The main disadvantage of using supercapacitors in the field of energy storage systems is their limited voltage due to technology limits. To resolve this problem, these components are usually applied in series to reach the suitable voltage. However the tolerance in these components' characteristics leads to imbalanced voltage during the chargedischarge cycle. This may influence adversely the supercapacitors lifetime. To avoid this phenomenon, balancing circuits have to be employed. This turned out to be very useful in improving the performance and extending the lifetime of supercapacitors and the reliability of energy storage system as a whole.