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Causes of Premature Capacity Loss of Lead-Acid Accumulators Operating in PSoC Mode in Hybrid Electric Vehicles
Bilko, Radek ; Jareš, Petr (referee) ; Dostál, Zdeněk (referee) ; Bača, Petr (advisor)
This thesis is completion of whole stage of researches and it is a result of existing need of increase efficiency, utilization rate and service life of lead acid batteries VRLA planned for utilization in hybrid electric vehicles in mode of partial state-of-charge PSoC. During the application of mode PSoC at lead acid battery occurs irreversible sulfation of negative electrodes and thus to loss their charging capability. This phenomenon, according to the latest trend called PCL3, isn´t connected with subsequently referred effects PCL1, PCL2, show up on positive electrodes. Result of this thesis is finding a new types of additives, determine their optimum amount and size in such a way that innovated composition of negative active materials be able to resist sulfation of negative electrode during operation in mode PSoC. Part of the effort to clarify actions ongoing on negative active material and causes non-returnable sulfation electrodes is also monitoring of structural changes electrode active material by using environmental scanning electron microscope, which helped to clarify processes related with loss of capacity in mode PSoC. Special attention during reserches was focused on study of the properties contact layers between collector and electrodes active material and itself active materials lead-acid battery druring exploitation. There were gain new information about influence repeated cycling of (charging, discharging) the critical area of the electrodes. Measurements was carried out on specially prepared experimental electrodes DC Difference Method, this enabled obtain data in situ.
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Expanded Graphite as Negative Electrode for Lithium-Ion Batteries
Bibik, Maria ; Máca, Josef (referee) ; Libich, Jiří (advisor)
This bachelor’s thesis examines the issues related to the lithium-ion batteries and describes their basic elements, operating principle and technological parameters. It is focused on studying different materials for the negative electrode (anode) that is based on natural graphite. It describes in detail expanded natural graphite materials which are used as an active electrode material. This thesis describes experiments of the impact of the pressure force on power and capacity characteristics of the negative electrode in aprotic system of li-ion batteries.
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Microscopic Observations of Active Mass Structures of the Negative Electrode of a Lead-Acid Battery
Zimáková, Jana ; Dostál, Zdeněk (referee) ; Kohout,, Jan (referee) ; Bača, Petr (advisor)
This doctoral dissertation deals with the study of the effect of additives on the properties of the negative electrode of a lead-acid battery. The work focuses on the investigation of the additive/base material interface for the negative electrode (so-called active mass) using atomic force microscopy (AFM). A lead sheet was used as the base material, on which the given additive was applied. The effects of carbon, TiO2, glass fibers and Indulin AT were specifically investigated. The negative electrode was cycled by a potentiostat in a defined manner and the morphology of the electrode surface was continuously scanned by AFM. This created a time sequence of images on which events on the surface of the electrode during its charging/discharging were captured. These records serve to better understand the effect of additives on the resulting properties of constructed lead-acid cells, specifically on the ability to form or dissolve PbSO4 crystals, which are formed during cell discharge and are responsible for the decrease in total capacity - gradual surface sulfation.
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Infuence of Technological Parameters on Electrochemical Properties of Negative Electrode in Lithium-ion Cell
Kaňa, Michal ; Máca, Josef (referee) ; Libich, Jiří (advisor)
This diploma thesis deals with lithium-ion batteries. It is focused on negative electrode on grafit based. The goal of this thesis is to show the problematics of lithium-ion batteries together with possibilities for improvement of their basic parametres as capacity and current elektricity loadability. The first part is focused on the description of functionality of lithiumion battery. The second part is practical and it is focused on production of negative electrodes from natural graphite 280H which has different thickness and compression pressure. The third part describes preparation of negative electrodes from natural graphite 280H and also includes results of measurement. In the last part are different types of negative electrodes from natural graphite 280H compared and evaluated including the determination of conclusions. This comparison and evaluation based on obtained data.
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Negative electrode materials for lithium-ion batteries
Šikuda, Milan ; Vondrák, Jiří (referee) ; Libich, Jiří (advisor)
This theses deal with a study of basic functional principles of cells. It is focused on carbon materials, which are the basic for negative electrode masses of lithium-ion accumulators. The aim of this work is understanding principle lithium-ion accumulator, get an overview about the most widespread materials currently using for negative electrode materials with measuring their characteristics. Then compare characteristics of carbon materials with alternatives materials for negative electrode on the base of silicon. First part of the work is devoted of principle functionality lithium-ion accumulators together with description of galvanostatics and potentiostatics measuring methods. Practical part deals with preparation and measuring negative electrode masses characteristics.
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Influence of flame retardant on negative electrodes in lithium - ion accumulator
Buchta, Martin ; Libich, Jiří (referee) ; Máca, Josef (advisor)
This diploma thesis deals with problematics of electrochemical power sources with focus on lithium accumulators, their construction and functioning priciple. It also discusses the safety of li-ion batteries with respect to their flammability. In addition, the flame retarders, which help to lower the flammability, are listed. The thesis describes Cyclic Voltammetry and Galvanostatic Cycling with Potencial which are lithium-ion cell measuring methods. In the last part, the influence of various flame retarders on negative electrode is compared based on the conducted tests.
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Testing of a Prototype Device Using Electrochemical Impedance Spectroscopy (EIS)
Zsigmond, András ; Jaššo, Kamil (referee) ; Libich, Jiří (advisor)
.Tato diplomová práce se zabývá elektrochemickými procesy v lítium-iontových bateriích. Pro charakterizaci různých elektrochemických procesů se používá metoda nazývaná elektrochemická impedanční spektroskopie (EIS). V prvních kapitolách jsou popsány různé typy baterií a jejich rozdíly. Práce také obsahuje popis experimentálního zařízení používaného pro EIS. Součástí práce je také porovnání experimentálního zařízení a zařízení od společnosti BioLogic Science Instruments.
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Lithium-ion battery: Negative electrode materials based on graphite
Vencelides, Lukáš ; Máca, Josef (referee) ; Libich, Jiří (advisor)
This bachelor‘s thesis deals with the isuess related to the lithium-ion batteries. The history of development of lithium-ion batteries, current commercially available and developed types are described in the thesis. The thesis deals in detail with the description of the characteristics and operating principle of lithium-ion accumulators with emphasis on negative electrode and negative electrode materials. The goal of the thesis is technological and electrochemical characterization of graphite negative electrode materials. Two types of natural graphite are used in the thesis, both are potenti-galvanistically analyzed from the point of view of capacitance and current characteristics.
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Lithium-ion cell: Treatment of Natural Graphite by Lithiation Method
Bílek, Lukáš ; Kazda, Tomáš (referee) ; Libich, Jiří (advisor)
This bachelor thesis deals with the issue of lithium-ion accumulators. The thesis focuses on the negative electrode of lithium-ion accumulator made of natural graphite. In the theoretical part the thesis focuses on the characteristics, the operating principle and the use of lithium-ion accumulators. Negative electrode materials are also analyzed. The main topic of the thesis is the use of lithiation method which suppresses irreversible capacity losses with the improvement of the capacitance and current characteristics of the battery.
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