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1D Lithium-Ion Battery Model for the SEI Formation Tutorial
Introduction
This is a template model containing the physics, geometry, and mesh of a lithium-ion battery (without any SEI (solid-electrolyte-interface) reactions or mechanisms added). The SEI Formation in a Lithium-Ion Battery application available in the Application Library makes use of this model setup.
The battery cell model is created using the Lithium-Ion Battery interface. A more detailed description on how to set up this type of model can be found in the model example 1D Isothermal Lithium-Ion Battery.
Model Definition
The model is set up for a graphite/NCA battery cell. The materials are available from the Battery material library and mainly default settings are selected. The model domains consist of:
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Negative porous electrode: Graphite (MCMB LixC6) active material
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Separator
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Positive porous electrode: NCA (LiNi0.8Co0.15Al0.05O2) active material
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Electrolyte: 1.0 M LiPF6 in EC:EMC (3:7 by weight)
The Lithium-Ion Battery interface accounts for:
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Electronic conduction in the electrodes
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Ionic charge transport in the electrodes and electrolyte/separator
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Material transport in the electrolyte, allowing for the introduction of the effects of concentration on ionic conductivity and concentration overpotential
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Material transport within the spherical particles that form the electrodes
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Butler–Volmer electrode kinetics using experimentally measured discharge curves for the equilibrium potential
Application Library path: Battery_Design_Module/Lithium-Ion_Batteries,_Aging_and_Abuse/sei_formation_seed
Modeling Instructions
From the File menu, choose New.
New
In the New window, click  Model Wizard.
Model Wizard
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In the Model Wizard window, click  1D.
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In the Select Physics tree, select Electrochemistry > Batteries > Lithium-Ion Battery (liion).
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Click Add.
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Click  Study.
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In the Select Study tree, select Preset Studies for Selected Physics Interfaces > Time Dependent with Initialization.
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Click  Done.
Root
Add the model parameters from a text file.
Global Definitions
Parameters 1
1
In the Model Builder window, under Global Definitions click Parameters 1.
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In the Settings window for Parameters, locate the Parameters section.
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Click  Load from File.
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Browse to the model’s Application Libraries folder and double-click the file sei_formation_parameters.txt.
Geometry 1
Interval 1 (i1)
1
In the Model Builder window, under Component 1 (comp1) right-click Geometry 1 and choose Interval.
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In the Settings window for Interval, locate the Interval section.
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From the Specify list, choose Interval lengths.
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In the table, enter the following settings:
Lengths (m)
L_neg
L_sep
L_pos
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Click  Build All Objects.
Materials
Load the materials from the material library.
Add Material
1
In the Materials toolbar, click  Add Material to open the Add Material window.
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Go to the Add Material window.
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In the tree, select Battery > Electrolytes > LiPF6 in 3:7 EC:EMC (Liquid, Li-ion Battery).
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Right-click and choose Add to Component 1 (comp1).
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In the tree, select Battery > Electrodes > Graphite, LixC6 MCMB (Negative, Li-ion Battery).
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Right-click and choose Add to Component 1 (comp1).
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In the tree, select Battery > Electrodes > NCA, LiNi0.8Co0.15Al0.05O2 (Positive, Li-ion Battery).
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Right-click and choose Add to Component 1 (comp1).
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In the Materials toolbar, click  Add Material to close the Add Material window.
Definitions
Explicit selections are made in the model geometry.
Negative Electrode
1
In the Definitions toolbar, click  Explicit.
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In the Settings window for Explicit, type Negative Electrode in the Label text field.
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Select Domain 1 only.
Separator
1
In the Definitions toolbar, click  Explicit.
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In the Settings window for Explicit, type Separator in the Label text field.
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Select Domain 2 only.
Positive Electrode
1
In the Definitions toolbar, click  Explicit.
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In the Settings window for Explicit, type Positive Electrode in the Label text field.
3
Select Domain 3 only.
Lithium-Ion Battery (liion)
1
In the Model Builder window, under Component 1 (comp1) click Lithium-Ion Battery (liion).
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In the Settings window for Lithium-Ion Battery, locate the Cross-Sectional Area section.
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In the Ac text field, type A_cell.
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Locate the Cell Settings section. Select the Define cell state of charge (SOC) and initial charge inventory checkbox.
SOC and Initial Charge Distribution 1
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In the Model Builder window, under Component 1 (comp1) > Lithium-Ion Battery (liion) click SOC and Initial Charge Distribution 1.
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In the Settings window for SOC and Initial Charge Distribution, locate the State-of-Charge Definition section.
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From the list, choose User defined. In the Ecell0%SOC text field, type E_cell_0SOC.
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In the Ecell100%SOC text field, type E_cell_100SOC.
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Locate the Initial Cell Charge Distribution section. From the Define by list, choose Cell voltage.
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In the Ecell,0 text field, type E_min.
Negative Electrode Domain Selection 1
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In the Model Builder window, click Negative Electrode Domain Selection 1.
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In the Settings window for Negative Electrode Domain Selection, locate the Domain Selection section.
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From the Selection list, choose Negative Electrode.
Positive Electrode Domain Selection 1
1
In the Model Builder window, click Positive Electrode Domain Selection 1.
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In the Settings window for Positive Electrode Domain Selection, locate the Domain Selection section.
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From the Selection list, choose Positive Electrode.
Separator 1
1
In the Model Builder window, under Component 1 (comp1) > Lithium-Ion Battery (liion) click Separator 1.
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In the Settings window for Separator, locate the Porous Matrix Properties section.
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In the εl text field, type epsl_sep.
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Locate the Effective Transport Parameter Correction section. From the Electrolyte conductivity list, choose User defined. In the fl text field, type epsl_sep^brugl_sep.
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From the Diffusion list, choose User defined. In the fDl text field, type epsl_sep^brugl_sep.
Porous Electrode 1
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In the Physics toolbar, click  Domains and choose Porous Electrode.
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In the Settings window for Porous Electrode, locate the Domain Selection section.
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From the Selection list, choose Negative Electrode.
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Locate the Electrode Properties section. In the σs text field, type sigmas_neg.
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Locate the Porous Matrix Properties section. In the εs text field, type epss_neg.
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In the εl text field, type epsl_neg.
Particle Intercalation 1
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In the Model Builder window, click Particle Intercalation 1.
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In the Settings window for Particle Intercalation, locate the Material section.
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From the Particle material list, choose Graphite, LixC6 MCMB (Negative, Li-ion Battery) (mat2).
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Locate the Particle Transport Properties section. In the rp text field, type rp_neg.
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Click to expand the Particle Discretization section. In the Nel text field, type 5.
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Select the Fast assembly in particle dimension checkbox.
Porous Electrode Reaction 1
1
In the Model Builder window, click Porous Electrode Reaction 1.
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In the Settings window for Porous Electrode Reaction, locate the Material section.
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From the Material list, choose Graphite, LixC6 MCMB (Negative, Li-ion Battery) (mat2).
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Locate the Electrode Kinetics section. In the i0,ref(T) text field, type i0ref_neg.
Porous Electrode 2
1
In the Physics toolbar, click  Domains and choose Porous Electrode.
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In the Settings window for Porous Electrode, locate the Domain Selection section.
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From the Selection list, choose Positive Electrode.
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Locate the Electrode Properties section. In the σs text field, type sigmas_pos.
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Locate the Porous Matrix Properties section. In the εs text field, type epss_pos.
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In the εl text field, type epsl_pos.
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Locate the Effective Transport Parameter Correction section. From the Electrolyte conductivity list, choose User defined. In the fl text field, type liion.epsl^brugl_pos.
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From the Diffusion list, choose User defined. In the fDl text field, type liion.epsl^brugl_pos.
Particle Intercalation 1
1
In the Model Builder window, click Particle Intercalation 1.
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In the Settings window for Particle Intercalation, locate the Material section.
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From the Particle material list, choose NCA, LiNi0.8Co0.15Al0.05O2 (Positive, Li-ion Battery) (mat3).
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Locate the Particle Transport Properties section. In the rp text field, type rp_pos.
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Locate the Particle Discretization section. In the Nel text field, type 3.
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Select the Fast assembly in particle dimension checkbox.
Porous Electrode Reaction 1
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In the Model Builder window, click Porous Electrode Reaction 1.
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In the Settings window for Porous Electrode Reaction, locate the Material section.
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From the Material list, choose NCA, LiNi0.8Co0.15Al0.05O2 (Positive, Li-ion Battery) (mat3).
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Locate the Electrode Kinetics section. In the i0,ref(T) text field, type i0ref_pos.
Electric Ground 1
1
In the Physics toolbar, click  Boundaries and choose Electric Ground.
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Select Boundary 1 only.
Global Definitions
Default Model Inputs
Set up the temperature value used in the entire model.
1
In the Model Builder window, under Global Definitions click Default Model Inputs.
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In the Settings window for Default Model Inputs, locate the Browse Model Inputs section.
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In the tree, select General > Temperature (K) - minput.T.
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Find the Expression for remaining selection subsection. In the Temperature text field, type T.
Definitions
Piecewise 1 (pw1)
1
In the Definitions toolbar, click  Piecewise.
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In the Settings window for Piecewise, type K in the Function name text field.
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Locate the Definition section. From the Smoothing list, choose Continuous function.
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Find the Intervals subsection. Click  Load from File.
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Browse to the model’s Application Libraries folder and double-click the file sei_formation_piecewise.txt.
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Click  Plot.
Variables 1
1
In the Model Builder window, right-click Definitions and choose Variables.
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In the Settings window for Variables, locate the Variables section.
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Click  Load from File.
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Browse to the model’s Application Libraries folder and double-click the file sei_formation_variables.txt.
Study 1
Step 2: Time Dependent
1
In the Model Builder window, under Study 1 click Step 2: Time Dependent.
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In the Settings window for Time Dependent, locate the Study Settings section.
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In the Output times text field, type range(0,180,t_cycling).