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EEStor Announces Two Key Production Milestones; 15 kWh EESU on Track for 2007

17 January 2007

EEStor, the developer of a new high-power-density ceramic ultracapacitor (the Energy Storage Unit—EESU), has broken a long public silence and announced reaching two key production milestones. First, its automated production line has been proven to meet the requirements for precise chemical delivery, purity control, parameter control and stability.

Second, EEStor has completed the initial milestone of certifying purification, concentration, and stability of all of its key production chemicals—notably the attainment of 99.9994% purity of its barium nitrate powder.

The independent 3rd party chemical analysis was completed by Southwest Research Institute, Inc. located in San Antonio, Texas under contract with EEStor, Inc.

With these milestones completed, EEStor is now in the process of producing composition-modified barium titanate powders on its automated production line, and is moving toward completing its next major milestone of powder certification.

The company anticipates that the relative permittivity of the current powder will either meet and/or exceed 18,500, the previous level achieved when EEStor produced prototype components using it engineering level processing equipment.

The EEStor ESU is projected to offer up to 10x the energy density (volumetric and gravimetric) of lead-acid batteries at the same cost. In addition, the ESU is projected to store up to 1.5 to 2.5 times the energy of Li-Ion batteries at 12 to 25% of the cost.

According to the company’s initial patent, the EESU is based on a high-permittivity composition-modified barium titanate ceramic powder. This powder is double coated with the first coating being aluminum oxide and the second coating calcium magnesium aluminosilicate glass.

The EESU alternates multilayers of nickel electrodes and the high-permittivity powder. The resulting parallel configuration of components has the capability to store electrical energy in the range of 52 kWh, according to the document, with weight for a unit of that capacity in the range of 336 pounds (152 kg).

According to EEStor, the EESU will not degrade due to being fully discharged or recharged, and also can be rapidly charged without damaging the material or reducing its life. The cycle time to fully charge a 52 kWh EESU would be in the range of 4 to 6 minutes with sufficient cooling of the power cables and connections.

The first commercial application of the EESU is intended to be used in electric vehicles under a technology agreement with ZENN Motors Company. (Earlier post.) EEStor says that it remains on track to begin shipping production 15 kWh Electrical Energy Storage Units (EESU) to ZENN Motor Company in 2007 for use in their electric vehicles.

The production EESU for ZENN Motor Company is designed to function to specification in operating environments as severe as -20° to +65° degrees Celsius, will weigh less than 100 pounds, and will have ability to be recharged in a matter of minutes.


January 17, 2007 in Batteries, Electric (Battery) | Permalink | Comments (86) | TrackBack (0)


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Thanks for the news!

Free PS3

EEStor has promised working models in 2007. Not long to go. Proof will be in the pudding.

I am willing to wait and see if they can do it. It they do what they have claimed, then everything will change in world of power storage. The possibilities are endless if they succeed. I think what they are really doing is not covered in their patents and like many previous inventions they might actually have invented something that did not previously exist. Without all the information we are all just just guessing at what is behind the curtain. I will give Richard Weir and his company the latitude to deliver their product sometime next year.

Sean McDonald

Below is a detailed discussion clearly demonstrating the invalidity of EEstor’s claims and targets.

EEstor does not report either a new material, or any data that indicates the ability to store more energy than known titanate dielectrics. EEstor calculates the amount of energy they expect their capacitor to store. A fundamental oversight results in an invalid calculation that is inaccurate by more than a factor of 100! The error is uncomplicated. Simply, energy does not equal ½ CV2 for a capacitor made from a nonlinear dielectric. For all high permittivity ceramics, the dielectric permittivity (K’) decreases markedly with increasing electric field E (dielectric saturation). Energy increases roughly linearly with voltage for these materials, as opposed to with the square of the voltage (ref 2).

Importantly, this is not a case wherein EEstor claims to have made some specific breakthrough regarding this issue. No such breakthrough is reported. There are no energy storage measurements, no permittivity versus field data, and no mention of eliminating or reducing dielectric saturation. Their patent and presentations indicate a complete lack of awareness (or lack of acknowledgment) of this issue. EEstor simply purports to make (or aspires to make) high K barium titanate based material, with a K of 18,000, and ultimately with an incredibly high breakdown strength of up to 300V/um. They then calculate the energy stored as ½ CV2 without comment on the use of this equation.

How large of an error does this cause? Calculated energy density is ½K’E2 when calculated total energy is ½CV2. For K = 18,000, and a field 100 V/um, this invalid calculation gives 800 J/cc. (½K’E2 = (0.5)(8.85x10-12 F/m)(18,000)(1x108 V/m) = 8x108 J/m3 = 800 J/cc). Eight references describing actual studies of energy storage in high permittivity ceramic dielectrics (including barium titanate and BST) are noted below. All of these studies indicate a maximum energy density ranging from about 2 to 12 J/cc, depending on the exact material and the maximum breakdown voltage (which is on the order of 100V/um in most cases). Notably, for the studies involving very high K materials, if the authors had simply calculated energy storage using ½ CV2, as EEstor does, it would have similarly resulted in reported values on the order of 100 times greater than the actual measured values!

Hence there is no basis for concluding EEstor has made any advance in the field, and clear evidence that the sole basis for their claim of unbelievably high energy storage is the simple, invalid calculation. Their aspiration (with no reported results) to triple the breakdown field to 300 V/um in combination with the invalid calculation adds an additional factor of 9, giving an absurd 7200 J/cc (along with all of the corresponding hype and speculation about a new miracle material).

Below are notes regarding the references noted above that clearly substantiate the analysis above (one report of personal measurements, the other seven directly from a Google search on energy storge in ceramic dielectrics). .

1. (My work, unpublished), 1987 – Report to Maxwell Corporation on energy storage potential in high permittivity ceramics. Measurements were made on thin films up to 100V / um on barium titanate and PLZT based dielectrics. K varied as ~ 1/E over much of the voltage range, resulting in an approximately linear increase in energy density with field. Maximum energy storage was 4 – 8 J/cc.

2. Love, Journal of the American Ceramic Society 1990 – Also observed a linear increase in energy with voltage for several classes of high permittivity (up to 12,000) thick film ceramics (barium titanate, PLZT, PMN). Reported up to 5 J/cc at 80 V/um.

3. Triani,, (ANSTO and CSIRO – Australia, 2001 – J. Materials Science and Engineering. They reported 8 – 10 J/cc for PbSr titanate, and noted that the energy densities were similar to those of the best BaSr titanate materials for a given field, but the maximum fields of up to 100V/um (100KV/mm) were superior for the PST.

4. Kaufmann, et.,al, Penn State and Argonne, 1999. DOE Contract Report. They report sputtered BaSr titanate thin films with a K of 500 and a breakdown field of 100 V / um. K decreases to 120, and the energy storage is 11 J/cc. Also reported are data for hot pressed AFE/FE lead zirconate. These had a maximum K of 12,000, and a breakdown strength of 12 V/um, resulting in an energy storage of 3.2 J/cc.

5. Fletcher,, 1996 Journal of Applied Physics D. They report a theoretical analysis based on Devonshire theory of ferroelectrics. Optimal energy density is predicted for materials with Curie Temperatures well below the operating temperatures. Applied to BaSr titanate, the model predicts an energy density of 8 J/cc at 100 V/um. The model was verified in actual materials.

6. Randolf, et. al, (Austria, 1996) – IEEE Annual Report - Studied dielectric energy storage for powders embedded in polymer matrices. They reported using a PbTitanate-PbZnNiobate material with K = 5000, and reported energy densities of 1 – 10 J/cc.

7. Lawless, et. al., Ceramphysics Inc. 1992 report a high permittivity ceramic (K = 8000) for which a maxium energy density of 6 J/cc was observed for samples with optimum breakdown strength.

8. Freim, Nanomaterials Research Corp NASA SBIR Proposal 1998, reports reduced dielectric saturation for nanocrystalline microstructures, and states that “Commercial coarse grain dielectric based ceramic capacitors are ineffective for use in high energy storage and delivery applications since the dielectric's permittivity decreases sharply when the applied voltage is increased.” They target 5 – 10 J/cc for the proposed new improved materials.

Just a few additional points. Doesn't it seem a little obvious and transparent that the whole incredible story is about energy storage, but they never provide a measurement of energy stored. All of the announced milestones relate to higher purity powders, and permittivity targets, and manufacturing scale up (which no doubt requires funding). It would take two days to make a small thick film sample or a polished down pellet, measure permittivity versus field, and calculate energy density. Why do you suppose they never do that? Could it be because when you just measure permittivity and declare that the energy in your capacitor will be 1/2CV2, you get > 1000J/cc, but if you make a small pellet and measure it you get 5 J/cc (and no more funding). You figure it out

Top 5 reasons to not show your cards this early:
5.) Avoid the Segway pre-release hype fiasco.
4.) Same reason the guys who invented artificial diamonds were very secretive and received many death threats: Massive incentive to do them harm by worlds largest industry.
3.) Revealing anything won't help your business. Money is not in short supply to create their own mega-business when things happen so why tell anyone anything.
2.) Details provide competitors shortcuts to replicate.
1.) Public proof isn't a prerequisite of selling tens of millions of cars to Joe Sixpacks or Li Wongs, only the manufacturers and their cash suppliers "need to know".

One year on and we're still waiting. Oh well.

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