24M, a spin-off from battery maker A123 has published a paper which describes a new type of battery that would outperform any existing lithium ion unit designed for electric vehicles. Today’s lithium batteries are bulky and heavy just because there’s a lot of extra material in them that doesn’t have anything with the storage of energy, but merely with supporting the active “ingredients.”
Only about 25 percent of the battery is thus used for energy purposes. The rest is made from metal foil current collectors and plastic film separating the layers from each other. 24M’s new battery concept is supposed reduce battery prices to $250 per kilowatt hour, which is less than half they currently cost.
Their approach uses a sludge-like material for the electrodes, instead of solid thin films. The material is stored in two tanks, one holding the positive electrode material and the other the negative. Then, the sludgy electrodes are pumped from the tanks into a small device, where they move through channels carves through blocks of metal. As this happens, ions move from one electrode to the other through the same kind of separator material used in a conventional battery.
No extra wires or insulating materials are needed, except for the electrodes. The battery capacity can be dynamically increased by adding more electrode material to the two tanks. The researchers, led by Yet-Ming Chiang, a professor of materials science at MIT, and a founder of both A123 Systems and 24M, tested various materials for the electrodes, including lithium cobalt oxide, which is commonly used in laptop batteries. They demonstrated that the device can charge and discharge at the rates needed in electric vehicles, Chiang says.
24M, with a total of 20 employees has already received $16 million in funding, and that’s the reason everybody’s optimistic about their chances of success. Although it’s far from being able to be implemented in any electric vehicle yet, the concept works in theory and the first experiments with the technology prove it. “We’re making good progress on the technology,” says 24M CEO Throop Wilder. “The acceptance of the paper is strong validation of the fundamental principles that drive our development.”