By on August 13, 2010

Not long ago, we explored the possibility of Audi taking out Tesla with its forthcoming brace of e-Tron electric sportscars. What we didn’t realize fully at the time, is how directly VW is going after Tesla. At a recent visit to Volkswagen’s Silicon Valley Electronic Research Lab though, I was shown the slide above, which represents the battery packs for the forthcoming e-Tron and e-Up EVs… and it suddenly hit me that Tesla founder Martin Eberhard was applying Tesla’s multi-cell strategy at Volkswagen, essentially duplicating Tesla’s work with the backing of a major OEM. Now, Eberhard is talking to Autocar, and he says that his Tesla-style multi-cell powerpacks could offer 500 miles of pure electric range within ten years. If he’s right, the other OEMs who are focusing on prismatic Li-ion cells are in for a rude surprise… and Tesla had better start making some progress.

Tesla’s major technological innovation comes down to the idea of massing numerous “18650″ cells in a temperature-controlled battery pack. Though many dismissed the strategy when only Tesla was working on it, Volkswagen is clearly now a believer in the approach, and they’ve got a good case for it. The main arguments for 18650 cells are that they are the most common cell type, new chemistries always debut in the 18650 format, they offer the lowest price and highest energy density, and offer the most flexibility in terms of packaging.

VW also argues that redundancies allow the multi-cell design to offer more reliability and safety… although cost is likely to have been a major issue as well. But perhaps the most important issue is the scaleability and flexibility of the 18650 approach. VW gave us a picture of the kind of progress they’re able to achieve by simply plugging new 18650s into the existing battery pack design:

Clearly progress is being made, but Eberhard’s warning that a mature electric vehicle won’t be ready until 2020 should be well-heeded. It’s not a great sign that Tesla’s founder is warning that we’re ten years away from EV maturity while his former firm is rushing an EV sedan to market in the next two years. But the real challenge of VW’s gamble on Eberhard is to the Nissans, GMs and other firms jumping onto the prismatic Li-ion cell bandwagon. VW has made a bold gamble by betting on a cell strategy that other major OEMs were content to dismiss as Silicon Valley vapor. If an affordable 500-mile EV comes out of it, fortune will have truly favored the bold.

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29 Comments on “VW’s Martin Eberhard Promises 500 Mile Range EVs By 2020...”

  • avatar

    The 18650 is unquestionably the most common lithium ion cell, and it receives the most attention from developers. Its cylindrical form factor will work against it eventually, because a custom prismatic battery won’t have the air gaps that you get in a bank of 18650 cells.

    Use of the 18650 for cars becomes an exercise in manufacturability, because you have to figure out how to connect ~7000 cells reliably, cheaply, safely, and legally (without violating someone else’s patent). A custom prismatic avoids a lot of this trouble, but forces the designer to re-characterize its performance, not to mention spending a lot of money on its development with a single supplier.

    For newbies, “18650″ refers to its diameter (18 mm) and length (65 mm). They are very common in laptop computers, for instance.

  • avatar

    Martin Eberhard has done nothing new and nothing bold. His approach — even if it does not violate Tesla’s battery patent — promises little. Certainly using 18650 cells is not going to increase range, as Eberhard apparently says it will. How could it?

    In fact, I’d be interested in how people are doing with their Tesla Roadsters. Bet you for those that have been on the roads for a couple of years their range is down by half. But no one seems to be saying, one way or another.

    • 0 avatar

      Those Tesla Roadster owners spent a lot of money on their cars. If they were experiencing decreased range after only 2 years, I’m sure they’d be complaining loudly all over the internet.

    • 0 avatar

      You may be right. I’m curious, though. Inquiring minds want to know. And no one is telling.

    • 0 avatar

      It is being discussed… A good place to look might be the owners’ forum.

      Not exactly down to half, it drops a few percent in the first year and tails off more slowly as the car ages.

    • 0 avatar

      “Not exactly down to half, it drops a few percent in the first year and tails off more slowly as the car ages.”

      I don’t think the mileage gauge on the Roadster is going to detect the battery capacity with any accuracy. That would be too hard to do.

    • 0 avatar

      Daanii2, what evidence are you looking for that Tesla battery range isn’t dropping by half? You don’t trust what owners are saying, or our battery meters. How about if I tell you that I’m still taking long trips and still getting the expected range? Let me know what else you need, I’ll see if I can get it.

      I’ve seen Nissan’s lion degradation numbers, and they look very similar to Tesla’s. Nissan’s got an 8-year 100k warranty on it, too. Why would they put that warranty on if they thought it was going to drop by half in two years?

      For that matter, why do you think it will drop in half in two years? I’ve never heard anybody predict that, other than people that have no experience with lion other than in unmanaged consumer electronics devices.

    • 0 avatar

      I’m looking for hard data about the capacity of a Tesla Roadster’s battery pack after one year, and after two years. I’m not surprised that the data is not available. Companies do not like to release that kind of data. But I would like to see it.

      People in the battery industry (and I too have experience in the industry) know about the loss of capacity of lithium ion batteries. It’s because of chemistry. See, for example,

      It’s not that I don’t trust Tesla owners or their battery meters. But I know what those meters measure. They measure state of charge. They do not measure battery capacity.

  • avatar
    John Horner

    I suspect that Tesla roadsters get driven about as much as McClaren F1s do. Weekend toys for occasional fun runs do not put the kind of wear and tear on a vehicle that day in and day out use does.

    • 0 avatar

      With lithium ion batteries, though, the decreased capacity does not come as much from use as from calendar life. Most benchmarks say you lose 1% to 2% per month, starting when the battery is made in the factory.

      Tesla’s battery maintenance system is designed to keep down the heat, which can accelerate the decrease. But I don’t think it works as well as Tesla says it does.

      If Las Vegas took bets on this, my money would say that a two-year-old Tesla Roadster has a 100-mile range. But who knows whether I would win the bet.

    • 0 avatar

      >>I suspect that Tesla roadsters get driven about as much as McClaren F1s do

      I see them at least once a week on I280, or parking in random spots around bay area. Haven’t seen an F1, once.

    • 0 avatar

      @John Horner

      I know a guy that uses a Roadster as his main commute vehicle that does about 100 miles a day in it. He’s put over 25,000 miles on it in the first year with no problems at all.

    • 0 avatar

      Every Tesla owner I know uses it as their primary car. I’ve put on 12k miles in less than a year.

  • avatar

    Ahem .. Tesla-style cells ?
    AC Propulsion, tZero ??

    • 0 avatar
      M 1

      Newsflash: In case savuporo’s comment didn’t make it clear enough, most batteries have been “multi-cell” for about 60 years.

      Given the supposed direction of the industry, I recommend that all car-blog “journalists” take a month off and attend a crash course in basic electronics, perhaps with some lab work specific to electric cars.

  • avatar

    Clearly it’s not “Clearly” at all.

  • avatar
    Robert Schwartz

    Both the Chevy Volt and the Nissan Leaf are claiming 5 mi per KWh. The Leaf runs its 24 KWh battery down to 80% charge providing 19.8 KWh in usable charge, and the Volt uses 50% of its 16 KWh unit.

    The slides shown above refer to 35 and 48 KWh battery packs. Each of which is made of 4608 cells. The difference between them is that the lower capacity one uses ~2100 mAh cells and the larger capacity one uses 2900 mAh cells. In the linked article, Eberhard claims that the next generation of cells will hit 3.4 mAh which would allow a 58 KWh pack. Even with the higher capacity, that is not 500 mi. Either the pack would have to double in size, or the cells would have to double in capactiy.

    I see three problems, all connected, size, cost, and charging time.

    At 320 kg, the VW batteries are heavy, and because of their use of cylindrical cells, they will be big. The Volt battery pack is big enough to reduce the interior space of the vehicle (built on the Cruze platform) noticeably. Of course, the whole thing scales linearly. If a 48 KWh battery weighs 320 kg, a 100 KWh battery will weigh twice as much. At some point you are dragging a lot of extra battery around for most purposes, so that you can have the extra range.

    Cost is also a problem. “… we’ll be looking at a commodity price of about 200 euro per kilowatt-hour. (Nissan’s batteries for the Leaf reportedly cost around 400 euro per kilowatt-hour).”

    The Leaf battery pack at 24 KWh will cost 9600 euros (~$12,500) which is a good chunk of the MSRP ($32,780). By using commodity batteries, VW can price their vehicle for less, but if they make the batteries bigger, the price goes up proportionately.

    Finally there is charging time. Nissan is saying the Leaf will take 8 hours to charge off a 220 line. Since a 220 line can move 20 KWh in about 3 hours, I assume that the longer time is intended to reduce strains on the battery cooling system. (Leaf may be air cooled). But, charging times for higher capacity batteries are subject to the same constraints. If you really wanted to put 96 KWh in your car, it will be an all day affair.

    • 0 avatar
      Paul Niedermeyer

      Robert; some clarification: Eberhard is projecting 500 mile range in ten years; the 3.4 mAh cells are as good as here now. The general assumptions are that energy density in batteries will at least double or triple in the next ten years. That means packs about the size of today’s will provide a 300-500 mile range, without any increase in pack size. He’s (rightfully) looking ahead; today’s batteries are still generally too constrained for prime time.

    • 0 avatar
      Robert Schwartz

      “Eberhard is projecting 500 mile range in ten years”

      And he figures that in ten years nobody will remember the prediction and to hold him to it.

      “The general assumptions are that energy density in batteries will at least double or triple in the next ten years.”

      I am very skeptical about that one. Chemistry gives some hard upper limits. The most energy dense lithium battery available right now is the Lithium Thionyl Chloride battery, which is not rechargeable. If a rechargeable achieved the energy density of the LTC battery, an 18650 cell would have between 4800 and 6400 mAh, which is not quite a doubling.

      The real issue given the limits on recharging speed, is whether it is better to use the increase in energy density to trade off battery size and weight. A 24 KWh battery pack with weighing 160 kgs might be a better choice, or using a 40 kg pack with 6 KWh in a series hybrid.

      “today’s batteries are still generally too constrained for prime time.”

      Yes, but higher capacity is not necessarily the answer. That may just lead to longer charging times.

  • avatar
    Corky Boyd

    Battery life is the Achilles heel of the EV. It’s not so much what the battery cost factor is for a new car, it’s the shock of replacing a 24 kWh even at $400/kwh ($9,600).

    We have become used to IC engines that last well over 100,000 miles. While the Leaf has matched the Volt’s 8 year 100,000 mile warranty, we don’t yet know the details. At what point does the warranty kick in? 50% of new battery life? Or 75%? Does the warranty transfer to a new owner when it is resold? A 5 year old Leaf should be worth about 35-40% of list. That’s less than $13,000. Is it worthwhile to buy a 5 year old Leaf with the prospect that 3 years down the road it may cost you $9,600 just to keep it running.

    Because of the financial uncertainty, any EV will essentially become valueless after the warranty expires if it still has the original battery. Not a plesnt thought.

    • 0 avatar

      “Because of the financial uncertainty, any EV will essentially become valueless after the warranty expires if it still has the original battery. Not a pleasant thought.”

      You make a good point – most people expect vehicles to last well over 100,000 miles, assuming proper care and maintenance. The battery pack (even if not abused) will fail simply due to “shelf life” constraints.

      I have a year-old Dell Mini 9 netbook whose %*&#* battery won’t charge at all because I left it idle in the bag for a few months – and Dell wants $100 for a new pack (GRRRR!).

      Another thought – cylindrical cells have a built-in cooling airspace around them, so that may be the reason – rectangular cells are potentially more energy-dense, but still need a cooling strategy that will reduce the volume available for cell chemistry.

      What may come out of this is a superior laptop battery, driven by the need for increasing range for EV’s. Sure as hell the laptop industry doesn’t give a damn when they can make big bucks on replacement packs (GRRRR!).

    • 0 avatar

      “You make a good point – most people expect vehicles to last well over 100,000 miles, assuming proper care and maintenance. The battery pack (even if not abused) will fail simply due to “shelf life” constraints.”

      There are 10+ year old Toyota Rav4 EVs running around with their original packs and well over 100,000 miles on the clock. Some are even at over 150,000. I rode in one the other day and it was like new in every respect.

      There is a world of difference between the abuse a laptop battery gets and the well-engineered battery management systems in a good EV.

    • 0 avatar

      “There is a world of difference between the abuse a laptop battery gets and the well-engineered battery management systems in a good EV.”

      There is also a lot of difference between the RAV4′s nickel metal hydride battery and the Roadster’s lithium ion battery.

    • 0 avatar

      “There is also a lot of difference between the RAV4’s nickel metal hydride battery and the Roadster’s lithium ion battery.”

      This is true, but the above statements were about EVs in general and not li-ion or anything else in particular.

      I know plenty of people with hard data to show the degradation is following predicted rates, not some “I bet it’s down to 100 miles in two years” type statement that seems to get pulled out of thin air.

    • 0 avatar

      “I know plenty of people with hard data to show the degradation is following predicted rates.”

      That’s what I would like to see. I’ve been looking for that data. Can’t find it.

      By the way, Elon Musk himself predicted that many people would want to replace their battery packs after two years due to reduced capacity.

  • avatar

    Martin Eberhard did actually start Tesla motors, and I say bring it on, my dumb car is always giving me trouble and I smell like oil and petrol all the time, electrics are ultra reliable cannot wait.

  • avatar

    … It’s going to take them 10 years from now to get 500 miles? I’ve read that the Tesla Model S have a 300 miles option. Isn’t there a con to high density?

  • avatar

    I don’t think I’d want an EV with 500-mile range. Even if they can get the cost, size and weight down, a 250-mile range EV will always be cheaper, lighter and have more room. And frankly 250 miles is PLENTY for day-to-day driving. Unlike my wife’s 100-mile EV, I don’t even look at the battery gauge on my Tesla in around-home driving, because it is always more than enough.

    The range is only an issue on the occasional road trip; and even then I don’t want to drive 500 miles without stopping! If I can go 200 miles and then stop at an L3 charger for 45 minutes to get a charge and eat, shop, stretch my legs, check my messages, etc I’ll be more than happy.

  • avatar

    I have 36,000 miles on my two year old Tesla. Range is down about 5 percent. Certainly tracks with the 20% loss Tesla predicts on a 100k use battery. For those who say they can’t find data, at TMC you will find that the larger percentage of Roadster owners are early adopters who own tech companies. (not celebrities).
    Those geeks have dissected and charted their battery performance extensively. The car has a USB port for downloading car history that also gives a superhighway of data to parse. Go to the Tesla motors club and root around. Just about all the owners there drive electric daily so it’s all there, the good, and the bad.

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