Store all DUTs in the Device_under_Test_Library.

The database structure for the battery application corresponds to the structure of the modular application as described in the PAtools User Manual.

General Structure of the DUT Library

Each DUT contains organizational and technical data.

Figure 22. General Structure of the DUT Library


In PAconfigurator, a DUT is always classified as a cell, a module, or a pack.

Folders in PAconfigurator contain the following information about a DUT.

  • The configuration part. The configuration part includes organizational data and technical battery data.
    • Use organizational data to classify and to structure the measurement data. Organizational data can be different depending on your application.
    • The technical data contains all relevant information required for the operation of the DUT.
  • A folder named General. For battery module applications, the General folder contains a table in which you enter voltage measurement signals. For battery pack applications, the General folder contains a restbus simulation.

Organizational Data

The organizational data of a DUT contains the following information:

  • Manufacturer
  • Model
  • Serial number
  • Technology, e.g., LiFePo4
  • Vehicle project

The implementation of the data is provided by the initialization of variables group type.

Technical Data

The technical data contains all relevant information required for the operation of the DUT.

Operating Limits (Switchable, Static)

The cell, module, or battery pack operating limits are implemented as switchable static limit values. Limits refer to the following data:

  • Voltage limit of a module or a pack, which is available in module applications or pack applications
  • Voltage limit of a cell, which is available in cell, module, or pack applications
  • Current limit
  • Power limit
  • Temperature limit

All limits are upper and lower limits. Static in this case means that the limits are state dependent. You must store several parameter sets for different test steps when the limits of the battery are deliberately violated to test fault reactions. Another scenario could be a capacity test.

This data is located and parameterized in the table DUT<application>_LimitsParaSet.STB, where application is either cell, module, or pack.

The maximum and minimum values represent the setpoint limitation. Therefore, these limits are still in permissible operation.

Calculating the BattPack_Voltage_Ctrl.MAX/MIN

Refer to the following variable reference when performing calculations.

Table 35. Variable Reference for Battery Pack Voltage Calculations
Variable Description
Vmin Minimum cell voltage
Vmax Maximum cell voltage
Vmean Average cell voltage
Vmin diff Voltage difference between the minimum cell voltage and the mean cell voltage
Vmax diff Voltage difference between the maximum cell voltage and the mean cell voltage
VSP Cell voltage setpoint
VSP ctrl min Corrected minimum cell voltage setpoint
VSP ctrl max Corrected maximum cell voltage setpoint
VBatt SP ctrl min Minimum battery voltage setpoint
VBatt SP ctrl max Maximum battery voltage setpoint
CellsSerial Number of cells in a series
VCell diff max Maximum cell voltage difference
Table 36. Calculations for the Battery Pack Voltage
Equation Calculation Description
V m i n   d i f f = a b s V m i n - V m e a n
Voltage difference between the minimum cell voltage and the mean cell voltage
V m a x   d i f f = a b s V m a x - V m e a n
Voltage difference between the maximum cell voltage and the mean cell voltage
V S P   c t r l   m i n = V S P + V m i n   d i f f
Corrected minimum cell voltage setpoint
V S P   c t r l   m a x = V S P + V m a x   d i f f
Corrected maximum cell voltage setpoint
V B a t t   S P   c t r l   m i n = V c t r l   m i n × C e l l s S e r i a l
Minimum battery voltage setpoint
V B a t t   S P   c t r l   m a x = V c t r l   m a x × C e l l s S e r i a l
Maximum battery voltage setpoint
V C e l l   d i f f   m a x = a b s V S P   c t r l   m a x - V S P   c t r l   m i n
Continuous calculation of the difference during the CV step
Note VBatt SP ctrl min and VBatt SP ctrl max are sent to the cycler as setpoints.
Calculating the Mean Voltage

To calculate the mean voltage, divide the total voltage by the number of serial cells. The following measurement values are available for the total voltage:

  • The value of the sense measurement of the cycler
  • The sum of the measured individual voltages from the battery management system (BMS) or measuring trolley

Although both values display the total voltage of the battery, the values are not identical. Different measuring devices can cause a deviation in value.

For example:

V B M S = 33 . 123   V

V C y c l e r = 33 . 176   V

O f f s e t = a b s 53   m V

The offset value is determined at the start of the test and remains constant during the test. Therefore, use the following equations to calculate Vmean:

V o f f = V s e n s e - V B M S

V m e a n = V B M S + V o f f C e l l s s e r i a l

Control Parameter

The implementation for the necessary control parameter is provided by the group Batt<application>_Cycler_controlParameterSet.SP, where application is either cell, module, or pack.

The number entered for the parameter set of the cycler is used on the test station. The variable should be mapped into the module of the cycler.

Tolerances for Test Station Shutdown

The test station shuts down when the implemented static switch-off limits are exceeded. The switch-off limits are not specified as fixed quantities, but relative to the maximum and minimum operating limits.

The implementation is provided by the group Tolerances_for_Test_Bench_Shutdown.

Other Technical Parameters

You can adjust the following settings for your DUT as described below.

DUT Data

The specification of the nominal battery capacity and the C-rate are important for testing. Together, the specifications form the nominal charge and the nominal discharge current.

You can also specify whether the battery application is for BEV or PHEV.

These parameters are located in the following groups (of group type initialization of variables) for your application.

  • Cell: DUTCellData
  • Module: DUTModuleData
  • Pack: DUTPackData

DUT Current Maximum Limiter

The table DUT_Current_Max_Limiter_SOC_Temperature.WTB shows the maximum currents for different states of charge (SOC) and temperatures of a battery. Use this table to parameterize a maximum set current for the cell given a certain temperature and a certain SOC.

The first row contains the temperature values. The first column contains the SOC values. If a battery has values that are in an intermediate range, then the system calculates the maximum current using four-point interpolation.

DUT Current Minimum Limiter

The table DUT_Current_Min_Limiter_SOC_Temperature.WTB shows the minimum currents for different states of charge (SOC) and temperatures of a battery. Use this table to parameterize a minimum set current for the cell given a certain temperature and a certain SOC.

The first row contains the temperature values. The first column contains the SOC values. If a battery has values that are in an intermediate range, then the system calculates the minimum current using four-point interpolation.

DUT SOC Open Circuit Voltage Curve

In the table DUT_SOC_OCV_curve.WTB, you can enter SOC and related voltage values. You can also compare the values with the calculated values from the BMS.

Temperature Sensor Difference (Pack/Module/Cell Applications)

Place temperature sensor signals in the DUT[Pack/Module/Cell]_Tcells.TAB table.

The system monitors temperature sensor signals for the following conditions:

  • Invalid values.
  • Maximum difference between the maximum and minimum signal values.

Both conditions result in a warning in PAcontroller. You can specify both conditions by editing DUT[Pack/Module/Cell]_Miscellaneous.

For example, you can use DUT[Pack/Module/Cell]_Miscellaneous to set the maximum temperature difference between sensors to 5 ℃. In this case, if sensor 1 displays 25 ℃ and sensor 2 displays 31 ℃, PAcontroller would display an error. The temperature difference is greater than 5 ℃.

Mapping Cell Temperatures

The DUTCell_Tcell.TAB table maps to the VCellCTRL module within VCellCTRL_Tcells.TAB. You can input as many temperatures into the DUTCell_Tcell.TAB table as there are rows.

The VCellCTRL module evaluates the DUTCell_TCell.TAB table and calculates the following values:

  • VCellCTRL_Temperature_Sensors_Mean.CV—The mean temperature.
  • VCellCTRL_Temperature_Sensors_MIN_MAX_Diff.CV—The difference between the minimum and the maximum temperatures.

    • Map cell temperatures in PAconfigurator.

    1. In DUTCell_Tcell.TAB, define a row for each temperature sensor.
    2. In VCellsCTRL_Mapping_TAB.IN, select DUTCell_Tcells.TAB as the Source and VCellCTRL_Tcells.TAB as the Destination.
      The mean temperature and the temperature difference map to the BattCell application in the VCellCTRL_Mapping.Out table.
    3. Optional: Add a row to the VCellCTRL_Mapping.Out table to map an additional variable to Battcell_DUT_Temp.AV.
      For example, you can map VCellCTRL_Temperature_Sensors_Mean.CV or DUTCell_Temperature_Sensor_4.MV to Battcell_DUT_Temp.AV.
    You can map battery pack and battery module DUTs using the same process and applicable tables.

    Cell Voltage Difference (Module/Pack Applications Only)

    This group shows how high the allowed voltage difference is between the minimum and maximum voltage of the cells. If the allowed difference is exceeded, the system triggers a soft stop.

    BattModule Measurements (Module Applications Only)

    You can set the way the voltage is measured at the cells. You can use an additional measurement technique. Otherwise, the system uses the value from the DC cycler.

    If you use an additional measurement technique, you can enter the measurement signals or the standard PAtools variables into the step table DUTModule_Vcells.WTB. The table is in the system part of DUTModule.

    Pack Connectors Limits (Pack Applications Only)

    For multiple battery connections, you can limit the current for each connection in this group.

    BMS SOC Source (Pack Applications Only)

    The BMS SOC Source group is where you can select where the battery state of charge (SOC) information comes from.

    The following options are available:

    • From the BMS of the battery
    • Through the calculation in the standard cycle

    Rest Bus Simulation (Pack Applications Only)

    An example of a battery rest bus simulation is available in the following database directory: <\PAcfg\Device_under_Test_Library\BattPack_1_Connector\ DUTPack_Template\General\BMS-CAN>.

    Note This example does not represent communication to a real DUT, but it is based on it.