Chevrolet Volt Webchat Answers Battery Technology Questions
Seth Fletcher from Popular Science and GM's director of Global Battery Systems Bill Wallace hosted a webchat Sept. 23. Fletcher is the author of “Bottled Lightning: Superbatteries, Electric Cars” and the new “Lithium Economy.”
Q- Is there a Moore’s Law for the batteries? (i.e. how long does it take for the battery capacity to double for the same volume, price etc..)
A- Bill Wallace: There is no Moore's law for battery technology evolution. However, we are aggressively pursuing both energy density and cost reduction improvements in our product. In general, we see significant improvements in 3-5 years, with smaller incremental improvement sooner.
Q- Will batteries ever be able to replace the combustion engine?
A- Seth Fletcher: Tough question. I'm using rough numbers here, but to match the energy density of gasoline or diesel fuel, we need a battery that can store about 2,000 watt-hours per kilogram. (Gasoline stores 13,000 wh/kg, but only a fraction of that is usable.) Lithium-ion is theoretically limited to about 400 wh/kg. Chemistries such as lithium-sulfur and lithium-air might be able to exceed 2,000 wh/kg, and many smart scientists around the world are developing those batteries on a lab scale, but it's hard to say whether they'll scale up well enough to use in transportation.
Q- Can you talk to GM's current and future plans for end of life usage/recycling of the Volt batteries?
A- GM has a partnership with grid management supplier ABB to develop prototypes of electric storage solutions for improved grid reliability using Volt batteries after they've reached the end of their useful life in the vehicle. We recently showed an early version of the prototype at ABB's R&D facility in Raleigh, N.C., and expect to have a prototype in the field next year. We're also studying solutions that will use Volt batteries in secondary applications to store renewable energy for use on the grid.
Q- Any chance you guys will be making the batteries in America? I continually hear that East Asia has all the supporting industries so it wouldn't be economical. However, I don't understand how our vast intellectual resources could not quickly bring us back to a competitive position.
A- Seth Fletcher: David, I can't speak for GM, but I can say that I've seen a tremendous amount of activity aimed at establishing a domestic lithium-ion battery industry. Thing is, it'll take time and continued support to make it happen, and historically this country hasn't been very patient and far-sighted about this sort of thing. Most of the IP that underpins today's lithium-ion batteries were developed in the West and then effectively handed over to Asian electronics manufacturers. Now we're struggling to catch up. It won't happen overnight, and it definitely won't happen if our political system decides not to support this nascent industry long enough for it to succeed on its own.
Q- What makes the Volt battery different from other battery/gas operated vehicles?
A- Bill Wallace: The Volt battery is unique because it delivers both high power as well as high energy, helping the Volt deliver full electric driving under all conditions, unlike a traditional hybrid which must rely on its engine during high power demands. High energy density allows our compact battery to deliver an EPA-estimated 35 miles of full electric range.
Q- What advancements over say a laptop battery do the volt batteries have?
A- Bill Wallace: The primary advantage of the Volt battery is extended user life, which, compared to a typical laptop battery, lasts ten times longer. In addition, the Volt battery can also deliver the power required for rapid acceleration. Laptop batteries are only able to deliver power at a low and constant rate.
Q- Are you looking into renewable sources for new batteries? Or just looking to make Li-Ion batteries more efficient? The problem I see with Li-Ion batteries is that we must import the Lithium from Afghanistan or elsewhere. How can we avoid the looming problem of running out of Lithium?
A- Seth Fletcher: Please don't let anyone ever tell you we're going to run out of lithium. Lithium is very different from the rare earths (some of which genuinely are a problem). Lithium is cheap, abundant, easy to mine and recyclable. Most battery-grade lithium currently comes from Chile, an extremely friendly country. Then there's Argentina, Australia and Bolivia have huge reserves, but we don't need them. We won't need lithium from Afghanistan for probably 100 years. And the U.S. actually has a few very large lithium deposits -- one in particular is being developed right now by an interesting company called Western Lithium, operating in northern Nevada.