Cedar Park Texas-based EEStor Inc. is an intriguing though secretive company to those who follow the development of electric cars. Although no known prototypes exist, they claim the ability to make extremely lightweight highly energy dense electric storage units (EESUs) that could revolutionize energy storage in electric vehicles. Indeed they have an exclusivity agreement to build EESU-powered ZENNergy drive electric vehicles with the Canadian company Zenn. Earlier this year it was reported that Zenn would receive production grade prototypes by the end of 2008. I asked Zenn CEO Ian Clifford whether that deadline would be met.

He said "the timeline for the delivery of an EESU is entirely within the purview of EEStor and as such I cannot comment on delivery timelines. I will restate that ZENN remain confident in the launch of an EEStor EESU (electrical energy storage unit) powered cityZENN by the last quarter of 2009."

In any event,on December 16th EEStor was granted a US patent for their EESU. The patent is a highly information-rich document that give a remarkable insight into these potential devices. EEStor notes "the present invention provides a unique lightweight electric-energy storage unit that has the capability to store ultrahigh amounts of energy".

The core ingredient is an aluminum-oxide(alumina)-coated barium titanate powder immersed in a polyethylene terephthalate plastic matrix. The EESU is composed of 31,353 of these components arranged in parallel. It is said to have a total capacitance of 30.693 F and can hold 52.220 kWh of energy. The device is said to have a weight of 281.56 pound including the box and all hardware. Unlike lithium-ion cells, the technology is said not to degrade with cycling and thus has a functionally unlimited lifetime.

It is mentioned the device cannot explode when being charge or impacted and is thus safe for vehicles.

The patent describes in explicit and complex detail how these basic ingredients are prepared and combined to create the EESU using screen-printing and layering techniques.

Read Full Patent HERE .

It seems to me this patent is rather elaborate for anything disingenuous, and perhaps they've really got a genuine breakthrough after all. Hopefully, we shall soon see. Clifford once told GM-Volt.com he's met with GM and said "a Volt with a ZENNergy drive is a kind of a sexy product. You never know. It would certainly be something we’d love to explore."