Hochleistungsfähige Lithium-Ionen-Batterien sind insbesondere von der hohen spezifischen Kapazität ihrer Elektrodenmaterialien abhängig. Intermetallische Phasen sind vielversprechende Kandidaten für alternative Anodenmaterialien mit verbesserten spezifischen Kapazitäten (LiAl: 993 Ah/kg; Li22Si5: 4191 Ah/kg) gegenüber den derzeit vielfach verwendeten Kohlenstoff-Materialien (LiC6: 372 Ah/kg). Nachteilig ist jedoch, dass die kristallinen Phasenumwandlungen während der Lade-Entlade-Prozesse Volumenänderungen von 100-300% verursachen. Durch die Sprödigkeit der intermetallischen Phasen führt dies zum Zerbrechen des Elektrodenmaterials und damit zum Kontaktverlust. Um Lithiierungs- und Delithiierunsprozesse ohne kristalline Phasenumwandlungen zu realisieren und somit große Volumenänderungen zu vermeiden, wurden amorphe Al-Legierungen untersucht. In amorphe, mittels Schmelzspinnen hergestellte Legierungen (Al86Ni8La6 und Al86Ni8Y6) kann beim galvanostatischen Zyklieren nur sehr wenig Li eingelagert werden. Da kristalline Phasenumwandlungen im amorphen Zustand nicht möglich sind, wird für die Diffusion und Einlagerung von Li-Ionen ein ausreichendes freies Volumen im amorphen Atomgerüst benötigt. Die Dichtemessung der Legierungen zeigt, dass dieses freie Volumen für eine signifikante Lithiierung nicht ausreichend ist. Wird Li bereits in die amorphe Ausgangslegierung integriert, können Li-Ionen auf elektrochemischem Wege aus ihr entfernt und auch wieder eingebaut werden. Die neuartige Legierung Al43Li43Ni8Y6, die Li bereits im Ausgangszustand enthält, konnte mittels Hochenergiemahlung als amorphes Pulver hergestellt werden. Verglichen mit den Li-freien amorphen Legierungen Al86Ni8La6 bzw. Al86Ni8Y6 und ihren kristallisierten Pendants zeigt diese neu entwickelte, amorphe Legierung eine signifikant höhere Lithiierungsfähigkeit und erreicht damit eine spezifische Kapazität von ca. 800 Ah/kg bezogen auf den Al-Anteil. Durch den Abrieb des Stahlmahlbechers enthält das Pulver Al43Li43Ni8Y6 einen Fe-Anteil von ca. 15 Masse%. Dieses mit Fe verunreinigte Material zeigt besonders bei niedrigen Laderaten eine bessere Zyklenstabilität als ein im abriebfesten Siliziumnitrid-Becher gemahlenes Pulver der gleichen Zusammensetzung. Mittels Mössbauerspektroskopie wurde nachgewiesen, dass das Pulver z.T. oxidisches Fe enthält. Dieses kann über Konversionsmechanismen einen Beitrag zur spezifischen Kapazität leisten. / High-energy Li-ion batteries exceedingly depend on the high specific capacity of electrode materials. Intermetallic alloys are promising candidates to be alternative anode materials with enhanced specific capacities (LiAl: 993 Ah/kg; Li22Si5: 4191 Ah/kg) in contrast to state-of-the-art techniques, dominated by carbon materials (LiC6: 372 Ah/kg). Disadvantageously the phase transitions during the charge-discharge processes, induced by the lithiation process, cause volume changes of 100-300 %. Due to the brittleness of intermetallic phases, the fracturing of the electrode material leads to the loss of the electrical contact. In order to overcome the huge volume changes amorphous Al-based alloys were investigated with the intension to realize the lithiation process without a phase transformation. Amorphous powders (Al86Ni8La6 and Al86Ni8Y6) produced via melt spinning and subsequent ball milling only show a minor lithiation during the electrochemical cycling process. This is mainly caused by the insufficient free volume, which is necessary to transfer and store Li-ions, since phase transitions are impossible in the amorphous state. If Li is already integrated into the amorphous alloy, Li-ions can easily be removed and inserted electrochemically. The new alloy Al43Li43Ni8Y6 contains Li already in its initial state and could be prepared by high energy milling as an amorphous powder. Compared with the Li-free amorphous alloys Al86Ni8La6 or Al86Ni8Y6 and their crystalline counterparts, this newly developed amorphous alloy achieves a significantly higher lithiation and therefore reaches a specific capacity of 800 Ah/kg, based on the Al-content. By the abrasion of the steel milling vials the powder contains a wear debris of 15 mass% Fe. This contaminated material shows a better cycling stability than a powder of the same composition, milled in a non-abrasive silicon nitride vial. By means of Mössbauer spectroscopy has been shown that the wear debris contains Fe oxides. This may contribute to the enhancement of the specific capacity about conversion mechanisms.

Li-ion thin film battery technology has attracted much attention in recent years due to its highest need in portable electronic devices. Development of new materials for lithium ion battery (LIB) is very crucial for enhancement of the performance. LIB can supply higher energy density because Lithium is the most electropositive (-3.04V vs. standard hydrogen electrode) and lightest metal (M=6.94 g/mole). LIBs show many advantages over other kind of batteries such as, high energy density, high power density, long cycle life, no memory effect etc. The major work presented in this thesis is on the development of nanostructured materials for anode of Li-ion battery. It involves the synthesis and analysis of grapheme nanosheet (GNS) and its performance as anode material in Li ion battery. We studied the synthesis of GNS over different substrates and performed the anode studies. The morphology of GNS has great impact on Li storage capacity. Tin and Tin oxide nanostructures have been embedded in the GNS matrix and their electrochemical performance has been studied. Chapter 1 gives the brief introduction about the Li ion batteries (LIBs), working and background. Also the relative advantages and characterization of different electrode materials used in LIBs are discussed. Chapter 2 discusses various experimental techniques that are used to synthesize the electrode materials and characterize them. Chapter3 presents the detailed synthesis of graphene nanosheet (GNS) through electron cyclotron resonance (ECR) microwave plasma enhanced chemical vapor deposition (ECR PECVD) method. Various substrates such as metallic (copper, Ni and Pt coated copper) and insulating (Si, amorphous SiC and Quartz) were used for deposition of GNS. Morphology, structure and chemical bonding were analyzed using SEM, TEM, Raman, XRD and XPS techniques. GNS is a unique allotrope of carbon, which forms highly porous and vertically aligned graphene sheets, which consist of many layers of graphene. The morphology of GNS varies with substrate. Chapter 4 deals with the electrochemical studies of GNS films. The anode studies of GNS over various substrates for Li thin film batteries provides better discharge capacity. Conventional Li-ion batteries that rely on a graphite anode have a limitation in the capacity (372 mAh/g). We could show that the morphology of GNS has great effect in the electrochemical performance and exceeds the capacity limitation of graphite. Among the electrodes PtGNS shown as high discharge capacity of ~730 mAh/g compare to CuGNS (590 mAh/g) and NiGNS (508 mAh/g) for the first cycle at a current density of 23 µA/cm2. Electrochemical impedance spectroscopy provides the various cell parameters of the electrodes. Chapter 5 gives the anodic studies of Tin (Sn) nanoparticles decorated over GNS matrix. Sn nanoparticles of 20 to 100nm in size uniformly distributed over the GNS matrix provides a discharge capacity of ~1500 mAh/g mAh/g for as deposited and ~950 mAh/g for annealed Sn@GNS composites, respectively. The cyclic voltammogram (CV) also shows the lithiation and delithiation process on GNS and Sn particles. Chapter 6 discusses the synthesis of Tinoxide@GNS composite and the details of characterization of the electrode. SnO and SnO2 phases of Tin oxide nanostructures differing in morphologies were embedded in the GNS matrix. The anode studies of the electrode shows a discharge capacity of ~1400 mAh/g for SnO phase (platelet morphology) and ~950 mAh/g for SnO2 phase (nanoparticle morphology). The SnO phase also exhibits a good coulumbic efficiency of ~95%. Chapter 7 describes the use of SnO2 nanowire attached to the side walls of the GNS matrix. A discharge capacity of ~1340 mAh/g was obtained. The one dimensional wire attached to the side walls of GNS film and increases the surface area of active material for Li diffusion. Discharge capacity obtained was about 1335 mAhg-1 and the columbic efficiency of ~86% after the 50th cycle. The research work carried out as part of this thesis, and the results have summarized in chapter 8.

Ce mémoire contribue à l’amélioration des performances d’une source de stockage hybride embarquée alimentant un véhicule électrique. La solution investiguée est composée de l’association de batteries Li-ion et de super condensateurs, dans le but d’obtenir, par rapport aux solutions classiques, un gain en masse et en durée de vie pour une certaine plage d’autonomie du véhicule. Notre objectif est de mettre à profit l’utilisation de nouvelles méthodes de gestion de la source hybride et de quantifier le gain obtenu. Un modèle multi-physique incluant les aspects électrique, thermique et vieillissement a été développé et intégré dans l’algorithme de gestion d’énergie afin d’évaluer la dégradation progressive des performances des éléments de stockage au cours des cycles de conduite selon la stratégie de gestion implantée. De nouvelles stratégies de gestion ayant pour objectif d’agir sur la durée de vie ont été évaluées. Leur impact sur les performances de la source en termes de masse, coût et durée de vie a pu être quantifié et montre bien que par une meilleure gestion des puissances, il est possible de mieux utiliser le stockeur hybride, ouvrant ainsi la voie à de nouvelles approches de gestion d’énergie pour ces systèmes. / This thesis contributes to the improvement of hybrid embedded source performances supplies an electric vehicle. The studied solution is composed of Li-ion batteries and supercapacitors hybridization, with an aim to achieve improved performances in terms of weight and lifetime over traditional solutions. Our main goal is to take the best advantage of new energy management strategies of the hybrid embedded source and quantify obtained improvements. A multi-physic model including electric, thermal and aging behaviors is developed and integrated into the algorithm of energy management in order to evaluate the gradual degradation of storage components performances during driving cycles and implemented control strategy. New energy management strategies intended to act on the lifetime of hybrid embedded source have been evaluated. Their impact on the performances of the source in terms of weight, cost and lifetime has been quantified and clearly shows that it is possible to make better use of hybrid embedded source thanks to a good power sharing, thus opening the way to new approaches of energy management for these systems.

La sécurité de plusieurs systèmes électriques est fortement dépendante de la fiabilité de leur bloc-batterie à base de piles aux ions lithium (Li-ion). Par conséquent, ces batteries doivent être suivis et contrôlés par un système de gestion des batteries (BMS). Le BMS interagit avec toutes les composantes du bloc-batterie de façon à maintenir leur intégrité. La principale composante d’un BMS est un modèle représentant le comportement des piles Liion et capable de prédire ses différents points d’opération. Dans les industries de l’électronique et de l’automobile, le BMS repose habituellement sur des modèles empiriques simples. Ceux-ci ne sont cependant pas capables de prédire les paramètres de la batterie lorsqu’elle vieillit. De plus, ils ne sont applicables que pour des piles spécifiques. D’un autre côté, les modèles électrochimiques sont plus sophistiqués et plus précis puisqu’ils sont basés sur la résolution des équations de transport et de cinétique électrochimique. Ils peuvent être utilisés pour simuler les caractéristiques et les réactions à l’intérieur des piles aux ions lithium. Pour résoudre les équations des modèles électrochimiques, il faut connaître les différents paramètres électrochimiques et thermo-physiques de la pile. Les variables les plus significatives des piles Li-ion peuvent être divisées en 3 catégories : les paramètres géométriques, ceux définissant les matériaux et les paramètres d’opération. Les paramètres géométriques et de matériaux peuvent être facilement obtenus à partir de mesures directes ou à partir des spécifications du manufacturier. Par contre, les paramètres d’opération ne sont pas faciles à identifier. De plus, certains d’entre eux peuvent dépendre de la technique de mesure utilisée et de l’âge. Finalement, la mesure de certains paramètres requiert le démantèlement de la pile, une procédure risquée et destructive. Plusieurs recherches ont été réalisées afin d’identifier les paramètres opérationnels des piles aux ions lithium. Toutefois, la plupart de ces études ont porté sur l’estimation d’un nombre limité de paramètres et se sont attardées sur un seul type de matériau pour l’électrode positive utilisé dans la fabrication des piles Li-ion. De plus, le couplage qui existe entre les paramètres électrochimiques et thermo-physiques est complètement ignoré. Le but principal de cette thèse est de développer une méthode générale pour identifier simultanément différents paramètres électrochimiques et thermo-physiques et de prédire la performance des piles Li-ion à base de différents matériaux d’électrodes positives. Pour atteindre ce but, une méthode inverse efficace a été introduite. Des modèles directs représentatifs des piles Li-ion à base de différents matériaux d’électrodes positives ont également été développés. Un modèle rapide et précis simulant la performance de piles Li-ion avec des électrodes positives à base de LiMn2O4 ou de LiCoO2 est présenté. Également, deux modèles ont été développés pour prédire la performance des piles Li-ion avec une électrode positive de LiFePO4. Le premier, appelé modèle mosaïque modifié (MM), est basé sur une approche macroscopique alors que le deuxième, appelé le modèle mésoscopique, est plutôt basé sur une approche microscopique. Des études d’estimation de paramètres ont été conduites en utilisant les modèles développés et des données expérimentales fournies par Hydro-Québec. Tous les paramètres électrochimiques et thermo-physiques des piles Li-ions ont été simultanément identifiés et appliqués à la prédiction de la performance des piles. Finalement, une technique en temps réel reposant sur des réseaux de neurones est introduite dans la méthode d’estimation des paramètres intrinsèques au piles Li-ion. / Abstract : The safety of many electrical systems is strongly dependent on the reliable operation of their lithium-ion (Li-ion) battery packs. As a result, the battery packs must be monitored by a battery management system (BMS). The BMS interacts with all the components of the system so as to maintain the integrity of the batteries. The main part of a BMS is a Li-ion battery model that simulates and predicts its different operating points. In the electronics and in the automobile industries, the BMS usually rests on simple empirical models. They are however unable to predict the battery parameters as it ages. Furthermore, they are only applicable to a specific cell. Electrochemical-based models are, on the other hand, more sophisticated and more precise. These models are based on chemical/electrochemical kinetics and transport equations. They may be used to simulate the Li-ion battery characteristics and reactions. In order to run the electrochemical-based mathematical models, it is imperative to know the different electrochemical and thermophysical parameters of the battery. The significant variables of the Li-ion battery can be classified into three groups: geometric, material and operational parameters. The geometric and material parameters can be easily obtained from direct measurements or from the datasheets provided by the manufacturer. The operational properties are, on the other hand, not easily available. Furthermore, some of them may vary according to the measurement techniques or the battery age. Sometimes, the measurement of these parameters requires the dismantling of the battery itself, which is a risky and destructive procedure. Many investigations have been conducted to identify the operational parameters of Li-ion batteries. However, most of these studies focused on the estimation of limited parameters, or considered only one type of the positive electrode materials used in Li-ion batteries. Moreover, the coupling of the thermophysical parameters to the electrochemical variables is ignored in all of them. The main goal of this thesis is to develop a general method to simultaneously identify different electrochemical and thermophysical parameters and to predict the performance of Li-ion batteries with different positive electrode materials. To achieve this goal, an effective inverse method is introduced. Also, direct models representative of Li-ion batteries are developed, applicable for all of the positive electrode materials. A fast and accurate model is presented for simulating the performance of the Li-ion batteries with the LiMn2O4 and LiCoO2 positive electrodes. Moreover, two macro- and micro-based models are developed for predicting the performance of Li-ion battery with the LiFePO4 positive electrode, namely the Modified Mosaic (MM) and the mesoscopic-based models. The parameter estimation studies are then implemented by means of the developed direct models and experimental data provided by Hydro-Québec. All electrochemical and thermophysical parameters of the Li-ion batteries are simultaneously identified and applied for the prediction of the battery performance. Finally, a real-time technique resting on neural networks is used for the estimation of the Li-ion batteries intrinsic parameters.

Presented work investigates the problem of secondary lithium-ion cells and the different available cathode materials. We have prepared samples of LiFePO4 with the addition of different kinds of carbon materials such as Super P, Vulcan and expanded graphite. We have always created the sample with and without surfactant. Developed samples were compared by measuring electrochemical methods (cyclic voltammetry, charge and discharge cycles and impedance spectroscopy). We also modeled the three-point cell for measuring electrochemical electrode materials.

Au cours des dernières années, le développement des batteries Li-ion a révolutionné nos modes de vie. Compte tenu de la croissance exponentielle en batteries, le besoin se répercute sur les matériaux de base, qui sont entre autres, synthétisés à partir de sels de lithium de haute pureté. Nemaska Lithium, une entreprise partenaire du projet, est reconnue en tant que nouveau producteur d’hydroxyde de lithium, par l’entremise d’un procédé électromembranaire breveté. Comparativement au procédé conventionnel, la solution mise en place est l’une des méthodes la plus économique et écologique à l’échelle mondiale. Dans le but de diminuer encore plus les coûts énergétiques du procédé, l’usage d’une anode dépolarisée à l’hydrogène ((ADH); H2(g) ⇄ 2H+(aq) +2é; E=0,00 V) est considérée. Cette approche demande une certaine compréhension et optimisation de l’électrode à des fins d’adaptation pour l’électrolyse. Ainsi, ce travail tant fondamental qu’appliqué a été réalisé afin d’étudier les phénomènes se produisant à l’ADH. Dans un premier temps, une étude portée sur la cinétique de réaction de l’oxydation de l’hydrogène à l’aide d’une électrode à disque tournant est réalisée. L’influence d’ions lithium et d’une couche catalytique composite sur l’efficacité de la réaction a ainsi pu être démontrée. L’identification des limitations du système a ensuite permis l’optimisation de l’ADH à l’aide d’un plan d’expérience. L’ADH est composée d’un ionomère, d’un catalyseur et d’un support à catalyseur, qui ont des propriétés intrinsèques ayant un impact direct sur l’efficacité et la durabilité de celle-ci. Conséquemment, pour une étude de performance et d’optimisation, plusieurs configurations d’assemblage d’électrode à membrane (MEA) ont été considérées visant à faire varier les proportions des différentes composantes avec un plan d’expérience. Ce projet a ainsi permis l’étude menant à une meilleure compréhension d’une nouvelle technologie d’électrolyse membranaire. / In recent years, the development of Li-ion batteries has revolutionized our lifestyles. Given the exponential demand for batteries, the requirement is for base materials, which are synthesized from high-purity lithium salts. Nemaska Lithium, a partner in the project, is recognized as a new producer of lithium hydroxide, using a patented electromembrane process. Compared to the conventional process, this solution is one of the most economical and environmentally friendly methods worldwide. In order to further reduce the energy costs of the process, the use of a hydrogen depolarized anode ((HDA); H2(g) ⇄ 2H+(aq) +2é; E0=0,00 V) is considered. This approach requires some understanding and optimization of the electrode for electrolysis adaptations. Thus, this fundamental and applied work was conducted to study the phenomena occurring at the HDA. First, a study on the kinetics of the hydrogen oxidation reaction using a rotating disk electrode is performed. The influence of lithium ions and a composite catalytic layer on the efficiency of the reaction was demonstrated. The identification of system limitations allowed the optimization of the DHA using a design of experiment. The components of a HDA have intrinsic properties which have a direct impact on its efficiency and durability. They consist of an ionomer, a catalyst, and a catalyst support. Consequently, for a performance and optimization study, several membrane electrode assembly (MEA) configurations were considered in order to vary the proportions of the different components with a design of experiment. This study provided a better understanding and development of this new membrane electrolysis technology.

Indiana University-Purdue University Indianapolis (IUPUI) / Since 1990s, rechargeable Li-ion batteries have been widely used in consumer electronics such as cell phones, global positioning systems (GPS), personnel digital assistants (PDA), digital cameras, and laptop computers. Recently Li-ion batteries received considerable attention as a major power source for electric vehicles. However, significant technical challenges still exist for widely deploying Li-ion batteries in electric vehicles. For instance, the energy density of Li-ion batteries is not high enough to support a long-distance commute. The Li-ion batteries used for the Nissan Leaf and Chevy Volt only can support 50 – 100 miles per charge. The cost of Li-ion battery packs in electric vehicles is still high. The battery pack for the Chevy Volt costs about $8,000, and the larger one in the Nissan Leaf costs about $12,000. To address these problems, new Li-ion battery electrode materials with high energy density and low cost should be developed. Among Li-ion battery cathode materials, vanadium pentoxide, V2O5, is one of the earliest oxides studied as a cathode for Li-ion batteries because of its low cost, abundance, easy synthesis, and high energy density. However, its practical reversible capacity has been limited due to its irreversible structural change when Li insertion is more than x = 1. Tremendous efforts have been made over the last twenty years to improve the phase reversibility of LixV2O5 (e.g., 0 ≤ x ≤ 2) because of vanadium pentoxides’ potential use as high capacity cathodes in Li-ion batteries. In this thesis, a new strategy was studied to develop vanadium pentoxide cathode materials with improved phase reversibility. The first study is to synthesize vanadium oxide cathodes via a new chemical route – creating a phase transformation from the vanadium sulfide to oxide. The β-Na0.33V2O5 was prepared via a new method of chemical synthesis, involving the chemical transformation of NaVS2 via heat-treatment at 600 °C in atmospheric air. The β-Na0.33V2O5 particles were well crystalized and rod-shaped, measuring 7–15 μm long and 1–3 μm wide with the formation of the crystal defects on the surface of the particles. In contrast to previous reports contained in the literature, Na ions were extracted, without any structural collapse, from the β -Na0.33V2O5 structure and replaced with Li ions during cycling of the cell in the voltage range, 1.5 V to 4.5 V. This eventually resulted in a fully reversible Li intercalation into the LixV2O5 structure when 0.0 ≤ x ≤ 2.0. The second study is to apply the synthesis method to LiVS2 for the synthesis of β׳-LixV2O5 for use as a high performance cathode. The synthesis method is based on the heat treatment of the pure LiVS2 in atmospheric air. By employing this method of synthesis, well-crystalized, rod-shaped β׳-LixV2O5 particles 20 – 30 μm in length and 3 – 6 μm in width were obtained. Moreover, the surface of β׳-LixV2O5 particles was found to be coated by an amorphous vanadium oxysulfide film (~20 nm in thickness). In contrast to a low temperature vanadium pentoxide phase (LixV2O5), the electrochemical intercalation of lithium into the β׳-LixV2O5 was fully reversible where 0.0 < x < 2.0, and it delivered a capacity of 310 mAh/g at a current rate of 0.07 C between 1.5 V and 4 V. Good capacity retention of more than 88% was also observed after 50 cycles even at a higher current rate of 2 C. The third study is the investigation of NaVS2 as a cathode intercalation material for sodium ion batteries. We have shown that reversible electrochemical deintercalation of x ~ 1.0 Na per formula unit of NaxVS2, corresponding to a capacity of ~200 mAh/g, is possible. And a stable capacity of ~120 mAh/g after 30 cycles was observed. These studies show that the new chemical synthesis route for creating a phase transformation from the vanadium sulfide to oxide by heat treatment in air is a promising method for preparing vanadium oxide cathode material with high reversibility. Although this sample shows a relatively low voltage range compared with other cathodes such as LiCoO2 (3.8 V) and LiFePO4 (3.4 V), the large capacity of this sample is quite attractive in terms of increasing energy density in Li-ion batteries. Also, NaVS2 could be a promising cathode material for sodium ion batteries.

Four molecular germanates based on salicyl alcoholates, bis(dimethylammonium) tris[2-(oxidomethyl)phenolate(2-)]germanate (1), bis(dimethylammonium) tris[4-methyl-2-(oxidomethyl)phenolate(2-)]germanate (2), bis(dimethylammonium) tris[4-bromo-2-(oxidomethyl)phenolate(2-)]germanate (3) and dimethylammonium bis[2-tert-butyl-4-methyl-6-(oxidomethyl)phenolate(2-)][2-tert-butyl-4-methyl-6-(hydroxymethyl)phenolate(1-)]germanate (4), were synthesized and characterized including single crystal X-ray diffraction analysis. In the solid state, compounds 1 and 2 exhibit one-dimensional hydrogen bonded networks, whereas compound 4 forms separate ion pairs, which are connected by hydrogen bonds between the dimethylammonium and the germanate moieties. The potential of these compounds for thermally induced twin polymerization (TP) was studied. Germanate 1 was converted by TP to give a hybrid material (HM-1) composed of phenolic resin and germanium dioxide. Subsequent reduction with hydrogen provided a microporous composite containing crystalline germanium and carbon (Ge@C – C-1, germanium content ∼20%). Studies on C-1 as an anode material for Li-ion batteries revealed reversible capacities of ∼370 mA h gGe@C−1 at a current density up to 1384 mA g−1 without apparent fading for 500 cycles. / Dieser Beitrag ist aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich.

An increased amount of intermittent electricity production, more electric vehicles (EV), and an overall electrification of society may all cause a higher variability between the balance of supply and demand on the electric grid. Battery storage has been identified as a solution to the emerging problem asit can be charged during hours of low power demand and then discharged to help meet the power demand during peak loads. This master thesis investigates how characteristics from yearly power demand data can be defined so that a battery energy storage system (BESS) can be dimensioned for it and which parameters are important when dimensioning a BESS. The investment cost of the dimensioned BESS is investigated and calculated, and there is as well a general discussion of potentials, drivers, and barriers for a grid owner to implement a BESS. The master thesis includes a literature study and a case study performed together with Tekniska verken and its subsidiary company Tekniska verken Nät where three cases of varying sizes were investigated:• An EV charging station, with a peak power demand of up to 1 MW.• A distribution station, with an original peak power demand of close to 3 MW.• Purchased power from the regional grid, with a peak power demand of almost 152 MW. By dimensioning a BESS from a year-long data curve of the hourly power demand, a power limit was set. The highest peak power value over the power limit, the longest peak duration, and the highest energy peak were then identified to establish the curve characteristics. A battery storage was investigated to see if it could be used to meet the demand occurring when implementing a power limit to the yearly power demand curve. Batteries store electrical energy in the form of electrochemical energy and then transforms the energy back into electrical energy when needed and does so with varying efficiency according to the type of chemistry that is used in the battery. The so-called lithium ion (li-ion) battery is mostly used today and utilizes lithium in the shape of ions along with a metallic cathode and a carbon anode. The cathode and anode can vary in a li-ion battery chemistry, which varies its characteristics and means that there are multiple types of li-ion battery chemistry types. The specific li-ion battery chemistry lithium iron phosphate (LFP), was established as the most applicable battery due to its high energy density, easy to attain materials, general safety, maturity, and amount of discharge cycles it can handle throughout its lifetime. A BESS could be modelled from the LFP limitations and data curve for each case. The results showed that a short-duration variability of a power demand was a success factor for the implementation of a BESS. It allows the BESS to recharge often and the minimum required energy capacity could be lower and more optimal. An investment cost insecurity was established from literature when comparing estimates, as it could vary depending on the published date, used battery chemistry, taxes, and subsidies in the origin country of the literature. Therefore an estimate given by the Swedish transmission system operator (TSO), Svenska Kraftnät of 5-6 MSEK/MWh from a report published in late 2022 was deemed most relevant. An investment cost for each scenario in every case could be calculated and additional economical benefits relevant in the cases such as comparing to the cost of conventional grid reinforcement or economical gains from a lowered grid subscription were investigated. However, an overall conclusion that the investment cost of a BESS was too expensive to be deemed feasible and that there were no overwhelming economical gains from reducing the peak loads was made. A final generalization and discussion of drivers and barriers concluded that the applicability of a BESS can be identified by the defining characteristics of a demand curve. Moreover, it was found that the BESS investment cost was too high when only applying it for grid reinforcement methods. Although, a BESS can have additional benefits to the grid stability. The grid owner cannot however, own a BESS and use it on the frequency service market which otherwise would potentially make it economically feasible to strengthen the grid. The ultimate goal of the project is to help create a broader understanding of battery storage as part of the electrical network, where and when it can be applicable, and how one could go about investigating its use. / En ökad mängd variabel elproduktion, fler elbilar och en elektrifiering av samhället i helhet. Detta kommer skapa en högre variabilitet och därmed större obalans mellan tillförsel och efterfrågan på elnätet. Batterilagring har identifierats som en potentiell lösning till det ökade problemet då det kan laddas vid ett lågt effektbehov och urladdas vid ett högt effektbehov. Genom detta examensarbete kommer det undersökas hur karaktäristik från årliga effektkurvor kan definieras. Det görs i syfte av att dimensionera ett batterilagringssystem utefter datan. Därefter undersöks även vilka parametrar som är viktiga vid dimensioneringen av ett batterilagringssystem. Utefter de dimensionerade batterilagringssystemen tas även en investeringskostnad fram. En diskussion framförs även utifrån den generella potentialen, drivkrafter och barriärer som finns vid implementering av ett batterilagringssystem från perspektivet av en nätägare. Examensarbete består av en litteraturstudie och en fallstudie som genomförs i samarbete med Tekniska verken i Linköping AB och Tekniska verken Nät, där tre fall av varierande storlek undersöks:• En elbilsladdningstation, med ett toppeffektbehov på upp till 1 MW.• En fördelningsstation, med ett ursprungligt toppeffektbehov på nästan 3 MW.• Köpt effekt från det regionala nätet, där toppeffektbehovet uppgår till nästan 152 MW. Vid dimensionering av ett batterilagringssytem från den årliga effektkurvan måste en effektbegränsning sättas. Därefter kan den överstigande effektopplasten, den längsta tiden effektbegränsningen överstigs och den högsta överstigande energin tas fram, för att etablera kurvans karaktäristik. En undersökning gjordes om ett batterilager kunde användas för att möta effektbehovet då en effektbegränsning införs till den årliga effektkurvan. Batterier lagrar elektrisk energi i formen av elektrokemisk energi för att sedan transformera tillbaka det till elektrisk energi då det finns ett behov. Effektiviteten av transformeringen varierar beroende på den kemiska blandningen som batteriet är uppbyggt av. Det så kallade litiumjonbatteriet är det mest använda idag och nyttjar litium i formen av joner tillsammans med en metallisk katod och en anod av kol. Katod och anod kan variera vilket medför en förändrad karaktäristik och betyder alltså att det finns olika sorters litiumjonbatterier. Den specifika litiumjärnfosfat (LFP) blandningen ansågs mest användbar i elnätsapplikationer. Detta på grund av sin höga energidensitet, lättillgängliga material, generella säkerhet, teknikens mognad och mängden urladdningscyklar den kan hantera. Ett batterilagringssytem kunde då modellerades utefter LFP-batterikemin i kombination med den årliga effektkurvan för varje fall. Resultatet därifrån visade att en korttidsvariabilietet av effektbehovet var en framgångsfaktor vid implementeringen av ett batterilagringssystem. Detta då det tillåter för ett batterilagringsystem att återladdas oftare och en lägre minimal energikapacitet kan dimensioneras vilket gör den mer optimal. Vid undersökning av investeringskostnaden upptäcktes en svaghet i litteraturen vid jämförandet av kostnadsuppskattningar. Uppskattningen kunde variera beroende på publiceringsdatum, val av batterikemi, landets skatter och bidrag. Därav valdes en kostnadsuppskattning från den svenska stamnätsägaren, Svenska Kraftnät på 5–6 MSEK/MWh utifrån en rapport publicerat sent i 2022 som mest relevant. Utifrån kostnadsuppskattningen kunde en beräkning av investeringskostnad och ytterligare ekonomiska gynnsamheter relevanta för varje fall undersökas (såsom en jämförelse mot konventionell nätförstärkning eller sänkt abonnemangskostnad). Den generella slutsatsen som drogs var däremot att investeringskostnaden för ett batterilagringssystem var för dyrt för att vara ekonomiskt genomförbart. Det var dessutom inga betydande ekonomiska gynnsamheter som kunde ändra på det då batterilagringssystemet endast användes till att sänka toppeffektlaster. En avslutande generalisering och diskussion av drivkrafter och barriärer framgav att applicerbarheten av ett batterilagringsystem kunde definieras utifrån den identifierade karaktäristiken av den årliga effektkurvan. Dessutom framkom det att investeringskostnaden i varje fall var för hög då batterilagringssystemet endast nyttjades som nätförstärkning. Hursomhelst kan ett batterilagringssystem bidra till ytterligare fördelar i elnätets stabilitet. Elnätsägaren kan inte äga ett batterilagringssystem och använda det på effektreservmarknaden som annars kunde bidra till batterilagringssystemets ekonomiska genomförbarhet. Det slutliga målet av arbetet har varit att ge en bredare förståelse för batterilagring som en del av elnätet. Detta genom att ta reda på när och var det är applicerbart och hur man kan utvärdera dess användning.

Indiana University-Purdue University Indianapolis (IUPUI) / There is a strong urge for advanced diagnosis method, especially in high power battery packs and high energy density cell design applications, such as electric vehicle (EV) and hybrid electric vehicle segment, due to safety concerns. Accurate and robust diagnosis methods are required in order to optimize battery charge utilization and improve EV range. Battery faults cause significant model parameter variation affecting battery internal states and output. This work is focused on developing diagnosis method to reliably detect various faults inside lithium-ion cell using electrochemical model based observer and fuzzy logic algorithm, which is implementable in real-time. The internal states and outputs from battery plant model were compared against those from the electrochemical model based observer to generate the residuals. These residuals and states were further used in a fuzzy logic based residual evaluation algorithm in order to detect the battery faults. Simulation results show that the proposed methodology is able to detect various fault types including overcharge, over-discharge and aged battery quickly and reliably, thus providing an effective and accurate way of diagnosing li-ion battery faults.