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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
31

Rychlonabíječ olověných akumulátorů 12 V / Fast-charger for lead-acid batteries 12 V

Kopuletý, Ondřej January 2019 (has links)
This Master thesis deals with modification of lead battery charger connection. In particular, changes are made to the control board. The theoretical part describes the principle of charging lead batteries and the description of the basic types of switching power supplies. Furthermore, the dimensioning of important components in the circuit together with the optimization of the switching frequency and the parameters of the high-frequency transformer are also presented. At the end of the thesis is the procedure of assembling the whole charger.
32

Zkoumání uhlíku jako aditiva záporné aktivní hmoty olověného akumulátoru pro hybridní elektrická vozidla / Investigation of carbon effect in negative active mass on lead-acid accumulator for HEV.

Tonar, Karel January 2010 (has links)
The lead-acid bateries for hybrid-electric vehicle (HEV) working under high-rate partial-state-of-charge (HRPSoC) conditions. The negative plates of lead-acid batteries have low charge acceptance. The cycle life of the batteries is dependent on the rate accumulation of PbSO4 on the negative plates. Addition of some carbon or graphite forms to the negative paste mix improves the charge efficieny and slows down sulfation of the negative plates. The master’s thesis wants to explain the contribution of electrochemically active carbon (EAC) additives to the mechanis of the electrochemical reaction of charge of the negative plates.
33

Zkoumání teplotních změn olověného akumulátoru v režimu hybridních vozidel / Investigation of temperature changes in the lead-acid battery system for hybrid electric vehicles

Kadrnka, Petr January 2012 (has links)
The lead-acid batteries are most commonly used electrochemical power source. The lead-acid battery is the oldest type of secondary battery cells. This lead-acid batteries have a great use in hybrid electric vehicles (HEVs), which operate in different modes of vehicle operation. This is related to changes in battery temperature, caused by Joule heat taking place during discharging and chargingg the battery in a vehicle operation. The lead-acid batteries in hybrid electric vehicles work in mode PSoC.
34

Zkoumání vlivu aditiv elektrolytu na vlastnosti olověných akumulátorů / The examination of the influence of electrolyte additives to lead acid batteries properties

Abrle, Ladislav January 2013 (has links)
Lead-acid battery serves as the primary power source for vehicles. The total lifetime is determined by the parameters identified in the production, but also handling the operation and maintenance. This work deals with the effect of additives in the electrolyte added before and after the formation of cells lead-acid battery. The work deals with the influence of these additives during cyclic mode.
35

Teplotní změny při pulzním nabíjení olověného akumulátoru / Temperature changes during pulse charging of lead-acid accumulator

Přikryl, Kamil January 2014 (has links)
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.
36

Energy-Water-Agriculture Nexus Mini-grids to Power Rural Productive Hubs in Sub-Saharan Africa : A case study of Walta Jalala village in Bedeno Woreda of Ethiopia

Biramo, Israel January 2020 (has links)
The thrive to achieve Sustainable Development Goal 7 is never been easy, and numbers are still showing that Sub-Saharan Africa is lagging in access to electricity index. Most of the energy poor communities residing in the rural part of the region, this by itself is a conundrum with multifaceted implications. The high capital expenditure for renewable energy technologies, the low paying ability of the society in Sub-Saharan Africa, the unavailability of anchor customer’s and so on needs new means of approaching the access problem. This study aims to enlighten policy makers on promoting energy as input to production than merely focusing on the access issue. In the report, a renewable mini-grid powering a local economic activity of a remote agrarian village in Ethiopia is discussed. Through a simulation study using PVsyst and Homer Pro tools, a yearly optimized PV diesel hybrid system with rounded up lowest LCOE of $0.17/kWh is obtained for the village in the case study. The LCOE of the mini-grid with lead acid battery and Li-ion battery is also studied at a yearly average operating temperature range of 10 to 40 ℃. The simulation-based study demonstrated that mini-grid systems with lead acid and Li-ion battery have fairly comparable LCOE between 10 to 20 ℃, however the Li-ion battery results in a lower LCOE for operating temperature beyond 25 ℃. The study has shown that mini-grids with productive energy can be cost effective option for powering areas where the grid-connection is cost and time intensive to address the energy poverty issue by 2030 or after.
37

Method for Monitoring and Analyzing Lead-Acid Batteries

Chobot, Simon, Hanssen, Johan January 2019 (has links)
Lead-acid batteries today are commonly used in the automotive industry with a considerable span of purposes, yet historically, a primary purpose of cranking the engine at ignition which does demand a high current drainage from a battery. These high drainages later result in a health implication which can be hard to detect without the proper tools and this thesis focuses on the development of those tools.To insure the health of a battery turns out to be a handy feature for most drivers today and early signs of deterioration may even warn a user in advance of damage or failure to insure that proper care is taken with a goal to extend every battery’s lifespan.The results of this thesis demonstrates great accuracy for the tools necessary for an accurate health estimation yet lacks extensive testing data to clearly verify an actual health estimation. Where the chapter of Further Work includes specific tests, error corrections and examples of how to achieve even greater accuracies. / Blybatterier används idag vanligen inom bilindustrin för ett stort antal ändamål, men historiskt sett har det ett primärt syfte att driva startmotorn vid tändning, vilket kräver en hög ström brukas från batteriet. Dessa höga strömmar resulterar senare i en hälsopåverkan som kan vara svår att upptäcka utan de korrekta verktygen och denna avhandling fokuserar på utvecklingen av just dessa verktyg.Att fastställa batteriets hälsa är en användbar tillgång för de flesta förare idag och tidiga tecken på försämring kan till och med varna en användare i förväg om nära förestående skador och således försäkra sig om att lämpliga åtgärder vidtas, med ett mål att förlänga alla batteriernas livslängd.Resultaten av denna avhandling visar en stor noggrannhet för de verktyg som behövs för en exakt hälsoestimering men saknar omfattande testdata för att tydligt verifiera denna estimering. I kapitlet “Further Work” ingår specifika tester, felkorrigeringar och exempel på hur man uppnår en ännu större noggrannhet.
38

Economic and Environmental Analysis of Cool Thermal Energy Storage as an Alternative to Batteries for the Integration of Intermittent Renewable Energy Sources

Anderson, Matthew John 17 January 2015 (has links)
The balance of the supply of renewable energy sources with electricity demand will become increasingly difficult with further penetration of renewable energy sources. Traditionally, large stationary batteries have been used to store renewable energy in excess of electricity demand and dispatch the stored energy to meet future electricity demand. Cool thermal energy storage is a feasible renewable energy balancing solution that has economic and environmental advantages over utility scale stationary lead-acid batteries. Two technologies, ice harvesters and internal-melt ice-on-coil cool thermal energy storage, have the capability to store excess renewable energy and use the energy to displace electricity used for building cooling systems. When implemented by a utility, cool thermal energy storage can replace large utility scale batteries for renewable energy balancing in utility regions with high renewable energy penetration. The California Independent System Operator (CAISO) region and the Electric Reliability Council of Texas (ERCOT) are utility regions with large solar and wind resources, respectively, that can benefit from installation of cool thermal energy storage systems for renewable energy balancing. With proper scheduling of energy dispatched from cool thermal energy storage, these technologies can be effective in displacing peak power capacity for the region, in displacing traditional building cooling equipment, and in recovering renewable energy that would otherwise be curtailed. / Master of Science
39

Capacity and Life Estimation of Flooded Lead Acid Batteries using Eddy Current Sensors

Reddy, T Mohan January 2016 (has links) (PDF)
Lead acid batteries are widely used in domestic, industrial and automotive applications. Even after lot of advancements in battery technologies, lead acid cells are still in use because of their high capacity and low cost. To use any battery effectively, first we should be able to identify the available capacity or State of Charge (SoC). There are many techniques available to measure SoC of a lead acid battery. One such unique method is to measure the capacity using eddy current sensors. This method is unique because it is non-obtrusive and online. Eddy current sensors (ECS) are wire wound inductors which work on the principle of electromagnetic induction. Eddy currents are the currents generated on a conductive material when it is kept in a varying magnetic. Eddy current sensors generate varying magnetic eldest and will be able to identify the properties of conductive materials like thickness, conductivity, material composition etc. Also they can be used as proximity sensors. Lead acid batteries use lead metal as cathode. Upon usage(discharge) the lead metal converts to lead sulfate and revert back to lead after charging. These changes in lead electrode can be monitored using eddy current sensors. The impedance of an eddy current sensor will change when it is kept close to the lead electrode when the battery is charging or discharging. These impedance parameters can be monitored to determine the battery SoC. When lead is deposited on cathode, there will be more eddy current loss in the target and the total resistance of coil increases. On the other hand, when lead is deposited on the electrode because of increase in the magnitude of eddy currents which oppose the source magnetic, the total inductance of coil decreases. We can observe exactly opposite behaviour of coil resistance and inductance when the lead electrode is converted to less conductive lead sulfate. There is a lot of research on using ECS to measure SoC of lead acid batteries and there are still many challenges to be addressed. First we have explained about different circuit designs we have used to monitor the battery capacity using eddy current sensors. After that, we have explained about our complete experimental setup and the procedure to measure the sensor parameters using the setup. Then, we have discussed about different issues involved in the eddy current sensing based state of charge measurement. Eddy current sensors are affected by temperature variations. We have studied the coil resistance behaviour with temperature at different frequencies using simulations and experiments. We have obtained the conditions for linear variation of coil resistance with temperature. The measured temperature compensation scheme is applied and the results are discussed. We have also modified the measurement system design in order to minimize the lift o errors. We have used a metallic clamp structure to minimize the lift o errors. We have used finite element analysis based simulations to study different design parameters and their effect on the sensitivity of eddy current sensor. We have created 2D eddy current models and the sensitivity of coil resistance is computed by changing the coil dimensions and the core permeability. We have also performed error analysis and computed the error due to the tilt angle shift between coil and electrode. We have also computed the error due to the internal heating of battery. We have also studied the effect of acid strati cation on state of charge for both sealed and hooded batteries. We have proposed a multi coil method to minimize the errors in SoC measurement due to acid strati cation for Flooded type batteries. We have used finite element analysis based simulations to compute the error due to acid strati cation by increasing the number of coils. Finally we have derived the equation for electrode Q factor using the transformer model of eddy current sensor. The derived Q factor equation is then used to study the aging of lead acid batteries both by using experiments and simulations. Finally we have explained a detail procedure to measure the state of charge(SoC) and state of health(SoH) of a hooded lead acid battery using eddy current sensing method.
40

Avaliação técnico-econômica do uso de baterias para a racionalização de energia elétrica em aviários de frango de corte / Technical-economic evaluation of the use of batteries for electricity rationalization in poultry production

Moreno, Ana Carolina Sala 24 February 2015 (has links)
Made available in DSpace on 2017-07-10T15:14:19Z (GMT). No. of bitstreams: 1 Ana Carolina_ Moreno.pdf: 1431859 bytes, checksum: 0d4aa5c4361adead46314fbf8e1b8619 (MD5) Previous issue date: 2015-02-24 / Electricity is one of the main raw materials used in poultry production and it is central to operate and maintain the poultry farms in operation. An aviary requires electricity to supply the various motors and electrical devices that are part of the lighting systems, exhausting, heating, food, among others. Aiming to provide incentives for poultry producers, specifically in the state of Paraná, in 2007, the Poultry Night Program was implemented, in which the government grants discounts in electricity tariff for poultry farmers at night. In this work it was proposed different energy storage systems by using lead-acid batteries and nickel chloride and sodium batteries for supplying loads of four poultry located in the city of Francisco Alves, PR, over a year. For this, it was studied the feasibility of using energy storage systems with battery bank in the higher tariff period and charging the battery bank in the reduced tariff period, comprising of 9:30 PM to 6:00AM (next day). For this project, the two storage systems proved to be uneconomical, since the initial investments by the battery banks are very high compared with the costs avoided with electricity through the use of these systems. KEYWORDS: energy / A energia elétrica é um dos principais insumos utilizados na produção avícola, sendo fundamental para operar e manter os aviários de frango de corte em funcionamento. Um aviário necessita de energia elétrica para alimentar os diversos motores e dispositivos elétricos que compõem os sistemas de iluminação, exaustão, aquecimento, alimentação, entre outros. Visando dar incentivo aos produtores de frangos de corte, especificamente no estado do Paraná, em 2007, foi implantado o Programa Avicultura Noturna, no qual o governo concede descontos na tarifa de energia elétrica para avicultores no período noturno. Neste trabalho foram propostos diferentes sistemas de armazenamento de energia através da utilização de baterias de chumbo-ácido e baterias de cloreto de níquel e sódio para alimentar o conjunto de cargas de quatro aviários situados no município de Francisco Alves-PR, ao longo de um ano de alojamento de aves. Para isto foi estudada a viabilidade de utilização dos sistemas de armazenamento de energia através de banco de baterias no período de tarifa mais elevada e carregamento do banco de baterias no período de tarifa reduzida, que compreende das 21h 30 min às 6 horas (dia seguinte). Para este projeto, os dois sistemas de armazenamento propostos se mostraram inviáveis economicamente, uma vez que o investimento inicial dos bancos de baterias são muito elevados se comparados com os gastos evitados com energia elétrica através do uso destes sistemas.

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