Comparing the degradation effect of a 'two-cell' Supercapacitor-module with and without voltage equalization circuit(s) under experimental self-discharge and load cycling tests

The problem of over-voltage is common in SC modules under cycling conditions. To prevent this, the voltage equalization circuit is usually used as a tool to balance SC cells in a module to increase the life expectancy of the system. There is lack of detailed experimental analysis on its performance on degradation proximity testing. This paper therefore focuses on demonstrating the importance of voltage equalization circuits specifically on their performance in degradation proximity between two-cell modules experimentally. Three types of common active balancing equalization circuits were first tested and the best performing circuit was used to compare with a commercial Maxwell voltage equalization circuit under self-discharge and load cycling tests after 1115 h of continuous cycles under high temperature. The periodic capacitance (C) and ESR parameters calculated from charge-discharge characterization test results over 1115 h shows that the active balancing circuit produced a more even/balance parameter regression between each two-cells in a module over time.