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Fuel cells march toward the mainstream

Posted: 13 Aug 2002 ?? ?Print Version ?Bookmark and Share

Keywords:fuel cell? rechargeable-battery? mti microfuel cells? lithium ion? national institute of standards and technology?

After years of upping the technological ante, suppliers of micro fuel cells may finally be preparing to make a bid for the $10 billion-a-year rechargeable-battery market.

Their efforts reached a high-water mark this past week, as MTI MicroFuel Cells Inc. unveiled a prototype fuel cell that is small enough to ride piggyback on a cellphone, while offering greater charging potential than a lithium ion battery. The technology, said to be manufacturable because it employs no pumps or water recirculation techniques, could be in production as early as 2004, the company said.

MTI's 90cm3 device, reportedly the smallest direct-methanol fuel cell available, represents another in a succession of fuel cell advances during the past 12 months. Late last year, scientists at Motorola Labs demonstrated a prototype of a miniature ceramic-based direct-methanol fuel cell, a type that converts methanol fuel directly to electricity.

In April, Manhattan Scientifics Inc. unveiled a micro fuel cell that reportedly offers six to nine times the energy density of Li-ion batteries. And in May, Medis Technologies Inc. announced that its engineers had operated a tiny laboratory fuel cell at 0.5V and 10,000mAh continuously for 24 hours. Casio, Toshiba, and Samsung have also announced fuel cell breakthroughs in the past six months.

"There's an intense horse race going on now in the micro fuel cell area," said Gerald Caesar, program manager for the advanced-technology program at the U.S. Commerce Department's National Institute of Standards and Technology (NIST), which awarded $4.7 million to MTI for technology development last year. "If these companies can get the cost down, miniaturize the technology, and keep the energy density up, they have a real chance to supplant Li-ion technology."

Production effort

Fuel cells could represent a major step forward for the electronics industry, since they could be used as portable chargers for current-generation batteries or as power sources for cell phones, personal digital assistants or, eventually, laptop computers. There, they could eventually offer charge times anywhere from two to 10 times as long as li ion batteries, now the standard power source for such systems.

"Battery chemistries are reaching a point where it is going to be hard to enhance them much more," noted Barry Huret, president of Huret Associates, a battery consultant. "Fuel cells appear to be the next step, but it is clear that it is not going to be easy getting there."

MTI's announcement of a prototype that is believed to be the smallest direct-methanol fuel cell yet gave rise to speculation that fuel cells may finally be nearly ready for primetime. Direct-methanol fuel cells, which convert methanol to electricity through the use of a catalyst, are highly sought after by the electronics industry because they do not convert the methanol to hydrogen before creating electricity. That means such products as PDAs and cellular phones would not dissipate much heat and could, therefore, be held in hand or carried in a pocket.

MTI's prototype also added a new dimension, because the company's scientists said they have developed a conversion technique using a polymer electrolyte membrane that can easily be manufactured. Unlike past such techniques, MTI's system does not need to collect water from the fuel cell's cathode and pump it back to the anode, vastly simplifying the device's internal components.

MTI's claims of manufacturability were supported by the fact that the company is making obvious efforts to bring its fuel cell out of the lab and into production. DuPont, which has made an equity investment in MTI, is working with the company to develop membrane electrode assemblies and polymer-based conductive plates for use in its fuel cell stack. MTI also announced last week that it has hired Alan Soucy, a former Philips Electronics executive with experience in laptop and PDA production, to head a Silicon Valley operation that will develop alliances with the electronics industry.

Long-range potential

Micro fuel cells are said to offer energy densities of 1,000 watt-hour per kilogram or greater. By comparison, the best li ion batteries now range from 150W-hr/kg to 300W-hr/kg. As a result, some scientists believe fuel cells could boost the span between battery recharges by two, five or even 10 times on products such as laptops, cellphones, and PDAs.

"Depending on the application, we believe that we can get a factor-of-10 improvement in the useful life of a device between recharges," said Bill Acker, president and COO of MTI MicroFuel Cells.

MTI and other developers said they first plan to build fuel cell-based battery rechargers, which would recharge today's conventional batteries rather than replace them. Ultimately, however, they foresee their products' supplanting batteries during the next several years.

"Longer-use devices, such as PDAs and cellphone-PDA combinations, are the most attractive entry point," Acker said. "We are looking at high-end devices where the users are willing to pay a premium for the device itself, and pay a premium for longer usage times. When you bring out a product like this, you have to capture those applications first."

Observers said that the technology could be especially important for high-end cellphones, which are expected to climb from today's power draws of 1- to 3 W, up to as much as 5W in some cases.

"Once you start adding broadband capabilities to portable devices, you are going to dramatically reduce their run-time," said Caesar of NIST. "Phones could drop down to as little as half an hour of run-time in a 3G mode."

Using fuel cells instead of batteries to power such products, users would lengthen run-times as they shorten recharges. Fuel cells could be recharged simply by replacing a methanol fuel cartridge that would range from thumbnail size to the size of a bar of soap. Developers estimate that such refills would cost only about $1 apiece, and most of that cost would be contained in the plastic enclosure holding the methanol.

Hurdles ahead

Many experts contend, however, that fuel cell technology must cross several hurdles before it reaches the electronics mainstream. One key area of technical concentration is in their ability to handle temperature extremes as well as batteries currently do.

"Fuel cell catalysts do not operate very well in the cold, nor do they perform very well in extremely dry climates," said Bob Hockaday, chief fuel cell scientist for Manhattan Scientifics. "That is why some of the wild enthusiasm to put them right into electronic products has died down a little. That may still be a couple of years away."

Experts also said that the dream of fuel cell-based notebook computers may still be a few years out. "If you look at how people use notebook computers, you find that most of them do not run extensively on battery power," said battery consultant Huret. "Most of the time, notebook computers are plugged in, so the question could come down to how much more it will cost to give consumers the extra charge time."

Fuel cell makers said they still do not have a handle on how much the devices would add to the cost of a cellphone or laptop. As a result, manufacturers expect their technology to initially come out on higher-end products, where its cost can be more easily absorbed. They said they also need to tread lightly in the beginning while they build public confidence.

"The general public and the OEM engineers need to get comfortable with it first," said Acker of MTI. "The timing of our product rollout is going to be tied to developing the proper mindset."

- Charles J. Murray

EE Times

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