Ultracapacitors look to fit into energy storage

Judged by media buzz and venture capital dollars, lithium ion batteries are the name of the game in the emerging field of storage for electric vehicles and the power grid. But there is a cadre of companies pursuing ultracapacitors that can work hand in hand with batteries.

South Korea-based Neescap on Tuesday said that it has raised $9 million in bridge financing to expand production of its ultracapacitors for the transportation, power industry, and consumer electronics markets.

Ultracapacitors: an alternative route to energy storage than batteries.

(Credit: Ioxus)

In the U.S., early-stage companies designing the materials and electrolytes for ultracapacitors include Graphene Energy, EnerG2, and Ioxus. Much hyped EEStor, backed by venture capital firm Kleiner Perkins Caufield & Byers, has signed a supply deal with electric vehicle company Zenn, although its products are still not commercially available.

Compared to batteries, ultracapacitors can't store a lot of energy, so they wouldn't typically be used alone to run plug-in electric vehicles. On the other hand, ultracapacitors are "power dense," which means that they can discharge the energy they do have quickly. Conversely, they can be recharged quickly--in seconds or minutes, and with almost no degradation in performance over time, say backers.

Ultracapacitors are already used in consumer electronics such as digital cameras to help provide a burst of power for flashes, which extends overall run time, said Chad Hall, the chief operating officer of Oneonta, N.Y.-based Ioxus, on Tuesday. The technical challenge for ultracapacitor companies in the coming years is to build storage devices that can operate in high-voltage applications, he said.

Ioxus, which means "power" in Greek, was spun off from its parent company three years ago to pursue energy storage in electric transportation, renewable energy storage, and backup power. Rather than replace batteries, the company expects that its ultracapacitors, which it began manufacturing earlier this year, will complement them. "It all comes down to hybridization. We've got hybrid cars, so you need to hybridize energy storage," he said.

One of the first markets the company is pursuing is fork lifts. An ultracapacitor could be used for the jolts of power needed to lift heavy things, which would give a longer life to fork lifts' lead acid batteries, said Hall. Other promising uses include maintaining the stability of grid frequency, he said.

"Ultracapacitors enable battery technology, or fuel cells, or solar and wind. They become the bridge you need for most of those applications to go forward. It's gotten to the point technology-wise so that you can do that," he said.

Another advantage is that Ioxus ultracapacitors don't use hazardous materials. But getting the price low enough for these applications remains a barrier, he said.

Breakthroughs ahead?
Joel Schindall, a professor of electrical engineering and computer science at Massachusetts Institute of Technology, predicts that ultracapacitors will make a jump in energy storage capacity in the years ahead.

Right now, ultracapacitors discharge 10 times faster than batteries but only store about 5 percent of the energy as comparably sized batteries, Schindall said last Wednesday at the EmTech emerging technology conference.

"It's still useful in applications when you charge and discharge frequently, such as regenerative braking, but it's not a replacement for batteries at a large scale," he said.

For the past five years, Schindall has been leading research on ways to replace activated carbon--the porous material in ultracapacitors that stores electric charge--with a "shag carpet" of carbon nanotubes on a conducting substrate. The company FastCap Systems was formed earlier this year to commercialize the technology.

Schindall projects that ultracapacitors eventually will be able to store as much as 25 percent of the energy of batteries, a jump he said would be "disruptive." Right now, nanostructures developed by MIT researchers can hold twice as much energy as activated carbon. In the coming months, his team expects to show it can hold five times the energy as activated carbon, he said.

[Philips]

"On the other hand, ultracapacitors are "power dense," which means that they can discharge the energy they do have quickly."

And capacitors usually leak power rather "quickly" too...

Wow! Man, you just single-handedly defeated MIT professors! What were they thinking?! Useful? Boy, were they wasting their time! You should call them!!

[holyhope]

No these modern capacitors hold better than ni-cad. I have one of those shake $5.00 flashlights, and it keeps the charge better than batteries. Months later you can just use it, not like the $31.00 flashlight I got 8 years ago.

[phoebus1--2008]

Can ultra-capacitors be used to fire high energy thermal lasers? Thinking here of a recessed cupola under an aircraft nose (plus one above the cockpit) and a thermal laser being used for airborne and on-the-ground anti- (or de-) icing of wing and tail leading edges..... and forward surfaces.

When icing conditions don't require de-icing, the cupola housing the laser GUN could face forward and zap any detected birds a few hundred metres away along the flight-path (who then typically and instinctively quickly peel off and dive out of the way).

[phoebus1--2008]

Of course any de-icing would be directed at excrescences that are either pre-mapped or detected, in a preliminary fashion by a profile mapping laser.

For the anti-birdstrike application, the LIDAR (bird detecting radar) would utilize the same profiling laser in a different mode.

[man_w_balls]

Toyota demonstrated a hybrid racecar in 2007, the Supra HV-R, which used "quick-charging capacitors" instead of the normal Li-ion batteries for its electric motors. It made 19 more laps than every other car in the 24-hour race.
The way that racing uses high amounts of acceleration and braking made the switch to capacitors more sensible, since they are recharged quickly by the regenerative braking and discharged in Supra-boosts.

[Hernys]

LiFePo batteries have very high charge and discharge currents, last millions of charges and have no problems with deep discharges or full charges. They are less dense than Lithium Cobalt batteries, but way more dense than ultracapacitors, even with the 5x improvement. So the ultracapacitors would have to offer at least an additional 2x improvement in capacity (and a significant reducion in costs) to have any value in vehicles, assuming chemical batteries do not improve at all in the mean time.

[texaslabrat]

millions of charges? Erm, no. The manufacturers themselves speak of charge cycles of 1-2 thousand before capacity losses occur. Granted, the capacity loss rate is pretty slow as lithium-based batteries go..but "millions" is a gross exaggeration.

At the end of the day, neither straight-up battery packs nor straight-up ultracapacitors is likely to be the best possible solution since each has specific strengths and weaknesses. A combination of the two makes for the most optimal power storage and discharge architecture

[gregalexander19]

A great website on ultracapacitors is here: www.ultracapacitors.org. I can see soon that they will merge the capacitor with the battery for a new super battery. I am glad to see this technology starting to get more press.

[USDecliningDollar]

At one time, EEStor received money from Kleiner Perkins - the KP site no longer mentions EEStor, with the exception of a single PDF which states that they invested $x 3 -4 years ago in EEStor.

Zenn is no longer in the business of being a vehicle supply company, they are now working on the "Zennergy Drivetrain" - which if you press Zenn for details, doesn't exist yet. The Zennergy Drivetrain, which doesn't yet exist will work with the years behind schedule, yet unseen by the public; based on physics which sounds like BS - EESU. Which seems to be a match made in heaven - ethereal drivetrain matched with ethereal battery - perfection.