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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
71

Om packmaterial för transport av litiumjonbatterier : Brandegenskaper och arbetsmiljö / On packing material for transport of lithium-ion batteries : Fire properties and working environment

Hansson, Petter, Ohlsson, Sanna January 2022 (has links)
As the climate issue has affected most vehicle manufacturers, the number of electric cars in the world has increased in recent years. Scania's goal is that by 2030, 50 % of all their trucks sold in Europe will be powered by electricity. There are currently legal requirements for how transportation of batteries by road is allowed, depending on if the batteries are damaged, defective or prototype batteries. Scania currently has a method to transport these batteries. The working method consists of a safety box that is filled with the packing material Pyrobubbles in which the batteries are placed. However, Scania wants a better understanding of the function of Pyrobubbles, the safety box and its advantages and disadvantages, as well as whether there are better solutions. The work therefore intends to sort out these issues. In addition to reviewing the thermal properties of the materials, the work has been carried out from a SHE perspective on Scania’s request. This means that safety, health and the environment are taken into account. A literature study was conducted to investigate which alternative packaging materials were available as option to Pyrobubbles, as well as other manufacturers that are available for the safety box. Seven different packaging materials have been examined in the report, these are; absol, sorbix, vermiculite, sand, Pyrobubbles, glass- and stone wool. Two experimental studies were performed to investigate the properties of packing materials. All materials were tested in the cone calorimeter as three different experimental setups; dry, damp and inside a rust protection bag. Two full-scale experiments were also carried out where Pyrobubbles and rockwool were tested as packing material. In addition, a bow tie was created regarding the handling of packing material and an investigation of the ergonomics was conducted. The rust protection bag that is currently used at Scania to facilitate the packaging of Pyrobubbles contributes to unwanted heat release. The lowest heat release and best insulation capacity were measured for the sand. However, the sand is unmanageable to work with as it has a high density and contains carcinogenic particles. Rockwool is considered a good alternative to Pyrobubbles, which partly facilitates the work situation for employees and is also more accessible than Pyrobubbles. In order for rockwool to be accepted as a packing material, a certification of packing material and safety box must be done together, which applies to all new solutions. Keywords: Pyrobubbles, Lithium-ion battery, battery safety, ADR-S
72

Developing a Life Cycle Assessment model for an electric motorcycle

Kumar, Avinash January 2022 (has links)
Transport is one of the most carbon-intensive sectors in the world today. With increasing global population and economy, the share of emissions is expected to rise. Electric vehicle is one of promising technology that helps address this challenge. The electric vehicle segments of companies have broadened, and their sales have increased in the past decade. The electric motorcycle sector is growing fast, with the development of improved technology on electric powertrains, increased ranges, charging speeds and infrastructure. Parallel to the sales of these vehicles, the electric battery sector is advancing rapidly, thereby lowering the environmental impacts of these vehicles. The competitive adventure sport sector also benefits from using electric powertrains by taking advantage of their power-to-weight ratio and instant torque. The benefits of using electric vehicles can be seen during the use phase with zero tailpipe emissions and clean, silent riding. But with the expansion of the electric motorcycle sector rolling out new technologies and models, there are uncertainties as to whether the overall lifecycle of the vehicles have reduced impacts on the environment. To make improvements and to find the most sustainable models or solutions, it is important to analyse the impacts of the electric bikes on the environment.A case study has been performed at CAKE 0 Emission AB, in Stockholm, Sweden for the purpose of evaluating potential environmental impacts of KALK OR, an off-road electric two wheeler. This is achieved by carrying out a stand-alone assessment of KALK OR, to identify potential environmental hotspots. The study investigated the potential of manufacturing the motorcycle fossil-free. Attributional life cycle assessment was employed as a methodology with an explicit focus on nine impact categories at midpoint level. The results of the study indicated Suspensions, Frame, and battery to be the highest contributor of environmental impact. The common among them is one material, Aluminium. Battery on the other hand contributes highly on mineral resource scarcity, 26%. Other aspects and assumptions are also analyzed further using a sensitivity analysis, which shows the scope for decreasing KALK OR’s environmental footprint. Using this findings, three companies were selected to help reduce the environmental impact and their emission reduction potential was evaluated. It was found that using recycled aluminium could significantly reduce the global warming impact by 15% and the overall reduction from the Cleanest dirt bike ever project at the time of study could be 29.06%. Based on the results, it is recommended to use recycled aluminium. Additionally, from the various transport scenarios, it is recommended to avoid flight as that could lead to massive environmental impact. / Transportsektorn är idag en av världens mest utsläppstyngda branscher, med förväntad ökning av utsläppen i takt med växande befolkning. Elektrifiering av fordon ses som en av lösningarna för att hantera branschens problem. Det senaste decenniet har utbudet av elektriska fordon breddats och företag inom segmentet har sett stigande försäljningssiffror. Marknaden för elektriska motorcyklar växer snabbt, i takt med att både infrastruktur och den tekniska utvecklingen av elektriska drivlinor förbättras, med längre räckvidd och snabbare uppladdning som resultat. Även utvecklingen av batterier avancerar i raketfart, med möjlighet att minska klimatavtrycket för elfordon som kategori. Äventyrssport är ännu ett område där elektriska drivlinor kan konkurrera med sina fördelar genom fördelaktig effekt till-vikt förhållande och snabba vridmoment, utöver tyst och utsläppsfri körning i naturen. Trots de uppenbara fördelarna under körning råder det osäkerhet kring de elektriska elmotorcyklarnas miljöpåverkan ur ett livscykelperspektiv. För att styra utvecklingen av miljövänliga elmotorcyklar åt rätt håll är det helt centralt att analysera fordonets miljöpåverkan under hela livscykeln. I syfte att utvärdera miljöpåverkan under hela livscykeln för den elektriska off-road motorcykeln Kalk OR, har en studie genomförts hos CAKE 0 emission AB i Stockholm, Sverige. Studien har genomförts med utförandet av en fristående livscykelanalys på modellen Kalk OR, med målet att identifiera potentiell negativ miljöpåverkan, under samtliga faser av motorcykelns livscykel. Fallstudien undersökte möjligheterna för helt eliminera koldioxidutsläppen under produktionsfasen.En attributiv livscykelanalys utfördes med särskilt fokus på nio karakteriseringsfaktorer i mittpunkt. Resultatet indikerade att ram, stötdämpare och batteri var de delar med störst negativt avtryck på miljön. En gemensam nämnare för dessa delar är materialet aluminium. Batteri bidrar även till avtryck på knappa fossila resursers 26%. Fler aspekter och antaganden analyserades med hjälp av en känslighetsanalys för att påvisa möjligheterna för att minska fotavtrycket på miljön för modellen Kalk OR. Baserat på livscykelanalysen valdes tre leverantörer ut med potential att reducera fotavtrycket för Kalk OR. Företagens potential och lösningar utvärderades med insikten att återvunnen aluminium kan reducera Kalk OR:s bidrag till den globala uppvärmningen med 15%. Den totala reduceringen av koldioxidutsläpp för the Cleanest Dirt Bike Ever vid tiden för studien uppskattades till 29.06%.
73

FABRICATION AND EVALUATION ON ELECTROCHEMICAL PERFORMANCE OF SOLID POLYMER ELECTROLYTE MEMBREANE FOR LITHIUM-ION BATTERY

Ren, tianli, ren January 2017 (has links)
No description available.
74

Physical and electrochemical investigation of various dinitrile plasticizers in highly conductive polymer electrolyte membranes for lithium ion battery application

Feng, Chenrun January 2017 (has links)
No description available.
75

CURRENT OSCILLATIONS DURING COPPER ELECTRODISSOLUTION IN LITHIUM ION BATTERY AND ACIDIC CHLORIDE ELECTROLYTES

Cui, Qingzhou 20 December 2006 (has links)
No description available.
76

LITHIUM MAS NMR STUDIES OF LITHIUM ION ENVIRONMENT AND ION DYNAMIC PROCESS IN LITHIUM IRON AND MAGNESIUM PYROPHOSPHATE AS NEW SERIES OF CATHODE MATERIALS FOR LITHIUM ION BATTERIES

He, Xuan 04 1900 (has links)
<p>Lithium-ion batteries provide a more cost-effective and non-toxic source of reusable energy compare to other energy sources. Several research studies have lead to production of some more promising cathode components for lithium ion batteries. Recently, a new series of pyrophosphate-based composition Li<sub>2</sub>FeP<sub>2</sub>O<sub>7</sub> and Li<sub>2</sub>MnP<sub>2</sub>O<sub>7</sub> has been reported as cathode materials. They have shown a 3D framework structure and the two Lithium-ions in the three-dimensional tunnel structure make it possible that more than one lithium ion be extracted during cycling. Lithium solid state nuclear magnetic resonance (NMR) is an effective technique to study this cathode material, not only for analyzing local structure, but also for investigation of the microscopic processes that take place in the battery.</p> <p>In this work, Li<sub>2</sub>FeP<sub>2</sub>O<sub>7</sub> and Li<sub>2</sub>MnP<sub>2</sub>O<sub>7</sub> have been synthesized. The lithium environment of these materials is studied using 1D <sup>6,7</sup>Li NMR. Assignment of Li<sub>2</sub>MnP<sub>2</sub>O<sub>7</sub> spectrum has been made based on Fermi-contact interaction and crystal structure. Both variable temperature experiment and 1D selective inversion NMR are used to establish Li-ion pathways as well as Li hopping rates for Li<sub>2</sub>MnP<sub>2</sub>O<sub>7</sub>. Also, <sup>7</sup>Li MAS NMR measurements are used to characterize Li environments in LixFeP<sub>2</sub>O<sub>7 </sub>after being electrochemically cycled to different points, and preliminary results regard to changes to ion mobility in LixFeP<sub>2</sub>O<sub>7 </sub>at different electrochemical cycled points are presents here, solid-solution (de)lithetiation process is confirmed for this material.</p> / Master of Science (MSc)
77

Printable 3D MoS2 Architected Foam with Multiscale Structural Hierarchies for High-rate, High-capacity and High-mass-loading Energy Storage

Wei, Xuan 01 August 2021 (has links)
Materials with three-dimensional (3D) hierarchical architectures exhibit attractive mechanical, energy conversion and thermal radiative cooling properties not found in their bulk counterparts. However, implementation of hierarchically structured 3D transition metal dichalcogenides (TMDs) is widely deemed not possible, by the lack of manufacturing solutions that overcome the hierarchy, quality, and scalability dilemma. Here we report dewetting-driven destabilization (DDD) process that enables simple, template-free, high throughput printing of 3D architected MoS2 Foam with hierarchy spanning seven orders of magnitude — from angstroms to centimeters. Although extremely simple, our manufacturing process combines electrohydrodynamic printing with dewetting-induced-patterning. This technique can be applied to a range of dissimilar twodimensional (2D) layered materials, including Ti3C2Tx MXene and reduced graphene oxide (rGO). The deposited MoS2 Foam achieves amplification of resilience and conductivity. It constructs hierarchically porous and spatially interconnected networks for both ions and electrons transfer. We further demonstrate the 3D MoS2 architected foam as high-performance anodes with an otherwise unachievable combination of a 99% battery yield, a dynamic recovery (up to 85%) to withstand excessive volume expansion, a strain-induced reduction in diffusion barrier (0.2 eV), and improved electron transport abilities across the entire structure. The result is the high Li-ion charge storage capacity with robust cycling stability at a bulk scale (~3.5 mg/cm2) and under a high current density (10,000 mA/g). The outstanding electrochemical performance arises from the architected structure-induced pseudocapacitive energy storage mechanism based on the redox reaction of Mo, rather than the traditional conversion reaction. Notably, the performance achieved is on par with or surpasses state-of-the-art anodes made of black phosphorus composites, Si-graphene and mesoporous graphene particle anodes, while the technique offers an evaporation-like simplicity for industrial scalability. This work is foundational, and the developed DDD process opens a new sight to manufacture structurally robust, multifunctional hierarchical structures from 2D materials. Given the high adjustability of synthesis conditions and a wide variety of 2D materials, we anticipate previously unattainable possibilities in the energy storage, flexible electronics, catalysis, separation and drug delivery.
78

Fading phenomena in li-rich layered oxide material for lithium-ion batteries

Kim, Taehoon January 2015 (has links)
Lithium-rich layered transition metal oxide cathode, represented as the chemical formula of xLi<sub>2</sub>MnO<sub>3</sub> &middot; (1 - x)LiMO<sub>2</sub>(M = Mn, Ni, Co) , retains immense interest as one of the most promising candidates for energy storage system ranging from mobile devices to electric vehicle applications (EV/HEV/PHEV). This battery type benefits from superior theoretical capacity (&gt;250 mAhg<sup>-1</sup>), high chemical potential (&gt;4.6 V vs Li<sup>0</sup>), good thermal stability, high discharge capacity and lower cost compared with conventional cathodes (e.g. LiCoO<sub>2</sub>, Li(Ni<sub>1/3</sub>Mn<sub>1/3</sub>Co<sub>1/3</sub>)O<sub>2</sub> cathodes). However, there remain major barriers which still need to be improved in order to achieve a successful commercialization for large-scale devices or electric vehicle applications. The irreversible capacity loss of 40-100 mAhg<sup>-1</sup> during the initial electrochemical cycle and the battery fading phenomena (capacity fading/voltage decay) on further cycles are the major problems which have emerged. The Li<sup>+</sup> ion extraction accompanied by oxygen release from the active material in the form of oxide known as lithia (Li<sub>2</sub>O) along with the transition metal migration has been suggested as the dominant processes underlying the capacity fading mechanism. Those processes, in turn, cause a phase transition from a layered structure into a spinel within the electrode material. The interplay of the local atomic environments between Li<sub>2</sub>MnO<sub>3</sub> (monoclinic, C2/m) and LiMO<sub>2</sub> (trigonal/hexagonal, R3m) holds the key to developing better cathodes with enhanced stability. In the present thesis, an in operando XAS study using a specially-designed cell of the graphene- coated Li(Li<sub>0.2</sub>Mn<sub>0.54</sub>Ni<sub>0.13</sub>Co<sub>0.13</sub>)O<sub>2</sub> cathode is employed to examine the chemical, electronic, and structural states of the transition metals (Mn, Co, and Ni) during electrochemical cycle(s). Precise oxidation states for the transition metals is evaluated by the combined analyses from the XANES and SQUID measurements. The K-edge XANES spectral shift is quantified to investigate the contribution to the charge compensation mechanism by the oxidation change. Absorption features in K-edge XANES are identified. These features describe the electronic state of the individual atoms in the cathode composite, as well as the local distortion from the octahedral structure of MO<sub>6</sub>. The Fourier transform of EXAFS offers a satisfactory description of the local structure changes with the connection to the cation arrangement. The description is generally involved with the peak amplitude, position, shape changes (trend), and coordination numbers in the real space. Hence, similarities or discrepancies in the local atomic environments could be compared at different state of charge. Major structural parameters are deduced from the EXAFS fitting process. These parameters can be used to distinguish different atomic environments upon voltage bias levels or investigate the appearance of the Jahn-Teller effect. A new approach to understand the atomic environment upon charge-discharge is demonstrated, namely, a Continuous Cauchy Wavelet Transform (CCWT) which enables the visualization of the EXAFS spectra in three dimensions by decomposing the k-space and R-space (uncorrected for phase shift) signals. The wavelet transform analysis provides possible evidence of the precursor that leads to the spinel phase transition in this battery system.
79

Molecular precursor derived SiBCN/CNT and SiOC/CNT composite nanowires for energy based applications

Bhandavat, Romil January 1900 (has links)
Doctor of Philosophy / Department of Mechanical and Nuclear Engineering / Gurpreet Singh / Molecular precursor derived ceramics (also known as polymer-derived ceramics or PDCs) are high temperature glasses that have been studied for applications involving operation at elevated temperatures. Prepared from controlled thermal degradation of liquid-phase organosilicon precursors, these ceramics offer remarkable engineering properties such as resistance to crystallization up to 1400 °C, semiconductor behavior at high temperatures and intense photoluminescence. These properties are a direct result of their covalent bonded amorphous network and free (-sp2) carbon along with mixed Si/B/C/N/O bonds, which otherwise can not be obtained through conventional ceramic processing techniques. This thesis demonstrates synthesis of a unique core/shell type nanowire structure involving either siliconboroncarbonitride (SiBCN) or siliconoxycarbide (SiOC) as the shell with carbon nanotube (CNT) acting as the core. This was made possible by liquid phase functionalization of CNT surfaces with respective polymeric precursor (e.g., home-made boron-modified polyureamethylvinylsilazane for SiBCN/CNT and commercially obtained polysiloxane for SiOC/CNT), followed by controlled pyrolysis in inert conditions. This unique architecture has several benefits such as high temperature oxidation resistance (provided by the ceramic shell), improved electrical conductivity and mechanical toughness (attributed to the CNT core) that allowed us to explore its use in energy conversion and storage devices. The first application involved use of SiBCN/CNT composite as a high temperature radiation absorbant material for laser thermal calorimeter. SiBCN/CNT spray coatings on copper substrate were exposed to high energy laser beams (continuous wave at 10.6 μm, 2.5 kW CO2 laser, 10 seconds) and resulting change in its microstructure was studied ex-situ. With the aid of multiple techniques we ascertained the thermal damage resistance to be 15 kW/cm2 with optical absorbance exceeding 97 %. This represents one order of magnitude improvement over bare CNTs (1.4 kW/cm2) coatings and two orders of magnitude over the conventional carbon paint (0.1 kW/cm2) currently in use. The second application involved use of SiBCN/CNT and SiOC/CNT composite coatings as energy storage (anode) material in a Li-ion rechargeable battery. Anode coatings (~1mg/cm2) prepared using SiBCN/CNT synthesized at 1100 °C exhibited high reversible (useable) capacity of 412 mAh/g even after 30 cycles. Further improvement in reversible capacity was obtained for SiOC/CNT coatings with 686 mAh/g at 40 cycles and approximately 99.6 % cyclic efficiency. Further, post cycling imaging of dissembled cells indicated good mechanical stability of these anodes and formation of a stable passivating layer necessary for long term cycling of the cell. This improved performance was collectively attributed to the amorphous ceramic shell that offered Li storage sites and the CNT core that provided the required mechanical strength against volume changes associated with repeated Li-cycling. This novel approach for synthesis of PDC nanocomposites and its application based testing offers a starting point to carry out further research with a variety of PDC chemistries at both fundamental and applied levels.
80

Étude des interfaces électrodes/électrolyte à base de liquides ioniques pour batterie lithium-ion / Investigation of the interface electrode/ionic liquid based electrolyte for lithium ion battery

Bolimowska, Ewelina 28 June 2016 (has links)
Dans les batteries ion lithium, la présence d’électrolytes organiques volatiles et inflammables engendre des problèmes récurrents de sécurité. Une possible solution consiste à les remplacer par des sels fondus liquides à température ambiante, les liquides ioniques (LI), présentant une tension de vapeur négligeable et sont considérés comme flamme retardant. Leur utilisation avec des électrodes carbone (les plus usitées dans les batteries commerciales) nécessitent la présence d’un additif pour améliorer les performances des batteries.Le but de cette thèse était de déterminer le rôle de cet additif par des méthodes analytiques et de la modélisation. Tout d’abord, l’impact de cet additif sur la solvatation et la diffusion des sels de lithium a été étudié par RMN 2-D [NOE et HOESY {1H-7Li}, {1H-19F}, et la sphère de coordination du cation lithium a été simulée par dynamique moléculaire. Puis des études électrochimiques ont été développées notamment le cyclage galvanostatique à potentiel sélectionné et le cyclage voltamétrique afin de déterminer la capacité de la batterie et d’étudier les étapes d‘insertion du cation lithium au cours de la première étape de réduction. Cette étape a également été analysée par impédance électrochimique. En complément, une analyse par XPS (spectrométrie photoélectronique X) sur les électrodes post-mortem de piles arrêtées aux potentiels déterminés par impédance, a permis de caractériser les composés chimiques formés à la surface des électrodes au cours de la première réduction, mais également après plusieurs cycles de charge/décharge / In lithium ion batteries, the commercial organic electrolytes induce difficulties in the manufacturing and the use of the battery (volatile and flammable components). There are active research to eliminate these safety problems, one of the approach is the replacement of conventional battery electrolytes with room temperature ionic liquids (RTILs), which exhibit negligible vapor pressure, low flammability, high flash point. The use of ILs based electrolytes for carbon based electrodes requires presence of organic additive for improving the cyclic performance. The aim of this thesis was to determine the exact role of the organic additive through experimental and computer simulation methodologies. Its impact onto the solvation and transportation of lithium cation was investigated through {1H-7Li}, {1H-19F} NOE correlations (HOESY), and pulsed field gradient spin-echo (PGSE) NMR experiences and Molecular Dynamic simulation. The electrochemical studies were developed such as electrochemical window, galvanostatic cycling with potential limitation and cycling voltammetry showing the obtained capacity of the cell and [Li+] insertion stages during the first reduction step. Moreover, the electrochemical impedance spectroscopy (EIS) during the first reduction process, and XPS analysis of post mortem Gr electrodes stopped at chosen potential during the first reduction process, as well as, after the several charge/discharge cycles were used

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