A Strategy for Measuring Voltage, Current and Temperature of a Battery Using Linear Optocouplers

Round 1

Reviewer 1 Report

The article focuses on o input voltage, current, and temperature measurement circuit development for automotive applications. Even though the undertaken topic is interesting, the submitted paper should be improved before publishing.

Major remarks

The authors developed a measurement system. Consequently, it should be tested using accurate voltmeters, ammeters and thermometers, which should also have calibration certificates. But, in the paper, the authors even mentioned how the comparative measurement was performed.

The authors should point out the advantages of their solution. The presented system is very simple and does not seem to outperform the existing solutions. The only asset mentioned by the authors is related to using 12-bit ADC, which can increase measurement resolution. But, the resolution of the converter is not the only factor that influences the accuracy. The sensor's circuit should be capable of discerning these small changes correctly. Based on the authors' assumption, usage 16-bit ADC should be better than 12-bit converter. So the question is why the authors did not use it.

The authors claim that the presented solution can be used in automotive applications. But, they developed only a model of BMS. Therefore, they should point out how this model reflects the capability of the real system and if it obeys the rules of restrictive automotive norms.

In Conclusion, the authors claim that the presented solution is more accurate than the existing topologies. But any comparison to other methods, which is highly demanded, was presented.

The experiment section focuses rather on the battery stack performance than on the measurement system. As mentioned previously, the system's accuracy under different conditions should be researched, and its reliability should be proven.

Major remarks

The paper lacks technical soundness (e.g. the authors use the term sense voltage instead of measure voltage). Moreover, there are plenty of editorial errors (e.g. line 22, line 169 – Adc, line 182 (iii), line 194 – used variable declarations from code).

 

Lines 84-90, which describe the performance of the presented system, should be included in the Conclusion.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 2 Report

I have read the submitted article entitled “A strategy for measuring Voltage, Current and Temperature of a Battery using Linear Optocouplers” by S. E. Mathe et al to Wevj/MDPI. Energy storage technology is one of the most critical technologies for the development of new energy electric vehicles and smart grids. Among the energy storage technologies, lithium-ion technology is an attractive energy storage device exhibiting excellent efficiency of charge-discharge processes along with high energy density. They are an indispensable power source for a variety of portable electronic devices and EVs today. It is critically important that lithium-ion battery stacks have a good battery-management system for monitoring many cell voltages and cell temperatures. Without that monitoring, thermal runaway can lead to a battery explosion. In the current work, the authors have proposed a battery management system design, based on linear optocouplers for Lithium-ion battery cells for automotive/stationary applications. The demonstrated methodology for measurements appears to be novel and useful to the community. The manuscript is written OK but the main concern of this paper and the areas that require clarification are given below.

·         The aim of the current work in proposing a methodology and its importance needs to be emphasized in the introduction part.

·         The safe cut-off voltage for a lithium-ion battery to charge and discharge the system needs to be provided.

·         Please provide the parameters reflecting the sensitivity of the types of optocouplers as an average for their respective range.

·         Are there any restrictions for the number of modules to be connected in series in a pack for safe and efficient measurements?

·         Li-ion battery configurations and their relevant intercalation mechanism for electric vehicles, and their recent designs need to be mentioned and referred to in the material reported in the literature (such as Progress in Solid State Chemistry 62 (2021) 100298; doi.org/10.3390/en13061477, and doi.org/10.1016/j.jpowsour.2005.03.184). Figure 1 and its text can be referred to in these works.

·         Figures 12- 15, why do the charge and discharge curve plots show different C-rates; 0.5 C and 1C?

·         The shape of the charge and discharge curve need to be briefly explained.

·         Are the experiment values validated against the theory?

·         Throughout the manuscript, there are quite a few syntax errors that need to be fixed. The acronyms can be explained.

 

·         Section 2, different amplifiers, and driving transistors can also be mentioned.

Author Response

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Author Response File: Author Response.pdf

Reviewer 3 Report

1. line 37：  in order to measure SOC voltage， what does SOC voltage mean？

2.  The second part elaborates on SOC, but the research in this paper is to detect the voltage of the cell, the current and temperature of the battery pack, and what is the relationship between the SOC and the cell voltage?

3.  VOMA618A and IL300 optocoupler is descrived in the second part introduces. Why is PIC817 used in the experiment?

4. The temperature is different between cells. In this paper, the temperature of the battery pack is measured. Can this method ensure the safety of the battery pack?

5. Line 111: in the article, the capitalization of the first letter of micro controller is inconsistent.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

The manuscript can be published in WEVJ.

Reviewer 2 Report

The revised version is suitable to publish,