Using a Debye polarization cell to predict double-layer capacitor performance

Many different circuit models have been proposed for double-layer capacitors (DLCs). Presented in this paper is an evaluation of the Debye polarization cell as a model for a double-layer capacitor (DLC). In comparison to other circuit models, the primary advantage of this model is that the circuit elements can be related to chemical reactions which occur inside the DLC. The circuit element values are found from AC impedance measurements for a DLC and a computer program which utilizes a nonlinear least-squares fitting technique. Variations in circuit element values with DC bias level and manufacturing have been investigated. The performance of the Debye polarization cell in slow discharge and pulse load applications has been compared to actual circuit measurements and to simulated results using a classical equivalent circuit.