Tesla CEO: Super-capacitors Trump Electric Car Batteries.

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Elon Musk

Elon Musk

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What has a small Canadian low-speed vehicle firm and Tesla CEO Elon Musk got in common? 


Just like Zenn and the troubled EEstor supercapacitor firm,  Tesla CEO Elon Musk thinks that batteries are so last century. 

Talking at the Cleantech Forum in San Francisco on Wednesday this week, the 39 year old entrepreneur told the assembled audience that he’d bet on supercapacitors, not batteries, to deliver an important breakthrough in electric vehicle range. 

Unlike batteries, supercapacitors do not lose the ability to store charge with age. As a consequence they could potentially offer future where electric car owners are not faced with the worry of battery packs wearing out before the car does. 

Supercapacitors also have a much higher power density than batteries, meaning they can provide power far more quickly than existing battery technology. 



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With extremely high efficiency capable of supplying up to 95% of the energy used to charge it on discharging, a supercapacitor isn’t carrying around a dead weight of unusable capacity.

But there are significant problems with supercapacitors too. At the moment supercapacitors have a very low energy density, meaning they cannot store as much energy per lb of weight as a conventional lead acid or lithium-ion battery. In addition, supercapacitors discharge more rapidly in storage than batteries, meaning a stored electric car with a super-capacitor pack could run out of charge while in storage. 

Also, the voltage of a supercapacitor behaves much more linearly than a battery when discharged, meaning that a fully charged supercapacitor pack will suffer voltage drop more quickly than an identically sized battery pack. In order to make use of such a pack, complex power circuitry and management would be needed.

Even with these disadvantages, supercapacitors could very well cut our dependence on the humble battery pack. Simpler and faster to charge, longer-living and in some ways more versatile, supercapacitors are the holy grail of energy storage.

And Elon Musk Knows it. After studying high-energy capacitors as part of Ph.D work at Stanford University before co-founding Internet payment portal PayPal, his desire to include supercapacitors in a future Tesla electric car is obvious. 


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Comments (22)
  1. EEStor supercapacitors have just one small deficiency.
    They don't exist.

  2. good one!

  3. EEStor capacitors apparently work, but have not been
    made manufactureable except by hand. While batteries certainly are inferior to a battery, that doesn't mean that battery powered electrics can't replace ICE vehicles. The Model S proves that such a car is functionally capable of besting high end ICEs. High battery costs is the only barrier preventing electrification of the automobile.

  4. The pumpers of EESCAM like to spread LIES. EESTor's capacitor never existed. From the Air Force Research Lab:
    "Patent or not, he [Dick Weir] has never produced a prototype that anyone has seen, and there are good reasons he hasn't; the design approach is not feasible based on very basic physics and materials characteristics."

  5. Elon drinks the Kool Aid, LOL.

  6. Wonder why Elon Musk brought up this supercapacitor theme. Does he know something we don't or is that just what he wants us to hype Tesla stock value? Whatever...Fact is there is already battery technology out there that behaves a bit like supercaps in terms of C-rate. I'm talking about lithium titanate chemistry like Toshiba's SCiB battery. Charges in minutes and lasts for ever. Not very high energy density though. Also researchers at the University of Illinois have recently come up with new materials for battery cathodes that would essentially turn batteries in supercaps in terms of C-rate (up to 1000C!). Click my screenname for the article.

  7. Nikki, what did you mean by the word "troubled" when referring to EEStor? By the way, you sure have some mean-spirited readers out there, judging by the comments left here.

  8. EEStor always brings out ardent supporters and detractors, which I'm sure Nikki realizes increases page hits. Besides, it's a sexier topic than yet another lithium battery cathode material advance. ;)

  9. Mean spirited? Moi? I'm with Alex at #1. Show me some results and I'll be more than happy to eat my words.

  10. I'm afraid Musk is dreaming at this point. Batteries are getting better, EV's simply do not need the million charge cycle capability that caps provide, and caps are no where near competitive in price with batteries and have terrible energy density. Other than that.....

  11. Time to purchase Zenn stock? I would put a stop loss on this stock. I may talk to my broker about this stock.

  12. @Bob, EESTor has been in production mode the last 5 years. If you call Ian Clifford at Zenn Motor Corp, he will tell you how many super caps ZMC has received from EESTor.

  13. If you have any real awareness, the overarching reality is that any technology that challenges current energy economic empires and fiefdoms are DOA. If they were to be allowed we would all be owning our own zero point energy systems in our residences years ago. For one example of many, see Dr. Chang, U of Buffalo 1997 negative resistor. She is a world class materials Scientist whose discovery quickly became classified. She is not the first but one of many.

  14. You will buy my poisonous oil at whatever price i say for the rest of your enslaved lives... I hold the economic club of oil monopoly and i intend to beat you over the head with it and extort you until you are exterminated.

  15. As another article makes clear, the EEStor capacitor story will probably be relegated to the same history bin as the perpetual motion machine: http://www.greentechmedia.com/articles/read/eestor/
    Even better, is an old article that the Volt battery is cowering because of the EEStor battery potential. (The only problem is that the story is dated in July 2008!) It does make for humorous reading, though: http://tech.blorge.com/Structure:%20/2008/07/31/chevy-volts-batteries-cowering-as-eestors-supercapacitor-progresses/

  16. As you mention, low energy density, but fast recharge rates. Note that some Chinese City Bus lines are taking advantage of these qualities.
    Check out the basics here: http://www.evsroll.com/Capacitor_Explanation.html

  17. The cost of replacement batteries or supercapacitors must be included in the running costs of EVs before any true comparison can be made with the running costs of ICEs. If the life of my computer lithium battery is anything to go by EVs are on a loosing wicket!

  18. Time will tell. We are suppose to know more by the end of the year. I believe others have said we should know more by early next year. If nothing is produced by early next year. I believe Zenn stock may take a big dive.

  19. Been there, done this. You see auto gasoline engines have two phases, acceleration & cruise. It takes a lot of power to accelerate the vehicle, but only a few horsepower to keep it moving. The "problem" is if you lean-out the mixture on the big cube engine to less than 15-1 it sputters. The "Trick" is to accelerate the car with an electric motor, and cruise with a very small displacement gasoline engine. How you do this is with supercapacitors. You see I've actually tested this in my garage lab & it works perfectly. The numbers show better acceleration than a Corvette & 90 miles per gallon....Alfred-

  20. We should bring this technology to the people to reduce the cost and to save our planet as well as improve world economy.

  21. I think the combination of capacitors and batteries is the way to go. Use the capacitor to recharge the battery. It could be recharged quickly and used more for short term storage (Stopping and then restarting) Electric cars could be recharged as quickly as gasoline cars can be refilled.

  22. Ummm, yeah - - - the only problem w/the hypothetical super capacitor is that they tend to lose roughly 1/2 the energy they store during the charging process in heat and/or electromagnetic energy. 50% efficiency BEFORE we event get to the vehicle???? Build some more nukes . . .

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