Comparison & Differences Between Capacitor, SuperCapacitor & Battery
Capacitors & batteries both operate similarly considering they both store & provide charge. However, there are some important differences in their charging & discharging characteristics that define their usage & applications.
A capacitor is a passive electronic component made up of two conductive plates & an insulator (dielectric) in-between. It stores charge between its plates in the form of an electric field.
When a current is supplied to the capacitor, the dielectric stops the current flow, due to which, the charge builds up between the plates as an electrostatic field.
Supercapacitors are considered between capacitors & batteries. It consists of two metal plates (electrodes) with an electrolyte in-between. There is an ion-permeable membrane between the plates that allow the transfer of ions.
It stores energy between the ions of the electrolyte & electrode in a double layer of charge. When the voltage is applied to the supercapacitor, the ions inside the electrolyte build up upon each electrode. There are no chemical reactions between the electrolyte & electrode.
The battery is an active component made up of two types of metal plates called Anode (positive terminal) & Cathode (negative terminal) & an electrolyte.
It stores charge in the form of chemical energy through chemical reactions between the electrodes & the electrolyte. This chemical energy converts into electrical energy and provides a constant voltage across its terminals. The fact that it stores charge in its electrolyte which provides a large volume for charge storage, increase its charge capacity tremendously.
- A capacitor stores energy in an electrical field between its plates while a battery stores energy in a chemical form by means of chemical reactions.
- A capacitor can charge & discharge quickly as compared to a battery because the chemical reactions inside a battery take a certain delay to convert into electrical energy & vice versa.
- During discharging, the output voltage of a capacitor decrease linearly. However, the battery provides a constant output voltage.
- The fact that the battery stores energy in chemical form provides high energy density than a capacitor.
- The batteries have a limited current & voltage ratings while capacitors can withstand heavy load currents and voltages.
- The capacitors have high leakage current compared to a battery.
- Capacitors have high-temperature tolerance while batteries are more temperature sensitive.
- The size of the battery is comparatively small as compared to capacitor considering they have same charge capacity.
- Batteries have limited life cycles of approximately 500 while the capacitors have longer life cycles.
- A battery is used in DC circuits while capacitors are used in DC as well as AC circuits.
- The battery can store charge for a long duration thus it is used as a primary source for powering circuits. While the capacitor holds the charge for a short duration thus it is not used as a source.
- A capacitor can withstand heavy current & voltage spikes which makes it a good surge absorber while the battery cannot tolerate high voltages and current.