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

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  Le Petomane
  

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  09/19/2007 06:22 PM

  Okay, I did a little research on Pure Barium Titanate

  Much of the talk and dissent is above my head. One thing stands out when I research PURE Barium Titanate. It has dielctricl properties that are/were unexpected and the research is in it's infancy. We are dealing with nano-technology in regards to EEStor claims. The world is mighty different at that scale.
  
  Have any of the naysayers worked with Pure Barium Titanate? I'm not saying your wrong, just wondering if there's more going on than some of you may be privy too.

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  • 
    CapacitorMan
    

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    09/24/2007 10:06 AM

    Re: Okay, I did a little research on Pure Barium Titanate

    Yes, the availablity of really pure BT has improved over the last few years, and it does have interesting properties. As a very pure material it has a higher permittivity then normal purity (99.99%).
    
    But, heres the thing. It is a lousy commercial dielectric because it has a peak capacitance at about 100°C,similar to "normal" BT. Other oxides are added to reduce the K, and make it more stable with temperature and voltage.  So when you have to add 15-20% of other oxides to it, it makes mute the difference between 99.999 and 99.9999% purity, not worth the order of magnitude increase in price.
    
    There is some improvement that carry over, so it demands the BT be a reasonable purity, which varies with the end use.
    
    On your "rail gun" discussion, the patent office is required to have the defense department (and now probably homeland security) review any patents related to high energy phenomena. They actually have special rules that kick in, and the patent, if real, will not be published.
    
    Kind of gives you a warm feeling doesn't it?
    
    Good questions!

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    • 
      Le Petomane
      

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      09/24/2007 04:04 PM

      Re: Okay, I did a little research on Pure Barium Titanate

      Really! That does not give me a warm an fuzzy. That should be VERY public knowledge.

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        CapacitorMan
        

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        09/25/2007 11:58 AM

        Re: Okay, I did a little research on Pure Barium Titanate

        From the Patent Office Manual:
        
        “…35 U.S.C. 181 which provides, in part:
        
        Whenever the publication or disclosure of an invention by the publication of an application or by the granting of a patent, in which the Government does not have a property interest, might, in the opinion of the Commissioner of Patents, be detrimental to the national security, he shall make the application for patent in which such invention is disclosed available for inspection to the Atomic Energy Commission, the Secretary of Defense, and the chief officer of any other department or agency of the Govern¬ment designated by the President as a defense agency of the United States.
        
        If the agency concludes that disclosure of the invention would be detrimental to the national security, a secrecy order is recommended to the Commissioner for Patents. The Commissioner then issues a Secrecy Order and withholds the publication of the application or the grant of a patent for such period as the national interest requires.”

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        • 
          Le Petomane
          

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          10/04/2007 02:39 AM

          Re: Okay, I did a little research on Pure Barium Titanate

          I can't know how to say it elegantly, but that's messed up.
          
          Okay, I'm a bit of a conspiracy theorist and that just adds fuel to my fire. There's so much DoD is hiding.
          
          And I forgot to add one of my favorite quotes. Conspiracy is not a theory, its a crime.

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          • 
            NOX813
            

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            10/08/2007 06:45 PM

            Re: Okay, I did a little research on Pure Barium Titanate

            A little paranoid?
            Humping 16lbs of batteries in 120 degree temperatures is not a way to make soldiers small targets, it slows you down-a lot. The military has no interest in giving tech a back seat to the 10's of millions of dollars already given to solve this problem.
            If you think differently then you really need to have the experience of humping them around. A rail gun is a cool tool, but not as effective as a SOGer with a grid and help from his friends at 35,000 feet.
            Rail guns are a 140,000 ft plus tech, held within heavy lift hydrogen envelopes, shooting ceramic pellets aimed by capsuled forces with real time high def optics and laser/radar targeting.
            
            Get a grip and a clue!

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              Le Petomane
              

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              10/30/2007 02:48 AM

              Re: Okay, I did a little research on Pure Barium Titanate

              You apak only of rail guns mounted on ships, which this technology is appropriate for. I have seen small scale rail gus that are almot portable.

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  ancient_nerd
  

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  09/30/2007 07:23 PM

  Energy Density is the bottom line

  Getting a high dieletric constant is about a third of the battle.  The rest is dieletric breakdown.  The energy stored in a capacitor is
  e=(cv^2)/2.
  We can double the maximum v by doubling the spacing between plates.  But, this cuts c to a quarter of its original value.  We can fit only half as many plates in a given volume.  In the formula for capacitance, the area is cut in half and the height is doubled.
  With a relative permitivity of 18500, I get a field strength of about 700 volts/micron to match the energy density of gasoline.  This sounds like a lot.  To get this between the plates, it will be much higher at the edges where the flux lines are not parallel.
  Eight gallons of gasoline represents about a gigajoule or 278 Kwh.  They are proposing to store only 15 kWh.  Since the break we get is the square root of the ratio, We are down to about 1/4 of the field strength or 175 v/um.  Does anyone out there know what the conventional ceramics can withstand?
  On an atomic level, the field pushes the electrons to one side of the atomic nuclei.  Breakdown occurs when they are pushed so hard that they break free.  If the voltage is across the particle coating, the barium titanate inside is not storing the energy.

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  • 
    kd4uk
    

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    10/08/2007 10:46 AM

    Re: Energy Density is the bottom line

    O.K. I have been reading just about all the comments and opinions on this subject . But I have not forgotten that Pres. Weir said he would deliver the first working system to the Canada based electric car co . this year - and its running out ! Has the DOD stepped in and sat on it ? Whats going on . Give us a clue Mr. Weir ...

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    • 
      ancient_nerd
      

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      10/18/2007 02:48 AM

      Re: Energy Density is the bottom line

      It is not some conspiracy by the DOD or anyone else.  It is another attempt to overrule the laws of physics, with the usual results.  VC's are essentially high rolling gamblers.  This guy would improve his odds if he extended his mathematics beyond accounting.  He needs to actually calculate energy before he spends his money.

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