Electric Mobility Test Rigs

The electric mobility research group operates two test rigs which have been substantially extended or built up within the project "XiL-BW-e - Frameworkbasiertes XiL-Labornetzwerk BW für Elektromobilität" (XiL-BW-e - framework-based XiL laboratory network Baden-Württemberg for electric mobility), which has been funded by the Ministery of Science, Research and the Arts of Baden-Württemberg.

Contact

Dr.-Ing. Michael Buchholz
Room: 41.2.219
Phone: +49 (0)731 50 27003
E-mail | Homepage

Battery Cell Test Rig

The battery cell test rig comprises a temperature chamber, power electronics with integrated measurement instrumentation to test the battery cells, a test rig safety guard as well as a real-time rapid-prototyping control-unit to prove developed algorithms and, at the same time, control the test rig. The temperature chamber allows testing of battery cells under varying operation conditions and provides the required housing with safety equipment for the tests. The actual cell tester with power electronics and measurement instrumentation has 6 individual channels, which can be operated separately or in parallel connection. Additionally, the instrumentation directly allows for electrochemical impedance spectroscopy (EIS). An independent safety guard for the test rig ensures safety during testing.

The test rig has two different control modes: On the one hand, the standard software of the manufacturer is available. Alternatively, the test rig is fully controllable by a free programmable real-time rapid-prototyping control unit. This, on the other hand, allows for integration of algorithms under development for a direct validation during measuring. The real-time control unit additionally allows the networked operation of the test rig with other test facilities within the laboratory network XiL-BW-e.

The battery cell test rig has the following technical characteristics:

  • Battery cell tester SL6/300/1.8BT6C by ScienLab with 6 channels
    • Voltage range: 0 – 6 V
    • Current range per channel: ±300 A
    • Parallel connection of 2 – 6 channels for higher overall currents
    • Impedance spectroscopy: up to 5 A within frequency range 100 mHz to 5 kHz
  • Temperature chamber VTS³ by Vötsch
    • Volume of testing chamber: 600 liters
    • Temperature range: -72°C – 80°C
    • Temperature change rate: up to ±6 K/min
  • Real-time control unit MicroLabBox by dSPACE
    • Sample time of real-time control: 1 ms
    • 1 free processor for algorithms under test
    • Additional IOs for further measurements
    • Interface for networked operation with other test benches

If you are interested in our test rig, a detailed specification is available upon request.

Picture of the battery cell test rig
Battery cell test rig
Detailed Picture of a battery cell inside the testing chamber
Battery cell in testing chamber
Detailed picture of the cell tester
Detailed view on the cell tester

Electric Power Train Test Rig

The electric power train test rig comprises two induction machines with corresponding power electronics and measurement instrumentation for the output side of the power train, a cooling unit for the equipment under test, a battery simulator, a test rig control unit and a residual vehicle simulation unit. The induction motors emulate the wheel forces due to driving resistances or mechanical braking at the propelled axis of the vehicle. They are mounted on a machine bed which also holds the electric power train components. Using the cooling unit , these power train components under test (electric motor, mechanical transmission, inverter) can be tempered with usual automotive coolants according to the testing and operating requirements. The battery simulator operates model-based and emulates the behavior of a desired traction battery in real-time, supplying the electric power train under test with energy.

Control of the overall test rig as well as a central data logging are realized by a free programmable real-time control unit (rapid-prototyping system). This control unit is additionally connected to an elaborated real-time simulation of the residual vehicle and it's environment, allowing for realistic testing scenarios with arbitrary driving cycles and vehicle parametrization. The real-time control unit accordingly operates the power train as well as the induction motors and additionally allows for a networked operation with the Battery Cell Test Rig or other test facilities within the laboratory network XiL-BW-e.

Due to the fact that a research focus is laid on vehicle operating strategies and realistic ageing of battery cells (by a networked operation of both test rigs), a standard electric power train similar to that of a Smart Electric Drive is available. This comprises a permanently excited synchronous motor, a dedicated automotive inverter, as well as a transmission including differential. The required residual bus simulation for the electronic components is supplied by the real-time control unit of the test rif via CAN.

The technical characteristics of the electric power train test rig are the following:

  • Induction motors by Siemens for wheel emulation:
    • Speed range: 0-2000 1/min
    • Maximum torque  per motor: 1970 Nm
    • Power per motor: 75 kW nominal /150 kW peak
    • Torque logging by additional torque measurement hubs
  • Battery simulator by ARADEX
    • Voltage range: up to 600V
    • Output power: 160 kW
    • Direct integration of real-time battery models within the simulator control or supervisory control by test rig control unit
  • Residual vehicle and environment simulation CarMaker by IPG
    • Real-time simulation of the vehicle behavior and the driving cycle
    • Simulation of different power train topologies (e.g. pure electric or hybrid)
    • Visualization of driving behavior
  • Real-time control unit MicroLabBox by dSPACE
    • Sample time of real-time control: 1 to 10 ms (depending on subsystem)
    • Integration of complex battery models and direct control of the power electronics of the battery simulator
    • Interface for networked operation with other test rigs
  • Electric power train similar to Smart Electric Drive
    • Permanently excited synchronous motor SMG180/120 by BOSCH (90 kW power and up to 12.800 1/min speed) with dedicated inverter
    • Original transmission including differential of a Smart Electric Drive by Getrag with a fixed overall transmission ration of 1:10

If you are interested in our test rig, a detailed specification is available upon request.

Picture of the electric power train test rig
Electric power train test rig
Detailed picture of the motor testee
Detailed view on the electric motor testee
Topview on the power train on the test rig
Power train on test rig
Detailed picture of output induction machine with torque measurement hub
Output induction machine with torque measurement hub

Networked Operation

The real-time control units of the two test rigs allow for a networked operation. This coupling is signal-based and enables measurements for ageing of battery cells with real electric loads from a power train. These "wheel to cell" investigations can help for an early evaluation of new battery cells with real loads including fluctuations and/or stochastic effects occurring in reality, which usually are not (or even cannot) be modelled. The other way round, the battery cell behavior is then scaled up to a full battery and  applied to the power train by the battery simulator. Thus, also effects on the power train, e.g. resulting from voltage drop at high loads on a real cell, can be investigated in this assemblage.

In addition to this networked operation of the two locally available test rigs, a networked operation with further test facilities in other research institutions in Baden-Württemberg is available via the laboratory network XiL-BW-e. Exemplary networked testing scenarios are the ageing of battery cells with respect to (dynamic) inductive charging or the behavior of other components in dependence on the battery cell behavior. Further information on the laboratory network can be found on the website  www.xil-bw-e.de. Also, more detailed information is available upon request.

Picture of electric power train test rig and battery cell test rig
Networked operation of electric power train test rig and battery cell test rig
XiL-BW-e logo
Laboratory network XiL-BW-e