Analysis of a Model for an Electrochemical Capacitor

作者：Somasundaram Karthik^*; Birgersson Erik; Mujumdar Arun Sadashiv

来源：Journal of the Electrochemical Society, 2011, 158(11): A1220-A1230.

DOI：10.1149/2.062111jes

An isothermal model for an electrochemical capacitor is presented, analyzed and discussed. In essence, the model accounts for the transient conservation of species and charge in the solid and the electrolyte phase; two main length scales are considered: one corresponding to the entire cell (macroscale) and the other for the active material in the porous electrodes (microscale). Based on an electrochemical capacitor with Ruthenium dioxide electrodes, a scaling analysis is carried out after calibration and validation with experiments, for which good agreement is found. The analysis allows us to not only secure the relevant scales and nondimensional numbers characterizing an electrochemical capacitor, but also to identify limits at which the model can be reduced to a one-dimensional counterpart on the macroscale. Furthermore, a quasi-steady state can be achieved under certain conditions at the microscale, which leads to the elimination of the radial coordinate from the system of governing equations. These findings, in turn, lead to reduced model formulations that are computationally efficient and promising for inclusion in detailed stack models. The latter is explored by emulating stacks of ten and hundred cells. Finally, the inclusion of the equation of change for energy and heat generation is discussed.

• 出版日期2011