Electromechanical battery

Electromechanical battery

An electromechanical battery (EMB) is a device to store energy in a flywheel,with some motor to accelerate it, and some generator to draw energy from it. [cite web|url=http://www.llnl.gov/str/pdfs/04_96.2.pdf|title=original paper|work=llnl.gov]

Figures of merit

Devices to be used as batteries are qualified through the following elements of appreciation:
* volumic stored energy (J/m³)
* efficiency of charge and discharge processes
* long term retention
* emissions (vibrations, noise, radio frequency)
* usage safety.

As of 2007, compact designs (automotive) mostly use electrochemical batteries.

Modern design

In the latest years, technological improvements gave new arguments in favor of this application of the flywheel concept.

While ball bearings or active magnetic bearings would cause a significant power leakage, a suspension with passive magnetic bearings (similar to Inductrack) is workable.By letting the flywheel spin in vacuum, energy loss only occurs by eddy currents and allows typical half-life of a few months when unused.

The passive loops can also be powered to spin up the rotor, and conversely used to draw electrical energy from the device.

Under these assumptions, you would spin the rotor at the highest possible speed before it breaks.

Issues

Two problems remain though: coping with gyroscopic effect and safety in case of rotor explosion. When the flywheel is stationary, and can be buried, it does not really matter.

In the hypothesis it would be used in a car, two contra-rotative vertical axis flywheels may cancel their effects when the car tilts back/forth or left/right, and just increases stress on the magnetic bearing.

The risk of rotor explosion at 60,000 to 200,000 RPM can be moderated by using a material that pulverises rather than creates shards at rupture. Counter-intuitively, carbon fiber is more suitable than dense metals such as lead for this purpose.

References


Wikimedia Foundation. 2010.

Игры ⚽ Нужна курсовая?

Look at other dictionaries:

  • electromechanical transducer — ▪ instrument Introduction       any type of device that either converts an electrical signal into sound waves (as in a loudspeaker) or converts a sound wave into an electrical signal (as in the microphone). Many of the transducers used in… …   Universalium

  • battery powered — Synonyms and related words: dynamoelectric, electric, electric powered, electrified, electrifying, electrochemical, electrodynamic, electrokinetic, electromechanical, electrometric, electromotive, electropneumatic, electrostatic, electrothermal,… …   Moby Thesaurus

  • Atomic battery — The terms atomic battery, nuclear battery, tritium battery and radioisotope generator are used to describe a device which uses the emissions from a radioactive isotope to generate electricity. Like nuclear reactors they generate electricity from… …   Wikipedia

  • Flywheel energy storage — NASA G2 flywheel Flywheel energy storage (FES) works by accelerating a rotor (flywheel) to a very high speed and maintaining the energy in the system as rotational energy. When energy is extracted from the system, the flywheel s rotational speed… …   Wikipedia

  • Revolutions per minute — (abbreviated rpm, RPM, r/min, or r·min−1) is a unit of frequency: the number of full rotations completed in one minute around a fixed axis. It is most commonly used as a measure of rotational speed or angular velocity of some mechanical component …   Wikipedia

  • EMB — may refer to:In organizations: *Education and Manpower Bureau a government agency in Hong Kong (also to its predecessor the Education and Manpower Branch ) *Election management body, a type of authority charged with administering an electoral… …   Wikipedia

  • Telephone exchange — A telephone operator manually connecting calls with cord pairs at a telephone switchboard. In the field of telecommunications, a telephone exchange or telephone switch is a system of electronic components that connects telephone calls. A central… …   Wikipedia

  • Electric clock — An electric clock is a clock that is powered by electricity instead of powered manually or by other sources of energy, specifically in order to wind the mainspring or to drive the pendulum or oscillator. ClassificationThere are actually four… …   Wikipedia

  • Solenoid — A solenoid is a three dimensional coil. In physics, the term solenoid refers to a loop of wire, often wrapped around a metallic core, which produces a magnetic field when an electric current is passed through it. Solenoids are important because… …   Wikipedia

  • Ship gun fire-control system — Mk 37 Director c1944 with Mk 12 (rectangular antenna) and Mk 22 orange peel Ship gun fire control systems (GFCS) enable remote and automatic targeting of guns against ships, aircraft, and shore targets, with or without the aid of radar or optical …   Wikipedia

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”