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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.
11

Estudo eletroquímico e estrutural do eletrodo de hidróxido de níquel modificado com cério para estabilização da fase α-Ni(OH0)2 / Electrochemical and structural study of the electrode of hydroxide of nickel modified with cerium for stabilization of the phase 945;-Ni(OH)2

Gislaine Maria Bragagnolo 25 November 2005 (has links)
O Ni(OH)2 é amplamente utilizado como principal componente ativo do eletrodo positivo na maior parte das baterias secundárias como: Ni/Cd, Ni/Zn, Ni/Fe, Ni/H2 e, recentemente na pilhas de Ni/MH. Estes acumuladores possuem variadas aplicações como: satélites geoestacionários, alimetação de recarga de computadores, aparelhos portáteis. Apesar do eletrodo de Ni(OH)2 possuir boa durabilidade, após vários ciclos de oxidação/redução ocorre a transformação do par redox α-Ni(OH)2/β-NiOOH para β-Ni(OH)2/γ-NiOOH o qual ocasiona uma diminuição na capacidade de carga. Por essa razão, é necessário o estudo do efeito de aditivos para estabilização da capacidade de carga no eletrodo. Neste trabalho, hidróxido de cério foi utilizado como aditivo para estabilizar o α-Ni(OH)2. Os resultados obtidos mostram que os íons cério são incorporados no eletrodo estabilizando a fase α-Ni(OH)2 e com isso aumentando a capacidade de carga do mesmo. Nas análises de espectroscopia no IV e Raman foi possível verificar modificações estruturais causadas pela presença de íons Ce3+ na estrutura, principalmente, a partir de 21,33% em mol do aditivo. Nos estudos de ciclagens sucessivas a fase α-Ni(OH)2 foi estabilizada na presença de 21,33% em mol do aditivo uma vez que a capacidade de carga do eletrodo manteve-se constante ao longo de 90 ciclos de oxidação/redução. / Ni(OH)2 is widely used as main active component for positive electrodes for secondary batteries such as Ni/Cd, Ni/Zn, Ni/Fe, Ni/H2 and recently in cell of Ni/MH. These accumulators show certain characteristics and they have several applications, such as: geostationary satellites, recharge feeding of computers, portable devices. Although the electrode of hydroxide of nickel have a good durability, after several oxidaction/reduction cycles, the material suffer modification from α-Ni(OH)2/β-NiOOH to β-Ni(OH)2/γ-NiOOH, decreasing its charge capacity. For this reason, it is necessary to study the role played by some additives for stabilization of charge capacity the electrode. Our results show that the cerium ions are incorporate in the electrode, stabilizing the α-Ni(OH)2 and therefore increasing charge capacity of the electrode. In the IV and Raman Spectroscopy analyses it was possible to verify structural modification caused by the presence of Ce3+ ions in the structure, mainly for 21,33% in mol of the additive. Potentiodynamic cycling experiments have shown that the phase α-Ni(OH)2 was stabilized with 21,33% of additive and the charge capacity of the electrode remains constant throughout 90 oxidation/reduction cycles.
12

Studium vlastností katodového materiálu pro Li-ion články v závislosti na struktuře aktivní vrstvy / Study of the properties of a cathode material for Li-ion cells depending on the structure of the active layer

Kršňák, Jiří January 2014 (has links)
This article deals with properties of cathode material of lithium-ion cells study in term of active layer dependence. Aim of the work is to get familiar with problematics of cathode material production and diagnostics and to compare different active layer production methods. The opening of the work is concentrating on rechargeable batteries, mainly lithium-ion batteries and their electrode materials. Practical part is describing method of cathode material production and its characteristics.
13

Development of deterioration diagnostic methods for secondary batteries used in industrial applications by means of artificial intelligence / 人工知能を用いた産業用二次電池の劣化診断法開発 / ジンコウ チノウ オ モチイタ サンギョウヨウ ニジ デンチ ノ レッカ シンダンホウ カイハツ

Minella Bezha 22 March 2020 (has links)
蓄電池は携帯機器,電気自動車をはじめ,自然エネルギー有効利用に至るまで広範囲に利用され,その重要性はますます高まっている。これら機器の使用時間や特性は蓄電池の特性に大きく依存することから,電池自体の特性改善に加え,劣化を診断してより効率的に電池を運用することが求められている。本論文は,非線形情報処理を得意とする人工知能を用いた2次電池の劣化診断法を開発し,エネルギーの有効利用に資する技術を確立した。機器動作時の電池電圧・電流波形と電池劣化特性との関連性を,人工知能を用い学習することにより,機器稼働時に電池の劣化を診断することができる。なお,この関連性は非線形で複雑であるが,非線形分析を得意とする人工知能は劣化診断に適している。学習には時間を要するものの,診断は短時間になし得ることから,提案法は稼働時劣化診断に適している。本論文では,この特徴を生かし,電池の等価回路(ECM)を導出し,充電率(SOC),容量維持率(SOH)を推定している。また,本論文では現在産業応用分野で用いられている,リチウムイオン電池,ニッケル水素電池,鉛蓄電池を対象とし,提案法はあらゆる電池使用機器に応用可能である。また,提案法を電池状態監視装置(BMU)や,マイコンなどを用いた組み込みシステムに応用可能とし,実証している。以上のことから,本論文は,新たな蓄電池の劣化診断法の確立し,その有効性を確認している。 / The importance of rechargeable batteries nowadays is increasing from the portable electronic devices and solar energy industry up to the development of new EV models. The rechargeable batteries have a crucial role in the storage system, mostly in mobile applications and transportation, because the period of its usage and the flexibility of the function are determined by the battery. Due to the black box approach of the ANN it is possible to connect the complex physical phenomenon with a specific physical meaning expressed with a nonlinear logic between inputs and output. Using specific input data to relate with the desired output, makes possible to create a pattern connection with input and output. This ability helps to estimate in real time the desired outputs, behaviors, phenomes and at the same time it can be used as a real time diagnosis method. / 博士(工学) / Doctor of Philosophy in Engineering / 同志社大学 / Doshisha University
14

Caractérisation et modélisation de composants de stockage électrochimique et électrostatique / Characterization and modeling of electrochemical and electrostatic storage components

Devillers, Nathalie 29 November 2012 (has links)
Dans le domaine aéronautique, l'optimisation du rendement énergétique global, la réduction des masses embarquées et la nécessité de répondre aux besoins énergétiques croissants conduisent à développer de nouvelles technologies et méthodes pour générer l'énergie électrique à bord, pour la distribuer, la convertir et la stocker. Dans cette thèse, des éléments de stockage de l'énergie électrique sont caractérisés dans l'optique d'être modélisés. Parmi les différents systèmes de stockage, présentés dans un état de l'art préliminaire, sont retenus les supercondensateurs et les accumulateurs électrochimiques Lithium-ion polymère, considérés respectivement comme des sources de puissance et d'énergie, à l'échelle de l'application. Ces moyens de stockage sont caractérisés par chronopotentiométrie à courant constant et par spectrométrie d'impédance électrochimique. Les essais sont éffectués dans des conditions expérimentales, définissant le domaine de validités des modèles, en cohérence avec les contraintes de l'application finale. Différents modèles sont alors développés en fonction de leur utilisation : des modèles simples, fonctionnels et suffisants pour la gestion globale d'énergie et des modèles dynamiques, comportementaux et nécessaires pour l'analyse de la qualité du réseau. Ils sont ensuite validés sur des profils de mission. Pour disposer d'un système de stockage performant et en adéquation avec les besoins énergétiques de l'aéronef, une méthode de dimensionnement est proposée, associant des composants de stockage complémentaires. Un gestion fréquentielle des sources est mise en oeuvre de manière à minimiser la masse du système de stockage. / In aeronautics, the optimization of the global energetic efficiency, the reduction of the embedded weight and the need to meet the growing energetic requirements lead to develop new technologies and methods to generate electrical energy, to distribute it, to convert it and to store it aboard. In this thesis, electrical energy storage systems are characterized with a view to be modeled. Among varied storage systems, presented in an introductory state of the art, ultracapacitors and Lithium-ion polymer secondary batteries are studied. These components are considered respectively as power and energy sources, in regards to the application scale. These storage systems are characterized by chronopotentiometry at constant current and by electrochemical impedance spectrometry. Tests are carried out in experimental conditions which define the validity area of modeling, in relation with the application constraints. Different models are developed according to their future use : simple models, which are functional and sufficient for the global energy management, and dynamics models, which are behavioral and necessary for the analysis of the network quality. Then, they validated thanks to mission profiles. Finally, to dispose of an efficient storage system that meets the energetic requirements of the aircraft, a sizing method is suggested by combining complementary storage systems. An energy management based on frequency approach is implemented in order to minimize the storage system weight.

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