Mathematical Models and Methods for Lithiumion Batteries
In our modern age, where electronic devices are indispensable and electric vehicles are gaining momentum, the significance of efficient energy storage systems cannot be overstated. At the forefront of this energy revolution are lithiumion batteries, which allow for an efficient, lightweight, and safe storage of electrical energy. Their development was awarded the 2019 Nobel Prize in Chemistry and their further improvement to enhance energy storage capacity, safety, durability, and costeffectiveness, while also reducing reliance on rare materials and minimizing error rates, is a huge aspect in both research and industry.
Beneath the surface of these seemingly straightforward batteries lies a complex world of chemical reactions, electrochemical processes, and intricate material interactions. This is where mathematical modeling steps in as a vital tool to deepen our understanding of lithiumion batteries. Based on physical principles it is possible to understand their complex, nonlinear behavior and to predict their performance under a range of conditions. Mathematical modeling allows for virtual material design and testing and paves the way for their continuous improvement and optimization. This predictive power not only expedites the design and development of new battery technologies but also aids in the creation of strategies to enhance their efficiency, lifespan, and overall safety.
Lithiumion battery  scales
Lithiumion batteries span various spatial and temporal scales. The device which is commonly used in electric vehicles is termed battery module, which itself consists of multiple battery cells and a battery management system. The latter monitors, controls, and manages various aspects of the individual battery cells, for example the balancing of voltage and current among the cells during operation. A single battery cell is either a spiral wound or a stack of electrochemical unit cells, which consits of an anode, a seperator and a cathode. Each of these three phases is itself a porous medium with an individual microstructure and electrochemical performance. The porous electrodes, which consist of socalled active material particles kept together by some binding material as well as conductive additives, are soaked with electrolytes through which the transport of lithium ions is established. At each interface between an an electrode particle and the electrolyte an electrochemical double layer forms, where ions in the electrolyte and electrons on the surface of the electrode particle balance their charges. Resolving these double layers even further yields the actual electrode surfaces, on which the intercalation reaction Li^{+} + e^{} ⇌ Li occurs.
Lithiumion battery  functional principle
The anode and cathode materials of modern lithiumion batteries have the ability to host lithium within their crystal structure. The anode is typically made of graphite and when the battery is charged, lithium ions move from the cathode to the anode through the electrolyte. This process is called intercalation, and the intercalation reaction can be written as Li^{+} + e^{} + C_{6} ⇌ LiC_{6} . The cathode is usually made of a metal oxide, like lithium cobalt oxide (LiCoO_{2}), lithium iron phosphate (LiFePO_{4}) or LithiumNickelManganeseCobaltOxide ((Li(Ni_{x} Mn_{y} Co_{(1xy)}O_{2})). During charging, lithium ions are extracted from the cathode material and travel through the electrolyte to the anode. This is achieved by applying a voltage to the cell which moves an electron from the cathode to the anode via an external circuit. During discharge, this process is reversed, and the electrons flowing through an outer circuit power th e device of interest, while lithium ions travel from the anode to the cathode through the electrolyte. However, such batteries do not only deliver a current during discharge, but they also inherently generate a voltage difference between anode and cathode. This socalled cell voltage E is determined by the actual materials used in the anode and cathode and depends additionally on the status of charge q ∈ [0,1] of the battery: A fully charged battery (q=1) delivers a higher voltage than a discharged battery (q=0). Additionally, the cell voltage E depends (parametrically) on the C_{h}, where a larger (constant) current yields a steeper voltage decline (see Figure 2). Mathematical models for Lithiumion batteries aim to predict this behavior on the basis of coupled nonequilibrium thermoelectrodynamics.
Mathematical Models
The mathematical modeling of Lithiumion batteries is a multilayered process. As Fig. 1 shows, various length scales arise in modern battery systems, and depending on the actual application of the model, different degrees of resolution are required. Two mainly different approaches arise in this context: Topdown modeling, where the largest scale is described by some heuristic modeling approach, which is refined if some necessity arises, and bottomup approaches, where physically sound models for the smallest scale are stated and systematically upscaled to the desired length scale. At WIAS we rely almost exclusively on bottomup approaches and derive models up to the length scale of full battery cells.
Based on the framework of nonequilibrium thermodynamics, transport equations for the electrolyte phase and the intercalation particles are stated. This yields in general some nonlinear partial differential equations which describe the migration of lithium ions through the electrolyte as well as the diffusion of intercalated lithium in the solid active phases, i.e.?the anode and the cathode. We derive socalled material models in terms of free energy densities, which capture the physicochemical nature of the material, for instance, the abovementioned aspect that intercalation materials can host lithium on interstitial sites in their crystal lattice. These material models are then validated on experimental data, for example on the opencircuit voltage (OCP) of a specific battery material.
The transport equations of the intercalation electrodes and the electrolyte phases are coupled through electrochemical reactions for the Lithium insertion, i.e. the reaction Li^{+} + e^{} ⇌ Li. The modeling of this reaction is based on nonequilibrium surface thermodynamics and yields essentially boundary conditions for the transport equations of the two adjacent phases.
Several other modeling aspects are further considered and continuously developed in the field of battery modeling at WIAS, for instance, mechanical effects upon intercalation, side reactions such as the solidelectrolyteinterphase, metal deposition or gas evaporation, phase transitions within the electrode materials as well as new battery types such as Lithiumsulfur or sodiumion based batteries.
Mathematical Methods
Once all the transport equations and boundary conditions are stated on the scale of the porous electrode, as well as its geometry, mathematical techniques are used to bridge the scale to the electrochemical unit cell. A very important technique is homogenization via multiscale expansions, which allows us, under the assumption of some geometric periodicity of the porous medium, to deduce a coupled, nonlinear partial differential equation system on the next length scale. The great benefit of this method is, that the geometry of the porous electrodes arises only as effective parameters in the transport equations in the electrochemical unit cell. These effective parameters can be computed numerically for a given periodic structure, for instance, the geometry of Fig. 4.
Despite homogenization methods, many other mathematical methods, such as Asymptotic expansions, GradientFlow and Entropymethods as well as the functional analysis to prove the existence and uniqueness of the resulting equation system are employed in the field of battery modeling at WIAS and are continuously further developed by various research groups in the institute.
Numerical Simulations
One the spatial cell of the electrochemical unit cell, one obtains in the simplest case a mathematical model for four variables: (i) the concentration y_{E}(x,t) of lithium ions in the electrolyte, the electrostatic potential (ii) in the electrolyte φ_{E}(x,t) and (iii) φ_{S}(x,t) in the solid electrode, and (iv) the concentration of intercalated lithium y__{A}(x,r,t). While (y_{E},φ_{E}) and (φ_{S}) depend only on the macroscale x, that is the position within the homogenized porous electrode pointing from anode to cathode, the concentration of lithium (y_{A}) in the active particle remains dependent on x and r, where r is the radial position within each particle. This is a consequence of the rather small solidstate diffusivity of lithium in the lattice host material. Figure 5 shows the numerically computed profiles of these variables at some timet.
An important application of such a mathematical model is that it can predict how the cell voltage E changes as a function of the status of chargeq, i.e. the total amount of intercalated lithium in the anode, and simultaneously with respect to the discharge current C_{h}. This is of special importance because in experimental conditions this requires a rather large amount of cells to be discharged.
Several further numerical techniques, such as FiniteElement and FiniteVolumeMethods, contribute to the simulation of Lithiumion batteries at WIAS and are continuously further developed by various research groups in the institute.
Publications
Articles in Refereed Journals

R. Müller, M. Landstorfer, Galilean bulksurface electrothermodynamics and applications to electrochemistry, Entropy. An International and Interdisciplinary Journal of Entropy and Information Studies, 25 (2023), pp. 416/1416/27, DOI 10.3390/e25030416 .
Abstract
In this work, the balance equations of nonequilibrium thermodynamics are coupled to Galilean limit systems of the Maxwell equations, i.e. either to (i) the quasielectrostatic limit or (ii) the quasimagnetostatic limit. We explicitly consider a volume $Omega$ which is divided into $Omega^+$ and $Omega^$ by a possibly moving singular surface S, where a charged reacting mixture of a viscous medium can be present on each geometrical entity ($Omega$^+, S, $Omega^$). By the restriction to Galilean limits of the Maxwell equations, we achieve that only subsystems of equations for matter and electric field are coupled that share identical transformation properties with respect to observer transformations. Moreover, the application of an entropy principle becomes more straightforward and finally it helps to estimate the limitations of the more general approach based the full set of Maxwell equations. Constitutive relations are provided based on an entropy principle and particular care is taken for the analysis of the stress tensor and the momentum balance in the general case of nonconstant scalar susceptibility. Finally, we summarize the application of the derived model framework to an electrochemical system with surface reactions 
M. Landstorfer, R. Müller, Thermodynamic models for a concentration and electric field dependent susceptibility in liquid electrolytes, Electrochimica Acta, 428 (2022), pp. 140368/1140368/19, DOI 10.1016/j.electacta.2022.140368 .
Abstract
The dielectric susceptibility $chi$ is an elementary quantity of the electrochemical double layer and the associated Poisson equation. While most often $chi$ is treated as a material constant, its dependency on the salt concentration in liquid electrolytes is demonstrated by various bulk electrolyte experiments. This is usually referred to as dielectric decrement. Further, it is theoretically well accepted that the susceptibility declines for large electric fields. This effect is frequently termed dielectric saturation. We analyze the impact of a variable susceptibility in terms of species concentrations and electric fields based on nonequilibrium thermodynamics. This reveals some nonobvious generalizations compared to the case of a constant susceptibility. In particular the consistent coupling of the Poisson equation, the momentum balance and the chemical potentials functions are of ultimate importance. In a numerical study, we systematically analyze the effects of a concentration and field dependent susceptibility on the double layer of a planar electrode electrolyte interface. We compute the differential capacitance and the spatial structure of the electric potential, solvent concentration and ionic distribution for various nonconstant models of $chi$. 
M. Landstorfer, M. Ohlberger, S. Rave, M. Tacke, A modelling framework for efficient reduced order simulations of parametrised lithiumion battery cells, European Journal of Applied Mathematics, 34 (2023), pp. 554591 (published online on 29.11.2022), DOI 10.1017/S0956792522000353 .
Abstract
In this contribution we present a new modeling and simulation framework for parametrized Lithiumion battery cells. We first derive a new continuum model for a rather general intercalation battery cell on the basis of nonequilibrium thermodynamics. In order to efficiently evaluate the resulting parameterized nonlinear system of partial differential equations the reduced basis method is employed. The reduced basis method is a model order reduction technique on the basis of an incremental hierarchical approximate proper orthogonal decomposition approach and empirical operator interpolation. The modeling framework is particularly well suited to investigate and quantify degradation effects of battery cells. Several numerical experiments are given to demonstrate the scope and efficiency of the modeling framework. 
M. Landstorfer, B. Prifling, V. Schmidt, Mesh generation for periodic 3D microstructure models and computation of effective properties, Journal of Computational Physics, 431 (2021), pp. 110071/1110071/20 (published online on 23.12.2020), DOI https://doi.org/10.1016/j.jcp.2020.110071 .
Abstract
Understanding and optimizing effective properties of porous functional materials, such as permeability or conductivity, is one of the main goals of materials science research with numerous applications. For this purpose, understanding the underlying 3D microstructure is crucial since it is well known that the materials? morphology has an significant impact on their effective properties. Because tomographic imaging is expensive in time and costs, stochastic microstructure modeling is a valuable tool for virtual materials testing, where a large number of realistic 3D microstructures can be generated and used as geometry input for spatiallyresolved numerical simulations. Since the vast majority of numerical simulations is based on solving differential equations, it is essential to have fast and robust methods for generating highquality volume meshes for the geometrically complex microstructure domains. The present paper introduces a novel method for generating volumemeshes with periodic boundary conditions based on an analytical representation of the 3D microstructure using spherical harmonics. Due to its generality, the present method is applicable to many scientific areas. In particular, we present some numerical examples with applications to battery research by making use of an already existing stochastic 3D microstructure model that has been calibrated to eight differently compacted cathodes. 
J. Fuhrmann, M. Landstorfer, R. Müller, Modeling polycrystalline electrodeelectrolyte interfaces: The differential capacitance, Journal of The Electrochemical Society, 167 (2020), pp. 106512/1106512/15, DOI 10.1149/19457111/ab9cca .
Abstract
We present and analyze a model for polycrystalline electrode surfaces based on an improved continuum model that takes finite ion size and solvation into account. The numerical simulation of finite size facet patterns allows to study two limiting cases: While for facet size diameter $d^facet to 0$ we get the typical capacitance of a spatially homogeneous but possible amorphous or liquid surface, in the limit $L^Debye << d^facet$ , an ensemble of noninteracting single crystal surfaces is approached. Already for moderate size of the facet diameters, the capacitance is remarkably well approximated by the classical approach of adding the single crystal capacities of the contributing facets weighted by their respective surface fraction. As a consequence, the potential of zero charge is not necessarily attained at a local minimum of capacitance, but might be located at a local capacitance maximum instead. Moreover, the results show that surface roughness can be accurately taken into account by multiplication of the ideally flat polycrystalline surface capacitance with a single factor. In particular, we find that the influence of the actual geometry of the facet pattern in negligible and our theory opens the way to a stochastic description of complex real polycrystal surfaces. 
M. Landstorfer, A discussion of the cell voltage during discharge of an intercalation electrode for various Crates based on nonequilibrium thermodynamics and numerical simulations, Journal of The Electrochemical Society, 167 (2020), pp. 013518/1013518/19 (published online on 19.11.2019), DOI 10.1149/2.0182001JES .

M. Landstorfer, Mathematische Modellierung elektrokatalytischer Zellen, Mitteilungen der Deutschen MathematikerVereinigung, 26 (2019), pp. 161163.

W. Dreyer, P. Friz, P. Gajewski, C. Guhlke, M. Maurelli, Stochastic manyparticle model for LFP electrodes, Continuum Mechanics and Thermodynamics, 30 (2018), pp. 593628, DOI 10.1007/s0016101806297 .
Abstract
In the framework of nonequilibrium thermodynamics we derive a new model for porous electrodes. The model is applied to LiFePO4 (LFP) electrodes consisting of many LFP particles of nanometer size. The phase transition from a lithiumpoor to a lithiumrich phase within LFP electrodes is controlled by surface fluctuations leading to a system of stochastic differential equations. The model is capable to derive an explicit relation between battery voltage and current that is controlled by thermodynamic state variables. This voltagecurrent relation reveals that in thin LFP electrodes lithium intercalation from the particle surfaces into the LFP particles is the principal rate limiting process. There are only two constant kinetic parameters in the model describing the intercalation rate and the fluctuation strength, respectively. The model correctly predicts several features of LFP electrodes, viz. the phase transition, the observed voltage plateaus, hysteresis and the rate limiting capacity. Moreover we study the impact of both the particle size distribution and the active surface area on the voltagecharge characteristics of the electrode. Finally we carefully discuss the phase transition for varying charging/discharging rates. 
M. Landstorfer, On the dissociation degree of ionic solutions considering solvation effects, Electrochemistry Communications, 92 (2018), pp. 5659, DOI 10.1016/j.elecom.2018.05.011 .
Abstract
In this work the impact of solvation effects on the dissociation degree of strong electrolytes and salts is discussed. The investigation is based on a thermodynamic model which is capable to predict qualitatively and quantitatively the double layer capacity of various electrolytes. A remarkable relationship between capacity maxima, partial molar volume of ions in solution, and solvation numbers, provides an experimental access to determine the number of solvent molecules bound to a specific ion in solution. This shows that the Stern layer is actually a saturated solution of 1 mol L1 solvated ions, and we point out some fundamental similarities of this state to a saturated bulk solution. Our finding challenges the assumption of complete dissociation, even for moderate electrolyte concentrations, whereby we introduce an undissociated ionpair in solution. We rederive the equilibrium conditions for a twostep dissociation reaction, including solvation effects, which leads to a new relation to determine the dissociation degree. A comparison to Ostwald's dilution law clearly shows the shortcomings when solvation effects are neglected and we emphasize that complete dissociation is questionable beyond 0.5 mol L1 for aqueous, monovalent electrolytes. 
W. Dreyer, C. Guhlke, R. Müller, A new perspective on the electron transfer: Recovering the ButlerVolmer equation in nonequilibrium thermodynamics, Physical Chemistry Chemical Physics, 18 (2016), pp. 2496624983, DOI 10.1039/C6CP04142F .
Abstract
Understanding and correct mathematical description of electron transfer reaction is a central question in electrochemistry. Typically the electron transfer reactions are described by the ButlerVolmer equation which has its origin in kinetic theories. The ButlerVolmer equation relates interfacial reaction rates to bulk quantities like the electrostatic potential and electrolyte concentrations. Since in the classical form, the validity of the ButlerVolmer equation is limited to some simple electrochemical systems, many attempts have been made to generalize the ButlerVolmer equation. Based on nonequilibrium thermodynamics we have recently derived a reduced model for the electrodeelectrolyte interface. This reduced model includes surface reactions but does not resolve the charge layer at the interface. Instead it is locally electroneutral and consistently incorporates all features of the double layer into a set of interface conditions. In the context of this reduced model we are able to derive a general ButlerVolmer equation. We discuss the application of the new ButlerVolmer equations to different scenarios like electron transfer reactions at metal electrodes, the intercalation process in lithiumironphosphate electrodes and adsorption processes. We illustrate the theory by an example of electroplating. 
W. Dreyer, R. Huth, A. Mielke, J. Rehberg, M. Winkler, Global existence for a nonlocal and nonlinear FokkerPlanck equation, ZAMP Zeitschrift fur Angewandte Mathematik und Physik. ZAMP. Journal of Applied Mathematics and Physics. Journal de Mathematiques et de Physique Appliquees, 66 (2015), pp. 293315.
Abstract
We consider a FokkerPlanck equation on a compact interval where, as a constraint, the first moment is a prescribed function of time. Eliminating the associated Lagrange multiplier one obtains nonlinear and nonlocal terms. After establishing suitable local existence results, we use the relative entropy as an energy functional. However, the timedependent constraint leads to a source term such that a delicate analysis is needed to show that the dissipation terms are strong enough to control the work done by the constraint. We obtain global existence of solutions as long as the prescribed first moment stays in the interior of an interval. If the prescribed moment converges to a constant value inside the interior of the interval, then the solution stabilises to the unique steady state. 
W. Dreyer, C. Guhlke, R. Müller, Overcoming the shortcomings of the NernstPlanck model, Physical Chemistry Chemical Physics, 15 (2013), pp. 70757086, DOI 10.1039/C3CP44390F .
Abstract
This is a study on electrolytes that takes a thermodynamically consistent coupling between mechanics and diffusion into account. It removes some inherent deficiencies of the popular NernstPlanck model. A boundary problem for equilibrium processes is used to illustrate the new features of our model. 
W. Dreyer, C. Guhlke, R. Huth, The behavior of a manyparticle cathode in a lithiumion battery, Physica D. Nonlinear Phenomena, 240 (2011), pp. 10081019.

W. Dreyer, M. Gaberšček, C. Guhlke, R. Huth, J. Jamnik, Phase transition and hysteresis in a rechargeable lithium battery, European Journal of Applied Mathematics, 22 (2011), pp. 267290.

W. Dreyer, C. Guhlke, M. Herrmann, Hysteresis and phase transition in manyparticle storage systems, Continuum Mechanics and Thermodynamics, 23 (2011), pp. 211231.
Abstract
We study the behavior of systems consisting of ensembles of interconnected storage particles. Our examples concern the storage of lithium in manyparticle electrodes of rechargeable lithiumion batteries and the storage of air in a system of interconnected rubber balloons. We are particularly interested in those storage systems whose constituents exhibit nonmonotone material behavior leading to transitions between two coexisting phases and to hysteresis. In the current study we consider the case that the time to approach equilibrium of a single storage particle is much smaller than the time for full charging of the ensemble. In this regime the evolution of the probability to find a particle of the ensemble in a certain state, may be described by a nonlocal conservation law of FokkerPlanck type. Two constant parameter control whether the ensemble transits the 2phase region along a Maxwell line or along a hysteresis path or if the ensemble shows the same nonmonotone behavior as its constituents. 
W. Dreyer, J. Jamnik, C. Guhlke, R. Huth, J. Moškon, M. Gaberšček, The thermodynamic origin of hysteresis in insertion batteries, Nature Materials, 9 (2010), pp. 448453.
Contributions to Collected Editions

M. Landstorfer, M. Heida, Energie effizienter speichern, Spektrum der Wissenschaft, Spektrum der Wissenschaft Verlagsgesellschaft mbH, Heidelberg, 2023, pp. 7279.
Talks, Poster

CH. Bayer, D. Kreher, M. Landstorfer, W. Kenmoe Nzali, Volatile electricity markets and battery storage: A modelbased approach for optimal control, MATH+ Day, HumboldtUniversität zu Berlin, October 20, 2023.

M. Eigel, M. Heida, M. Landstorfer, A. Selahi, Recovery of battery ageing dynamics with multiple timescales, MATH+ Day, HumboldtUniversität zu Berlin, October 20, 2023.

M. Landstorfer, A model framework for Lithiumion intercalation cells, 10th International Congress on Industrial and Applied Mathematics (ICIAM 2023), Minisymposium 01140 ``Modelling and simulation of electrochemomechanical processes in batteries and fuel cells'', August 20  25, 2023, Waseda University, Tokyo, Japan, August 25, 2023.

M. Landstorfer, Modeling and validation of material and transport models for electrolytes, Energetic Methods for MultiComponent Reactive Mixtures Modelling, Stability, and Asymptotic Analysis (EMRM 2023), September 13  15, 2023, WIAS, Berlin, September 15, 2023.

M. Landstorfer, Thermodynamic modeling of the electrodeelectrolyte interface  Doublelayer capacitance, solvation number, validation, Van Marum Colloquia, Leiden University, Institute of Chemistry, Netherlands, November 14, 2023.

M. Landstorfer, Thermodynamic modelling of aqueous and aprotic electrodeelectrolyte interfaces and their and double layer capacitance, BunsenTagung 2023  Physical Chemistry of the Energy Transition, 122nd Annual Conference of the German Bunsen Society for Physical Chemistry, June 5  7, 2023, Berlin, June 7, 2023.

M. Landstorfer, A. Selahi, M. Heida, M. Eigel, Recovery of battery ageing dynamics with multiple timescales, MATH+Day 2022, Technische Universität Berlin, November 18, 2022.

M. Landstorfer, Modeling electrochemical systems with continuum thermodynamics  From fundamental electrochemistry to porous intercalation electrodes (online talk), Stochastic & Multiscale Modeling and Computation Seminar (Online Event), Illinois Institute of Technology, Chicago, USA, October 28, 2021.

M. Landstorfer, Modeling of concentration and electric field dependent susceptibilities in electrolytes (online talk), AA2  Materials, Light, Devices, Freie Universität Berlin, HumboldtUniversität zu Berlin, WIAS Berlin, February 26, 2021.

A. Selahi, M. Landstorfer, The double layer capacity of nonideal electrolyte solutions  A numerical study (online poster), 240th ECS meeting (Online Event), October 10  14, 2021.

M. Landstorfer, M. Eigel, M. Heida, A. Selahi, Recovery of battery ageing dynamics with multiple timescales (online poster), MATH+ Day 2021 (Online Event), Technische Universität Berlin, November 5, 2021.

J. Fuhrmann, C. Guhlke, M. Landstorfer, A. Linke, Ch. Merdon, R. Müller, Quality preserving numerical methods for electroosmotic flow, Einstein Semester on Energybased Mathematical Methods for Reactive Multiphase Flows: Kickoff Conference (Online Event), October 26  30, 2020.

M. Landstorfer, Modelling porous intercalation electrodes with continuum thermodynamics and multiscale asymptotics, Oxford Battery Modelling Symposium, March 18  19, 2019, University of Oxford, Pembroke College, UK, March 18, 2019.

M. Landstorfer, Theory and validation of the electrochemical double layer, PC Seminar, AG Prof. Baltruschat, Universität Bonn, Abt. Elektrochemie, March 8, 2019.

S. Cap, M. Landstorfer, D. Klein, R. Schlägl, N. Nickel, Silicon thin films deposited by low pressure chemical vapor deposition on planer current collectors as model system for lithium ion batteries, Advanced Lithium Batteries for Automobile Applications (ABAA 12), Ulm, October 6  9, 2019.

M. Landstorfer, Continuum thermodynamic modelling of electrolytes, BMBF Kickoff Meeting LuCaMag, Bonn, November 7, 2018.

M. Landstorfer, Homogenization methods for electrochemical systems, Workshop ``Numerical Optimization of the PEM Fuel Cell Bipolar Plate'', Zentrum für Solarenergie und WasserstoffForschung (ZSW), Ulm, March 20, 2018.

M. Landstorfer, Modeling and simulation of porous battery electrodes with multiscale homogenization techniques, 69th Annual Meeting of the International Society of Electrochmistry (ISE), September 2  7, 2018, Bologna, Italy, September 6, 2018.

M. Landstorfer, Modellbasierte Abschätzung der Lebensdauer von gealterten LiBatterien für die 2ndLife Anwendung als stationärer Stromspeicher, BMBFStatusseminar zur Förderrichtlinie Mathematik, November 19  20, 2018, Bonn, November 20, 2018.

M. Landstorfer, Modellierung und Upscaling, WIAS (AG 4), BMBF Workshop zu MaLLi2, November 12  13, 2018, Ellwangen, November 12, 2018.

M. Landstorfer, Modelling and simulation of porous battery electrodes with multiscale homogenisation techniques, 6th European Conference on Computational Mechanics, 7th European Conference on Computational Fluid Dynamics (ECCMECFD 2018), June 11  15, 2018, Glasgow, UK, June 14, 2018.

M. Landstorfer, Modelling and simulation of porous battery electrodes with multiscale homogenisation techniques, Solid State Electrochemistry Symposium, November 12  14, 2018, HelmutSchmidtUniversität, Hamburg, November 13, 2018.

M. Landstorfer, Modelling battery electrodes with homogenization techniques, KickOffMeeting zu BMBFProjekt MALLi^2, Universität Ulm, March 21, 2018.

M. Landstorfer, Thermodynamic modeling of electrolytes and their boundary conditions to electrodes, AMaSiS 2018: Applied Mathematics and Simulation for Semiconductors, October 8  10, 2018, WIAS, Berlin, October 9, 2018.

M. Maurelli , A McKeanVlasov SDE with reflecting boundaries, CASA Colloquium, Eindhoven University of Technology, Department of Mathematics and Computer Science, Netherlands, January 10, 2018.

W. Dreyer, J. Fuhrmann, P. Gajewski, C. Guhlke, M. Landstorfer, M. Maurelli, R. Müller, Stochastic model for LiFePO4electrodes, ModVal14  14th Symposium on Fuel Cell and Battery Modeling and Experimental Validation, Karlsruhe, March 2  3, 2017.

P. Gajewski, M. Maurelli, Stochastic methods for the analysis of lithiumion batteries, Matheon Center Days, April 20  21, 2015, Technische Universität Berlin, April 21, 2015.

C. Guhlke, Hysteresis due to nonmonotone material behaviour inside manyparticle systems, SIAM Conference on Mathematical Aspects of Materials Science (MS10), May 23  26, 2010, Philadelphia, USA, May 23, 2010.

C. Guhlke, Hysteresis due to nonmonotone material behaviour inside manyparticle systems, DPG Spring Meeting 2010, March 21  26, 2010, Regensburg, March 25, 2010.

W. Dreyer, Hysteresis and phase transition in manyparticle storage systems, 13th International Conference on Hyperbolic Problems: Theory, Numerics, Applications (HYP 2010), June 14  19, 2010, Beijing, China, June 17, 2010.

W. Dreyer, On a paradox within the phase field modeling of storage systems and its resolution, 8th AIMS International Conference on Dynamical Systems, Differential Equations and Applications, May 25  28, 2010, Technische Universität Dresden, May 26, 2010.

W. Dreyer, On a paradox within the phase field modeling of storage systems and its resolution, PF09  2nd Symposium on PhaseField Modelling in Materials Science, August 30  September 2, 2009, Universität Aachen, Kerkrade, Netherlands, August 31, 2009.

W. Dreyer, Phase transitions and kinetic relations, Séminaire Fluides Compressibles, Université Pierre et Marie Curie, Laboratoire JacquesLouis Lions, Paris, France, September 30, 2009.

W. Dreyer, Phase transitions during hydrogen storage and in lithiumion batteries, EUROTHERM Seminar no. 84: Thermodynamics of Phase Changes, May 25  27, 2009, Université Catholique de Louvain, Namur, Belgium, May 27, 2009.