Li-ion batteries have gained great popularity among researchers and practitioners as an environmentally friendly energy storage solution for more environmentally friendly electric vehicles (EVs). However, because of the increased demand for Li-ion battery-powered EVs, and some issues with battery design, legislation, collection and sorting, recycling, and material recovery, achieving sustainable mobility through the circularity of Li-ion batteries is a major challenge. This study aims to identify the challenges as well as develop strategies for enhancing the circularity of Li-ion batteries in Sweden. Following a systematic literature review, two primary research questions were investigated: 1) what are the current challenges and opportunities for the circular economy in lithium-ion battery end-of-life management? 2) how the circularity of LIBs in Sweden could be enhanced? This study employed PEST and SWOT analysis, as well as 11 interviews with industry experts and researchers are performed, to determine the strengths, weaknesses, opportunities, and threats in the circularity of lithium-ion batteries in Sweden. Following that, various strategies were developed to address the identified challenges and improve the circular economy of these batteries. Finally, the developed strategies are validated through expert interviews, and various recommendations are outlined. The study's findings are significant and can assist policymakers, investors, and industry professionals concerned with the circularity of lithium-ion batteries in developing appropriate decisions and better planning for the Swedish transportation sector.

京都大学 / 新制・課程博士 / 博士(工学) / 甲第23515号 / 工博第4927号 / 新制||工||1769(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 陰山 洋, 教授 作花 哲夫 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM

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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.

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Li-ion batteries (LIB) are used in many applications because of their high-power/energy density, long life cycling, and low self-discharge rate. The use of LIB continues to grow every day, and the necessity for proper safety standards grows as well. A key aspect for safe utilization of LIB is determining their safety and remaining useful life (RUL). Battery characteristics degrade over time under normal and extreme operating conditions and modeling the electrochemical processes can improve RUL estimations. Extreme operating conditions such as abnormal temperatures and charge/discharge rates are believed to exacerbate the rate of degradation. Li-ion batteries are also susceptible to mechanical damage, which may lead to an electrical short. In severe cases, mechanical damage causes a thermal run away, and possibly explosions or fires. In the event of a car accident, battery packs can be damage without an electrical short or immediate thermal run away. Currently, there is no reliable batt / Mechanical Engineering

Lithium ion (Li-ion) batteries have been identified as a promising solution to meet the increasing demands for alternative energy in electric vehicles (EVs) and hybrid electric vehicle (HEVs). This work describes experimental and numerical study of thermal management of battery module consisting of cylindrical Li-ion cells, with an emphasis on the use of active control to achieve optimal cooling performance with minimal parasitic power consumption. The major contribution from this work is the first experimental demonstration (based on our review of archival journal and conference literature) and the corresponding analysis of active thermal control of battery modules. The results suggest that the active control strategy, when combined with reciprocating cooling flow, can reduce the parasitic energy consumption and cooling flow amount substantially. Compared with results using passive control with unidirectional cooling flow, the parasitic energy consumption was reduced by about 80%. This contribution was achieved in three steps, which was detailed in this dissertation in chapters 2, 3, and 4, respectively. In the first step, an experimental facility and a corresponding CFD model were developed to capture the thermal behavior of multiple battery cells. Based on the experimental and CFD results, a reduced-order model (ROM) was then developed for active monitoring and control purposes. In the second step, the ROM was parameterized and an observer-based control strategy was developed to control the core temperature of battery cells. Finally, based on the experimental facility and the ROM model, the active control of a battery module was demonstrated. Each of these steps represents an important facet of the thermal management problem, and it is expected that the results and specifics documented in this dissertation lay the groundwork to facilitate further study. / Ph. D.

This dissertation is focus on the study of solid-electrolyte interphases (SEIs) on advanced lithium ion battery (LIB) anodes. The purposes of this dissertation are to a) develop a methodology to study the properties of SEIs; and b) provide guidelines for designing engineered SEIs. The general knowledge gained through this research will be beneficial for the entire battery research community.

Ce travail de thèse est centré sur l’étude de matériaux LiMPO4 (M=Fe, Mn, Co) et de leur évolution en cyclage (processus rédox et interfaces électrode / électrolyte) dans des accumulateurs Li-ion. Il a été mené essentiellement sur la base d’analyses en spectroscopie photoélectronique à rayonnement X (XPS) couplées à des tests électrochimiques. Une oxydation de surface du phosphate LiFePO4 a été mise en évidence lors d’une exposition à l’air de ce matériau avec la formation d’impuretés de surface type Fe2O3. Au plan structure électronique, l’analyse des bandes de valence des matériaux LiMPO4 (M=Fe, Mn, Co) a notamment permis, pour LiFePO4, la visualisation de l’électron spin down du niveau Fe 3d amenant la première preuve expérimentale de la configuration électronique particulière (3d↑)5(3d↓)1 de Fe2+dans ce matériau. Ce travail a également contribué à mieux comprendre l’influence de la température de fonctionnement ainsi que de la nature de l’électrode négative sur les mécanismes de vieillissement des accumulateurs Li-ion. Pour les accumulateurs LiFePO4 // Graphite, la comparaison d’interfaces solide/électrolyte distribuées spatialement a montré que le vieillissement se caractérisant par la perte de lithium actif pouvait être mis en parallèle avec une hétérogénéité de fonctionnement de l’électrode positive. Enfin, l’extension des travaux aux matériaux prometteurs d’électrode positive Li(FeMn)PO4 a révélé que le potentiel de travail de fin de charge plus élevé pour le phosphate mixte, comparativement à LiFePO4, résultait dans une réactivité accrue vis-à-vis de l’électrolyte dont les conséquences ont été analysées. / This thesis is focused on the study of LiMPO4 (M = Fe, Mn, Co) materials and on their evolution upon cycling (redox process end electrodes / electrolyte interfaces) in lithium ion cells. It is based on X-Ray Photoelectron Spectroscopy (XPS) analyses coupled with electrochemical tests. During air exposure, a surface oxidation of phosphate LiFePO4 was observed that lead to the formation of surface impurities such as Fe2O3. Concerning electronic structure, the analysis of LiMPO4 (M=Fe, Mn, Co) materials valence spectra allowed for LiFePO4 the visualization of spin down Fe 3d electron which is the first experimental proof of the particular electronic configuration (3d↑)5(3d↓)1 of Fe2+ in this material. This work also allowed a better understanding of the effect of the working temperature as well as the nature of the negative electrode on Li-ion cells ageing mechanisms. For LiFePO4 // Graphite cell, the comparison of spatially distributed solid/electrolyte interfaces showed that ageing mechanisms, characterized by a loss of active lithium, could be associated with a heterogeneity of working of the positive electrode. In addition, the extension of these studies on new promising Li(FeMn)PO4 materials for positive electrode showed that higher working potential of mixed phosphate material compared to LiFePO4 material leads to a higher electrolyte reactivity which consequences were analysed.

Les éléments capables de former un alliage avec le lithium, tels que le silicium ou l’étain constituent des composés très prometteurs en tant que matériaux d’électrodes négatives pour la prochaine génération d’accumulateurs Li-ion. Un point important réside dans la compréhension des phénomènes se produisant aux interfaces électrode/électrolyte de ces nouveaux matériaux, la stabilité de la couche de passivation (SEI) se formant lors du cyclage en surface des électrodes constituant un élément primordial vis-à-vis des performances de la batterie. A côté des processus de lithiation et delithiation du matériau actif au cours du cyclage, il est important de mieux connaître la nature, la formation et l’évolution de la SEI de même que l’évolution des oxydes natifs de surface et la réactivité chimique de l’électrode au contact de l’électrolyte. Dans ce travail de thèse, pour mieux connaître et comprendre ces différents processus, nous avons développé une approche d'analyse non destructive à différentes profondeurs de la surface de matériaux d’électrodes. Les analyses ont été réalisées par spectroscopie photoélectronique à rayonnement X (XPS), la modification d’énergie du rayonnement incident permettant une variation de la profondeur d'analyse. Cette méthodologie a été utilisée pour sonder les phénomènes aux interfaces d’électrodes à base de silicium et d’étain. Les mécanismes se produisant lors du premier cycle électrochimique puis au cours d’un long cyclage d’électrodes à base de silicium cyclées avec le sel classique LiPF6 puis avec un nouveau sel très prometteur, LiFSI ont été analysés et discutés. L’étude a été étendue à un nouveau composé intermétallique à base d’étain: MnSn2. / Compounds forming alloys with lithium, such as silicon or tin, are promising negative electrode materials for the next generation of Li-ion batteries and an important issue is to better understand the phenomena occurring at the electrode/electrolyte interfaces of these materials. The stability of the passivation layer (SEI) is crucial for good battery performance and its nature, formation and evolution have to be investigated. It is also important to follow upon cycling alloying/dealloying processes, the evolution of surface oxides with battery cycling and the change in surface chemistry when storing electrodes in the electrolyte. The aim of this thesis is to improve the knowledge of these surface reactions through a non-destructive depth-resolved photoelectron spectroscopy analysis of the surface of new negative electrodes. A unique combination utilizing hard and soft-ray photoelectron spectroscopy allows by variation of the photon energy an analysis from the extreme surface to the bulk of the particles. This experimental approach was used to access the interfacial phase transitions at the surface of silicon or tin particles as well as the composition and thickness/covering of the SEI. Interfacial mechanisms occurring upon the first electrochemical cycle and upon long-term cycling of Si-based electrodes cycled with the classical salt LiPF6 and with a new promising salt, LiFSI were investigated as well as the interfacial reactions occurring upon the first cycle of an intermetallic compound MnSn2 were studied.