Study on the Formation and Evolution Mechanism of Pinhole in Aluminum Foil for the Lithium-Ion Battery Soft Packaging

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

Soft packaging is technologically important for improving the energy density of the cell and minimizing the complexity of battery packaging, potentially reducing the battery cost. Therefore, lithium-ion battery soft packing materials such as aluminum-plastic laminated film are crucial for battery industries. However, they are usually vulnerable to defects and punctures due to their thin morphology, potentially causing safety issues. This manuscript by Zhang et al. reports on a detailed study of one of the issues related to the manufacturing process of aluminum foil, focusing on the cause, formation, and evolution of pinholes on aluminum foil that serve as a barrier and shaping element for lithium-ion battery soft packing. Although the work has significance regarding technological engineering advancement, the manuscript needs a significant and thorough revision to improve its quality. I recommend addressing the following points carefully to improve the overall quality of the manuscript.

1. First and foremost, grammatical issues should be addressed rigorously and thoroughly. There are significant issues relating to grammatical errors throughout the manuscript.
2. In line 99, the "rolling reduction ratio" should be defined first.
3. In line 101, what shape of Fe2O3 authors trying to infer to?
4. Fig 2 is not mentioned anywhere in the body text, and should be described adequately. Authors should note that the body text should include each and every panels of the figure described/mentioned where it is appropriate. For example, if Fig. 2 has two panels, then both of them should be explicitly mentioned in the body text, otherwise there is no point of using figures. This should be followed throughout the entire manuscript. Also, there is a lack of consistency using figure caption heading, either "Fig." or "Figure" should be used.
5. "A" and "B" should be separated from "particle" in Fig 1 label.
6. 4, 5, & 6 captions should be revised to make it easy to understand.
7. Either experimental data or reference(s) should be provided for the sentence in lines 174 and 175 as "Typically, the filtering aid...".
8. In line 201-203, authors conclude that particles containing iron and chrome were not the cause of creating pinholes despite being their sizes comparable to the foil thickness due their flaky character and presence of ductile metal elements. Then, it should be clarified that if these particles are chemically attached with the matrix or simply anchored in the matrix. If they are simply anchored, should not this make the matrix area vulnerable to creating pinholes eventually with nominal stress?
9. In Lines 208 & 211, which "mark A" and "mark B" authors refer to? Are these marks shown in any Figures? It should be clarified. Were these pinholes artificially created just for the experimental purposes or created in the real world scenario (industrial matrix formation environment)? If they were created only for the study purpose, do their dimension correctly represent realistic scenario?
10. In Fig. 7, the rolling direction should be provided in the images.
11. In the sentence "As is demonstrated in Fig. 7, the pinhole exhibited an increase followed by a decrease during the rolling process." (Line 248-249) what actually increased and decreased? please clarify it.
12. In line 269, does "Fig. 11" correctly represent what the sentence is explaining? Shouldn't it be Fig. 9? Please, carefully revise it.
13. The line 276 defines "Si" twice. Please, make correction to it.
14. What are the units of average of coefficients Ai and Bi, in lines 281 and 282?
15. Error between actual and predicted pinhole area using proposed model is ~39%, which is significantly high. Therefore, it questions the effectiveness of the proposed model. Authors should include more parameters to make the model realistic.
16. Why surroundings of Fig. 11a & b look entirely different than that of Fig.11c & d? Does it mean, all four different conditions were not tested in the same pinhole? It should be clarified.
17. In line 352, h0 and h1 are said to be in %. Is it correct? Please, make sure of it.
18. Lines 354-355 indicate that Table 8 presents the extension ratios of aluminum foil and foreign particles calculated according to formulas (6) and (7). But which row/column is calculated using formula (7)? Please, revise it.
19. 12 should be labeled as "a" and "b", clearly indicating their difference in the caption.
20. Line 427 mentions Figure 16, but manuscript does not have Figure 16. Please, revise it.

Comments on the Quality of English Language

Grammatical issues should be addressed rigorously and thoroughly. There are significant issues relating to grammatical errors throughout the manuscript.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

 

The manuscript entitled “Study on the formation and evolution mechanism of pinhole in aluminum foil for the lithium-ion battery soft packaging” is devoted to the study of defects in aluminum foil due to microparticles in the foil rolling process. The manuscript by its content satisfies the subject and requirements of the journal Coating. The topic is quite relevant because aluminum foil is used in LiB fabrication. I believe that the manuscript can be considered for publication after additions and improvements.

- The cause of defects due to microparticles is mainly due to contamination of the workspace and equipment. Add the reasoning of how the cost of foil would increase significantly if the requirement for cleanliness of the space and the production itself were significantly increased.

- Since this paper treats the aluminum foil as part of the lithium battery, it is not clear how defects (not through holes) will affect the performance and longevity of the battery. Add a section devoted to this issue.

- Since the process of defect formation during rolling is a kinetic process, add the rolling rates that were used.

- small font on graphs, enlarge it considerably

- In the tables in some cases the sum of wt.% is not equal to 100%. It is necessary to indicate why.

 

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

The manuscript has been revised satisfactorily and deserves to be published in the journal Coatings.

Reviewer 2 Report

Comments and Suggestions for Authors

The corrected version of the manuscript looks much better. The authors have commented extensively on my comments. They have made appropriate additions to the text of the manuscript. I have no comments and believe that the manuscript can be considered for publication without further corrections.