Zinc electrodeposition is currently a hot topic because of its widespread use in rechargeable zinc-air batteries. However, Zn deposition has received little attention in organic solvents with much higher ionic conductivity and current efficiency. In this study, a Zn-betaine complex is synthesized by using ZnO and betainium bis[(trifluoromethyl)sulfonyl]imide and its electrochemical behavior for six organic solvents and electrodeposited morphology are studied. Acetonitrile allowed dendrite-free Zn electrodeposition at room temperature with current efficiencies of up to 86%. From acetonitrile solutions in which Zn, Pb, and Cu complexes are dissolved in high concentrations, Zn and Pb/Cu are efficiently separated electrolytically under potentiostatic control, allowing the purification of solutions prepared directly from natural ores. Additionally, a highly flexible Zn anode with excellent kinetics is obtained by using a carbon fabric substrate. A rechargeable zinc-air battery with these electrodes shows an open-circuit voltage of 1.63 V, is stable for at least 75 cycles at 0.5 mAcm⁻² or 33 cycles at 20 mAcm⁻², and allows intermediate cycling at 100 mAcm⁻².

A new preparation concept of a partially porous solid-state bilayer electrolyte (BE) for high-temperature sodium-ion batteries has been developed. The porous layer provides mechanical strength and is infiltrated with liquid and highly conductive NaAlCl4 salt, while the dense layer prevents short circuits. Both layers consist, at least partially, of Na-β-alumina. The BEs are synthesized by a three-step procedure, including a sol-gel synthesis, the preparation of porous, calcined bulk material, and spin coating to deposit a dense layer. A detailed study is carried out to investigate the effect of polyethylene oxide (PEO) concentration on pore size and crystallization of the bulk material. The microstructure and crystallographic composition are verified for all steps via mercury intrusion, X-ray diffraction, and scanning electron microscopy. The porous bulk material exhibits an unprecedented open porosity for a NaxAlOy bilayer-system of ≤57% with a pore size of ≈200–300 nm and pore volume of ≤0.3 cm3∙g−1. It contains high shares of crystalline α-Al2O3 and Na-β-alumina. The BEs are characterized by impedance spectroscopy, which proved an increase of ionic conductivity with increasing porosity and increasing Na-β-alumina phase content in the bulk material. Ion conductivity of up to 0.10 S∙cm−1 at 300 °C is achieved.

Lithium ion batteries (LIBs) are widely used for storing and converting chemical energy into electrical energy. During battery operation, lithium ions move between electrode materials, enabling energy storage. However, aging mechanisms like lithium plating can negatively impact battery performance and lifetime. Lithium plating occurs when lithium ions are reduced to metallic lithium on the graphite electrode. The undesired Li plating in LIBs leads to dendrite formation that may puncture the separator, causing internal short-circuit and ultimately thermal runaway. This study aims to investigate the internal processes of LIBs during charge and discharge. Two analysis methods are employed: online electrochemical mass spectrometry (OEMS) and acoustic emission monitoring (AEM). OEMS is a gas analysis technique that combines electrochemical measurements with mass spectrometry to provide real-time testing of cells. OEMS allows identifying and quantifying gas evolution/consumption of chemical species. AE is a diagnostic tool, offering monitoring the health of LIBs through detection and characterisation of stress waves produced by parasitic mechano-electrochemical events. The results indicates that the formation of SEI thin film layer, generated gases like hydrogen and ethylene, while consuming carbon dioxide. During induced lithium plating, hydrogen and carbon dioxide were consumed, and ethylene gas was produced, due to new SEI film formation process. The acoustic emission analysis indicated that lithium plating was an active process, whereas SEI formation was less AE active. Further research is needed to understand the relationships and significance of these processes for battery performance and safety. Overall, this study highlighted the importance of investigating aging mechanisms in LIBs to enhance their performance and longevity. By combining OEMS and AE, it was possible to analyse the batteries behaviour during cycling. The evolution of gas and acoustic signals provided insights into the reactions and processes occurring inside the battery during cycling.

Because of the changing energy supply landscape, with the transition towards renewable energy, an emerging demand for energy storage systems (ESS) is expected in the near future. Battery energy storage is promising to contribute to mitigate the greenhouse gas emissions, but face issues considering resource use (IEA, 2023; IRENA, 2022). Sodium-ion batteries are a promising technology for the ESS-market, expected to take up 21 % of new installations by 2030. This means an anticipated demand of about 50 GWh of sodium-ion cells required in 2030. Key drivers for the expected entrance of sodium-ion storage are the low price, high abundance of cell materials and expectations of a more safe and sustainable battery. Lithium-ion technology is currently dominating the energy storage market, but have concerns with ethical resource supply and rising mineral prices combined with the growing demand. (BloombergNEF, 2023; IEA, 2023) There is a scarcity of information considering sodium-ion environmental reporting (Liu et al., 2021; Peters et al., 2021). Therefore, the purpose of this study is to evaluate the environmental aspect of sodium-ion storage technology. Thereby, with this study a life cycle assessment (LCA) is performed on a specific sodium-ion cell. The specific scope for the thesis is to look at 1 kWh of produced battery energy storage, in a cradle-to-gate perspective. The results are to be presented with a decomposition of the emissions across the value chain including materials, transport, and energy influence. As well a division of the cell materials impacts are demonstrated. For the assessed cell, it is assumed to be intended for a giga scale production (>1 GWh annual cell storage produced). Hypothetically this is to be placed in Europe, with both a global and a local supply chain presented. In order with European initiatives, there is a guideline called PEFCR, that recommends how to access the environmental footprint of different products. Among these guidelines, there is a certain standard for battery environmental assessment, which was pursued to be followed. According to these recommendations, the methodology of this assessment will include 16 environmental perspectives, called EF2.0. The EF2.0 emission categories presented as main result are Climate Change (total), Acidification, Resource Use (fossils), Resource Use (minerals & metals), and Particulate Matter, since these are considered relevant for batteries by PEFCR. (European Commission and ReCharge, 2018) Furthermore, it was chosen for this study to have its core in analysing the EF2.0 Climate Change impact, with the aim to identify measures on how to reduce the carbon footprint caused by the cell’s life cycle. With the perspective of the 16 environmental effects, a sodium-ion current state scenario was put in focus. On top of this, a decarbonized scenario is presented for the EF2.0 Climate Change impact. For the current state scenario, a comparison is made with a lithium-ion cell from industry, produced from fossil-free energy. This is framing the sodium-ion environmental results in the perspective of how a decarbonized lithium-ion cell performs environmentally. Both the sodium and lithium cells included in the comparison, have the aim to be used for energy storage system applications (ESS). Regarding the results for the 16 environmental categories, overall, the cathode is the main driver for emissions, followed by electrolyte and anode. Furthermore, in the decarbonized scenario, it is illustrated that implementing certain measures within the value chain could reduce the sodium-cell carbon emissions with potentially more than half of what is estimated today. Altogether, the sodium-ion value chain is in an emerging expansion phase (Rho motion, 2023), with a young supply chain starting to form. It is discussed that in the near future, with higher energy density on sodium cells commercialized (Peters et al., 2021), the environmental footprint for sodium-ion could significantly improve. Anyhow, the strongest indication from this study, is that the resource use from minerals and metals drastically would reduce with a technology switch from lithium to sodium. Among the 16 environmental impacts as a whole, the main trend is that sodium-ion cells induce less harm on the environment compared to lithium technologies. Certainly, in the future sodium-ion cells could be a low cost and sustainable option available for energy storage systems. / I och med dagens förändrade energiförsörjningslandskap, med en pågående trend mot mer förnybar energi, förväntas en ökad efterfrågan på storskaliga energilagringssystem (ESS) inom en snar framtid. Däribland är batterilagring lovande för att bidra till att minska utsläppen av växthusgaser, men försörjningen av batterier står samtidigt inför utmaningar vad gäller resursutarmning (IEA, 2023; IRENA, 2022). Natriumjonbatterier är en lovande teknik för ESS-marknaden, som förväntas uppta 21 % av försäljningsmarknaden till 2030. Vilket skulle motsvara en efterfrågan på cirka 50 GWh natriumjonceller till 2030. De viktigaste drivkrafterna för en förmodad ökning av natriumbatterilagring är låga kostnader, överflödig tillgång på cellmaterial och förväntningar om att det ska vara ett säkrare och mer hållbart batteri. Litiumbatterier dominerar för närvarande energilagringsmarknaden, men har problem med etisk resursförsörjning och stigande mineralpriser, samtidigt som det finns en växande efterfrågan av energilagring. (BloombergNEF, 2023; IEA, 2023) Eftersom det finns sparsamt med information kring miljökonsekvenser av natriumbatteriproduktion (Liu et al., 2021; Peters et al., 2021) är syftet med den här studien att utvärdera miljöavtrycket av natriumjonbatterilagring. I studien utförs därför en livscykelanalys (LCA) på en bestämd natriumjoncell. Mer specifikt omfattar det att analysera det ekologiska avtrycket av 1 kWh producerad batterikapacitet, i ett cradle-to-gate-perspektiv. Resultaten presenteras dels som en fördelning av utsläppen över hela värdekedjan, inklusive material, transport och produktionspåverkan. Därtill visas en differentiering av cellmaterialets miljöpåverkan. Det berörda batteriet antas vara tillverkad i en giga scale produktion (>1 GWh årlig celltillverkning). Hypotetiskt antas tillverkningen placeras i Europa, men både en global och en lokal leveranskedja bedöms. I enlighet med europeiska initiativ finns det riktlinjer kallade PEFCR, som rekommenderar hur bedömningar av produkters miljöavtryck bör utföras. Det finns en specifik standard för miljöbedömning av batterier, vilken har eftersträvats i den här studien. I enlighet med rekommendationerna, innefattar den här studiens metod att utvärdera 16 miljöperspektiv, kallade EF2.0. De utsläppskategorier (EF2.0) som presenteras som huvudresultat är Climate Change (total), Acidification, Resource Use (fossils), Resource Use (minerals & metals), och Particulate Matter, eftersom dessa enligt PEFCR anses vara relevanta för just batterier. (European Commission and ReCharge, 2018) Det bör understrykas att den här studie har sitt huvudfokus på att analysera EF2.0 Climate Change (total), med målet att identifiera åtgärder för hur koldioxidavtrycket orsakat av batteriets livscykel kan minskas. För de 16 miljökategorierna, har ett natriumbatteris nuvarande läge ”current state scenario” satts i fokus. Utöver det presenteras ett ”decarbonized scenario” för EF2.0 Climate Change (total). För ”current state”-scenariot görs en jämförelse med ett litiumbatteri från industrin, vilket produceras med fossilfri energi. Därmed skapas förståelse för hur natriumbatteriets miljöpåverkan skiljer sig från det lågfossilintensiva litiumjoncellen. Både natrium- och litiumcellerna som ingår i jämförelsen har som avsikt att användas för energilagringssystem (ESS). Gällande resultatet av de 16 miljökategorierna är det tydligt att katoden är den främsta källan för utsläpp, följt av elektrolyten och anoden. I ”decarbonized scenario” illustreras därtill att om vissa specifika åtgärder implementeras i värdekedjan, skulle det kunna minska natriumbatteriers koldioxidutsläpp med potentiellt mer än hälften av vad som uppskattats idag. I nuläget pågår en utveckling och expansion av leveranskedjan för natriumbatteriproduktion (Rho motion, 2023), med en materialproduktion som börjar ta form. Samtidigt kan det i en snart framtid förväntas levereras natriumbatterier med högre energidensitet (Peters et al., 2021) och då skulle miljöpåverkan från natriumceller kunna sjunka avsevärt. Det centrala medskicket från den här studien är att resursanvändningen av mineraler och metaller drastiskt skulle minska i och med ett teknikskifte från litium- till natriumbatterier. Med de 16 miljöperspektiven i åtanke, är det övergripande resultatet att natriumceller orsakar mindre miljöskada jämfört med litiumteknik. Högst troligt, kan natriumceller i framtiden vara ett billigt och hållbart alternativ för energilagringssystem.

Micromobility has been on the rise lately with a vast catalogue of electric vehicles reaching the market. Electric scooters, mopeds, bikes, one-wheelers and other vehicles have become the norm in everyday life. Most of these vehicles are meant to replace smaller modes of transport such as ordinary bicycles and skateboards. They are designed to complete the last part of one’s commute or for travelling shorter distances. There is; however, a gap within this segment. There is currently no electric micromobility vehicle on the market that is small and lightweight that has a long enough range to compete with ordinary two-tonne cars for longer commutes. This project aims to remedy this by presenting a solution as well as building a prototype of said solution. The electric vehicle that was built for this project is foldable. The design, when folded, is intended to resemble a large, rollable, suitcase. The overall size of the vehicle when folded is only 700x500x400 mm. When unfolded, it is large enough to seat one person fully enclosed. The top speed is limited to 25 km/h and the maximum range per charge is above 100 km. The prototype weighs 29 kg and is able to carry 95 kg. This thesis proves that it is possible to make small and lightweight electric vehicles that can rival traditional cars when it comes to commuting. These vehicles would reduce emissions, congestion and the need for parking space while also being a cheaper alternative for the end user. / Mikromobilitet segmentet har växt avsevärt de senaste åren. En stor samling av olika elektriska fordon så som elskotrar, mopeder, cyklar och enhjulingar, med fler, har blivit en del av vardagen. De flesta av dessa fordon är skapta för att tilryggalägga kortare sträckor. De är ämnade att ersätta cyklar eller att färdas till fots. Det finns dock ingen produkt inom det här segmentet tillgänglig på marknaden som är designad för att kunna tillryggalägga längre sträckor medans den fortfarande är liten och bärbar. Ett sådant fordon presenteras i denna avhandling som lösning på detta problem. Dessutom konstruerades en prototyp av det föreslagna fordonet för att bevisa att det är möjligt att göra små elektriska fordon med lång räckvidd. Prototypen som tillverkades i denna avhandling är vikbar, vilket gör den lätt att transportera när den inte är i bruk. Hela fordonet viks ihop till en resväska som kan dras på bakhjulen. Den har en ihopvikt storlek av 700x500x400 mm, maxhastighet på 25 km/h och väger 29 kg. Detta fordon kan fullständigt innesluta en person när den är utfälld, bära upp till 95 kg och har en räckvidd på över 100 km per laddning. Fordon likt prototypen i denna avhandling kan hjälpa till med att minska utsläpp, minska behovet av parkeringsplatser och minska stockning på vägarna. Dessutom skulle ett sådant fordon också vara mer ekonomisk för slutanvändaren när det kommer till pendling jämfört med en traditionell bil.

Lithium-ion (Li-ion) batteries are amongst the most commonly used types in Electric (EVs) and Hybrid Electric (HEVs) Vehicles due to their high energy and power densities, as well as long lifetime. A battery is one of the most important components of an EV and hence it needs to be monitored and controlled accurately. The safety, and reliability of battery packs must then, be ensured by accurate management, control, and monitoring functions by using a Battery Management System (BMS). A BMS is also responsible for accurate real-time estimation of the State of Charge (SoC), State of Health (SoH) and State of Power (SoP) of the battery. The battery SoC provides information on the amount of energy left in the battery. The SoH determines the remaining capacity and health of a pack, and the SoP represents the maximum available power. These critical battery states cannot be directly measured. Therefore, they have to be inferred from measurable parameters such as the current delivered by the battery as well as its terminal voltage. Consequently, in order to offer accurate monitoring of SoC, SoH and SoP, advanced numerical estimation methods need to be deployed. In the estimation process, the states and parameters of a system are extracted from measurements. The objective is to reduce the estimation errors in the presence of uncertainties and noise under different operating conditions. This thesis uses and provides different enhancements to a robust estimation strategy referred to as the Smooth Variable Structure Filter (SVSF) for condition monitoring of batteries. The SVSF is a predictor-corrector method based on sliding mode control that enhances the robustness in the presence of noise and uncertainties. The methods are proposed to provide accurate estimates of the battery states of operation and can be implemented in real-time in BMS. To improve the performance of battery condition monitoring, a measurement-based SoC estimation method called coulomb counting is paired with model-based state estimation strategy. Important considerations in parameter and state estimation are model formulation and observability. In this research, a new model formulation that treats coulomb counting as an added measurement is proposed. It is shown that this formulation enhanced information extraction, leading to a more accurate state estimation, as well as an increase in the number of parameters and variables that can be estimated while maintaining observability. This model formulation is used for characterizing the battery in a range of operating conditions. In turn, the models are integral to a proposed adaptive filter that is a combination of the Interacting Multiple Model (IMM) concept and the SVSF. It is shown that this combined strategy is an efficient estimation approach that can effectively deal with battery aging. The proposed method provides accurate estimation for various SoH of a battery. Further to battery aging adaptation, measurement errors such as sensor noise, drift, and bias that affect estimation performance, are considered. To improve the accuracy of battery state estimation, a noise covariance adaptation scheme is developed for the SVSF method. This strategy further improves the robustness of the SVSF in the presence of unknown physical disturbances, noise, and initial conditions. The proposed estimation strategies are also considered for their implementation on battery packs. An important consideration in pack level battery management is cell-to-cell variations that impact battery safety. This study considers online battery parametrization to update the pack’s model over time and to detect cell-to-cell variability in parallel-connected battery cells configurations. Experimental data are used to validate and test the efficacy of the proposed methods in this thesis. / Thesis / Doctor of Philosophy (PhD) / To address the critical issue of climate change, it is necessary to replace fossil-fuel vehicles with battery-powered electric vehicles. Despite the benefits of electric vehicles, their popularity is still limited by the range anxiety and the cost determined by the battery pack. The range of an electric vehicle is determined by the amount of charge in its battery pack. This is comparable to the amount of gasoline in a gasoline vehicle’s tank. In consideration of the need for methods to address range anxiety, it is necessary to develop advanced algorithms for continuous monitoring and control of a battery pack to maximize its performance. However, the amount of charge and health of a battery pack cannot be measured directly and must be inferred from measurable variables including current, voltage and temperature. This research presents several algorithms for detecting the range and health of a battery pack under a variety of operating conditions. With a more accurate algorithm, a battery pack can be monitored closely, resulting in lower long-term costs. Adaptive methods for determining a battery’s state of charge and health in uncertain and noisy conditions have been developed to provide an accurate measure of available charge and capacity. Methods are then extended to improve the determination of state of charge and health for a battery module.

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京都大学 / 新制・課程博士 / 博士(工学) / 甲第24108号 / 工博第5030号 / 新制||工||1785(附属図書館) / 京都大学大学院工学研究科物質エネルギー化学専攻 / (主査)教授 安部 武志, 教授 作花 哲夫, 教授 阿部 竜 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DGAM

In this exploration of the human battery interface, the way in which battery information and notifications effect interaction are analyzed through two small scale studies and a design proposal which is then user tested. With the first study, an attempt is made to gauge user’s feelings toward the current battery information display on their smartphones through a brief online questionnaire. Participants who were selected for further study installed battery monitoring software on their devices and shared the resulting data. This data was then analyzed and some usage patterns were extrapolated. After surveying current market solutions and research in the field, design opportunities were explored and a final design proposal was created and tested with possibilities for further applications being discussed.