Firefly Energy Update
By Bill Moore
You can sense that Mil Ovan believes the company he helped spin off of heavy equipment maker Caterpillar is on a roll. It's obvious in his voice and in the flurry of email press releases being broadcast out of Peoria, Illinois. And when you've got a battery technology that could be a serious game changer, one that slashes the weight and increases the energy and durability of the most common automotive battery in the world, he probably has a right to be just a tad excited.
First, just as 2005 was closing, the U.S. Patent Office issued Firefly Energy a patent on its carbon foam and graphite foam battery core technology.
Next the company successfully recruited to its board of directors two senior executives from its parent, Caterpillar including its Chief Technology Officer and the head of its OEM Solutions Group.
Then, it was invited to make a presentation to a one-day energy independence conference in Chicago hosted by Senator Richard Durban where Ovan pitched the concept of electric vehicles and plug-in hybrids using Firefly batteries.
Finally -- and I had to wait until today before I could post this interview -- the company has just received $2.5 million in funding from the U.S. government to "ruggedize" its battery for military applications.
Phew... and it's still only January.
Okay, to briefly recap, the Firefly battery is a lead-acid-type battery where the solid lead lattices or plates, which are what make the battery so heavy, are replaced by lightweight carbon or graphite foam. This not only reduces the weight by half to two-thirds, but also greatly increases the effective surface area over which the electrochemistry of the battery can take place. According to Ovan this accomplishes two things: the energy density of the battery can be substantially increased, while eliminating sulfurization of the negative plates that prevents the battery from accepting a charge.
"If you're putting now a graphite material in these batteries that material is not corroding and participating in the chemistry like lead metal grids do.
"And second, there is always this quest for more power and capacity in a lead-acid battery," he stated. "Typically what one would do is if you want to put more chemistry in there, you'd need to add more lead grids in there to support that chemistry."
Traditionally, the only way to accomplish this and keep the battery the same size was to use ever-thinner lead lattices, but that then results in greater exposure to corrosion and accelerated shortening of battery life.
"By putting this now porous medium in there, you get the chemistry not only on top of the Firefly plate but within the pores of that foam plate, and now you can increase the surface area tremendously, number one; and number two, really minimize the distances over which the diffusion rates occur from millimeters in the classic lead-acid battery to microns instead.
"All totaled, those are really addressing some of the thresholds that have been set at a low level for lead-acid batteries. The chemistry, itself, is innately very powerful from a maximum theoretical standpoint, but there has never been an underlying grid surface that would take advantage of that innate power of the chemistry".
Ovan explained to EV World that the graphite core material, being more highly conductive, has application in hybrid batteries where power is needed for acceleration. The carbon foam battery is designed for more energy specific applications like a NEV or golf car-type battery.
For a 20-mile range plug-in hybrid, he sees a graphite foam battery being more suitable for that application than the carbon foam version.
Another benefit of Firefly's carbon foam core is its thermal properties and this played a part in the $2.5 million appropriation announced today in conjunction with Congressman Ray Lahood's office.
"Consider the situation abroad where temperatures in Iraq, for example, can reach 133 degrees Fahrenheit. There's kind of a rule of thumb in lead acid batteries that every 15 degrees you go above 70 Fahrenheit cuts the battery life in half, because it really aggravates and accelerates the rate of corrosion of the lead grid".
By "ruggedizing" its carbon foam core for military applications, Ovan believes this can spin-off into a highly durable, low-cost battery for the plug-in hybrid market.
"We're going to be making bigger batteries for the military than we are currently for Electrolux (their first customer), and it's those kinds of bigger battery and bigger battery packs that would be the ideal application for a plug-in hybrid.
Of course, there are other "horses" in the plug-in hybrid battery race, in particular lithium-ion. But Ovan points out that while lithium-ion has excellent energy numbers at the cell level, they require extensive cell monitoring circuitry that adds weight, volume and cost.
"When you talk about small cells, it's very impressive, but when you start scaling it up for large applications, now you're having to worry about putting a lot of electronic controls on it, thermal management for heating and cooling to keep it in a certain temperature range so the lithium battery doesn't degrade in its ability to perform. So, when you start to consider the volume and weight additions for these larger format lithium batteries, our view is that our performance tends to fall into the same kind of sweet spot, but without some of the limitations in terms of safety."
Ovan acknowledges that lead-acid has been dismissed for reasons of weight and durability, but he believes the rules of the game are changing, but he also admits that Firefly still has its "head down in development" and isn't yet prepared to declare "victory" just yet.
You can listen to the entire 16:35 minute interview using the Flash-based MP3 Player above or by downloading it to your computer hard drive for playback on your favorite MP3 device. [http://www.evworld.com/evworld_audio/firefly2.mp3].