This bachelor thesis investigates what kind of battery system that is suitable for an electric driveline equipped with a mechanical fly wheel, focusing on a battery with high specific energy capacity. Basic battery theory such as the principle of an electrochemical cell, limitations and C-rate is explained as well as the different major battery systems that are available. Primary and secondary cells are discussed, including the major secondary chemistries such as lead acid, nickel cadmium (NiCd), nickel metal hydride (NiMH) and lithium ion (Li-ion). The different types of Li-ion chemistries are investigated, explained and compared against each other as well as other battery technologies. The need for more complex protection circuitry for Li-ion batteries is included in the comparison. Request for quotations are made to battery system manufacturers and evaluated. The result of the research is that the Li-ion NMC energy cell is the best alternative, even if the cost per cell is the most expensive compared to other major technologies. Due to the budget, the LiFeMnPO4 chemistry is used in the realisation of the final system, which is scaled down with consideration to the power requirement.

Batteries have imparted momentum to the process of transition towards a green future. However, mass application of batteries is obstructed due to their explosive nature, a trait specific to Li-Ion batteries. To cater to an efficient battery utilization, an introduction of a battery management system would provide an ultimate solution. This thesis deals with different aspects crucial in designing a battery management system for high energy as well as high power applications. To build a battery management system capable of predicting battery behavior, it is necessary to analyze the dynamic processes happening inside the battery. Hence, a battery equivalent circuit model is proposed in this thesis as well as proper analysis is done in MATLAB to project a generic structure applicable to all Li-Ion chemistries. The model accounts for all dynamic characteristics of a battery including non-linear open circuit voltage, discharge current and capacity. Effect of temperature is also modeled using a cooling system. The model is validated with test current profiles. Less than 0.1% error between measured and simulated voltage profiles indicates the effectiveness of the proposed model to predict the runtime behavior of the battery. Furthermore, the model is implemented with the energy as well as the power battery pack. State of charge calculations are performed using the proposed model and the coulomb counting method and the results indicate only a 4% variance. Therefore, the proposed model can be applied to develop a real-time battery management system for accurate battery states estimation.

This thesis presents novel battery pack designs and control methods to be used with battery packs enhanced with power electronics. There are two areas of focus: 1) intelligent battery packs that are constructed out of many hot swappable modules and 2) smart cells that form the foundation of a completely decentralised battery management system (BMS). In both areas, the concept of active loading/charging is introduced. Active loading/charging balances the cells in a battery pack by loading each cell in proportion to its capacity. In this way, the state of charge of all cells in a series string remain synchronized at all times and all of the energy storage potential from every cell is utilized, despite any differences in capacity there may be. Experimental results from the intelligent battery show how the capacity of a pack of variably degraded cells can be increased by 46% from 97 Wh to 142 Wh using active loading/charging. Engineering design challenges of building a practical intelligent battery pack are addressed. Start up and shut down procedures, and their respective circuits, were carefully designed to ensure zero current draw from the battery cells in the off state, yet also provide a simple mechanism for turning on. Intra-pack communication was designed to provide adequate information flow and precise control. Thus, two intra-pack networks were designed: a real time communication network, and a data communication network. The decentralised control algorithms of the smart cell use a small filtering inductor as a multi-purpose sensor. By analysing the voltage across this filtering inductor, the switching actions of a string of smart cells can be optimised. Experimental results show that the optimised switching actions reduce the output voltage ripple by 83% and they synchronize the terminal voltages of the smart cells, and by extension, their states of charge. This forms the basis of a decentralised BMS that does not require any communication between cells or with a centralised controller, but can still achieve cell balancing through active loading/charging.

>Magister Scientiae - MSc / The Platreef, is a contact-type pyroxenitic reef in the Northern Limb of the Bushveld Complex, enriched in platinum group elements (PGE) and base metal sulfides (BMS). Relatively subdued mining in the Platreef, compared to RLS, has been attributed to limited knowledge regarding irregular distribution, complex style and genesis of PGE mineralisation in the Platreef. This study was, therefore, aimed at investigating the petrogenesis of the Platreef, particularly to evaluate whether the formation of the ore reefs resulted from a single or multiple sill-like magma intrusions. The study also sought to unveil the interplay of fractional crystallisation, hydrothermal fluid activities, floor rock and crustal contamination on the formation of Platreef types, PGE mineralisation and the magma source.

This thesis examines alternatives for power supply for a heavy truck application based on five different modular multilevel converter configurations that ultimately feed a 3-phase motor. Advantages and disadvantages of the different configurations are being discussed as well as other important factors that play a role in what configuration that is beneficial for the intended application. How half- or full-bridge submodules and battery cells relate to each other to achieve a desired voltage are being explained and calculated. Power losses of the converter submodules are being calculated as well as how a specific battery capacity, with increasing average power consumption, performs uphill according to set requirements. It turns out to be the double-armed modular multilevel converter configurations that has the best performance when it comes to utility, energy storage and the lowest power losses.

Batteries are becoming popular in the trend of electrification. Performance andlifespan of a battery pack are closely related to how it has been utilized. Withproper balancing control to slow down aging process, variances of capacity andresistance between battery cells can be maintained at a better level. Among balancing methods, dissipative balancing is still the most common method for itssimplicity in control, low cost and high speed. Non-dissipative balancing methods like converter-based and capacitor-based are of researchers’ interest becauseof less heat generated and superior efficiency. In this thesis, the converter-based balancing method is investigated. A modular multilevel converter (MMC) with Pulse-Width Modulation (PWM) pattern iscompared with another MMC with Nearest-Level Modulation (NLM). The speedto balance six battery sub-modules, output power and battery current harmonicsare examined.

京都大学 / 0048 / 新制・課程博士 / 博士(医科学) / 甲第20811号 / 医科博第82号 / 新制||医科||6(附属図書館) / 京都大学大学院医学研究科医科学専攻 / (主査)教授 長船 健二, 教授 妻木 範行, 教授 村井 俊哉 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM

Blybatterier är ett uppladdningsbart batteri som har utvecklats i över 100 år och används i ett brett spektrum där det krävs en långvarig och pålitlig strömkälla. Däremot har blybatterier en begränsad livslängd och kapacitet som styrs av underhållet av batteriet. En faktor som påverkar batteriets kapacitet är sulfatering, vilket sker när batteriet urladdas och stått med en låg laddningsstatus under en lång tid. När transporter av blybatterier sker är det därför viktigt att ha tillförlitliga och säkra processer för att säkerställa batteriets kvalitet genom hela transportkedjan. Syftet med denna studie var att ta fram konceptmodeller genom att undersöka och identifiera olika metoder för att säkerställa kvaliteten på blybatterierna under långa transporter. Konceptmodellernas syfte var även att öka livslängden på blybatterierna med hänsyn till användarvänlighet och miljöpåverkan. Följande forskningsfrågor har besvarats: I. Hur kan företag inom tillverkningsindustrin säkerställa kvalitet på ett blybatteri under långa transporter?II. Hur kan urladdning av blybatterier undvikas genom övervakning av batteriet? En fallstudie har genomförts på Volvo CE, ett globalt företag som verkar inom interkontinentala och regionala transporter. I Pedeneiras, Brasilien, etablerades en produktionsanläggning år 1995 för anläggningsmaskiner som sedan levereras till återförsäljare i Nord- och Sydamerika samt Australien. Anläggningsmaskinerna har ett 24 V-system som innehåller två stycken seriekopplade 12 V blybatterier. Transporten för anläggningsmaskinerna från produktionsanläggningen till återförsäljare kan ta upp till två månader vilket innebär att batterierna riskerar att självurladdas och blir permanent skadade. Semistrukturerade intervjuer genomfördes på Volvo CE i Eskilstuna, Volvo GTT samt produktionsanläggningen i Pederneiras, för att samla in relevant data. Parallellt har en litteraturstudie utförts för att utforska tillgängliga teknologier samt tekniker för att underhålla laddningen och mäta batteriets status. Studien resulterade i tre stycken konceptmodeller som bygger på den empiriska data samt teknologier som framkom under litteratursökningen. Konceptmodell I är ett förslag på implementering av ett individuellt serienummer på blybatterierna. Denna lösning skapar transparens genom att kunna spåra batterierna, identifiera och logga batteriets status när maskinen har lämnat produktionsanläggningen. Genom att sammankoppla detta med digitala verktyg möjliggörs spårning av det individuella batteriet. Konceptmodell II innebär att en batterisensor placeras på batteriet som med fjärrstyrning möjliggör övervakning av batteriets status och position. Detta innebär att batteriet kan övervakas på distans i realtid och användaren varnas automatiskt om batteriets spänning är för låg. Detta innebär att batteriet kan laddas upp innan det förlorat sin kapacitet vilket har en positiv inverkan på miljön samt användarvänligheten. Konceptmodell III är en utökning av föregående koncept men innebär att underhållsladdningen automatiseras med solpaneler och laddningsregulator. Lösningen tar hänsyn till både användarvänligheten och miljöpåverkan genom att säkerställa att batteriet inte urladdas.

Building management system (BMS) offers a wide range of measurements and historical data about the building but few types of researches use these data to analyze the building performance. This study aims to explore the indoor climate and building insulation by taking advantage of the BMS of the study case, which 767 sensors are installed in the room and wall structures and the signal data are available at the online web application. In addition, during the inspection, several error sensors and meters are detected are discussed as feedback for the system. It is concluded that the building management system is a good tool to study the building performance in different aspects and the measurements from the sensors are helpful but need validation by conducting a further field measurement in the building.

No description available.