The increasing demand for supercapacitors is driven by the increasing application of instantaneous backup power sources.

The increasing demand for supercapacitors is driven by the increasing application of instantaneous backup power sources. 

Supercapacitors, also known as ultra capacitors, are electrochemical capacitors that have the ability to store more energy than conventional capacitors. Supercapacitors can charge and provide energy faster than batteries. The power and energy density of conventional capacitors, supercapacitors, conventional batteries, and fuel cells.

The significant advantage of supercapacitors is that they can cycle thousands of times before aging, while batteries can only cycle hundreds of times. In addition, batteries have the ability to perform deep discharge compared to supercapacitors. Due to the decomposition voltage of electrolytes, the rated values of most supercapacitors are 2.7V-4.2V.

The development of supercapacitors has introduced lithium-ion hybrid capacitors that can be charged to higher voltages, which have less self discharge and therefore have higher energy density. The disadvantage of these supercapacitors is that they cannot discharge below approximately 2.4V, otherwise they will be damaged.

The composition of supercapacitors makes their self discharge rate significantly higher than that of batteries. The higher the working temperature of a supercapacitor, the higher the charging voltage, and the faster the aging; The capacitance of a supercapacitor will decrease and the equivalent series resistance (ESR) will increase. This means that supercapacitors can provide less energy for applications. The energy of a supercapacitor can be expressed using formula 1: (1) W is the energy provided by the supercapacitor, C is the capacitance of the supercapacitor, and V is the voltage of the supercapacitor. The ESR of capacitors increases the power loss of the system. The effects of temperature and voltage on the aging of supercapacitors. A temperature increase of only 10 ° C can reduce the lifespan of supercapacitors by half. In addition, the usual practice is to charge the supercapacitor to a voltage lower than the nominal voltage to increase its lifespan. Due to the charging voltage of supercapacitors being between 2.7V and 4.2V, it is necessary to connect several supercapacitors in series for most applications. Therefore, it is necessary to balance supercapacitors; Otherwise, one unit may charge more than another unit, leading to unequal capacitor aging and reducing the ability of the capacitor bank to provide the required energy for the application.

The methods used for balancing supercapacitors include passive balancing using resistor strings, using switch resistors, using Zener diodes, and active balancing. The first three methods can cause power loss in resistors, while the fourth method is the most effective but also the most expensive.

When supercapacitors are used for backup power applications, their capacitance and ESR must be monitored to ensure that they can provide the energy required for the application. It is a supercapacitor manager that can track the capacitance and ESR of supercapacitor banks; It can also monitor other important data, such as temperature, voltage, current, and safety conditions. Can notify the host if the capacitor bank is weak and balance it. It is an efficient switch mode supercapacitor charger that can charge capacitor banks from 2.1V to 2.6V.