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Advancing Materials

Although the technology that is powering your notebook computer and the coating that may be on the CD that you picked up over the weekend are both potentially from Energy Conversion Devices, this Troy, Michigan-based firm may give a whole new meaning to "gas tank."

 

"Think of us as a materials company," he counsels, which is difficult to do. After all, a materials company is one that, generally speaking, makes coils of steel or tons of resin or the like. But maybe the thing is that steel and plastic and the like can be considered as "Old Economy" materials, and when Robert C. Stempel, chairman of Energy Conversion Devices (ECD; Troy, MI)—yes, the Robert C. Stempel who was president, then chairman, of General Motors circa 1987-1992—talks about noncrystalline, amorphous, and thin-film materials—materials that do their work at a thickness of a micron or less—he is talking about New Economy materials.

A specific example supporting this conjecture is found in the material that is at the heart of a joint venture company formed by ECD and Tyler Lowrey, former chief technology officer of Micron Technology, a leading semiconductor memory firm. Speaking of what Ovonyx, the new company, is about, Stempel explains that they're developing a propriety phase-change technology that can be used to make nonvolatile memory for semiconductors. Instead of optically reading information (or phase changes), this new material will permit it to be done electronically. "We can do it very fast and at low voltage," he says. As for the non-volatile characteristic: "Shut your power off on your computer, and you still have all the data. And it can provide instant start when you turn it on." In other words, none of those seemingly endless boot-ups when you turn your computer on.

Stempel has all sorts of other examples of materials that ECD has developed and is developing. They have a thin, flexible photovoltaic material that may not be as efficient as the crystalline material (gallium arsenide) that is ordinarily used to generate electricity from sunlight but which is light and ages well; Stempel points out that panels of this material are being used by the Russian space station Mir—and that while the space station may be falling apart, the photovoltaic material, which has been up there since November 1998, is doing its job.

Semiconductor memories and clever ways to turn sunlight into power (there are plenty of down-to-earth applications for the photovoltaics: Stempel proffers a roofing shingle made with the ECD process: you can drive roofing nails through it and it still works) are certainly interesting things, but fundamentally, Stempel is a car guy.

Ovonic Battery Co. is a subsidiary of ECD; it was founded in 1982. Ovonic has been producing nickel metal-hydride (NiMH) batteries since the late 1980s. Stempel recalls, "I came here looking for batteries for electric vehicles. I did sort of a due diligence; I looked at a lot of batteries. I liked this one because it is pretty understandable and straightforward. You can tailor the material with different alloys—move this battery from high-energy, which gives you a lot of range, to high power, which gives you a lot of acceleration. That's good when you're working with an electric or hybrid car."

In 1994 General Motors and Ovonic Battery formed a manufacturing joint venture, GM Ovonic, which produces NiMH batteries for electric vehicles—like the EV1. The EV1 is on the second-generation NiMH pack: "People in California," Stempel says, "who have the EV1 routinely report they're getting 140 to 160 miles per charge. That meets most daily driving needs."

Although electric vehicles have gotten a bad rap (mainly from internal combustion engine-oriented journalists), Stempel admits, "I happen to like pure electric cars, so I am biased." He points out, "One thing that we did with the electric car that I'd like to be able to redo is to tell people how to use them.

"We told people what the shortcomings were. We told them that they had to be sure to plug them in at night so that they'd be charged in the morning; we said that it doesn't go too far; we said that their electric bill would go up a bit—but didn't tell them their gasoline bill would go to zero. It was almost like we didn't want to sell them."

Stempel provides a good analogy of how something can have limitations yet be perceived as extremely viable: a lap top computer. "If I told you that you were going to have just four or five hours of run time and then it would shut down, you probably wouldn't be interested."

Stempel is pursuing other transportation-related applications for NiMH batteries, especially in Europe, for things like small motor scooters (as replacement for two-cycle gas engines) and delivery vehicles. And they are continually working on the ways and means to develop batteries that are more efficient, such as modifying the constituents of the hydride powders and trying different types of insulators (they've even tested leak-proof baby diapers).

Although much of the interest of automakers seems to be with hybrid vehicles—those combining an internal combustion engine with electric motors—Stempel points out that those who have done electric vehicle development deserve credit, pointing out that thanks to the availability of efficient electric drive and control systems, it was a comparatively easy step to the hybrid.

But there may be something of a hybrid in ECD's future, or at least ECD will facilitate the development of a fairly straight-forward hybrid, one that will be able to use the existing manufacturing infrastructure for internal combustion engines.

In other words: Think of the way engines are manufactured right now. With but a few modifications to the fuel delivery system—tweaking the compression ratio and modifying the fuel injectors, for example—an engine that's being manufactured in Romulus or Romeo or Trenton or Anna could become a comparatively clean engine. The exhaust would be water and a small amount of NOx.

This capability is to be realized through the use of hydrogen fuel, H2.

You can contain hydrogen in liquid form. But there is a slight drawback: You have to keep it cold in order to maintain it in a liquid state: at –250°C. BMW is working with liquid nitrogen.

You can store hydrogen as a gas. But in order to obtain a useful volume of the gas (as you may recall from chemistry, hydrogen is the element that starts the Period Table: it is exceedingly light), it must be maintained under pressure. At about 5,000 psi. Ford is working with pressurized hydrogen gas.

But Stempel and the crew at ECD have good experience working with hydrogen through the NiMH batteries (remember: the H stands for hydride). And as manufacturers of the thin-film materials that are used in the batteries, they have good familiarity with the means by which the materials can be modified in order to create new characteristics. Both of which have led them to what could cause a change in which hydrogen is stored for vehicles.

Ned T. Stetson, PhD., senior research scientist, Hydrogen Technology, ECD, hooks up a Sony radio/cassette recorder to a fuel cell about the size of a sleeve of saltine crackers. The connection is made with a small-gage wire. And to the fuel cell he fits a small-diameter hose that's attached to a gas cylinder about the size of a stick of pepperoni.

Stetson opens a valve on the cylinder—which contains hydrogen—so that the gas flows into the fuel cell, which transforms the gas into electrical energy. The tunes begin to play. Stetson turns the Sony around and shows that the unit isn't plugged into a wall socket and that the batteries are missing. Hydrogen is making it happen.

What they have discovered at ECD is a means by which hydrogen can be stored as a solid, in a hydride material. It goes in as H and comes out as H2. The use of magnesium in the material permits the holding of the hydrogen. Although magnesium can store lots of hydrogen, the problem is getting the hydrogen released from the magnesium. As Stempel puts it, "It can take hours to get out—which doesn't work well for an automobile." What ECD has done is to find the means by which the hydrogen can be released in a way that would permit the powering of an automobile, either via a fuel cell, or as an alternative to gasoline for the conventional internal combustion engine.

"One of the things that intrigues us with this hydrogen storage," Stempel says, "is that we can run a piston engine with hydrogen fuel. It doesn't have quite the energy of gasoline, which is a complex hydrocarbon, but when it comes to emissions, they're extremely small."

According to Stempel, the metal hydride material would be coiled up in a container that is about the size of a conventional fuel tank for a midsize car. Filled with hydrogen, the container, which would be fitted where the gas tank is ordinarily mounted, weighs about 120 kg, which is about 2 to 2.5 times more than a conventional gasoline-filled container. The hydrogen would be sufficient to power a vehicle from 300 to 350 miles.

Although some people might imagine that this is something that may happen at some point in the far-distant future, Stempel is convinced that things will happen much more quickly: within a few years, not a few decades. Underlining the potential and the reality of this is the fact that in early May, Texaco bought a 20% equity stake in ECD. According to the official release announcing the purchase agreement, "the companies"—as in Texaco and ECD—"have agreed to establish joint ventures for the continued development and commercialization of advanced energy technologies, initially in the fields of ECD's proprietary Ovonic solid hydrogen storage technology and the Ovonic regenerative fuel cell."

It may be a materials company. But the materials are certainly different than those who work in the auto industry are generally familiar with—for now, at least.

The GM Precept is a demonstration vehicle; there are fuel cell and hybrid versions. One of the versions includes two NiMH battery packs that provide 350V, 3 kW-hour usable capacity. Apparently, the GM engineers were thinking that lithium polymer batteries would be the way to go (and there is a version that does employ them) because of power density considerations. Stempel says of the NiMH batteries: "They were surprised that we could provide the same power as the lithium polymer."

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