Series-Parallel Reconfigurable Electric Double-Layer Capacitor Module with Cell Equalization Capability, High Energy Utilization Ratio, and Good Modularity

Voltages of electric double-layer capacitor (EDLC) modules vary rather wider than traditional secondary batteries. Although EDLCs should desirably be cycled in a voltage range as wide possible to achieve high energy utilization ratio, the variation EDLC impairs performance DC–DC converters. To address such issues, previous works reported series-parallel reconfiguration techniques, which are roughly divided into balance- and unbalance-shift circuits. However, conventional balance-shift circuits not applicable comprising odd number cells, impairing modularity. Unbalance-shift circuits, on other hand, unavoidably cause cell imbalance that reduces ratio. This paper proposes novel reconfigurable module with equalization capability. The proposed is any realizing good Furthermore, all cells can charged discharged uniformly without generating imbalance, achieving an improved ratio compared techniques. A five-cell prototype was built for experimental verification. While varied between 1.04 2.83 V, from 2.5 0.3 V. result equivalent 98.6%