NEW YORK-Imagine a bell curve for a clear picture of the landscape this year for batteries used in wireless handsets.
That big bulge in the middle represents the domain of rechargeable nickel cadmium and nickel metal hydride batteries, which seem likely to retain their dominant positions as primary power sources for the next year or two.
Over in the flattened left hand corner, on the lowest-cost side of the battery spectrum, are disposable, single-use Alkalines. Their mirror image on the far right, in the premium cost sector, are rechargeable lithium ion liquid batteries.
“NiCads and nickel metal hydrides are leading the bulk of production because of price,” said Gershon Cooper, president of Ora Electronics, Chatsworth, Calif. “Lithium ions are good, but their cost is too high, although it is dropping daily. In fact, we can’t afford to buy them … without some price protection from the cell manufacturers.”
Disposable alkalines, interchangeable with more advanced batteries in many wireless handsets, offer several consumer advantages, according to Jeff Jeter, director of product management for Duracell Inc., Bethel, Conn. They are available in many more kinds of retail outlets; they can be stored for up to five years; they are less harmful to the environment than nickel cadmium batteries; and they don’t self-discharge as do their rechargeable counterparts.
Lithium ion liquid batteries are a favorite for portable computers and so-called cellular smart phones geared to high-end wireless communications customers. “Lithium ion liquid has the benefit of compact size,” said David French, manager of new business development for Varta Batteries Inc., Elmsford, N.Y. “If you have five cells inside a battery pack, with lithium ion, you’ll need just two, although each will be a bit larger.”
But, like halogen light bulbs, lithium ion liquid batteries run very hot. And there have been reported instances, now under investigation, of these batteries catching on fire, according to both Cooper and French.
Farther out on the horizon are several promising technologies. Lithium ion polymer batteries “have the opportunity to be put into very thin form factors, which is of interest to wireless handset manufacturers,” Jeter said. “Bellcore, a developer of [Lithium Ion Polymer], has licensed the technology, and we have brought it into our labs and replicated what Bellcore says it can do. We don’t see any show stoppers.”
Lithium ion polymer batteries promise improved safety over the lithium ion liquids available today, according to Cooper and French. One Canadian company now manufactures them, but hasn’t promised any delivery dates, Cooper said.
Another new battery technology-lithium metal-is being developed in Israel, Cooper said. It, too, offers improved safety characteristics compared with lithium ion liquids, but also is not yet commercially available.
There isn’t any such thing as the perfect battery, although-for now-nickel metal hydrides are close, according to French. Varta manufactures “tens of thousands of lithium ion liquids a month for Siemens,” but has a stated corporate policy that it won’t recommend lithium ion liquid batteries because lithium will never be as cost effective as nickel metal hydride, he said.
Lithium ion liquid battery packs cost about $130 to $150 wholesale compared with about $59 to $69 for nickel metal hydrides, according to French. For that premium, consumers aren’t getting much in the way of capacity or energy gains, Jeter said, nor is the recharging time for a fully discharged battery much different-about an hour. Furthermore, advanced rechargers available in the aftermarket, can speed up dramatically the recharge times necessary for NiCads and nickel metal hydrides, Cooper said.
However, lithium ion technology is less mature and so more improvements are possible in it than with older nickel cadmium or nickel metal hydride technologies, Jeter said.
Nickel cadmium batteries are considerably cheaper in terms of initial purchase price, which is often included as original equipment by manufacturers. “NiCads are zero percent healthy. Cadmium is the most extremely poisonous heavy metal,” French said. “NiCads are lower-powered and have memory problems if you don’t completely discharge them before recharging.”
Until three years ago, nickel metal hydrides couldn’t compete with NiCads, he said. However, newer generations of nickel metal hydrides offer more talk and standby times, shorter recharge times and more cycle life, that is, the ability to be recharged even if not fully discharged. “Say that a NiCad costs $1 and now a nickel metal hydride costs $1.30, but it offers 200 percent more performance,” French said.
