Edge Electrode
The Edge Electrode can be used in 3D problems to define electrodes such as long pipes and thin wires where the electric potential variation within the electrode in the normal direction to the electrode surface is negligible. This assumption allows for the thin electrode domain to be replaced by a lumped one-dimensional partial differential equation formulation on the edge, describing an electrode surface along the edge with a given Edge electrode radius. In this way the problem size can be reduced, and potential problems with mesh anisotropy in the thin layer can be avoided.
The electric current conduction in the tangential direction of an edge can be described by Ohm’s law or a Fixed electric potential or a Floating potential assuming infinite conductivity of the edge or an External short electric potential which allows to connect two electrodes over an external connector with a given bulk resistance or a Connection point electric potential which allows to define a location for connections to other locations in the model.
An Edge Electrode can only be applied to edges within, or adjacent to, Electrolyte domains.
A default Electrode Reaction subnode is added by default to the feature. Double Layer Capacitance, Electric Ground, Electric Potential, and Electrode Current subnodes can also be added to the feature.
Dissolving-Depositing Species
Use the settings of this section to define species that participate in dissolution-deposition electrode reactions o n the edge electrode, for instance metal deposition/dissolution or oxide formation.
Use the Add () and Delete () buttons as needed in the tables to control the number of species.
Dependent variables for the molar concentration (SI unit: mol/m) are added for each dissolving-depositing species. These variables can be used to keep track of the amount of reacted material on the electrode. The total molar dissolution/deposition rate depends on the reaction rates and stoichiometry, defined in the Electrode Reaction subnodes.
The Density and Molar mass determine the electrode growth velocity and the resulting dissolved/deposited layer thickness, so that the change in the edge electrode radius also can be calculated. By use of the Add volume change to edge radius check box you may define if this volume change should be included in the model.
A thickness variable is also defined. Use it, for instance, to couple to the Film Resistance (see below).
Decorative Plating: Application Library path Electrodeposition_Module/Tutorials/decorative_plating
Film Resistance
See the Electrode Surface node. The section is only available when a Secondary current distribution has been selected on the parent node.
Constraint Settings
To display this section, click the Show More Options button () and select Advanced Physics Options in the Show More Options dialog box.
The mesh size in the perpendicular direction to the edge should preferably be in the same order of magnitude as the Edge electrode diameter in order to achieve good numerical accuracy.