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A capacitor that has much greater energy density and power per pound than electrostatic and electrolytic capacitors. Used in myriad electronic circuits as well as hybrid and electric cars, ultracapacitors are also called "supercapacitors."

With a life cycle of more than a million charges, ultracapacitors are ideal for applications that require frequent, fast charges and discharges, such as hybrid vehicles that are constantly braking and accelerating. However, since they have much less energy density than storage batteries, they do not serve as a long-term energy source.

Ultra Thin Separation Layer
The separation area between the positive and negative electrodes was reduced from millimeters in electrostatic capacitors to microns in electrolytic capacitors to nanometers in ultracapacitors. Thus, the ratio of surface area to separation layer in ultracapacitors is orders of magnitude greater than its predecessors. See capacitor.

A Hybrid Vehicle Application
Maxwell's BOOSTCAP (top image) is a soda can-sized ultracapacitor used in multiples. The size of a coffee table, the 390 volt hybrid bus module (bottom image) holds 144 BOOSTCAP ultracaps that are charged when the bus is braked and discharged when it accelerates. (Image courtesy of Maxwell Technologies, www.maxwell.com)

D-Cell Sized Ultracaps
This Maxwell BOOSTCAP is the size of a flashlight D-Cell. With pins for circuit board attachment, they are used in multiples for numerous applications such as smoothing out incoming power to telecom equipment and turning a windmill into the wind. Smaller BOOSTCAPs are used to power wireless readings from utility meters. (Image courtesy of Maxwell Technologies, www.maxwell.com)
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Maxwell's power products have the lowest equivalent series resistance (ESR) and highest efficiency available with current ultracapacitor technology.
High ultracapacitor power density provides high power during surges, and the ability to absorb high power during recharging.
com)-- Skeleton Technologies Group, the leading European developer and manufacturer of ultracapacitors, with a manufacturing unit in Bautzen, Germany and the R&D and pilot unit in Tartu, Estonia, has appointed Mr.
Chief Executive Officer, FlexGen Power Systems, Josh Prueher, added : "We evaluated a number of suppliers in the ultracapacitor market and Ioxus' performance, reliability and cost are unmatched.
Ultracapacitors can also be used in conjunction with lead acid batteries to provide frequency regulation ancillary services on the grid.
We believe that this project will further validate the efficiency, low temperature performance, battery life and other advantages of combining ultracapacitor and lithium-ion technology.
This is one of dozens of high-volume industrial and transportation applications that are creating a multi-billion-dollar opportunity for ultracapacitors in the coming decade, and we continue to move aggressively to strengthen Maxwell's capabilities and global reach to capitalize on that opportunity," said Maxwell president and CEO Richard Balanson.
The secret behind the breakthrough Ultracapacitor 2.
The ultracapacitor feature allows us to better meet the demands of customers that require reliable on-site backup power in remote regions, where immoderate climates and severe temperatures negatively impact battery life spans and overall performance," said Mark Sperry, Plug Power's chief marketing officer.
ACI, which is 25-percent owned by GreenShift Corporation, noted that its ENERGel ultracapacitor electrode and electrode materials are currently available for sale, while its metal crystal composite forms are under development.
In this hybrid system, electrical energy is stored in Maxwell Technologies' Boostcap ultracapacitors that are integrated into the Hydrogenics' power pack.