With plug-in cars now on the market, rare-earth metals are a hot commodity.

They're needed in one type of electric motor and various electronic components, and volume projections for hybrid and electric cars mean that increasingly larger quantities will be required.

China has largely cornered the market, having driven down prices earlier in the decade--it helps if there's little effective environmental or workplace oversight of your mining operations--and is now clamping down on exports.

Other rare-earth mines are planned to reopen, including one in Mountain Pass, California, but concern over reliable supplies of many different elements used in electrified vehicles permeates the industry.

So a recent press release from Ford, highlighting the reduction of rare-earth metals in its new lithium-ion hybrid battery packs seems like a welcome development.

Its older models, the outgoing Fusion Hybrid sedan and the discontinued Escape Hybrid crossover, used the same nickel-metal-hydride cell chemistry that was pioneered in the 1997 Toyota Prius and continues to this day in most hybrid models.

Ford says the company will forgo the use of up to 500,000 pounds of rare-earth metals a year, depending on production volume.

"Dysprosium, the most expensive rare earth metal used in Ford vehicles," says the release, "is reduced by approximately 50 percent" in the motors and other components of the new cars.

There's a piece of context notably missing from the release, however.

Its newest hybrids, the 2013 Ford C-Max Hybrid and upcoming 2013 Ford Fusion Hybrid, feature lithium-ion batteries not solely because they cut rare-earth metal usage, but because lithium-ion cells contain roughly twice as much energy by weight as the older cells.

That cuts the size of the battery packs by almost half, not to mention making them cheaper--as Ford notes, touting the $25,995 base price (before delivery) of the C-Max Hybrid.

But ... see that "nickel metal" piece of the older chemistry?

Nickel and other metals are used in much smaller quantities in various types of lithium-ion cells, depending on the specific chemistry used.

We're all for reducing the use of the rarest and priciest elements of auto technology.

And there's a precedent: today's catalytic converters contain only a fraction of the platinum and other metals used in 1975, when converters first appeared on production cars to reduce emissions.

But we thought we'd provide that little bit of context that Ford seems to have left out.

Just sayin'.


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