Subgrid Particle Surface Film Model Reference

The Subgrid Particle Surface Film model simulates the formation and behavior of surface films that develop on active material particles due to parasitic side reactions, such as solid electrolyte interphase (SEI) or lithium plating (LiP).

You use the Subgrid Particle Surface Film model to simulate the deposition of solid phases on the surface of the particles and consider the effect of the film resistance on the overall particle behavior. The model initially calculates the film thickness by dividing the effective film phase volume by the particle phase surface area. During the simulation, the model computes the film thickness independently of the specified volume fraction or effective volume.

The Subgrid Particle Surface Film model is available as an optional model for individual porous solid phases when the following models are selected:

The Concentrated Electrolyte model is active in the physics continuum.
The Electrochemistry model is active for the porous solid film phase.

This Subgrid Particle Surface Film model is suitable for thin films with small thickness increases throughout the simulation.

注	Subgrid Particle Surface Film requires that the film phase region must be a subset of the particle phase region.

表 1. Subgrid Particle Surface Film Model Reference
Theory	See Subgrid Particle Surface Film.
Provided By	[porous phase] > Models > Electrochemistry
Example Node Path	Continua > [physics continuum] > Models > Porous Media > Porous Phases > [porous phase] > Models > Subgrid Particle Surface Film
Requires	Physics continuum selections: Space: Three Dimensional Time: Implicit Unsteady Optional Models: Electrochemistry Electrochemistry: Concentrated Electrolyte Porous Phase selections: Material: Solid Equation of State: Constant Density Optional Models: Electrochemistry An active material porous solid phase with the Subgrid Particle Intercalation Model activated, to represent the particle (porous phase) from which the solid film initiates and grows.
Properties	Particle Phase. See Subgrid Particle Surface Film Model Properties.
Activates	Materials	Elemental Composition, Ionic Resistivity, Molecular Weight. See Material Properties.
	Field Functions	See Field Functions.
	Other	Provides the ability to register solid materials in the film phase as part of the electrochemical reaction mechanism for corresponding Reacting Surface models in liquid physics continua. See Reaction [n] Reference.

Subgrid Particle Surface Film Model Properties

Particle Phase: Selects the porous solid phase that represents the subgrid particle on which the solid film forms. Only porous solid phases with an activated Subgrid Particle Intercalation Model can be selected.

Material Properties

The following material properties are available for [porous phase] > Models > [solid].

Elemental Composition

Specifies the numbers and types of atoms which form the porous phase composition.

Method	Corresponding Method Node
Elemental Composition	Elemental Composition Method Allows you to specify more than one type of atom in an porous phase. Atoms To add an atom, right-click the Atoms node and select New Atom. The Add atom to elemental composition dialog allows you to select the type and quantity of atoms in the composition. An [Atom] sub-node is created for each type of atom that is selected and the Molecular Weight property displays the combined atomic masses of the atoms within the species component. See Using the Elemental Composition Method.

Method

Corresponding Method Node

Elemental Composition

Elemental Composition Method

Allows you to specify more than one type of atom in an porous phase.

Atoms: To add an atom, right-click the Atoms node and select New Atom.; The Add atom to elemental composition dialog allows you to select the type and quantity of atoms in the composition. An [Atom] sub-node is created for each type of atom that is selected and the Molecular Weight property displays the combined atomic masses of the atoms within the species component. See Using the Elemental Composition Method.

Molecular Weight

Specifies the molecular weight for the solid film phase $M_{F}$ in Eqn. (4153).

Method	Corresponding Method Node
Elemental Composition	Elemental Composition The molecular weight is automatically updated when you change the composition of the molecule.

Ionic Resistivity: Specifies the ionic resistivity of the solid film layer. The ionic resistivity causes a potential drop as salt ions migrate through the film to react with the particle surface. This value is $σ_{i}$ in Eqn. (4155).

Field Functions

Intercalation Particle Surface Film Thickness of [porous film phase]: The (average) thickness of the film solid phase $h_{F}$ in Eqn. (4154).

Intercalation Particle Film Resistance Area of [porous particle phase]: The total electrical resistance area of all films growing on the particle $R$ in Eqn. (4155).