In diesem Beitrag wird ein neuer Ansatz zur Modellierung von Lithium-Ionen-Zellen vorgestellt, bei dem neben einem Modell zur Beschreibung des Nominalverhaltens der Zelle ein Unbestimmtheitsmodell parametriert wird, welches die unvermeidbare Abweichung zwischen dem Nominalmodell und dem tatsächlichen Zellverhalten quantifiziert. Für diese Modellbeschreibung wird ein neuer Algorithmus zur Ladezustandsdiagnose entwickelt, der anstelle eines einzelnen (fehlerbehafteten) Wertes für den Ladezustand ein Vertrauensintervall angibt sowie Artefakte im zeitlichen Verlauf des geschätzten Ladezustandes vermeidet. Die Eigenschaften der Ladezustandsschätzung werden an einer Lithium-Ionen-Zelle und einem Einsatzszenario aus dem automobilen Bereich demonstriert. / In this paper, a new approach to modeling lithium ion cells is presented. In addition to a model that describes the nominal behavior of the cell, an uncertainty model is parameterized which quantifies the unavoidable difference between the nominal model and the true system behavior. For this model description a new algorithm for state of charge estimation is developed, which provides a confidence interval instead of a single unreliable value for the state of charge and avoids artifacts in the progression of the estimated state of charge over time. The properties of the state of charge estimation are demonstrated on a lithium-ion cell in an automotive application scenario.

Lithium-ion batteries (LIB) represent a promising energy storage solution in the pursuit of electrification to combat climate change. In order for LIBs to be used across different industries, they have to be commercially viable. The viability for manufacturing LIBs at scale is increasing, with manufacturing costs decreasing 89% in the last ten years. However, the LIB manufacturing process is complex and can generate large amounts of scrap due to various non-conformities (NCs). Therefore, to further increase the ability to manufacture high-quality LIBs at scale, it is crucial to minimize the occurrence of NCs by understanding their root causes. This thesis examines the characteristics of one of the non-conformities occurring in the electrode coating process, namely the formation of craters on the coated surface of the anode electrode. The thesis was conducted at Northvolt Labs using a DMAIC approach to establish relationships between various process parameters and the formation of craters in two processes, coating, and its precursor process, slurry mixing. Utilizing the data models linear regression, CART regression, regularized linear regression, and a slurry experiment, process parameters and characteristics that affect crater formation were identified. Firstly, from the data models, it was distinguished that the speed of the supply pump used in transferring the slurry from the supply tank to the slot die, and the pressure in the filter pump, have the largest effect on crater formation. Further, the time that the slurry spends in storage, i.e. from a completely mixed slurry batch to it being applied in coating, affects crater formation. In this case, the longer the slurry is stored, the more craters are found. Another notable result is that refilling the coating supply tank induces crater formation. The mentioned results indicate that the various stages of slurry transfer undertaken before coating can result in advantageous conditions for craters to form. Moreover, it was discovered that changes in the loading level of the coated anode surface can indicate crater formation. The slurry experiment discovered that by contaminating the slurry with lubricant grease, NCs with similar characteristics to the crater could be generated. While not likely related to craters, this result provides valuable insights for slurry contamination. In addition to the data models and experiments, actions to facilitate future statistical analysis investigations are proposed. This thesis also proposes actions that can be undertaken to potentially mitigate the formation of craters. Suggested actions include methods to investigate the optimal storage time of the slurry before used in coating. Further, we recommend that the coating process should be monitored through the use of control charts on the loading level measurements of the coated surface. Consequently, large changes in loading level can be detected, entailing potential crater formation. We also propose adding lubricant grease as a potential risk in the PFMEA Northvolt uses for process risk evaluation. This recommendation is also complemented with suggested actions on how to handle the risks of lubricant grease contamination. / Användandet av litiumjonbatterier (LIB) som energilagring är en potentiell lösning för omställning till ett elektrifierat samhälle. Tillverkningsprocessen för LIBs är dock komplex och har en tendens att generera stora mängder kassationer på grund av olika typer av defekter. Denna studie ämnar att undersöka egenskaperna hos en av defekterna som kallas krater som kan förekomma i en av delprocesserna för litiumjonbatteritillverkning, elektrodbeläggning, där batteriets elektroder skapas genom att en blandning av aktiva material appliceras på en metallfolie. Kratern förekommer som en cirkulär form på den belagda ytan av anodelektroden. Studien genomfördes hos batteritillverkaren Northvolt Labs och använde en struktur enligt DMAIC cykeln. Syftet med studien var att fastställa samband mellan olika processparametrar och kraterformation för två olika processer, elektrodbeläggning och dess föregångare, framställning av den aktiva materialblandningen. Genom att använda datamodellerna linjär regression, CART-regression, en regulariserad linjär regression  samt ett experiment kunde processparametrar och egenskaper som påverkar kraterbildningen etableras. Resultaten från datamodellerna indikerar att varvtalet i pumpen som tillför ytbeläggningsmaskinen med den aktiva materialblandningen samt trycket i filterpumpen har den största effekten på kraterbildning. Vidare så påverkar tiden som den aktiva materialblandningen lagras innan den används i beläggningsprocessen. Resultaten indikerar att ju längre tid en aktiv materialblandning lagras, desto mer kraterbildning. Samtliga resultat som nämnts ovan anvisar att de olika stadier den aktiva materialblandningen överförs bland olika behållare och verktyg kan ge upphov till kraterbildning. Ytterligare resultat från datamodellerna indikerar att en minskad tjocklek av den belagda ytan, mätt med enheten g/cm2, kan påvisa när kratrar uppstår. Detta resultat kan härledas till att kratrarna orsakar en nedåtbuktning i den belagda ytan. Utifrån experimentet med den aktiva materialblandningen kunde det fastlås att kraterliknande defekter kunde genereras genom att kontaminera blandningen med smörjfett. Dessa defekter är sannolikt inte besläktade med kratern, men dess uppkomst ger värdefulla insikter hur kontaminering kan påverka kvaliteten på den belagda ytan. Utöver resultat från datamodellerna och experimentet så presenterar även denna studie förslag på hur framtida undersökningar av statistisk karaktär kan förbättras. Studien föreslår också konkreta åtanganden som kan genomföras med syfte att reducera kraterbildning. Detta inkluderar hur ett projekt med syfte att fastslå den optimala lagringstiden för den aktiva materialblandningen innan den används i ytbeläggningsprocessen kan utformas. Vidare rekommenderas att ytbeläggningsprocessen övervakas med hjälp av att upprätta styrdiagram för ytbeläggningens nivåförändringar. Följaktligen kan stora förändringar i ytbeläggningens jämnhet detekteras, vilket kan vara en indikator på kraterbildning. Studien rekommenderar också att tillägga kontaminering av smörjfett i den aktiva materialblandningen som en potentiell risk i Northvolts PFMEA. Denna rekommendation kompletteras även med förslag på åtanganden som kan tas för att hantera risken för kontaminering av smörjfett.

Wind resources are highly intermittent and fluctuant, making wind turbines less reliable and the unstable power output will affect grid stability and security. This paper presents an idea of integrating the solar PV plant and energy storage system into an existing wind project, project Rödene in Gothenburg. The hybrid renewable system, which consists of two or more renewable energy sources, is considered the renewable energy development trend. An economic analysis of a 1.2 MW PV plant, 5 MW lithium-ion battery storage system and 300 kg hydrogen fuel cell storge system are assessed in terms of LCOE and LCOS of plants. The revenue stream is discussed separately, consisting of electricity tariff, ancillary services and energy arbitrage. The results show that both PV plant and energy store systems are unprofitable. When the PV panel cost is reduced more than 30% and the annual production increases at least 30%, the LCOE of the PV plant arrives at the break-even point. Also result shows the hydrogen fuel cell energy storage system is too expensive of commercial use, and the battery energy storage system has a high potential of profitable if the ancillary service in Sweden is well organized in the future

京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第18981号 / 工博第4023号 / 新制||工||1619(附属図書館) / 31932 / 京都大学大学院工学研究科材料工学専攻 / (主査)教授 松原 英一郎, 教授 邑瀬 邦明, 教授 宇田 哲也 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DGAM

著作権、出典、利用制限の表示を出版社より求められている。 / 京都大学 / 0048 / 新制・課程博士 / 博士(エネルギー科学) / 甲第19824号 / エネ博第330号 / 新制||エネ||66(附属図書館) / 32860 / 京都大学大学院エネルギー科学研究科エネルギー基礎科学専攻 / (主査)准教授 高井 茂臣, 教授 萩原 理加, 教授 佐川 尚 / 学位規則第4条第1項該当 / Doctor of Energy Science / Kyoto University / DGAM

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Mariestad municipality participated in a global competition to become Volvo’s site for a new lithium-ion battery factory. The competition was between eleven different countries and three different locations in Sweden. Aer declaring Mariestad and the site Korstorp as winners, extensive surveys of the site were initiated during which they did a rare find of the protected species the great crested newt. However, Volvo is still planning on going through with building the factory the way they planned, which implies asphalting an area of 140-150 ha and constructing a box like factory of one or two floors. The newts are now under great threat and will have to be moved in order to make room for the factory. Building battery factories is something we strive for on a global scale, but what happens when global sustainability opposes local? In the example of the battery factory in Mariestad Agenda 2030’s sustainable development goals biodiversity and economic growth seem to be in opposition to each other and here it becomes clear that the value of humans and non-humans are different. How are we to remedy the unequal distribution of power and how can we turn the conflict zone in Korstorp into a zone of diplomacy? The convention of the rights of the child became Swedish law in 2020 and here it is relevant taking a look at article 12, which says; “All children have the right to express their opinions, adults shall listen and consider the children’s opinions”. The children are our future and they have to live with our choices. Building in a sustainable manner implies listening to who will be affected. The society’s measurement of success needs to be altered from economic growth to one which everybody has the right to be part of. To reach that place we have to practice at an early age to think and act in a democratic manner. If children feel as if they have been heard they could come to appreciate democratic processes in which they trust their ability to alter the society and feel obligated towards it. Furthermore, the unlimited imagination of children and the fact that they are not yet indoctrinated in the routines and customs of our society might bring the innovation needed to create a new kind of factory in symbiosis with the local environment.

Electric vehicles contain hundreds of high-energy density lithium-ion batteries. The crashworthiness of these vehicles can be improved by better understanding the response of these batteries in an event of an accident or abusive loads. These loads can induce short-circuit and thermal runways in extreme cases. Therefore, an efficient finite element model of a battery that can precisely predict the coupled multi-physics behavior of a cell in a real-world application is desired. This investigation incorporates detailed and homogenized multi-physics modeling of various form factors of lithium-ion batteries. In the first two chapters of this thesis, a multi-physics homogenized model of a pouch cell was developed and validated in a wide range of multi-disciplines of the battery. In contrast to other similar models described in the literature, which are only applicable in certain scenarios, this model has a much broader range of applications due to the innovative techniques developed for material calibration and cell modeling. In addition, due to the homogenized nature and computational cost efficiency of this technique, the developed model has significance in the crashworthiness analysis of battery packs and electric vehicles where hundreds of these batteries exist. In the final chapter, a detailed layered model of an 18650 cylindrical cell was developed. Component and cell-level tests were performed on the cell to calibrate the material properties and extract the geometries of all the components of the cell. This model is the first of its kind that precisely predicts the load-displacement response and shape of deformation in various loading scenarios. This developed model has crucial importance in the safety assessment of the batteries by providing insight into the sequence of deformation of the internal layers and components and their interplay during mechanical abuse loadings. Overall, the two developed models in this thesis provide battery-related industries with a tool to improve the safety of future electrified industries. / Mechanical Engineering