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Influence of temperature on lead acid batteries lifetime
Kopečný, Martin ; Bača, Petr (referee) ; Neoral, Jiří (advisor)
Lead –acid batteries are the most common type of secondary cells used in automotive industry. This diploma thesis deals with the influence of temperature on their lifetime. In the preamble of this work is shortly described their history, division, construction and processes during battery operation. There are noted unfavorable phenomena which have an impact on increasing the temperature inside the battery. The first experimental part is devoted to evaluation the effects of addition on the temperature rise during charging. The second part is focused on conditions simulation in hot areas at the temperature above 30 °C and effects of this temperature on the function of lead – acid batteries.
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Health effects of ionizing and non-ionizing radiation
Gottvald, Martin ; Neoral, Jiří (referee) ; Bača, Petr (advisor)
This diploma thesis deals with electromagnetic radiation in its frequency spectrum. It also divides radiation into ionizing and non-ionizing. The principle of its effects and possible health problems from radiation exposure are also described. Hygienic limits – the maximum allowable and reference values of non-ionizing radiation are analysed too. The thesis should prove that the things of everyday need do not threaten the lives of human beings and are in compliance with the regulation No. 1/2008 Sb. on Health Protection Against Non-Ionizing Radiation. Measurement of low-frequency part is carried out with the cooperation of The National Institute of Public Health. Measurement of high-frequency part was carried out in 3 flats. The aim of this measurement was to find out the change of power density with the moving in a flat and the influence of the barriers (in this case walls).
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Thermal phenomena in lead acid batteries
Kovařík, Lukáš ; Čech, Ondřej (referee) ; Neoral, Jiří (advisor)
This thesis project solve problematic of thermal proces in lead-acid batteries. There are decribed history of lead – acid batteries, distributions of batteries, overview of construction lead – acid batteries and VRLA batteries and is decribed thermal runaway proces and basic termal process. They are listed here practical results and the measurements is concluded.
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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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Composite electrode materials for lithium-ion batteries based on LiFePO4 prepared using GAC method
Vilhelm, Ondřej ; Neoral, Jiří (referee) ; Čech, Ondřej (advisor)
Presented work investigates the problem of secondary lithium-ion cells and the different available cathode materials. We have prepared samples of LiFePO4 with the addition of different kinds of carbon materials such as Super P, Vulcan and expanded graphite. We have always created the sample with and without surfactant. Developed samples were compared by measuring electrochemical methods (cyclic voltammetry, charge and discharge cycles and impedance spectroscopy). We also modeled the three-point cell for measuring electrochemical electrode materials.
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Using konduktometric method for conductivity measurement of the corrosive layer of lead alloys
Neoral, Jiří ; Vaněk, Jiří (referee) ; Bača, Petr (advisor)
Lead-acid batteries are the oldest and most common type of secondary cells. Their biggest use is as a power source for a car starter. Bipolar lead-acid batteries could also be used for new applications such as power sources for hybrid electrical vehicles (HEV) for their high power. But there are still many technical problems limiting its use in these applications, which have to be overcome. This could cover parasite reactions as is gas creation, heat removal from the battery and another big problem is substrate corrosion. This diploma thesis concerns the actual state of bipolar lead batteries in the world with detail orientation to substrate corrosion. This thesis describes the conductometric method of lotion conductivity measurement and its modification for measurement of lead grid conductivity. From that we can find out, that when material loses more conductivity, the greater the corrosion. This thesis describes needed preparative experiments for assurance, that the conductometric method can be used for corrosion speed measurement and there are other experiments testing different lead alloys for corrosion speed.
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Impedance measurement of lead-acid accumulator properties
Vaculík, Sebastian ; Neoral, Jiří (referee) ; Abraham, Pavel (advisor)
This work deals with the new and unique four-point method measurement of the impedance characteristics for experimental positive electrode. The theoretical part provides a short introduction to the electrochemical power sources, including the lead-acid batteries, which were used for measurement. Furthermore, there is description of the principle of electrochemical impedance spectroscopy and analysis of obtained data by using the equivalent circuit, consisting of passive components. The experimental section is devoted to the description of the device, which is used for realization of connection of electrodes with Potenciostat VSP, and program which is used for the simplification of processing of results. The main aim of this bachelor thesis is to get better understanding of lead-acid accumulators and impedance measurements. At practical part of the thesis I performed first measurements by two-step method based on electrochemical impedance spectroscopy.
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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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Impedance measurement of lead-acid accumulator properties
Vaculík, Sebastian ; Neoral, Jiří (referee) ; Abraham, Pavel (advisor)
This work deals with the new and unique four-point method measurement of the impedance characteristics for experimental positive electrode. The theoretical part provides a short introduction to the electrochemical power sources, including the lead-acid batteries, which were used for measurement. Furthermore, there is description of the principle of electrochemical impedance spectroscopy and analysis of obtained data by using the equivalent circuit, consisting of passive components. The experimental section is devoted to the description of the device, which is used for realization of connection of electrodes with Potenciostat VSP, and program which is used for the simplification of processing of results. The main aim of this bachelor thesis is to get better understanding of lead-acid accumulators and impedance measurements. At practical part of the thesis I performed first measurements by two-step method based on electrochemical impedance spectroscopy.
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Thermal phenomena in lead acid batteries
Kovařík, Lukáš ; Čech, Ondřej (referee) ; Neoral, Jiří (advisor)
This thesis project solve problematic of thermal proces in lead-acid batteries. There are decribed history of lead – acid batteries, distributions of batteries, overview of construction lead – acid batteries and VRLA batteries and is decribed thermal runaway proces and basic termal process. They are listed here practical results and the measurements is concluded.
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