Battery Power: It’s Not Yet a “Green” World

Mobile computing won’t be mobile enough until better batteries abound

It’s no secret that the acceptance — and eventual success — of mobile computers depends on whether or not they can provide uninterrupted and reliable power in the field for hours at a time. The current crop of portable devices typically need recharging after three to four hours, clearly not enough time for mobile users. Since breakthroughs in power supply, display, and storage technologies have not yet occurred, the onus is falling once again on battery manufacturers to build more efficient power sources.

But while battery vendors are being buffeted on one side by the electronics industry and users to build more effective batteries, they are being pressured on the other by environmentalists and the government to produce “green” batteries — those that don’t pollute when disposed of or those that can easily be recycled.

The most frequently used batteries fall into two common categories — disposable alkaline and rechargeable nickel-cadmium (Ni-CD). Annually, we buy more than 2.5 billion of these “personal” batteries. The big argument for alkaline batteries is that they are convenient and inexpensive. The argument for rechargeable batteries, on the other hand, is that they can save regular battery users hundreds of dollars per year — a single rechargeable battery can replace 250 or more disposable batteries. Yet rechargeable batteries have never really caught on — the roughly 280 million Ni-CD bought in the U.S. make up only about 8 percent of U.S. personal battery sales. Why aren’t they more popular? They cost about three times as much as disposable batteries, they only last about half as long before recharging is required, and they lose power even when they aren’t being used.

From an environmental perspective, the most offensive ingredient in disposable batteries has been mercury, which is used to stabilize the formation of performance-degrading gases in the battery. (Actually lead was the first culprit, but it was removed long ago.) Perhaps the biggest problem with mercury in disposable batteries is that when they’re taken to landfills and burned, the mercury produces a dangerous ash. After intense pressure in recent years, however, mercury has been cut back so that most disposable alkaline batteries are now being marketed as “environmentally improved, 99% mercury free.” In the early ’80s, batteries were about 1 percent mercury; most of today’s batteries are about .025 percent mercury, and Duracell recently announced a completely mercury free battery with no loss of performance.

In spite of the environmental advances in disposable batteries, it would seem that rechargeable batteries are the environmentally correct choice. That’s not necessarily so. Cadmium, the heavy metal used in most rechargeable batteries, is itself highly toxic and is showing up in increasing amounts in landfills and ash.

But recycling is only a partial solution. Recycling disposable alkaline batteries has never been economically feasible so there’s no real effort in that direction. Recycling of rechargeable Ni-CD is possible and economical — France, Japan, Korea and Sweden have viable cadmium recovery programs. In the U.S., however, it is difficult to recycle rechargeable batteries because of regulatory issues — cadmium has been designated by the EPA as a hazardous waste. Still, two Ni-CD manufacturers — Gates and Sanyo — have programs that encourage customers to mail in batteries for recycling. In addition, several states, including Connecticut, New York, and Vermont, will in 1993 have laws that ban the sale of cordless appliances with rechargeable batteries that can’t be removed for recycling.

It doesn’t seem like mobile computer vendors will be able to rely upon existing battery technology to solve their power woes. New technologies are being investigated, particularly nickel-metal hydride (Ni-MH), which we covered in our February 1992 issue. However, Ni-MH batteries are also expensive. A typical AA Ni-MH sells for $8 and C cells go for $16. One drawback of this technology is that currently it cannot recharge as quickly as Ni-CD, nor can it be used with today’s chargers. Still they can store more energy than Ni-CD, making them more appropriate for mobile computers. Gates Energy Products (Gainesville, FL), a company that only manufacturers rechargeable batteries under private label for companies like Radio Shack, plans to cease production of Ni-CD rechargeable batteries, replacing them with Ni-MH batteries within the next two or three years.

Until breakthroughs come about in the battery industry, it looks like mobile computer manufacturers are going to have to focus on solving their own problems. The 3.3 volt power initiative discussed in this issue is one step.