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Posted on September 8, 2004 by  & 

Fuel cells for RFID

The need for power

As chips have become more complex, their thirst for power gets ever more insatiable. When it comes to wireless gadgets, battery technology has not managed to keep pace with other innovations.
 
One option is for batteries to be replaced by fuel cells. Both Fujitsu and Hitachi have proposed using fuel cells in laptop computers within the next few years. The aim is that electronics manufacturers will be able to deliver fuel cells that stay powered longer than the conventional lithium ion batteries used now.
 
MTI MicroFuel Cells, a division of Albany, N.Y., recently announced plans to develop a fuel-cell concept it calls Mobion that can be used in handheld electronic devices such as cellphones and PDAs. The result, according to the company, will extend the length of time such devices can run on a single charge by three to ten times, compared with a comparably-sized battery.

How does a fuel cell differ from a battery?

There are fundamental differences between fuel cells and batteries. Batteries store energy using chemicals, however fuel cells use chemical reactions to create electricity. MTI builds a type of fuel cell called a direct methanol fuel cell (DMFC), which mixes methanol and water on one side and air on the other, separated by a membrane.
 
 
Water is the problem
 
In most cases of such cells, the water in the process is circulated around the power cell where it is mixed with methanol. Moving the water around requires pumps that increase the overall size of the power cell and decrease its overall efficiency. MTI's Mobian approach uses a method that internally manages the flow and entirely dispenses with the need for pumps.
 
When the DMFC runs out of power, instead of plugging it in to recharge, it is replaced just like traditional batteries, although it has a far longer life.

Useful for active RFID tags and readers?

If the market for fuel cells does take off, MTI is ready. It has enlisted heavyweight partners to help ramp up production and distribution. Gillette, maker of the Duracell brand, will manage the distribution of refills. Contract electronics manufacturer Flextronics International will handle manufacturing, and DuPont is in charge of assembly of the membrane.
 
MTI Chief Executive William Acker says the first products will be aimed at industrial applications. Intermec, a maker of RFID readers and a unit of Unova, will be the first company to use a Mobian fuel cell, starting later this year. Consumer applications should follow by around 2006 or so, according to Acker.
 
 
That just happens to be about the time when analysts predict the market for fuel-cell-driven consumer devices will take off. Sara Bradford, analyst at Frost and Sullivan in Boston, expects the number of fuel-cell shipments to break 20 million by 2007, and rocket to 120 million units by 2010.
 
Acker says another potentially huge application lies in military use. "Soldiers are being sent into battle with so many batteries to power all their gear. Fuel cells would lighten their load," he says.
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