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Zinc-air batteries could be a key technology for higher energy densities of electrochemical energy storage systems. Many questions remain unanswered, however, and new methods for analyses and quantifications are needed. In this study, the distribution of relaxation times (DRT) based on ridge regression was applied to the impedance data of primary zinc-air batteries in a temperature range of 253 K and 313 K and at different State-of-Charges for the first time. Furthermore, the problem of the regularization parameter on real impedance spectroscopic measurements was addressed and a method was presented using the reconstruction of impedance data from the DRT as a quality criterion. The DRT was able to identify a so far undiscussed process and thus explain why some equivalent circuit models may fail.
Robert Franke-Lang; Julia Kowal. Analysis of Electrochemical Impedance Spectroscopy on Zinc-Air Batteries Using the Distribution of Relaxation Times. Batteries 2021, 7, 56 .
AMA StyleRobert Franke-Lang, Julia Kowal. Analysis of Electrochemical Impedance Spectroscopy on Zinc-Air Batteries Using the Distribution of Relaxation Times. Batteries. 2021; 7 (3):56.
Chicago/Turabian StyleRobert Franke-Lang; Julia Kowal. 2021. "Analysis of Electrochemical Impedance Spectroscopy on Zinc-Air Batteries Using the Distribution of Relaxation Times." Batteries 7, no. 3: 56.
The distribution of relaxation times (DRT) analysis of impedance spectra is a proven method to determine the number of occurring polarization processes in lithium-ion batteries (LIBs), their polarization contributions and characteristic time constants. Direct measurement of a spectrum by means of electrochemical impedance spectroscopy (EIS), however, suffers from a high expenditure of time for low-frequency impedances and a lack of general availability in most online applications. In this study, a method is presented to derive the DRT by evaluating the relaxation voltage after a current pulse. The method was experimentally validated using both EIS and the proposed pulse evaluation to determine the DRT of automotive pouch-cells and an aging study was carried out. The DRT derived from time domain data provided improved resolution of processes with large time constants and therefore enabled changes in low-frequency impedance and the correlated degradation mechanisms to be identified. One of the polarization contributions identified could be determined as an indicator for the potential risk of plating. The novel, general approach for batteries was tested with a sampling rate of 10 Hz and only requires relaxation periods. Therefore, the method is applicable in battery management systems and contributes to improving the reliability and safety of LIBs.
Erik Goldammer; Julia Kowal. Determination of the Distribution of Relaxation Times by Means of Pulse Evaluation for Offline and Online Diagnosis of Lithium-Ion Batteries. Batteries 2021, 7, 36 .
AMA StyleErik Goldammer, Julia Kowal. Determination of the Distribution of Relaxation Times by Means of Pulse Evaluation for Offline and Online Diagnosis of Lithium-Ion Batteries. Batteries. 2021; 7 (2):36.
Chicago/Turabian StyleErik Goldammer; Julia Kowal. 2021. "Determination of the Distribution of Relaxation Times by Means of Pulse Evaluation for Offline and Online Diagnosis of Lithium-Ion Batteries." Batteries 7, no. 2: 36.
The electrification of the powertrain requires enhanced performance of lithium-ion batteries, mainly in terms of energy and power density. They can be improved by optimising the positive electrode, i.e., by changing their size, composition or morphology. Thick electrodes increase the gravimetric energy density but generally have an inefficient performance. This work presents a 2D modelling approach for better understanding the design parameters of a thick LiFePO4 electrode based on the P2D model and discusses it with common literature values. With a superior macrostructure providing a vertical transport channel for lithium ions, a simple approach could be developed to find the best electrode structure in terms of macro- and microstructure for currents up to 4C. The thicker the electrode, the more important are the direct and valid transport paths within the entire porous electrode structure. On a smaller scale, particle size, binder content, porosity and tortuosity were identified as very impactful parameters, and they can all be attributed to the microstructure. Both in modelling and electrode optimisation of lithium-ion batteries, knowledge of the real microstructure is essential as the cross-validation of a cellular and lamellar freeze-casted electrode has shown. A procedure was presented that uses the parametric study when few model parameters are known.
Robert Franke-Lang; Julia Kowal. Electrochemical Model-Based Investigation of Thick LiFePO4 Electrode Design Parameters. Modelling 2021, 2, 259 -287.
AMA StyleRobert Franke-Lang, Julia Kowal. Electrochemical Model-Based Investigation of Thick LiFePO4 Electrode Design Parameters. Modelling. 2021; 2 (2):259-287.
Chicago/Turabian StyleRobert Franke-Lang; Julia Kowal. 2021. "Electrochemical Model-Based Investigation of Thick LiFePO4 Electrode Design Parameters." Modelling 2, no. 2: 259-287.
This article presents a novel approach to extract the equivalent circuit model parameter from a pulse test. The presented results corroborate that this novel heuristic methodology can very accurately fit the voltage response of the battery, while drastically reducing the dependence of the parametrization on set boundary conditions and initial guess values. The method's robustness is verified by fitting the voltage response of a mock battery model with pre-defined parameters. It could be shown that the suggested method is able to precisely extract the set parameters from the simulated voltage. Furthermore, the model values obtained from the test of a lithium ion battery cell correlate with physical parameter and other investigation methods like the calculation of the distribution of relaxation times (DRT). As a result, an accurate equivalent circuit model of the cell was created. The restriction as to universal validity of the empirical equivalent circuit model was significantly reduced by limiting the voltage of the RC element with highest time constant. Finally, a robust battery cell model with only a minor root-mean-square error of 1.30% was obtained. A new method for the precise parameterization of an equivalent circuit model from pulse tests is presented. The robustness of such equivalent circuit models is increased by limiting the voltage of the RC element with the highest time constant. Overall, a precise, reliable model of a lithium-ion battery cell is created.
Maximilian Bruch; Lluis Millet; Julia Kowal; Matthias Vetter. Novel method for the parameterization of a reliable equivalent circuit model for the precise simulation of a battery cell's electric behavior. Journal of Power Sources 2021, 490, 229513 .
AMA StyleMaximilian Bruch, Lluis Millet, Julia Kowal, Matthias Vetter. Novel method for the parameterization of a reliable equivalent circuit model for the precise simulation of a battery cell's electric behavior. Journal of Power Sources. 2021; 490 ():229513.
Chicago/Turabian StyleMaximilian Bruch; Lluis Millet; Julia Kowal; Matthias Vetter. 2021. "Novel method for the parameterization of a reliable equivalent circuit model for the precise simulation of a battery cell's electric behavior." Journal of Power Sources 490, no. : 229513.
A dataset consisting of 90 lithium-ion cells obtained from old notebook batteries containing their response to 100 charge–discharge cycles is presented. The resulting degradation patterns are assigned to four clusters and related to possible aging mechanisms. The records in the battery management system (BMS) of each battery are analyzed to understand the influence of first life conditions in the measured degradation patterns. The analysis reveals that a cluster of cells which experienced mostly calendar aging in 7–13 years hold ~90% of the rated capacity, and exhibit at 0.4 C discharge a linear capacity degradation throughout cycling comparable to new cells. In contrast, a cluster of cells that experienced extensive calendar and cyclic aging can lose ~50% capacity at 0.4 C discharge in a few cycles after reutilization. A model based on a boosted decision tree is applied to forecast the cluster of each cell, using as features the capacity measured in the first cycle, and the records obtained from the BMS. The highest accuracy (83%) is obtained through capacity, where misclassification arises from two clusters containing highly degraded cells with similar initial capacities, but divergent degradation patterns.
Felipe Salinas; Julia Kowal. Classifying Aged Li-Ion Cells from Notebook Batteries. Sustainability 2020, 12, 3620 .
AMA StyleFelipe Salinas, Julia Kowal. Classifying Aged Li-Ion Cells from Notebook Batteries. Sustainability. 2020; 12 (9):3620.
Chicago/Turabian StyleFelipe Salinas; Julia Kowal. 2020. "Classifying Aged Li-Ion Cells from Notebook Batteries." Sustainability 12, no. 9: 3620.
Modern battery energy systems are key enablers of the conversion of our energy and mobility sector towards renewability. Most of the time, their batteries are connected to power electronics that induce high frequency current ripple on the batteries that could lead to reinforced battery ageing. This study investigates the influence of high frequency current ripple on the ageing of commercially available, cylindrical 18,650 lithium-ion batteries in comparison to identical batteries that are aged with a conventional battery test system. The respective ageing tests that have been carried out to obtain numerous parameters such as the capacity loss, the gradient of voltage curves and impedance spectra are explained and evaluated to pinpoint how current ripple possibly affects battery ageing. Finally, the results suggest that there is little to no further influence of current ripple that is severe enough to stand out against ageing effects due to the underlying accelerated cyclic ageing.
Pablo Korth Pereira Ferraz; Julia Kowal. A Comparative Study on the Influence of DC/DC-Converter Induced High Frequency Current Ripple on Lithium-Ion Batteries. Sustainability 2019, 11, 6050 .
AMA StylePablo Korth Pereira Ferraz, Julia Kowal. A Comparative Study on the Influence of DC/DC-Converter Induced High Frequency Current Ripple on Lithium-Ion Batteries. Sustainability. 2019; 11 (21):6050.
Chicago/Turabian StylePablo Korth Pereira Ferraz; Julia Kowal. 2019. "A Comparative Study on the Influence of DC/DC-Converter Induced High Frequency Current Ripple on Lithium-Ion Batteries." Sustainability 11, no. 21: 6050.
The market of accumulator based technologies is changing very fast, especially the electro mobility market due to different decisions made to reduce the impact on climate change. In most markets battery packs are used, which means accumulators are connected to form a battery system consisting of, from a few accumulators up to thousands. Research of battery technologies often focuses on single cells, however considering the applications it is important to know the behaviour of different cells in a system. This paper deals with the inhomogeneities which influence the electrical behaviour of the system in simulation and measurement with a special focus on parallel connected cells.
Steven Neupert; Julia Kowal. Inhomogeneities in Battery Packs. World Electric Vehicle Journal 2018, 9, 20 .
AMA StyleSteven Neupert, Julia Kowal. Inhomogeneities in Battery Packs. World Electric Vehicle Journal. 2018; 9 (2):20.
Chicago/Turabian StyleSteven Neupert; Julia Kowal. 2018. "Inhomogeneities in Battery Packs." World Electric Vehicle Journal 9, no. 2: 20.
Alexander Börger; Ellen Ebner; Simon Calles; Heide Budde-Meiwes; Dominik Schulte; Julia Kowal; Dirk Uwe Sauer. Impedance spectra of enhanced flooded batteries for micro-hybrid applications. Journal of Energy Storage 2017, 13, 457 -462.
AMA StyleAlexander Börger, Ellen Ebner, Simon Calles, Heide Budde-Meiwes, Dominik Schulte, Julia Kowal, Dirk Uwe Sauer. Impedance spectra of enhanced flooded batteries for micro-hybrid applications. Journal of Energy Storage. 2017; 13 ():457-462.
Chicago/Turabian StyleAlexander Börger; Ellen Ebner; Simon Calles; Heide Budde-Meiwes; Dominik Schulte; Julia Kowal; Dirk Uwe Sauer. 2017. "Impedance spectra of enhanced flooded batteries for micro-hybrid applications." Journal of Energy Storage 13, no. : 457-462.
Grzegorz Piłatowicz; Heide Budde-Meiwes; Julia Kowal; Christel Sarfert; Eberhard Schoch; Martin Königsmann; Dirk Uwe Sauer. Determination of the lead-acid battery's dynamic response using Butler-Volmer equation for advanced battery management systems in automotive applications. Journal of Power Sources 2016, 331, 348 -359.
AMA StyleGrzegorz Piłatowicz, Heide Budde-Meiwes, Julia Kowal, Christel Sarfert, Eberhard Schoch, Martin Königsmann, Dirk Uwe Sauer. Determination of the lead-acid battery's dynamic response using Butler-Volmer equation for advanced battery management systems in automotive applications. Journal of Power Sources. 2016; 331 ():348-359.
Chicago/Turabian StyleGrzegorz Piłatowicz; Heide Budde-Meiwes; Julia Kowal; Christel Sarfert; Eberhard Schoch; Martin Königsmann; Dirk Uwe Sauer. 2016. "Determination of the lead-acid battery's dynamic response using Butler-Volmer equation for advanced battery management systems in automotive applications." Journal of Power Sources 331, no. : 348-359.
Temperature is an important impact factor for both battery performance and lifetime. As lifetime of a battery is typically smaller than that of the application it is used in and performance decreases significantly with ageing, lifetime and performance predictions are of great importance for almost all battery-powered applications. To achieve a good and reliable prediction, comprehensive ageing tests with a significant number of different operating conditions are necessary. From time to time, ageing tests are interrupted for capacity and resistance checkups. For comparable results, these checkups have to be performed under the same ambient conditions, typically room temperature. Thus, before the checkup is started, temperature equalisation is needed. The same is true for performance tests or parameterisation measurements for electrical models. Typically, they are not only performed at room temperature, but also at other temperatures to identify the influence of temperature on performance or electrical impedance. For this reason, a homogeneous temperature within the cell is essential for the test results as well. Therefore, a certain waiting time has to be inserted before starting the test, that on the one hand has to be long enough to assure that all parts of the battery have the same temperature, but on the other hand is as short as possible to prevent an unnecessary prolongation of the test, especially for already time consuming ageing tests. Temperature measurements within cells are typically impossible for commercial cells without destroying the cell. However, this paper shows that it is sufficient to measure the outside temperature to find out the necessary waiting time.
Julia Kowal; Arno Arzberger; Holger Blanke; Dirk Uwe Sauer. How to determine the time for temperature equalisation in batteries and supercaps for reliable laboratory measurements. Journal of Energy Storage 2015, 4, 113 -120.
AMA StyleJulia Kowal, Arno Arzberger, Holger Blanke, Dirk Uwe Sauer. How to determine the time for temperature equalisation in batteries and supercaps for reliable laboratory measurements. Journal of Energy Storage. 2015; 4 ():113-120.
Chicago/Turabian StyleJulia Kowal; Arno Arzberger; Holger Blanke; Dirk Uwe Sauer. 2015. "How to determine the time for temperature equalisation in batteries and supercaps for reliable laboratory measurements." Journal of Energy Storage 4, no. : 113-120.
Die Speicherung der elektrischen Energie im Fahrzeug und ihre bedarfsabhängige Abgabe gehören neben den elektrischen Maschinen (siehe auch Kapitel 2.2 und 2.3) und der Leistungselektronik (siehe Kapitel 4.1) zu den Schlüsseltechnologien für die Elektrifizierung des Antriebsstrangs. Die Batterie (genau gesprochen der Akkumulator wegen der Wiederaufladbarkeit) ist der heute üblicherweise eingesetzte Energiespeicher. Schon vor etwa 100 Jahren sind die damals dominierenden Elektrofahrzeuge an der Batterietechnik gescheitert. Die Batterien waren zu schwer, zu groß und hatten eine zu geringe Speicherkapazität. Die jahrzehntelange Entwicklung führte inzwischen zu Alternativen zur konventionellen Bleibatterie, wie der Nickel-Cadmium-, der Nickel-Metall- Hydrid- oder der Lithium-Ionen- Batterie. Nachfolgend werden die Grundlagen der Batterietechnik beschrieben. Die Lithium-Ionen-Batterie als besonders erfolgversprechende Entwicklung für den Fahrzeugeinsatz wird in Kapitel 3.2 vorgestellt.
Julia Drillkens; Madeleine Ecker; Julia Kowal; Dirk Uwe Sauer. Speicherung der elektrischen Energie. Die Elektrifizierung des Antriebsstrangs 2014, 51 -76.
AMA StyleJulia Drillkens, Madeleine Ecker, Julia Kowal, Dirk Uwe Sauer. Speicherung der elektrischen Energie. Die Elektrifizierung des Antriebsstrangs. 2014; ():51-76.
Chicago/Turabian StyleJulia Drillkens; Madeleine Ecker; Julia Kowal; Dirk Uwe Sauer. 2014. "Speicherung der elektrischen Energie." Die Elektrifizierung des Antriebsstrangs , no. : 51-76.
Alternativ zu Batterien (Folgen 7 und 8 dieser Reihe) steht für die Speicherung elektrischer Energie auch die Kondensatortechnologie zur Verfügung. Systematisch gesehen gehören elektrochemische Doppelschichtkondensatoren, auch Supercaps, Ultracaps oder Superkondensatoren genannt, zur Gruppe der Kondensatoren. Aufgrund ihres Aufbaus mit porösen Elektroden und gelösten Ionen in einem organischen Elektrolyten werden sie — in Analogie zum Aufbau von Batterien — oftmals aber auch den elektrochemischen Energiespeichern zugerechnet. Allerdings finden in Kondensatoren weder beim Laden noch beim Entladen elektrochemische Reaktionen und nur in sehr begrenztem Umfang chemische Reaktionen statt. Supercaps sind interessante Energiespeicher für alle Anwendungen, bei denen hohe Leistung und große Zyklenzahl gefordert sind. Allerdings verhindern die hohen Kosten eine breitere Einführung in vielen Anwendungen. In Einsatzfällen mit sehr hoher Zyklenzahl (möglichst mehr als ein Zyklus pro min) können sie ...
Julia Kowal; Julia Drillkens; Dirk Uwe Sauer. 9. Superkondensatoren elektrochemische Doppelschichtkondensatoren. MTZ - Motortechnische Zeitschrift 2013, 74, 158 -163.
AMA StyleJulia Kowal, Julia Drillkens, Dirk Uwe Sauer. 9. Superkondensatoren elektrochemische Doppelschichtkondensatoren. MTZ - Motortechnische Zeitschrift. 2013; 74 (2):158-163.
Chicago/Turabian StyleJulia Kowal; Julia Drillkens; Dirk Uwe Sauer. 2013. "9. Superkondensatoren elektrochemische Doppelschichtkondensatoren." MTZ - Motortechnische Zeitschrift 74, no. 2: 158-163.
Stationary battery energy storage systems are widely used for uninterruptible power supply systems. Furthermore, they are able to provide grid services. This leads to rising installed power and capacity. Lead-acid batteries provide one of the most mature and economically feasible solutions. Although this technology has been known and studied for more than 100 years, a further understanding of the different operating conditions is still obligatory for an efficient utilization of resources. The area of deep discharge has so far been mostly neglected in published research apart from fundamental material investigations. However, this condition will become more dominant in storage applications for renewable energy sources, UPS and off grid applications. The underlying study has been conducted to obtain a better understanding of deep discharge behavior of lead acid batteries. The results have been implemented in a semi-empiric battery model.
Tobias Blank; Julia Badeda; Julia Kowal; Dirk Uwe Sauer. Deep discharge behavior of lead-acid batteries and modeling of stationary battery energy storage systems. Intelec 2012 2012, 1 -4.
AMA StyleTobias Blank, Julia Badeda, Julia Kowal, Dirk Uwe Sauer. Deep discharge behavior of lead-acid batteries and modeling of stationary battery energy storage systems. Intelec 2012. 2012; ():1-4.
Chicago/Turabian StyleTobias Blank; Julia Badeda; Julia Kowal; Dirk Uwe Sauer. 2012. "Deep discharge behavior of lead-acid batteries and modeling of stationary battery energy storage systems." Intelec 2012 , no. : 1-4.
A microcontroller-based device has been developed for continuous measurement of current distribution and acid stratification in commercial flooded lead-acid batteries. Acid density at four different levels is measured using micro reference cells and the current density is determined from potential drops along the grid. The measurement method, the full device and measurement results are presented and discussed.
Dominik Schulte; Tilman Sanders; Wladislaw Waag; Julia Kowal; Dirk Uwe Sauer; Eckhard Karden. Automatic device for continuous measurement of potential distribution and acid stratification in flooded lead-acid batteries. Journal of Power Sources 2012, 221, 114 -121.
AMA StyleDominik Schulte, Tilman Sanders, Wladislaw Waag, Julia Kowal, Dirk Uwe Sauer, Eckhard Karden. Automatic device for continuous measurement of potential distribution and acid stratification in flooded lead-acid batteries. Journal of Power Sources. 2012; 221 ():114-121.
Chicago/Turabian StyleDominik Schulte; Tilman Sanders; Wladislaw Waag; Julia Kowal; Dirk Uwe Sauer; Eckhard Karden. 2012. "Automatic device for continuous measurement of potential distribution and acid stratification in flooded lead-acid batteries." Journal of Power Sources 221, no. : 114-121.
Impedance measurements of both electrodes of a flooded OEM SLI battery at various SOC and with various direct currents have been measured. For each part of the impedance spectra, an electrochemical process is proposed and implemented in a simulation model. By simulation of impedance spectroscopy, spectra of the model are obtained and compared with the measurement. In the first part, the focus was put on inductive semicircles, while in this second part, concentration limitation and its appearance in impedance spectra is investigated.
Julia Kowal; Heide Budde-Meiwes; Dirk Uwe Sauer. Interpretation of processes at positive and negative electrode by measurement and simulation of impedance spectra. Part II: Concentration limitation. Journal of Power Sources 2012, 207, 45 -50.
AMA StyleJulia Kowal, Heide Budde-Meiwes, Dirk Uwe Sauer. Interpretation of processes at positive and negative electrode by measurement and simulation of impedance spectra. Part II: Concentration limitation. Journal of Power Sources. 2012; 207 ():45-50.
Chicago/Turabian StyleJulia Kowal; Heide Budde-Meiwes; Dirk Uwe Sauer. 2012. "Interpretation of processes at positive and negative electrode by measurement and simulation of impedance spectra. Part II: Concentration limitation." Journal of Power Sources 207, no. : 45-50.
Dynamic charge acceptance (DCA) is a key requirement for batteries in micro-hybrid vehicles. In automotive applications, DCA reaches a stable level during several weeks or months in service. A conditioning method that accelerates stabilizing DCA is presented. Various test methods for evaluation of DCA are compared. This is necessary for comparing new technologies (e.g. negative electrodes with carbon additives) and cell concepts (e.g. bi-polar batteries).
Heide Budde-Meiwes; Dominik Schulte; Julia Kowal; Dirk Uwe Sauer; Ralf Hecke; Eckhard Karden. Dynamic charge acceptance of lead–acid batteries: Comparison of methods for conditioning and testing. Journal of Power Sources 2012, 207, 30 -36.
AMA StyleHeide Budde-Meiwes, Dominik Schulte, Julia Kowal, Dirk Uwe Sauer, Ralf Hecke, Eckhard Karden. Dynamic charge acceptance of lead–acid batteries: Comparison of methods for conditioning and testing. Journal of Power Sources. 2012; 207 ():30-36.
Chicago/Turabian StyleHeide Budde-Meiwes; Dominik Schulte; Julia Kowal; Dirk Uwe Sauer; Ralf Hecke; Eckhard Karden. 2012. "Dynamic charge acceptance of lead–acid batteries: Comparison of methods for conditioning and testing." Journal of Power Sources 207, no. : 30-36.
Impedance measurements of both electrodes of a flooded OEM SLI battery at various SOC and with various direct currents have been measured. For each part of the impedance spectra, an electrochemical process is proposed and implemented in a simulation model. By simulation of impedance spectroscopy, spectra of the model are obtained and compared with the measurement. In this first part, the focus is put on inductive semicircles in impedance spectra.
Julia Kowal; Heide Budde-Meiwes; Dirk Uwe Sauer. Interpretation of processes at positive and negative electrode by measurement and simulation of impedance spectra. Part I: Inductive semicircles. Journal of Power Sources 2012, 207, 10 -18.
AMA StyleJulia Kowal, Heide Budde-Meiwes, Dirk Uwe Sauer. Interpretation of processes at positive and negative electrode by measurement and simulation of impedance spectra. Part I: Inductive semicircles. Journal of Power Sources. 2012; 207 ():10-18.
Chicago/Turabian StyleJulia Kowal; Heide Budde-Meiwes; Dirk Uwe Sauer. 2012. "Interpretation of processes at positive and negative electrode by measurement and simulation of impedance spectra. Part I: Inductive semicircles." Journal of Power Sources 207, no. : 10-18.
Heide Budde-Meiwes; Julia Kowal; Dirk Uwe Sauer; Eckhard Karden. Influence of measurement procedure on quality of impedance spectra on lead–acid batteries. Journal of Power Sources 2011, 196, 10415 -10423.
AMA StyleHeide Budde-Meiwes, Julia Kowal, Dirk Uwe Sauer, Eckhard Karden. Influence of measurement procedure on quality of impedance spectra on lead–acid batteries. Journal of Power Sources. 2011; 196 (23):10415-10423.
Chicago/Turabian StyleHeide Budde-Meiwes; Julia Kowal; Dirk Uwe Sauer; Eckhard Karden. 2011. "Influence of measurement procedure on quality of impedance spectra on lead–acid batteries." Journal of Power Sources 196, no. 23: 10415-10423.
Spatially resolved simulation models are valuable tools to predict the behaviour (electrical, thermal, ageing) of energy storage systems. However, parameterisation of the electrical impedance-based model is often difficult because local measurements are hardly possible. For homogeneous conditions, e.g. homogeneous current, state of charge and temperature distribution, the measured overall impedance of a cell or electrode can be divided equally over the volume elements of the spatially resolved model. Homogeneous conditions are though very rare, so all larger devices show at least a current distribution because of non-zero ohmic resistances in current collectors, active masses and electrolyte. In this paper, a method is presented and validated for calculating the local impedance of nonlinear inhomogeneous devices from the overall impedance of the device. The method consists of iteration between impedance parameter identification and calculation of current distribution.
Julia Kowal; Dirk Uwe Sauer. Model parameterisation of nonlinear devices using impedance spectroscopy. Electrochimica Acta 2011, 56, 10107 -10115.
AMA StyleJulia Kowal, Dirk Uwe Sauer. Model parameterisation of nonlinear devices using impedance spectroscopy. Electrochimica Acta. 2011; 56 (27):10107-10115.
Chicago/Turabian StyleJulia Kowal; Dirk Uwe Sauer. 2011. "Model parameterisation of nonlinear devices using impedance spectroscopy." Electrochimica Acta 56, no. 27: 10107-10115.
Maximilian Kaus; Julia Kowal; Dirk Uwe Sauer. Modelling the effects of charge redistribution during self-discharge of supercapacitors. Electrochimica Acta 2010, 55, 7516 -7523.
AMA StyleMaximilian Kaus, Julia Kowal, Dirk Uwe Sauer. Modelling the effects of charge redistribution during self-discharge of supercapacitors. Electrochimica Acta. 2010; 55 (25):7516-7523.
Chicago/Turabian StyleMaximilian Kaus; Julia Kowal; Dirk Uwe Sauer. 2010. "Modelling the effects of charge redistribution during self-discharge of supercapacitors." Electrochimica Acta 55, no. 25: 7516-7523.