Browse Definitions:
Definition

ultracapacitor

An ultracapacitor, also called a supercapacitor, is an electrical component capable of holding hundreds of times more electrical charge quantity than a standard capacitor. This characteristic makes ultracapacitors useful in devices that require relatively little current and low voltage. In some situations, an ultracapacitor can take the place of a rechargeable low-voltage electrochemical battery.

An excellent example of the use of an ultracapacitor can be found in so-called electrical smart meters. These devices, unlike their electromechanical counterparts, store information about home and business electrical power and energy consumption, and contain no moving parts. In the event of a power failure, an ultracapacitor allows the meter to send a final status communication to the utility company, preventing data loss and the confusion that could result. While a rechargeable backup battery can serve the same purpose, most electrochemical batteries fail at extremely low temperatures, such as commonly occur in the winter in much of the United States and virtually all of Canada. Ultracapacitors keep working at temperatures far below freezing.

Ultracapacitors can be found in emergency radios and flashlights. The ultracapacitor charges up with the help of a miniature direct-current (DC) generator that the user can manually operate for a couple of minutes by turning a small crank. Once the ultracapacitor has acquired a full charge, the device can function for quite awhile (in some cases over an hour) before it needs a recharge.

A conventional capacitor contains two electrically conductive surfaces, separated by an insulating layer called a dielectric. In general, the capacitance increases as the surface area of the conductors increases. The capacitance also goes up as the spacing between the surfaces decreases, and as the dielectric constant of the intervening insulator increases. However, a practical limit exists as to the capacitance obtainable with this design. An ultracapacitor differs fundamentally in its internal structure. Instead of having two electrodes separated by an insulating layer, an ultracapacitor employs a porous medium that produces the effect of a pair of plates with gigantic surface area, separated by only a few nanometers. As a result, the ultracapacitor has far more capacitance than any conventional high-capacitance component (such as an electrolytic or tantalum capacitor).

The principal disadvantage of the ultracapacitor, compared with older capacitor designs, is the fact that the ultracapacitor cannot withstand high voltage. While an electrolytic capacitor might be rated at several hundred DC volts, ultracapacitors have maximum ratings of only about 5 DC volts. In order to use ultracapacitors at higher voltages, multiple components must be connected in series (end-to-end, like the links in a chain). Then their voltage ratings add up, just as battery voltages add in a series connection. However, when multiple capacitors of any type are connected in series, special precautions are essential in order to equalize the voltages across the individual components. Otherwise, one of them might "hog" more than its share of the voltage and burn out as a result.

 

Continue reading about ultracapacitors:

Gigacom discusses the theory, advantages, and limitations of ultracapacitors.

Technology Review looks at emerging ultracapacitor technologies.

Ultracapacitors may someday allow wind farms to supply energy even when the wind fails to blow.

This was last updated in March 2012

Join the conversation

1 comment

Send me notifications when other members comment.

By submitting you agree to receive email from TechTarget and its partners. If you reside outside of the United States, you consent to having your personal data transferred to and processed in the United States. Privacy

Please create a username to comment.

Hi,
I am currently working on a project where I am using the battery and super(ultra)capacitors as a hybrid energy storage system for a PV inverter system. I just need help in coming up with the rating of the supercapacitor that I would use? I know that I'm gonna have to connect many in series in order to attain the voltage of ~120V but what about the C ?
Thank you so much for your time.
Cancel

-ADS BY GOOGLE

File Extensions and File Formats

Powered by:

SearchCompliance

SearchSecurity

  • copyright

    Copyright is a legal term describing ownership of control of the rights to the use and distribution of certain works of creative ...

  • keylogger (keystroke logger or system monitor)

    A keylogger, sometimes called a keystroke logger or system monitor, is a type of surveillance technology used to monitor and ...

  • password

    A password is an unspaced sequence of characters used to determine that a computer user requesting access to a computer system is...

SearchHealthIT

SearchDisasterRecovery

  • call tree

    A call tree -- sometimes referred to as a phone tree -- is a telecommunications chain for notifying specific individuals of an ...

  • mass notification system (MNS)

    A mass notification system is a platform that sends one-way messages to inform employees and the public of an emergency.

  • disaster recovery as a service (DRaaS)

    One approach to a strong disaster recovery plan is DRaaS, where companies offload data replication and restoration ...

SearchStorage

  • RAID (redundant array of independent disks)

    RAID (redundant array of independent disks) is a way of storing the same data in different places on multiple hard disks to ...

  • data migration

    Data migration is the process of transferring data between data storage systems, data formats or computer systems.

  • compact disc (CD)

    A compact disc is a portable storage medium that can be used for recording, storing and playing back audio, video and other data ...

SearchSolidStateStorage

  • SSD RAID (solid-state drive RAID)

    SSD RAID (solid-state drive RAID) is a methodology commonly used to protect data by distributing redundant data blocks across ...

  • Tier 0

    Tier 0 (tier zero) is a level of data storage that is faster, and perhaps more expensive, than any other level in the storage ...

  • PCIe SSD (PCIe solid-state drive)

    A PCIe SSD (PCIe solid-state drive) is a high-speed expansion card that attaches a computer to its peripherals.

SearchCloudStorage

  • RESTful API

    A RESTful application program interface breaks down a transaction to create a series of small modules, each of which addresses an...

  • cloud storage infrastructure

    Cloud storage infrastructure is the hardware and software framework that supports the computing requirements of a private or ...

  • Zadara VPSA and ZIOS

    Zadara Storage provides block, file or object storage with varying levels of compute and capacity through its ZIOS and VPSA ...

Close