Suddenly, however, the quest for long-lasting portable power is on everyone’s mind, from blue-chip Silicon Valley venture capital firms to Japanese giants like Sony and Toshiba. And it looks like there are only two options: continued improvements in existing technology, or a major breakthrough, most likely miniature fuel cells that produce electricity using methanol as fuel.
Batteries are a very old technology–2,000 years ago, jewelers in Baghdad apparently used simple batteries to electroplate their creations with thin layers of gold or silver. The technology was reinvented early in the eighteenth century, when Alessandro Volta demonstrated the first Voltaic cell for Napoleon Bonaparte, giving us both the concept of the battery and the name of the unit by which electric potential is measured. In the 200 years since, the fundamental concept hasn’t much changed–only the materials within have evolved, growing increasingly exotic and culminating in the current power champion, lithium-ion.
But at present there’s not another new battery ingredient on the horizon that can substantially beat lithium-ion. And that’s a major problem. Moore’s Law states that the complexity of circuits doubles every 18 months, while on average battery capacity increases only 5 percent to 10 percent a year. Generally speaking, the more complex a circuit–specifically, the more transistors on a microprocessor–the more current it will draw. Now add to that the new demands of wireless computing, which uses additional power to transmit and receive, and it’s pretty clear we’re approaching a major energy crisis in the portable world.
Already laptop manufacturers use every trick they can think of to minimize power consumption–the category of “power management” chips has become a booming business for semiconductor manufacturers. These chips work behind the scenes to adjust a computer’s performance in various ways to maximize battery life.
The next step will be to build power management chips directly into batteries. These chips will actually keep track of how the battery is being used and then adjust the recharging cycle appropriately. They’ll also allow very accurate “fuel gauges”–as opposed to the current battery life estimation software on laptops, which tends to have little to do with reality. Those “smart batteries” will even keep track of their usage and let owners know exactly when they need to be replaced. Of course, those batteries will also be smart enough to tell your computer what brand of replacement battery you’ve purchased–making it more difficult for consumers to buy cheaper aftermarket batteries.
Beyond smart batteries, however, is a whole new world: the miniature fuel cell. A number of U.S. startups, along with major Japanese electronics companies, are all intent on turning the fuel cell into a replacement for batteries. Fuel cells, of course, are more commonly thought of as powering electric automobiles. But a variety of technical advances have now made smaller fuel cells feasible and while no one has yet made one small enough to match the size of a current laptop battery, they’re getting closer. Last February George W. Bush actually made a call from the White House on a cell phone powered by a miniature fuel cell–although he had to hold the phone in one hand and the fuel cell in the other.
In theory, a fuel cell could power a laptop for days on a single fueling. Most likely the fuel would be methanol, probably sold in tiny pressurized containers like the canisters used to refill cigarette lighters. But there’s a long way to go–probably the remainder of this decade–before you’ll be popping a new fuel canister into your laptop once a week. Besides the need for further miniaturization, fuel cells have some inherent quirks: for example, they start up rather slowly, which probably means that laptops will still have to have regular batteries to provide power while the fuel cell gets up to capacity.
And of course, having a flammable compound like methanol inside a laptop raises all sorts of new safety issues. Late last year the Department of Transportation ruled that methanol fuel cells could be taken aboard domestic aircraft, but there is still no international clearance for the devices. And fuel cells themselves generate considerable heat, which is never good news around delicate electronics that already tend to overheat.
With that array of problems for miniature fuel cells, it’s not surprising that some companies aren’t giving up on batteries. Electrovaya, a Canadian startup, has a lithium-ion polymer technology already on sale that lets laptops run for 8 to 16 hours; they also sell a TabletPC, less than an inch thick, that runs for 12 hours on a single charge. NASA recently licensed Electrovaya’s battery for use during space walks, and a GM-Suzuki joint venture is building a lithium-ion powered vehicle. Electrovaya’s CEO, Sankar Das Gupta, believes that ultimately lithium-ion polymers will beat fuel cells in miniaturization and energy capacity.
And indeed, flashy new technologies don’t always overtake older ones. A decade ago many technologists thought that solid-state memory chips would someday replace hard disk drives. While solid-state memory has indeed developed enormous capacity and dropped steeply in price, hard disk drives have done the same, only more so. So there may yet be some unexpected juice left in traditional battery technology–and considering what’s ahead in portable computers, we’re going to need all the volts we can get.
