Lithium-Ion Batteries Could be Too Expensive, MIT Team Says

By all appearances, battery-powered cars are ready for prime time. The list of companies planning to introduce new plug-in hybrids and electric battery cars in the next few years is long, and includes General Motors (the Volt and a separate plug-in hybrid), Ford, Toyota, Nissan, Chrysler, Infiniti, Aptera, Tesla (the Model S sedan), Fisker (the Karma plug-in hybrid), BMW, Bright (a plug-in hybrid commercial van), Coda, Wheego and many more.

Almost all of those vehicles will be powered by lithium-ion batteries, because lithium has the best available energy density while being very low weight. But a team at MIT’s department of materials science and engineering, headed by Donald Sadoway, is convinced that lithium is problematic for a number of reasons and is unlikely to carry EVs the extra mile to widespread consumer acceptance.

According to Luis A. Ortiz, research director of MIT’s Group Sadoway, “It’s all about the time frame. There is plenty of lithium overall [mostly in China and South America], but in order to meet expansion targets we’d have to considerably expand the pace of mining, and I don’t see ramp rates that would allow the mines to keep up with that demand. Maybe 10 to 15 years from now.”

Another huge issue is lithium cost, Ortiz said. “There is no open market in lithium, and there are very high swings in demand,” he said. The U.S. Advanced Battery Consortium (USABC) sees as its goal to “continue development of high-power battery technologies to reduce cost to $20 per kilowatt-hour and extend life to 15 years.” Such cost and lifecycle metrics would make mass penetration of battery cars a virtually foregone conclusion. But Ortiz sees $20 a kilowatt-hour as far in the future.

“The cost has to come down to the point where EVs can reach the majority of the population, and I see lithium challenges as keeping batteries at least 2X from the price USABC would allow mass adoption,” Ortiz said. He added that the high cost of containment structures (to ensure safety) and the volatile organic carbonate used as an electrolyte are “fixed overheards” that are hard to bring down over time, and very difficult to reach $100 to $150 a kilowatt-hour. Right now, Ortiz said an optimistic assessment would put lithium-ion battery technology at $400 to $600 per kilowatt-hour.

These factors will not inhibit the spread of plug-in hybrid vehicles, Ortiz said, because they use much smaller battery packs than full electrics. A recent University of Michigan survey of state residents shows widespread interest in buying plug-in hybrids: 46 percent said they might buy one if the price was $2,500 more than a traditional vehicle. If it was $5,000 more, 30 percent said they would consider such a purchase.

Ortiz’ team is working on so-called “transition metals,” a class that includes iron, titanium, chrome and manganese, because they are easily mined, and widespread so they avoid “secluded resource” issues.
Professor Sadoway said to me last February, “Sure, we can build a lithium-ion battery with 200-mile range,” Sadoway said, “but to be able to manufacture it at the General Motors or Chrysler price points is the problem. The whole system has to be crashworthy, which adds enormous costs to the enterprise.”

Here’s Professor Sadoway on video talking to a class about battery challenges:

Sadoway also said, “Instead of looking for the most powerful chemistry, and then secondarily thinking about the cost, I’m turning the problem around and saying, ‘Let’s build a battery based on elements that are earth-abundant and widely available here in the United States.’ The costs will be much lower, and that means batteries could end up so cheap people won’t mind buying new ones every three years.”