• Title/Summary/Keyword: Electrochemical Simulation

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Development and Validation of an Energy Management System for an Electric Vehicle with a split Battery Storage System

  • Becker, Jan;Schaeper, Christoph;Rothgang, Susanne;Sauer, Dirk Uwe
    • Journal of Electrical Engineering and Technology
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    • v.8 no.4
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    • pp.920-929
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    • 2013
  • Within the project 'e performance' supported by the German Ministry of Education and Research (BMBF) an electric vehicle, powered by two lithium-ion battery packs of different capacity and voltage has been developed. The required Energy Management System (EMS) in this system controls the current flows of both packs independently by means of two individual dc-dc converters. It acts as an intermediary between energy storage (battery management systems-BMS) and the drivetrain controller on the vehicle control unit (VCU) as well as the on-board charger. This paper describes the most important tasks of the EMS and its interfaces to the BMS and the VCU. To validate the algorithms before integrating them into the vehicle prototype, a detailed Matlab / Simulink-model was created in the project. Test procedures and results from the simulation as well as experiences and comparisons from the real car are presented at the end.

Electroconvective Instability on Undulated Ion-selective Surface (파상형 이온 선택 표면상의 전기와류 불안정성)

  • Lee, Hyomin
    • Korean Chemical Engineering Research
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    • v.57 no.5
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    • pp.735-742
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    • 2019
  • In this work, the electrokinetic interactions between the undulated structure of an ion-selective membrane and electroconvective instability has been studied using numerical analysis. Using finite element method, electric field-ionic species transport-flow field were analyzed by fully-coupled manner. Through the numerical study, the Dukhin's mode as the mechanism of undulated surface for the electroconvective instability were proven. The Dukhin's mode which competes with Rubinstein's mode has roles of (i) decreasing transition voltage to overlimiting regime and (ii) non-linearly increasing of overlimiting current. Also, (iii) the mixing efficiency is enhanced by removal mechanism of high-frequency Fourier mode of the electroconvective instability. Conclusively, the undulated ion-selective surface would provide energy-efficient mechanism for ion-selective transport systems such as electrodialysis, electrochemical battery, etc.

Performance Analysis in Direct Internal Reforming Type of Molten Carbonate Fuel Cell (DIR-MCFC) according to Operating Conditions (직접내부개질형 용융탄산염 연료전지(DIR-MCFC)의 운전 조건에 따른 성능 분석)

  • JUNG, KYU-SEOK;LEE, CHANG-WHAN
    • Journal of Hydrogen and New Energy
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    • v.33 no.4
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    • pp.363-371
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    • 2022
  • In this study, the operation characteristics of the internal reforming type molten carbonate fuel cell (MCFC) were studied using computational fluid dynamics (CFD) analysis according to the steam to carbon ratio (S/C ratio), operating temperature, and gas utilization. From the simulation results, the distribution of gas composition due to the electrochemical reaction and the reforming reaction was predicted. The internal reforming type showed a lower temperature difference than the external reforming type MCFC. As the operating temperature decreased, less hydrogen was produced and the performance of the fuel cell also decreased. As the gas utilization rate decreased, more gas was injected into the same reaction area, and thus the performance of the fuel cell increased.

Physical Property Analysis of Composite Electrodes with Different Active Material Sizes and Densities using 3D Structural Modeling (3차원 구조 모델링을 이용한 활물질 입자 크기 및 전극 밀도에 따른 복합 전극 내 물리적 특성 분석)

  • Yang, Seungwon;Park, Joonam;Byun, Seoungwoo;Kim, Nayeon;Ryou, Myung-Hyun;Lee, Yong Min
    • Journal of the Korean Electrochemical Society
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    • v.23 no.2
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    • pp.39-46
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    • 2020
  • Composite electrodes for rechargeable batteries generally consist of active material, electric conductor, and polymeric binder. And their composition and distribution within the composite electrode determine the electrochemical activity in the electrochemical systems. However, it is not easy to quantify the physical properties of composite electrodes themselves using conventional experimental analysis tools. So, 3D structural modeling and simulation can be an efficient design tool by looking into the contact areas between particles and electric conductivity within the composite electrode. In this study, while maintaining the composition (LiCoO2 : Super P Li® : Polyvinylidene Fluoride (PVdF) = 93 : 3 : 4 by wt%) and loading level (13 mg cm-2) of the composite electrode, the effects of LiCoO2 size (10 ㎛ and 20 ㎛) and electrode density (2.8 g cm-3, 3.0 g cm-3, 3.2 g cm-3, 3.5 g cm-3, 4.0 g cm-3) on the physical properties are investigated using a GeoDict software. With this tool, the composite electrode can be efficiently designed to optimize the contact area and electric conductivity.

Modeling of the dynamic behavior of a 12-V automotive lead-acid battery (12V 차량용 납축전지의 동적 거동 모델링)

  • Kim, Sung Tae;Lee, Jeong Bin;Kim, Ui Seong;Shin, Chee Burm
    • Journal of Energy Engineering
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    • v.22 no.2
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    • pp.175-183
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    • 2013
  • For the optimal design of the vehicle electric system, it is important to have a reliable modeling tool to predict the dynamic behavior of the automotive battery. In this work, a one-dimensional modeling was carried-out to predict the dynamic behaviors of a 12-V automotive lead-acid battery. The model accounted for electrochemical kinetics and ionic mass transfer in a battery cell. In order to validate the modeling, modeling results were compared with the experiment data of the dynamic behaviors of the lead-acid batteries of two different capacities that were mounted on the automobiles manufactured by Hyundai Motor Company. The discharge behaviors were measured with various discharge rates of C/3, C/5, C/10, C/20 and combination. And dynamic behaviors of charge and discharge were measured. The voltage curves from the experiment and simulation were in good agreement. Based on the modeling, the distributions of the electrical potentials of the solid and solution phases, and the current density within the electrodes could be predicted as a function of charge and discharge time.

A Feasibility Study for a Stratospheric Long-endurance Hybrid Unmanned Aerial Vehicle using a Regenerative Fuel Cell System

  • Cho, Seong-Hyun;Cha, Moon-Yong;Kim, Minjin;Sohn, Young-Jun;Yang, Tae-Hyun;Lee, Won-Yong
    • Journal of Electrochemical Science and Technology
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    • v.7 no.1
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    • pp.41-51
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    • 2016
  • In the stratosphere, the air is stable and a photovoltaic (PV) system can produce more solar energy compared to in the atmosphere. If unmanned aerial vehicles (UAVs) fly in the stratosphere, the flight stability and efficiency of the mission are improved. On the other hand, the weakened lift force of the UAV due to the rarefied atmosphere can require more power for lift according to the weight and/or wing area of the UAV. To solve this problem, it is necessary to minimize the weight of the aircraft and improve the performance of the power system. A regenerative fuel cell (RFC) consisting of a fuel cell (FC) and water electrolysis (WE) combined PV power system has been investigated as a good alterative because of its higher specific energy. The WE system produces hydrogen and oxygen, providing extra energy beyond the energy generated by the PV system in the daytime, and then saves the gases in tanks. The FC system supplies the required power to the UAV at night, so the additional fuel supply to the UAV is not needed anymore. The specific energy of RFC systems is higher than that of Li-ion battery systems, so they have less weight than batteries that supply the same energy to the UAV. In this paper, for a stratospheric long-endurance hybrid UAV based on an RFC system, three major design factors (UAV weight, wing area and performance of WE) affecting the ability of long-term flight were determined and a simulation-based feasibility study was performed. The effects of the three design factors were analyzed as the flight time increased, and acceptable values of the factors for long endurance were found. As a result, the long-endurance of the target UAV was possible when the values were under 350 kg, above 150 m2 and under 80 kWh/kg H2.

Numerical Simulation of Lithium-Ion Batteries for Electric Vehicles (전기 자동차용 리튬이온전지 개발을 위한 수치해석)

  • You, Suk-Beom;Jung, Joo-Sik;Cheong, Kyeong-Beom;Go, Joo-Young
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.35 no.6
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    • pp.649-656
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    • 2011
  • A model for the numerical simulation of lithium-ion batteries (LIBs) is developed for use in battery cell design, with a view to improving the performances of such batteries. The model uses Newman-type electrochemical and transfer $theories^{(1,2)}$ to describe the behavior of the lithium-ion cell, together with the Levenberg-Marquardt optimization scheme to estimate the performance or design parameters in nonlinear problems. The mathematical model can provide an insight into the mechanism of LIB behavior during the charging/discharging process, and can therefore help to predict cell performance. Furthermore, by means of least-squares fitting to experimental discharge curves measured at room temperature, we were able to obtain the values of transport and kinetic parameters that are usually difficult to measure. By comparing the calculated data with the life-test discharge curves (SB LiMotive cell), we found that the capacity fade is strongly dependent on the decrease in the reaction area of active materials in the anode and cathode, as well as on the electrolyte diffusivity.

Mass Transfer Analysis of Metal-Supported and Anode-Supported Solid Oxide Fuel Cells (금속지지체형 고체산화물연료전지와 연료극지지체형 고체산화물연료전지의 물질전달 특성분석)

  • Park, Joon-Guen;Kim, Sun-Young;Bae, Joong-Myeon
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.34 no.3
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    • pp.317-324
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    • 2010
  • Metal-supported solid oxide fuel cells (SOFCs) have been developed to commercialize SOFCs. This new type of SOFC has high mechanical strength, but its mass transfer rate may be low due to the presence of a contact layer. In this study, the mass transfer characteristics of an anode-supported SOFC and a metal-supported SOFC are studied by performing numerical simulation. Governing equations, electrochemical reactions, and ceramic physical-property models are determined simultaneously; molecular diffusion and Knudsen diffusion are considered in mass transport analysis of porous media. The experimental results are compared with simulation data to validate the results of numerical simulation. The average current density of the metal-supported SOFC is 23% lower than that of the anode-supported SOFC. However, because of the presence of the contact layer, the metal-supported SOFC has a more uniform distribution than the anode-supported SOFC.

The Notch Filter Design for Mitigation Current Ripple of Fuel cell-PCS (연료전지용 PCS의 출력 전류 리플 개선을 위한 노치 필터 설계)

  • Kim, Seung-Min;Park, Bong-Hee;Choi, Ju-Yeop;Choy, Ick;Lee, Sang-Chul;Lee, Dong-Ha
    • Journal of the Korean Solar Energy Society
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    • v.32 no.6
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    • pp.106-112
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    • 2012
  • As a fuel cell converts the chemical energy of the fuel cell into electrical energy by electrochemical reaction, the fuel cell system is uniquely integrated technique including fuel processor, fuel cell stack, power conditioning system. The residential fuel cell-PCS(Power Conditioning System) needs to convert efficiently the DC current produced by the fuel cell into AC current using single-phase DC-AC inverter. A single-phase DC-AC inverter has naturally low frequency ripple which is twice frequency of the output current. This low frequency(120Hz) ripple reduces the efficiency of the fuel cell. This paper presents notch filter with IP voltage controller to reject specific 120Hz current ripple in single-phase inverter. The notch filter is designed that suppress just only specific frequency component and no phase delay. Finally, the proposed notch filter design method has been verified with computer simulation and experimentation.

Dynamic Model of a Passive Air-Breathing Direct Methanol Fuel Cell (수동급기 직접 메탄올 연료전지의 동적 모델)

  • Ha, Seung-Bum;Chang, Ikw-Hang;Cha, Suk-Won
    • 한국신재생에너지학회:학술대회논문집
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    • 2008.05a
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    • pp.33-36
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    • 2008
  • The transient behavior of a passive air breathing direct methanol fuel cell (DMFC) operated on vapor-feeding mode is studied in this paper. It generally takes 30 minutes after starting for the cell response to come to its steady-state and the response is sometimes unstable. A mathematical dynamic one-dimensional model for simulating transient response of the DMFC is presented. In this model a DMFC is decomposed into its subsystems using lumped model and divided into five layers, namely the anodic diffusion layer, the anodic catalyst layer, the proton exchange membrane (PEM), the cathodic catalyst layer and the cathodic diffusion layer. All layers are considered to have finite thickness, and within every one of them a set of differential-algebraic governing equations are given to represent multi-components mass balance, such as methanol, water, oxygen and carbon dioxide, charge balance, the electrochemical reaction and mass transport phenomena. A one-dimensional, isothermal and mass transport model is developed that captures the coupling between water generation and transport, oxygen consumption and natural convection. The single cell is supplied by pure methanol vapor from a methanol reservoir at the anode, and the oxygen is supplied via natural air-breathing at the cathode. The water is not supplied from external source because the cell uses the water created at the cathode using water back diffusion through nafion membrane. As a result of simulation strong effects of water transport were found out. The model analysis provides several conclusions. The performance drop after peak point is caused by insufficiency of water at the anode. The excess water at the cathode makes performance recovery impossible. The undesired crossover of the reactant methanol through the PEM causes overpotential at the cathode and limits the feeding methanol concentration.

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