Supercapacitors usually operate at low voltages of around 2.7 V. In order to reach higher operating voltages, it is necessary to build a cascade of serial connected SC cells. Due to production or aging related variations in capacitance and insulation resistance the voltage drop over individual capacitors may exceed the rated voltage limit. Thus, a balancing system is required to avoid accelerated aging of the capacitor cell.
Source:
Würth Elektronik
