Will Celmet* be the Elixir for Electric Cars?

The newly created material is called Aluminum-Celmet** and when the surface is magnified it looks like a metallic sponge.? Used to in making batteries, the material can increase the capacity of a battery by as much as 200 percent.? If that?s the case, suddenly the Nissan Leaf has a range of more than 200 miles and a Tesla Roadster more than 700 miles, and ?range anxiety? could disappear like $1 per gallon gasoline.

Developed by Sumitomo Electric Industries, Ltd., a manufacturer of optic fiber cable and electric wire, the porous metallic material has up to 98 percent porosity and it?s easy to process into various shapes by cutting and stamping.? These are very desirable traits for making the positive electrode current collector in hybrid vehicle nickel-hydrogen batteries.


Aluminum-Celmet magnified 40 times

Celmet is a porous metal made from nickel or nickel chrome alloy. The manufacturing process comprises electro conductive coating to plastic foam, followed by nickel plating and then the plastic foam removal by heat treatment.

Sumitomo has developed a similar process of making the Celmet using aluminum, which offers lightness (the specific gravity of aluminum is about one-third that of nickel) and greater electrical conductivity (or low electrical resistivity, less than half that of nickel).

In addition to sharing the high porosity feature of Celmet, Aluminum-Celmet has excellent corrosion resistance.? This makes it suitable for use in lithium-ion and other secondary batteries operating at high charge/discharge voltages, for which Celmet made from nickel is not suitable. Aluminum-Celmet can also be used for current collectors in capacitors.

Sumitomo explains the advantage like this, ?The positive electrode current collector in a conventional lithium-ion secondary battery is made from aluminum foil, while the negative electrode current collector is made from copper foil. ?Replacing the aluminum foil with Aluminum-Celmet increases the amount of positive active material per unit area. Sumitomo Electric?s trial calculations indicate that in the case of automotive onboard battery packs, such replacement will increase battery capacity 1.5 to 3 times. Alternatively, with no change in capacity, battery volume can be reduced to one-third to two-thirds. These changes afford such benefits as reduced footprint of home-use storage batteries for power generated by solar and other natural sources, as well as by fuel cells.?

In conventional capacitors, both positive and negative current collectors are made from aluminum foil. ?Use of Aluminum-Celmet instead improves the capacity and reduces the footprint, as with lithium-ion batteries.

Sumitomo Electric Industries, Ltd., having newly developed its porous aluminum ?Aluminum-Celmet,? has set up a small-scale production line at Osaka City, Japan, to accelerate development efforts toward mass production of the new material.? To date, battery manufacturers have yet to embrace the new materials, but if it is as good as it sounds, we may soon be reading about new batteries for hybrids and electric cars.

* Celmet is a trademark or registered trademark of Sumitomo Electric Industries, Ltd.

** Aluminum-Celmet is a trademark of Sumitomo Electric Industries, Ltd.

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