Soc Estimation of the Lithium-Ion Battery Pack using a Sigma Point Kalman Filter Based on a Cell’s Second Order Dynamic Model

Round 1

Reviewer 1 Report

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Author Response

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Reviewer 2 Report

Review of “Soc Estimation of The Lithium-Ion Battery Pack using Sigma Point Kalman Filter Based on Cell’s Second Order Model”

 

The writing of this paper must be deeply improved.

Some parts of the text have been let in vietnamese (as far as I could guess !). Some english words are written differently in different part of the text : modul or module ; some are miss-written “eppecially”.

Acronyms must be explicitly defined in the main text and not only in the abstract.

Sign conventions for voltage and current (fig 2 for instance) must be checked

equations must be checked : for instance in equation 2 and 3, it seems that “R1” is used instead of “R2” in some indexes.

In equation 4 and figure 3 the notation is confusing between cell voltage and noise voltage (it is hard to distinguish the two symbols)

in figure 4 the legend of the different curves is missing

In table 2-3-4 the number of decimals seems not adapted

 

Concerning the scientific contents, the originality of the work is not sufficiently highlighted. The authors claimed to have used a SPKF algorithm and a second order model in order to estimate SOC of a pack. Does the new contribution concern the methods or the fact that they are applied to a pack ?

 

On this particular point, I do not understand the effect of the pack configuration. The Np cells in parallel after a period of stabilization have the same voltage (and the same SOC) and could be considered as a single cell (as the authors mentioned in the paper). For the Ns “cells” connected in series, the algorithm computes the SOC of each of them. The fact that they are in series has no impact in the process (as far as I understand). The same computation would be done if the Ns cells were non connected. So what is the point to consider them connected?

From my understandin, the present paper does not give information on the SOC of the pack as the latter is not the sum of the SOC of each cells connected in series. The total SOC depends on the capacity and the SOC of each cell and also the state of balance between the cells.

 

The authors have to clearly highlight the novelty in their work and justify the interest for estimation of SOC of a pack.

Author Response

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Reviewer 3 Report

The topic of this work is very interesting. The authors provide a pretty detailed design of SoC estimation. However, some significant modifications are needed before the manuscript is accepted. Below are some detailed issues with this manuscript:

In order to make the audience has a more clear understanding of this method, some background information regarding Sigma Point Kalman Filter (SPKF) should be added in the Introduction section. Legends representing the currents and SoCs of 4 cells are needed for Figures 4 and 5. The details of general algorithms and algorithms of SPKF 1 and SPKF 2 should be moved to the appendix section. In Figure 7, the name of the vertical axis is not correct. Also, what do Figure 6 and 7 indicate? The authors need to give some discussion of the results. Tables 2, 3 and 4 should be moved to the appendix section. What do Figure 8 and 9 indicate? The authors need to give some discussion of the results. The authors claim that “From the SoC estimation results, we see that after about 0.01h, the SoC estimations of the cell modules are close to the actual average SoC of the cell modules.” Are the authors sure it is after about 0.01hr? The authors claim that “these errors are quite small when compared with the methods mentioned in the documents”. I didn’t see the comparison, otherwise, this statement is not reliable. I don’t understand the title of Figure 14. Please write in English. Also, the names of vertical axes are missing.   In Figure 15, all the plots share a similar shape except Module 4. Could the authors explain why the plots in Module 4 look like that?   There are many typos in the manuscript. Please correct the spelling.

 

Author Response

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Round 2

Reviewer 1 Report

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Comments for author File: Comments.pdf

Author Response

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Reviewer 2 Report

Review of the revised paper “Soc Estimation of The Lithium-Ion Battery Pack using Sigma Point Kalman Filter Based on Cell’s Second Order Dynamic Model”

 

The writing of the paper has been greatly improved but too many mistakes are still present. More corrections are needed.

Examples of english mistakes : “epecially” for “especially” (page 2) - “illustration the process” for “illustration of the” (page 5) - “Initial” for “initialize” (page 6)

Authors have to check again the english writing and indicate each correction in the new revised text.

Examples of mistakes : “parallel” instead of “series” (page 6) – n° of figure cited in the text is not the right n° (at least twice) – page 11 authors talked about “9 cell modules” instead of 7

The names of the parameters of the model listed page 5 are different from the parameters given in table 1

The capacity of the cell is given as 2500 mAh in the text page 7, but the value of capacity of cell is 22 Ah in table 1 and table 4

In page 8 authors claim that the “capacity is 600W” - what is this value ? Why a capacity in W ? this statement needs to be corrected

In page 10 the authors claim that the soc estimation is close to the real value after 0.01h but in figure 11, one would say 0.1h ; to be clarified

Authors have clarified most of the points noted in the first review – I thank them for their effort. However one of these points is still not clarified concerning the number of decimals in table 2 – 4. By giving a value of 22.41404 Ah for the capacity, authors meant that the accuracy is 5 10^-5 %. This seems not possible to me; this is why I claim that less decimals would be more relevant.

Author Response

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Reviewer 3 Report

The authors have modified the manuscript based on my suggestions, and the updated version of the manuscript is acceptable. 

Author Response

Authors thank you very much for spending your time to review our revised manuscript.   

Round 3

Reviewer 1 Report

Publish as is.