Coupled Electrochemical-Thermal Simulations and Validation of Minichannel Cold-Plate Water-Cooled Prismatic 20 Ah LiFePO4 Battery
Round 1
Reviewer 1 Report
This study numerically modelled the minichannel cold-plate water-cooled prismatic 20Ah LiFePO4 battery by electrochemical-thermal coupling.
The author also compared numerical results with experimental results.
Numerical results qualitatively agreed with experimental results, which shows the effectiveness of this model.
However, I have several concerns that need to be addressed before considering publication.
- Comments:
The author closely surveys previous results, but it seems that the facts are listed. The author should address the relationship among previous works and summarize it. - Is the change of density due to the temperature change considered in your simulation?
- In figure 6, numerical and experimental results are very different. Where does this difference come from?
- Can your numerical model apply to another battery?
- I cannot understand the novelty and the difference compared with the previous study. What is the originality and advantage of your numerical model?
Author Response
Dear Reviewer,
Please find the responses in the attachment.
Thank you with regards,
Jeevan
Author Response File: Author Response.pdf
Reviewer 2 Report
Greetings,
The paper presents the comparison between measurements and simulations of cold-plate cooled battery. Simulations were performed using coupled electrochemical-thermal model using Comsol Multiphysics.
Overall, it’s a very good article which I read with great interest. I only have several minor suggestions, which, in my opinion, would increase the quality of the paper even more.
- Authors used four boundary layers in the wall-fluid region. From my experience, more layers are usually necessary to properly model boundary effects. Did Authors try using a mesh with more boundary layers (6-10)? Does the study presented in the section 3.4 involved adding more layers in this region or just general mesh refinement in the entire channel?
- Some tables could be organized in a better way. For example, the Table 3 lists the same 3 properties for 4 model parts, so it could be organized as a table with 4 rows and 3 columns. Similarly, the table 2 lists a lot of parameters for positive/negative electrode: it would be advisable to use two columns, each for each electrode.
- On page 15, lines 453-456 Authors give the relative error of simulations results with respect to the measurements. However, it seems that the relative error values are calculated using the absolute value of the temperature. In my opinion, the relative error values should be calculated using not the temperature, but the temperature rise above the inlet temperature. I realize that it would mean that the errors will be much higher, but this method is definitely more correct. If Authors don’t want to use such high relative error values, then I suggest using absolute error values in degrees Celsius instead.
- In general, my biggest reservation is about the conclusions. The ones offered by the Authors are of course correct, but there could be a little more depth in the Authors’ analysis. The differences between simulations and measurements are of course perfectly understandable with such a complex model, however, discussing more deeply the possible reasons behind them and the sources of error would, in my opinion, greatly improve the significance of the paper. For example, in Figure 11, we can clearly see three phases in the measurements: a rapid rise at the start, then the plateau region, then again a rapid rise at the end. While for the simulations the curves seem to exponential (1-exp(-x)) shape. Why is there such a big difference in the shape of the curves?
Author Response
Dear Reviewer,
Please find the responses in the attachment.
Thank you with regards,
Jeevan
Author Response File: Author Response.pdf
Reviewer 3 Report
In this manuscript, a two-way coupled electrochemical-thermal simulation are performed at different discharge rates (1-4 C) and coolant inlet temperatures (15-35℃). All the tests and simulations are based on a prismatic 20 Ah LiFePO4 battery sandwiched between two minichannel cold-plates. The predicted temperatures are in good agreement with the measured data, confirming this Li-ion model can be used to design the efficient BTMS at cell level. However, some issues need to be resolved and adjusted. Therefore, we would recommend it to be minor revised before published by
Electrochem.
- This introduction is just a simple list of the published work. These works are too burdensome and lack comprehensive summary to point out the challenges of the existing battery management system. It is suggested to simplify some literature survey and modify it as a more reasonable introduction.
- The coolant inlet temperatures mentioned in this paper are set as common temperatures: 15-35℃. However, with the increase of complexity in practical environmental, temperatures below 15 ℃ and >35℃ are also frequent, so can this BMS is suitable to such temperatures?
- If possible, please provide the predicted and measured temperatures based on different cycles.
- Infrared thermal imaging should be provided to correspond to the predicted battery surface temperatures with minichannel cold-plate in Figure 8.
- If the batteries encounter hash conditions such as thermal abuse, can this cold-plate transport some thermal to decrease the temperature to increase the battery safety?
- The materials, cost, mass and volume of this cold-plate with minichannels should be provided.
Author Response
Dear Reviewer,
Please find the responses in the attachment.
Thank you with regards,
Jeevan
Author Response File: Author Response.pdf
Reviewer 4 Report
In this paper, Akkaldevi Chaithanya et al. simulated the electrochemical thermocouple model in LiFePO4 battery by using COMSOL software. The research method of the article is single, but the data is detailed. It is recommended that it be published after careful revision. 1. The recent advances in batteries (e.g. Enabling Argyrodite Sulfides as Superb Solid-State Electrolyte with Remarkable Interfacial Stability against Electrodes reviewed in Energy Environment Materials 2021, doi: 10.1002/EEM2.12282) and related research work using LiFePO4 or NCA as a cathode (1. ACS Appl. Energy Mater. 2019, 2, 6288-6294. 2. Journal of Materials Science & Technology 76 (2021) 156–165. 3. Scripta Materialia 185 (2020) 134–139. 4. Journal of Energy Chemistry 59 (2021) 229-241) should be introduced in the revised backgrounds. 2. In the electrochemical thermal simulation process of the battery, what is the difference between the thermal simulation in the traditional liquid battery and the all solid-state battery? 3. The formulas and main simulation methods in the text lack literature support. 4. The captions in Figures 11, 12 and 13 in the text are not clear, please indicate the meaning of the dashed and solid lines clearly. 5. The language expression and unit and subscripts in the text are not standardized, please check carefully.Author Response
Dear Reviewer,
Please find the responses in the attachment.
Thank you with regards,
Jeevan
Author Response File: Author Response.pdf
Reviewer 5 Report
The manuscript reported quantitative validation for prismatic 20Ah LiFePO4 battery. The Li-ion model provides perspective on designing the efficient BTMS at cell level. Herein, I recommend the publication of this manuscript in Electrochem after minor revision by addressing the following concerns:
- To emphasize the novelty quantitative validation of this work, please simplify the “Introduction and Literature” section.
- As shown in Figure 6, why were the voltage-time curves of 3C and 4C measured unsmooth? Please discuss about it.
- In this manuscript, please recheck the reference citation, which the Refs. 3-28 are lost in the text.
- The horizontal and vertical coordinate name should be presented in bold in Figure 10-13.
- There are lots of mistakes, such as the subscript of 4 in LiFePO4. Please recheck the manuscript carefully.
Author Response
Dear Reviewer,
Please find the responses in the attachment.
Thank you with regards,
Jeevan
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
The author's revisions have clarified the originality and purpose of the paper. Therefore, we strongly recommend its publication in this journal.
Reviewer 2 Report
I have no further comments
Reviewer 5 Report
According to the referee’s comments, the authors corrected the contents of the paper, and has answered referee's problem detailed in the revised manuscript. The quality of the revised manuscript is much better now. I think that this revised manuscript is suitable for publication.