SUPERCAPACITORTechnical seminor on supercapacitor

Presented byB.Bharath kumar

13605A0401

Table of contents1.Introduction of capacitors.2.What is supercapacitors..?3.History of supercapacitors.4.How it differ from Batteries.5.Working principle of supercapacitors.6.Features of supercapacitors.7.Advantages and Disadvantages of

supercapacitors.8.Applications of supercapacitors

Introduction of capacitors.

What is Capacitor...?• A Capacitor is a passive two terminal electrical

component used to store the energy in the form of electric field.

• When there is a potential difference (voltage) across the conductors, a static electric field develops across the dielectric, causing positive charge to collect on one plate and negative charge on the other plate. Energy is stored in the form of electrostatic field.

• Capacitance is defined as the ratio of the electric charge Q on each conductor to the potential difference V between them. The SI unit of capacitance is the farad (F), which is equal to one coulomb per volt (1 C/V).

• Units of capacitor is Farad.Typical capacitance values range from about 1 pF (10−12 F) to about 1 mF (10−3 F).

capacitors

capacitors symbols

What is supercapacitors..?

• A supercapacitor or ultracapacitor is an electrochemical capacitor that has an unusually high energy density when compared to common capacitors.

• A supercapacitor (SC) (sometimes ultracapacitor, formerly electric double-layer capacitor (EDLC)) is a high-capacity electrochemical capacitor with capacitance values much higher than other capacitors.

• They typically store 10 to 100 times more energy per unit volume or mass than electrolytic capacitors.

History of supercapacitors.

• The first supercapacitor based on a double layer mechanism was developed in 1957 by General Electric using a porous carbon electrode [Becker, H.I., “Low voltage electrolytic capacitor”, U.S. Patent 2800616, 23 July 1957].

• the Standard Oil Company, Cleveland (SOHIO) in 1966 that patented a device that stored energy in the double layer interface [Rightmire, R.A., “Electrical energy storage apparatus”, U.S. Patent 3288641, 29 Nov 1966.].

Classification of Supercapacitors

How it differ from Batteries.

• Both capacitors and batteries are used to store the potential energy.The difference is capacitor stores potential energy in the form of electric field but battery stores it in chemical form.

• supercapacitor charging time is very faster than battery.supercapacitor charge time is few seconds but battery charging time is several minutes.

• cost of the supercapacitor is more than a battery.• life of the supercapacitor is more than a battery.• supercapcitor can charge and discharge at negative

temparatures also whereas battery does not charge at negative temparature

Working principle of supercapacitors.

• A supercapacitor (often called an ultracapacitor) differs from an ordinary capacitor in two important ways: its plates effectively have a much bigger area and the distance between them is much smaller, because the separator between them works in a different way to a conventional dielectric.

• In a supercapacitor, there is no dielectric as such. Instead, both plates are soaked in an electrolyte and separated by a very thin insulator

• When the plates are charged up, an opposite charge forms on either side of the separator, creating what's called an electric double-layer, maybe just one molecule thick

Supercapacitor images:

supercapacitor charging and discharging

supercapacitors

Features of supercapacitors.

• Very high rates of charge and discharge.• High cycle efficiency (95% or more).• High storage capacity.• Good Reversibility.• Low toxicity of materials used.• Works even at low temperatures -40

degrees Celsius.• Capacitance ranges to 5000 F.

Advantages and Disadvantages ofsupercapacitors.

Advantages of supercapacitors:• High power density.• Low impedense.• Simple charging methods.• Appreciable operating temp.(-40ºC to 70ºC).• Eco-friendly

Disadvantages of supercapacitors:• Low voltage per cell.• It can't be used in AC & high frequency

circuits.• High self discharge.• Low Energy density.

Applications of supercapacitors

• They're being explored as replacements for the batteries in hybrid cars.

• Back-up and UPS systems.• ultracapacitors function well in

temperatures as low as –40 C, they can give electric cars a boost in cold weather, when batteries are at their worst.

• Used in Diesel engine start up in submarines & tanks.

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