Ultracapacitor Technology Promises more Viable Electric Car


world premiere of the electric car "Audi ...

Not unlike the cell phone and laptop, the electric car has long been haunted by one question in particular: exactly how long until it's time to plug it in again? And the other big factor: cost. According to a report published today in MIT's Technology Review, however, one startup thinks it has the answer: an ultracapacitor with five to seven times the storage capacity of conventional ultracapacitors.

While ultracapacitors are generally able to deliver considerable power and can be recharged repeated without losing significant capacity, they have proven too expensive, given how much energy batteries can store for the same cost. The Nanotune ultracapacitor, however, appears to have tipped the balance, offering more storage per ultracapacitor:

[Nanotune's] ultracapacitors are close to competing with batteries in terms of energy storage, and could soon surpass them. Using a conventional electrolyte, the company has demonstrated energy storage of 20 watt-hours per kilogram, as opposed to roughly five watt-hours for a conventional ultracapacitor. Using a more expensive ionic-liquid electrolyte, it has made ultracapacitors that store 35 watt-hours per kilogram. By the end of the year, the company hopes to approximately double this storage capacity, says Nanotune CEO Kuan-Tsae Huang. At 40 watt-hours per kilogram, the ultracapacitors would be an improvement over the batteries used in some hybrid vehicles.

Now that this new technology has been discovered, the race will be to raise capacity while lowering cost. Currently, Nanotune is able to deliver energy at roughly $2,400 and $6,000 per kWh, but the company feels that costs could fall to less than $150 per kWh as it scales manufacturing and as key materials, such as electrolytes, continue to fall in price, according to the report. As a point of reference, the Department of Energy has proposed a goal of $250 per kWh to make electric cars competitive with conventional ones.

Will the electric car surpass conventional cars in popularity within five years?