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"Lithium ion batteries have dominated the portable electronics market and have the potential to dominate large-scale battery applications including hybrid and electric vehicles, as well as grid storage, because of their high energy and power densities1,2. It is well known that conventional electrolytes show poor anodic stabilities above 4.5 V versus Li/Li+.3 As a result, high voltage electrolytes are essential for the development of next generation high energy lithium ion batteries. Both fluorinated electrolytes and additives can be introduced into the electrolyte system.4 In this work, fluorinated electrolytes were used in both graphite-LiNi0.5Co0.2Mn0.3O2 (NCM523) (operated between 3.0 - 4.6 V) and graphite- LiNi0.5Mn1.5O4 (LNMO) (operated between 3.5 - 4.9 V) full cell systems. The baseline electrolyte for all cells (referred to as Gen2) was composed of 1.2M LiPF6 dissolved in a mixture of EC and EMC (3:7 in weight ratio). After a series of electrochemical tests, compared to the baseline electrolyte, the fluorinated electrolytes displayed significantly enhanced performance under both high cut off voltage and high temperature (55 oC). The post test analysis results showed that the cycled electrode can not only reach a much more stable interface but also overcome the crystal structure change after long term cycling when the fluorinated electrolyte system was used. In addition to changing the solvent, a series of additives were designed, synthesized and evaluated for high-voltage Li-ion battery cells using a Ni-rich layered cathode materials LiNi0.5Co0.2Mn0.3O2 (NCM523). The repeated charge/discharge cycling for NCM523/graphite full cells using Gen2 with 1 wt % of these additives as electrolytes was performed. Electrochemical performance testing and post analysis result demonstrated that our as selected or designed cathode additives could passivate the cathode and prevent the cathode from side reactions. The developed methodology could provide fundamental direction in the design and investigation of better electrolytes for the next generation lithium ion batteries."

This research proposes a smart battery management system applied to Li-Battery. The system not only can monitor the batteries for all kinds of parameters but also modify them by users. Besides, in estimating the residual capacity of Li-ion batteries, an automatic measurement platform is set up in order to record the data of Li-battery in different kinds of charge-discharge condition and to analysis the characteristics. In monitoring used battery capacity, Modified-Coulomb-Measuring method is proposed and it can accurately estimate the residual capacity according to the effect of output current and environment temperature. In addition to estimate the residual capacity accurately, Smart Battery System can record the information of Li-batteries over a long period of time, and the log files can be used for further battery characteristics analysis.

Mobile devices have become increasingly ubiquitous as they serve many important functions in our daily lives. However, there is not much research on remote threats to the battery and power systems of these mobile devices. The consequences of a successful attack on the power system of a mobile device can range from being a general nuisance, financial harm, to loss of life if emergency communications were interrupted. Despite the relative abundance of work on implementing chemical and physical safety systems for battery cells and power systems, remote cyber threats against a mobile battery system have not been as well studied. This work created a framework aimed at auditing the power systems of mobile devices and validated the framework by implementing it in a case study on an Android device. The framework applied software auditing techniques to both the power system and operating system of a mobile device in a case study to discover possible vulnerabilities which could be used to exploit the power system. Lessons learned from the case study are then used to improve, revise, and discuss the limitations of the framework when put in practice. The effectiveness of the proposed framework was discovered to be limited by the availability of appropriate tools to conduct vulnerability assessments.<br>

The aim of this project is to nd the optimal size battery for an already installed PV system in a family house in Southern Sweden. First, the existing system is modelled and validated. Then a new model including a battery is built. In this model it is assumed that the aim of the battery is to maximize the self-consumption of the house. A sensitivity analysis is performed in order to study the inuence of the battery capacity on the electricity uxes between the house and the grid. The protability of the project is then investigated, considering the current tari schemes for thehouse and for the "average" Swedish house. Eventually the possibility of applying price-dependent control strategies to the battery is investigated. The primary conclusion is that a battery installation is not protable for the studied house whether the incentives provided by the Swedish government are considered or not. Yet a subsidized installation would be protable for a house subject to the average Swedish electricity price. Another conclusion is that the current hourly volatility in the electricity price is not high enough to make reasonable the use of price dependent battery control strategies. Their use would lead to better economical performance, with respect to the simplest battery control strategy, in case of increased volatility. / Malet av det har projektet ar att hitta batteri med den basta storleken for en existerande solcellssystem i en villa i Sodra Sverige. Forst, det existerande systemet modelleras och valideras. Sedan byggs en ny modell som innehaller ett batteri. I den har modellen antas att malet av batteriet ar att maximera sjalvkonsumption av villan. En kanslighetsanalys utfors for att studera inverkan av batteri kapacitet pa el ussmedel mellan villan och natet. Darefter, lonsamheten av projektetet unders oktes, med tanke pa den bentliga tarisystem for den utforskade villan och den "genomsnitt" Svenska villa. Slutligen, mojligheten att tillampa prisberoende batterikontrollstrategier undersoks. Den primara slutsats ar att en batteriinstallation ar inte lonsam for den studerade villa, med eller utan bidrag. Anda en subventionerad installation skulle vara lonsam for ett hus som utsatts for genomsnitt svenska elpriset. En annan slutsats ar att den nuvarande volatilitet i elpriset ar inte tillrackligt hog for att gora lamplig den anvandning av prisberoende batterikontrollstrategier. Deras anvandning skulle leda till battre ekonomisk prestanda, med avseende pa den enklaste batteristrategi, om prisvolatilet okningar.

The DC House project strongly relies on renewable energy sources to provide power to the house for various loads. However, when these sources are unable to provide power at a certain time, a back-up energy source from a battery must be readily available to fulfill the house’s power needs. This thesis proposes a bi-directional flyback power converter to allow a single-stage power path to charge the battery from and to discharge the battery to the DC House 48 V system bus. The design, simulation, and hardware prototype of the proposed flyback bi-directional converter will be conducted to demonstrate its feasibility. Results from a 35W prototype demonstrate the operation of the proposed converter for both charging and discharging purposes.

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It is known that Sweden is categorised by being one of the regions that experience low solar radiation because it is located in the northern hemisphere that has a low potential of solar radiation during the colder seasons. The government of Sweden aim to promote a more sustainable future by applying more renewable initiative in the energy sector. One of the initiatives is by applying more renewable energy where PV panels will play a greater role in our society and in the energy sector. However, the produced energy from the PV panels is unpredictable due to changes in radiation throughout the day. One great way to tackle this issue is by combining PV panels with different energy storage system. This thesis evaluates an off-grid rowhouse in Eskilstuna Sweden where the PV panels are combined with a heat pump, thermal storage tank, including batteries and hydrogen system. The yearly electrical demand is met by utilizing PV panels, battery system for short term usage and hydrogen system for long-term usage during the colder seasons. The yearly thermal demand is met by the thermal storage tank. The thermal storage tank is charged by heat losses from the hydrogen system and thermal energy from heat pump.The calculations were simulated in Excel and MATLAB where OPTI-CE is composed with different components in the energy system. Furthermore, the off-grid household was evaluated from an economic outlook with respect to today’s market including the potential price decrease in 2030.The results indicated that the selected household is technically practicable to produce enough energy. The PV panels produces 13 560 kWh annually where the total electrical demand reaches 6 125 kWh yearly (including required electricity for the heat pump). The annual energy demand in terms of electricity and thermal heat reaches 12 500 kWh which is covered by the simulated energy system. The overproduction is stored in the batteries and hydrogen storage for later use. The back-up diesel generator does not need to operate, indicating that energy system supplies enough energy for the off-grid household. The thermal storage tank stores enough thermal energy regarding to the thermal load and stores most of the heat during the summer when there are high heat losses due to the charge of the hydrogen system. The simulated energy system has a life cycle cost reaching approximately k$318 with a total lifetime of 25 years. A similar off-grid system has the potential to reduce the life cycle cost to k$195 if the energy system is built in 2030 with a similar lifespan. The reduction occurs due to the potential price reduction for different components utilized in the energy system.

Recently in more or all electric vehicles, higher voltage batteries are used which employ large number of cells in series. Series connection among cells may lead to single point of failures, safety and charge equalization issues that demand complex control and costly and/or lossy battery management methods. Most present day high voltage batteries use dissipative-charge balancing methods, which result in poor efficiency, additional thermal management burden and lower overall vehicle range. Furthermore, the output voltages of such batteries remain unregulated and may widely change with load and environmental conditions, complicating the overall power pass design of the electrical power system. As a step forward to address these issues, this thesis studies a fault-tolerant regulated active high voltage electric accumulator with integrated power electronics for safe charge and discharge of the high voltage energy storage system. / Thesis / Master of Applied Science (MASc)

Energy Storage Battery Systems (BESS) will have an important role in the transformation from conventional energy systems to the decentralized energy systems of the future with a larger share of renewable energy sources. At the same time, the high investment costs for batteries are a challenge to the development and transformation of the Swedish energy system. This study examines the technical and economic performance of a battery system in a case study, where it is connected to a waste vacuum machine with daily power peaks that are higher than the base demand. The purpose of the battery system is to combine it for peak shaving and for Svenska Kraftnät's market for grid services. This study also examines how a service-based business model, where the ownership of the battery is transferred to a third party, affects value proposition, value creation and value capture. The results from this study show that actual cost savings are realized through peak shaving as well as opportunities for revenue by offering the battery for grid services. Furthermore, scenario modeling shows on certain operational insights, that at a certain level of compensation for grid services, it is most profitable to perform as high peak shaving as possible. Offering the battery as a service is shown to provide additional benefits for customers and companies, while society and the environment benefit above all from the battery technology itself. / Stationära batterisystem (BESS) kommer ha en viktig roll i transformationen från konventionella energisystem till framtidens decentraliserade energisystem med större andel förnyelsebara energikällor. Samtidigt är de höga investeringskostnaderna för batterier ett hinder för utvecklingen och transformationen av det svenska energisystemet. Denna studie undersöker ett batterisystems tekniska och ekonomiska prestanda i en case studie, där det är kopplat till en sopsug med dagliga effekttoppar som är högre en basbehovet. Syftet med batterisystemet är att kombinera det för effektkapning och för Svenska Kraftnäts balansmarknad. Denna studie undersöker även hur en tjänstebaserad affärsmodell, där ägarskapet av batteriet flyttas till en tredje part påverkar värdeerbjudande, värdeskapande och värdefångst. Resultatet från denna studie visar att faktiska kostnadsbesparingar blir realiserade genom effektkapning samt möjligheter till intäkter genom att erbjuda batteriet för stödtjänster. Vidare visar scenariomodellering på vissa operationella insikter, att det till en viss nivå av ersättning för stödtjänster är det mest lönsamt att utföra så hög effektkapning som möjligt. Att erbjuda batteriet som tjänst visas ge ytterligare fördelar för kunder och företag, medan samhället och miljön gynnas framför allt av själva batteritekniken.