RCR Table Reference

In an RCR table, each set of Vo, Ro, Rp, and tau parameters are functions of the state of charge (SOC) for a particular temperature. The evolution of each parameter is specified as a column within the RCR table.

RCR Table

Equivalent Circuit Battery Cell > RCR Equivalent Circuit Model > Parameter Tables > [RCR table]

Properties

Table

Allows you to select a previously-imported RCR table that is stored within the Tools > Tables node. When Enable Auto-fill Table Parameters is activated, the table that you select is parsed according to the rules defined here and the table parameters are extracted and auto-filled appropriately.

The following image describes how Simcenter STAR-CCM+ Batteries represents the RCR table data.

It is also possible to manually assign specific RCR table column headings for each property in the GUI.

When Simcenter STAR-CCM+ Batteries identifies data for Rp and Tau in the RCR table that is selected, Rp[n], Tau[n] sub-nodes appear under the RCR table node.

Temperature

Temperature at which the table parameters are specified.

Charge/Discharge Type

Charge: specifies that the table data applies when the cell is charging.

Both: specifies that the table data applies when the cell is either charging or discharging.

Discharge: specifies that the table data applies when the cell is discharging.

Charge Current

The current through the cell when it is charging.

Discharge Current

The current through the cell when it is discharging.

Ro, Ohm

The heading of the column in the table that represents the open circuit series resistance Ro (ohm m^2).

SOC [0-1]

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.

Vo, Volts

The heading of the column in the table that represents the open circuit voltage (volts). Simcenter STAR-CCM+ interpolates the data using monotonic cubic interpolation.

Ro Interpolation Type

Specify the method that Simcenter STAR-CCM+ uses to interpolate between data values that are given for the open circuit series resistance Ro at specific temperatures in the table. Choose from:

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

Vo Interpolation Type

Specify the method that Simcenter STAR-CCM+ uses to interpolate between data values that are given for the open circuit voltage Vo at specific temperatures in the table. Choose from:

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

Enable Auto-fill Table Parameters

When activated, the table properties are auto-populated upon selecting the RCR table, based upon the values in the selected table.

For details about the search criteria that Simcenter STAR-CCM+ uses to search for each parameter, see RCR Table Reference.

Right-Click Actions

Tabulate: Displays the RCR table data in a pop-out Tabular Data window which allows you to export and save the tabular data as a .csv file.
Plot RCR Tables: Available after importing RCR Tables. Plots are created to display the selected RCR Table data. For example:

This action automatically opens all the plots in a layout which can be viewed under the Layout Views node. Below is an example of the layout of the plots.
Delete: Deletes the RCR table.

Equivalent Circuit Battery Cell > RCR Equivalent Circuit Model > Parameter Tables > [RCR table] > Rp[n], Tau[n]

When Simcenter STAR-CCM+ Batteries identifies data for Rp and Tau in the RCR table that is selected, Rp[n], Tau[n] sub-nodes appear under the RCR table node.

Table

Read-only property that identifies the RCR table from which these parameters were extracted.

When Enable Auto-fill Table Parameters is activated for the RCR table, the table data is parsed according to the rules defined here and the Rp and Tau parameters are extracted and auto-filled appropriately.

Rp, Ohm

The heading of the column in the selected RCR table that represents the polarization resistance Rp parameter (ohm m^2).

Tau, s

The heading of the column in the selected RCR table that represents the time constant Tau parameter (s).

Rp Interpolation Type

Specify the method that Simcenter STAR-CCM+ uses to interpolate between data values that are given for Rp[n] at specific temperatures in the table. Choose from:

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

Tau Interpolation Type

Specify the method that Simcenter STAR-CCM+ uses to interpolate between data values that are given for Tau[n] at specific temperatures in the table. Choose from:

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

RCR Table Requirements

The RCR Table model requires you to provide the appropriate data for each given temperature in a table format. You can provide different data values for charge and discharge. For each given temperature, you can also provide data tables for specific values of maximum charge current and maximum discharge current. Simcenter STAR-CCM+ Batteries requires that the following units are used for RCR table data:


RCR Table Data Parameters	Units Required in Simcenter STAR-CCM+ Batteries
$S O C$	[0-1]
$V$	Volts
$R_{o}$	Ohms
$R_{p}$	Ohms
$T a u$	Seconds

The RCR table data can be taken from either:

A .csv File: When importing RCR table data from .csv files with the Enable Auto-fill Table Parameters property activated for the table, Simcenter STAR-CCM+ Batteries parses the data that is available and selects the appropriate column of data for each parameter according to the column heading priorities that are listed in the section below.
The text in the column headings is not case-sensitive.
A .tbm File: Simcenter STAR-CCM+ Batteries interprets the data from the .tbm file and creates a series of .csv files with which it populates the RCR table properties in the GUI.; For further details about RCR table data from .tbm files, see RCR Table Values Imported From .tbm Files.
A File Directory: When importing RCR table data from an Amesim file directory, Simcenter STAR-CCM+ Batteries parses the files in the directory then creates data tables and RCR parameter tables. Data tables appear under the Tools > Tables > [directory name] node. RCR parameter tables appear under the Battery Cells > Equivalent Circuit Battery Cell > RCR Equivalent Circuit Model > Parameter Tables node.; See Parsing and Importing from Amesim File Directories.

RCR Table Column Heading Priorities

When Simcenter STAR-CCM+ Batteries interprets data from .tbm files, the column headings are given the following priority:

SOC

SOC
State of Charge (words optionally separated by a space, hyphen, or underscore)
For example: State of Charge, State_of_Charge,State-of-Charge, or StateofCharge.

Voltage

Vo
V
V0
Open Circuit Voltage (words optionally separated by a space, hyphen, or underscore).
For example: Open Circuit Voltage, Open_Circuit_Voltage, Open-Circuit-Voltage, or OpenCircuitVoltage.
Begins with Volt.
Begins with V.

Ro

Rp

Rp<index> - Rp0, Rp1, ..
Rp_<index> - Rp_0, Rp_1, ..
Rp

Tau

Tau<index> - Tau0, Tau1, ..
Tau_<index> - Tau_0, Tau_1, ..
Tau

Parsing and Importing from Amesim File Directories

Data Files and Formats

Simcenter STAR-CCM+ Batteries parses the files in the directory looking for the following file types:


File Type	Details and Format
model_information.txt	Contains general values for the battery model such as capacity, faradic efficiency, state of charge variation, mass, convection surface, specific heat, convective heat exchange coefficient, and number of RC circuits.
ro_cha.data	T3D format. Units = Ohm. Contains values for percentage state of charge, current, and temperature. If given, should be accompanied with ocv_cha.data.
ro_dch.data	T3D format. Units = Ohm. Contains values for percentage state of charge, current, and temperature. If given, should be accompanied with ocv_dch.data.
ocv_cha.data	1D format. Units = V Contains values for open circuit voltage and percentage state of charge at a given temperature. If given, should be accompanied with ocv_dch.data
ocv_dch.data	1D format. Units = V Contains values for open circuit voltage and percentage state of charge at a given temperature.
dUdT.data	1D format. Units = V/K. Optional—useful when adjusting the open circuit voltage (OCV) for the temperature.
Cdiff_<1…n>.data	T3D format. Units = F. Contains values for percentage state of charge, current, and temperature. (n = number of RC circuits—provided in model_information.txt)
Rdiff_<1…n>.data	T3D format. Units = Ohm. Contains values for percentage state of charge, current, and temperature. (n = number of RC circuits—provided in model_information.txt)

Importing Data

Simcenter STAR-CCM+ Batteries requires that all parameters (V, Ro, Rp0, and Tau0) are available at each state of charge (SOC) value.


Simcenter STAR-CCM+ Batteries parameter nomenclature	Equivalent nomenclature in Amesim
Rp<index>	Rdiff<index>
Tau<index>	Rdiff<index>*Cdiff<index>

Simcenter STAR-CCM+ Batteries performs the following process:


Reads temperatures, and then for each temperature:
	Reads currents, and then for each current:
		Reads SOCs from the corresponding ocv_cha.data/ocv_dch.data file, and then for each SOC: Adjusts OCV for temperature using dUdT.data, if provided. Interpolates Ro for the same SOC—if out of bounds, Simcenter STAR-CCM+ Batteries chooses the extremum (no extrapolation). Interpolates Rdiff and Cdiff for the same temperature, current, and SOC using the interpolation method that is described below. If the exact current data is not available, Simcenter STAR-CCM+ Batteries interpolates for the two closest available currents followed by interpolation for the given current.

Interpolation Method

When interpolating data, Simcenter STAR-CCM+ Batteries performs linear interpolation and does not extrapolate values above or below the maximum or minimum SOC values. For example, when considering the following data:


SOC	Ro
12.000985	0.076649
16.502705	0.071710
25.681674	0.063144
34.860658	0.059934
44.128070	0.058357
53.218676	0.057612
62.397622	0.057478
71.576072	0.056709
80.790474	0.054943
89.929307	0.061453
94.587454	0.065377

For SOC 50.3053, the interpolated Ro value is 0.057851.
For SOC 11, the interpolated Ro value is 0.076649.
For SOC 99, the interpolated Ro value is 0.065377.