The concept of supercapacitors has been around for years and are found many nice applications in real-life. Offering a very high capacitance in terms of small size, the supercapacitor actually resembles to a regular capacitor. The supercapacitor charges by applying a differential voltage to the negative and positive plates.
From manufacturing perspective, the supercapacitor is a mix between a capacitor and a battery. While the capacitor is built of conductive foils and dry separators, supercapacitor uses electrodes and a special electrolyte. There are three types of electrode materials the electrodes are usually made of:
1. high surface area activated carbons (the easiest to use and most economical material suitable for supercapacitors)
2. conducting polymers
3. metal oxide
Here is the supercapacitor principle explained:
The electrolyte’s nature may be either organic or aqueous. The amount of energy the supercapacitor can store is measured in µF (microfarads) or nanofarads or even picofarads for smaller.
In practice, supercapacitors are especially used as a replacement for the electrochemical battery, for standby power and memory backup devices as well as in filtering of pulsed load currents.
The charging time for supercapacitor varies from a few seconds for low impedance devices to several minutes.
But let’s see which are the Advantages and Disadvantages of Supercapacitors
1. Unlimited cycle life; as compared to the electrochemical battery, they are not subject to the wear or aging.
2. On-hand charge methods; no full-charge circuit required.
3. Quick charging times
4. Low impedance; by paralleling it with a battery, it enhances the pulse current.
5. Cost effective storage; a very high cycle count compensates the lower density.
1. Low energy density; usually holds 1/5 – 1/10 of a battery.
2. Cannot use the full energy spectrum for some applications.
3. Low voltage cells; to get higher voltages, serial connections are required.
4. Voltage balancing needed; when more than 3 supercapacitors are connected in series, the circuit needs a voltage balancing element.
5. High self-discharge as compared to electrochemical batteries