Esta dissertação tem por objetivo reportar dados relativos às características elétricas e microestruturais de eletrodos aplicadas em dispositivos armazenadores de energia, especificamente supercapacitores constituídos por eletrodos de carvão ativado. Os parâmetros elétricos estudados foram a resistência em série equivalente obtida pelo método da interrupção de corrente (ESR(Inst)) (sendo que a sigla ESR é oriunda do termo inglês Equivalent Series Resistance), a resistência em paralelo equivalente (EPR(Dep)) obtida pelo método do valor dependente (sendo que a sigla EPR é oriunda do termo inglês Equivalent Parallel Resistance) e a capacitância (C(DC)) obtida pelo método da corrente contínua (sendo que a sigla DC oriunda do termo inglês Direct Current). Tais parâmetros foram escolhidos devido ao impacto que causam no tempo de vida útil, na capacidade de armazenamento de cargas elétricas, na velocidade de carga e descarga, na perda por efeito termoiônico nos processos de carga e descarga e na perda de cargas armazenadas devido à autodescarga em supercapacitores. Os dados microestruturais reportam por meio de imagens a homogeneidade da porosidade e por meio de valores correlacionados a composição química e eventuais contaminações presentes nos eletrodos. Os dados e valores coletados possuem a intenção de servir como referência comparativa de qualidade e apontar qual parâmetro afeta mais a qualidade do supercapacitor. Para tanto foram realizados testes a fim de coletar valores de C(DC), ESR(Inst) e EPR(Dep) após a exposição de supercapacitores de 1F/5,5V a temperaturas de 50ºC, 75ºC, 100ºC e 125ºC por 672 horas, sendo os dados coletados ao inicio dos testes, à temperatura ambiente, e posteriormente a cada 168 horas. Feitos os experimentos concluiu-se que o parâmetro que sofreu maior deterioração com o acréscimo de energia térmica foi a EPR(Dep), em seguida a C(DC), que de fato pouco sofreu alteração e a ESR(Inst), em que a mudança dentro do erro de medição foi imperceptível. / This paper aims to report information on electrical and microstructural characteristics of electrodes applied at devices that store energy, specifically supercapacitors made of activated carbon electrodes. The studied electrical parameters were the equivalent series resistance obtained by the method of the instantaneous value of the voltage drop (ESR(Inst)), where the acronym ESR has the meaning Equivalent Series Resistance, the equivalent parallel resistance (EPR(Dep)) obtained by the method of dependent value, where the acronym EPR has the meaning Equivalent Parallel Resistance, and the capacitance (C(DC)) obtained by the method of direct current. These parameters were chosen because of the impact they have on lifetime, the storage capacity of electric charge, the speed of loading and unloading, the loss thermionic effect on the charge and discharge processes and loss of stored charge due to self-discharge in supercapacitors. The data given by microstructural images of the homogeneity and porosity values correlated by the chemical composition and possible contaminations present in the electrodes. The collected data and values are intended to serve as a comparative reference point and quality parameter which most affects the quality of the supercapacitor. For both tests were carried out in order to collect values of C(DC), ESR(Inst) and EPR(Dep) after supercapacitors of the 1F/5.5V are exposure at temperatures of 50, 75, 100 and 125°C for 672 hours, and the data collected at the beginning of the tests (room temperature) and subsequently every 168 hours. Made experiments it was concluded that the parameter further deterioration suffered with the increase of thermal energy is EPR(Dep), then C(DC), which in fact little changed and ESR(Inst), in which the change in the measurement error was are noticeable.

Esta dissertação tem por objetivo reportar dados relativos às características elétricas e microestruturais de eletrodos aplicadas em dispositivos armazenadores de energia, especificamente supercapacitores constituídos por eletrodos de carvão ativado. Os parâmetros elétricos estudados foram a resistência em série equivalente obtida pelo método da interrupção de corrente (ESR(Inst)) (sendo que a sigla ESR é oriunda do termo inglês Equivalent Series Resistance), a resistência em paralelo equivalente (EPR(Dep)) obtida pelo método do valor dependente (sendo que a sigla EPR é oriunda do termo inglês Equivalent Parallel Resistance) e a capacitância (C(DC)) obtida pelo método da corrente contínua (sendo que a sigla DC oriunda do termo inglês Direct Current). Tais parâmetros foram escolhidos devido ao impacto que causam no tempo de vida útil, na capacidade de armazenamento de cargas elétricas, na velocidade de carga e descarga, na perda por efeito termoiônico nos processos de carga e descarga e na perda de cargas armazenadas devido à autodescarga em supercapacitores. Os dados microestruturais reportam por meio de imagens a homogeneidade da porosidade e por meio de valores correlacionados a composição química e eventuais contaminações presentes nos eletrodos. Os dados e valores coletados possuem a intenção de servir como referência comparativa de qualidade e apontar qual parâmetro afeta mais a qualidade do supercapacitor. Para tanto foram realizados testes a fim de coletar valores de C(DC), ESR(Inst) e EPR(Dep) após a exposição de supercapacitores de 1F/5,5V a temperaturas de 50ºC, 75ºC, 100ºC e 125ºC por 672 horas, sendo os dados coletados ao inicio dos testes, à temperatura ambiente, e posteriormente a cada 168 horas. Feitos os experimentos concluiu-se que o parâmetro que sofreu maior deterioração com o acréscimo de energia térmica foi a EPR(Dep), em seguida a C(DC), que de fato pouco sofreu alteração e a ESR(Inst), em que a mudança dentro do erro de medição foi imperceptível. / This paper aims to report information on electrical and microstructural characteristics of electrodes applied at devices that store energy, specifically supercapacitors made of activated carbon electrodes. The studied electrical parameters were the equivalent series resistance obtained by the method of the instantaneous value of the voltage drop (ESR(Inst)), where the acronym ESR has the meaning Equivalent Series Resistance, the equivalent parallel resistance (EPR(Dep)) obtained by the method of dependent value, where the acronym EPR has the meaning Equivalent Parallel Resistance, and the capacitance (C(DC)) obtained by the method of direct current. These parameters were chosen because of the impact they have on lifetime, the storage capacity of electric charge, the speed of loading and unloading, the loss thermionic effect on the charge and discharge processes and loss of stored charge due to self-discharge in supercapacitors. The data given by microstructural images of the homogeneity and porosity values correlated by the chemical composition and possible contaminations present in the electrodes. The collected data and values are intended to serve as a comparative reference point and quality parameter which most affects the quality of the supercapacitor. For both tests were carried out in order to collect values of C(DC), ESR(Inst) and EPR(Dep) after supercapacitors of the 1F/5.5V are exposure at temperatures of 50, 75, 100 and 125°C for 672 hours, and the data collected at the beginning of the tests (room temperature) and subsequently every 168 hours. Made experiments it was concluded that the parameter further deterioration suffered with the increase of thermal energy is EPR(Dep), then C(DC), which in fact little changed and ESR(Inst), in which the change in the measurement error was are noticeable.

After nearly a decade of development, human-implantable sensors for detection of muscle activity have recently been demonstrated in the literature. The implantable sensors are powered and communicate wirelessly through the skin using coupled inductor coils. The focus of the present work has been the development of a new approach to modeling the inductively coupled link by using the finite element method (FEM) to simulate a three-dimensional representation of the coils and surrounding magnetic field. The validity of the simulation is tested by comparison to analytically-developed formulas for self-inductance, ac resistance and mutual inductance of the coils. Determination of these parameters is necessary for calculation of the coupling coefficient between the coils, and to fully define the lumped circuit model of the link. This 3D FEM approach is novel and attractive because it is able to encompass physical geometric parameters and material properties that have been traditionally been a challenge to determine. In particular the contribution of a ferrite-core, and the case of non-symmetrical relative coil positioning can be evaluated. / Graduate

Dans les applications de puissance, les systèmes de stockage d'énergie électrique tels que les supercondensateurs sont fortement sollicités. Compte tenu des limitations existantes lors de l'utilisation d'un seul composant, un système de stockage d'énergie électrique (module) est constitué d'une association d'éléments (cellules) permettant de s'adapter aux besoins de l'application visée. Afin d'assurer la sécurité de l'équipement et de son utilisateur, un système de gestion d'énergie, qui a pour rôle de surveiller et de contrôler continuellement les cellules, est associé au module de stockage. Le but des travaux de thèse est l'amélioration de la durée de vie des systèmes de stockage d'énergie. Cet objectif est réalisé grâce au contrôle des circuits d'équilibrage, éléments du système de gestion d'énergie, et déjà présents sur ces modules de stockage. Différentes méthodes de contrôle sont donc présentées, analysées et comparées afin d'évaluer l'état de santé des supercondensateurs surveillés. Une nouvelle approche d'équilibrage se basant sur le niveau de dégradation estimée est exposée. Elle permet d'équilibrer les vitesses de vieillissement des cellules et ainsi de prolonger la durée de vie de l'ensemble du système. Certains principes des résultats obtenus sont transposables aux batteries / Energy storage system such as supercapacitors are widely used in high power applications. However, due to single cell voltage limitation, an energy storage system (module) is often employed. It contains a chain structure of identical elements and ensures voltage adaptation to the corresponding application requirements. Energy management systems are associated to energy storage systems in order to assure user and equipment security. Their main role is to monitor and control energy storage systems elements continuously. The work presented aims to enhance the lifetime of energy storage systems. It relies on establishing balancing circuits on the terminals of the storage system elements. These control circuits are energy management system devices. Thus, various control approaches are discussed, analyzed and compared. They aim to estimate the supercapacitor's state of health. In addition, a new approach of balancing circuits is proposed. It is based on estimating the level of degradation of the elements. Thus, It allows aging speed equalization between module elements and storage system lifetime maximization. Some main results of the work could be generalized to batteries