• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 157
  • 35
  • 13
  • 7
  • 5
  • 4
  • 2
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • Tagged with
  • 288
  • 288
  • 288
  • 74
  • 70
  • 59
  • 50
  • 44
  • 38
  • 31
  • 30
  • 30
  • 29
  • 29
  • 27
  • 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.
261

Improving the Electrochemical Performance and Safety of Lithium-Ion Batteries Via Cathode Surface Engineering

Kum, Lenin Wung 07 August 2023 (has links)
No description available.
262

Fuzzy-Rule-Based Failure Detection and Early Warning System for Lithium-ion Battery

Wu, Meng 05 September 2013 (has links)
Indiana University-Purdue University Indianapolis (IUPUI) / Lithium-ion battery is one kind of rechargeable battery, and also renewable, sustainable and portable. With the merits of high density, slow loss of charge when spare and no memory effect, lithium-ion battery is widely used in portable electronics and hybrid vehicles. Apart from its advantages, safety is a major concern for Lithium-ion batteries due to devastating incidents with laptop and cell phone batteries. Overcharge and over-discharge are two of the most common electrical abuses a lithium-ion battery suffers. In this thesis, a fuzzy-rule-based system is proposed to detect the over-charge and over-discharge failure in early time. The preliminary results for the failure signatures of overcharged and over-discharged lithium-ion are listed based on the experimental results under both room temperature and high temperature. A fuzzy-rule-based model utilizing these failure signatures is developed and validated. For over-charge case, the abnormal increase of the surface temperature and decrease of the voltage are captured. While for over discharge case, unusual temperature increase during overcharge phases and abnormal current decrease during overcharge phases are obtained. The inference engine for fuzzy-rule-based system is designed based on these failure signatures. An early warning signal will be given by this algorithm before the failure occurs. This failure detection and early warning system is verified to be effective through experimental validation. In the validation test, the proposed methods are successfully implemented in a real-time system for failure detection and early warning. The result of validation is compatible with the design expectation. Finally an accurate failure detection and early warning system is built and tested successfully.
263

Dynamic Modeling and Thermal Characterization of Lithium-Ion Batteries

Alsharif, Khaled I. 01 May 2023 (has links)
No description available.
264

GRAPHENE BASED ANODE MATERIALS FOR LITHIUM-ION BATTERIES

Cheekati, Sree Lakshmi 20 April 2011 (has links)
No description available.
265

Data Driven Microstructural Design of Porous Electrodes

Abhas Deva (11845406) 16 December 2021 (has links)
<div> Porous lithium ion battery (LIB) electrodes are comprised of electrochemically active material particles that store lithium and a surrounding conductive binder, liquid electrolyte, carbon black mixture that facilitates ionic and electronic transport. Typically, lithium diffusivity is several orders of magnitude smaller in the active material as compared to the surrounding electrolyte, making the electrode microstructure a governing factor in determining the balance between its lithium storage capacity and transport rate. Here, the effects of microstructure on the performance of LIBs are systematically analyzed at three length scales - the single particle length scale, the spatially resolved multiple particle length scale, and the porous electrode layer (homogenized) length scale. At the single particle length scale, a thermodynamically consistent variational framework is presented to examine the effects of crystallographic anisotropy, crystallographic texture, grain size, and grain morphology on the LiNi<sub>1/3</sub>Mn<sub>1/3</sub>Co<sub>1/3</sub>O<sub>2</sub> (NMC111) chemistry. The theory was extended to the spatially resolved multiple particle length scale and the porous electrode layer length scale to explain the microstructural origin of experimentally observed instances of apparent phase separation in NMC111. At the electrode length scale, a data driven framework is presented to evaluate the electrochemical performance of a wide range of particle morphologies and battery architectures. Specifically, microstructural characteristics of 53 356 microstructures are assessed, and strategies to optimize electrode design parameters such as active particle morphology, spatial orientation, electrode porosity, and cell thickness are presented.</div><p></p>
266

Study of the Potential of Electrified Powertrains with Dual-Fuel Combustion to Achieve the 2025 Emissions Targets in Heavy-Duty Applications

Martínez Boggio, Santiago Daniel 24 October 2022 (has links)
[ES] El transporte de personas, así como de carga ha evolucionado y crecido tremendamente en los últimos años. El desarrollo tecnológico debió ser adaptado a las diferentes medidas gubernamentales en términos de control de emisiones contaminantes. Desde el acuerdo de Paris en 2015 para mantener el crecimiento de la temperatura global por debajo de 1.5oC, se han impuesto también límites para las emisiones de CO2 por parte de vehículos de carretera. Para el sector del transporte pesado, se han impuesto límites de flota de 15% para 2025 y 30% para 2030 de reducción del CO2 con respecto a 2019. Por lo tanto, esta doble restricción de muy bajos niveles de emisiones contaminantes, así como de gases de efecto invernadero hacen que el sector del transporte este ante un gran desafío tecnológico. En 2022, el transporte de carga tiene un 99% de vehículos propulsados a motor de combustión interna con Diesel como combustible y sin ningún tipo de ayuda eléctrica en el sistema de propulsión. Los límites de emisiones contaminantes como Euro 6 son alcanzados con complejos sistemas de postratamiento que además agregan el consumo de Urea. Trabajos previos en la bibliografía, así como sistemas prototipo han demostrado que es posible alcanzar los objetivos de emisiones contaminantes con métodos avanzados de control de la combustión y así disminuyendo la complejidad del post tratamiento en la salida de gases. Con mayor éxito, el concepto de Reactivity Controlled Combustion Ignition puede alcanzar valores por debajo de Euro 6 con eficiencia similar a la combustión de Diesel. Sin embargo, no soluciona los problemas de emisiones de CO2. Por otro lado, en vehículos de pasajeros fue demostrado con suceso la aplicación de motores eléctricos en el sistema de propulsión para mejorar la eficiencia global del vehículo. El caso extremo son los vehículos puramente electicos donde se alcanza eficiencias por arriba del 70% contra 35% de los vehículos no electrificados. Sin embargo, limitaciones de autonomía, tiempo de carga y la no clara reducción global de la contaminación debido a las emisiones de la energía de la red eléctrica y la contaminación de las baterías de ion-litio hacen que este sistema de propulsión este bajo discusión. Para los vehículos con algún grado de electrificación, las emisiones de gases contaminantes siguen siendo un problema como para el caso no electrificado. Por lo tanto, esta tesis doctoral aborda el problema de emisiones contaminantes, así como de CO2 combinado modos avanzados de combustión con sistemas de propulsión electrificado. La aplicación de estas tecnologías se centra en el sector del transporte de carretera pesado. En particular, un camión de 18 toneladas de carga máxima que originalmente en 2022 equipa un motor seis cilindros de 8 litros con combustión convencional Diesel. El presente trabajo utiliza herramientas experimentales como son medidas en banco motor, así como en carretera para alimentar y validar modelos numéricos de motor, sistema de postratamiento, así como de vehículo. Este último es el punto central del trabajo ya que permite abordar sistemas como el mild hybrid, full hybrid y plug-in hybrid. Calibración de motor experimental dedicada a sistemas de propulsión hibrido es presentada con combustibles sintéticos y/o para llegar a los límites de Euro 7. / [CA] El transport de persones, així com de càrrega ha evolucionat i crescut tremendament en els últims anys. El desenvolupament tecnològic degué ser adaptat a les diferents mesures governamentals en termes de control d'emissions contaminants. Des de l'acord de Paris en 2015 per a mantindre el creixement de la temperatura global per davall de 1.5oC, s'han imposat també límits per a les emissions de CO¿ per part de vehicles de carretera. Per al sector del transport pesat, s'han imposat limites de flota de 15% per a 2025 i 30% per a 2030 de reducció del CO¿ respecte a 2019. Per tant, aquesta doble restricció de molt baixos nivells d'emissions contaminants, així com de gasos d'efecte d'hivernacle fan que el sector del transport aquest davant un gran desafiament tecnològic. En 2022, el transport de càrrega té un 99% de vehicles propulsats a motor de combustió interna amb Dièsel com a combustible i sense cap mena d'ajuda elèctrica en el sistema de propulsió. Els limites d'emissions contaminants com a Euro 6 són aconseguits amb complexos sistemes de posttractament que a més agreguen el consum d'Urea. Treballs previs en la bibliografia, així com sistemes prototip han demostrat que és possible aconseguir els objectius d'emissions contaminants amb mètodes avançats de control de la combustió i així disminuint la complexitat del post tractament en l'eixida de gasos. Amb major èxit, el concepte de Reactivity Controlled Combustion Ignition pot aconseguir valors per davall d'Euro 6 amb eficiència similar a la combustió de Dièsel. No obstant això, no soluciona els problemes d'emissions de CO¿. D'altra banda, en vehicles de passatgers va ser demostrat amb succés l'aplicació de motors elèctrics en el sistema de propulsió per a millorar l'eficiència global del vehicle. El cas extrem són els vehicles purament electicos on s'aconsegueix eficiències per dalt del 70% contra 35% dels vehicles no electrificats. No obstant això, limitacions d'autonomia, temps de càrrega i la no clara reducció global de la contaminació a causa de les emissions de l'energia de la xarxa elèctrica i la contaminació de les bateries d'ió-liti fan que aquest sistema de propulsió aquest baix discussió. Per als vehicles amb algun grau d'electrificació, les emissions de gasos contaminants continuen sent un problema com per al cas no electrificat. Per tant, aquesta tesi doctoral aborda el problema d'emissions contaminants, així com de CO¿ combinat maneres avançades de combustió amb sistemes de propulsió electrificat. L'aplicació d'aquestes tecnologies se centra en el sector del transport de carretera pesat. En particular, un camió de 18 tones de càrrega màxima que originalment en 2022 equipa un motor sis cilindres de 8 litres amb combustió convencional Dièsel. El present treball utilitza eines experimentals com són mesures en banc motor, així com en carretera per a alimentar i validar models numèrics de motor, sistema de posttractament, així com de vehicle. Est ultime és el punt central del treball ja que permet abordar sistemes com el mild hybrid, full *hybrid i plug-in hybrid. Calibratge de motor experimental dedicada a sistemes de propulsió hibride és presentada amb combustibles sintètics i/o per a arribar als límits d'Euro 7. / [EN] The transport of people, as well as cargo, has evolved and grown tremendously over the recent years. Technological development had to be adapted to the different government measures for controlling polluting emissions. Since the Paris agreement in 2015 limits have also been imposed on the CO2 emissions from road vehicles to keep global temperature growth below 1.5oC. For the heavy transport sector, fleet limits of 15% for 2025 and 30% for 2030 CO2 reduction have been introduced with respect to the limits of 2019. Therefore, the current restriction of very low levels of polluting emissions, as well as greenhouse gases, makes the transport sector face a great technological challenge. In 2021, 99% of freight transport was powered by an internal combustion engine with Diesel as fuel and without any type of electrical assistance in the propulsion system. Moreover, polluting emission limits such as the Euro 6 are achieved with complex post-treatment systems that also add to the consumption of Urea. Previous research and prototype systems have shown that it is possible to achieve polluting emission targets with advanced combustion control methods, thus reducing the complexity of post-treatment in the exhaust gas. With greater success, the concept of Reactivity Controlled Combustion Ignition can reach values below the Euro 6 with similar efficiency to Diesel combustion. Unfortunately, it does not solve the CO2 emission problems. On the other hand, in passenger vehicles, the application of electric motors in the propulsion system has been shown to successfully improve the overall efficiency of the vehicle. The extreme case is the purely electric vehicles, where efficiencies above 70% are achieved against 35% of the non-electrified vehicles. However, limitations of vehicle range, charging time, payload reduction and an unclear overall reduction in greenhouse emissions bring this propulsion system under discussion. For vehicles with some degree of electrification, polluting gas emissions continue to be a problem as for the non-electrified case. Therefore, this doctoral Thesis addresses the problem of polluting emissions and CO2 combined with advanced modes of combustion with electrified propulsion systems. The application of these technologies focuses on the heavy road transport sector. In particular, an 18-ton maximum load truck that originally was equipped with an 8-liter six-cylinder engine with conventional Diesel combustion. The present work uses experimental tools such as measurements on the engine bench as well as on the road to feed and validate numerical models of the engine, after-treatment system, and the vehicle. The latter is the central point of the work since it allows addressing systems such as mild hybrid, full hybrid, and plug-in hybrid. Experimental engine calibration dedicated to hybrid propulsion systems is presented with synthetic fuels in order to reach the limits of the Euro 7. / This Doctoral Thesis has been partially supported by the Universitat Politècnica de València through the predoctoral contract of the author (Subprograma 2), which is included within the framework of Programa de Apoyo para la Investigación y Desarrollo (PAID) / Martínez Boggio, SD. (2022). Study of the Potential of Electrified Powertrains with Dual-Fuel Combustion to Achieve the 2025 Emissions Targets in Heavy-Duty Applications [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/188835
267

Surface modification of Li(Ni0.6Mn0.2Co0.2)O2 by plasma deposition for compatibility with aqueous processing

Tomassi, Erica 05 1900 (has links)
Les batteries lithium-ion dépendent de l’utilisation d’électrodes composites positives, traditionnellement préparées avec des liants fluorés tels que le polyfluorure de vinylidène (PVDF). Ceux-ci sont souvent dissouts ou dispersés dans des solvants toxiques et inflammables. Les interdictions récentes des substances per- et polyfluoroalkyles (PFAS), qualifiées de polluants éternels, imposent le développement d'alternatives durables pour atténuer les dommages environnementaux supplémentaires. La carboxyméthylcellulose (CMC) est une alternative prometteuse aux liants à base de PFAS car elle est biosourcée, biodégradable et soluble dans l'eau. Cependant, le processus d'utilisation d'un liant aqueux durable de CMC avec un matériau actif sensible à l'humidité, Li(Ni0.6Mn0.2Co0.2)O2, NMC622, dans une électrode composite positive présente un grand défi. Une avancée notable est l'application d'un revêtement protecteur qui peut être appliqué directement sur la surface des particules du matériau actif à l'aide d'un jet de plasma à pression atmosphérique (APPJ). Dans cette étude, l'APPJ a été utilisé pour déposer un revêtement organosilicié sur les particules de NMC622. Les particules de NMC enrobées ont subi des tests chimiques et électrochimiques rigoureux pour déterminer leur composition chimique et leur microstructure modifiée. Bien que ces résultats soient prometteurs, la performance électrochimique, mesurée par la capacité spécifique, la densité énergétique, l’efficacité coulombique, la stabilité cyclique, la durée de vie et la stabilité mécanique, n’est pas optimale, possiblement en raison de la dégradation préalable du matériau actif et d’une couverture inhomogène. Les particules enrobées ont connu un degré de protection contre l'exposition à l'humidité, aux électrolytes courants et aux environnements aqueux. La présence du revêtement s'est avérée préserver la microstructure des particules sans avoir d'impact significatif sur les propriétés électrochimiques du matériau, telles que la capacité spécifique et l’efficacité coulombique. / Lithium-ion batteries rely on the use of positive composite electrodes, which are traditionally prepared using fluorinated binders such as polyvinylidene fluoride (PVDF). These are often dissolved or dispersed in toxic and flammable solvents. Recent bans on ‟forever chemicals” per- and polyfluoroalkyl substances (PFAS) impose the development of sustainable alternatives to mitigate further environmental damage. Carboxymethyl cellulose (CMC) is a promising alternative to PFAS-based binders as it is bio-sourced, bio-degradable, and water-soluble. However, the process of using a sustainable CMC aqueous binder with a humidity sensitive active material, Li(Ni0.6Mn0.2Co0.2)O2, NMC622, in a positive composite electrode is challenging. One notable advancement is the application of a protective coating that can be applied directly on the active material particles surface using atmospheric pressure plasma jet (APPJ). In this study, the APPJ was used to deposit an organosilicon coating onto NMC622 particles. The coated NMC particles underwent rigorous chemical and electrochemical testing to determine the chemical composition, and microstructure of the modified particles. Despite promising indications, the electrochemical performance, measured by specific capacity, energy density, coulombic efficiency, cycling stability, lifetime and mechanical stability, is not optimal due possibly to the priori degraded active material and inhomogeneous coverage. The coated particles experienced a degree of protection from exposure to humidity, common electrolytes, and aqueous environments. The presence of the coating was found to preserve particle microstructure without having a significant impact on the electrochemical properties of the material, such as specific capacity and coulombic efficiency.
268

Improving a Circular Electric Vehicle Battery Value Chain : A Case Study of Sustainable Waste Management of Lithium-Ion Batteries

Sithoumphalath, Sithiphone January 2024 (has links)
This master’s thesis aims to improve the circularity of the electric vehicle (EV) battery value chain, specifically focusing on sustainable waste management of Lithium-Ion Batteries (LIBs) in Europe, particularly Sweden. The research objectives include evaluating and proposing actionable recommendations to enhance circularity, addressing environmental impacts, and supporting the industry’s transition towards a sustainable business model aligned with the new European Union (EU) Battery Regulation, which aims to enhance recycling rates, reduce environmental impact, and secure the recovery of valuable materials. The key research questions addressed are: (1) What initiatives, technologies, or best practices are currently being developed to support circularity and sustainable waste management in the EV battery value chain? (2) How can the circularity of the EV battery value chain be enhanced, particularly in sustainable waste management for LIBs? (3) What environmental impacts, socio-economic opportunities, and challenges exist in a circular value chain in the EV battery industry? The methodology employed a mixed-methods approach, including a literature review and case study, stakeholder interviews, SWOT analysis and life cycle assessment (LCA) using Minviro LCA software to quantify and compare the environmental impacts of state-of-the-art industrial LIB recycling methods. Key findings indicate that several initiatives and technologies are being developed to support circularity, including advanced recycling technologies and second-life applications for batteries. Enhancing circularity requires regulatory support, technological advancements, and stakeholder collaborative efforts. The findings highlight significant potential for extending the lifecycle of EV batteries through re-use, re-purposing, and recycling strategies. The analysis reveals that advancements in recycling technologies and supportive regulatory frameworks can substantially reduce the environmental impact and improve LIB supply chain sustainability. Notably, the LCA results highlight that mechanical and hydrometallurgical recycling processes offer more favourable environmental outcomes than pyrometallurgical methods. Thus, it shows potential for lower environmental impact on greenhouse gas (GHG) emissions and resource depletion, alongside socio-economic opportunities like job creation and economic growth. However, challenges such as technological barriers, economic feasibility, regulatory compliance, and EV battery value chain complexities remain, and these must be addressed. The conclusions drawn from the findings recommend that a combination of regulatory support, technological innovation, and stakeholder collaboration is essential for improving the circularity of the EV battery value chain. The study recommends advancements in recycling technologies, developing efficient testing and certification processes for second-life batteries, and establishing clear regulatory frameworks to facilitate circular economy practices. These measures are crucial for supporting the industry’s shift towards a more sustainable and circular model, ultimately contributing to the EU’s climate neutrality goals by 2050.
269

Synthèse et caractérisation d’oxydes lamellaires riches en lithium et en manganèse obtenus sous la forme de gradients de concentration pour les batteries Li-ion / Synthesis and characterization of lithium and manganese rich layered oxides obtained as concentration-gradients for Li-ion batteries

Pajot, Ségolène 16 December 2016 (has links)
Ce travail présente la mise en oeuvre d’un protocole de synthèse de gradients deconcentration dans les oxydes lamellaires riches en Li et en Mn. Le but a été dedévelopper la formation d’oxydes lamellaires riches en Li et Mn au coeur des agrégatssphériques du matériau actif et, en se rapprochant de la surface, d’enrichir lacomposition de l’oxyde lamellaire en Co et en Ni, afin de combiner une forte densitéd’énergie (apportée par le coeur du gradient) et une excellente stabilité thermique etstructurale (apportée par la surface du gradient). La synthèse a été réalisée en deuxétapes, une co-précipitation pour former un carbonate de métaux de transition suivied’une calcination à haute température pour obtenir le matériau actif lithié. L’influencede différents paramètres (pH, débit d’injection, taille du réacteur, composition, …) surla nature du carbonate à gradient de concentration ainsi formé a été étudiée. De lamême façon, le contrôle du ratio Li/M (ici M = Ni, Co, Mn), de la température et de ladurée de calcination s’est révélé important pour parvenir à maintenir le gradient deconcentration dans le matériau lithié. Le ratio Li/M est également déterminant pourcontrôler la nature des matériaux obtenus (lamellaire - spinelle ou lamellaire –lamellaire). Des caractérisations extrêmement pointues, et complexes à mettre enoeuvre, ont été menées afin d’obtenir des informations pertinentes sur la distributiondes phases au sein des agrégats (composition et structure), de la surface au coeur dugradient : différentes techniques de microscopie (EPMA, MEB-EDX et FIB-STEM) ontainsi été largement utilisées. Les matériaux les plus intéressants ont été étudiés enbatteries Lithium-ion avec une électrode de graphite à la négative, les performancesélectrochimiques et la stabilité thermique à l’état chargé de la batterie sont largementdiscutées par rapport à l’état de l’art et notamment au matériau de coeur riche en Li eten Mn. / This work describes in details the implementation of the synthesis protocol for theformation of Li- and Mn-rich layered oxides with concentration-gradients. The purposewas to develop the synthesis of Li- and Mn-rich layered oxides in the bulk of sphericalaggregates of active material and, moving to the surface, to enrich the layered oxides’composition with Co and Ni, in order to combine a high energy density (provided bythe bulk) and an excellent thermal and structural stability (provided by the surface).The synthesis was performed in two steps, a coprecipitation to form a transition metalcarbonate followed by a calcination at high temperature to obtain the lithiated activematerial. The influence of several parameters (pH, feeding rate, size of the reactor,composition …) on the nature of the carbonates formed with concentration-gradientswas studied. Similarly, the control of the Li/M ratio (with M = Ni, Co, Mn) and of thetemperature and duration of calcination was revealed to be important to maintain theconcentration-gradient in the lithiated materials. The Li/M ratio is also the keyparameter to control the nature of the materials obtained (layered - spinel or layered -layered). Advanced characterizations, complex to be implemented, were performed inorder to obtain in-depth information on the distribution of phases within the aggregates(composition and structure), from the bulk to the surface: complementary microscopytechniques (EPMA, SEM-EDS and FIB-STEM) were widely used. The most interestingmaterials were studied in Lithium-ion batteries with graphite at the negative electrode,their electrochemical performance and the thermal stability in the charged state of thebattery were compared to the state of art, and particularly to the bulk Li and Mn-richlayered oxide.
270

Resilient and Real-time Control for the Optimum Management of Hybrid Energy Storage Systems with Distributed Dynamic Demands

Lashway, Christopher R 26 October 2017 (has links)
A continuous increase in demands from the utility grid and traction applications have steered public attention toward the integration of energy storage (ES) and hybrid ES (HESS) solutions. Modern technologies are no longer limited to batteries, but can include supercapacitors (SC) and flywheel electromechanical ES well. However, insufficient control and algorithms to monitor these devices can result in a wide range of operational issues. A modern day control platform must have a deep understanding of the source. In this dissertation, specialized modular Energy Storage Management Controllers (ESMC) were developed to interface with a variety of ES devices. The EMSC provides the capability to individually monitor and control a wide range of different ES, enabling the extraction of an ES module within a series array to charge or conduct maintenance, while remaining storage can still function to serve a demand. Enhancements and testing of the ESMC are explored in not only interfacing of multiple ES and HESS, but also as a platform to improve management algorithms. There is an imperative need to provide a bridge between the depth of the electrochemical physics of the battery and the power engineering sector, a feat which was accomplished over the course of this work. First, the ESMC was tested on a lead acid battery array to verify its capabilities. Next, physics-based models of lead acid and lithium ion batteries lead to the improvement of both online battery management and established multiple metrics to assess their lifetime, or state of health. Three unique HESS were then tested and evaluated for different applications and purposes. First, a hybrid battery and SC HESS was designed and tested for shipboard power systems. Next, a lithium ion battery and SC HESS was utilized for an electric vehicle application, with the goal to reduce cycling on the battery. Finally, a lead acid battery and flywheel ES HESS was analyzed for how the inclusion of a battery can provide a dramatic improvement in the power quality versus flywheel ES alone.

Page generated in 0.0719 seconds