Since 1985, when Toshiba first introduced notebook computers, it seems like everything about the laptop has improved -- except for their batteries. Screen displays have increased from 10 inches to today's standard 14 to 17 inches. Processors have become more powerful, and designs are more lightweight and user-friendly. Alas, that still-clunky battery always seems to die after about two hours of use, with a few shrill warning beeps.
Actually battery power and performance have seen some improvements over the past few years. The problem is, they just haven't kept up with the demands of today's devices. It isn't just business users who now must cart suitcases full of rechargers for everything from cell phones to personal digital assistants. Consider the hardships faced by U.S. soldiers in Iraq, many of whom lug more than 20 pounds worth of batteries to support their inventory of high-tech gear -- and might soon have to carry even more.
Small wonder that, pressured by customers, battery manufacturers including Sanyo Energy (USA), Toshiba, and a slew of U.S.-based startups have joined the Defense Advanced Research Projects Agency (DARPA) and the Energy Dept. on a quest for far smaller units with plenty more juice and staying power. At stake is a $1.22 billion rechargeable battery market, expected to grow to $1.73 billion by 2007, according to business consultancy Freedonia Group. The search ranges from finding improvements in existing batteries to developing entire new energy sources, such as fuel cells.
CHEMICAL TWEAKS. Consider how the dominant laptop battery on the market today, the lithium-ion battery, works. Think of it as a small frozen dinner container, with two compartments and a little electrode dipped into each compartment. One electrode has a positive charge, and the other electrode, made of lithium, has a negative charge. Filling both compartments is electrolyte, often a gel-like liquid allowing electrons to continuously run between the electrodes -- and provide their energy to the computer.
To keep up with the laptop's increasing power requirements, manufacturers figure they'll have to increase the battery's density -- the power it can produce per unit of weight -- by 5% to 15% annually, says Joseph Carcone, vice-president for sales and marketing at the world's largest rechargeable battery maker, Sanyo Energy (USA). That can be done by tweaking the chemistry of either of the electrodes or the electrolyte to boost the current. But that can be tricky: If not done right, it can lead to an unstable -- and explosive -- battery.
That's why scientists from Brookhaven National Laboratory in Upton, N.Y., are developing a new kind of electrolyte comprising boron and organic materials. The mix shows promise of producing a stronger energy flow and, ultimately, better battery performance. The electrolyte also prevents chemical gunk and residue from forming on the surface of the battery's positive electrode, which cuts its efficiency, says Xiao-Qing Yang, who's leading Brookhaven's Energy Dept.-funded battery research. Another benefit: It's less expensive than the electrolyte used in batteries today, says Yang.
FLEXIBLE PERFORMERS. Other companies, like electronics maker Netherlands-based Koninklijke Philips Electronics (PHG), are working on polymer-based electrolytes. Malleable and form-fitting, these electrolytes can't leak or burst, as liquid electrolytes can. Polymer batteries also don't have to be round or square. Theoretically, they can be fitted into any space and remain flexible -- and that's a major plus in handheld electronics, where space is precious.
Performance can also be improved by tweaking the electrodes' composition. Startup Sion Power in Tuscon, Ariz., has developed a battery that uses sulfur in the positive end of the electrode. The battery lasts twice as long as a typical lithium-ion device, Sion claims. A prototype, demonstrated at Microsoft's (MSFT) Windows Hardware Engineering Conference in Seattle last month, kept laptops running for up to eight hours, says Melvin Miller, Sion's president and CEO (and a serial entrepreneur who sold one of his previous businesses for $500 million). Sion is now starting pilot manufacturing and plans to begin commercial production in the second half of 2005, he says.
In Austin, battery maker Valence Technology (VLNC) is using phosphates in the positive electrolyte in its batteries. The addition makes them more stable and less prone to short-circuiting, says CEO Stephan Godevais, who previously headed a Dell (DELL) unit focused on notebook and desktop computers for consumers and small businesses. Released in February and sold at retail stores like Best Buy (BBY), Valence claims its product offers up to 10 hours of laptop power.
POWER FROM HEAT? Many believe that the traditional laptop battery will eventually be replaced with a completely different technology. Interest is high in fuel cells, which convert oxygen and hydrogen into water and, in the process, generate heat and electricity. While they're considered most promising in providing future power for cars, Toshiba expects to release in the next year a laptop powered by fuel cells. A prototype lasts 5 to 10 hours.
Still, before they enter the mainstream, fuel cells need to become more efficient and less costly to manufacture. They might find broader commercial applications in a few years, backers believe. But they'll be pressured by other alternative technologies.
Researchers at Oregon State University in Corvallis, Ore., are exploring how to generate electricity from heat transfer. They've developed a device -- the size of Lincoln's nose on a penny -- that's essentially two tiny tubes, one inserted within the other. When fuel within the innermost tube is ignited, the external tube catches the generated heat, and the device turns it into energy.
LESS HUNGRY. Engineering issues must still be overcome, such as how to keep the heat in check. But this device could create a battery that's seven times more powerful than today's, says Kevin Drost, co-director of researcher Microproducts Breakthrough Institute.
Increasing the staying power of batteries also will depend on making better power-management chips -- which moderate the laptop's power thirst. And displays, which suck up more than half of an average laptop's battery, have to start using less power, says Partha Ranganathan, senior research scientist at computer maker Hewlett-Packard's (HPQ) Research Labs.
HP, for one, has designed special power-management software that, instead of putting the laptop to sleep during periods of inactivity, lowers the intensity of the colors on the screen or makes unused parts of the display look dimmer. This can slice battery drain by 30% to 95%, depending on the applications being used, Ranganathan says.
As computing devices get smarter and offer more features, battery makers will have no choice but to experiment and innovate. They'll need all the power they can muster. By Olga Kharif in Portland, Ore.