- 08 April, 2003 09:13
Today's digital devices are smaller and more powerful than ever, but a roadblock obstructs further miniaturization: the batteries. Manufacturers can produce smaller notebooks, mobile phones, and PDAs, but today's cumbersome power sources make the small packages impractical.
That roadblock may soon be lifted: Over the next year or two, new technologies could bring better batteries and even better fuel cells. Many industry insiders consider fuel cells, which create electricity through a chemical reaction, the power source of the future.
But don't recycle your batteries just yet. Fuel cell technology remains in its infancy, and products that use it aren't expected until next year at the earliest. Even when fuel cells become widely available, experts believe that the technology will coexist with today's traditional batteries.
Small, relatively simple fuel cells that use methanol as their primary fuel could appear in mobile devices as early as next year. Fuel cells don't require recharging: When they run out of power, you simply replace the empty methanol cartridge with a full one.
These cartridges will pack a lot of energy.
"Methanol has 40 or 60 times the energy efficiency of lithium ion," the primary storage component of the best batteries, estimates Dr. Brian Barnett, managing director of the TIAX LLC consulting firm.
But the gains in energy density may be less dramatic at first. Early fuel cells will probably have as much as a 5-to-1 advantage over similar-size (but heavier) batteries, Barnett says. Theoretically, the ratio could increase to 10-to-1 as the technology improves.
Almost all of a battery's mass consists of the chemical compounds that generate electricity, but a fuel cell requires some extra baggage. Only part of a fuel cell can store methanol; the cell must also accommodate a chemical engine, where hydrogen from the methanol combines with oxygen to generate electricity.
To double the energy capacity a standard battery, you would have to make the battery twice as massive. But with a fuel cell, the more methanol you can store, the longer it will provide power. That's why early fuel cells may look similar to today's batteries in size, but will weigh less.
Fuel cells need their own batteries. Most portable devices have varied power demands, requiring a large flow of electricity at certain times and a tiny trickle at others. Batteries handle this variety well, but fuel cells tend to produce a steady stream of juice. The answer is to provide both a battery and a fuel cell, so the device can draw from the battery when demand is high, and run off the fuel cell when demand is lower. The fuel cell could be used to recharge the battery, depending on need.
Alternatively, a device could use a rechargeable battery for short stretches of time to save the fuel cell under certain circumstances, according to David Dorheim, chief executive officer of Neah Power Systems, which is developing small-form-factor fuel cells.
Maximum Security Cells
Bringing fuel cells into the mainstream won't be easy: One problem is airport security. Methanol is a flammable liquid, and the government is understandably reluctant to let anything on a plane that could be used as a weapon.
"We're working with the Department of Transportation to figure out how you'll be allowed to bring them on a plane. People still carry Bic lighters onto planes, which are far more flammable than (fuel cells)," says Bill Acker, president and CEO of MTI Micro, which hopes to market fuel cell technology to notebook and gadget manufacturers.
There's also the issue of buying fuel. How much those cartridges will cost is anybody's guess. Methanol itself is cheap--as little as 40 cents per gallon--but when you add cartridge manufacture, distribution, and other expenses, the price becomes impossible to nail down. Neah's Dorheim, however, predicts that with high-volume manufacturing in place, cartridges used for mobile computers will likely cost consumers around US$2 to US$3 each.
Price isn't the only issue. Fuel cells will be at a serious disadvantage until the cartridges become more readily available, which won't happen until the products begin to gain market share. That, in turn, isn't likely to happen until the industry standardizes on a few cartridge types.
Unfortunately for users of battery-hungry electronic gadgets, the technology will take some time to develop. Even optimistic developers don't expect fuel cells to begin appearing in consumer devices and notebooks before 2005.