Measurement Dataset of Thermal Fault Emulation of a 46Ah High-Power Kokam Nano Pouch Cell via Uniform and Local Heating

Preface

This dataset contains experimental data that supplement the article Thermal fault detection by changes in electrical behaviour in lithium-ion cells (10.1016/j.jpowsour.2021.229572) in the Journal of Power Sources. This dataset extends the already published cell characteristics (see 10.17632/g443f7cn7p.2) by all measured quantities associated with the conducted study. Therefore, the dataset includes sensor readings that have not been described in the before mentioned documents due to space limitations.

The published data belongs to the master thesis Development of a model-based method for the early detection of safety-critical heating of lithium-ion cells (transl.), Klink (2020), TU Clausthal that is connected to a study thankfully funded by the European Automobile Manufacturers' Association (ACEA).

Structure

The repository is subdivided in four directories (.zip) based on the content. Within these directories, the individual datasets can be found. While every dataset contains three different file types, the corresponding files can be identified based on the identical filenames. The following file types are provided:

File type
Content
Comment

*.png
Simple graph of the provided data.
Missing values are interpolated.

*.csv
Tabular data of the dataset.
Columns are separated by ";", the decimal point is ".".

*.pickle
Pickled object of a pandas dataframe (Python) of the data. Preserve index and data types.
Pickled with pandas version 2.2.2 using the pickle protocol 5

The index and column names of the tabular time series have the following name scheme: X_Y_Z 

Placeholder
Description
Example

X
Quantity symbol
U for voltage, I for current

Y
[optional] Additional index
meas for measured quantities

Z
Unit
s for seconds, V for volt

Content

The dataset contains the data of both experiments for validation and for investigation of the fault characteristics of the conducted thermal abuse test. While the electrical quantities have been recorded using a battery test stand from Keysight/Scienlab (SL60/200/12BT4C) the temperature readings have been measured by type K thermocouples and recorded with data logger from PCE instruments. For all tests, the temperature sample rate has been set to 1 Hz. Please refer to the attached schematics in SensorPositions.zip for the placement of the individual thermocouples. In addition, T_5 represents the surrounding and T_2 is on the backside of T_1. The sensor positions T_7 and T_8 are added only for the uniform heating where T_7 is located between heating element and cell and T_8 central at the heating plate. Within the referenced article, only T_1 has been used. 

For details on the experimental setup, please refer to the method section of the linked article. 

1. Validation

Description

The data contains the electrical load of the cell with an extended WLTC driving cycle that has been scaled to approx. 400 A as well as the corresponding temperature at T_1. The test was conducted within a climatic chamber at 20°C. This data can be used to either parameterize a model of the cell or to validate a model based on other parameter such as the linked parameter set.

Columns
t_s
Test time in seconds

I_meas_A
Applied current for WLTC emulation

U_meas_V
Voltage response of cell

T_meas_C
Cell surface temperature

2. ThermalCalibration

Description

For each heating setup (uniform, local) this directory contains one data set. Within this experiment, the cell was pulsed with short high current (150 A) pulses to achieve a constant thermal heating power without changing the SOC. Based on the temperature response, a thermal model can be parameterized for both heating setups. Please note, that the electrical sample rate was higher and no interpolation was conducted. 

Columns
t_s
Test time in seconds

I_meas_A
Applied current

U_meas_V
Voltage response of cell

T_?_C
Temperature reading of sensor ?. See above for description of the individual sensor positions. 

3. UniformThermalFault

Description

During cycling the cell with a continuous WLTC cycle, the thermal fault was induced by activation of the heating element. After multiple cycles, the cell went into thermal runaway during a charging procedure. Please note, that in the end, the test was disrupted multiple times due to problems induced by the high temperatures. Temperature readings of 9999°C (Upper range) due to sensor failure have been replaced by NaN. Since the heating is started delayed into the second WLTC cycle, the first cycle can be used as reference for normal operation.

Columns
t_s
Test time in seconds

I_meas_A
Applied current

U_meas_V
Voltage response of cell

T_?_C
Temperature reading of sensor ?. See above for description of the individual sensor positions. 

4. LocalThermalFault

Description

During cycling the cell with a continuous WLTC cycle, the thermal fault was induced by activation of the heating element. After multiple cycles, a charging process and observation, no thermal runaway occurred. Please note, that in the end, the test was disrupted multiple times due to problems induced by the high temperatures. It seems that the heat transfer into the cell could have been optimized, as shown by the relatively low cell temperature despite the hot heating element. Nevertheless, this experiment can be used to investigate online detection of small cell changes due to local heating - even without thermal runaway. Since the heating is started delayed into the second WLTC cycle, the first cycle can be used as reference for normal operation.

Columns
t_s
Test time in seconds

I_meas_A
Applied current

U_meas_V
Voltage response of cell

T_?_C
Temperature reading of sensor ?. See above for description of the individual sensor positions.