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This discussion relates to Technology Review's article Battery Breakthrough?.

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  MartinH
  

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  01/27/2007 05:21 AM

  BASF Patent 7023687

  I was looking around to see if there was other work been done on  creating high energy ceramic patents and I am interested in seeing comments on this one.
  This is a patent from BASF regarding a Barium Titanate Capacitor that can be charged to 200v  and have an energy density of 5.5kwh/liter!. This sounds somewhat superior to the eestor though they dont specifically outline the energy density per kg.
  It configuration is a somewhat different from EEstor version it seems have a first a conductive layer then a layer of Barium Titanate and then another conductive layer, as opposed to the insulating layers that eestor is using.
  BASF research into ceramic capacitors is mentioned on its future business pages but without any details.
  http://www.basf-fb.de/en/futurebusiness/themen/energiemanagement/projekte.htm?id=V00-X7Cow9w.2bw21d0#2
  Anyway I have not seen the BASF patent mentioned in discussions of eestor and would like to see what others think of its potential, particularly as BASF is a fairly substantial company.
  

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  • 
    CJC_PE
    

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    01/27/2007 03:45 PM

    Re: BASF Patent 7023687

    The energy density (kwh/liter) of the capacitor described in the BASF patent seems to be about twice that of the EEStor capacitor. However the patent does not provide an estimate of the size of the largest individual capacitor cell that can be manufactured or discuss the feasibility of connecting large numbers of cells in parallel. The ability to achieve a high energy density in a capacitor charged to 200 volts rather than 3500 volts would be an advantage for some uses but 200 volts might not be enough for an electric vehicle. The motor voltage must be considerably less than the fully charged voltage to allow for the reduction in capacitor voltage as the stored energy is used.

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      jhbretz
      

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      01/29/2007 08:34 AM

      Re: BASF Patent 7023687

      I'm a power electronics design engineer, and I did a Dodge Neon EV conversion with a friend in college.
      
      I think that operating at 200V max is quite reasonable.  Since the energy in a capacitor is proportional to V^2, 3/4 of the energy is between 100V and 200V.  Some power topologies (direct i.e. not flyback) can either boost or buck, so the motor drive could still run at ~150V.
      
      The fact that BASF also patented this technology means there is probably be something to it.  I was skeptical, but now I'm really excited.
      
      Electric chargers at existing gas stations could have their own ultracaps in the "pump" along with the power electronics to deliver a high constant current.  ***Rough*** numbers here, 100F at 500Vpk in the car would need 300Adc for a 2 minute quick charge from 100 to 500V.  300Adc is very reasonable for a fixed installation.  In fact, the EV itself could draw this much current during acceleration at low charge voltage.  Your home charger would only need 5-20Adc (constant power output) for a 1.5 hour charge, running off of a clothes dryer plug.

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      • 
        CJC_PE
        

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        01/29/2007 10:01 AM

        Re: BASF Patent 7023687

        I agree that capacitive energy storage at 200V is feasible for EV use, but I think a little higher voltage would be preferable and it would be preferable not to boost the voltage.
        
        Your charge time example only provides 3300 watt hours. That is only enough to deliver 10 Hp at the motor shaft for about a half hour.

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          elecdrivr
          

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          01/29/2007 12:35 PM

          Re: BASF Patent 7023687

          I have a home converted Honda Civic running on 120v DC, and would be happy to replace 800lb lead acid with capacitors at 200v. Roll on the tape capacitors!

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          jhbretz
          

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          01/29/2007 04:40 PM

          Re: BASF Patent 7023687

          You're right - not enough energy in my charge time calculations - I had 12.5MJ (3.5kW/hr) in the pack, but this is only about a 20 mile range.  So x10 and you have a 200 mile range with 1kF at 500V peak charge (1kF - is that possible - I guess that's the question) and to charge it from 100V to 500V in 5 minutes would take 1300A.  This is too much current for any reasonable charger cable.
          
          Maybe this is why EEstor went with 3.5kV peak cap charge.  Now for the same energy storage as above (35kW/hr, which costs $5, or about $1 per equivalent gallon), to charge 20F from 0.5kV to 3.5kV in 5 minutes takes only 200A.  This has 42.5 times lower loss in the charger cable and internal series resistance.

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    john2
    

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    02/01/2007 09:29 PM

    Re: BASF Patent 7023687

    That patent does not seem real either. They do not claim having made any real part, but simply say that if their part were made, the calculations show that the capacitance would be 10FARADS and the voltage could be 200 volts on a 0.1 micron dielectric.
    
    This is crazy...again, the voltage is way beyond what the dielectric can take, and that high a field, if it did not short the capacitor, which it would, the net capacitance would be about 5% of what they claim.
    
    When a patent admits not making a real part, I would be suspicious if I knew nothing of the system, which I do.
    
    Sorry, thats not the answer either

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    • 
      d3adp00l
      

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      02/06/2007 01:11 AM

      Re: BASF Patent 7023687

      I read almost every post on this, including the long one. Scary thing is I understood most of that one, I wonder what that means, either I am insane or I guess nutts. I see a lot of "claims" in many areas (not only here), and I had a strange, radical idea of my own. Build something that works, test it, record the data, get a patent, then produce it. I know its a revolutionary process, and will be met with critism, but what the hay. BTW about the patent filings, there are many patents on things that don't work, and many things that work with no patents. I wish people would stop trying to secure their "rights" so much and just build their damn ideas.

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  Danbob
  

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  01/29/2007 09:48 PM

  charging power

  It would be great if this works but were are they going to get the power to charge all of these caps? I live in Seattle and we have a lot of cheap power but I know of a lot of commercial property that is available in completed business parks that can not be sold because the electric company can not supply the power they would need.

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  • 
    CJC_PE
    

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    01/29/2007 10:03 PM

    Re: charging power

    What is proposed in the EEStor patent is that charging stations would have banks of ultracapacitors that would be charged at night at a steady rate when usage is lower and transfer the charge to vehicles whenever needed. That would help, but it is only part of a solution to one of the problems involved in developing the infrastructure needed to support widespread use of electric vehicles.

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    • 
      banrjeer
      

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      01/30/2007 02:46 PM

      Re: charging power

      Charging time will not be an issue for people with garages. That a significant chunk of the market. charging does not need to be instantaneous when parked in a garage.

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