Development of Experimental Techniques for Parameterization of Multi-scale Lithium-ion Battery Models (original) (raw)
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The parameterisation of a physico-chemical model constitutes a critical part in model development. Conclusions about the internal state of a battery can only be drawn, if a correct set of material parameters is provided for the material combination under consideration. In this work, parameters to fully parameterise a physico chemical model for a 7.5 Ah cell produced by Kokam are determined and are compared with existing literature values. The paper presents parameter values and procedures to determine the parameters. Cells have been opened under argon atmosphere and the geometrical data have been measured. Hg-porosimetry has been conducted to determine porosity, particle radius as well as tortuosity of the electrodes and the separator. Conductivity and diffusion constants of the electrolyte as well as the electronic conductivity of the active material have been measured detecting the voltage response to a dc current. Finally, electrochemical measurements have been conducted on laboratory-made coin cells, in order to determine open circuit voltage curves, diffusion coefficients and charge transfer kinetics of the electrodes as well as their balancing. In part II of this paper, a physico-chemical model is introduced and a validation of the measured parameter set is given, by comparing model results with experiments.
Parameterisation of a Physico-Chemical Model of a Lithium-Ion Battery Part II: Model Validation
To draw reliable conclusions about the internal state of a lithium-ion battery or about ageing processes using physico-chemical models, the determination of the correct set of input parameters is crucial. In the first part of this publication, the complete set of material parameters for model parameterisation has been determined by experiments for a 7.5 Ah cell produced by Kokam. In this part of the publication, the measured set of parameters is incorporated into a physico-chemical model. Model results are compared to validation test results conducted on laboratory-made coin cells produced with materials obtained from the Kokam cell. The model is also compared to laboratory-made coin half cell experiments where anode or cathode materials obtained from the Kokam cell have been tested against metallic lithium as counter electrode, to prove the behaviour of the single electrodes. Finally, the model is scaled to reproduce the original Kokam cell and model results are validated by comparison with measurement results. The influence of temperature is considered as well. It is discussed, to which extent material parameters obtained by experimental investigation of laboratory coin cells can be transferred to commercial cells of the same material. The validity of physico-chemical models to describe cells is shown.
Parameterization of a Physico-Chemical Model of a Lithium-Ion Battery
Journal of The Electrochemical Society, 2015
To draw reliable conclusions about the internal state of a lithium-ion battery or about ageing processes using physico-chemical models, the determination of the correct set of input parameters is crucial. In the first part of this publication, the complete set of material parameters for model parameterization has been determined by experiments for a 7.5 Ah cell produced by Kokam. In this part of the publication, the measured set of parameters is incorporated into a physico-chemical model. Model results are compared to validation test results conducted on the Kokam cell. The influence of current rate and temperature is considered as well as a comparison with pulse tests is shown. It is discussed to which extent material parameters obtained by experimental investigation of laboratory coin cells can be transferred to commercial cells of the same material. The validity of physico-chemical models to describe cells is shown.
Electrochimica Acta, 2014
An analytical model is proposed to describe the two-dimensional distribution of potential and current in planar electrodes of pouch-type lithium-ion batteries. A concentration-independent polarization expression, obtained experimentally, is used to mimic the electrochemical performance of the battery. By numerically solving the charge balance equation on each electrode in conjugation with the polarization expression, the battery behavior during constant-current discharge processes is simulated. Our numerical simulations show that reaction current between the electrodes remains approximately uniform during most of the discharge process, in particular, when depth-of-discharge varies from 5% to 85%. This observation suggests to simplify the electrochemical behavior of the battery such that the charge balance equation on each electrode can be solved analytically to obtain closed-form solutions for potential and current density distributions. The analytical model shows fair agreement with numerical data at modest computational cost. The model is applicable for both charge and discharge processes, and its application is demonstrated for a prismatic 20 Ah nickel-manganese-cobalt lithium-ion battery during discharge processes. (P. Taheri), mansouri@ualberta.net (A. Mansouri), myazdanp@sfu.ca (M. Yazdanpour), mbahrami@sfu.ca (M. Bahrami).
Frontiers in Energy Research, 2022
Lithium-ion batteries are the thriving energy storage device in multiple fields, including automobiles, smart energy grids, and telecommunication. Due to its high complexity in the electrochemical-electrical-thermal system, there are certain non-linear spatiotemporal scales for measuring the performance of lithium-ion batteries. The fusion of experimental and modeling approaches was used in this study to enhance the performance of lithiumion batteries. This article helps to evaluate the properties of the LiMn 2 O 4 cathode material for Li-ion batteries and also characterize the crystalline nature, morphological structure, and ionic and electronic conductivity of the electrode material using an experimental approach. In addition, a new computational model was designed and formulated to support various other models for computational investigation. This simulation was designed to analyze the one-dimensional structure of coin cell batteries and to evaluate electrochemical and thermal performances. All computational performances have been validated with the help of experimental techniques and also provide multiple benchmarks for future integration of experimental and computational approaches.
Electrochemical Mechanism and Structure Simulation of 2D Lithium-Ion Battery
For decades, lithium batteries have attracted much attention. Highly efficient, safe, and convenient batteries are worthy of being investigated and applied in modern life. However, most of the investigation is on the macroscopic device electrical properties such as current-voltage curves. Investigation on the microscopic electrical properties including potential distribution, electrolyte salt concentration distribution, and lithium ion concentration distribution within the batteries during the discharging is still needed. Here, a detailed study of the key electrical properties distributions inside the lithium battery in the discharging status is given. After comparing three widely used cathode materials (LiCoO 2 , LiMn 2 O 4 , and LiFePO 4), LiFePO 4 is found to show the most stable working performance which is consistent with previous reports. This is probably attributed to its most uniform key electrical properties distributions, its high electric conductivity, and crystal structure. A structure is also proposed which might give a hint to stress and temperature release for a longer and safer application of batteries. This simulation study on the key parameters distribution inside the battery may help to achieve a better understanding and hence control on the lithium battery performance and reliability.
A Distributed Analytical Electro-Thermal Model for Pouch-Type Lithium-Ion Batteries
Journal of the Electrochemical Society, 2014
An analytic multi-physics model for pouch-type lithium-ion (Li-ion) batteries is presented. Both electrical and thermal processes are considered in the model to resolve their interplay on heat generation and battery thermal behavior. Voltage response of a sample Liion battery during galvanostatic discharge processes is measured to obtain a concentration-independent polarization expression. By numerically solving the charge balance equation on positive and negative electrodes in conjugation with the polarization expression, it is shown that the transfer current between the electrodes remains approximately constant, in particular when depth-of-discharge is less than 90%. Based on this observation, the electrochemical performance of the battery is simplified, and by using the method of separation of variables a closed-form electrical model is proposed. Joule heating on each electrode, calculated from the electrical model, is used as a local heat source in a two-dimensional battery thermal model. The distributed thermal model is solved analytically with the method of integral transform. The analytical results are successfully validated through comparisons with experimental and numerical data. It is confirmed that ohmic heating in the electrodes contributes to a relatively small portion (8-18%) of the total heat generation; nonetheless, since this heat is highly localized it results in spatial non-uniformity in temperature.
Bridging physics-based and equivalent circuit models for lithium-ion batteries
Electrochimica Acta, 2021
In this article, a novel implementation of a widely used pseudo-two-dimensional (P2D) model for lithium-ion battery simulation is presented with a transmission line circuit structure. This implementation represents an interplay between physical and equivalent circuit models. The discharge processes of an NMC-graphite lithium-ion battery under different currents are simulated, and it is seen the results from the circuit model agree well with the results obtained from a physical simulation carried out in COMSOL Multiphysics, including both terminal voltage and concentration distributions. Finally we demonstrated how the circuit model can contribute to the understanding of the cell electrochemistry, exemplified by an analysis of the overpotential contributions by various processes.
Multiscale modeling and characterization for performance and safety of lithium-ion batteries
Journal of Applied Physics, 2015
Lithium-ion batteries are highly complex electrochemical systems whose performance and safety are governed by coupled nonlinear electrochemical-electrical-thermal-mechanical processes over a range of spatiotemporal scales. Gaining an understanding of the role of these processes as well as development of predictive capabilities for design of better performing batteries requires synergy between theory, modeling, and simulation, and fundamental experimental work to support the models. This paper presents the overview of the work performed by the authors aligned with both experimental and computational efforts. In this paper, we describe a new, open source computational environment for battery simulations with an initial focus on lithium-ion systems but designed to support a variety of model types and formulations. This system has been used to create a three-dimensional cell and battery pack models that explicitly simulate all the battery components (current collectors, electrodes, and ...
Two-Dimensional Lithium-Ion Battery Modeling with Electrolyte and Cathode Extensions
Advances in Chemical Engineering and Science, 2012
A two-dimensional model for transport and the coupled electric field is applied to simulate a charging lithium-ion cell and investigate the effects of lithium concentration gradients within electrodes on cell performance. The lithium concentration gradients within electrodes are affected by the cell geometry. Two different geometries are investigated: extending the length of the electrolyte past the edges of the electrodes and extending the length of the cathode past the edge of the anode. It is found that the electrolyte extension has little impact on the behavior of the electrodes, although it does increase the effective conductivity of the electrolyte in the edge region. However, the extension of the cathode past the edge of the anode, and the possibility for electrochemical reactions on the flooded electrode edges, are both found to impact the concentration gradients of lithium in electrodes and the current distribution within the electrolyte during charging. It is found that concentration gradients of lithium within electrodes may have stronger impacts on electrolytic current distributions, depending on the level of completeness of cell charge. This is because very different gradients of electric potential are expected from similar electrode gradients of lithium concentrations at different levels of cell charge, especially for the Li x C 6 cathode investigated in this study. This leads to the prediction of significant electric potential gradients along the electrolyte length during early cell charging, and a reduced risk of lithium deposition on the cathode edge during later cell charging, as seen experimentally by others.