Energized Industry
As technologies go, batteries are pretty boring. They’ve been around for roughly two centuries, they perform a simple and unchanging function and they seem almost immune to the march of progress. Compared with the many wonders of the Information Age, they’re rather lacking in pizazz.
Yet batteries have been inching into the limelight in the last couple of years, largely because their inadequacies are getting to be a serious problem. You can’t have a useful electric car, after all, if the batteries need recharging every couple of hours. And what good is that $5,000 color laptop computer if it goes dead halfway through a transcontinental flight?
Driven by the enormous business opportunity that awaits anyone who can solve the battery problem, researchers nationwide have started to come up with some promising solutions. New classes of batteries featuring exotic materials such as lithium, zinc and advanced plastics promise to produce at least two to three times more energy than current designs while remaining competitive in weight and price. But the new designs also offer an ominous glimpse of the upper limits of the technology.
“Batteries are metal-based technologies, so we’re limited because the Periodic Table only has a finite number of metals,” said Frank Harris, vice president of marketing and sales for AER Energy Resources, a maker of advanced rechargeable batteries in Smyrna, Ga. “All those metals have been tried in some combination, and when you look it from the standpoint of safety, corrosion and weight, only a few combinations fall out as being viable.”
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All batteries create chemical reactions to produce electricity, functioning like miniature power plants. When a battery-powered device is turned on, an electrical circuit is closed and electrons flow from one electrode to the other. The battery “dies” when all the electrons have traveled from the negative electrode (cathode) to the positive electrode (anode), and the battery is recharged by reversing the flow of electrons.
The battery’s chemistry--based on the makeup of the electrodes and the material they flow through, known as electrolyte--determines the voltage, or power level. The size generally determines how long it will run.
Historians credit Italian physicist Count Alessandro Volta for developing the first practical battery in the late 1790s. (The volt, a measure of the electromotive force required to produce a unit of work, was named for him.) Since then, major breakthroughs have been sprinkled decades apart.
Lead-acid batteries, the original rechargeable batteries, were developed about 30 years ago and were widely used in devices such as early camcorders and cellular phones.
Nearly 10 years ago, nickel-cadmium became the dominant technology in rechargeable batteries, used for all manner of cordless household appliances, from toothbrushes to hand-held vacuum cleaners. In the last year, a more advanced version called nickel-metal-hydride began to show signs of surpassing nickel-cadmium.
Since then, a small number of companies have been competing to bring next-generation batteries to market. Sony Corp. is the dominant manufacturer of a new kind of battery known as lithium-ion, and brought three types of the batteries to market in 1994. But a model designed to run Apple PowerBook notebook computers was taken off the market after catching fire in two computers used by Apple employees. Still, that hasn’t scared away a few American competitors who hope to improve the technology.
Lithium-ion batteries are made from layered sheets of aluminum foil coated with cobalt oxide and copper coated with carbon materials. The sheets are rolled like a jellyroll and put inside a steel container that is filled with a liquid electrolyte containing lithium hexofluorophosphate.
Lithium-ion batteries produce the same energy as nickel-metal-hydride cells but are 40% smaller, half as heavy and better for the environment because they don’t contain toxins such as cadmium or mercury. The batteries--currently being used in laptop computers, cellular phones and camcorders--boast of the highest ratio of stored power per weight of any rechargeable battery on the market.
Bell Communications Research, the New Jersey-based research and development firm jointly owned by the seven Baby Bells, developed an advanced version of lithium batteries known as lithium-polymer in the early 1990s. These batteries are infused with a solid plastic electrolyte and are stacked instead of rolled. That means they can be produced in rectangular sheets and cut to fit any shape.
“Most of the places you put batteries are square holes,” said Ralph Brodd, vice president of marketing for Valence Technology, a company in Henderson, Nev., that has licensed Bellcore’s technology and hopes to bring a rechargeable lithium-polymer battery to market early next year. “We can use the full space that’s there, so we can cram more battery power inside.”
Lithium-ion and lithium-polymer batteries can power a notebook computer with a 386 or 486 processor for about four to seven hours, depending on the particular computer and battery. But advancements in battery life are almost immediately eaten up by more powerful computers, Brodd said.
In 1992, Valence sold Motorola on the promise of lithium-polymer batteries, and two years later the company signed up Hewlett-Packard as a customer as well. But Valence fell behind schedule and delivered only prototypes for internal testing, alienating customers and sending the company’s stock from a December 1992 high of $25.625 a share down to a low of $1.75 in March 1995.
A radically different battery technology is zinc-air, which draws oxygen from the air to power a chemical reaction.
In 1989, AER Energy Resources won an exclusive right to develop zinc-air batteries for commercial applications, bringing them to market last June. The company is currently shipping two notebook batteries.
Notebook computers powered by zinc-air batteries can run two to four times longer than nickel-metal-hydride batteries--long enough for an entire transcontinental flight. AER’s Harris says zinc-air technology needs to be juiced up to provide more energy per weight and size in order to be used for hand-held cellular phones.
Perhaps the ultimate example of the painstaking slowness of rechargeable battery development is the US Advanced Battery Consortium, a group consisting of the Big Three auto makers, utility companies and the Energy Department. The consortium was pledged more than $262 million to spend on promising technologies to power electric vehicles, but so far it has found only a little more than $200 million worth of useful projects to fund.
In the near term, USABC engineers are pinning their hopes on nickel-metal-hydride batteries--already peaking in the consumer market--to produce a viable electric car.
The consortium set a midterm goal to create a battery by the late 1990s that can produce 80 to 100 watt-hours of energy per kilogram (a measure of how much energy a battery can store), more than double the 35 to 40 watt-hours-per-kilogram produced by today’s lead-acid batteries. With more research, nickel-metal-hydride batteries could meet that goal, said Frank Schweibold, director of strategic planning for General Motors’ advanced technology vehicle platform and a spokesman for the industrywide battery group.
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The long-term goal, envisioned for early in the next century, calls for a battery that produces 200 watt-hours per kilogram. The consortium is betting on lithium batteries to meet that goal. Schweibold says it might be a stretch to get lithium-ion batteries to reach the 200 watt-hours per kilogram threshold, but lithium-polymer batteries could probably meet it.
But until that day comes, consumers will have to put up with low-power electric vehicles with low range and computers, phones and other devices that run out of juice way too fast.
After all, as Nicholas Negroponte, founder of the MIT Media Lab, wrote in his book “Being Digital”: “If the progress in battery technology developed at the same pace as integrated circuits, we would be commuting to work in cars powered by flashlight batteries.”
Karen Kaplan, a freelance writer who covers technology and careers, can be reached by e-mail at Karen .Kaplan@latimes.com
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THE TROUBLE WITH CHARGES
THE PROBLEM
Rechargeable batteries are crucial components in many of the most popular and important new electronic technologies, notably wireless telephones and lap computers. But advances in batter technology have been disappointingly slow.
HOW BATTERIES WORK
All batteries create chemical-reactions to produce electricity. When a battery-powered device is turned on, an electrical circuit is closed and the reaction proceeds. Electrons flow from the negatively charged electrode, or anode, to the positively charged electrode, or cathode. The electrons travel through an electrolyte while a separator keeps the electrodes from touching and running the reaction. The battery “dies” when all the electrons have traveled from the anode to the cathode. When a battery is recharged, the electrons flow in the opposite direction.
NEW SOLUTIONS
Standard battery designs involve heavy metals such as lead. To make batteries both lighter and more powerful, new materials must be used. Here are some of the leading candidates:
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Lithlum-ion
In these batteries, the cathode is an aluminum foil with a cobalt-oxide coating, and the anode is a thin copper sheet coated with carbon materials. The sheets are layered with a plastic separator, then rolled up like a jellyroll and put inside a steel container that is filled with a liquid electrolyte containing lithium hexofluorophosphate. Lithium-ion batteries produce the same amount of energy as nickel-metal-hydride cells, but they are 40% smaller and weigh half as much. In addition, they contain no toxins such as cadmium or mercury.
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Lithium-polymer
These batteries are similar to lithium-ion cells. The cathode contains lithium instead of cobalt. Layers of anode, separator and cathode and stacked, not rolled, and infused with a solid polymer electrolyte. The main advantage of lithium-polymer batteries is that thy can be cut to fit any shape, which is convenient for device manufacturers.
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Zinc-air
The batteries draw oxygen from air to power a chemical reaction. The cathode is carbon-based and the anode is made from zinc and the separator is coated with a potassium hydroxide electrolyte. With zinc-air batteries, laptop computers can run two to four times longer than with standard rechargeable batteries. They are also being developed for cellular phones and electric cars.
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Sources: Yankee Group, AER Energy Resources, Valence Technology.
