new vehicle to make use of it. Whether it’s a lighter battery technology with triple the energy density, or cheap and plentiful bio-diesel harvested from GM algae, or “Mr. Fusion” from the film “Back to the Future”, any such technology could become immediately available to any owner of a car utilizing such a modular system. Manufacturers of such systems would have an immediate marketplace in the form of what we in the software industry call the “installed user base”. You don’t need to get an exclusive deal with an automaker and wait until they design, build, and start selling cars using your new ultracapacitor before you start turning a profit. You build it into a module, put it on the market, and start taking orders directly from consumers right away.

    As a bonus, you’d mitigate going forward the problem posed by the fact that it takes decades for any new transportation technology to fully penetrate the market. IE if you produce the “perfect car” tomorrow there would still be the problem that there are hundreds of millions of standard ICE vehicles on the roads that will not be replaced overnight. Obviously we’re not going to build the perfect car tomorrow, or next year. But we could very well be building a substantially better car in the next 20 years, and if there are already 10 million modular vehicles on the road by then, you’ll effectively have a 15 year head start on deploying the technology.

  • Paul Rivers

    How many of us want to be exposed to gasoline, a known carcinogen (see the little stickers at the gas pump) every time we fill up the tank? How many of us want to be exposed to auto exhaust – a mix of chemicals that will actually kill you if you breathed in nothing but auto exhaust – every day we go to work? And do you know what happens if your exhaust system gets a hole in it in the wrong place below the driver and starts coming in the cabin? You can actually die. Right there, if you don’t notice and don’t have any external ventilation.

    I’m also not sure that electric cars even give off EMI. It’s my understanding that only alternating current does that, and despite what your post implies, electric cars don’t use “alternating magnetic fields”, they use direct current. Alternating current is only used to transmit power over long distances – completely unnecessary even in the largest of cars.

    I also don’t think that you’ve realized that your *entire home* is wired with 120v (or 240v I believe, if you live in Europe) wiring that goes through every wall in your home. It’s surrounding you there – it’s in every wall in your bedroom, and every wall in your house. And that IS alternating current. If you sleep 8 hours a day, you’re spending 8 hours a day there – that’s where you should start with your concern.

    The other thing is that EMI can be shielded, and this is the only worthwhile safety concern about EMI in an electric car – IF, and it’s a very open ended IF, IF an electric car gives off any amount of EMI, should it be mandated that it be shielded?

  • Hilary Shaw

    Thomas Weber’s argument is apparently based on safety yet he advises we should wait, presumably to seek a perfect solution before innovating, and says gasoline and diesel will dominate for another ten to 20 years. A wee flaw in the logic here, perhaps? If gasoline and diesel powered cars dominate for another decade or two, car batteries will surely be among the least of our health and safety concerns!

  • Dom

    I really like Tony’s idea of a modular upgradeable car (reminds me of computers…)

    Unfortunately the car makers probably prefer we buy a whole new car every three years… and they’ve spent a lot of time and effort to train us to do that…

  • Tony

    Regarding EMI, the author of the post to which you were responding was himself writing in response to a specific proposal to have electrically driven vehicles powered or charged by power transmitting antennae embedded beneath the road. In other words, someone was talking about intentionally having the roadway generate EMI that appropriately equipped automobiles could then receive and turn into usable power. So yes, the EMI safety issue is a real one.

    I think this single misunderstanding mitigates the remainder of your post. For example, in order to effectively power an electrically driven vehicle, the EMI generated by such a system would necessarily have to be far more intense than anything that’s going to come from your house wiring.

    And as for shielding, obviously shielding the source of the radiation would defeat the entire purpose. You could probably shield vehicles equipped to receive such power transmissions from the radiation and just place the receiving antenna outside the shielding, but what of the installed base of traditional vehicles?

  • Paul Rivers

    “Regarding EMI, the author of the post to which you were responding was himself writing in response to a specific proposal to have electrically driven vehicles powered or charged by power transmitting antennae embedded beneath the road. In other words, someone was talking about intentionally having the roadway generate EMI that appropriately equipped automobiles could then receive and turn into usable power. So yes, the EMI safety issue is a real one.”

    Well I feel stupid – I misread his post slightly, I thought he was talking about having the battery in the car, and he/she’s talking about the electricity coming from the roadway – completely different. My apologies.

  • Solomon

    mass transist . bicycle and electric trains. buses, trucks,cars lorry fitted with pantographs just like regualar trains. Mobile highways, that is , electric trains capable of transporting over 500 cars at once.

  • Tony

    “Well I feel stupid – I misread his post slightly, I thought he was talking about having the battery in the car, and he/she’s talking about the electricity coming from the roadway – completely different. My apologies.”

    No worries, you can’t be the only one who made that mistake. Had you not said anything, it stands to reason that someone else, having had the same misunderstanding, would have walked away thinking that EVs are an EMI hazard.

  • RKRB

    The author has helped us understand the issues. Paul Rivers, and Mercedes, also make excellent points.

    Yes, w,e already expose ourselves to substantial risks from existing electrical and liquid fuel sources (including intangible and unquantifiable risks of “wars to protect oil supplies,” etc.). The relative risks, uncertainties, and probabilities involved in things like EMI, shielding, carcinogenicity of gasoline vapors, etc., unfortunately, are fiendishly difficult to quantify and to understand, and even then, unintended random events can distort things further. To make things even worse, we often leave these issues in the hands of politicians and others who are probably the least qualified and least ethical people to manage them. We could, as an option, establish some kind of “quantocracy,” where mathematicians and quantitative experts could come up with reasonable solutions to manage risk. After all, the quants have used sophisticated mathematical computations to do a most excellent and predictable job of managing risk in the mortgage and stock markets, uh, right?

    This is a complex system and only one thing can be certain — a simple, one-size-fits-all explanation or solution will predictably be probably wrong. Minimizing risk and maximizing benefits are excellent solutions, but they inherently involve probability. This is as an unavoidable condition of just being alive.

  • simon@syd

    Could wrieless energy transfer ever replace the pantograph? I suppose that would make a real EMI though.

  • Tony

    While wireless power transmission has it’s challenges, I’d submit that to be useful, you don’t have to wirelessly transmit sufficient power to completely power the vehicle. Anything that would extend the electric range would have some value. I envision a vehicle with a pretty hefty battery, maybe a modular gasoline engine that could be removed and replaced with additional batteries, or with nothing, and a multi-source energy harvesting system. Maybe the batteries in a typical near term car could get you 100 miles, and the addition of solar cells on the roof and some sort of low-power wireless energy transmission can expand that by 10 miles. That could be enough to get you to the next roadside recharging station, or to reduce your gasoline usage by 10 miles.

    Also, the effectiveness could increase as battery capacity increases. If you can harvest 10 miles worth of energy while driving 100 miles, then if you get a new battery that can take you 200 miles, you’d be able to harvest 20 miles worth of energy per charge.

    Some other possibilities: As PV efficiency continues to increase, maybe it eventually becomes more efficient to use an optical coupling to beam power from the road to the bottom of the car than some kind of inductive technique. PV cells are usually effective at a limited range of wavelengths. So a cell that is 5% efficient over the entire solar spectrum of light might be 30% efficient at some narrow range. Imagine vehicles with PV cells mounted on the undercarriage, and LEDs emitting at the optimum wavelength for those PVs embedded in the road surface, with some short range wireless signaling technology telling the road when to turn each LED segment on and off as a vehicle passes over it. I bet you could eventually realize some pretty decent power transfer, with no EMI, and reasonable efficiency.

  • HC Reader

    Hardly practical or achievable, today or in 15+ years.

  • Simsen

    Doesn’t take you off oil though….

  • Carl Danner

    Did you know that during a lightning storm one of the safest places you can be is inside a car. The reason is that the metal around the passenger compartment shields you from EMI. The electricity tends to flow in the metal rather than in you because the metal is a much better conductor of electricity.

    The main purpose of battery-swapping should be to allow EV owners the option to install the type of battery that meets their needs best. Check out my site.


  • Sandru Mircea

    I think that Mercedes hybrid and electric cars will be very popular in few years. I love every Mercedes model and i think I will enjoy also an electric Mercedes. I write about similar cars on

  • Steve Bucks

    The point about the lack of standardization of batteries is a bit dubious. You could have no doubt made this point at some time in the past about regular filling stations – how can we have filling stations across the country when the openings to tanks on cars are all different sizes?

    They just negotiated a standard and the problem was solved – just as they would with electric batteries. It hasn’t happened yet, but that’s simply because there’s been no need to do it yet.

  • Lisza Bailey

    nice this one really nice article right now and also i just wanna know if this vehicle right here have the a/c relay and having this old car