Optimization of the Perturbation Amplitude for EIS Measurements Using a Total Harmonic Distortion Based Method

Giner-Sanz, J.J.; Ortega, E.; Pérez-Herranz, V.

doi:10.1149/2.1021810jes

Cited by 15 publications

(17 citation statements)

References 89 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The SNR of the PRS is given by the length and the amplitude of the signal that together determine the power content of the signal. Increased amplitude of the PRS increases also the SNR, but this can introduce more nonlinear effects in the battery and can be even limited by the application [33]. The SNR can also be increased by shortening the sequence length, but this will reduce the bandwidth of the measurements by making the frequency resolution more sparse.…”

mentioning

confidence: 99%

Fast Approach for Battery Impedance Identification Using Pseudo-Random Sequence Signals

Sihvo

Stroe

Messo

et al. 2020

IEEE Trans. Power Electron.

102

View full text Add to dashboard Cite

Online measurements of the battery impedance provide valuable information on the battery state-of-charge and stateof-health, which can be utilized for improving the safety and the performance of the associated system. The electrochemicalimpedance spectroscopy (EIS) is widely used for battery impedance measurements, but it is not the most applicable solution for online measurements due to its slowness and complexity. These drawbacks can be improved using broadband signals, such as pseudorandom sequences (PRS), which are fast and easily implementable. However, the nonlinear behavior of batteries have a significant effect on the impedance measurements and the selection of the PRS signal. Majority of the PRS signals are applicable for measurements of linear systems, but also signals for nonlinear system identification do exist. Moreover, the reduced accuracy and signal-to-noise ratio of the PRS signals compared to the EIS make the filtering of the results as well as the amplitude design important aspects. This paper demonstrates the use of two PRS signals, the pseudorandom binary sequence (PRBS), and a ternary sequence with better toleration to battery nonlinear effects, with comprehensive amplitude and filtering design for battery impedance measurements. It is shown that the ternary sequence provides accurate measurements and the effects of nonlinear dynamics of the battery impedance are reduced with respect to the PRBS measurements. The results are referenced and validated to practical EIS measurements in various operating conditions for lithium-iron-phosphate (LiFePO 4 ) cell.

show abstract

mentioning

confidence: 99%

Fast Approach for Battery Impedance Identification Using Pseudo-Random Sequence Signals

Sihvo

Stroe

Messo

et al. 2020

IEEE Trans. Power Electron.

102

View full text Add to dashboard Cite

show abstract

“…At the EoD, the effect of the series inductance can be considered negligible. Thus, (2) can be reduced to (17), which can be written open and arranged in terms of R k CT as in (18) with the coefficients a R , b R , and c R given in (19). The coefficients can be applied to the quadratic equation to obtain a solution for R k CT .…”

Section: B Iterationmentioning

confidence: 99%

“…To meet these requirements, the amplitude is here chosen according to [24] where LiFePO4 battery of the same capacity, voltage and internal impedance magnitude was analyzed as in this work. The amplitude design yields to a current of 1.35A which is relatively small compared to the voltage response magnitude it introduces to the cell in the existing HPPC and EIS studies [3], [6], [18]- [20]. Therefore, the measured impedance spectra is filtered by the movingaverage-filter (MAF) in order to guarantee the smoothness of the impedance plot for the ECM fitting [24], [26].…”

Section: Impedance Measurementsmentioning

confidence: 99%

Novel Fitting Algorithm for Parametrization of Equivalent Circuit Model of Li-Ion Battery From Broadband Impedance Measurements

Sihvo

Roinila

Stroe

2021

IEEE Trans. Ind. Electron.

View full text Add to dashboard Cite

The impedance of Li-ion batteries contains information about the dynamics and state parameters of the battery. This information can be utilized to improve the performance and safety of the battery application. The battery impedance is typically modeled by an equivalentcircuit-model (ECM) which provides the dynamic information of the battery. In addition, the variations in the model parameters can be used for the battery state-estimation. A fitting algorithm is required to parametrize the ECM due to the non-linearity of both the battery impedance and ECM. However, conventional fitting algorithms, such as the complex-nonlinear-least-squares (CNLS) algorithm, often have a high computational burden and require selection of initial conditions which can be difficult to obtain adaptively. This paper proposes a novel fitting algorithm for the parametrization of battery ECM based on the geometric shape of the battery impedance in the complex-plane. The algorithm is applied to practical and fast broadband pseudo random sequence impedance measurements carried out at various state-of-charges (SOC) and temperatures for lithium-iron-phosphate cell. The performance of the method is compared to conventional CNLS algorithm with different initial conditions. The results show that the proposed method provides fast and accurate fit with low computational effort. Moreover, specific ECM parameters are found to be dependent on the battery SOC at various temperature. NOMENCLATURE CNLS Complex non-linear least squares ECM Equivalent circuit model. EIS Electrochemical impedance spectroscopy. EoD End of the diffusion. LiFePO4 Lithium iron phosphate. PRS Pseudo random sequence. NRMSE Normalized root mean square error. SEI Solid electrolyte interface SOC State of charge. SOH State of health. TSC Top of the semicircle. f gen Generation frequency of PRS. f res Frequency resolution of PRS measurements. C CT Capacitance of the charge-transfer region.

show abstract

“…For practical implementation, the sequences should have high SNR, which is determined by the sequence amplitude A and length N. The amplitude of the sequence is usually restricted by the application where the measurements are implemented. Moreover, the system nonlinear effects are increased with too high amplitudes, which is also the case for battery measurement [21]. Therefore, N offers a possibility to increase the SNR without adjusting the amplitude.…”

Section: Perturbation Designmentioning

confidence: 99%

Broadband Impedance Measurement of Lithium-Ion Battery in the Presence of Nonlinear Distortions

2020

View full text Add to dashboard Cite

The impedance of a Lithium-ion (Li-ion) battery has been shown to be a valuable tool in evaluating the battery characteristics such as the state-of-charge (SOC) and state-of-health (SOH). Recent studies have shown impedance-measurement methods based on broadband pseudo-random sequences (PRS) and Fourier techniques. The methods can be efficiently applied in real-time applications where the conventional electrochemical-impedance spectroscopy (EIS) is not well suited to measure the impedance. The techniques based on the PRS are, however, strongly affected by the battery nonlinearities. This paper presents the use of a direct-synthesis ternary (DST) signal to minimize the effect caused by the nonlinearities. In such a signal, the second- and third-order harmonics are suppressed from the signal energy spectrum. As a result, the effect of the second- and third-order nonlinearities are suppressed from the impedance measurements. The impedance measurements are carried out for a nickel manganese cobalt Li-ion battery cell. The performance of the method is compared to the conventional EIS, as well as to other PRS signals which are more prone to battery nonlinearities. The Kronig–Kramers (K–K) transformation test is used to validate the uniqueness of the measured impedance spectra. It is shown that the measurement method based on the DST produces highly accurate impedance measurements under nonlinear distortions of the battery. The method shows a good K–K test behavior indicating that the measured impedance complies well to a linearized equivalent circuit model that can be used for the SOC and SOH estimation of the battery. Due to the good performance, low measurement time, and simplicity of the DST, the method is well suited for practical battery applications.

show abstract

Optimization of the Perturbation Amplitude for EIS Measurements Using a Total Harmonic Distortion Based Method

Cited by 15 publications

References 89 publications

Fast Approach for Battery Impedance Identification Using Pseudo-Random Sequence Signals

Fast Approach for Battery Impedance Identification Using Pseudo-Random Sequence Signals

Novel Fitting Algorithm for Parametrization of Equivalent Circuit Model of Li-Ion Battery From Broadband Impedance Measurements

Broadband Impedance Measurement of Lithium-Ion Battery in the Presence of Nonlinear Distortions

Contact Info

Product

Resources

About