Reduced Order Modeling of Mechanical Degradation Induced Performance Decay in Lithium-Ion Battery Porous Electrodes PDF Download
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Languages : en
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In this paper, a one-dimensional computational framework is developed that can solve for the evolution of voltage and current in a lithium-ion battery electrode under different operating conditions. A reduced order model is specifically constructed to predict the growth of mechanical degradation within the active particles of the carbon anode as a function of particle size and C-rate. Using an effective diffusivity relation, the impact of microcracks on the diffusivity of the active particles has been captured. Reduction in capacity due to formation of microcracks within the negative electrode under different operating conditions (constant current discharge and constant current constant voltage charge) has been investigated. At the beginning of constant current discharge, mechanical damage to electrode particles predominantly occurs near the separator. As the reaction front shifts, mechanical damage spreads across the thickness of the negative electrode and becomes relatively uniform under multiple discharge/charge cycles. Mechanical degradation under different drive cycle conditions has been explored. It is observed that electrodes with larger particle sizes are prone to capacity fade due to microcrack formation. Finally, under drive cycle conditions, small particles close to the separator and large particles close to the current collector can help in reducing the capacity fade due to mechanical degradation.
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Languages : en
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Book Description
In this paper, a one-dimensional computational framework is developed that can solve for the evolution of voltage and current in a lithium-ion battery electrode under different operating conditions. A reduced order model is specifically constructed to predict the growth of mechanical degradation within the active particles of the carbon anode as a function of particle size and C-rate. Using an effective diffusivity relation, the impact of microcracks on the diffusivity of the active particles has been captured. Reduction in capacity due to formation of microcracks within the negative electrode under different operating conditions (constant current discharge and constant current constant voltage charge) has been investigated. At the beginning of constant current discharge, mechanical damage to electrode particles predominantly occurs near the separator. As the reaction front shifts, mechanical damage spreads across the thickness of the negative electrode and becomes relatively uniform under multiple discharge/charge cycles. Mechanical degradation under different drive cycle conditions has been explored. It is observed that electrodes with larger particle sizes are prone to capacity fade due to microcrack formation. Finally, under drive cycle conditions, small particles close to the separator and large particles close to the current collector can help in reducing the capacity fade due to mechanical degradation.
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Languages : en
Pages : 19
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Mechanical degradation, owing to intercalation induced stress and microcrack formation, is a key contributor to the electrode performance decay in lithium-ion batteries (LIBs). The stress generation and formation of microcracks are caused by the solid state diffusion of lithium in the active particles. Here in this work, scaling relations are constructed for diffusion induced damage in intercalation electrodes based on an extensive set of numerical experiments with a particle-level description of microcrack formation under disparate operating and cycling conditions, such as temperature, particle size, C-rate, and drive cycle. The microcrack formation and evolution in active particles is simulated based on a stochastic methodology. A reduced order scaling law is constructed based on an extensive set of data from the numerical experiments. The scaling relations include combinatorial constructs of concentration gradient, cumulative strain energy, and microcrack formation. Lastly, the reduced order relations are further employed to study the influence of mechanical degradation on cell performance and validated against the high order model for the case of damage evolution during variable current vehicle drive cycle profiles.
Author: Mohammed Fouad Hasan
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Languages : en
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Li-ion batteries, owing to their unique characteristics with high power and energy density, are broadly considered a leading candidate for vehicle electrification. A pivotal performance drawback of the Li-ion batteries manifests in the lengthy charging time and the limited cycle life. Fast charging is one of the most desired characteristics for the emerging vehicle technologies, which is at a nascent stage and not well understood. Moreover, cycle life is a vital component of battery integration and market penetration. The objectives of this work include: (1) investigating the fast charging induced performance limitations with emphasis on temperature extremes; and (2) studying the implications of combined chemical and mechanical degradation modes on the battery cycle life. In this work, a coupled electrochemical-thermal model is utilized to study the internal behavior and thermal interactions during fast charging process. Additionally, the cycle life predictions are realized by developing a capacity fade model consisting of a coupled chemical (irreversible solid electrolyte interface formation) and mechanical (intercalation induced damage) degradation formalism with thermal effect. Primary results with conventional protocol at high rate (3C) show that at moderate and high operating temperatures the main performance limitations of fast charging originate from lithium ion transport in the electrolyte and ohmic resistance. However, charge transfer resistance is found to be the limiting mechanism for the conventional 1C charging rate at low temperatures. Furthermore, it was found that the concentration build-up at anode surface can be effectively manipulated by using an appropriate charging protocol such as pulse charging and boostcharging. However, it was concluded that at low temperatures, a successful charging protocol is achieved by utilizing the principle of thermal excitement. For battery cycle life, results show that mechanical degradation is the predominant mechanism for capacity fade at low temperatures and high rates. However, the temperature as a stress factor is the principle capacity fade source at high operating temperatures where mechanical degradation is not prominent. The importance of cooling condition, particle size and the exchange current density on life cycle have been emphasized. Finally, a degradation phase map that shows the significance of active particle size and stress factors (temperature and current rate) on the capacity fade is presented. It is concluded that the particle size showed a trade-off in the capacity fade results at different temperatures. The electronic version of this dissertation is accessible from http://hdl.handle.net/1969.1/152626
Author: John Newman
Publisher: John Wiley & Sons
ISBN: 0471478423
Category : Science
Languages : en
Pages : 671
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Book Description
The new edition of the cornerstone text on electrochemistry Spans all the areas of electrochemistry, from the basicsof thermodynamics and electrode kinetics to transport phenomena inelectrolytes, metals, and semiconductors. Newly updated andexpanded, the Third Edition covers important new treatments, ideas,and technologies while also increasing the book's accessibility forreaders in related fields. Rigorous and complete presentation of the fundamentalconcepts In-depth examples applying the concepts to real-life designproblems Homework problems ranging from the reinforcing to the highlythought-provoking Extensive bibliography giving both the historical developmentof the field and references for the practicing electrochemist.
Author: Supratim Das
Publisher:
ISBN:
Category :
Languages : en
Pages : 0
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Book Description
Lithium-ion batteries have become the centerpiece of portable technology and electric transportation, as well as for grid stabilization for intermittent renewable sources. The varied applications involve varying requirements for safety, lifetime, and energy/power density. To optimally design these systems for each application, researchers have a very large design space. This requires extensive and costly experimentation or computationally heavy modeling. Specifically for designing batteries with better lifetime and long-term capacity retention, relying on just experiments can take between weeks to months and thousands of cells to get any robust insights for process improvement. Data-driven and physics based modeling, when done rigorously, can help inform experimentation, reducing time and cost requirements. However, modeling battery degradation is challenging as it not only is hard to visualize in-operando, but also affects cell performance at multiple scales - from single particle to porous electrode to the battery pack. Insights obtained from experimentation on a given scale to inform modeling, often performs poorly when it comes to prediction at other scales, limiting applicability. This thesis is a small part of a collaboration between MIT, Stanford, Purdue and Toyota Research Institute to develop data-driven models for predicting battery performance and degradation, called the D3BATT: Data-Driven Design of Lithium-ion Batteries. We adopt a simultaneous 'bottom-up' (first principles) and 'top-down' (statistical analyses of experiments) approach to inform theory formulation at multiple scales. This thesis addresses the idea behind a multiscale 'bottom-up' approach to understanding battery degradation: First, we use experiments designed on simple systems to study the electrochemistry of key graphite degradation mechanisms such as solid-electrolyte interphase (SEI) growth and lithium plating at the single particle scale. This gives us robust kinetic and thermodynamic parameters that are invariant with scale. Second, we extend the single particle theory to the porous electrode scale to capture the effect of multi-particle interactions and macroscopic electrode and electrolyte properties. This is done using the Multiphase Porous Electrode Theory (MPET) software, developed in the Bazant Group at MIT. Third, by simulating various cycling protocols (such as slow and fast charging, full depth-of-discharge vs. shallow formation cycling and open-circuit storage), we can compare the predictions with that of data-driven models obtained from statistical analyses of cell data. This informs the porous electrode model of the key mechanisms relevant at the cell scale, and gives a reliable estimate of electrode-scale parameters that could not have been informed from single-particle models. As an example, we apply the informed porous electrode degradation model to battery formation cycling, and explain what makes a 'good' formation cycling protocol. Model improvement is an ongoing effort in the research group, as new experimental data come to light. This work can be applied to a multitude of cycling scenarios and battery chemistries to assist experimental design.
Author: Sumitava De
Publisher:
ISBN:
Category : Electronic dissertations
Languages : en
Pages : 131
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Electrochemical power sources, especially lithium ion batteries have become major players in various industrial sectors, with applications ranging from low power/energy demands to high power/energy requirements. But there are some significant issues existing for lithium ion systems which include underutilization, stress-induced material damage, capacity fade, and the potential for thermal runaway. Therefore, better design, operation and control of lithium ion batteries are essential to meet the growing demands of energy storage. Physics based modeling and simulation methods provide the best and most accurate approach for addressing such issues for lithium ion battery systems. This work tries to understand and address some of these issues, by development of physics based models and efficient simulation of such models for battery design and real time control purposes. This thesis will introduce a model-based procedure for simultaneous optimization of design parameters for porous electrodes that are commonly used in lithium ion systems. The approach simultaneously optimizes the battery design variables of electrode porosities and thickness for maximization of the energy drawn for an applied current, cut-off voltage, and total time of discharge. The results show reasonable improvement in the specific energy drawn from the lithium ion battery when the design parameters are simultaneously optimized. The second part of this dissertation will develop a 2-dimensional transient numerical model used to simulate the electrochemical lithium insertion in a silicon nanowire (Si NW) electrode. The model geometry is a cylindrical Si NW electrode anchored to a copper current collector (Cu CC) substrate. The model solves for diffusion of lithium in Si NW, stress generation in the Si NW due to chemical and elastic strain, stress generation in the Cu CC due to elastic strain, and volume expansion in the Si NW and Cu CC geometries. The evolution of stress components, i.e., radial, axial and tangential stresses in different regions in the Si NW are studied in details. Lithium-ion batteries are typically modeled using porous electrode theory coupled with various transport and reaction mechanisms with an appropriate discretization or approximation for the solid phase diffusion within the electrode particle. One of the major difficulties in simulating Li-ion battery models is the need for simulating solid-phase diffusion in the second radial dimension r within the particle. It increases the complexity of the model as well as the computation time/cost to a great extent. This is particularly true for the inclusion of pressure induced diffusion inside particles experiencing volume change. Therefore, to address such issues, part of the work will involve development of efficient methods for particle/solid phase reformulation - (1) parabolic profile approach and (2) a mixed order finite difference method. These models will be used for approximating/representing solid-phase concentration variations within the active material. Efficiency in simulation of particle level models can be of great advantage when these are coupled with macro-homogenous cell sandwich level battery models.
Author: Seongkoo Cho
Publisher:
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Category :
Languages : en
Pages :
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A major amount of degradation in battery life is in the form of chemical degradation due to the formation of Solid Electrolyte Interface (SEI) which is a passive film resulting from chemical reaction. Mechanical degradation in the form of fracture formation due to diffusion induced stress can aggravate the aging of the electrode. These mechanisms of deterioration are primary contributors on limiting the durability of Lithium-ion battery (LIB). In addition, an composition of insertion materials such as active material, additive, and binder as well as active particle's morphological heterogeneity can influence solid-state transport, electronic conductivity and hence, battery performance. In this study, virtual 3-D microstructures of LIB electrodes with intercalation particles are designed to describe the influence of microstructure on effective electrical conductivity and the electrochemical impedance. The technique of digital stochastic modeling has been employed for the generation of electrode microstructures consisting of active material, binder, conductive additive and electrolyte. Physicochemical properties for each of the constituent phases have been duly accounted for. Mathematical models have been developed to characterize the electrochemical impedance of LIB electrode. In this work, we demonstrate the coupling of electrode microstructures to the solid state diffusion impedance response in LIB electrodes. This model considers not only the effect of heterogeneity in active particle size on the diffusion impedance response, but also the effect of electrical conductivity, interfacial surface area of the active materials, and volume fraction of the active materials in the porous electrode on the impedance response. In addition, the impact of the morphology of the active materials on the diffusion impedance response through utilization of the characteristic diffusion length of active particles and a Sauter mean particle size has been demonstrated. In order to show the effect of chemical degradation on the impedance response with focus on aging, the Li-ion diffusion inside an active particle is considered along with SEI. Finally, mechanical degradation induced increase in impedance is analyzed by coupling diffusion induced fracture with impedance. These approaches are envisioned to offer a virtual impedance response probing framework to elucidate the influence of electrode microstructural variability and underlying electrochemical and transport interactions. The electronic version of this dissertation is accessible from http://hdl.handle.net/1969.1/151935
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Category :
Languages : en
Pages : 53
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Lithium-ion battery particle-scale (non-porous electrode) simulations applied to resolved electrode geometries predict localized phenomena and can lead to better informed decisions on electrode design and manufacturing. This work develops and implements a fully-coupled finite volume methodology for the simulation of the electrochemical equations in a lithium-ion battery cell. The model implementation is used to investigate 3D battery electrode architectures that offer potential energy density and power density improvements over traditional layer-by-layer particle bed battery geometries. Advancement of micro-scale additive manufacturing techniques has made it possible to fabricate these 3D electrode microarchitectures. A variety of 3D battery electrode geometries are simulated and compared across various battery discharge rates and length scales in order to quantify performance trends and investigate geometrical factors that improve battery performance. The energy density and power density of the 3D battery microstructures are compared in several ways, including a uniform surface area to volume ratio comparison as well as a comparison requiring a minimum manufacturable feature size. Significant performance improvements over traditional particle bed electrode designs are observed, and electrode microarchitectures derived from minimal surfaces are shown to be superior. A reduced-order volume-averaged porous electrode theory formulation for these unique 3D batteries is also developed, allowing simulations on the full-battery scale. Electrode concentration gradients are modeled using the diffusion length method, and results for plate and cylinder electrode geometries are compared to particle-scale simulation results. Additionally, effective diffusion lengths that minimize error with respect to particle-scale results for gyroid and Schwarz P electrode microstructures are determined.
Author: Bradley Louis Trembacki
Publisher:
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Category :
Languages : en
Pages : 278
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Lithium-ion batteries are commonly modeled using a volume-averaged formulation (porous electrode theory) in order to simulate battery behavior on a large scale. These methods utilize effective material properties and assume a simplified spherical geometry of the electrode particles. In contrast, a particle-scale (non-porous electrode) simulation applied to resolved electrode geometries predicts localized phenomena. Complete simulations of batteries require a coupling of the two scales to resolve the relevant physics. A central focus of this thesis is to develop a fully-coupled finite volume methodology for the simulation of the electrochemical equations in a lithium-ion battery cell at both the particle scale and using volume-averaged formulations. Due to highly complex electrode geometries at the particle scale, the formulation employs an unstructured computational mesh and is implemented within the MEMOSA software framework of Purdue’s PRISM (Prediction of Reliability, Integrity and Survivability of Microsystems) center. Stable and efficient algorithms are developed for full coupling of the nonlinear species transport equations, electrostatics, and Butler-Volmer kinetics. The model is applied to synthetic electrode particle beds for comparison with porous electrode theory simulations and to evaluate numerical performance capabilities. The model is also applied to a half-cell mesh created from a real cathode particle bed reconstruction to demonstrate the feasibility of such simulations. The second focus of the thesis is to investigate 3D battery electrode architectures that offer potential energy density and power density improvements over traditional particle bed battery geometries. A singular feature of these geometries is their interpenetrating nature, which significantly reduces diffusion distance. Advancement of micro-scale additive manufacturing techniques has made it possible to fabricate these electrode microarchitectures. A fully-coupled finite volume methodology for the transport equations coupled to the relevant electrochemistry is implemented in the PETSc (Portable, Extensible Toolkit for Scientific Computation) software framework which allows for a straightforward scalable simulation on orthogonal hexahedral meshes. Such scalability becomes important when performing simulations on fully resolved microstructures with many parameter sweeps across multiple variables. Using the computational model, a variety of 3D battery electrode geometries are simulated and compared across various battery discharge rates and length scales in order to quantify performance trends and investigate geometrical factors that improve battery performance. The energy density and power density of the 3D battery microstructures are compared in several ways, including a uniform surface area to volume ratio comparison as well as a comparison requiring a minimum manufacturable feature size. Significant performance improvements over traditional particle bed electrode designs are observed, and electrode microarchitectures derived from minimal surfaces are shown to be superior under a minimum feature size constraint. An average Thiele modulus formulation is presented to predict the performance trends of 3D microbattery electrode geometries. As a natural extension of the 3D battery particle-scale modeling, the third and final focus of the thesis is the development and evaluation of a volume-averaged porous electrode theory formulation for these unique 3D interpenetrating geometries. It is necessary to average all three material domains (anode, cathode, and electrolyte) together, in contrast to traditional two material volume-averaging formulations for particle bed geometries. This model is discretized and implemented in the PETSc software framework in a manner similar to the particle-scale implementation and enables battery-level simulations of interpenetrating 3D battery electrode architectures. Electrode concentration gradients are modeled using a characteristic diffusion length, and results for plate and cylinder electrode geometries are compared to particle-scale simulation results. Additionally, effective diffusion lengths that minimize error with respect to particle-scale results for gyroid and Schwarz P electrode microstructures are determined, since a theoretical single diffusion length is not easily calculated. Using these models, the porous electrode formulation for these 3D interpenetrating geometries is shown to match the results of particle-scale models very well.
Author: Fridolin Röder
Publisher:
ISBN: 9783832549275
Category :
Languages : en
Pages : 0
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This book provides a comprehensive methodology for multiscale simulation of degradation in lithium-ion batteries. The work helps to understand battery degradation processes by revealing complex multiscale effects, which cannot be taken into account by single-scale models. A novel numerical method is presented, which dynamically couples molecular models based on kinetic Monte Carlo method with macroscopic models. Moreover, the work provides mathematical models of degradation on various length scales, e.g. heterogeneous side reactions on molecular scale and the restructuring of particle size distributions on electrode scale. Instead of describing processes separately, the multiscale methodology systematically analyzes interaction of degradation processes and cell operation. The presented methodology is certainly applicable to other electrochemical systems with considerable multi-scale nature.
