Research on the Influence of Liquid on Heat Dissipation and Heating Characteristics of Lithium-Ion Battery Thermal Management System

Round 1

Reviewer 1 Report

The paper « Research on the Influence of Liquid on Heat Dissipation and Heating Characteristics of Lithium-ion Battery Thermal Management System» by Chuanwei Zhang, Jing Huang*, Weixin Sun, Xusheng Xu and Yikun Li is dedicated to numerical simulations if a Lithium-ion Battery Thermal Management System having liquid as a media both for cooling and heating p

urposes.

The paper theme is of interest but performed research produce several major questions and includes rude mistakes.

• Performed study is explained insufficiently leaving unclear the exact parameters of the work performed and making it difficult not only to understand it, but also the possibility of using the results obtained.
  • What is the liquid under consideration? What properties does it have? λ in eq.3.3 is given for thermal conductivity of water and k_l in eq.3.4 is given for thermal conductivity of “liquid”. Are they the same?
  • No comments are given to specify the turbulence. The flow is laminar?
  • As far as I understand variable inlet/outlet pipe diameter is a size of two collector pipes outside of the LBTMS box. All other geometry is fixed. If it is so than it should be specified directly.
  • It is not clear where authors solved steady state problem and where it is time-dependant solution? Experimental verification is time dependant. What about different BTMS design simulation?
  • It is not clear how authors calculate the heat transfer coefficient h
• Results are controversial and require explanation.

 

• Performed Grid independence verification is confusing. Temperature is used to estimate quality of grid while no governing parameter is given. What are flow rate and heating rate for this case? Time-dependant or steady state solution is used for this analysis? Changes of temperature for 0.025 degrees Kelvin seems to be unnoticeable from engineering point of view any practical cause and possible connection with experiment.
• Size of this pipes should not significantly change the performance of the system if hydraulic diameter of pipes is similar to the sum of used subchannels. There might be some critically low pipes size which will choke the flow. However, performed analysis is not capable to give this recommendation from the results. It is given only in conclusions.
• It is better to specify thermal parameters of different observed states with for example values of total heat released in the system. Charge and discharge parameters otherwise require to some recalculations which are possible but complicate perception .
• For heating liquid author use low temperature environment of 253K (line 219). It is -20 Celsius . Would not water freeze at this temperature?

 

 

• Conclusions are too obvious and do not represent the work being done.
  • First conclusions says:

“10mm pipe diameter is the optimal size for this BTMS.”

This should be clearly shown in result section. Discussion of fig. is not sufficient.

• Second conclusion says:

“The greater the flow rate, the greater the BTMS pressure difference…”

“The increase of flow rate can 337 increase h and Nu.”

“As the flow rate increases, the growth rates of h and Nu gradually decrease. Therefore, choosing the right flow rate is very important for liquid-based BTMS.”

The statements repeat each other, are accessible from a common understanding of thermal hydraulics and do not carry any new information.

• Third conclusion:

“In order to balance the cell surface temperature, the fluid temperature should not be too high when BTMS heats the cell.”

Too general statement that requires any quantitative estimates.

 

• Figures are poorly prepared and are given straight from the Fluent. They are difficult for perception.
• First major disadvantage of the paper is bad language with multiple examples of passive voice and articles Spacebars are missing. Proofreading is required.

 

Minor questions:

6) Reynolds number is defined INCORRECTLY. Stated in eq (3.5) form will produce dimension value.

7) Significant digits are excessive in many cases for example Pressure on lines 263, 290.

8) If it is possible, please, specify the exact type of commercial battery being under consideration.

9) heat transfer coefficient h should be defined upon first mention.

 

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 2 Report

The paper could be accepted after addressing the following issues: 1-The English of the paper must be improved. 2- There are a lot of common explanations through the text. It is better to remove these sections: e.g., Relations 2.1 to 2.3. 3-Design a more attractive illustration for Fig. 1. 4-Add a schematic part to figure 3a. 5-Line 232: Something is missed here. 6-Add limitations of your study and the possible future works in this area. 7- It is better to combine several figures in one figure in results and discussion part. 8- Enhance the resolution of figures and use one format for all of them.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

The authors have significantly improved the paper.

However, there are still major questions:

• If the flow is turbulent as authors have clarified in revision than it should be mentioned what turbulence models are used in the study.
• Grid independence study is still confusing as it does still does not contain information on velocity and pressure convergence. The problem under consideration includes hydrodynamical part which grid-independence isa not discussed.
• h is defined according to equation (3.3) allowing to calculate the value from balance ratios without any simulation at all. Equation (3.3) also includes velocity as a vector; therefore, h is a vector?

 

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 2 Report

The paper can be accepted after editing the text. 
In addition, it is better to combine some figures in one multi panel figure.

Author Response

Please see the attachment.

Author Response File: Author Response.docx

Round 3

Reviewer 1 Report

The authors answered my questions.

I strongly recommend to include clarifications from these answers in the text of the paper to improve the perception of the material. The article can be accepted for publication