By Yang-Yi Goh,TechNews
Daily Contributor 08 June 2011 10:46 PM ET
A new breed of quick-charge “liquid” batteries could help make recharging electric cars as easy as filling up at the gas pump.
Electric cars may be driving the auto industry toward a greener future, but a great number of issues still need to be resolved for them to catch up with their petroleum-guzzling forebears with regard to performance and desirability.
Perhaps the biggest problem facing electric auto designers lies in the battery: large and inefficient, today’s standard rechargeable lithium-ion batteries take hours to replenish and are suitable only for short distances. Chevy’s Volt model, for instance, takes nearly 10 hours to fully charge using an ordinary 120 volt outlet, and is able to travel only 25-50 miles before resorting to its backup gas engine.
Thanks to a group of MIT researchers, however, a new generation of leaner, more powerful, and easy-to-refuel batteries may be just around the corner. In a paper published in the May 20 edition of the journal Advanced Energy Materials, the group — led by MIT professors of material science Yet-Ming Chiang and W. Craig Carter — describe a novel approach to battery architecture that revolves around what they call a “semi-solid flow cell.”
Essentially, the new design houses the battery’s active components — the positive and negative electrodes, or cathodes and anodes — as solid particles suspended in a liquid electrolyte. This thick, quicksand-like liquid is pumped through the system during the process of charging or discharging the battery.
According to MIT, the architecture should make it possible to reduce the size and cost of a complete battery system to about “half the current levels,” while providing a “10-fold improvement in energy density over present liquid flow batteries.”
“For two decades, advances in batteries have relied on development of improved components to be used in the same basic, inefficient architecture,” Chiang told TechNewsDaily. “Our work represents the inception of ‘Batteries 2.0.’”
The batteries will hopefully bring the performance levels of electric vehicles up to par with their gas engine counterparts. Using the semi-solid flow architecture, Chiang estimates a car will be able to travel 200-300 miles on a single charge.
“Our objective is to replace ‘range anxiety’ with ‘range euphoria,’” he says. Additionally, the new design will make refueling a snap.
Drivers will have the option of either simply pumping out the liquid slurry and replacing it with a fresh batch, swapping out the tanks like you would a spare tire, or recharging the existing material when time permits.
The technology is still at an early stage of development—Chiang expects the first commercial prototypes to be ready in about two years, but foresees the semi-solid flow system challenging the current cell-module-pack approach by the end of the decade.
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