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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.
101

Fabrication of hierarchical hybrid nanostructured electrodes based on nanoparticles decorated carbon nanotubes for Li-Ion batteries / Fabrication d'électrodes nanostructurées hybrides hiérarchisées à base de nanotubes de carbone décorés par des nanoparticules pour les batteries Li-Ion

Ezzedine, Mariam 20 December 2017 (has links)
Cette thèse est consacrée à la fabrication ascendante (bottom-up) de matériaux nanostructurés hybrides hiérarchisés à base de nanotubes de carbone alignés verticalement (VACNTs) décorés par des nanoparticules (NPs). En fonction de leur utilisation comme cathode ou anode, des nanoparticules de soufre (S) ou silicium (Si) ont été déposées. En raison de leur structure unique et de leurs propriétés électroniques, les VACNTs agissent comme une matrice de support et un excellent collecteur de courant, améliorant ainsi les voies de transport électroniques et ioniques. La nanostructuration et le contact du S avec un matériau hôte conducteur améliore sa conductivité, tandis que la nanostructuration du Si permet d'accommoder plus facilement les variations de volume pendant les réactions électrochimiques. Dans la première partie de la thèse, nous avons synthétisé des VACNTs par une méthode de dépôt chimique en phase vapeur (HF-CVD) directement sur des fines feuilles commerciales d'aluminium et de cuivre sans aucun prétraitement des substrats. Dans la deuxième partie, nous avons décoré les parois latérales des VACNTs avec différents matériaux d'électrode, dont des nanoparticules de S et de Si. Nous avons également déposé et caractérisé des nanoparticules de nickel (Ni) sur les VACNTs en tant que matériaux alternatifs pour l'électrode positive. Aucun additif conducteur ou aucun liant polymère n'a été ajouté à la composition d'électrode. La décoration des nanotubes de carbone a été effectuée par deux méthodes différentes: méthode humide par électrodéposition et méthode sèche (par dépôt physique en phase vapeur (PVD) ou par CVD). Les structures hybrides obtenues ont été testées électrochimiquement séparément dans une pile bouton contre une contre-électrode de lithium. A notre connaissance, il s'agit de la première étude de l'évaporation du soufre sur les VACNTs et de la structure résultante (appelée ici S@VACNTs). Des essais préliminaires sur les cathodes nanostructurées obtenues (S@VACNTs revêtus d'alumine ou de polyaniline) ont montré qu'il est possible d'atteindre une capacité spécifique proche de la capacité théorique du soufre. La capacité surfacique de S@VACNTs, avec une masse de S de 0.76 mg cm-2, à un régime C/20 atteint une capacité de 1.15 mAh cm-2 au premier cycle. Pour les anodes nanostructurées au silicium (Si@VACNTs), avec une masse de Si de 4.11 mg cm-2, on montre une excellente capacité surfacique de 12.6 mAh cm-2, valeur la plus élevée pour les anodes à base de silicium nanostructurées obtenues jusqu'à présent. Dans la dernière partie de la thèse, les électrodes nanostructurées fabriquées ont été assemblées afin de réaliser la batterie complète (Li2S/Si) et sa performance électrochimique a été testée. Les capacités surfaciques obtenues pour les électrodes nanostructurées de S et de Si ouvrent la voie à la réalisation d'une LIB à haute densité d'énergie, entièrement nanostructurée, et démontrent le grand potentiel du concept proposé à base d'électrodes nanostructurées hybrides hiérarchisées. / This thesis is devoted to the bottom-up fabrication of hierarchical hybrid nanostructured materials based on active vertically aligned carbon nanotubes (VACNTs) decorated with nanoparticles (NPs). Owing to their unique structure and electronic properties, VACNTs act as a support matrix and an excellent current collector, and thus enhance the electronic and ionic transport pathways. The nanostructuration and the confinement of sulfur (S) in a conductive host material improve its conductivity, while the nanostructuration of silicon (Si) accommodates better the volume change during the electrochemical reactions. In the first part of the thesis, we have synthesized VACNTs by a hot filament chemical vapor deposition (HF-CVD) method directly over aluminum and copper commercial foils without any pretreatment of the substrates. In the second part, we have decorated the sidewalls and the surface of the VACNT carpets with various LIB's active electrode materials, including S and Si NPs. We have also deposited and characterized nickel (Ni) NPs on CNTs as alternative materials for the cathode electrode. No conductive additives or any polymer binder have been added to the electrode composition. The CNTs decoration has been done systematically through two different methods: wet method by electrodeposition and dry method by physical vapor deposition (PVD). The obtained hybrid structures have been electrochemically tested separately in a coin cell against a lithium counter-electrode. Regarding the S evaporationon VACNTs, and the S@VACNTs structure, these topics are investigated for the first time to the best of our knowledge.Preliminary tests on the obtained nanostructured cathodes (S@VACNTs coated with alumina or polyaniline) have shown that it is possible to attain a specific capacity close to S theoretical storage capacity. The surface capacity of S@VACNTs, with 0.76 mg cm-2 of S, at C/20 rate reaches 1.15 mAh cm-2 at the first cycle. For the nanostructured anodes Si@VACNTs, with 4.11 mg cm-2 of Si showed an excellent surface capacity of 12.6 mAh cm-2, the highest value for nanostructured silicon anodes obtained so far. In the last part of the thesis, the fabricated nanostructured electrodes have been assembled in a full battery (Li2S/Si) and its electrochemical performances experimentally tested. The high and well-balanced surface capacities obtained for S and Si nanostructured electrodes pave the way for realization of high energy density, all-nanostructured LIBs and demonstrate the large potentialities of the proposed hierarchical hybrid nanostructures' concept.
102

Development of x-ray spectroscopy coupling with resonant scattering -toward applications of practical materials- / 共鳴散乱を組み合わせたX線分光法の開発 -実用材料への応用に向けて-

Kawaguchi, Tomoya 23 March 2015 (has links)
京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第18981号 / 工博第4023号 / 新制||工||1619(附属図書館) / 31932 / 京都大学大学院工学研究科材料工学専攻 / (主査)教授 松原 英一郎, 教授 邑瀬 邦明, 教授 宇田 哲也 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DGAM
103

An Intelligent Battery Managment System For Electric And Hybrid Electric Aircraft

Hashemi, Seyed Reza 24 March 2021 (has links)
No description available.
104

Amphibia : Living on both sides

Nielsen, Elvira January 2023 (has links)
Mariestad municipality participated in a global competition to become Volvo’s site for a new lithium-ion battery factory. The competition was between eleven different countries and three different locations in Sweden. Aer declaring Mariestad and the site Korstorp as winners, extensive surveys of the site were initiated during which they did a rare find of the protected species the great crested newt. However, Volvo is still planning on going through with building the factory the way they planned, which implies asphalting an area of 140-150 ha and constructing a box like factory of one or two floors. The newts are now under great threat and will have to be moved in order to make room for the factory. Building battery factories is something we strive for on a global scale, but what happens when global sustainability opposes local? In the example of the battery factory in Mariestad Agenda 2030’s sustainable development goals biodiversity and economic growth seem to be in opposition to each other and here it becomes clear that the value of humans and non-humans are different. How are we to remedy the unequal distribution of power and how can we turn the conflict zone in Korstorp into a zone of diplomacy? The convention of the rights of the child became Swedish law in 2020 and here it is relevant taking a look at article 12, which says; “All children have the right to express their opinions, adults shall listen and consider the children’s opinions”. The children are our future and they have to live with our choices. Building in a sustainable manner implies listening to who will be affected. The society’s measurement of success needs to be altered from economic growth to one which everybody has the right to be part of. To reach that place we have to practice at an early age to think and act in a democratic manner. If children feel as if they have been heard they could come to appreciate democratic processes in which they trust their ability to alter the society and feel obligated towards it. Furthermore, the unlimited imagination of children and the fact that they are not yet indoctrinated in the routines and customs of our society might bring the innovation needed to create a new kind of factory in symbiosis with the local environment.
105

Strategies for enhancing the circularity of Lithium-ion Batteries.

Malik, Tanveer Ahmad January 2023 (has links)
Li-ion batteries have gained great popularity among researchers and practitioners as an environmentally friendly energy storage solution for more environmentally friendly electric vehicles (EVs). However, because of the increased demand for Li-ion battery-powered EVs, and some issues with battery design, legislation, collection and sorting, recycling, and material recovery, achieving sustainable mobility through the circularity of Li-ion batteries is a major challenge. This study aims to identify the challenges as well as develop strategies for enhancing the circularity of Li-ion batteries in Sweden. Following a systematic literature review, two primary research questions were investigated: 1) what are the current challenges and opportunities for the circular economy in lithium-ion battery end-of-life management? 2) how the circularity of LIBs in Sweden could be enhanced? This study employed PEST and SWOT analysis, as well as 11 interviews with industry experts and researchers are performed, to determine the strengths, weaknesses, opportunities, and threats in the circularity of lithium-ion batteries in Sweden. Following that, various strategies were developed to address the identified challenges and improve the circular economy of these batteries. Finally, the developed strategies are validated through expert interviews, and various recommendations are outlined. The study's findings are significant and can assist policymakers, investors, and industry professionals concerned with the circularity of lithium-ion batteries in developing appropriate decisions and better planning for the Swedish transportation sector.
106

Industrialization of Lithium-Ion Prismatic Battery Cell for the Automotive Industry

Liiv, Oliver January 2020 (has links)
Energy systems in every part of the world are experiencing accelerated shifts towards more sustainable solutions which will bring far-reaching changes to our daily lives. These rapid transitions will bring impactful and vital changes to the way we fuel our cars, heat our homes and power our industries in the approaching decades. [1] The automotive sector is in high pace to electrify their cars. The number of electric passengercar sales is expected to increase by more than a factor of 60 between 2018 to 2050. Which means by that time there could be approximately 2 billion EVs on the roads and they all need batteries to run on. [1] ManyEuropean electric vehicle manufacturers have started marketing their future models globally, but automotiveli.-ion battery manufacturing capacity in Europe is merely 2.1% of the total global automotive li-ion batteryproduction. [2] Increase in sales of EV-s and energy storage systems drives the demand for li-ion batteries. This research is conducted in collaboration with Northvolt, one of the newcomers to the li-ion batterymanufacturing market in Europe. Northvolt is a Swedish-founded company in 2016, and despite its young age, Northvolt has prominent partners including BMW Group, Epiroc, Scania and the Volkswagen Group. Northvolt is with global ambition to produce the world's greenest battery cell with minimal possible carbon footprint in its Gigafactory in Sweden with 32GWh annual manufacturing capacity. Also, together with Volkswagen a 50/50 joint venture has been established to produce batteries in a 16GWh factory in Germany. After entering in different supplier agreements, Northvolt has sold a considerable amount of its first Gigafactory NV Ett production capacity to its key customers with a united equivalent of over $13billion until 2030. [3]Setting up lithium-ion battery factories for the automotive industry is a challenging task. It requires high speed and flexibility to keep up with the growing demand in a short time and still meeting all the stakeholder's requirements while keeping the highest environmental standards in place during production. To keep up with the growing demand and customer requirements a state-of.the-art industrialization project management strategy is developed. Therefore, state-of.the-art automotive project management, new product industrialization and development practices are investigated together with the best practices from the wider industry. Furthermore, Northvolt's current industrialization project management strategies are examined, and improvement proposals and tools are developed to ramp-up the current and future factories with shorter time, less cost and highest possible quality. The main aim of the thesis is to develop a project management solutions to lead industrialization of li-ionbattery Giga-factories successfully and help Northvolt fuel our cars, heat our homes, and power our industries more sustainably and innovatively. The expected outcome of the thesis is five tools developed that support the industrialization of LIB production facilities in Europe to increase the EU LIB manufacturing capacity. / Energisystem genomgår en snabb omväxling till allt mer hållbara lösningar, vilket kommer påverka våra liv markant. Dessa snabba omväxlingar kommer påverka samt främja sättet hur vi driver våra bilar, värmer våra hus och försörjer våra industrier, flera år framåt. [1] Bilsektorn som har skiftat sitt fokus till elektrifiering av sina bilar, där antalet sålda elbilar förväntas att öka sextifaldigt mellan 2018 och 2050. Detta kommer att leda till att cirka 2 miljarder elbilar kommer att åka på vägarna globalt och alla dessabilar kommer behöva framförallt litiumjonbatterier. [1] Majoriteten av biltillverkare i Europa har börjatutveckla framtida elektrifierade bilmodeller. Tillverkningen av litiumjonbatterier för elbilar i Europa utgörendast 2.1 % av den globala tillverkningen totalt. [2] En ökad försäljning av elbilar och även av produkterför energilagring, ökar efterfrågan på litiumjonbatterier. Den här undersökningen har tagits fram i samarbete med Northvolt som är en av nykomlingarna inomtillverkningen av litiumjonbatterier i Europa. Northvolt är ett svenskt bolag som startades 2016 och trotsdess tidiga fas, har de lyckats samverka med prominenta samarbetspartners som BMW group, Epiroc, Scania och Volkswagen group. Northvolts ambition är att skapa världens grönaste batteri med ett minimalt klimatavtryck. Denna produkt utvecklas i deras så kallade Gigafactory som ligger i Skellefteå och vars årliga produktion uppnår 32 Gwh. Utöver det har Northvolt i samarbete med Volkswagen fått i uppdrag att bygga upp en batterifabrik i Tyskland, vars tillverkningskapacitet kommer att uppnå till 16Gwh årligen. Efter att ha ingått i flera leverantörsavtal har Northvolt sålt en avsevärd mängd av sin produktionskapacitet för den planerade fabriken Gigafactory NV Ett till sina nyckelkunder. Detta motsvarar en investering på 13 miljarder dollar fram till 2030. [3]Att etablera en fabrik som tillverkar litiumjonbatterier för bilindustrin är en utmanande uppgift. Det kräversnabba beslut och flexibilitet för att hålla jämna steg med den växande efterfrågan på batterier av denna typ. Batterierna ska hålla måttet för de krav som kunderna har, och även ska de uppfylla alla internationella standarder för ett miljövänligt batteri.För att kunna upprätthålla den växande efterfrågan och kundkraven utvecklas nya metoder inom projektledning för att effektivisera produktionen. Det allra senaste praxis i projektledning, produktion och produkttillverkning inom bilindustrin analyseras. Dessutom beaktas senaste metoderna och praxis från andra industrier. Vidare kartläggs northvolts nuvarande strategi för deras hantering av produktionsfasen för att föreslå förbättringar och verktyg, som kan effektivisera uppbyggnaden och driften av framtida fabriker. Huvudsyftet med denna avhandling är att utveckla nya metoder inom projektledning för att kunnautveckla produktionsfasen för framtida fabriker som tillverkar litiumjonbatterier. Detta kommer leda tillatt Northvolt kommer vara en del av våra framtida liv genom att hjälpa oss att driva våra fordon, värma våra hem och driva våra fabriker på ett hållbart och effektivt sätt. Det förväntade resultatet i denna avhandling är fem utvecklade verktyg som stödjer utbyggnaden av Litiumjonbatteri fabriker i Europa föratt öka dess totala årliga produktion.
107

Framtida behov av litium och kobolt för produktion av litium-jonbatterier vid Northvolt Ett i Skellefteå / Projecting future demand for lithium and cobalt at Northvolt Ett in Skellefteå

Stone Pöldma, Sofia January 2022 (has links)
Den ökande efterfrågan på laddbara bilar medför även en ökad efterfrågan på vissa metaller som krävs i framställande av tillhörande batterier. Efterfrågan på metaller som litium och kobolt ökar drastiskt. Samtidigt associeras utvinning av litium och kobolt med ett flertal hållbarhetsproblem som främst påverkar redan sårbara människor. För att minska de ohållbara konsekvenserna av råvaruextraktion är en möjlighet att öka andelen återvunnet material i nyproduktionen av litiumjonbatterier. Visserligen är återvinning en viktig komponent i batteritillverkningen, men det är ej totalt okomplicerat att skifta produktionen från nyutvunnen metall till återvunnen. Dessa svårigheter kan härledas till elbilsmarknadens exponentiella ökning i omfång vilket kräver mer metall för produktion än vad som kan mötas av återvunnet material.  Denna studie utvecklar och presenterar matematiska modeller i Microsoft Excel som uppskattar beräknad efterfrågan av nybruten litium och kobolt från år 2022 till 2050 i litium- jonbatterifabriken Northvolt Ett i Skellefteå. Modellerna baseras på antaganden från tidigare studier vilka tolkas i en litteraturgenomgång. Flertalet alternativa scenarion i återvinningsandelar, metallintensitet per energilagringsenhet och framtida batteriteknologi är samtliga konsistenta med litteraturgenomgången och brukas i beräkningarna. Resultaten visar att det, oavsett återvinningsandel och metallintensifiering, finns ett kontinuerligt behov av nyextraktion av litium för att möta efterfrågan vid Northvolt Ett under hela tidsperioden. Nybrytning av kobolt är enligt modelleringen som längst nödvändigt till år 2048. Dessutom, om högre återvinning kan uppnås, eller till och med en utfasning av kobolt i batteriproduktionen, kan behovet av brytning av kobolt för batteriproduktion vid Northvolt Ett nollställas redan 2030. Resultaten visar enhälligt att åtgärder som metallintensifiering och återvinning ej är tillräckligt för att undvika beroende av ny brytning av litium för batteriproduktion, men har motsatt effekt för behovet av nybruten kobolt. / The rising demand for chargeable vehicles entails a rising demand for certain metals needed in the manufacturing of the vehicles’ appurtenant batteries. The demand for metals such as lithium and cobalt are growing drastically. At the same time, the extraction of lithium and cobalt is associated with numerous sustainability issues that primarily affect the already vulnerable. To diminish the unsustainable consequences of primary commodity extraction; recycling is seen as a way of decreasing primary metal in lithium-ion battery production in favour of recycled materials. Admittedly, recycling is an important component of the battery industry. However, there are difficulties in substituting primary metal for recycling. These difficulties come down to the exponential growth of the electric vehicle market which demands more metal for production than can be met by batteries recycled at the end of life. As well as providing secondary commodities for battery production it is important that end of life electric vehicle batteries are recycled in order to prevent harmful pollution caused by landfill.  The study develops and presents mathematical models in Microsoft Excel that estimates the projected demand for primary metal between the years of 2022 and 2050 in the lithium-ion vehicle battery production plant Northvolt Ett in Skellefteå, Sweden. The models are based on assumptions from earlier work retrieved from a literature review. Several alternative scenarios in recycling rates, metal intensity per energy storage unit and battery technology in the future all consistent with the literature review are used in the calculations. The results show that regardless of recycling rates and metal intensifying rates there is a need for continuous extraction of primary lithium for electric vehicle battery production at Northvolt Ett during the entire modelled period. Nonetheless, extraction of primary cobalt will at most be needed until 2048. Additionally, if higher recycling rates are adopted or even a phase out of cobalt in production, the need for mining cobalt for battery production at Northvolt Ett could be diminished as early as 2030. The results clarify that decreasing the amount of lithium in batteries and recycling is not enough to avoid a dependence on primary sources as production rates grow, but this could however be the case for cobalt.
108

PHYSICS-BASED MODELLING AND SIMULATION FRAMEWORK FOR MULTI-OBJECTIVE OPTIMIZATION OF LITHIUM-ION CELLS IN ELECTRIC VEHICLE APPLICATIONS

Ashwin Pramod Gaonkar (12469470) 27 April 2022 (has links)
<p>  </p> <p>In the last years, lithium-ion batteries (LIBs) have become the most important energy storage system for consumer electronics, electric vehicles, and smart grids. The development of lithium-ion batteries (LIBs) based on current practice allows an energy density increase estimated at 10% per year. However, the required power for portable electronic devices is predicted to increase at a much faster rate, namely 20% per year. Similarly, the global electric vehicle battery capacity is expected to increase from around 170 GWh per year today to 1.5 TWh per year in 2030--this is an increase of 125% per year. Without a breakthrough in battery design technology, it will be difficult to keep up with the increasing energy demand. To that end, a design methodology to accelerate the LIB development is needed. This can be achieved through the integration of electro-chemical numerical simulations and machine learning algorithms.</p> <p><br></p> <p>To help this cause, this study develops a design methodology and framework using Simcenter Battery Design Studio® (BDS) and Bayesian optimization for design and optimization of cylindrical cell type 18650. The materials of the cathode are Nickel-Cobalt-Aluminum (NCA)/Nickel-Manganese-Cobalt-Aluminum (NMCA), anode is graphite, and electrolyte is Lithium hexafluorophosphate (LiPF6). Bayesian optimization has emerged as a powerful gradient-free optimization methodology to solve optimization problems that involve the evaluation of expensive black-box functions. The black-box functions are simulations of the cyclic performance test in Simcenter Battery Design Studio. </p> <p>The physics model used for this study is based on full system model described by Fuller and Newman. It uses Butler-Volmer Equation for ion-transportation across an interface and solvent diffusion model (Ploehn Model) for Aging of Lithium-Ion Battery Cells. The BDS model considers effects of SEI, cell electrode and microstructure dimensions, and charge-discharge rates to simulate battery degradation. Two objectives are optimized: maximization of the specific energy and minimization of the capacity fade. We perform global sensitivity analysis and see that thickness and porosity of the coating of the LIB electrodes that affect the objective functions the most. As such the design variables selected for this study are thickness and porosity of the electrodes. The thickness is restricted to vary from 22 micron to 240 microns and the porosity varies from 0.22 to 0.54. </p> <p>Two case studies are carried out using the above-mentioned objective functions and parameters. In the first study, cycling tests of 18650 NCA cathode Li-ion cells are simulated. The cells are charged and discharged using a constant 0.2C rate for 500 cycles. In the second case study a cathode active material more relevant to the electric vehicle industry, Nickel-Manganese-Cobalt-Aluminum (NMCA), is used. Here, the cells are cycled for 5 different charge-discharge scenarios to replicate charge-discharge scenario that an EVs battery module experiences. The results show that the design and optimization methodology can identify cells to satisfy the design objective that extend and improve the pareto front outside the original sampling plan for several practical charge-discharge scenarios which maximize energy density and minimize capacity fade. </p>
109

Electrochemical Behavior of the High Entropy Oxide (Mg,Co,Ni,Zn)1-xLixO (x=0,35) / Elektrokemiska Beteenden hos högentropioxiden (Mg,Co,Ni,Zn)1-xLixO (x=0,35)

Sandström Kinnane, Rasmus January 2022 (has links)
Today's society is currently developing lithium-ion batteries to eventually replace the use of fossil fuels. High entropy oxides is a new type of material to use as an anode in the lithium-ion battery. These high entropy oxides may consist of a few different transition metals including lithium and oxygen. In this report was (MgCoNiZn)1-xLixO synthesized with a method called Pechini with a molar fraction of x=0.35. This study compares the results from a reference study that has shown the potential of the electrochemical characteristics of (MgCoNiZn)1-xLixO for application as anode in a lithium-ion battery.  The synthesis starts with a heating step to remove all the organics in the composition. The powder consists of several structures and, therefore goes through a calcination step to dissolve all of the intermediate phases into the rock-salt structure. The structure of the powder had a lattice constant of 4,138Å. The powder was made into a slurry containing Carbon black, PVDF and NMP to later get coated by a Dr. Blade. After drying the coating the cell was then assembled with lithium as metal cathode and 1M LiPF6 in 1:1 EC/DMC as electrolyte. After the cell was assembled it, went through electrochemical properties test using a potentiostat and the cell being inside a in a climate chamber at 25°C.  7 cycles were done to plot a cyclic voltammetry graph as well as a discharge-charge test was performed. The cyclic voltammetry and discharge-charge test was run with a voltage range of 0,053 V. The discharge-charge test was run at a current density of 100 mA/g and a constant current of 42,68 mA. / Dagens samhälle genomgår en stor utveckling av litium-jon batterier för att kunna ersätta användningen av fossila bränslen. Höga entropi oxider är ny typ av material som används som anod material för litiumjonbatterier. Dessa höga entropi oxider kan bestå av en rad olika övergångsmetaller inklusive litium och syre i sammansättningen. I den här rapporten var (MgCoNiZn)1-xLixO syntetiserad med en metod som heter Pechini med ett molbråk på x=0,35. En studie har visat potentialen i dem elektrokemiska beetenden av (MgCoNiZn)1-xLixO till applicering som en anode i ett litiumjon batteri.  Syntetiseringen började med ett uppvärmningsteg för att bränna bort alla organiska föreningar. Resulterade pulvret bestod av olika strukturer, och till ett kalcinerings steg för att lösa upp mellanfaserna till NaCL-struktur. Strukturen på pulvret hade en gitter constant på 4,138 Å. Pulvret gjordes till en slurry som innehåller amorft kol, PVDF och NMP för att sedan belägga elektroden med en Dr.Blade. Efter beläggningen har fått torka monterades cellen med litium som katod och 1M LiPF6 in 1:1 EC/DMC som elektrolyt. Tester utfördes på cellen med hjälp av en potentiostat medans cellen var förvaren i en klimatkammare i 25°C.  7 stycken cykler kördes för att plotta en cyklisk voltametri graf samt en urladdning-laddning prov utfördes. Cykliska voltametrin och urladdning-laddnings prov utfördes med ett spänningsintervall på 0,05-3,0V. Urladdning-laddnings provet hade en strömtäthet på 100 mA/g och en konstant ström på 42,68 mA.
110

Lithium-Ion Battery Electrolyte Evaporation

Dylan Michael Poe (15348418) 29 April 2023 (has links)
<p> Energy storage has received much attention due to the increasing use of energy, especially renewable energy. Lithium-ion batteries have great characteristics for electrical energy storage. Higher specific energy density, cycle life, cell voltage, shorter charge times gives lithium-ion batteries favorable energy storage characteristics over other battery chemistries. Although lithium-ion batteries are increasing in use for electrical energy storage, their safety still poses an engineering problem. When lithium-ion batteries are abused, they can enter thermal runaway. This event is dangerous as it can eject hot gases and shrapnel. Previous studies focused on different aspects of thermal runaway, for example, heat generation from chemical reactions, propagation to other cells, and the physics of gas venting. One phenomenon that has not received much attention is the evaporation of the electrolyte out of a failed lithium-ion battery. Understanding the effect of electrolyte evaporation is key to having a more complete understanding of thermal runaway. In this thesis, the physics of electrolyte evaporation is studied with the purpose of developing more accurate thermal abuse models. An evaporation model was developed, based on porous drying theory and a 1-D liquid diffusion process. Experiments were conducted to identify the liquid diffusion coefficient which governs the rate of electrolyte transport within the porous separator within the battery. The 1-D liquid diffusion model was then implemented into an existing thermal abuse model and exercised for a typical oven test scenario. Results showed that the physics-based evaporation model resulted in excellent agreement with experimental data at different oven temperatures.</p>

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