NEW YORK-Nickel cadmium batteries, long the mainstay of rechargeable power sources for wireless phones, are fading fast into handset history.
Today, nickel metal hydride batteries are emerging at the top of the charts, but this ranking may not last too long. Lithium ion technology, a relative newcomer, is fast making inroads onto NiMH’s turf. Its young cousin, lithium polymer, is still in the testing stages. However, it promises quantum leaps in desirable characteristics that likely will make it dominant if all the kinks are worked out.
Disposable alkalines remain a niche product good for emergency use. Rechargeable alkalines are preparing for their commercial arrival, but whether they will be welcomed with open arms remains a question.
Fuel cell technology, which runs rockets, might someday prove to be the end-all and be-all as a power source for wireless devices. However, right now, it remains in a realm akin to science fiction.
NiCad vs. NiMH
“A few years ago NiCads were dominant, but this year 63 percent of our phones were shipped with nickel metal hydrides, 3 percent with lithium ions and 34 percent with NiCads. In the aftermarket, we’ve just about stopped carrying NiCads,” said Al Watts, marketing manager of wireless accessories for BellSouth Cellular Corp., Atlanta.
“They’re an environmental problem, so we have an extensive collection (and recycling) program for them. In the last few years, carriers and phone makers have become a lot more aware of the environmental issue.”
Concerns about cadmium’s high degree of toxicity caused George Schmitt, president of Omnipoint Communications Services Inc., to ban their use altogether from the outset, said Lawrence Talbot, subscriber equipment manager for the personal communications services carrier.
Omnipoint, based in Cedar Knolls, N.J., began commercial service in its first market, the New York City metropolitan area, a few years ago. Its top-selling phones are sold with NiMH batteries, which cost slightly more than NiCads, Talbot said.
“We don’t even talk about NiCads anymore. We have some left, but we quit buying them in the middle of [this] year,” said Chris Turner, program manager of research and development for advanced batteries at Ericsson Inc., Research Triangle Park, N.C.
“You’ll get an argument from the NiCad makers that almost everything in a NiCad battery can be recycled, but actual recycling rates are generally pretty low,” added Turner.
Because they are comparatively “green from an environmental standpoint,” nickel metal hydride batteries don’t have to be recycled, said Dan Smith, new business development manager for the worldwide accessory group of Motorola Inc., Libertyville, Ill.
NiMH and other newer battery technologies have benefited from research into nickel cadmium batteries, he said. Although NiCad technology also continues to improve, NiMH batteries offer at least 30 percent more energy capacity for the same weight compared with NiCads.
For Motorola and Nokia Mobile Phones, nickel metal hydrides have become the most-used batteries.
“Nickel metal hydrides are our main seller, the most prevalent standard, but NiCads are good for low-end phones,” said Keith Nowak, accessories product manager for Nokia Mobile Phones, Irving, Texas.
Lithium ion
“I suspect, but I don’t know when, that lithium ion batteries eventually will become more popular than nickel metal hydrides as prices drop because they are lighter and have more capacity for the same size,” Watts said.
This battery technology has been commercially available only for the past few years, starting with just a single manufacturer, Nowak said.
Today, there are at least a dozen companies ready or gearing up to produce lithium ion batteries, according to Turner.
One of the biggest advantages of LiOn batteries is that they hold a charge a lot longer than either NiCads or NiMH cells, Nowak and Smith said.
Lithium ion batteries with a liquid electrolyte are standard in Omnipoint’s second-best selling phones, Talbot said. Besides its other advantages, LiOn permits greater flexibility than earlier technologies in shaping the battery to fit the phone.
However, Talbot and Watts noted that LiOn batteries, while environmentally safer than NiCads, also pose a possible safety hazard if they are over-charged or charged in a charger meant for other battery technologies. Consequently, manufacturers shape LiOn batteries so they cannot be used in the wrong chargers. Additionally, original equipment manufacturers implant a chip inside these batteries to prevent them from over-charging, Watts said.
“The chip is key for us. In the aftermarket world, you have to be careful because you don’t always know how [the batteries] have been inspected,” said Watts of BellSouth Cellular.
Qualcomm Inc., San Diego, uses only LiOn batteries in its phones, said Joanne S. Coleman, subscriber products marketing manager.
Nokia offers LiOn and ultra-extended LiOn batteries in its high-end handsets, Nowak said.
“Over the next one-to-two years, lithium ion batteries will be in the majority of new phones,” Motorola’s Smith said.
Ericsson expects to have some phone models available using LiOn batteries in the second half of 1999, Turner said. “We still will use NiMH in existing phones and on some of the new platforms coming out for lower-end consumers, with some option to buy lithium ion as an upgrade,” he added.
“It doesn’t cost consumers three times as much to buy a lithium ion battery, but it is three times as costly to use LiOn when you factor in the special safety circuitry you put in at the factory to protect against over-heating, over-charging and, to some extent, self-discharge.”
Lithium polymer
“As a carrier, we can’t wait for [lithium polymer] to happen. It’s an awesome thing to think about,” Watts said.
“It’s environmentally safe. You can’t over-charge it or cause an explosion hazard. It’s durable. You can drop it, throw it against a wall. It has a lot more capacity for the size. Being able to mold it would be a big advantage.”
Nowak of Nokia agreed. Lithium polymer promises handset makers the possibility of placing the “battery like a face plate on the back of the phone.”
There are perhaps a dozen manufacturers racing to get out of the box with a commercial lithium polymer product, Watts said. However, there have been setbacks so far with respect to qualities like energy capacity and useful life.
“Lithium polymer is a technology not yet realized, so anything I say is speculative,” said Omnipoint’s Talbot. “But it’s likely (if proven) to take over the entire market eventually because the manufacturing techniques are so efficient it can compete with any technology. In the lab, it’s supposed to provide 1.2 (times) to 1.5 times the power capacity of a standard lithium ion.”
The idea behind lithium polymer development is to manufacture and store indefinitely separate sheets of polymer and electrolyte. As demand warrants, these can be combined quickly into battery cells, Talbot said.
“It will allow more active material in thinner applications,” said Ericsson’s Turner, adding he believes lithium polymer technology will be commercialized next year.
Qualcomm also is evaluating lithium polymer’s possibilities, Coleman said.
“What you’ll see over the next five to 10 years are continuous improvements in variations of lithium-lithium ion, lithium polymer, solid-state lithium,” said Motorola’s Smith.
“All of the (battery) manufacturers are pouring all of their R&D dollars into making lithium perfect.”
Alkalines: Disposable, Rechargeable
“Disposable batteries are good, but you would go broke replacing them unless you work for Eveready or Duracell and can get them free,” Smith said.
To use disposable batteries in a wireless phone would cost more than $100 a year, said Talbot of Omnipoint.
Because they come out of the package fully charged and ho
ld their charge for a very long time, disposables fill a useful niche: for consumers who keep a wireless phone only for emergency use; for those who need to use their handset immediately when its reusable battery needs a charge; and for travelers in foreign countries who want to avoid carrying a special adapter for their battery charger.
Since manufacturers of disposable alkalines removed mercury from their batteries several years ago, they no longer contain a highly toxic metal. Nevertheless, Ericsson’s policy is to discourage the use of disposable batteries because they add to the household trash waste stream, Turner said.
“Rechargeable alkaline technology isn’t ready yet. We haven’t decided within Ericsson if we want to use it or not. To be honest, I have a negative feeling,” he said.
For Omnipoint’s Talbot, the discouraging issues around rechargeable alkalines come down to the battle for shelf space and the need for consumer education-not whether these batteries work well for their cost.
Rechargeable alkalines are the opposite of NiCads in one key characteristic. Because of the so-called memory effect of NiCads, especially earlier generations, people who had frequent but short wireless phone conversations found their NiCads lost full rechargeability capacity over time.
Rechargeable alkalines, on the other hand, work great under the very conditions that are bad for NiCads. However, they must always be replaced in the charger after each use in order to maintain their staying power.
“The benefits are they arrive fully charged, have long talk times comparable to lithium ions, can be recharged many times and are less expensive than LiOn or NiMH,” Talbot said.
“We haven’t released any consumer handsets with rechargeable alkalines. They require a change in consumer habits, good for those with very structured usage patterns.”
Fuel cells
“I’ve read about the basics behind fuel cell technology. It gives you phenomenal energy. If they are able to mass produce it, it would be revolutionary. That’s a big `if’,” Talbot said.
Talbot said his time horizon is three years. Over the next year, lithium ion prices will get down to the level of nickel metal hydrides. Within three years, lithium polymer will become commercially available in quantity.
However, the same strong demand for ever-more-powerful batteries that is driving lithium technologies also may cause fuel cells to come to market sooner than anyone expects, Talbot said.
“Fuel cells are a very difficult proposition to bring down in size, but they have possibilities-very high risk but very high reward,” said Turner of Ericsson.
Saying he wouldn’t dismiss as quacks scientists working on fuel cell technology for wireless devices, Turner added that he believes this technology could begin to show commercial promise within five years.
Smith of Motorola and Coleman of Qualcomm said their companies are keeping their eyes peeled for all potentially promising battery technologies.
