Company’s carbon chemistry a fine fit for stop-start

  • 17-May-2011 04:36 EDT

Axion's founders, including CEO Thomas Granville (pictured), purchased the base patents for the company's PbC technology in 2004.

Thanks to some luck, a Pennsylvania company may find the automotive industry a bigger and better market than expected for its patented battery technology.

Luck had nothing to do with Axion Power International Inc.’s promising chemical formula, nor with the fact that the start-up acquired a plant so it could fully develop and produce the product, which initially was targeted at utility and industrial energy-storage applications.

“What we didn’t foresee is that the European Union would pass legislation in 2009 that requires a reduction in CO2 from current levels to 130 g/km and requires the phase-in to begin in 2012 and be 100% implemented by 2015,” said Thomas Granville, the company’s CEO and one of its founders.

With that, an automotive market (stop-start micro and mild hybrid) materialized for Axion’s PbC branded activated-carbon negative electrode technology.

Granville tells the company’s story from his office in New Castle, PA, as chemists, engineers, factory workers, and others work nearby to realize what he believes is Axion’s great promise.

“What we’re doing here is replacing the lead negative electrode with an activated-carbon negative electrode,” he explained. “The negative electrode is the main failure mechanism in a lead-acid battery, and the reason it fails is because the lead on that side sulfates and sheds and causes end of battery life.”

Activated carbon (carbon with much greater porosity and surface area) provides unique and favorable properties, said Granville: “It lasts three to four times longer in deep-cycle applications and it has much greater charge acceptance. Everything else is the same as a standard lead-acid battery: the case, the cover, the separator material, the electrolyte. You can’t tell the difference between this battery and your old car battery until you pick it up; it’s 30% lighter.”

And a perfect fit for start-stop applications, where the battery needs to recharge quickly, said Granville. He said Axion’s technology allows for recharging in an 8 to 16 times shorter (depending on battery state of charge) period of time than conventional lead-acid batteries.

The base patents for the technology were developed in Russia and brought to Canada by C&T Technology about 10 year ago. Axion’s founders purchased the patents in 2004 and further developed the technology with the idea that the company’s main product would be the negative electrode, not batteries. Nine patents have been issued for the technology to date.

“We don’t want to be just a battery company and compete with China and the giants of the battery world like Exide and Johnson Controls. That does not make business sense. Exide, for example, is in 80 countries. Well, we don’t want to do that. We eventually want to make this proprietary product that other lead-acid battery companies can put into their batteries,” Granville said.

The company has been producing demonstration-project quantities for about a year and a half, he continued, “but we continually tinker with the product. We can change the plate configuration, the plate counts, and we can move either toward more power or more energy. It’s really a hybrid supercapacitor. We can gear it more toward the power of a supercapacitor or the energy of an actual battery.”

Some lead-acid-battery competitors use carbon-based technology, said Granville, but can’t match the Axion product’s charge acceptance. The charge acceptance for other lead-acid batteries, which today starts at 50 amps, drops below 10 amps after about 4000 cycles.

“In stop-start, 4000 cycles equate to about five months, six months,” he said. “Conversely, our product at 70,000 cycles still accepts the full 100 amp charge, and that’s because [in conventional batteries] the lead crystals form hard rocks after a period of time; they don’t convert back to lead, and as a result of that you can’t charge them as quickly or in some cases can’t charge those really hard rocks at all, whereas you can continually charge the activated carbon.

“It really almost acts like an atomic sponge, and it’s because of the huge surface area of activated carbon. A piece of activated carbon about the size of this business card has a surface area that’s almost as large as a football field. It has a lot of nooks and crannies in its subatomic structure.”

There are other non-lead-acid chemistries that compete in hybrid vehicles, including lithium-ion, nickel metal hydride, and some types of supercapacitors, Granville said. “But they are all significantly more expensive.”

The larger market for the PbC product is energy storage, but the nearer-term market is automotive, Granville said.

Axion jet-mills the carbon itself. “That’s a proprietary process,” Granville said. “There’s a lot of activated carbon out there in the world. You have to know what the right combinations are, and that’s where the chemists come in.”

Axion does chemistry and engineering right alongside production of the electrode, full batteries with the new electrode, and conventional lead-acid batteries in a building northwest of Pittsburgh previously owned by a failed lead-acid battery maker.

Granville said it’s proven very beneficial to have its own production facility to try out innovations and to produce the new batteries in what quantities it chooses. Other companies (and Axion itself before purchasing the New Castle production facility) have found it difficult to buy time on larger battery makers’ production lines to trial innovations.

Production of PCB electrodes currently is limited, with one automated robotic line. Plans are to eventually have 10 lines up and running at New Castle and many more at licensed battery makers throughout the world.

But first Axion must prove the technologies to customers, and to that end it is working with several OEMs, among them BMW.

“We jointly presented with BMW in Istanbul at the largest lead-acid battery conference in the world,” said Granville. “We’re told they have never presented with a suppler or endorsed a supplier’s product in the past, but in our case they felt that it was very important for the other OEMs in Europe to understand that AGM [absorbed glass matt] lead-acid batteries aren’t going to work to meet EU CO2 regulations.”

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