Battery Cells Reference

0D Battery Cells

0D battery cells are created directly in Simcenter STAR-CCM+.

Battery cells that are created directly in Simcenter STAR-CCM+ are defined using the following properties and child nodes. When the configuration of a battery cell element, such as a table, is incomplete, a caution symbol appears on the battery cell node () and relevant sub-nodes ().

User Defined Battery Cell

Right-Click Actions

Select Battery Cell Models…

Opens the Select Battery Cell Models dialog in which you select the desired battery cell models; the RCR Model and/or the Heat Release Model and Vent Model.

If the RCR Model is selected, new Models > RCR Equivalent Circuit Model and RCR Equivalent Circuit Model > Parameter Tables nodes are created.

If the Heat Release Model is selected, new Models > Thermal Runaway Heat Release Model, Thermal Runaway Heat Release Model > Heat Rate, and Heat Rate > Table(Temperature) nodes are created.

If the Battery Vent Model is selected, a new Models > Thermal Runaway Battery Vent Model node is created.

User Defined Battery Cell > Models > RCR Equivalent Circuit Model

Right-Click Actions

Extract RCR Parameters from TBM File

Opens the Import Battery Data From File dialog in which you navigate to and select the .tbm file from which to import the battery cell data.

Upon selection of the .tbm file, multiple User Defined Battery Cell > Models > RCR Equivalent Circuit Model > Parameter Tables > [RCR table] nodes are created—each RCR table represents a set of RC elements at a single set of conditions. An example of an RCR table is given in RCR Table Reference.

Simcenter STAR-CCM+ automatically converts the values in the .tbm file for $R_o$ and $R_p$ from Ohms/m² to Ohms by accounting for the active area. See RCR Table Values Imported From .tbm Files.

If no tables are found using the selected .tbm file, a warning is displayed.

Extract RCR Parameters from Amesim File

Opens the Import Battery Data From Directory dialog in which you navigate to and select the folder that contains the Amesim fitting tool data.

Simcenter STAR-CCM+ parses all of the files within the folder then creates data tables and appropriate RCR parameter tables. The Output window displays the progress and states the number of RCR tables that are imported from the Amesim battery model.

The imported RCR tables appear under the User Defined Battery Cell > Models > RCR Equivalent Circuit Model > Parameter Tables node. Each RCR table represents a set of RC elements at a single set of conditions. An example of an RCR table is given in RCR Table Reference.

User Defined Battery Cell > Models > RCR Equivalent Circuit Model > Parameter Tables

Right-Click Actions

New

Creates a Tables > [RCR table] node for which you can specify the table parameters for a set of conditions—for example, at a set temperature and current.

See RCR Table Reference

User Defined Battery Cell > Models > RCR Equivalent Circuit Model > Voltage Table

Appears when the Use Voltage Table property is activated under the User Defined Battery Cell > Models > RCR Equivalent Circuit Model node.

Properties

Table

Allows you to select a previously-imported table (stored within the Tools > Tables node) which represents the equilibrium voltage. The table format is two columns—one representing state of charge (SOC) and one representing the corresponding equilibrium voltage (volts).

SOC [1-0]

The heading of the column in the table that represents the state of charge (SOC) fraction, with 0 being fully discharged and 1 being fully charged.

E, Volts

The heading of the column in the table that represents the equilibrium voltage (volts).

Interpolation Type

Specify the method that Simcenter STAR-CCM+ uses to interpolate between data values that are given in the voltage table. Choose from:

• Linear: linear interpolation
• Monotonic: monotonic cubic interpolation
• Bezier: Bezier spline interpolation

User Defined Battery Cell > Models > RCR Equivalent Circuit Model > Entropy Table

Appears when the Use Entropy Table property is activated under the User Defined Battery Cell > Models > RCR Equivalent Circuit Model node.

Properties

Table

Allows you to select a previously-imported table which represents an entropy curve (.eql file) that is stored within the Tools > Tables node. The table format is two columns—one representing state of charge (SOC) and one representing the corresponding first derivative of voltage with respect to temperature (dE/dT, mV/K).

SOC [1-0]

The heading of the column in the table that represents the state of charge (SOC) fraction, with 0 being fully discharged and 1 being fully charged.

Entropy, mV/K

The heading of the column in the table that represents the entropy (the first derivative of voltage with respect to temperature (dE/dT, mV/K)).

Interpolation Type

Specify the method that Simcenter STAR-CCM+ uses to interpolate between data values that are given in the entropy table. Choose from:

• Linear: linear interpolation
• Monotonic: monotonic cubic interpolation
• Bezier: Bezier spline interpolation

User Defined Battery Cell > Models > RCR Equivalent Circuit Model > Diffusion Resistance

Appears when the Use Diffusion Resistance property is activated under the User Defined Battery Cell > Models > RCR Equivalent Circuit Model node.

Properties

You can modify the following properties to account for diffusion resistance:

Ad

User-specified coefficient used in Eqn. (4403).

Bd

User-specified coefficient used in Eqn. (4403).

Warburg Time Offset

$t_w$ in Eqn. (4403).

Warburg Activation Energy

$E_{a,w}$ in Eqn. (4403).

User Defined Battery Cell > Models > RCR Equivalent Circuit Model > Rp Rate Effect

Appears when the Use Rp Rate Effect property is activated under the User Defined Battery Cell > Models > RCR Equivalent Circuit Model node.

Properties

The polarization resistance Rp decreases when the current passing through the cell increases. This behavior is associated with Tafel kinetics. You can modify the following constants to account for polarization resistance.

i0

The rate effect constant $i_{p,0}$ in Eqn. (4404).

i1

The rate effect constant $i_{p,1}$ in Eqn. (4404).

User Defined Battery Cell > Models > Thermal Runaway Heat Release Model

Properties

Maximum Releasable Energy

Sets the maximum releasable energy of the battery. Maximum releasable energy is the amount of energy that can be liberated by the battery when it undergoes thermal runaway. It is dependent on the physical and chemical properties of the battery cell.

Apply Model Constraints

When activated, a new node Thermal Runaway Heat Release Model > Model Activation Constraints appears. See Thermal Runaway Heat Release Model—Model Activation Constraints.

User Defined Battery Cell > Models > Thermal Runaway Heat Release Model > Model Activation Constraints

The model activation constraints allow you to specify one or more criteria that control the activation of the Thermal Runaway Heat Release model. These criteria verify if a selected field variable, for example temperature, is in a given range. To determine the value of this field variable, the selected Field Function is evaluated over the Core Parts that you assign to the battery module cell using one of the Evaluation Methods that you specify.

For more information about the core parts that you assign to the battery module cell, see Battery Modules Reference: [Battery Module Cell] Core Parts.

Right-Click Actions

New

Adds a new node, Thermal Runaway Heat Release Model > Model Activation Constraints > Model Constraint 1, which is a new model activation constraint.

Model Activation Constraints > [model constraint]

Properties

Field Function

Selects the field function that the constraint uses.

Range Operation

Selects one of two range operations to define the criterion at which the Thermal Runaway Heat Release model activates.

• >=: when the value of the selected Field Function is greater than or equal to Value, the Thermal Runaway Heat Release model activates.
• <=: when the value of the selected Field Function is less than or equal to Value, the Thermal Runaway Heat Release model activates.

Value

Specifies the limiting value for the Range Operation.

Evaluation Method

Selects the method to evaluate the field variable.

• Volume Average: The specified Field Function is volume-averaged over the Core Parts that you assign to the battery module cell.
• Maximum: The maximum value of the specified Field Function is evaluated on the Core Parts that you assign to the battery module cell.

Thermal Runaway Heat Release Model > Heat Rate

Heat Rate Right-Click Actions

The following actions are available when a heat rate table is imported within the Tools > Tables node. The table format is two columns—one representing the heat rate in Watts, and the other representing either the corresponding temperature of the battery in Kelvin or the time in seconds, depending on the type of heat rate table imported.

Tabulate Heat Rate…

Opens the Tabular Data dialog which displays the imported heat rate table data in table format within Simcenter STAR-CCM+. By clicking Export, the Save dialog opens and the data can be saved as a .csv file to a location of your choice.

Plot Heat Rate Table

Creates and opens a User Defined Battery Cell Heat Rate Plot which uses the data from the imported heat rate file.

Heat Rate Properties

Method

Selects the method used to look up the self-heating rate of your battery cell.

Field Function

Select this option when you want to specify the input for the volumetric heat source to the battery cell (W/m³) as a field function.

Table(Temperature)

Select this option when the experimental heat rate data is measured as a function of temperature.

Table(Time)

Select this option when the experimental heat rate data is measured as a function of time.

Heat Rate > Table(Temperature)

Table

Selects a previously imported table from the Tools > Tables node that contains the heat rate of the battery as a function of temperature.

Temperature, K

The heading of the column in the table that represents the temperature of the battery.

Heat Rate, W

The heading of the column in the table that represents the heat rate of the battery.

Interpolation Type

Specifies the method that Simcenter STAR-CCM+ uses to interpolate between data values that are given in the heat rate table. Choose from:

• Linear—uses linear interpolation
• Spline (Bezier)—uses Bezier spline interpolation

Extrapolate Table

When activated, the data values given in the heat rate table are extrapolated if the battery temperature exceeds the temperature range in the table during the simulation. During extrapolation, if the extrapolated heat rate is negative, it is bounded to zero.

Temperature Type

Selects the method to evaluate the temperature that is used to calculate the cell's self-heating rate during the thermal runaway event.

• Volume Average: The volume-averaged temperature, evaluated over the Core Parts that you assign to the battery module cell, is used to look up the heat rate.
• Maximum: The maximum temperature, evaluated on the Core Parts that you assign to the battery module cell, is used to look up the heat rate.
• Local Field Value: The local temperature of each cell in the battery module mesh, that is, in the Core Parts, is used to look up the heat rate, which is then converted to volumetric heat and applied to the mesh cells.

Heat Rate > Table(Time)

Table

Selects a previously imported table from the Tools > Tables node that contains the heat rate of the battery as a function of time.

Time, s

The heading of the column in the table that represents the time elapsed since the onset of thermal runaway.

Heat Rate, W

The heading of the column in the table that represents the heat rate of the battery.

Interpolation Type

Specifies the method that Simcenter STAR-CCM+ uses to interpolate between data values that are given in the heat rate table. Choose from:

• Linear—uses linear interpolation
• Spline (Bezier)—uses Bezier spline interpolation

Extrapolate Table

When activated, the data values given in the heat rate table are extrapolated if the battery temperature exceeds the temperature range in the table during the simulation. During extrapolation, if the extrapolated heat rate is negative, it is bounded to zero.

User Defined Battery Cell > Models > Thermal Runaway Battery Vent Model

Right-Click Actions

The following actions are available when a vent rate table is imported within the Tools > Tables node. The table format is three columns—one representing the mass flow rate of the venting gas in kg/s, one representing the corresponding venting gas temperature in Kelvin, and one representing the corresponding time in seconds.

Tabulate Vent Rate…

Opens the Tabular Data dialog which displays the imported vent rate table data in table format within Simcenter STAR-CCM+. By clicking Export, the Save dialog opens and the data can be saved as a .csv file to a location of your choice.

Plot Vent Rate Table

Creates and opens two plots, a User Defined Battery Cell Vent Model Temperature Plot and a User Defined Battery Cell Vent Model Mass Flow Rate Plot which use the data from the imported vent rate file.

Properties

Table

Allows you to select a previously imported table that represents the vent rate and temperature of the battery venting gas that is stored within the Tools > Tables node.

Time, s

The heading of the column in the table that represents the time passed in the vent rate test.

Mass Flow Rate, kg/s

The heading of the column in the table that represents the mass flow rate of the battery's venting gas.

Temperature, K

The heading of the column in the table that represents the temperature of the battery's venting gas.

Initial Core Part Density

The initial density of the battery cell core, prior to venting.

Apply Model Constraints

When activated, a new node Thermal Runaway Battery Vent Model > Model Activation Constraints appears. See Thermal Runaway Battery Vent Model—Model Activation Constraints.

Interpolation Type

Specifies the method that Simcenter STAR-CCM+ uses to interpolate between data values that are given in the vent rate table. Choose from:

• Linear—uses linear interpolation
• Spline (Bezier)—uses Bezier spline interpolation

Thermal Runaway Battery Vent Model > Model Activation Constraints

The model activation constraints allow you to specify one or more criteria that control the activation of the Thermal Runaway Battery Vent model. These criteria verify if a selected field variable, for example temperature, is in a given range. To determine the value of this field variable, the selected Field Function is evaluated over the Core Parts that you assign to the battery module cell using one of the Evaluation Methods that you specify.

For more information about the core parts that you assign to the battery module cell, see Battery Modules Reference: [Battery Module Cell] Core Parts.

注	Once the constraint has been met and the vent model is activated during the simulation, it cannot be deactivated.

Right-Click Actions

New

Adds a new node, Thermal Runaway Battery Vent Model > Model Activation Constraints > Model Constraint 1, which is a new model activation constraint.

Model Activation Constraints > [model constraint]

Properties

Field Function

Selects the field function that the constraint uses.

Range Operation

Selects one of two range operations to define the criterion at which the thermal runaway battery vent model activates.

• >=: When the value of the selected Field Function is greater than or equal to Value, the Thermal Runaway Battery Vent model activates.
• <=: When the value of the selected Field Function is less than or equal to Value, the Thermal Runaway Battery Vent model activates.

Value

Specifies the limiting value for the Range Operation.

Evaluation Method

Selects the method to evaluate the field variable.

• Volume Average: The specified Field Function is volume-averaged over the Core Parts that you assign to the battery module cell.
• Maximum: The maximum value of the specified Field Function is evaluated on the Core Parts that you assign to the battery module cell.

3D Battery Cells

3D battery cells geometry with the 3D RCR model are imported from Simcenter Battery Design Studio.

Battery cells that are created in Simcenter Battery Design Studio and imported from a .tbm file (or an encrypted .ebm file) have the following properties and child nodes. The details that are specified here are populated from the information in the .tbm file, however, you can edit some of the details of the battery definition as required.

[battery cell]

Right-Click Actions

Highlight

Highlights the selected battery cell in the scene.

This action works only if Highlight Parts in Scene is deactivated in the menu under Tools > Options > Visualization.

Reload...

Reloads the battery cell data from a .tbm or .ebm file. This option allows you to update the battery cell if you change the .tbm or .ebm file.

Export...

Exports the battery cell data to a .tbm or .ebm file. This option allows you to recreate a file from the battery cell information that is stored within the simulation.

You cannot choose the export format: it is the same as the format of the original file that you imported.

New

Creates a Tables > [RCR table] node for which you can specify the table parameters for a set of conditions—for example, at a set temperature and current.

See RCR Table Reference

Properties

Properties	Stacked Cell	Spiral Cell
TBM File
Unit Cell Model
Electrical Mesh Dimensions
Specified Electrical Mesh Dimensions
Actual Electrical Mesh Dimensions
Number of Spokes
Positive Post Parts
Negative Post Parts

TBM File

Displays the path to the imported .tbm file or .ebm file.

Unit Cell Model

Identifies the battery model that is defined in the .tbm file for the imported battery cell.

For empirical models, you can override the cell capacity or state of charge settings. You cannot override any settings for a battery cell that uses a physical model.

For more information, see Setting Cell Data Overrides.

Electrical Mesh Dimensions

Available for stacked cells. Defines the user-specified electrical mesh resolution—the number of mesh cells in the x, y, and z directions.

Specified Electrical Mesh Dimensions

Available for cylindrical cells. Defines the user-specified electrical mesh resolution—the number of mesh nodes in the x and y directions. The default is the mesh that is specified in the .tbm file. You can modify the mesh dimensions if necessary.

Actual Electrical Mesh Dimensions

Read-only. Defines the electrical mesh resolution that is computed from the specified layout of a spiral cell and the specified electrical mesh dimensions.

Simcenter STAR-CCM+ uses this resolution.

Number of Spokes

Available for cylindrical cells. Defines the number of spokes. Spokes are a component of the electrical mesh. You can reduce the number of spokes to speed up calculations or increase it to improve the accuracy of the model.


You can specify the number of spokes between 50-1000. 


Positive Post Parts

If you have added external posts to the battery model, this property specifies the positive post parts. You can modify the selection as necessary.

If you have not added any external posts, this property is empty.

If you want to add external post parts, click the ... button and then, in the selection dialog, select the appropriate parts.

Negative Post Parts

If you have added external posts to the battery model, this property specifies the negative post parts. You can modify the selection as necessary.

If you have not added any external posts, this property is empty.

If you want to add external post parts, click the ... button and then, in the selection dialog, select the appropriate parts.

Battery Cell > Cell Properties

Builders

Simple Builder

Available for stacked cells. Specifies how the components are placed together to make the completed cell. The simple builder specifies the orientation of the plates within the cell, the size and configuration of the stack, and any protective overwrap that is given to the electrode stack. The simple builder also specifies the offsets that the separator introduces between the electrodes and the pouch.

Detailed Builder

Available for cylindrical cells. Specifies how the components are placed together to make the completed cell.

The detailed builder specifies the orientation of the cell tabs, the winding and vertical alignment of the cell.

Models

Electrolyte

The General Electrolyte model is always specified. This model describes the behavior of the electrolyte within the cell.

IET

One IET model is specified per cell. This model describes the electronic and thermal behavior of the cell.

Simcenter STAR-CCM+ supports the NTG model, the RCR model, and the DISTNP model. Some other models that are available in Simcenter Battery Design Studio are not supported.

For more information on the IET models that are available in Simcenter Battery Design Studio, see the Simcenter Battery Design Studio Guide.

Physical Cell Description

Cell Voltage

Specifies the current state of the cell, how the lithium is distributed between the two electrodes, and the allowable voltage range of the cell.

Electrolyte

Specifies the formulation of the chemical mix that makes up the electrolyte. An electrolyte is a combination of multiple salts and solvents, and each ingredient is specified separately.

Internals

Specifies the fillers that are inserted in cell packaging alongside the active components. These items are used to provide shape and stability to the components within the packaging and are effectively inert.

Negative Electrode

Specifies the physical and thermal properties of the electrode, the formulation (the chemical substance that makes up the electrode), the tabs, and the collector that connects the electrode to the tab.

For stacked cells, the busbars are also specified. The two busbars span the cell, joining tabs together.

For cylindrical cells, the tape that connects the tab to the electrode is also specified.

For more information, see Electrode Properties.

Package

Specifies the packaging of the cell. The packaging affects the thermal performance of the cell.

Positive Electrode

As for the Negative Electrode, above.

Separators

Specifies the separator that is used to separate the various chemically reactive components within the cell to limit reaction rates.

Electrolyte Properties

Simcenter STAR-CCM+ supports the CAEBAT electrolyte property sets that are available in Simcenter Battery Design Studio. These property sets are based on a model that was developed by K. Gering and were generated as part of the Computer-Aided Engineering of Batteries (CAEBAT) program.

For more information, see Abstract #593, 224th Meeting of the Electrochemical Society: https://ecs.confex.com/ecs/224/webprogram/Abstract/Paper20427/B4-0593.pdf

For more information on the electrolyte property sets that are available in Simcenter Battery Design Studio, see the section Using Predefined Electrolyte Property Sets in the Simcenter Battery Design Studio User Guide.

Electrode Properties

For more information on the electrode properties, see the Simcenter Battery Design Studio User Guide.