SUPERCAPACITORS also known as Electric Double Layer Capacitor or Ultra Capacitors is just like a Capacitor made up of two metal plates, but they’re usually coated with a sponge like, porous material known as activated carbon. The porous material makes the surface area a lot larger and boosts the energy density. They are immersed in an electrolyte made of positive and negative ions dissolved in a solvent. Finally, each of the Supercapacitor’s carbon electrodes ends up having two layers of charge coating on its surface, basically it is a double-layer capacitor with very high storage capacity. Typical Values range from few Farads to thousand Farads Capable of Charging within few seconds Light weight Very High Power Density (W/Kg). SUPERCAPACITORS in it's present form bridges the gap between electrolytic capacitors and rechargeable batteries. Supercapacitors can accept and deliver charge much faster than batteries, and tolerate many more charge and discharge cycles than rechargeable batteries.
SUPERCAPACITOR consist of two electrodes separated by an ion-permeable membrane (separator), and an electrolyte ionically connecting both electrodes. When the electrodes are polarized by an applied voltage, ions in the electrolyte form electric double layers of opposite polarity to the electrode's polarity. The positively polarized electrodes will have a layer of negative ions at the electrode/electrolyte interface along with a charge-balancing layer of positive ions adsorbing onto the negative layer. The opposite is true for the negatively polarized electrode. Each of the Supercapacitor’s carbon electrodes ends up having two layers of charge coating on its surface, basically it is a double-layer capacitor with very high storage capacity.
Construction of Supercapacitor
Supercapacitors consist of two metal foils (current collectors), each coated with an electrode material activated carbon which serves as power connection between the electrode material and the external terminals. The electrodes are kept apart by an ion-permeable membrane (separator) used as an insulator to protect the electrodes against short circuits. This construction is subsequently rolled or folded into a cylindrical or rectangular shape and stacked in an aluminum can or an adaptable rectangular housing. Then the cell is impregnated with a liquid or viscous electrolyte of organic or aqueous type. The electrolyte, an ionic conductor, enters the pores of the electrodes and serves as the conductive connection between the electrodes across the separator.
What is Unique about Supercapacitor
Basically Supercapacitors are energy storage device like batteries, but they store energy in an electric field, instead of through a chemical reaction the way a battery does. The beauty of this Electrochemical component “Supercapacitor” is that it can be charged in seconds rather than hours and can be used for more than 1 million recharge cycles. Unlike batteries, it is environment friendly, maintenance free, efficiency level 98%, can operate at wide temperature range of -40 deg. C to + 70 deg. C , it covers life span of 15 years and does not show ageing effect. Supercapacitors typically have 10-20 times more Power Density than normal Batteries. Supercapacitors can store and can also discharge energy very quickly and can used in thousands of different applications. Supercapacitors can complement a primary energy source like an internal combustion engine, fuel cell or a battery which cannot repeatedly provide quick bursts of power. The future horizon looks immense for Supercapacitors as a green alternative energy resource.
Where can Supercapacitors be used
Supercapacitors can be used in hundreds of applications as Stand alone or complimenting with Battery as needed. Their relatively high power density makes them ideal for parallel combination with batteries that have high energy density to ram the hybrid energy storage systems. When a load requires not constant energy, the battery system supplemented by supercapacitor allows delivering the high amount of energy in the short time period from the charged supercapacitor. This reduces a load on the battery and in many cases extends the lifetime of rechargeable batteries
How does Supercapacitors compare with Battery
Technology is developing with fast pace, but Power packs (Batteries) which powers these devices are not able to cope up with the power requirements. For example smart phones are struggling for power, Automobiles’ power demand increases by 100 Watts every year. Electric drive vehicles popularity is hampered due to limitation of Batteries. The dramatic rise of smartphones, tablets, laptops and thrust on Green Energy, Solar, Wind power, Recycling of Energy, Electric Mobility, etc has brought battery technology to the forefront of electronics research. Even as devices have improved by leaps and bounds, the slow pace of battery development has held back technological progress.
Green Energy, Mobility and Huge Data Centers are the key area to be focused for modelling sustainable Future cities.Energy may be of different variants/forms at point of Source, but in most cases point of use is in Electric form, either direct On-line or in stored mode. Electro-chemical Batteries are most popular device for Energy storage media. Environmental Hazards and human safety issues are commonly associated with use of Electro-chemical batteries, but these have been ignored on grounds of non-availability of alternative source in place of Batteries. Recent developments and Research break throughs have placed Supercapacitor in domain of Battery area.
Why Supercapacitors is looked upon as "Host of Future Energy
SUPERCAPACITOR is like the wonder child of a capacitor and a battery. It can hold a charge and dispense electricity over a long period of time like a battery, and can also take in and store energy to be released in sudden bursts like a capacitor. This makes it an excellent power source for applications where Batteries are not able to deliver, like in cold weather, Regenerative Braking, Power burst, etc. Supercapacitors are also best suited for Solar, Wind mill by improving its Run time, Supercapacitors are also capable of improving equipment uptime and power reliability. A Supercapacitor-based engine start module enables any vehicle light-duty or heavy-duty industrial vehicles and buses with diesel or petrol engines to start and operate reliably in temperatures down to -40°C. Able to start an engine when batteries can’t, Supercapacitors can completely take over the engine cranking and starting function by remaining fully charged, even if the battery voltage drops significantly. Supercapacitors in present stage of development can boost electric mobility applications ranging from 2-wheelers, 3-wheelers, cars, buses, trains, metro, trams, etc.
Beyond Automobiles and Electric vehicles, Supercapacitors could play an interesting role in powering electronic gadgets and cell phones to squeeze out extra energy and help a cell phone last longer, and charge in seconds and also for power grid during a peak demand., and host of many other applications. Supercapacitors can complement a primary energy source like an internal combustion engine, fuel cell or battery, which cannot repeatedly provide quick bursts of power. Supercapacitor is considered in a host of future energy related applications. The future horizon looks immense for Supercapacitors as a green, alternative energy resource.