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‘Cambridge crude’ may charge up e-cars

By Calvin Hennick
Globe Correspondent / June 13, 2011

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Electric cars have yet to make the sort of headway their advocates hope for. The cars, hampered by expensive batteries and limited range, have not caught on with consumers. But Massachusetts Institute of Technology researchers have come up with a technology to run car batteries on something they call “Cambridge crude,’’ which they hope will allow for cheaper, longer-range electric cars by the end of the decade.

Yet-Ming Chiang, a materials science and engineering professor at MIT and leader of the research team, called the design a “semi-solid flow battery.’’ It combines elements of two current technologies known as lithium-ion (common in consumer electronics) and flow batteries, which are made with less-expensive materials.

“We take the solid compounds that are normally used in lithium-ion batteries for energy storage and turn them into a fluid suspension of particles that can be used in a flow architecture,’’ Chiang said.

That fluid suspension is a black slurry that resembles crude oil, and Chiang said it has the potential to change the way people drive. It could eventually produce batteries that provide 200 to 300 miles of driving range on a single charge, up from the 80 to 100 miles offered by existing batteries.

The new batteries are also projected to be far cheaper, potentially bringing the price of electric cars down to a level comparable to that of gasoline-operated cars.

“Our goal is to make it completely transformative and give the user no reason not to drive an electric car,’’ Chiang said.

The batteries would be rechargeable, but to save time, Chiang said, motorists could pump out the used “Cambridge crude’’ and replace it, or swap their batteries for fully charged ones at fuel stations.

Chiang has said the technology has potential applications for the electricity grid, too, because of its capacity to store renewable energy.

Solar and wind power cannot be produced 24 hours a day; batteries are necessary to store power produced during daylight hours or windy periods so it can be fed to the power grid during off hours.

The batteries would not be useful for small-scale technologies like cellphones and laptops, he said.

Jay Friedland, legislative director for Plug In America, the San Francisco electric car advocacy group, said such a system would be a Holy Grail of electric car innovation.

“The devil will be in the details in terms of what will be the infrastructure requirements,’’ Friedland said.

Consumer acceptance of cars powered with the battery technology will depend on whether enough facilities can be built to make charging or swapping out dead batteries convenient.

“Can you get the infrastructure in place to either fill the cells or swap the cells that won’t be too costly?’’ he asked. “Swapping out gasoline infrastructure is hard.’’

Chiang and MIT professor W. Craig Carter performed the initial research with a team of graduate students and post-doctoral assistants.

In May, they published their findings in the journal Advanced Energy Materials.

Chiang, Carter, and entrepreneur Throop Wilder have founded a company called 24M Technologies Inc. to develop the technology for the commercial market.

Between the work at MIT and the company, Chiang said, the research has attracted about $7 million in federal grants and $10 million in venture capital investment.

Chiang said his team expects to produce a commercial prototype within two years, but it could take several more years for the battery to be approved for use in cars.

Dan Steingart, an assistant professor of chemical engineering at City College of New York, read the team’s research paper and called it a significant advance. However, he said it would be difficult to produce batteries that can be drained and refilled without contaminating the fluid with water.

“Keeping the water out on a commercial-scale system is going to be a significant challenge,’’ Steingart said.

Wilder, the cofounder and chief executive of 24M, said that problem is solvable.

“What car makers are doing is giving you just enough battery to give you just enough range, because the batteries constitute so much of the cost,’’ Wilder said. “With our technology, you could have parity.’’