NRI INSTITUTE OF INFORMATION SCIENCE & TECHNOLOGY (NIIST)

Presentation On:- SUPERCAPACITOR

CONTENTS

WHAT IS CAPACITOR INTRODUCTION OF SUPERCAPACITOR WHAT IS SUPERCAPACITOR SUPERCAPACITOR & ULTRACAPACITOR HISTORY OF SUPERCAPACITOR WHY THEY CAN STORE MORE ENERGY WHY SUPERCAPACITOR ADVANTAGE AND DISADVANTAGE APPLICATIONS SOME IMAGES OF SUPERCAPACITOR

WHAT IS CAPACITOR ?

A capacitor (originally known as condenser) is a passive two-terminal electrical component used to store energy in an electric field.

INTRODUCTION OF SUPERCAPACITORSUPERCAPACITOR also known as Electric double-layer capacitors, or electrochemical double layer capacitors (EDLCs), or ultra capacitors, are electrochemical capacitors that have an unusually high energy density when compared to common capacitors, typically on the order of thousands of times greater than a high capacity electrolytic capacitor. For instance, a typical electrolytic capacitor will have a capacitance in the range of tens of milli farads. The same size super capacitor would have a capacitance of several farads, an improvement of about two or three orders of magnitude in capacitance but usually at a lower working voltage. Larger, commercial electric double layer capacitors have capacities as high as 5,000farads

WHAT IS SUPERCAPACITOR

 A supercapacitor or ultracapacitor is an electrochemical capacitor that has an unusually high energy density when compared to common capacitors. They are of particular interest in automotive applications for hybrid vehicles and as supplementary storage for battery electric vehicles

SUPERCAPACITOR & ULTRACAPACITOR

Electric double-layer capacitors, also known as supercapacitors, electrochemical double layer capacitors (EDLCs) or ultracapacitors are electrochemical capacitors that have an unusually high energy density when compared to common capacitors.

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 currentand low voltage. In some situations, an ultracapacitor can take the place of a rechargeable low-voltage electrochemical battery.

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An excellent example of the use of an ultra capacitor can be found in so-called electrical smart meters.

Ultracapacitors can be found in emergency radios and flashlights.

The principal disadvantage of the ultracapacitor, compared with older capacitor designs, is the fact that the ultracapacitor cannot withstand high voltage. 

HISTORY OF SUPERCAPACITOR

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]. It was believed that the energy was stored in the carbon pores and it exhibited "exceptionally high capacitance", although the mechanism was unknown at that time. It was 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.].

WHY THEY CAN STORE MORE ENERGY• Electrochemical double layer capacitors (EDLC)• Store energy using ion adsorption (no faradaic (redox) reaction)• High specific surface area (SSA) electrodes (carbon) 100 – 120 F/g (nonaqueous electrolyte) 150 – 300 F/g (aqueous electrolyte). 

WHY SUPERCAPACITOR

Supercapacitors are known for over 50 years(patent of General Electric, 1957). Capacitance Supercapacitor are able to store and deliver of Earth is energy at relatively high rates (beyond those 0.0007 accessible with batteries). A specific power of 5 000 W/kg can be reached. Supercapacitor exhibit very high degree of reversibility in repetitive charge-discharge cycling. Cycle life over 500 000 cycles demonstrated

Study of the Efficiency of Supercapacitor

• Supercapacitor by constant current charging, the highest efficiency can be gotten。 Because of the serial and parallel resistance in Supercapacitor, they will consume electricity when charging. The amount of charging current will affect the charging efficiency.• Supercapacitor by constant voltage charging, the efficiency can be up to 50% • Many times experiments show that the smaller charging current can lead to higher efficiency.

Charging Efficiency under Different Charging Current

(Charging Current from 0.5A to 14A)

ADVANTAGES RELATIVE TO BATTERIES

Very high rate of charge and discharge Little degradation over hundreds of thousand

of cycles Good reversibility Low toxicity of materials used High cycle efficiency(95% or more).

DISADVANTAGES

The amount of energy stored per unit weight is considerably lower than that of an electrochemical battery(3-5 wh/kg for an ultra capacitor compared to 30-40 wh/kg for a battery).

It also only about 1/100000th the volumetric energy density of gasoline.

The voltage varies with the energy stored. To effectively store and recover energy requires sophisticated

electronic control and switching equipment. Has the highest dielectric absorption of all type of capacitor.

APPLICATIONS

Maintenance free applications Public transportation HEVs, start-stop system Back-up and UPS system System of energy recuperation Consumers electronics

IMAGES OF CAPACITOR

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