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Výzkum interkalačních vlastností elektrodových materiálů založených na expandovaném grafitu / Study of intercalation properties of electrode materials based on expanded graphiteVencelides, Lukáš January 2020 (has links)
The diploma thesis deals with the issue of electrochemical cells and deals in detail with lithium-ion batteries. The thesis describes the history of development of lithium-ion batteries, basic information about lithium and basic types of electrochemical cells. The work is devoted in detail to the description of characteristics and operating principle of lithium-ion batteries with emphasis on the negative electrode and negative electrode materials. Of the negative electrode materials, both the most widely used material graphite and modern materials with a great potential for the future are described. In the measurement methods the work describes methods CV, GCPL and EIS. Great emphasis is placed on the explanation of the principle of the function of electrochemical impedance spectroscopy and its application in measurement of electrochemical properties of materials used in lithium-ion batteries. There is also described the procedure of calculation of diffusion coefficients using the results of electrochemical impedance spectroscopy. In the practical part, two methods are used to calculate the diffusion coefficients of lithium ions into the negative electrode made of expanded flake graphite using the results of a series of electrochemical measurements.
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Studie materiálů pro Li-ion akumulátory pomocí elektronové mikroskopie / Study of materials for the Li-ion batteries by electron microscopyHujňák, Jan January 2020 (has links)
This work deals with problems of lithium-ion batteries. In the theoretical part are described electrochemical sources in general and their division. The main representatives of individual types of electrochemical sources are described in more detail. In the next part the thesis focuses specifically on lithium-ion accumulators, their history, electrochemical reactions taking place inside and materials of individual parts of which the accumulator consists. Next part focuses on electron microscopy and its division into scanning and transmission. Basic parts and the principle of operation are described. The practical part is focused on creating a small cell for examination under an electron microscope.
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Stanovení nejvhodnějšího poměru katodových materiálů pro systém lithium-síra / Determination of the most suitable ratio of cathode materials for the lithium-sulfur battery systemBenešová, Petra January 2021 (has links)
This master's thesis deals with a topic of determination of the most suitable ratio of cathode materials for the lithium-sulfur systems. The first two chapters provide a general introduction to the topic of electrochemical energy sources and present the commonly used primary and secondary battery systems with emphasis on their characteristics and applications. The core of the theoretical part is dedicated to lithium-ion and lithium-sulfur batteries, their working principles along with the benefits or drawbacks related to the particular systems, and widely used materials. The experimental part briefly comments on determining the suitable electrode paste preparation method, the subsequent main part is focused on evaluation of electrochemical performance of cells using different ratios of cathode materials. Five samples of cathode materials were prepared, where the sulfur ratio is in range from 64 to 88 wt. %. Finally, the comparison of all prepared ratios in terms of their electrochemical properties is provided.
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Trakční pohon elektromobilu napájený vodíkovým palivovým článkem / Electrocar traction drive supplied with the hydrogen fuel cellPokálený, Jan January 2008 (has links)
The topic of this diploma thesis is a traction drive of electrocar with fuel cell. The drive is supplied with hydrogen fuel cell with power of 2 kW. The traction drive consists of the three-phase DC/AC converter and the asynchronous machine. The main part of this work is a creation of the mathematical model of the traction drive in program Matlab–Simulink.
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Vývoj ovládacího programového prostředí pro autonomní fotovoltaický systém / Development control programme for autonomous fotovoltaic systemJanáč, Stanislav January 2009 (has links)
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.
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Vývoj fukčních bloků pro autonomní fotovoltaický systém / Functional blocks for the development of autonomous photovoltaic systemOvesný, Karel January 2011 (has links)
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.
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Regulátor otáček pro střídavé motory / Controler for brushless motorsZdařil, Tomáš January 2012 (has links)
The goal of the thesis was to design and create one-way speed controler for brushless DC motors, that is used in air modeling. The circuit is controlled by the Atmel AVR. As power unit for motor is used Li–pol accumulator. The controller is equipped with BEC to power the receiver and allows monitoring of current consumption and voltage on the accumulator. Measured data can be upload to a PC where they can be displayed by RegulatorPC in graphical form.
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Vliv různých typů AGM separátorů na parametry olověných akumulátorů pro hybridní elektrická vozidla / Influence of different types of AGM separators on parameters of lead-acid batteries for hybrid electric vehiclesČada, Miroslav January 2013 (has links)
The most used type of the secondary energy sources is the lead-acid accumulator today. It is also used as a propulsion in hybrid electric vehicles. Functional principle stayed same as in foundation time, only parameters are still improving. Lifetime of lead-acid accumulator is influenced by used separator. The work deals with the description of properties of lead acid separators, methods of testing and evaluation of the suitability for use.
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Cyklovací režimy olověných akumulátorů / The cycle modes of lead-acid batteriesMičák, Tomáš January 2013 (has links)
Main goal of the diploma thesis is to examine lead-acid accumulator and to study cycling modes in different setups. Theoretical part describes history, types of maintenance-free batteries, degradation mechanisms and possibilities to remove them. Practical part involves the production of electrodes and experimental cell, composition of active mass and measurement of internal resistance. Different configurations for deep cycling are researched as well. The results of the work are summarized and commented at the conclusion of the thesis.
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Zkoumání vlivu oxidu titaničitého na životnost olověných akumulátorů s aplikovaným přítlakem / Influence of titanium dioxide on the life of lead acid batteries with applied pressureŘihák, Pavel January 2013 (has links)
Hybrid electric vehicles use lead acid batteries operating under partial charge. Battery life of these batteries is dependent on the speed of development of lead sulphate (PbSO4) to the negative electrodes. Different admixtures are affected battery life. This work deals with the influence of titanium dioxide on the negative active material in lead battery. Mainly devoted to the influence of the applied pressure.
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