Made available in DSpace on 2014-10-09T12:35:00Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T13:59:32Z (GMT). No. of bitstreams: 0 / Tese (Doutoramento) / IPEN/T / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP

Made available in DSpace on 2014-10-09T12:35:00Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T13:59:32Z (GMT). No. of bitstreams: 0 / Este trabalho apresenta a contribuição obtida no desenvolvimento de um Gerador de Eletricidade Híbrido (HYBRIDGEN), com tecnologia nacional, focado nos sistemas de terceira geração de energia elétrica híbrido, composto por um módulo de células a combustível tipo PEMFC, associado a um acumulador chumbo ácido. Mostra-se também a sua capacidade de operar em modo contínuo, carga com demanda variável e fator de carga inferior a 50%. Foram abordados quatro temas principais. O primeiro refere-se a um estudo para a melhoria da eficácia na conversão de energia em corrente contínua (cc), ao regular o potencial de saída do conversor cc-cc. A energia é proveniente do módulo de célula a combustível de 1 kWe, equipado com sistema térmico de refrigeração e sistema de alimentação de gases, aqui denominados MCC1. Para tal, foi construído o modelo matemático do sistema conversor de corrente contínua (sistema conversor cc-cc), com solução suportada em equações diferenciais algébricas, ensaios no MCC1, bem como em simulação computacional no programa MATLAB7®. O segundo tema refere-se ao desenvolvimento do projeto e montagem do protótipo do HYBRIDGEN devido à inexistência no mercado brasileiro de um equipamento com as características necessárias tanto para a pesquisa, quanto para uso comercial. Desenvolveu-se uma placa controladora para o acumulador (PCC), os esquemas elétricos, os barramentos e o sistema de relés. Também foi utilizado o MCC1 em desenvolvimento pelo IPEN e ELECTROCELL® com tecnologia 100% nacional. O HYBRIDGEN foi instalado em um sistema móvel. O terceiro tema refere-se à análise de estabilidade do modelo matemático do sistema conversor cc-cc. Utilizou-se de quatro testes de estabilidade, sendo: 1 - pela Resposta em Frequência ao utilizar o Teorema do Mapeamento, de Nyquist; 2 - Lugar das Raízes, de Nyquist; 3 - função de teste Degrau, em pontos de operação e, 4 - função de teste Impulso, em pontos de operação. Por fim, apresentaram-se os resultados dos ensaios de potencial e corrente de uma célula a combustível unitária de 25 cm2, do MCC1, e do HYBRIDGEN. No desenvolvimento dos primeiros testes o MCC1 atingiu 704,55 We, (potência considerada condição predominante de operação). A seguir, demonstrou-se a capacidade do HYBRIDGEN para simultaneamente: alimentar cargas em corrente contínua; carregar o acumulador de 45 Ah; alimentar o inversor de 2 kWe e o autotransformador, para fornecer energia a equipamentos em 12Vcc, 127 Vac e 220Vac, 60 Hz, todos num total de 819,52 We. Esses resultados foram obtidos mesmo com limitações na refrigeração ventilada do MCC1, observadas no decorrer dos testes. Assim, o HYBRIDGEN se mostrou viável tecnicamente, e com grande potencial de uso. / Tese (Doutoramento) / IPEN/T / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP

This thesis deals with the problematic of lead acid batteries for HEVs. It starts with classification of electrochemical cells then proceeds to focus on lead acid batteries, mainly because they are the most used source of electrical power in automotive industry. The practical part of the work describes the process of manufacturing the electrode system used in the later parts. The experimental part is focused on the behaviour of the cells under conditions that appear in hybrid electric vehicles. The effect of aditives in active matter of the negative electrode on the parameters of the cells is observed, such as voltage, capacity and operating life

This master's thesis is focused on in situ observation of the negative electrode of the lead acid accumulator using atomic force microscopy AFM. Discussed topics are lead acid accumulator, atomic force microscopy, cyclic voltammetry and current knowledge of the in situ observation of the lead acid accumulator using AFM. The main task of this project is assembling the experimental cells, make in situ observation of the negative electrode surface of the lead acid accumulator. In the end evaluate if this method is suitable for the lead acid battery observation.

This thesis deals with lead-acid battery, its parameters and temperature behaviour of this electro-chemical source of power. In the theory section, types of batteries are presented, followed by their primary parameters and electro-chemical reactions, which take part in battery cells. This section also contains information about charging stages, detailed description of each battery part, used materials, construction of the battery and degradation processes caused by battery operation. The practictal section of this thesis offers a measurement scheme for automated measuring workstation. Furthermore, the practical section presents results of measurements on parameters of chosen lead-acid battery types, it also contains long-term deep battery cycling and measurements under elevated temperatures. Detailed comparison of measurements results and datasheet values is included. Conclusion sums up parameters of chosen lead-acid battery types and their feasibility for further usage in power backuping.

The thesis briefly discusses the issue of electrochemical power sources, especially with a focus on lead-acid batteries operating in modes that are typical of hybrid electric vehicles. The theoretical part of the thesis should be a good basis for the subsequent practical part, in which several experimental electrodes and their parameters will be performed and evaluated. The output of the practical part will be conclusions regarding the influence of different variants of modified carbon used as an additive in the active material of the negative electrode on the capacity and life of cells

This presented work deals with the development of an automated station for the measuring of experimental cells of the Lead Acid Battery. The principle is to design a measuring station and make programs for cycling of cells in standard and PSoC modes.

The project considers realization system, which allows us to test six different operation modes on lifetime of accumulators. The system will be connected to computer, that will perform measurement of current and voltage and switch betwen charge and discharge modes. The measured values will be recorded in certain time intervals to computer memory. After some time these measured data will be analised and the most optimal operational mode will be set.

The project considers realization system, which will allow us to test six different operation modes on lifetime accumulators. The system will link to computer, which will execute measurement current and tension and switch betwencharging and discharging modes. The measured values will record in someone time intervals in to computer memory. After someone time will analise these measured valuer and will provide optional operation mode.

Tato diplomová práce se zabývá návrhem a realizací regulátoru pro použití v solárním systému s větším počtem olověných akumulátorů. Takový regulátor umožňuje nezávislé připojení a řízení nabíjení většího počtu akumulátorů různého stáří a parametrů. To je v kontrastu s řešeními obsahujícími jedno připojení pro více baterií připojených paralelně, kde se míchání baterií různého druhu a stáří nedoporučuje. Tento regulátor nabízí vysokou škálovatelnost skladování energie v solárním systému. Umožňuje také používat starší baterie s novými, místo nutnosti staré baterie nahradit, když jejich kapacita klesne pod požadovanou úroveň. V této práci jsou podrobně popsány požadavky, návrh hardwaru a softwaru a implementace regulátoru s nominálním výstupním proudem 20A pro pět 12V olověných baterií. Práce popisuje také další funkce, stejně jako alternativní návrhy a algoritmy. Důležitá část práce se zabývá designem spínačů pro velké proudy, ochrany proti zkratu a obvodů pro měření stejnosměrného proudu. Správná funkčnost regulátoru byla ověřena měřením.