Li-Ion Cell Safety Monitoring Using Mechanical Parameters, Part 3: Battery Behaviour during Abusive Overcharge

Round 1

Reviewer 1 Report

The article " Li-ion cell safety monitoring using mechanical parameters, Part 3: battery behavior during abusive overcharge" reports the results of a study about abusive overcharge in constant current and constant voltage mode.

Generally, the presented topic is very important and interesting. However, the presented form of the experimental assumptions and methods is not clear. The authors mention that “the same measurement series presented in part 1 and part 2 of this communication [15, 16]”, but the list of references show not full information about the previous documents. It is also visible that the previous parts are (or will be) published in another journal:

15. A. Kirchev, N. Guillet, D. Brun-Buission, V. Gau, J. Electrochem. Soc., 169, 010515 (2022)

16. A. Kirchev, N. Guillet, L. Lonardoni, S. Dumenil, V. Gau, “Li-ion cell safety monitoring using mechanical parameters, Part 2: battery behavior during thermal abuse tests”, submitted to J. Electrochem. Soc.

Consequently, I recommend presenting a minimum of information about the experimental layout in the actual article. Also, photos of the observed battery deformation would be very helpful for a reader in understanding the described phenomenon.

Finally, it is not clear how the observed and monitored over-swelling phenomenon is going to be used for battery safety improvement. In conclusion, the authors mention a further overcharging process and temperature increase, which activate the CID, so it is unclear what exactly is used as a monitored safety parameter.

minor corrections sugested

Author Response

Dear Reviewers,

I would like to thank you for the critical comments and notes, which helped to improve the quality of the manuscript. Please find below the reply to the recommended corrections:

 

Reviewer 1:

Generally, the presented topic is very important and interesting. However, the presented form of the experimental assumptions and methods is not clear. The authors mention that “the same measurement series presented in part 1 and part 2 of this communication [15, 16]”, but the list of references show not full information about the previous documents. It is also visible that the previous parts are (or will be) published in another journal:

15. A. Kirchev, N. Guillet, D. Brun-Buission, V. Gau, J. Electrochem. Soc., 169, 010515 (2022)
16. A. Kirchev, N. Guillet, L. Lonardoni, S. Dumenil, V. Gau, “Li-ion cell safety monitoring using mechanical parameters, Part 2: battery behavior during thermal abuse tests”, submitted to J. Electrochem. Soc.

Authors: The bibliography of the manuscript has been updated.

 

Consequently, I recommend presenting a minimum of information about the experimental layout in the actual article. Also, photos of the observed battery deformation would be very helpful for a reader in understanding the described phenomenon.

Authors: we added two more figures as supplementary information presenting images of the sensors set-up. There were no changes of the cells appearance after the abusive tests due to the early activation of the CID. The calculations based on the strain data in Figure 1 and 3 show that a radial deformation of 1000 ppm (gauge “J2”) increases the cell diameter from 18 mm to 18,02 mm. The measurement of such small changes in the cell size (apart from the strain gauge and acoustic interrogation techniques) is rather complex task requiring a dedicated equipment.

 

Finally, it is not clear how the observed and monitored over-swelling phenomenon is going to be used for battery safety improvement. In conclusion, the authors mention a further overcharging process and temperature increase, which activate the CID, so it is unclear what exactly is used as a monitored safety parameter.

Authors: The measurement of the strain using a single gauge or a rosette comprised of three gauges is based on a Weston bridge type of circuits transforming the voltage signal into a deformation. The strain signal reset a the point corresponding to State of Charge equal to 100% allows rapid and early detection of the overcharge process as over-swelling, because the discharge process itself causes a shrinkage of the cell diameter. The principle is demonstrated and commented in Figure 1f, 1g, 3e, 3f and  3g, as well as in Figure 2 and 4.

Reviewer 2 Report

Before this manuscript can be considered for publication, the following issues must be addressed by the authors:

1. "10 kOhm" in the text should be changed to either 10,000 Ohm or 10 kΩ. "kOhm" is very rarely used in scientific papers.

2. Introduction does not cover enough literature review of others' work. Also, authors only reviewed battery overcharge literatures regarding electrochemistry aspect in the Introduction. Authors should add literature reviews on battery overcharge regarding "mechanical parameters" aspect, which is the focus of this research.

3. Pictures of the experimental setup must be added. In addition, diagrams showing the exact locations (with dimensions) and orientations of the strain gauges must be added.

4. Detailed specifications of the battery cells used in this research should be summarized in a table and added in the manuscript, including dimensions, weight, cathode and anode materials, nominal voltage, nominal capacity, specific power, impedance, internal resistance, etc.

5. Figure 5b needs to be revised. It does not have x-axis or y-axis.

6. This research is only about experiments on certain type of battery cell. There is not any modeling and simulation involved. Without a general simulation model developed, the proposed results are only valid for this certain type of battery cell. The results cannot be applied to other battery cells, which significantly reduces the value of this research. Authors should add simulation models, such as FEA models in ANSYS and battery models in Simulink or ANSYS Fluent.

Author Response

Dear Reviewers,

I would like to thank you for the critical comments and notes, which helped to improve the quality of the manuscript. Please find below the reply to the recommended corrections:

 

Reviewer 2:

 

1. "10 kOhm" in the text should be changed to either 10,000 Ohm or 10 kΩ. "kOhm" is very rarely used in scientific papers.

Authors: the manuscript has been corrected considering this remark.

 

2. Introduction does not cover enough literature review of others' work. Also, authors only reviewed battery overcharge literatures regarding electrochemistry aspect in the Introduction. Authors should add literature reviews on battery overcharge regarding "mechanical parameters" aspect, which is the focus of this research.

Authors: The bibliography of the manuscript has been updated.

 

3. Pictures of the experimental setup must be added. In addition, diagrams showing the exact locations (with dimensions) and orientations of the strain gauges must be added.

Authors: two new figures containing the required information have been provided as supplementary information.

 

4. Detailed specifications of the battery cells used in this research should be summarized in a table and added in the manuscript, including dimensions, weight, cathode and anode materials, nominal voltage, nominal capacity, specific power, impedance, internal resistance, etc.

Authors: The requested information can be found in the beginning of Paragraph 2 of the manuscript. It has been denoted that more details can found in the reference [17 / A. Kirchev et al, J Electrochem Soc, 169, 010515 (2022)], including results from a thorough characterization of the cell electrodes, electrolyte and separator.

 

5. Figure 5b needs to be revised. It does not have x-axis or y-axis.

Authors: the figure caption has been revised mentioning that the plot is a pseudo 3D representation of the acoustic data clustering process.

 

6. This research is only about experiments on certain type of battery cell. There is not any modeling and simulation involved. Without a general simulation model developed, the proposed results are only valid for this certain type of battery cell. The results cannot be applied to other battery cells, which significantly reduces the value of this research. Authors should add simulation models, such as FEA models in ANSYS and battery models in Simulink or ANSYS Fluent.

Authors: we are working on the development of COMSOL Multiphisics model allowing the simulation of the mechanical changes due to the electrochemical processes. The results will be an object a future publication.

Round 2

Reviewer 1 Report

TMy sugested corrections have been implemented. Thank you.

Reviewer 2 Report

Thank you for improving the manuscript.