| 1. |
- Alipour, Mohammad, et al.
(författare)
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A surrogate-assisted uncertainty quantification and sensitivity analysis on a coupled electrochemical–thermal battery aging model
- 2023
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Ingår i: Journal of Power Sources. - : Elsevier BV. - 0378-7753 .- 1873-2755. ; 579
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Tidskriftsartikel (refereegranskat)abstract
- High-fidelity physics-based models are required to comprehend battery behavior at various operating conditions. This paper proposes an uncertainty quantification analysis on a coupled electrochemical–thermal aging model to improve the reliability of a battery model, while also investigating the impact of parametric model uncertainties on battery voltage, temperature, and aging. The coupled model's high computing cost, however, is a significant barrier to perform uncertainty quantification (UQ) and sensitivity analysis (SA). To address this problem, a surrogate model – i.e, by simulating the outcome of a quantity of interest that cannot be easily computed or measured – based on the Gaussian process regression (GPR) theory and principle component analysis (PCA) is built, using a small collection of finite element simulation results as synthetic training data. In total, 43 variable electrochemical–thermal parameters as well as 13 variable aging parameters are studied and estimated. Moreover, the trained surrogate model is also used in the parameterization of the electrochemical and thermal models. The results show that the uncertainties in the input parameters significantly affect the estimations of battery voltage, temperature, and aging. Based on this sensitivity analysis, the most influential parameters affecting the above mentioned battery outputs are reported. This approach is thereby helpful for developing robust and reliable high-fidelity battery aging models with potential applications in digital twins as well as for synthetic data generation.
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| 2. |
- Wang, Yongchao, et al.
(författare)
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Numerical Simulation of Micro-Galvanic Corrosion in Al Alloys : Steric Hindrance Effect of Corrosion Product
- 2018
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Ingår i: Journal of the Electrochemical Society. - : The Electrochemical Society. - 0013-4651 .- 1945-7111. ; 164:14, s. C1035-C1043
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Tidskriftsartikel (refereegranskat)abstract
- An improved finite element model was established to demonstrate the steric hindrance effect of the precipitated corrosion product (Al(OH)(3)) on micro-galvanic corrosion triggered by intermetallic particles (IMPs) in an Al-matrix. In this model, the precipitation/ dissolution of the corrosion product could occur in the whole liquid field as the result of a reversible reaction. Simulation results show that the precipitated insulating Al(OH)(3) on the electrode surface can inhibit further corrosion by reducing the conductivity of the solution and the active electrode surface area. Meanwhile, the steric hindrance effect of the precipitated Al(OH)(3) also slows down the diffusion and migration of species in the solution. Moreover, considering the porous nature of precipitated Al(OH)(3), a porosity parameter epsilon was introduced to describe the degree of compactness of corrosion product, which reaches a certain minimum value epsilon(c) under a specific corrosion situation. Compared to the previous work in which a surface coverage parameter was used to describe the blocking effect of Al(OH)(3) on surface activity, the present model is more realistic in mimicking the micro-galvanic corrosion, and also useful for the simulation of the transition from metastable pit formation to pit propagation.
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| 3. |
- Yin, Litao, et al.
(författare)
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A FEM model for investigation of micro-galvanic corrosion of Al alloys and effects of deposition of corrosion products
- 2016
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Ingår i: Electrochimica Acta. - : Elsevier. - 0013-4686 .- 1873-3859. ; 192, s. 310-318
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Tidskriftsartikel (refereegranskat)abstract
- A finite element method model has been elaborated aiming at a deeper insight into the influence of microstructure on micro-galvanic corrosion of Al alloys. The model considers a dynamic corroding surface and takes into account kinetic data from local electrochemical reactions, transport of O-2 and ionic species (e.g., Al3+, H+, Cl-), homogeneous reactions in the electrolyte, deposition of reaction products and its influence on both anodic and cathodic reactions. As a first step, an Al matrix with a micrometer-sized cathodic intermetallic particle exposed in 0.1 M NaCl has been considered. The simulation predicts the dynamic changes of the corroding surface, and the flow and distribution of ionic species and of O-2 in space and time. The calculated pH of the electrolyte inside and nearby the occluded corroding volume suggests the formation of insoluble Al(OH)(3) on both the cathodic and anodic areas. This results in blocking effects of anodic and cathodic reactions and in eventual termination of the micro-galvanic corrosion. The predicted deposition of corrosion product is in good agreement with in-situ atomic force microscopy measurements.
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| 4. |
- Yin, Litao, et al.
(författare)
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An Integrated Flow–Electric–Thermal Model for a Cylindrical Li-Ion Battery Module with a Direct Liquid Cooling Strategy
- 2022
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Ingår i: Energy Technology. - : Wiley. - 2194-4296 .- 2194-4288. ; 10:8
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Tidskriftsartikel (refereegranskat)abstract
- An integrated model is constructed for a Li-ion battery module composed of cylindrical cells by coupling individual first-order equivalent circuit models (ECMs) with a 3D heat transfer model, also considering the fluid flow dynamics of the applied cooling liquid, and bench-marked against experimental data. This model simulates a representative unit of the battery module with direct liquid cooling in a parallel configuration. Instead of assigning specific values to the featured parameters involved in the ECMs, they are here defined as 4D arrays. This makes it possible to simultaneously consider the effect of the state of charge, current rate, and temperature on the battery dynamics, making the model more adaptive, versatile, and connectable to the battery cell electrochemistry. According to the simulation results, the model employing state-dependent battery properties fits better with the experimental cooling results. Additionally, the temperature uniformity of the module with a parallel cooling configuration is improved compared to a serial configuration. However, the increase of the absolute core temperature cannot be directly controlled by the surface cooling due to the slow heat transport rate across the battery material. The simulations also provide directions for the modification of module design, to the potential benefit of battery pack developers.
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| 5. |
- Yin, Litao, et al.
(författare)
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Analyzing and mitigating battery ageing by self-heating through a coupled thermal-electrochemical model of cylindrical Li-ion cells
- 2021
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Ingår i: Journal of Energy Storage. - : Elsevier BV. - 2352-152X .- 2352-1538. ; 39
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Tidskriftsartikel (refereegranskat)abstract
- An integrated battery model is constructed by coupling a three-dimensional electrochemical model with a two-dimensional axisymmetric heat transfer model, and implemented for simulation of the thermal behavior in a 21,700-type cylindrical cell, comprising a graphite/LiNi0.8Co0.15Al0.05O2 chemistry. The electrochemical model is based on the disassembled battery structure and considers the temperature-dependent ageing kinetics induced by solid electrolyte interphase (SEI) formation and metallic Li plating. Compared with a classic pseudo-2D (P2D) model, the proposed model provides better fitting results for both battery electrochemical and thermal properties. The simulation results show battery surface temperatures can reach up to 80 °C and 110 °C for discharge rates of 3C and 4C, respectively. By applying appropriate cooling liquids, this surface temperature increase can be efficiently controlled and the core temperature will be correspondingly reduced, while the internal temperature gradient remains the same. It is primarily the improvement of thermal conductivity in radial direction which can reduce differences between core and surface temperature. Moreover, the model is able to characterize accelerated ageing kinetics caused by battery self-heating during operation. The results show that the capacity of the investigated battery decreases to 80% after 500 cycles, which is in good agreement with commercial specifications.
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| 6. |
- Yin, Litao, et al.
(författare)
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Experimental and Simulation Investigations of Copper Reduction Mechanism with and without Addition of SPS
- 2018
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Ingår i: Journal of the Electrochemical Society. - : ELECTROCHEMICAL SOC INC. - 0013-4651 .- 1945-7111. ; 165:13, s. D604-D611
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Tidskriftsartikel (refereegranskat)abstract
- Rotating disk electrode and rotating ring-disk electrode were used to investigate the mechanism of copper reduction and the influence of convection on the effect of Bis-3-sodiumsulfopropyl disulfide (SPS), a widely used accelerator in copper via-filling and copper foil manufacturing. The experimental results show that the commonly accepted single electron transfer for copper reduction is dominating in the low overpotential range, whereas the double electron transfer is also involved in the high overpotential range. SPS was found to exhibit a weak inhibition effect even with Cl- ion in the solution under strong convection, and generate more intermediates in the solution with both Cl- ion and SPS than with Cl- ion alone. Based on the experimental observations, a reaction model for copper reduction considering competition between the single electron transfer and the double electron transfer, as well as desorption and runoff of generated Cu+-containing intermediates, was proposed and used for finite element method modeling. The simulation results enable quantitative description of the proportion of the two charge transfer reactions and the runoff of the intermediates, providing guidelines for selecting the additives and plating conditions in industrial manufacturing.
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| 7. |
- Yin, Litao
(författare)
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FEM Modelling of Micro-galvanic Corrosion in Al Alloys Induced by Intermetallic Particles : Exploration of Chemical and Geometrical Effects
- 2018
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Localized corrosion, such as pitting, crevice corrosion or galvanic corrosion, is a long-standing phenomenon that can greatly limit the life of metallic materials. For decades experimental methods have been used to try to understand the underlying physical, chemical and electrochemical processes that control localized corrosion in order to find effective protection methods against its propagation. The complexity of the phenomenon and its small geometric size have often severely restricted the basic understanding of local corrosion. In recent decades, computational methods have been developed as an alternative to the experimental methods. Compared to experimental methods, modeling and numerical simulation enable complicated systems to be systematically investigated without considering the inherent constraints of experimental methods. In the current Doctoral thesis, advanced calculation methodology has been used to study galvanic corrosion of an aluminum alloy with geometric resolution at micrometer level. The computational platform has been a commercial FEM-based software, COMSOL Multiphysics, which was combined with another software, Matlab. The current model system consists of a semi-spherical intermetallic particle, surrounded by a pure aluminum matrix. The aluminum surface is covered by an inert passive film, except for a ring-shaped surface around the particle itself. By assuming that the particle is electrochemically more noble than aluminum, it acts as a cathode and the surrounding aluminum ring as anode. By utilizing the FEM-based software, it has been possible to incorporate important physicochemical reactions, including the electrochemical anode and cathode reactions of the individual phases, mass transport of various chemical compounds formed during ongoing electrochemistry, homogeneous reactions in the electrolyte, as well as deposition of corrosion products consisting of Al(OH)3 along parts of the anodic area. What has made this study a significant step forward is that not only chemical changes but also geometrical changes have been taken into consideration in the simulation of ongoing micro-galvanic corrosion. Particularly challenging has been to mathematically master the gradual deposition of compact Al(OH)3 on an aluminum surface which gradually dissolves anodically. In the initial modeling work, the deposition of Al(OH)3 was assumed to occur only on the electrode surface, resulting in a gradual blockage of surface activity. In an even more advanced stage, the modeling has also sought to simulate the effect of a deposited porous film of Al(OH)3, formed through homogeneous reactions in the electrolyte. By taking into account inhibited diffusion and migration of chemical products that the porous film causes, its sterically inhibiting effect has for the first time been quantitatively interpreted. The porous corrosion product can most closely resemble the lid experimentally observed above local corrosion attacks, which leads to an even more diminished surface activity in electrochemical reactions compared with the deposition of only compact corrosion products on the anode surface. The kinetic model has resulted in a significantly deeper insight into the mechanism of micro-galvanic corrosion of the investigated system. The simulation has been shown to predict the time-dependent geometric changes of the anodically dissolved aluminum surface as well as the flow and distribution of generated chemical products. Contrary to the widely accepted perception that Al(OH)3 is not stable in the occluded acidified electrolyte environment, the calculations predict a higher local pH in the occluded electrolyte. This means that insoluble Al(OH)3 can be deposited on the electrode surface, the blocking effect of which may lead to a termination of the micro-galvanic corrosion. If the ring width is initially 0.5 μm or less, transport of OH- ions from the cathode surface to the occluded electrolyte environment is limited, leading to a local acidification within the occluded dissolving volume. At a given anodic ring width, an increased radius of the cathodic particle instead leads to an increased anodic dissolution rate by formation of a larger area for the cathode reaction. Variation of the chemical parameters in the electrolyte also shows that the simulated micro-galvanic corrosion rate of aluminum has a minimum at pH = 6. Both more acidic and more alkaline conditions result in an elevated anodic dissolution of aluminum. When pH ≤ 4, the deposition of Al(OH)3 becomes negligible, and the micro-galvanic corrosion will continue uninterrupted, completely in accordance with experimental data.
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| 8. |
- Yin, Litao, et al.
(författare)
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Implementing intermittent current interruption into Li-ion cell modelling for improved battery diagnostics
- 2022
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Ingår i: Electrochimica Acta. - : Elsevier BV. - 0013-4686 .- 1873-3859. ; 427
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Tidskriftsartikel (refereegranskat)abstract
- A novel electroanalytical method, the intermittent current interruption (ICI) technique, has recently been promoted as a versatile tool for battery analysis and diagnostics. The technique enables frequent and continuous measurement of battery resistance, which then undergoes statistical analysis. Here, this method is implemented for commercial Li-ion cylindrical cells, and combined with a physics-based finite element model (FEM) of the battery to better interpret the measured resistances. Ageing phenomena such as solid electrolyte interphase (SEI) formation and metallic Li plating on the surface of the negative graphite particles are considered in the model. After validation, a long-term cycling simulation is conducted to mimic the ageing scenario of commercial cylindrical 21700 cells. The large number of internal resistance measurements obtained are subsequently visualized by creating a ‘resistance map’ as a function of both capacity and cycle numbers, providing a straight-forward image of their continuous evolution. By correlating the observed ageing scenarios with specific physical processes, the origins of ageing are investigated. The result shows that a decrease of the electrolyte volume fraction contributes significantly to the increase of internal resistance and affect the electrolyte diffusivity properties. Additionally, effects of porosity and particle radius of the different electrodes are investigated, providing valuable suggestions for battery design.
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| 9. |
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| 10. |
- Yin, Litao, et al.
(författare)
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Numerical Simulation of Micro-Galvanic Corrosion in Al Alloys : Effect of Geometric Factors
- 2017
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Ingår i: Journal of the Electrochemical Society. - : ELECTROCHEMICAL SOC INC. - 0013-4651 .- 1945-7111. ; 164:2, s. C75-C84
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Tidskriftsartikel (refereegranskat)abstract
- A finite element model for simulating the propagation of intermetallic particle driven micro-galvanic corrosion in an Al-matrix model system is presented. The model revealed dynamic changes related to localized corrosion, including the moving dissolution boundary, the deposition of reaction products (Al(OH)(3)), and their blocking effect. Modelling was focused on the effects of key geometric parameters, including the radius of cathodic particle (range 0.5 to 4 mu m) and the width of an assumed anodic ring surrounding the particle (range 0.1 to 2 mu m). Simulations revealed the dynamic flow of molecular and ionic species, along with influence of geometrical constraints. For ring widths below 0.5 mu m, deposition of Al(OH)(3) inside the dissolving volume was inhibited due to limited transport of OH- and O-2 into a constrained volume - resulting in local acidification. An increase in cathodic particle radius at given ring width resulted in a greater dissolution by providing a larger cathodic area for O-2 reduction, quantifying the effect of cathode/anode ratio. The model was also developed to include two cathodic particles to explore any interaction. The present study reveals a physicochemical model that contributes toward a framework for multi-process localized corrosion systems, which can be further adapted to commercial alloy systems.
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| 11. |
- Yin, Litao, et al.
(författare)
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Numerical Simulation of Micro-Galvanic Corrosion of Al Alloys : Effect of Chemical Factors
- 2017
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Ingår i: Journal of the Electrochemical Society. - : Electrochemical Society Inc. - 0013-4651 .- 1945-7111. ; 164:13, s. C768-C778
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Tidskriftsartikel (refereegranskat)abstract
- A finite element model for simulating the propagation of micro-galvanic corrosion of Al alloys induced by intermetallic particle was established to reveal the dynamic changes including a moving dissolution boundary, deposition of reaction products and their blocking effect. This model has previously been used to study the influence of geometrical factors such as the particle size and width of the anodic ring. In this work, we explore effects of chemical factors including pH and bulk concentration of O-2 by using chemical-dependent electrochemical kinetics as input parameters. The simulations reveal that the micro-galvanic corrosion rate is slowest at pH = 6. For pH > 6, the rise of pH increases the dissolution rate of Al and also the deposition rate of Al(OH)(3), leading to a faster but more short localized Al dissolution. For pH < 6, the decline of pH accelerates Al dissolution and inhibits Al(OH)(3) deposition, leading to a faster and more long lasting Al dissolution. At pH <= 4, deposition of Al(OH)(3) becomes negligible, and localized corrosion will propagate continuously. Within the O-2 concentration range relevant for atmospheric conditions, a lower O-2 concentration in the solution leads to a slower rate of micro-galvanic corrosion.
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| 12. |
- Yin, Litao, et al.
(författare)
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Numerical simulation of micro-galvanic corrosion of Al alloys : Effect of density of Al(OH)(3) precipitate
- 2019
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Ingår i: Electrochimica Acta. - : PERGAMON-ELSEVIER SCIENCE LTD. - 0013-4686 .- 1873-3859. ; 324
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Tidskriftsartikel (refereegranskat)abstract
- This work is a further step to develop a finite element model to simulate localized corrosion of aluminum alloys driven by micro-galvanic effects. The focus herein is to explore the effect of density (porosity and tortuosity) of Al(OH)(3) precipitates generated both on the electrode surface and in the liquid phase. Two coupled processes are identified and discussed, both influencing the local pH: the Al3+ dissolution from the electrode surface, and the steric hindrance effects on mass transport of species between the bulk solution and the anolyte next to the corroding surface. With the densest precipitate investigated, Al3+ dissolution is more effectively blocked and the mass transport largely hindered of Al3+ ions leaving the electrode surface. With increasing porosity of the precipitate, Al3+ dissolution is enhanced, also the mass transport of species in the electrolyte. The most severe localized acidification inside the occluded volume occurs when the density, namely ascribed by porosity, of precipitate is at an intermediate level with epsilon(c )= 0.01. In qualitative agreement with experimental observations, this work highlights the importance of corrosion product density on the progress of localized corrosion.
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