SiCWell Dataset

Citation Author(s):
Daniel
Weber
Marius
Gentejohann
Erik
Goldammer
Michael
Schlüter
Submitted by:
Daniel Weber
Last updated:
Mon, 11/08/2021 - 05:19
DOI:
10.21227/mnmw-8c42
Data Format:
License:
0
0 ratings - Please login to submit your rating.

Abstract 

The SiCWell Dataset contains data of battery electric vehicle lithium-ion batteries for modeling and diagnosis purposes. In this experiment, automotive-grade lithium-ion pouch bag cells are cycled with current profiles plausible for electric vehicles. 

The analysis of current ripples in electric vehicles and the corresponding aging experiments of the battery cells result in a dataset, which is composed of the following parts: 

 

  • Vehicle and drive train parameters: The parameters of a vehicle and drivetrain model for simulation of current profiles.
  • Current profiles of two reference driving cycles: The DC and AC current profiles of the sWLTC and UDDS driving cycles for a simulated electric vehicle. 
  • Calendar tests: Periodic checkups of battery cells that are stored at a fixed ambient temperature.
  • Sinusoidal and dc tests: Measurements and checkups of battery cells that are cycled with a dc current with a superimposed sinusoidal current.
  • Artificial ripple tests: Measurements and checkups of battery cells that are cycled with a dc current with varying superimposed ripple currents.
  • Realistic ripple tests: Measurements and checkups of battery cells that are cycled with current profiles of realistic driving profiles of a simulated electric vehicle.

 

Those parts are grouped in their potential application and can be downloaded separately. For every component of the dataset, there is a jupyter notebook that demonstrates data access examples. More information about the creation of the dataset can be found at [1].

Instructions: 

Cell Aging Scenarios

The battery cells are cycled in groups of three cells in series. The scenarios for each cell are the following:

  • Ka01, Ka02: Calendar test 35°C 80% SoC
  • Ka03, Ka04: Calendar test 35°C 45% SoC
  • Ka05, Ka06: Calendar test 45°C 80% SoC
  • Ka07, Ka08: Calendar test 45°C 20% SoC
  • Ka09, Ka10: Calendar test 45°C 45% SoC
  • Ka11, Ka12: Calendar test 45°C 60% SoC
  • DC01, DC02, DC03: DC cycling
  • AC01, AC02, AC03: Sinusoidal cycling 10 kHz, 12.5 A
  • AC04, AC05, AC06: Sinusoidal cycling 10 kHz, 25.0 A
  • AC07, AC08, AC09: Sinusoidal cycling 10 kHz, 6.25 A
  • AC10, AC11, AC12: Sinusoidal cycling 40 kHz, 12.5 A
  • AC13, AC14, AC15: Sinusoidal cycling 20 kHz, 12.5 A
  • AC16, AC17, AC18: Sinusoidal cycling 40 kHz, 6.25 A
  • AC19, AC20, AC21: Artificial ripple cycling
  • AC22, AC23, AC24: Realistic ripple cycling
  • AC25, AC26, AC27: Realistic ripple cycling

Current Ripple Evaluation

The evaluation results of current ripples in a battery-electric vehicle are stored in the “current_ripple_evaluation” directory. It contains the following files:

  • input_sWLTP.csv/input_UDDS.csv: The speed, torque, and power of the sWLTP and UDDS cycles at every second of the simulated battery-electric vehicle.
  • cycler_sWLTP.csv/cycler_UDDS.csv: The compressed current values for every second of the sWLTP and UDDS cycles. More details about the compression can be found at [1].
  • parameters.csv: The parameters for simulation of the battery-electric vehicle and the drivetrain.
  • sWLTP.h5/UDDS.h5: The simulated current and voltage of the battery-electric vehicle in the time-domain sampled with 500 kHz. Every second has its operating point, which is simulated for a second.

 

Cell Cycles

The raw current, voltage, and temperature measurements of the cycled battery cells. The results are stored in the “cell_cycling_*” directory with the following files:

 

  • cell_cycling_sinusoidal/[cell id]/[cell id]_cycle[cycle id].hdf5: The raw measurements of the sinusoidal cycling experiments.
  • cell_cycling_artificial_ripple/[cell id]/[cell id]_cycle[cycle id].hdf5: The raw measurements of the artifical ripple cycling experiments.
  • cell_cycling_realistic_ripple/[cell id]/[cell id]_cycle[cycle id].hdf5: The raw measurements of the realistic ripple cycling experiments.

The measurements have been taken periodically by an external 2MHz measurement system. Each .hdf5 file contains the measurements of a specific cycle number of the experiment. In the sinusoidal and artificial ripple tests, a measurement has been taken for every 1 % State-of-Charge. In the realistic ripple tests, a measurement has been taken every 5 seconds. Every measurement has a duration of 100 ms and a sampling rate of 2 MS/s.

Each measurement is a group in the hdf5 file, with the voltage and current as 1d 32bit floating-point arrays. Each measurement also has a Unix UTC timestamp of the time of the measurement, the cell temperature, capacity, and resistance[10s] stored as attributes. The capacity and resistance are synchronized with the checkups and interpolated linearly over the number of cycles.

 

Cell Checkups

The periodic checkups of the battery cells are composed of capacity, internal resistance, EIS, OCV, and qOCV measurements. Measurements that take longer, such as EIS and OCV, are not taken at every checkup. The results are stored in the “cell_checkups” directory with the following files:

 

  • Overview.csv: List of every checkup of every battery cell. For every checkup, the date, number of cycles, capacity, 10s resistance, and references to the more detailed checkup files are stored.
  • EIS/[cell id]_CheckUp[checkup id]_[date]_EIS.csv: The results of the electrochemical impedance spectroscopy from 0.001 to 50,000 Hz using an EIS-meter.
  • OCV/[cell id]_CheckUp[checkup id]_[date]_OCV.csv: Results of the open-circuit voltage measurement between 0 and 100 % State of Charge in 5 % steps.
  • qOCV/[cell id]_CheckUp[checkup id]_[date]_qOCV.csv: Results of the quasi-open-circuit voltage measurement between 0 and 100 % State of Charge in 1 % steps. It contains the quasi-open-circuit voltage, 1s resistance, and 10s resistance.
  • OCV_raw/[cell id]_CheckUp[checkup id]_[date]_OCV_raw.csv: Raw current, voltage, and temperature values of the OCV measurement.
  • qOCV_raw/[cell id]_CheckUp[checkup id]_[date]_qOCV_raw.csv: Raw current, voltage, and temperature values of the qOCV measurement.
  • Capacity_raw/[cell id]_CheckUp[checkup id]_[date]_Cap_raw.csv: Raw current, voltage, and temperature values of the capacity measurement.