13 research outputs found
A structural battery and its multifunctional performance
Engineering materials that can store electrical energy in structural load paths can revolutionize lightweight design across transport modes. Stiff and strong batteries that use solid-state electrolytes and resilient electrodes and separators are generally lacking. Herein, a structural battery composite with unprecedented multifunctional performance is demonstrated, featuring an energy density of 24 Wh kg-1 and an elastic modulus of 25 GPa and tensile strength exceeding 300 MPa. The structural battery is made from multifunctional constituents, where reinforcing carbon fibers (CFs) act as electrode and current collector. A structural electrolyte is used for load transfer and ion transport and a glass fiber fabric separates the CF electrode from an aluminum foil-supported lithium–iron–phosphate positive electrode. Equipped with these materials, lighter electrical cars, aircraft, and consumer goods can be pursued
In-situ activated hydrogen evolution by molybdate addition to neutral and alkaline electrolytes
Activation of the hydrogen evolution reaction (HER) by in-situ addition of Mo(VI) to the electrolyte has been studied in alkaline and pH neutral electrolytes, the latter with the chlorate process in focus. Catalytic molybdenum containing films formed on the cathodes during polarization were investigated using scanning electron microscopy (SEM), energy-dispersive X ray analysis (EDS), X-ray photoelectron spectroscopy (XPS), and X ray fluorescence (XRF). In-situ addition of Mo(VI) activates the HER on titanium in both alkaline and neutral electrolytes and makes the reaction kinetics independent of the substrate material. Films formed in neutral electrolyte consisted of molybdenum oxides and contained more molybdenum than those formed in alkaline solution. Films formed in neutral electrolyte in the presence of phosphate buffer activated the HER, but were too thin to be detected by EDS. Since molybdenum oxides are generally not stable in strongly alkaline electrolyte, films formed in alkaline electrolyte were thinner and probably co-deposited with iron. A cast iron molybdenum alloy was also investigated with respect to activity for HER. When polished in the same way as iron, the alloy displayed a similar activity for HER as pure iron
Cost Control and Revenue Generation: The Case of Public-housing Companies' Experiences in Sweden
Lindbergh L., Larsson C.-G. and Wilson T. L. (2004) Cost control and revenue generation: the case of public-housing companies' experiences in Sweden, Regional Studies38, 803-815. Increased competition for funds associated with the provision of public-sector housing, stock privatization, and attempts to introduce more tenant-centred and effective housing management services are trends seen in social housing throughout the European Union. Consequently, studies have been done that compare programmes worldwide and in Europe, or analyse changes in single countries. The Swedish system has received attention because of its long-term viability. An ordinary least-squares analysis of financial information from providers in this system has been made with special regard to revenue generation capabilities, the ability to remain profitable, and the retention of asset values for both level and first difference approaches. If one general lesson can be drawn from the empirical results, it would be that expenditures on consolidated maintenance are associated not only with short- term rental revenues, but also undoubtedly with long-term viability. Further, first difference results suggested that negotiated rents produced operating profits that kept pace with revenues over that period of the study. The results should be especially relevant to the interests of a wide range of local governments where public housing is of concern. In particular, those individuals bearing greater responsibility for running self-sufficient systems and also policy-makers interested in running efficient, effective systems should be interested in these observations. Lindbergh L., Larsson C.-G. et Wilson T. L. (2004) La maitrise des couts et la production des revenus: etude de cas des logements sociaux en Suede, Regional Studies38, 803-815. La competition accrue pour les fonds associes a l'offre des logements sociaux, la privatisation du parc de logements, et les tentatives de fournir des services logement et de gestion plus efficaces et plus centres sur le locataire, representent des tendances qui sont evidentes partout dans l'Union europeenne. Par consequent, des etudes ont ete menees qui comparent des programmes d'action elabores sur le plan mondial aux programmes d'action d'envergure europeenne, ou bien qui analysent des changements dans des pays individuels. Le systeme suedois a attire beaucoup d'attention a cause de sa validite a long terme. On fait une estimation par les moindres carres ordinaire a partir des donnees financieres provenant des prestataires de services dans ce systeme, avec un egard particulier pour la capacite a produire des revenus, a assurer la rentabilite, et a maintenir la valeur des actifs immobiliers quant aux approches qui portent sur le niveau et sur la difference d'ordre premier. Une lecon a tirer potentiellement des resultats empiriques c'est la suivante. Les depenses pour l'entretien consolide s'associent non seulement aux revenus locatifs a court terme, mais aussi a la validite a long terme. En outre, les resultats provenant de l'approche qui porte sur la difference d'ordre premier laissent supposer que les loyers negocies produisent des resultats d'exploitation qui arrivent a suivre les revenus sur la periode etudiee. Ces resultats devraient avoir un rapport tres etroit aux interets de tout un eventail d'administrations ou les logements sociaux laissent a inquieter. En particulier, ceux qui sont charges de la direction des systemes autosuffisants ainsi que les decideurs interesses par la mise en oeuvre des systemes efficaces, devraient noter ces remarques. Lindbergh L., Larsson C.-G. und Wilson T. L. (2004) Kostenregulierung und Schaffung von Steuereinkommen: Erfahrungen der Gesellschaften fur Wohnungsfursorge in Schweden, Regional Studies38, 803-815. Zunehmende Konkurenz bei der Vergebung von Mitteln fur die Schaffung von Wohnraum durch die offentliche Hand, Verkauf bestehenden Wohnraums an private Eigentumer und Versuche, vermehrt auf Mieter zugeschnittene und effektive Hausverwaltungsdienste sind Tendenzen, die in der ganzen Europaischen Union auf dem Gebiet der Bereitstellung von Sozialwohnungen zu beobachten sind. Infolgedessen hat man Untersuchungen durchgefuhrt, die Programme auf der ganzen Welt und in Europa miteinander vegleichen, oder anderungen in einzelnen Landern. Dank seiner langfristigen Durchfuhrbarkeit hat das schwedische System Aufmerksamkeit erregt. Eine Analyse der gewohnlichen Methode der kleinsten Quadrate der Finanzinformation von Mittel zur Verfugung stellenden Korperschaften in diesem System wurde bei besonderer Berucksichtigung seiner Fahigkeiten der Steuerbeschaffung, der Fahigkeit wirtschaftlich zu bleiben, und der Erhaltung von Vermogungswerten fur gleichbleibende Ansatze wie auch erstmals abweichende Ansatze durchgefuhrt. Wenn eine allgemeingultige Lehre aus den empirischen Ergebnissen gezogen werden kann, so ware es die, dass Ausgaben fur Dauerpflege nicht nur mit kurzfristigen Mieteinkommen, sondern zweifellos auch mit langfristiger Lebensfahigkeit zu tun haben. Weiterhin legen erstmalig abweichende Ergebnisse nahe, dass vereinbarte Mieten laufend Gewinne abwerfen, die im fur diese Studie angesetzten Zeitraum mit den Steuern Schritt hielten. Diese Ergebnisse sollten besonders den Interessen der sehr verschiedenartigen Ortsverwaltungen sachdienlich sein, die sich mit offentlichem Wohnungsbau und - verwaltung befassen, insbesondere diejenigen, die fur Bereitstellung und Erhaltung eines sich selbst tragenden Systems hauptverantwortlich sind, wie auch Sozialpolitiker, die an gut funktionierenden, effektiven Systemen interessiert sind, diesen Befunden Aufmerksamkeit schenken durften. Lindbergh L., Larsson C.-G. y Wilson T. L. (2004) Control de costes y generacion de beneficios: el caso de las experiencias de las 'empresas constructoras de vivienda social' en Suecia, Regional Studies38, 803-815. El incremento de la competicion por fondos asociados con la provision de vivienda social, la privatizacion de capital y los intentos destinados a introducir servicios de administracion de la vivienda mas orientados hacia el arrendatario y mas eficaces son tendencias que se observan en la vivienda social a traves de la Union Europea. Consecuentemente, se han llevado a cabo estudios que comparan programas en todo el mundo y en Europa, o que analizan los cambios en paises individuales. El sistema sueco ha recibido atencion debido a su viabilidad a largo plazo. Se ha realizado un analisis ordinary least squares de la informacion financiera de los proveedores en este sistema especialmente con respecto a las capacidades de generacion de beneficios, la habilidad de permacer rentable, y la retencion de valor de los activos tanto para enfoques de nivel y de primera diferencia. Si se puediera derivar una leccion general de estos resultados empiricos, esta seria que los gastos en el mantenimiento consolidado no estan solamente asociados con los beneficios derivados de la renta a corto-plazo, pero sin duda tambien con la viabilidad a largo plazo. Ademas, los resultados de primera diferencia sugirieron que las rentas negociadas producieron beneficios de operacion que siguieron el ritmo de los beneficios a lo largo del periodo de estudio. Estos resultados deberian ser especialmente relevantes para los intereses de un amplio grupo de gobiernos locales donde la vivienda social es una causa de preocupacion. Particularmente, aquellos individuos que soportan una mayor responsabilidad en la direccion de sistemas autosuficientes y tambien los disenadores de politicas que estan interesados en dirigir sistemas efectivos y eficaces deberian estar interesados en estas observaciones.Public housing, Swedish system, Ordinary least squares, Quantitative analyses, Professional efficiency,
Impedance spectroscopy as a diagnostic tool for monitoring ageing in a lithium-ion battery for HEV applications
Impedance as a diagnostic tool for monitoring ageing in a lithium-ion battery for HEV application
Diagnosis and prognosis of battery degradation through re-evaluation and Gaussian process regression of electrochemical model parameters
Lithium-ion battery degradation is complex, and many mechanisms occur concurrently. In-depth degradation is traditionally investigated by post-mortem characterization in lab-settings. If mechanisms could instead be identified in-operando, utilization could be adjusted, and battery lifetime extended. We investigate changes in electrochemical model parameters during battery testing and their correlation with degradation observed in a traditional post-mortem characterization. Commercial batteries are cycle-aged using different stationary storage service cycles and a novel reference performance test is applied intermittently. This test is based on current profiles optimally designed with respect to maximized sensitivity for individual electrochemical parameters and embedded within a charging procedure. Usage dependency of parameter trajectories over the course of ageing is demonstrated and coupled to observed micro-structural changes. Subsequently, the parameter trajectories are extrapolated using Gaussian Process Regression for physics-based state-of-health estimation and remaininguseful-life prediction. We demonstrate and validate estimation of full cell performance under constant load at a later state in life
Novel Field Test Equipment for Lithium-Ion Batteries in Hybrid Electrical Vehicle Applications
In-Situ Analysis of Electrodes Using Fine-Tuned Poly(Terphenyl Piperidinium) Ionomers in Anion Exchange Membrane Fuel Cells
Fast-charging effects on ageing for energy-optimized automotive LiNi1/3Mn1/3Co1/3O2/graphite prismatic lithium-ion cells
The reactions in energy-optimized 25 Ah prismatic NMC/graphite lithium-ion cell, as a function of fast charging (1C-4C), are more complex than earlier described. There are no clear charging rate dependent trends but rather different mechanisms dominating at the different charging rates. Ageing processes are faster at 3 and 4C charging. Cycling with 3C-charging results in accelerated lithium plating but the 4C-charging results in extensive gas evolution that contribute significantly to the large cell impedance rise. Graphite exfoliation and accelerated lithium inventory loss point to the graphite electrode as the source of the gas evolution. The results are based on careful post-mortem analyses of electrodes using: scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and electrochemical impedance spectroscopy (EIS). SEM results show particle cracking independent of the charging rate used for the cycling. XPS and EIS generally indicate thicker surface film and larger impedance, respectively, towards the edge of the jellyrolls. For the intended application of a battery electric inner-city bus using this type of cell, charging rates of 3C and above are not feasible, considering battery lifetime. However, charging rates of 2C and below are too slow from the point of view of practical charging time