Fraunhofer Institute for Transportation and Infrastructure Systems IVI
Fraunhofer Institute for Transportation and Infrastructure Systems IVI

Testing Capacities and Equipment

Test Stands for Battery Cell Characterization

The institute owns several test stands that they use to characterize battery cells, parameterize battery modules, as well as development efficient state estimators for battery state of charge (SOC), ageing (SOH), and function (SOF) for their clients. The data acquired can be used to create databases, draw comparisons between different cells and answer clients' inquiries about the suitability of individual cells for a concrete use case. In any case, the number and execution of the required test runs will be harmonized with the demands of the clients.

  • BasyTec XCTS
  • High-precision single-cell measuring station
  • Gamry Interface 1000 impedance spectrometer 
  •  Gamry FC350 impedance measuring system
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The institute owns two conventional testing systems manufactured by BasyTec for the characterization of battery cells .

Cell Test Stand Data

  • Total of 24 measuring channels
  • Voltage range of the cell under testing: 0 V - 6 V
  • Current range per channel: ±50 A
  • Prallelization of up to 6 channels possible. Sum current: 300 A

Achievable Testing Conditions

  • Characteristics of the climate chamber:
  • Temperature range: -40 °C - 100 °C
  • Range of humidity: 10 % - 95 % relative humidity
  • Volume of testing space: 600 l
  • Integration of temperature profiles with variations of up to 3 K/min
  • Realization of standard driving cycles, customer-specific load cycles and pulse tests

Measuring Equipment and Test Stand Automation

  • Precision of voltage measurement: 1 mV
  • Precision of current measurement: 50 mA
  • Precision of temperature measurement: 0.2 K
  • Testing process implemented in BasyTest Software

There is a separate measuring station for the detailed investigation of single cells and the parameterization of cell models. The station has high-precision measuring equipment and can be individually adapted to customer demands in all relevant aspects (measuring technology, testing process, etc.).

Cell Test Stand Data

  • 1 channel
  • Voltage:
    • Range: 0 V - 5 V
    • Resolution: 0.25 mV
    • Precision: ±0.05 %
  • Current:
    • Range: -500 A - 250 A
    • Resolution: 25 mA
    • Precision: 0.05 %

Achievable Testing Conditions

  • Characteristics of the climate chamber:
    • Temperature range: -20 °C to 80 °C (±0.5 °C consistency)
    • Range of humidity: 40 % to 96 % relative humidity (±4 % consistency)
    • Testing space volume: 545 x 600 x 400 mm (W x H x D)
  • Integration of temperature profiles
  • Realization of standard driving cycles, customer-specific load cycles, pulse tests
  • Integration of control strategies (depending on measurement values) and complex algorithms such as state estimation

Measuring Equipment and Test Stand Automation

  • Voltage measurement (absolute precision of 0.5 mV @ 5 V)
  • Current measurement (absolute precision of 50 mA @ 500 A)
  • Temperature measurement (absolute precision of 0.2 K)
  • Recording of measuring data via NI measuring system (64 AI channels, 8 AO channels)
  • Testing process implemented in Matlab/Simulink for maximum freedom regarding the design of test plans, control via DSpace Autobox

In the past years, impedance spectroscopy has gained increasing importance as a method for cell state determination. In addition to electrochemical characterization of a battery cell, electrical modeling of cells is also possible depending on their state using impedance spectrum evaluation.

The institute owns a Gamry Interface 1000 device for galvanostatic und potentiostatic impedance spectroscopy.

Measuring Device Data

  • 1 channel
  • Excitation frequency: 10 µHz – 1 MHz
  • Current excitation: ± 1 A (galvanostatic)
  • Voltage excitation: ± 12 V (potentiostatic)

Achievable Testing Conditions

  • Characteristics of the climate chamber:
    • Temperature range: -40 °C to 100 °C
    • Range of humidity: 10 % to 95 % relative humidity
    • Testing space volume: 600 l
  • Integration of temperature profiles with variations of up to 3 K/min

Measuring Equipment and Test Stand Automation

  • Precision of voltage measurement: 1 mV
  • Precision of current measurement: 5 pA
  • Precision of temperature measurement: 0.2 K
  • Testing process almost fully automatable

The measuring of impedance values during the charging and discharging process of battery cells is especially relevant for traction applications. Using the Gamry FC350, electric sources and sinks that supply battery cells with power or take power from it can be controlled so that they a variable AC signal is modeled onto a DC signal. By measuring the cells' voltage responses, the impedance can be inferred.

Measuring Device Data

  • 1 channel
  • Excitation frequency: 10 µHz to 5 kHz
  • Current excitation: ± 120 A

Achievable Testing Conditions

  • Characteristics of the climate chamber:
    • Temperature range: -40 °C – 100 °C
    • Range of humidity: 10 % – 95 % relative humidity
    • Testing space volume: 600 l
  • Integration of temperature profiles with variations of up to 3 K/min