What’s wrong with good old C, D and double-A batteries? It’s the technology: two chemicals known as electrodes, with different abilities of attracting electrons, undergo chemical reactions with a third substance called an electrolyte. The flow of electrons among them creates electrical current. There have been many improvements in both electrodes and electrolytes since the first voltaic battery, but the basic concept is unchanged. So is the basic problem: more power means more chemicals and thus, bigger size and more weight.
Both qualities are liabilities. The Reno, Nev.-based iGo Corp., a seller of batteries and power adapters, polled a sample of its quarter-million customers. “Seventy-eight to 80 percent of [mobile-phone] users would pick 20 percent more battery life than a 20 percent reduction in size,” says iGo CEO Ken Hawk. Laptop users, on the other hand, wanted the lightest batteries possible. Hence the holy grail of portable power sources: technology that combines high power and low weight.
The leading candidates can be decades-old, updated with semiconductor manufacturing techniques. Manhattan Scientifics, for example, is pursuing fuel cells, longer-running devices that rely on a chemical reaction between oxygen and some fuel such as hydrogen. Originally, fuel cells were huge, and the hydrogen could be dangerous. The new micro fuel cells use a safe type of alcohol. When the fuel runs out, in goes a new ampoule. The company, which will start shipping the new cells next year, hopes eventually to be able to power a mobile phone in standby mode for as long as six months on a single fueling.
Another new battery type is the lithium polymer, an improvement over the lithium-ion batteries that often run cameras and portable phones and laptops. “It’s a solid-state battery, therefore you can make very thin cells,” says Dr. Chao-Yang Wang, associate professor of mechanical engineering at Penn State University. Semiconductor technology helps keep costs low. Sheets of battery might be molded to become part of a device. The cover for a laptop, for instance, might be a lithium ion battery. “We feel the lithium ion is the technology of the future for most of our applications,” says Dr. Khushrow Press, president of Saft America, a division of France’s Alcatel and a major battery supplier for aerospace, transportation and military uses.
Not all new approaches are children of Silicon Valley. Power Paper Ltd. of Tel Aviv uses commercial printing presses to literally print batteries. “Until [now],” says CEO Baruch Levanon, “all batteries need to be sealed in some kind of metal case.” At about one fiftieth of an inch thick, the resulting cells are flexible and can be produced in any shape, making them ideal for disposable electronics, such as talking gift cards or single-use medical sensors. According to Levanon, “environmentally friendly materials” makes them safe to throw away.
Then there are chemistry combinations being moved into new uses. Zinc air, once the province of hearing aids, has been available for the last half year in emergency backup batteries for mobile phones. Evercel, Inc., in Danbury, Conn., has taken another chemistry, nickel zinc, and improved the recharging ability to power scooters that travel about 25 miles an hour.
There are problems that must be addressed. The more powerful the battery, the more potentially dangerous, making safety features a must. It is also expensive to bring a new battery to market and difficult to obtain customer acceptance. “Many technologies have been ‘sexy’ at a particular time and five years later dropped,” says Press.
And then there are products that Hawk calls just plain “crazy,” like the external battery whose maker said it would run a laptop for 12 hours. “But it weighed close to 25 pounds,” Hawk says. “It’s not a good bang for the buck.” Sometimes, it seems, you can actually make a mousetrap worse.
