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Lighting and lighting systems for stand-alone applications
Čejka, Lukáš ; Škoda, Jan (referee) ; Baxant, Petr (advisor)
This bachelor's thesis deals with the issue of lighting systems for stand-alone applications. These systems are independent of the electrical connection and they are powered by batteries. Batteries are charged by independent sources. The work is more focused on an autonomous lighting system that uses a solar panel. It mentions the main components of the system. Furthermore, in this work, we can find types of stand-alone lighting applications, their possibilities, problems, advantages and disadvantages, economic balance and also outline other possible solutions.
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Lead-acid baterry charger with automatic cycle
Moravec, Pavel ; Friedl, Martin (referee) ; Steinbauer, Miloslav (advisor)
The lead-acid batteries are still important and very often used type of battery even in 21st century. This project is focused on development of charger, which provides fast, but save charging of batteries with respect to maximum life time and reliability. The developed system uses constant current charging and constant voltage charging methods. It's specialized in charging batteries with liquid or gel electrolyte and traction types of batteries, which works with 12 V value of voltage. It's able to charge safely the deeply discharged batteries and when battery is unpluged for a long time, it can keep its capacity at maximum level too. The charger can choose optimal charging process according to the discharged level of battery. Each charging phase is interpreted by light signals and the achievable charging current is 20 A.
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Examination of temperature changes in lead-acid battery system
Starý, Viktor ; Křivík, Petr (referee) ; Bača, Petr (advisor)
In the automobile industry is always more often talking about hybrid electric vehicles at the present. Functioning of these hybrid automobiles is provided by source of energy. This source is represented by accumulator. When accumulator is working we can see temperature changes. This project is dealing with used types of accumulators for hybrid electric vehicles. In the second phase is dealing with enquiring of temperature changes during different modes of operating.
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Research of thermal effects in lead-acid batteries
Vrba, Marek ; Abraham, Pavel (referee) ; Neoral, Jiří (advisor)
Based on the Czech and foreign literature, this work introduces us to the history, the dividing types of electrochemical cells, specifically deals with the lead-acid battery. The lead-acid battery principle is described and its behavior during charging and discharging. Another topic is the design and distribution. The basic division is the lead-acid accumulator batteries with electrodes submerged and maintenance-free batteries so-called "VRLA", which is gradually coming into force and function of classical battery electrodes are submerged in more demanding applications. Currently, VRLA batteries are used for PSOC system in hybrid vehicles. The practical part of this work deals with PSOC regime that is applied to the experimental cells with electrodes with different admixtures. The results of the influence of admixtures on the durability of articles in PSOC system are summarized at the end of this work.
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Optimization of use properties Lead-Acid batteries
Lábus, Radek ; Dostál, Zdeněk (referee) ; Jareš, Petr (referee) ; Křivík, Petr (advisor)
This thesis focuses on the limitations of degradation mechanisms of Lead-Acid batteries, which significantly contributes unequal distribution of current (and therefore internal resistance, charge passed and power loss) on the surface of the electrodes of Lead-Acid battery. The unevenness of distribution of these parameters significantly influences the distribution of current tabs on the electrodes. In this work it was developed realistic model of Lead-Acid battery cell with plate electrodes with different variants of the distribution of current tabs. Measured results obtained in this model were compared with the results found out from the mathematical simulations. Through these simulations, it was possible to take a look deeply into the processes and changes in the electrodes of Lead-Acid batteries during discharge. Goal of this work was for predefined variants of positioning of the current tabs to simulate distribution of current, internal resistance, charge passed and power loss during discharge. Another goal was to compare the different variants and to find the optimal variant of current tabs positioning based on minimizing of unevenness of examined variables distribution.
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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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Optimalization of pulse charging mode of lead-acid battery
Sygeryč, Daniel ; Vaněk, Jiří (referee) ; Křivík, Petr (advisor)
This thesis deals with pulse charging lead acid batteries. The theoretical part provides the basic electrochemical reactions that take place in the lead pack, then this section discusses important parameters of lead-acid battery, its structure and distribution of the various types depending on the application. The next section describes the theory of charging lead-acid battery. The practical part deals with constructing experimental cells, which are then tested. The subject of the experimental execution and optimization of pulse charging modes in order to find a suitable pulse mode, which reduces the duration of charging, while significantly shorten the life of lead-acid battery.
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Temperature changes during pulse charging of lead-acid accumulator
Přikryl, Kamil ; Bača, Petr (referee) ; Křivík, Petr (advisor)
This master's thesis deals with the issue of lead-acid batteries, their charging methods and issue of thermal processes in lead-acid batteries. The thesis is divided into three main parts. The first section describes the theoretical knowledge of lead-acid batteries, such as history of lead-acid battery, structure, principle of operation, methods of charging and thermal processes taking place in the lead-acid battery. The second part describes in detail the production of experimental electrodes. The last section describes the automatic data logger for measuring and experiments, which were focused on pulse charging method with variable duty cycle pulses.
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Wind power generation and energy accumulation possibilities
Krbal, Michal ; Mastný, Petr (referee) ; Drápela, Jiří (advisor)
The goal of this bachelor’s thesis is to inform about conditions of running and the character of running of the wind power plants and about the suitable storage systems for the possibilities of time invariableness of power supply. For these reasons is immediately in the first chapter of the thesis described state of using wind power plants in The Czech republic and other countries in Europe which produce electric power. Description of individual functional parts is important mainly from the point of electrician conversion of kinetic energy of wind to electric energy with help of the electric power generator with the highest efficiency and without need for maintenance. It is necessary to know those functional parts of the power wind to be able to design appropriate storage system. The output electric power is very variable at time, mainly output voltage, because wind energy is variable too. The characteristics of the wind power plants as output voltage, frequency and their switching graded at time have to in accordance with requirements of the electricity supply systems not to disturb the stability or even collapse of the electricity supply system which would lead to serious economic consequences. These predicaments can be prevented with precise meteorological forecast or by using the acceptable storage system with small acquisition and operating costs, requirements to safeness and long service life, low weight and high efficiency of conversion of energy. The storage systems are classified into centralized and decentralizing systems with requirements to dynamic running and running time. To fulfil these conditions it is essential to choose acceptable and accessible locations with year lasting qualities of wind, which are being checked in advance using measurement and mathematical calculations.
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