scholarly journals Battery State Estimation with ANN and SVR Evaluating Electrochemical Impedance Spectra Generalizing DC Currents

2021 ◽  
Vol 12 (1) ◽  
pp. 274
Author(s):  
Andre Loechte ◽  
Ignacio Rojas Ruiz ◽  
Peter Gloesekoetter
Keyword(s):  
Electrochemical Impedance Spectroscopy ◽  
Energy Density ◽  
Impedance Spectroscopy ◽  
Electrochemical Impedance ◽  
Ambient Air ◽  
High Energy ◽  
The State ◽  
State Of Charge ◽  
High Energy Density ◽  
Impedance Spectra

The demand for energy storage is increasing massively due to the electrification of transport and the expansion of renewable energies. Current battery technologies cannot satisfy this growing demand as they are difficult to recycle, as the necessary raw materials are mined under precarious conditions, and as the energy density is insufficient. Metal–air batteries offer a high energy density as there is only one active mass inside the cell and the cathodic reaction uses the ambient air. Various metals can be used, but zinc is very promising due to its disposability and non-toxic behavior, and as operation as a secondary cell is possible. Typical characteristics of zinc–air batteries are flat charge and discharge curves. On the one hand, this is an advantage for the subsequent power electronics, which can be optimized for smaller and constant voltage ranges. On the other hand, the state determination of the system becomes more complex, as the voltage level is not sufficient to determine the state of the battery. In this context, electrochemical impedance spectroscopy is a promising candidate as the resulting impedance spectra depend on the state of charge, working point, state of aging, and temperature. Previous approaches require a fixed operating state of the cell while impedance measurements are being performed. In this publication, electrochemical impedance spectroscopy is therefore combined with various machine learning techniques to also determine successfully the state of charge during charging of the cell at non-fixed charging currents.

scholarly journals Variable-Order Equivalent Circuit Modeling and State of Charge Estimation of Lithium-Ion Battery Based on Electrochemical Impedance Spectroscopy

Energies ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 769
Author(s):  
Ji’ang Zhang ◽  
Ping Wang ◽  
Yushu Liu ◽  
Ze Cheng
Keyword(s):  
Electrochemical Impedance Spectroscopy ◽  
Impedance Spectroscopy ◽  
Equivalent Circuit ◽  
Electrochemical Impedance ◽  
Equivalent Circuit Model ◽  
Lithium Ion ◽  
Impedance Spectrum ◽  
The State ◽  
State Of Charge ◽  
Variable Order

In the battery management system, it is important to accurately and efficiently estimate the state of charge (SOC) of lithium-ion batteries, which generally requires the establishment of a equivalent circuit model of the battery, whose accuracy and rationality play an important role in accurately estimating the state of lithium-ion batteries. The traditional single order equivalent circuit models do not take into account the changes of impedance spectrum under the action of multiple factors, nor do they take into account the balance of practicality and complexity of the model, resulting the low accuracy and poor practicability. In this paper, the theory of electrochemical impedance spectroscopy is used to guide and improve the equivalent circuit model. Based on the analysis of the variation of the high and intermediate frequency range of the impedance spectrum with the state of charge and temperature of the battery, a variable order equivalent model (VOEM) is proposed by Arrhenius equation and Bayesian information criterion (BIC), and the state equation and observation equation of VOEM are improved by autoregressive (AR) equations. Combined with the unscented Kalman filter (UKF), a SOC online estimation method is proposed, named VOEM-AR-UKF. The experimental results show that the proposed method has high accuracy and good adaptability.

scholarly journals A Review of Size Engineering-Enabled Electrocatalysts for Li–S Chemistry

2021 ◽  
Author(s):  
Xi Zhang ◽  
Yaping Zhang ◽  
xijun wei ◽  
Chaohui Wei ◽  
Yingze Song
Keyword(s):  
Energy Density ◽  
High Energy ◽  
The State ◽  
High Energy Density ◽  
State Of Art

Li–S batteries (LBSs) have received extensive attention owing to their remarkable theoretical capacity (1672 mA h g–1) and high energy density (2600 Wh kg–1), far beyond the state of art...

Use and misuse of electrochemical impedance spectroscopy in PEFC research

2019 ◽  
Author(s):  
Pierre Boillat ◽  
Lorenz Gubler ◽  
Felix N. Büchi ◽  
Thomas J. Schmidt
Keyword(s):  
Fuel Cells ◽  
Electrochemical Impedance Spectroscopy ◽  
Impedance Spectroscopy ◽  
Polymer Electrolyte ◽  
Electrochemical Impedance ◽  
Polymer Electrolyte Fuel Cells ◽  
Impedance Spectra ◽  
Electrochemical Impedance Spectra ◽  
Comprehensive Review ◽  
Research Show

In this presentation, two important pitfalls ocuring during the analysis of electrochemical impedance spectra (EIS) of polymer electrolyte fuel cells (PEFCs) are discussed. Based on very simple considerations, some commonly found interpretation statements are identified as wrong. A comprehensive review of the papers published during the year 2018 using EIS in PEFC research show that such wrong statements are not occasional, but frequently occurring in the peer reviewed literature. At the end of the presentation, solution are proposed to increase the awareness to the risks of wrong EIS interpretations.

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