Electrochemical Capacitor Voltage Balance: Cell Uniformity Requirements for High-voltage Devices
John R. Miller

Abstract

This paper presents results from our investigation of cell uniformity requirements for high-voltage electrochemical capacitors (ECs). A lumped element equivalent circuit model is first derived to simulate the electrical response of a single cell. Complex impedance data is used for this. Then a high voltage EC model is created by series connecting these single-cell circuits. Finally, model performance is statistically evaluated using a Monte Carlo analysis. Both static and dynamical performance is reported. Cell voltages are obtained as a function of the specified tolerances for each element in the single-cell equivalent circuit model.

The presented approach establishes the relationship between cell uniformity specifications and the maximum average cell voltage that a multicell EC can be operated at reliably. This approach can readily be extended to include thermal manage ment specifications.