Cited by 160Advanced Battery Technologies ResearchAdvancements in Battery MaterialsPower Systems and Renewable Energy

A Practical Lithium-Ion Battery Model for State of Energy and Voltage Responses Prediction Incorporating Temperature and Ageing Effects

Open access
Li, Kaiyuan, Wei, Feng, Tseng, King Jet, Soong, Boon-Hee·2018·IEEE Transactions on Industrial Electronics

Abstract

The state of energy (SOE) is a key indicator for the energy optimization and management of lithium-ion (Li-ion) battery-based energy storage systems in smart grid applications. To improve the SOE estimation accuracy, a Li-ion battery model is presented in this study against dynamic loads and battery ageing effects. First, an electrical battery model is combined with an analytical model in order to take advantages of both models for accurate prediction of battery terminal voltage characteristics, SOE, and remnant runtime. Second, a novel method to separate the fast and slow dynamics of the electrical battery model is developed, and its superior performance is presented. Third, the effects of the battery initial SOC, load current rate and direction, operating temperature, and ageing level are systematically scrutinized and involved in the proposed model for robust SOE and terminal voltage prediction. Commercial Li-ion batteries are then tested under dynamic loads and at an arbitrary battery ageing level to validate the effectiveness and robustness of the proposed model. The laboratory-scale experimental test results show superb accuracy and reliability of the proposed battery model for estimating battery SOE and terminal voltage under dynamic loads and battery ageing conditions.

AI snapshot

Written from the paper’s full text.

TL;DR

The paper proposes a hybrid Li-ion battery model combining a 2nd-order RC electrical model with an analytical SOE/runtime model, incorporating temperature, load, initial SOC, and ageing effects. Validation on commercial LTO cells shows low voltage and SOE errors under dynamic loads and arbitrary ageing, though some high-current SOE error remains.

Key findings

  • Voltage prediction: for an aged cell at 18.7 Ah (93.5% SOH), maximum discrepancy occurred at 0–10% SOC with MAPE 0.17% and RMSPE 0.23%; over 95–10% SOC, MPE was about 0.09% and RMSPE within 0.15%. Under a dynamic smart-grid current profile from 50% initial SOC for 30 h, MAPE was less than 2% and RMSPE 1.2%.
  • SOE prediction: at 0.33 C constant current with dynamic temperature, MAPE was 2%, RMSPE 1.1%, and runtime error within 1%. Under pulse load with initial SOE 80%, MAPE was 3.2% and RMSPE 2.1%. Under a 5 h dynamic smart-grid profile with initial SOE 58%, the proposed model had MAPE 9.2% and RMSPE 4.7%, versus 26% and 10.9% for the prior model in [35].
  • MAE and RAE varied with operating conditions: at 5 °C, MAE dropped from 41.26 Wh to 38.12 Wh when current changed from 0.33 C to 3.0 C; at 0.33 C and 25 °C, MAE was 46.59 Wh for a fresh cell and 44.78 Wh, 42.1 Wh, and 37.9 Wh for aged cells. The RAE ratio at 40% versus 100% initial SOC decreased from 38.8% at 0.33 C to 33.4% at 5.0 C.
  • Internal resistance \(R_i\) was nearly constant at about 10 mΩ within 10–90% SOC, with abrupt increases near 0% and 100% SOC; it depended on SOC, temperature, and SOH, but was almost independent of current rate, direction, and switch on/off phases.

Methods

  • The model combines a 2nd-order RC Thevenin ECM—OCV, ohmic resistance \(R_i\), fast \(R_fC_f\), slow \(R_sC_s\), and a relaxation offset \(U_{\text{offset}}\)—with an analytical SOE/runtime model using \(SOE = E_{RAE|I,T,SOC,SOH} / E_{MAE|I,T,SOH} \times 100\%\), coupled by online SOC.
  • Commercial LTO cells were tested: nominal 20.0 Ah, 2.3 V; temperatures 5, 15, 25, 35, and 45 °C; SOHs 100%, 95%, 90%, and 85% corresponding to 20.0, 19.1, 18.1, and 17.0 Ah. MAE/RAE look-up tables used currents from 0.33 C to 5.0 C and initial SOCs from 5% to 95%; pulse tests used 3.0 C PC/PD pulses, with validation on a fresh cell and aged cells including an arbitrary 18.7 Ah cell (93.5% SOH).
  • Parameter extraction used pulse/relaxation data, derivative-based separation of fast, slow, and offset voltage components, and offline multidimensional look-up tables; validation compared simulated versus measured voltage and estimated SOE against brute-force actual SOE obtained via the power-integral method.

Limitations

  • The paper states that irreversible and reversible energy loss were not discussed; only RAE and MAE under a designated load condition were considered, with future work needed on energy loss and recovery rate including idle time. It also assumes SOH and initial SOC are already known, ignores calendar ageing because it had negligible effects in their tests, and ignores hysteresis and self-discharge due to ≤2 mV hysteresis and regular cycling.
  • The paper states there is no direct online SOE determination method; actual SOE was obtained by a time-consuming brute-force procedure, which limits practical online validation.
  • Evident from the text: validation used only commercial LTO cells, so generality to other Li-ion chemistries is not demonstrated; the dynamic smart-grid profile showed a relatively high SOE MAPE of 9.2% under currents up to 3.0 C, even though RMSPE was 4.7%.

Model-written summary. Check it against the paper before relying on it.

Integrity signals

Registry

Crossref · 10.1109/tie.2017.2779411

Cites

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Claims the paper makes

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  • Findingown data
    § Abstract

    The proposed hybrid Li-ion battery model can predict online battery SOE and terminal voltage accurately under various operating loads and battery ageing conditions.

    “The laboratory-scale experimental test results show superb accuracy and reliability of the proposed battery model for estimating battery SOE and terminal voltage under dynamic loads and battery ageing conditions.”
    • Also stated in: § I. INTRODUCTION · plain
      “a comprehensive hybrid Li-ion battery model is advocated in this paper, which is capable of pred icting the online battery SOE as well as the voltage characteristics accurately under various operating loads and battery ageing conditions.”
    Quote in the paperSubstantial claim
    • The authors state this as an assumption: The SOH and initial SOC of the battery were already known.
  • Findingcitation
    § C. State of Health

    The extent of cell degradation in capacity was not correlated with the ageing or cycling conditions.

    “Moreover, according to our experimental results and that in [38], the extent of the cell degradation in capacity was not correlated with the ageing or cycling conditions.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [38] source

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  • Findingown data
    § B. Analytical Model Extraction Results

    At 5 oC, MAE dropped from 41.26 Wh to 38.12 Wh when current changed from 0.33 C to 3.0 C.

    “For instance, at 5 ºC, MA E dropped fro m 41.26 Wh to 38.12 Wh when I changed fro m 0.33 C to 3.0 C.”
    Quote in the paperNot a substantial claim
  • Findingown data
    § B. Analytical Model Extraction Results

    At the same temperature, MAE decreased with increasing current.

    “At same T, MA E decreased with increasing I.”
    Quote in the paperNot a substantial claim
  • Findingown data
    § A. OCV-SOC Characteristics

    Higher temperature resulted in a wider OCV range.

    “Fig. 9 revealed that higher T resulted in a wider OCV range.”
    Quote in the paperNot a substantial claim
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  • Classified as probably not a substantial claim. 13
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    Findingown data
    § B. Analytical Model Extraction Results

    When 0.33 C and 25 oC were chosen, MAE was 46.59 Wh for fresh cell, and 44.78 Wh, 42.1 Wh and 37.9 Wh for each aged cell, respectively.

    “Fig. 10(b) showed the MAE trajectory with SOH: when 0.33 C and 25 ºC were chosen, MAE was 46.59 Wh for fresh cell, and 44.78 Wh, 42.1 Wh and 37.9 Wh fo r each aged cell, respectively.”
    Quote in the paperNot a substantial claim
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    Findingcitation
    § C. State of Health

    Calendar-ageing caused negligible effects on battery performance, so only cycling-ageing effects were considered in this study.

    “Nevertheless, based on our test results published elsewhere and in [37], the calendar-ageing caused negligib le effects on the battery performance, thus only the cycling-ageing effects were considered in this study.”
    Quote in the paperSubstantial claim0 of 1 sources checked
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    Findingown data
    § B. Verification of Battery SOE and Runtime Estimation

    From 1.5-5 h when the cell was discharged at current rate as large as 3.0 C, the estimated SOE from the model in [35] deviated seriously from the actual one, while the SOE estimation of the proposed model was much closer to the actual one.

    “Fro m 1.5-5 h when the cell was discharged at current rate of as large as 3.0 C, the estimated SOE fro m the model in [35] deviated seriously fro m the actual one, while the SOE estimat ion of the proposed model was much closer to the actual one.”
    Quote in the paperSubstantial claim0 of 1 sources checked
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    Findingown data
    § VII. CONCLUSION

    Experimental results validated the efficacy of the proposed model with voltage prediction error less than 2%, SOE error no more than 4.7%, and runtime error within 1% under dynamic load conditions at an arbitrary ageing level.

    “The experimental results validated the efficacy of the proposed model with voltage prediction error less than 2%, SOE error no more than 4.7%, and runtime error within 1% under dynamic load conditions at an arbitrary ageing”
    Quote in the paperSubstantial claim
  • May combine two claims.

    Findingown data
    § A. Verification of the Terminal Voltage Prediction

    Under a highly dynamic current profile from 50% initial SOC for 30 hours, simulated voltage results superimposed very well with measurements, with MAPE less than 2% (found at the 8.5th hour when online SOC was approximately 12%) and RMSPE of 1.2%.

    “It could be observed from Fig. 22 that the simulated voltage results superimposed very well with the measurements, with the MAPE (found at the 8.5 th hour when the online SOC was approximately 12%) less than 2% and the RMSPE of 1.2%.”
    Quote in the paperSubstantial claim
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    Findingown data
    § C. Electrical Circuit Model Extraction Results

    R_f and R_s values dropped with increasing current rate, and R_f was slightly larger than R_s.

    “Meanwhile, R f and R s values dropped with increasing current rate, and the values of R f was slightly larger than that of R s .”
    Quote in the paperNot a substantial claim
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    Findingown data
    § C. Electrical Circuit Model Extraction Results

    For discharge regimes, battery voltage drop was more prominent at low SOCs when the cell was almost depleted due to build-up of concentration gradient, and R_f and R_s became very large due to slow mass transport and diffusion limitations.

    “For the discharge regimes, the battery voltage drop was more p ro minent at low SOCs when the cell was almost depleted due to the build-up of concentration gradient, and R f and R s became very large due to the slow mass transport and diffusion limitations.”
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    Findingown data
    § C. Electrical Circuit Model Extraction Results

    A downward trend with temperature of R_f and R_s values was observed, while C_f and C_s generally increased with rising temperature, more obvious for C_f than C_s.

    “A downward trend with temperature of R f and R s values could be observed, while C f and C s generally increased with the rising temperature, and it was more obvious for the values of C f than that of C s .”
    Quote in the paperNot a substantial claim
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    Findingown data
    § B. Verification of Battery SOE and Runtime Estimation

    SOE estimation at 0.33 C constant current load and temperature profile in Fig. 19 had MAPE 2% and RMSPE 1.1%, and runtime error within 1%, revealing the proposed model performed very well under constant load and dynamic temperature conditions.

    “The MAPE and RMSPE o f the estimation results were 2% and 1.1%, and the runtime error was within 1%, revealing that the proposed model performed very well under constant load and dynamic temperature conditions.”
    Quote in the paperSubstantial claim
  • May combine two claims.

    Findingown data
    § B. Verification of Battery SOE and Runtime Estimation

    The MAPE and RMSPE of the proposed model were 9.2% and 4.7%, while those of the model in [35] were 26% and 10.9%.

    “Specifically, the MAPE and RMSPE of the proposed model were 9.2% and 4.7%, wh ile those of the model in [35] were 26% and 10.9%, respectively.”
    Quote in the paperSubstantial claim0 of 1 sources checked
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    Findingown data
    § A. Verification of the Terminal Voltage Prediction

    U_i was present during both charge and discharge events and was almost constant because R_i varied minimally with SOC and current rate variations.

    “U i was present during both the charge and discharge events and it was almost constant because R i varied minimally with SOC and current rate variations.”
    Quote in the paperNot a substantial claim
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    Findingown data
    § B. Verification of Battery SOE and Runtime Estimation

    Under the pulse current load profile of Fig. 18 and temperature profile in Fig. 19, during the 1-hour test, good superimposition of estimated SOE with actual was observed, and MAPE and RMSPE were 3.2% and 2.1%.

    “During the 1-hour test, good superimposition of the estimated SOE with the actual one could be observed, and the MAPE and RM SPE were 3.2% and 2.1%, respectively.”
    Quote in the paperSubstantial claim
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    Findingown data
    § A. Verification of the Terminal Voltage Prediction

    A close agreement between simulated and measured voltage curves was observed, with maximum discrepancy at the end of discharge when the cell was nearly depleted (0-10% SOC), where MAPE was 0.17% and RMSPE was 0.23%.

    “A close agreement between the two curves could be observed, and the maximu m discrepancy was found at the end of discharge when the cell was nearly depleted (0-10% SOC), where the maximu m absolute percentage error (MAPE) was 0.17% and the root mean square percentage error (RMSPE) was 0.23%.”
    Quote in the paperSubstantial claim
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    Findingown data
    § A. Verification of the Terminal Voltage Prediction

    In the SOC range from 95% to 10%, MPE was approximately 0.09% and RMSPE was confined within 0.15%.

    “In the SOC range fro m 95% to 10%, MPE was appro ximately 0.09% and RMSPE was confined within 0.15%.”
    Quote in the paperSubstantial claim
  • May combine two claims.

    Findingown data
    § C. Electrical Circuit Model Extraction Results

    R_i values increased when the temperature was lower and battery ageing was more severe.

    “Basically, R i values increased when the temperature was lower and battery ageing was more severe.”
    Quote in the paperSubstantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingnone given
    § A. Verification of the Terminal Voltage Prediction

    U_s decayed more slowly in about 2600 s.

    “U s decayed more slowly in about 2600 s.”
    Quote in the paperNot a substantial claim
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    Findingown data
    § B. Verification of Battery SOE and Runtime Estimation

    From 0-1.5 h when load current was moderate (within ±1.0 C), both SOE estimations could achieve acceptable results, and the proposed model performed slightly better than the model in [35].

    “According to Fig. 26, fro m 0-1.5 h when the load current was moderate (within ±1.0 C), both the SOE estimation could achieve acceptable results, and our proposed model performed slightly better than the model in [35].”
    Quote in the paperSubstantial claim0 of 1 sources checked
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    Findingown data
    § C. Electrical Circuit Model Extraction Results

    R_i values were almost irrespective of current rate and direction and switch on/off phases, but depended on SOC, temperature, as well as SOH.

    “Conclusion could be derived that: R i values were almost irrespective of current rate and direct ion and switch on/off phases, but depended on SOC, T, as well as SOH.”
    Quote in the paperSubstantial claim
  • May combine two claims.

    Findingown data
    § A. Verification of the Terminal Voltage Prediction

    U_offset (about 11 mV), modeled as a linear function, decayed much more slowly and vanished in about 1.7 hours.

    “U offset (about 11 mV), which was modeled as a linear function in the proposed model, decayed much more slowly and vanished in about 1.7 hours.”
    Quote in the paperNot a substantial claim
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    Findingown data
    § C. Electrical Circuit Model Extraction Results

    As the battery aged progressively, R_f and R_s increased on the whole, and the dependence on SOC was more pronounced.

    “As the battery aged progressively, R f and R s increased on the whole, and the dependence on SOC was mo re pronounced.”
    Quote in the paperSubstantial claim
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    Findingown data
    § C. Electrical Circuit Model Extraction Results

    The parameters under charge and discharge regimes were not equal to each other and varied with different SOCs and load current rate.

    “It could be seen that the parameters under charge and discharge regimes were not equal to each other and they varied with different SOCs and load current rate.”
    Quote in the paperSubstantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation
    § I. INTRODUCTION

    Li-ion rechargeable batteries are the most promising energy storage solution due to high gravimetric and volumetric energy density, great cycle life, enhanced safety and low self-discharge rate.

    “A mong all the energy storage techniques, Li-ion based rechargeable batteries are deemed to be the most promising solution, due to their outperformed perfo rmance such as high gravimetric and volumetric energy density, great cycle life, enhanced safety and low self-discharge rate [1][2][3].”
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    Premisecitation
    § I. INTRODUCTION

    SOE was introduced in 2010 to directly delineate the energy state of batteries.

    “SOE was introduced in 2010 to directly delineate the energy state of batteries [12,13]”
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    Premisecitation
    § I. INTRODUCTION

    SOC represents the capacity state rather than the energy state, so it is no longer sufficient to describe battery behavior in ESS applications where residual energy rather than residual capacity is essential.

    “However, since SOC represents the capacity state instead of the energy state, it is no longer sufficient to describe the battery behavior in the ESS applications where the residual energy rather than the residual capacity of batteries is essential [4].”
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    Premisecitation
    § I. INTRODUCTION

    Neural-network-based SOE prediction methods' estimation exactness highly depended on the training data provided, and their systematic complexity needed to be decreased to reduce hardware costs.

    “In [4,14], neural networks were used to predict the battery SOE variation, but the estimat ion exactness highly depended on the training data provided and the systematic co mplexity needed to be decreased to reduce the hardware costs.”
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    Premisecitation
    § I. INTRODUCTION

    Online SOE estimators using filters achieved acceptable results, but their intricate filtering algorithms produced heavy computational burdens for BMS microprocessors with limited computational capability.

    “These online estimators achieved acceptable results, but the intricate filtering algorith m produced heavy computational burdens for the micro-processors in the BMSs, wh ich were always with limited co mputational capability.”
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    Interpretationcitation
    § A. Electrical Circuit Battery Model

    Due to intrinsic peculiarities of ECMs, there is deficiency in capturing non-linear battery behaviors induced by load variations, which will undermine SOE estimation accuracy if ECMs work alone under strenuous loads.

    “Additionally, due to the intrinsical peculiarities of ECMs, there is some deficiency in capturing the non -linear battery behaviors induced by the load variations and will undermine the SOE estimation accuracy if ECMs work alone under strenuous loads.”
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    Premisecitation
    § I. INTRODUCTION

    All above-mentioned research works only focused on SOE estimation and did not involve prediction of voltage responses of batteries; in online SOE estimators, voltage responses were taken as input factors.

    “Last but not least, unfortunately, all of the above-mentioned research works only focused on the estimat ion of SOE but did not involve the prediction of the voltage responses of batteries: in the online SOE estimators [15][16][17][18][19][20][21], the voltage responses were taken as input factors.”
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    Interpretationreasoning
    § D. Innovation and Enhancement of Proposed Method

    The proposed method was capable of improving the model accuracy and offering a good trade-off between the model accuracy and computational burden.

    “In conclusion, the proposed method was capable of improving the model accuracy and offering a good trade-off between the model accuracy and computational burden.”
    Quote in the paperSubstantial claim
  • May combine two claims.

    Interpretationreasoning
    § B. State of Energy

    Battery SOH, ambient temperature, and load conditions all influence discharging performance, inducing quantitative change of RAE and MAE and further SOE.

    “The battery SOH, amb ient temperature, and load conditions would all influence the discharging performance thus inducing quantitative change of RA E and MA E and further the SOE.”
    Quote in the paperSubstantial claim
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    Interpretationown data
    § C. Extraction of Impedance Parameters

    Introducing Uoffset increases model accuracy but keeps the additional increase of computational complexity to a minimal level.

    “This would increase the model accuracy but keep the additional increase of the computational complexity to a minimal level.”
    Quote in the paperSubstantial claim
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    Interpretationreasoning
    § B. Proposed Model and Work flow

    The proposed generic modeling method is concise but useful since it allowed accurate online prediction of battery performance using data gleaned from laboratory-scale tests.

    “This proposed generic modeling method was concise but useful since it allowed accurate online prediction of battery performance using data gleaned fro m the laboratoryscale tests.”
    Quote in the paperSubstantial claim
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    Interpretationreasoning
    § D. Innovation and Enhancement of Proposed Method

    Prolonged rest time guaranteed the battery to completely reach equilibrium, thus the entire transient voltage could be captured, and the accuracy was improved.

    “This prolonged rest time guaranteed the battery to completely reach equilibriu m thus the entire transient voltage could be captured, and the accuracy was improved.”
    Quote in the paperSubstantial claim
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    Premisecitation
    § I. INTRODUCTION

    Lin et al.'s multi-model-probability-based SOE estimation kept the weights of each model the same under dynamic loads for simplicity, resulting in little improvement in SOE estimation.

    “Additionally, Lin et al. [22] proposed a mu lti-model-p robability-based approach to jointly estimate the battery SOE.Be that it might be, the weights of each model were kept the same under dynamic loads for simplicity, resulting in that the SOE estimation results achieved little improvement.”
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    Study design and conductnone given
    § D. Innovation and Enhancement of Proposed Method

    The pulse test profile was optimized, and R_i values were calculated at a higher resolution from more SOCs in both charge and discharge directions and switch on/off phases.

    “Thirdly, the pulse test profile was optimized, and R i values were calculated at a higher resolution fro m mo re SOCs in both charge and directions and switch on/off phases.”
    Quote in the paperSubstantial claim
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    Interpretationown data
    § D. Innovation and Enhancement of Proposed Method

    The interval of rest time between current pulses should be 2 hours instead of the short idle time of 5-60 minutes because there was still some voltage variation after 1 hour's rest.

    “In supplement, due to the fact that there was still some voltage variation after 1 hour's rest in the idle period, the interval of the rest time between current pulses was advocated to be 2 hours, instead of the short idle t ime of 5 -60 minutes.”
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    Interpretationreasoning
    § D. Innovation and Enhancement of Proposed Method

    This work advocates equations (16) and (17) for R_f and R_s through the V-I values at t_pe, when the pulse current just began to fall.

    “In this work, we advocated ( 16) and ( 17) for R f and R s through the V-I values at t pe instead, when the pulse current just began to fall.”
    Quote in the paperSubstantial claim
  • Probably not a substantial claim: may not pass S2 (checkable), S3 (load-bearing), S4 (based). May combine two claims.

    Interpretationnone given
    § D. Innovation and Enhancement of Proposed Method

    The proposed approach had good generality and was highly versatile to simulate any cell materials without deep insights into the chemistry itself.

    “This proposed approach had good generality and were highly versatile to simulate any cell materials without deep insights into the chemistry itself.”
    Quote in the paperNot a substantial claim
  • May combine two claims.

    Premisecitation
    § I. INTRODUCTION

    SOE estimation algorithms that extract the relationship between SOC and SOE had accuracy totally dependent on estimated SOC results, and their estimated SOE results were merely verified at load current no more than 1.0 C.

    “However, the SOE estimat ion accuracy of these algorithms were totally dependent on the estimated SOC results, and the estimated SOE results were merely verified at load current of no mo re than 1.0 C.”
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    Interpretationreasoning
    § B. Proposed Model and Work flow

    The proposed SOE determination approach took thorough consideration of all influencing factors on discharging performance and further online SOE.

    “This proposed SOE determination approach took thorough consideration on all the influencing factors on the discharging performance and further the online SOE of batteries.”
    Quote in the paperNot a substantial claim
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    Interpretationown data
    § VII. CONCLUSION

    Following previous studies on online SOC and SOH co-evaluation, this work provides a holistic understanding on the discharging behavior, terminal voltage and online SOE variation of Li-ion batteries exploited as ESSs in smart grids.

    “Follo wing our previous studies on the online SOC and SOH co-evaluation of Li-ion batteries, this work provides a holistic understanding on the discharging behavior, terminal voltage and online SOE variation of Li-ion batteries explo ited as ESSs in smart grids.”
    Quote in the paperSubstantial claim
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    Study design and conductreasoning
    § B. Verification of Battery SOE and Runtime Estimation

    The actual SOE values were obtained through brute force according to the determining equation in (1).

    “It was worth noting that SOE results obtained from any algorith ms had errors more or less; thus, in this work, the actual SOE values were obtained through brute force according to the determining equation in (1).”
    Quote in the paperSubstantial claim
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    Interpretationnone given
    § VII. CONCLUSION

    A novel method to extract the parameters of the electrical model is proposed and it is capable of identifying the parameters with outperformed fidelity and acceptable computational burden.

    “In specific, the key contributions of this work are summarized as: (1) a novel method to ext ract the parameters of the electrical model is proposed and it is capable of identifying the parameters with outperformed fidelity and acceptable co mputational burden;”
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    Interpretationreasoning
    § VII. CONCLUSION

    The proposed model is based on Matlab/Simulink and computationally light, thus it has the potential to be implemented in the BMSs of the ESSs in the smart grids applications.

    “Last but not least, the proposed model is based on Matlab/Simulink and computationally light, thus it has the potential to be implemented in the BMSs of the ESSs in the s mart g rids applications.”
    Quote in the paperSubstantial claim
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    Interpretationown data
    § B. Verification of Battery SOE and Runtime Estimation

    The proposed model achieved a significant improvement over the previous model for estimating SOE, and was capable of predicting the SOE and runtime of an arbitrary aged cell under dynamic load and temperature conditions with high fidelity and reliability.

    “The test results denoted that the proposed model achieved a significant imp rovement over the previous model for estimating SOE, and it was capable of predict ing the SOE and runtime of an arbitrary aged cell under dynamic load and temperature conditions with h igh fidelity and reliability.”
    Quote in the paperSubstantial claim
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    Interpretationown data
    § VII. CONCLUSION

    Test results on commercial Li-ion batteries validated the robustness and effectiveness of the proposed battery model against varying load, temperature and battery ageing influences, comparing to most models in the literature that were only verified on fresh cells under moderate loads and from fully charged states.

    “(3) test results on commercial Li-ion batteries validated the robustness and effectiveness of the proposed battery model against varying load, temperature and battery ageing influences, comparing to that most models in the literature were only verified on fresh cells under moderate loads and from fully charged states.”
    Quote in the paperSubstantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Study design and conductnone given
    § B. Verification of Battery SOE and Runtime Estimation

    The brute-force method for obtaining actual SOE was a little bit time-consuming, but the results were almost 100% accurate.

    “This method was a little bit time-consuming, but the results were almost 100% accurate.”
    Quote in the paperNot a substantial claim
47 of 47
  • The paper relies on this without support.

    There existed only a few literatures on SOE estimation compared to SOC estimation.

    “Co mpared to the SOC estimation, there existed only a few literatures on SOE estimation.”
  • The paper relies on this without support.

    To date there is no unified determining equations for SOE.

    “Firstly, to date there is no unified determin ing equations for SOE.”
  • The paper relies on this without support.

    Most studies failed to obtain desirable SOE estimation against varying loads, ambient temperature and battery ageing conditions.

    “What's worse, most studies failed to obtain desirable SOE estimation against varying loads, ambient temperature and battery ageing conditions.”
  • The authors state this as an assumption.

    The SOH and initial SOC of the battery were already known.

    “Herein we assumed that the SOH and initial SOC were already known.”
  • The authors state this as an assumption.

    The expressions in (14) and (15) were also applicable at tpe when the load current just started to fall.

    “Since t pe was only 1.0 s before the t ime of t 0 , we could assume that the expression in ( 14) and (15) were also applicable at t pe when the load current just started to fall.”
  • The authors state this as an assumption.

    The fast and slow dynamics were both modeled as RC combinations.

    “Because the fast and slow dynamics were both modeled as RC combinations, the following expressions could be stated:”
  • The paper relies on this without support.

    All model parameters are multi-variable functions of SOC, current direction and rate, ambient temperature, self-discharge rate, hysteresis effects, and ageing levels of the batteries.

    “Theoretically, all of the model parameters are mu lti-variab le functions of SOC, current direction and rate, amb ient temperature, self-d ischarge rate, hysteresis effects, and ageing levels of the batteries.”
  • The paper relies on this without support.

    Electrical circuit models are among the most suitable candidates for battery parameters and terminal voltage prediction.

    “Being the most intuitive and facile to handle, electrical circuit models (ECMs) have been pervasively used in circuit simu lators and alongside applications, and they are among the most suitable candidates for battery parameters and terminal voltage prediction.”
  • The paper relies on this without support.

    Self-discharge can be ignored without noticeable effects on model accuracy.

    “The batteries used in this study had hysteresis of no mo re than 2 mV [31][32][33] and were cycled regularly, thus hysteresis and self-discharge were ignored without any noticeable effects on model accuracy.”
  • The paper relies on this without support.

    In smart grid applications, Li-ion batteries would scarcely be operated below 10% SOC.

    “In the smart grid applications, Li -ion batteries would scarcely be operated below 10% SOC, thus the voltage disparities in this region was of trivial significance.”
  • The paper relies on this without support.

    MAE is irrespective of the online SOC of the cell.

    “In supplement, the MAE of the cell was extracted by interpolating the MAE look-up tables in the proposed model according to the online load current rate, temperature and SOH, since MAE was irrespective of the online SOC of the cell.”
11 of 11

Self-check

Percentages, sums and reported differences re-computed from the paper’s own numbers.

Each contradiction between two passages listed here was confirmed by an independent check.

  • Conclusion understates the reported SOE error

    Major

    The conclusion says the SOE error was no more than 4.7%, but the validation section reports a 9.2% maximum absolute percentage error for the proposed model. The 4.7% figure is its RMS percentage error, not an upper bound on the error.

  • Incorrect 1.0 C RAE ratio in Table II

    Minor

    At 1.0 C, the listed RAE values are 17.2 and 45.5. Their ratio is 37.8%, not the reported 38.8%.

    Reported 38.8 · recomputed 37.802198

  • Reported maximum voltage error is below the RMS error

    Minor

    A maximum absolute percentage error cannot be smaller than the root mean square percentage error calculated from the same voltage errors. The reported maximum is 0.17%, while the RMS value is 0.23%.

3 of 3

Cites

Flagged first, then by citations

Cited by

Sorted by citations

Authors
Li, K., Wei, F., Tseng, K. J., & Soong, B.-H.
Affiliations
  • Nanyang Technological University (SG)
  • Singapore Institute of Technology (SG)
Venue
IEEE Transactions on Industrial Electronics
Published
2018-08
Volume
65
Issue
8
Pages
6696-6708
ISSN
  • 0278-0046 (ISSN-L)
  • 1557-9948
OpenAlex
W2774519208
Cited by
160
References
39
Citations by year
2026: 6 · 2025: 19 · 2024: 26 · 2023: 17 · 2022: 25 · 2021: 30 · 2020: 21 · 2019: 12 · 2018: 4
FWCI
6.41
Type
journal article
Language
en
Open access
Locations
  • IEEE Transactions on Industrial Electronics (publishedVersion)
  • DR-NTU (Nanyang Technological University) (submittedVersion)
Funders
  • National Research Foundation
  • National Research Foundation Singapore
Topics
  • Physical Sciences › Engineering › Automotive Engineering › Advanced Battery Technologies Research
  • Physical Sciences › Engineering › Electrical and Electronic Engineering › Advancements in Battery Materials
  • Physical Sciences › Energy › Energy Engineering and Power Technology › Power Systems and Renewable Energy
Keywords
state of energy estimation, terminal voltage prediction, battery degradation, operating temperature effects, dynamic loading, battery energy storage, smart grid

About these checks

Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.

Claims read by deepseek-v4.1-flash under definition version 3 (extract-v3) on 2026-10-09.

Classified by jev-1.13-20260917 (gold-guideline-v0.2) on 2026-10-09.

Statistics and arithmetic are recomputed, not judged.

Confidence bands are shown only for fields calibrated on our annotated test set. None is calibrated yet, so no band is shown.

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