IEEE on automotive batteries

1 October 2007

Anyone interested in knowing more about the batteries that will power the coming generation of all-electric and hybrid vehicles should zip over to IEEE Spectrum: a publication from the Institute of Electrical and Electronics Engineers. In Lithium Batteries Take to the Road, journalist John Voelcker gives a great account of where batteries are today and where they are heading in the near future. A little knowledge of chemistry will aid the reader, but even those keen to skip descriptions of “lithiation and delithiation” will find the rest of the text informative and accessible.

The article focuses on cutting-edge battery supplier A123Systems, which has been signed up as a supplier by General Motors, but also mentions rival Altair Nano and electric sports car pioneer Tesla Motors.

Three paragraphs particularly leapt out...

On safety:

If a lithium-ion powered minivan carrying a family were to burst into flames, the resulting fiasco could set the industry back a decade. And it’s no use arguing that something like 250,000 gasoline-powered cars catch fire every year in the United States alone. New products are held to a higher standard.

On cell degradation over time, irrespective of charge/discharge cycles:
Cobalt-based cells for portable electronics lose as much as 20 percent of their capacity each year, starting from the day of manufacture. That may be tolerable for cellphones and other portables that are replaced every three or four years, but not for a car, which is expected to last 15 years.

And finally on cost. No wonder the Tesla is expensive:
At the moment, 12V lead-acid batteries cost US $40 to $50 per kWh. Nickel-cadmium and nickel-metal-hydride cells for portable electronics cost $350/kWh; lithium-ion cells for the same market go for $450/kWh. Move to hybrid vehicles, though, and the price for longer-lived, more rugged nickel-metal-hydride batteries shoots up to about $700/kWh.

Next » « Previous Home