About super capacitor

                                  Super capacitor

Super capacitor is an advance version of the conventional electrolytic capacitor. It is also known as the ultra capacitor, electric double layer capacitor or electrochemical double layer capacitor. It is a special type capacitor that has high energy density and this energy density is usually hundreds of times greater than conventional electrolytic capacitors. It also has a much higher power density than batteries or fuel cells. Super capacitor is used for energy storage rather than as general-purpose circuit components. It has a variety of commercial applications, notably in "energy smoothing" and momentary-load devices. Ultra capacitor also has applications as energy-storage because it can quickly charge. Due to same reason, it is extremely essential for domestic solar energy system.

Series connected super capacitor

Voltage increased by series connection of Ultra capacitor

Basic idea:

Conventional capacitor has two metallic plates which are separated by insulation. When a voltage source connects with capacitor, then charges flow through capacitor and capacitor is charged. In this way a potential difference creates within two plates of capacitor. There is used a dielectric material between the plates. Voltage of capacitor can be controlled by dielectric, but ultra capacitor can not be controlled by conventional dielectric.

Electric double layer capacitor also has two metal plates which are coated with activated carbon and separated by an intervening insulator. It uses virtual plates which are in fact two layers of the identical substrate. Due to its electrochemical properties, it is called electrical double layer. It has two electrodes positive and negative. Capacitor capacitance can be increased by increasing surface area of each electrode or decreasing distance between electrodes. As a result, stored energy of the capacitor, which directly proportional to capacitance, also increases. Super capacitor has two electrodes with much higher areas and much thinner dielectrics. These dielectrics decrease the distance between two electrodes. These implementations help to increase capacitance and stored energy in super capacitor.

Super capacitor has low voltage, but it can be increased by series combination of matched super capacitors. Ultra capacitor has much higher power density than batteries. If power density is high, energy will quickly deliver to the load (electronic equipments).Movement of charge is slow in Batteries means power density is low than super capacitors. So, batteries delivery speed of charge is slow and charge discharge time also relatively slow. 

  

Applications:

Some electric vehicle manufacturers are using ultra capacitors for acceleration. Super capacitor also appears in hundreds of other applications, from cell phone base stations to alarm clocks (as backup power) to audio systems. Ultra capacitor is also used in electric power grid. When transmission lines operate below full capacity, Ultra capacitors banks could be set up to absorb power surges and enable transmission lines to activate near to 100% capacity.

Super capacitor is used in vehicle for acceleration 

Advantages:

Super capacitor has low cost per cycle, good reversibility, very high rates of charging and discharging ability. It also has high output power. It can be used in simple charging method. It is free from overcharging and need not any full-charge detection. 

Electrochemical double layer capacitor