424 results found
Cooper SJ, Eastwood DS, Gelb J, et al., 2013, Image Based Modelling of of Microstructural Heterogeneity in LiFePO4 Electrodes for Li-ion Batteries, Journal of Power Sources, Vol: 247, Pages: 1033-1039, ISSN: 0378-7753
Battery and fuel cell simulations commonly assume that electrodes are macro-homogeneous and isotropic. These simulations have been used to successfully model performance, but give little insight into predicting failure. In Li-ion battery electrodes, it is understood that local tortuosity impacts charging rates, which may cause increased degradation. This report describes a novel approach to quantifying tortuosity based on a heat transfer analogy applied to X-ray microscopy data of a commercially available LiFePO4 electrode. This combination of X-ray imaging and image-based simulation reveals the microscopic performance of the electrode; notably, the tortuosity was observed to vary significantly depending on the direction considered, which suggests that tortuosity might best be quantified using vectors rather than scalars.
Mook WT, Aroua MK, Chakrabarti MH, et al., 2013, The application of nano-crystalline PbO2 as an anode for the simultaneous bio-electrochemical denitrification and organic matter removal in an up-flow undivided reactor, ELECTROCHIMICA ACTA, Vol: 94, Pages: 327-335, ISSN: 0013-4686
Lanzini A, Leone P, Guerra C, et al., 2013, Durability of anode supported Solid Oxides Fuel Cells (SOFC) under direct dry-reforming of methane, CHEMICAL ENGINEERING JOURNAL, Vol: 220, Pages: 254-263, ISSN: 1385-8947
Ruiz-Trejo E, Boldrin P, Lubin A, et al., 2013, Silver-ceria composites for oxygen separation from air, 224th Electrochemical society meeting
Clague R, Marquis AJ, Brandon NP, 2013, Time independent and time dependent probability of failure of solid oxide fuel cells by stress analysis and the Weibull method, JOURNAL OF POWER SOURCES, Vol: 221, Pages: 290-299, ISSN: 0378-7753
Guerra C, Lanzini A, Leone P, et al., 2013, Comparison of the catalytic properties of SOFC anode supports under dry reforming of methane, Pages: 73-74
Copyright © 2013 Delta Energy and Environment. The work investigates the catalytic properties of different SOFC anode substrates towards the chemical conversion of methane and carbon dioxide into H2 and CO-rich mixtures. The analysis is carried out by means of experiments in micro-reactor configuration. A mass spectrometer is provided to analyze the composition of the gas mixture leaving the reactor and thus allowing the evaluation of methane conversion rate. Furthermore, Temperature Programmed Oxidation (TPO) experiments are performed on the anode samples aiming at the analysis of material activity towards the cracking reaction of methane. Anode substrates based on different materials and microstructures are taken into account. The work features the effect of materials' composition and microstructure on the methane conversion rate and carbon cracking.
Somalu MR, Muchtar A, Baboli MG, et al., 2013, Understanding the Relationship between Ink Rheology and Film Properties for Screen-Printed Nickel/Scandia-Stabilized-Zirconia Anodes, 13th International Symposium on Solid Oxide Fuel Cells (SOFC-XIII), Publisher: ELECTROCHEMICAL SOC INC, Pages: 1321-1330, ISSN: 1938-5862
Mazur C, Contestabile M, Offer GJ, et al., 2013, Understanding the automotive industry: German OEM behaviour during the last 20 years and its implications, World Electric Vehicle Journal, Vol: 6, Pages: 1054-1067, ISSN: 2032-6653
© 2013 WEVA Page. This work presents a study of how the automotive industry has responded in the last 20 years to pressures driven by economic and environmental issues, and by the transition towards electric mobility. Timelines for the major German automotive OEMs are presented to understand the industry's behaviour in the past in order to design suitable policies that are appropriate to reach future goals around the electrification of road transport. Based upon a comparison of the pressures arising in the automotive sector and the companies' behaviour with regard to technology choice and R&D, a set of hypotheses concerning this behaviour is then presented.
Maher RC, Duboviks V, Offer G, et al., 2013, In-operando Raman Characterization of Carbon Deposition on SOFC Anodes, 13th International Symposium on Solid Oxide Fuel Cells (SOFC-XIII), Publisher: ELECTROCHEMICAL SOC INC, Pages: 1619-1626, ISSN: 1938-5862
Lomberg M, Ruiz-Trejo E, Offer G, et al., 2013, Characterization of a Novel Ni-impregnated GDC Electrode for Solid Oxide Fuel Cell and Electrolysis Cell Applications, SOLID OXIDE FUEL CELLS 13 (SOFC-XIII), Vol: 57, Pages: 1349-1357, ISSN: 1938-5862
Parkes M, Refson K, d'Avezac M, et al., 2013, Determining Surface Chemistry and Vibrational Properties of SOFC Anode Materials Through ab initio Calculations, SOLID OXIDE FUEL CELLS 13 (SOFC-XIII), Vol: 57, Pages: 2419-2427, ISSN: 1938-5862
Wu B, Yufit V, Campbell J, et al., 2013, Simulated and experimental validation of a fuel cell-supercapacitor passive hybrid system for electric vehicles, IET Conference Publications, Vol: 2013
The concept of a fuel cell-supercapacitor hybrid system involves the direct coupling of the two devices to achieve the same benefits of hybridisation but without the need for costly DCDC converters. Using an experimentally validated steady state fuel cell model and a transmission line based supercapacitor model, it has been shown that the passive hybridisation allows for efficiency gains of approximately 16% compared to a pure fuel cell system. Under load, the supercapacitors meets the peak power requirement due to their lower impedance giving the FC time to ramp up. Under no load conditions, the fuel cell gradually charges the supercapacitors back to the steady state thermodynamic equilibrium potential. A fast fourier transform analysis of the respective loads under an automotive drive cycle showed that the supercapacitors act as a low pass filter, reducing the magnitude of load oscillations from the fuel cell. This therefore addresses two of the main modes of fuel cell degradation in automotive applications: rapid power cycling and no load idling.
Maskell WC, Brett DJL, Brandon NP, 2013, Improvements to Zirconia Thick-Film Oxygen Sensors, 17th Conference on Sensors and Their Applications, Publisher: IOP PUBLISHING LTD, ISSN: 1742-6588
Duboviks V, Maher RC, Offer G, et al., 2013, In-Operando Raman Spectroscopy Study of Passivation Effects on Ni-CGO Electrodes in CO2 Electrolysis Conditions, 13th International Symposium on Solid Oxide Fuel Cells (SOFC-XIII), Publisher: ELECTROCHEMICAL SOC INC, Pages: 3111-3117, ISSN: 1938-5862
Yufit V, Hale B, Matian M, et al., 2013, Development of a Regenerative Hydrogen-Vanadium Fuel Cell for Energy Storage Applications, JOURNAL OF THE ELECTROCHEMICAL SOCIETY, Vol: 160, Pages: A856-A861, ISSN: 0013-4651
Troxler Y, Wu B, Marinescu M, et al., 2013, The effect of thermal gradients on the performance of lithium ion batteries, Journal of Power Sources, Pages: accepted-accepted, ISSN: 0378-7753
Abstract An experimental apparatus is described, in which Peltier elements are used for thermal control of lithium-ion cells under isothermal and non-isothermal conditions, i.e. to induce and maintain thermal gradients. Lithium-ion battery packs for automotive applications consist of hundreds of cells, and depending on the pack architecture, individual cells may experience non-uniform thermal boundary conditions. This paper presents the first study of the impact of artificially induced thermal gradients on cell performance. The charge transfer resistance of a 4.8 Ah is verified to have a strong temperature dependence following the Arrhenius law. Thermal cycling of the cell, combined with slow rate cyclic voltammetry, allows to rapidly identify phase transitions in electrodes, due to the thermal effect of entropy changes. A cell with a temperature gradient maintained across is found to have a lower impedance than one held at the theoretical average temperature. This feature is attributed to details of the inner structure of the cell, and to the non-linear temperature dependence of the charge transfer resistance.
Solid oxide fuel cells (SOFCs) have many advantages when compared to other fuel cell technologies, particularly for distributed stationary applications. As a consequence they are becoming ever more economically competitive with incumbent energy solutions. However, as with all technologies, improvements in durability, efficiency and cost is required before they become feasible alternatives. Such improvements are enabled through improved understanding of the critical material interactions occurring during operation. Raman spectroscopy is a noninvasive and non-destructive optical characterization tool which is ideally suited to the study of these critical chemical processes occurring within operational SOFCs. In this paper we will discuss advantages of using Raman characterization for understanding these important chemical processes occurring within SOFCs. We will present the specific examples of the type of measurement possible and discuss the direction of future research. © 2012 Materials Research Society.
Mazur C, Contestabile M, Offer G, et al., 2012, Comparing electric mobility policies to transition science: Transition management already in action?, Pages: 123-128, ISSN: 2165-4387
Driven by sustainability issues as well as economic aspects, governments have been creating and applying policies and regulations with the aim of shifting national personal transport towards electric mobility. In this context, transition science offers insights into the relevant socio-technological systems and the process of transition. This paper gives an overview of transition science, and furthermore presents current policy making by the UK and German governments that aim to manage the shift to electric mobility. A comparison of the two different policies with transition science shows that there is an overlap between the applied policy making and theory, especially for the case of the UK. Although both governments do not explicitly follow transition management their actions can be explained with the help of transition science. However, it should be noted that transition science is still a young field which needs to be further developed in order to provide policy makers with tools that enable them to manage such transitions. ©2012 IEEE.
Iora P, Taher MAA, Chiesa P, et al., 2012, A one dimensional solid oxide electrolyzer-fuel cell stack model and its application to the analysis of a high efficiency system for oxygen production, CHEMICAL ENGINEERING SCIENCE, Vol: 80, Pages: 293-305, ISSN: 0009-2509
Clague R, Marquis AJ, Brandon NP, 2012, Finite element and analytical stress analysis of a solid oxide fuel cell, JOURNAL OF POWER SOURCES, Vol: 210, Pages: 224-232, ISSN: 0378-7753
Konda NVSNM, Shah N, Brandon NP, 2012, Dutch hydrogen economy: evolution of optimal supply infrastructure and evaluation of key influencing elements, ASIA-PACIFIC JOURNAL OF CHEMICAL ENGINEERING, Vol: 7, Pages: 534-546, ISSN: 1932-2135
Hawkes AD, Staffell I, Bergman N, et al., 2012, A Change of Scale? Prospects for Distributed Energy Resources, Energy 2050, Editors: Skea, Ekins, Winskel, London, UK, Publisher: Earthscan
Shearing PR, Bradley RS, Gelb J, et al., 2012, Exploring microstructural changes associated with oxidation in Ni-YSZ SOFC electrodes using high resolution X-ray computed tomography, SOLID STATE IONICS, Vol: 216, Pages: 69-72, ISSN: 0167-2738
Brightman E, Maher R, Offer GJ, et al., 2012, Designing a miniaturised heated stage for in situ optical measurements of solid oxide fuel cell electrode surfaces, and probing the oxidation of solid oxide fuel cell anodes using in situ Raman spectroscopy, REVIEW OF SCIENTIFIC INSTRUMENTS, Vol: 83, ISSN: 0034-6748
Brandon N, 2012, Can we kick our petrol pump habit?, MATERIALS TODAY, Vol: 15, Pages: 182-182, ISSN: 1369-7021
Somalu MR, Brandon NP, 2012, Rheological Studies of Nickel/Scandia-Stabilized-Zirconia Screen Printing Inks for Solid Oxide Fuel Cell Anode Fabrication, JOURNAL OF THE AMERICAN CERAMIC SOCIETY, Vol: 95, Pages: 1220-1228, ISSN: 0002-7820
Offer GJ, Yufit V, Howey DA, et al., 2012, Module design and fault diagnosis in electric vehicle batteries, Journal of Power Sources
Systems integration issues, such as electrical and thermal design and management of full battery packs–often containing hundreds of cells–have been rarely explored in the academic literature. In this paper we discuss the design and construction of a 9 kWh battery pack for a motorsports application. The pack contained 504 lithium cells arranged into 2 sidepods, each containing 3 modules, with each module in a 12P7S configuration. This paper focuses particularly on testing the full battery pack and diagnosing subsequent problems related to cells being connected in parallel. We demonstrate how a full vehicle test can be used to identify malfunctioning strings of cells for further investigation. After individual cell testing it was concluded that a single high inter-cell contact resistance was causing currents to flow unevenly within the pack, leading to cells being unequally worked. This is supported by a Matlab/Simulink model of one battery module, including contact resistances. Over time the unequal current flowing through cells can lead to significant differences in cells’ state of charge and open circuit voltages, large currents flowing between cells even when the load is disconnected, cells discharging and aging more quickly than others, and jeopardise capacity and lifetime of the pack.
Lorente E, Millan M, Brandon NP, 2012, Use of gasification syngas in SOFC: Impact of real tar on anode materials, INTERNATIONAL JOURNAL OF HYDROGEN ENERGY, Vol: 37, Pages: 7271-7278, ISSN: 0360-3199
Wu B, Offer GJ, Yufit V, et al., 2012, Fault analysis in battery module design for electric and hybrid vehicles, Power Electronics, Machines and Drive
Brett DJL, Manage M, Agante E, et al., 2012, Fuels and fuel processing for low temperature fuel cells, Polymer Electrolyte Membrane and Direct Methanol Fuel Cell Technology: Fundamentals and Performance of Low Temperature Fuel Cells, Pages: 3-26, ISBN: 9781845697730
This chapter examines the role of the fuel in the operation, performance and degradation of fuel cells. The range of fuels and impurities that are of relevance to low-temperature fuel cells are discussed and the performance from a thermodynamic perspective is analysed. As a route to hydrogen, various fuel processing options are considered along with an overview of the major storage techniques. Issues associated with alternative fuels are covered along with the deleterious properties of fuels and their impurities. © 2012 Woodhead Publishing Limited All rights reserved.
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