28 results found
Huang M, Finlayson E, Liu H, et al., The current and future prospects for vanadium flow batteries in China, International Flow Battery Forum
Chen X, Liu X, Childs P, et al., 2017, A Low Cost Desktop Electrochemical Metal 3D Printer, Advanced Materials Technologies, Pages: 1700148-1700148, ISSN: 2365-709X
Gupta G, Wu B, Mylius S, et al., 2017, A systematic study on the use of short circuiting for the improvement of proton exchange membrane fuel cell performance, INTERNATIONAL JOURNAL OF HYDROGEN ENERGY, Vol: 42, Pages: 4320-4327, ISSN: 0360-3199
Liu X, Wu B, Brandon N, et al., 2017, Tough Ionogel-in-Mask Hybrid Gel Electrolytes in Supercapacitors with Durable Pressure and Thermal Tolerances, ENERGY TECHNOLOGY, Vol: 5, Pages: 220-224, ISSN: 2194-4288
Wu B, Myant C, Weider SZ, 2017, The value of additive manufacturing: future opportunities, Briefing paper, 2
Wu B, Offer G, 2017, Environmental Impact of Hybrid and Electric Vehicles, Environmental Impacts of Road Vehicles : Past, Present and Future, Editors: Harrison, Hester, Publisher: Royal Society of Chemistry
Hybrid and electric vehicles play a critical role in reducing global greenhouse gas emissions, with transport estimated to contribute to 14% of the 49 GtCO2eq produced annually. Analysis of only the conversion efficiency of powertrain technologies can be misleading, with pure battery electric and hybrid vehicles reporting average efficiencies of 92% and 35% in comparison with 21% for internal combustion engine vehicles. A fairer comparison would be to consider the well-to-wheel efficiency, which reduces the numbers to 21–67%, 25% and 12%, respectively. The large variation in well-to-wheel efficiency of pure battery electric vehicles highlights the importance of renewable energy generation in order to achieve true environmental benefits. When calculating the energy return on investment of the various technologies based on the current energy generation mix, hybrid vehicles show the greatest environmental benefits, although this would change if electricity was made with high amounts of renewables. In an extreme scenario with heavy coal generation, the CO2eq return on investment can actually be negative for pure electric vehicles, highlighting the importance of renewable energy generation further. The energy impact of production is generally small (∼6% of lifetime energy) and, similarly, recycling is of a comparable magnitude, but it is less well studied.
Ibrahim KA, Wu B, Brandon NP, 2016, Electrical conductivity and porosity in stainless steel 316L scaffolds for electrochemical devices fabricated using selective laser sintering, MATERIALS & DESIGN, Vol: 106, Pages: 51-59, ISSN: 0264-1275
Li J, wu BILLY, Myant CONNOR, 2016, The Current Landscape for Additive Manufacturing Research
Merla Y, Wu B, Yufit V, et al., 2016, Novel application of differential thermal voltammetry as an in-depth state-of-health diagnosis method for lithium-ion batteries, JOURNAL OF POWER SOURCES, Vol: 307, Pages: 308-319, ISSN: 0378-7753
Merla Y, Wu B, Yufit V, et al., 2016, Extending battery life: A low-cost practical diagnostic technique for lithium-ion batteries, JOURNAL OF POWER SOURCES, Vol: 331, Pages: 224-231, ISSN: 0378-7753
Patsios C, Wu B, Chatzinikolaou E, et al., 2016, An integrated approach for the analysis and control of grid connected energy storage systems, JOURNAL OF ENERGY STORAGE, Vol: 5, Pages: 48-61, ISSN: 2352-152X
Wu B, Parkes MA, de Benedetti L, et al., 2016, Real-time monitoring of proton exchange membrane fuel cell stack failure, JOURNAL OF APPLIED ELECTROCHEMISTRY, Vol: 46, Pages: 1157-1162, ISSN: 0021-891X
Dewage HH, Wu B, Tsoi A, et al., 2015, A novel regenerative hydrogen cerium fuel cell for energy storage applications, JOURNAL OF MATERIALS CHEMISTRY A, Vol: 3, Pages: 9446-9450, ISSN: 2050-7488
Lomberg M, Boldrin P, Tariq F, et al., 2015, Additive manufacturing for solid oxide cell electrode fabrication, Pages: 2119-2127, ISSN: 1938-5862
© The Electrochemical Society. Additive manufacturing can potentially offer a highly-defined electrode microstructure, as well as fast and reproducible electrode fabrication. Selective laser sintering is an additive manufacturing technique in which three-dimensional structures are created by bonding subsequent layers of powder using a laser. Although selective laser sintering can be applied to a wide range of materials, including metals and ceramics, the scientific and technical aspects of the manufacturing parameters and their impact on microstructural evolution during the process are not well understood. In the present study, a novel approach for electrode fabrication using selective laser sintering was evaluated by conducting a proof of concept study. A Ni-patterned fuel electrode was laser sintered on an yttria-stabilized zirconia substrate. The optimization process of laser parameters (laser sintering rate and laser power) and the electrochemical results of a full cell with a laser sintered electrode are presented. The challenges and prospects of using selective laser sintering for solid oxide cell fabrication are discussed.
Wu B, Brandon NP, Yufit V, et al., 2015, HYBRID ELECTROCHEMICAL ENERGY DEVICE, WO/2015/150784
The present invention generally relates to the field of devices which are capable of storing and delivering electricity. In particular, the invention relates to a hybrid redox flow battery (HyRFB) capable of operating in a power delivery mode in which it generates electrical power by the reaction of electrochemically active species at a first and second electrode and in an energy storage mode in which it consumes electrical power to generate at least one electrochemically active species, the HyRFB comprising: • a reversible first electrode in a first electrode compartment containing a first aqueous electrolyte, • a reversible second electrode in a second electrode compartment containing a second aqueous electrolyte; and • a conduit arrangement configured, in said power delivery mode, for carrying electrochemically active species to the first electrode and, in an energy storage mode, for carrying generated electrochemically active species away from the first electrode; wherein the second electrode comprises a material that is capable of reversibly taking up and releasing alkali metal ions or alkaline earth metal ions during the said modes of operation, and wherein the second electrolyte comprises the alkali metal ions or the alkaline earth metal ions.
Wu B, Yufit V, Merla Y, et al., 2015, Differential thermal voltammetry for tracking of degradation in lithium-ion batteries, Journal of Power Sources, Vol: 273, Pages: 495-501, ISSN: 1873-2755
Monitoring of lithium-ion batteries is of critical importance in electric vehicle applications in order to manage the operational condition of the cells. Measurements on a vehicle often involve current, voltage and temperature which enable in-situ diagnostic techniques. This paper presents a novel diagnostic technique, termed differential thermal voltammetry, which is capable of monitoring the state of the battery using voltage and temperature measurements in galvanostatic operating modes. This tracks battery degradation through phase transitions, and the resulting entropic heat, occurring in the electrodes. Experiments to monitor battery degradation using the new technique are compared with a pseudo-2D cell model. Results show that the differential thermal voltammetry technique provides information comparable to that of slow rate cyclic voltammetry at shorter timescale and with load conditions easier to replicate in a vehicle.
Tariq F, Yufit V, Eastwood DS, et al., 2014, In-Operando X-ray Tomography Study of Lithiation Induced Delamination of Si Based Anodes for Lithium-Ion Batteries, ECS ELECTROCHEMISTRY LETTERS, Vol: 3, Pages: A76-A78, ISSN: 2162-8726
Troxler Y, Wu B, Marinescu M, et al., 2014, The effect of thermal gradients on the performance of lithium-ion batteries, JOURNAL OF POWER SOURCES, Vol: 247, Pages: 1018-1025, ISSN: 0378-7753
Wu B, Brandon NP, Yufit V, et al., 2014, A segmented fuel cell-battery passive hybrid system, WO/2014/195736
An apparatus for supplying electrical energy to a varying load is disclosed. The apparatus comprises fuel cells and energy storage devices. A fuel cell subset comprises one or a plurality of series-connected ones of the fuel cells, having a first no-load open- circuit potential thereacross and is connected in parallel with an energy storage device subset comprising one or a plurality of series-connected ones of the energy storage devices, having a second no-load open-circuit potential thereacross, to form a unit. The unit cell is connected in series or parallel with at least one other unit cell. The fuel cells in the unit cell and the at least one other unit cell are fuel cells of the same fuel cell stack. The arrangement is such that first no-load open-circuit potential and the second no-load open circuit potential are substantially balanced.
Wu B, Parkes MA, Yufit V, et al., 2014, Design and testing of a 9.5 kWe proton exchange membrane fuel cell-supercapacitor passive hybrid system, INTERNATIONAL JOURNAL OF HYDROGEN ENERGY, Vol: 39, Pages: 7885-7896, ISSN: 0360-3199
Marinescu M, Wu B, Von Srbik M, et al., 2013, The effect of thermal gradients on the performance of battery packs in automotive applications, IET Conference Publications, Vol: 2013
Thermal gradients arising inside a battery pack for automotive applications are calculated for 200 A discharge via a multiparticle thermal-electrochemical coupled high fidelity model for a 12P7S 4.8 Ah cell pack. The effect of such gradients at the cell level are studied in a first approximation under a corresponding discharge at 15 A, by discretising the cell into units at fixed temperatures throughout the discharge. The immediate time evolution of load distribution through the various parts of the cell shows a complex behaviour, dependent on parameters such as temperatures, state of charge and load characteristics.
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.
Wu B, Yufit V, Marinescu M, et al., 2013, Coupled thermal-electrochemical modelling of uneven heat generation in lithium-ion battery packs, JOURNAL OF POWER SOURCES, Vol: 243, Pages: 544-554, ISSN: 0378-7753
Offer GJ, Yufit V, Howey DA, et al., 2012, Module design and fault diagnosis in electric vehicle batteries, JOURNAL OF POWER SOURCES, Vol: 206, Pages: 383-392, ISSN: 0378-7753
Wu B, Matian M, Offer GJ, 2012, Hydrogen PEMFC system for automotive applications, International Journal of Low-Carbon Technologies, Vol: 7, Pages: 28-37, ISSN: 1748-1317
A balance of plant (BOP) system for a 9.5-kWe Nedstack P9.5-75 low-temperature proton exchange membrane fuel cell (FC) stack was tested up to a power of 2 kWe. The system has been designed to act as a range extender for a series hybrid electric vehicle driven under urban duty cycles. Vehicle simulations have estimated that an average gross power requirement of 4 kWe is needed from the FC, whilst simulations of the FC stack and BOP components have allowed for characterisation of transient behaviour and performance degradation. © The Author 2012. Published by Oxford University Press. All rights reserved.
Wu B, Offer GJ, Yufit V, et al., 2012, Fault analysis in battery module design for electric and hybrid vehicles
In this paper systems integration issues, such as electrical and thermal design and management of full battery packs - often containing hundreds of cells - are discussed. The design and construction of a 9 kWh battery pack for a motorsports application is used as an example. The pack contained 504 lithium cells arranged into 2 sidepods, each containing 3 modules, with each module in a 12P7S configuration. This paper focuses on describing problems related to cells being connected in parallel, known as massively parallel packs. We also demonstrate how a full vehicle test can be used to identify malfunctioning strings of cells for further investigation. It is shown that normal inter-cell contact resistances can cause 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, which was able to reproduce the results that were seen in experimental tests. 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, and ultimately, some cells discharging and aging more quickly than others and jeopardising the energy storage capacity and lifetime of the entire pack.
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