Over the last few decades, rechargeable lithium-ion batteries have been extensively used in portable instruments due to their high energy density and low self-discharge rate. Recently, lithium-ion batteries have emerged as the most promising candidate for electric vehicles and stationary energy storage. However, the maximum energy that lithium-ion batteries can store decreases as they are used because of various irreversible degradation mechanisms. Lithium-ion batteries are complex systems to understand, and various processes and their interactions are responsible for the degradation over time. The mechanical integrity and stability of the electrode layers inside the battery highly influence the battery performance, which makes it a necessity to characterize the mechanical behavior of electrode active layers for mesoscopic and macroscopic level modeling. In papers 1 and 2, the macroscopic mechanical behavior of active layers in the electrodes is investigated using U-shape bending tests. The active layers are porous and a different tensile and compressive behavior is captured by performing tests on single side coated dry specimens. The experiments reveal that the active layer is stiffer in compression as compared to tension. The compressive stiffness increases with bending strain whereas the tensile stiffness is almost independent of the bending strain. A very low value of modulus of the active layer (1-5 GPa) is measured in comparison to the metal foils (70-110 GPa) and the active particles (50-200 GPa) which shows that the electrode properties are governed majorly by the binders present in the active layers.  The time-dependent and hysteresis effects are also captured by the method which circumvents the flaws of many other test methods presented in the literature.   In paper 3, we present a multiscale homogenization method that couples mechanics and electrochemistry at the particle, electrode, and battery scales. The active materials of lithium-ion battery electrodes exhibit volume change during lithium intercalation or deintercalation. A lithium concentration gradient develops inside particles, as well as inside the active layer. The developed stress due to deformations further affects solid diffusion.  We utilized models that have already been developed to couple particle and electrode layer levels. The mechanical coupling between the electrode and the battery level is achieved by homogenization of the layered battery using three-dimensional laminate theory.  By application of the model, we demonstrate that the stresses on all considered scales can be predicted from the homogenized model. It is furthermore demonstrated that the effects of external battery loadings like battery stacks, casings, and external pressure can be captured by the model. The model can also capture the effect of various electrochemical cycling rates and mechanical parameters like layer thicknesses, stiffnesses, and swelling properties. The presented multi-scale model is fast, accurate and the efficiency of the method is demonstrated by comparisons to detailed finite element computations where each layer is individually modeled.

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Philosophiae Doctor - PhD (Chemistry) / Lithium ion capacitors are new and promising class of energy storage devices formed from a combination of lithium-ion battery electrode materials with those of supercapacitors. They exhibit better electrochemical properties in terms of energy and power densities than the above mentioned storage systems. In this work, lithium manganese oxide spinel (LiMn2O4; LMO) and lithium manganese phosphate (LiMnPO4; LMP) as well as their respective nickel-doped graphenised derivatives (G-LMNO and G-LMNP) were synthesized and each cathode material used to fabricate lithium ion capacitors in an electrochemical assembly that utilised activated carbon (AC) as the negative electrode and lithium sulphate electrolyte in a two-electrode system. The synthetic protocol for the preparation of the materials followed a simple solvothermal route with subsequent calcination at 500 - 800 ?C. The morphological, structural and electrochemical properties of the as prepared materials were thoroughly investigated through various characterisation techniques involving High resolution scanning electron microscopy (HRSEM), High resolution transmission electron microscopy (HRTEM), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, X-ray diffraction (XRD), Small-angle X-ray scattering (SAXS), Electrochemical impedance spectroscopy (EIS), Cyclic voltammetry (CV) and Galvanostatic charge/discharge.

Indiana University-Purdue University Indianapolis (IUPUI) / Computational analysis of lithium ion batteries has been improved since Newman and et al. suggested the porous electrode theory. It assumed the electrode as a simple structure of homogeneous spherical particles. Bruggeman relationship which characterizes porous material by a simple equation was adopted in the homogeneous electrode model instead of the electrode morphology. To improve the prediction of a cell performance, the numerical analysis requires the realistic microstructure of the cell. Based on the experimentally determined microstructure of the positive and negative electrodes of a lithium ion battery (LIB) using x-ray micro/nano-CT technology, three dimensional (3D) simulations have been presented in this research. Tortuosity of the microstructures has been calculated by a linear diffusion equation to characterize the 3D morphology. The obtained tortuosity and porosity results pointed out that the Bruggeman relationship is not sufficiently estimate the tortuosity by the porosity of electrodes. We studied the diffusion-induced stress numerically based on realistic morphology of reconstructed particles during the lithium ion intercalation process. Diffusion-induced stresses were simulated at different C rates under galvonostatic conditions and compared with spherical particles. The simulation results showed that the intercalation stresses of particles depend on their geometric characteristics. The highest von Mises stress and tresca stress in a real particle are several times higher than the stresses in a spherical particle with the same volume. With the reconstructed positive electrode structure, local effects in the LIB cathode electrode during galvanostatic discharge process have been studied. The simulation results reported that large current density usually occurs at the joints between cathode active material particles and in the small channels in electrolyte, which will generate high electric joule power. By using the 3D real image of a LIB cathode electrode, numerical simulation results revealed that the spatial distribution of variable fields such as concentration, voltage, reaction rate, overpotential, and etc. in the cathode electrode are complicated and non-uniform, especially at high discharge rates.

Syfte – Syftet med studien är att Identifiera förbättringsmöjligheter och kritiska faktorer genom att studera returflödet för litiumjonbatterier ur ett miljöperspektiv. Genom att studera returflödet för litiumjonbatterier kan det hjälpa till att ta reda på hur flödet kan se ut för att minimera miljöpåverkan. Detta görs för att bidra med kunskap till återvinningsbranschen om hur returflödet för litiumjonbatterier ser ut idag och hur det förbättras i framtiden.  För att uppnå syftet med studien har två frågeställningar tagits fram:  [1] Hur kan returflödet för litiumjonbatterier förbättras ur ett miljöperspektiv?  [2] Vilka kritiska faktorer kan beaktas vid utformningen av returflödet för litiumjonbatterier?  Metod – Studien har utförts som en fallstudie på ett av Sveriges största återvinningsbolag. Forskarna startade med en förstudie i form av en ostrukturerad observation på fallföretagets återvinningsstation. Vidare hölls en ostrukturerad workshop med den strategiska logistikchefen och en affärsutvecklare inom batterier på fallföretaget. Förstudien gav forskarna en fördjupad kunskap i det aktuella ämnet och därpå kunde ett teoretiskt ramverk byggas upp för att stödja studien. För att uppfylla studiens syfte och besvara frågeställningarna har kvalitativ datainsamling i form av tre intervjuer och dokumentationsstudie utförts. För att besvara studiens syfte har det teoretiska ramverket och den insamlade empirin analyserats och ställts mot varandra.  Resultat – Returflödet för litiumjonbatterier kan förbättras genom att utforma ett navsystem. Navsystemet innebär i praktiken att det kan anläggas mellanlagringstationer där litiumjonbatterierna plockas isär och djupurladdas. Mellanlagringen minimerar avståndet som litiumjonbatterierna behöver fraktas innan de är djupurladdade vilket bidrar till att enklare emballage kan användas och ökad fyllnadsgrad vid transport. Enklare emballage och ökad fyllnadsgrad bidrar till att minska miljöpåverkan i returflödet för litiumjonbatterier. En optimeringsmodell kan användas för att minimera antalet tonkilometer som krävs för att transportera litiumjonbatterier mellan flödets alla delar. Vidare identifierades kritiska faktorer som påverkar returflödets utformning. De kritiska faktorerna som identifierades var:  - Ökade volymer  - Farligt gods  - Skadade batterier  - Nytt forskningsområde  - Osäkerhet i varifrån LIB kommer in i flödet  Studien har bidragit med kunskap för återvinningsbranschen genom att besvara frågeställningarna och därför anses studiens syfte uppnått.  Implikationer – Studiens resultat kan användas av återvinningsbranschen för att förstå returflödet av litiumjonbatterier och hur flödet kan förbättras. Resultatet kan även ge indikationer på vilka kritiska faktorer som behöver tas hänsyn till vid utformning av returflödet för litiumjonbatterier. Studien bidrar med kunskap till vidare forskning inom området för hanteringen av litiumjonbatterier.  Begränsningar – Det kan ifrågasättas om studien kan generaliseras för alla parter i återvinningsbranschen då studien bygger sitt resultat på endast ett fall. Studiens ämne är outforskat och därmed inte helt okomplicerat att studera på grund av brist på kunskap och tidigare forskning. Det studerade ämnet består av processer som inte finns på plats idag och således kan studiens resultat inte valideras då scenariot är en bit bort i framtiden. / Purpose – The purpose of the study is to identify opportunities for improvement and critical factors by studying the return flow of lithium-ion batteries from an environmental perspective. By investigating the return flow of lithium-ion batteries, it can help to find out what the flow might look like to minimize the environmental impact. This is done to contribute knowledge to the recycling industry about what the return flow for lithium-ion batteries looks like today and how it can be improved in the future.  To achieve the purpose of the study, two research questions have been raised:  [1] How can the reverse logistics for the collection of lithium-ion batteries be improved from an environmental perspective?  [2] What critical factors can be considered in the design of reverse logistics for lithium-ion batteries?  Method – The study was carried out as a case study at one of Sweden's largest recycling companies. The researchers started with a pilot study in the form of an unstructured observation at the case company recycling station. Furthermore, an unstructured workshop was held with the strategic logistics manager and a battery business developer at the case company. The pilot study gave the researchers an in-depth knowledge of the current subject and then a theoretical framework could be built up to support the study. In order to fulfil the purpose of the study and answer the research questions, qualitative data collection in the form of three interviews and documentation studies has been performed. To answer the purpose of the study the theoretical framework and the collected empirical data have been analysed and set against each other.  Findings –The reverse logistics when collecting lithium-ion batteries can be improved by designing a hub and spoke system. The hub and spoke system are in practice that intermediate storage stations can be built where the lithium-ion batteries are disassembled and deep discharged. The intermediate storage minimizes the distance that the lithium-ion batteries need to be transported before they are deep discharged, which contributes to simpler packaging being used and an increased degree of filling during transport. Simpler packaging and an increased degree of filling help to reduce the environmental impact of the reverse logistics for lithium-ion batteries. An optimization model can be used to minimize the number of tonne-kilometres required to transport lithium-ion batteries between all parts of the flow. Furthermore, critical factors were identified that affect the design of the reverse logistics. The critical factors identified were:  - Growing volumes  - Dangerous goods  - Damaged batteries  - New phenomenon  - Uncertainty in where lithium-ion batteries come into the flow  The study has contributed knowledge for the recycling industry by answering the questions and therefore the purpose of the study is considered to have been achieved.  Implications – The results of the study can be used by the recycling industry to understand the reverse logistics of lithium-ion batteries and how the flow can be improved. The result can also give indications of which critical factors need to be considered when designing the return flow for lithium-ion batteries. The study contributes with knowledge to further research in the field of handling lithium-ion batteries.  Limitations – It can be questioned whether the study can be generalized for all parties in the recycling industry as the study bases its results on only one case. The subject of the study is unexplored and thus not completely uncomplicated to study due to lack of knowledge and previous research. The studied subject consists of processes that are not in place today and therefor the results of the study cannot be validated as the scenario is a bit far in the future.

Using alternating current in order to heat batteries at sub-zero temperatures is a method,which is investigated in-depth by an increasing number of study groups. The thesis considersthe resonance phenomenon with the intention to use alternating current amplificationand battery’s impedance in order to induce power dissipation inside the battery, and in thisway increase its temperature. A battery cell is thereby modelled as an impedance transferfunction, estimated from electrochemical impedance spectroscopy measurements, whichare taken for a LiNi 13Mn13Co13O2 cell. Note that at 1 kHz and room temperature (20 ◦C),the ohmic resistance of the selected cell amounts to only 0.76m. Five resonant circuitsare investigated and one of them is selected for further investigation, and as a basis for afilter design. The chosen resonant circuit lead to an LCL filter with current magnification.The experimental setup used for conducting practical experiments, offers the possibilityof operating the voltage source converter both as a Full-bridge and as a Half-bridge, withand without current control. For each possible configuration, an LCL filter and a currentcontroller are designed, taking into account the corresponding limitations in frequency,current and controller voltage. The filter design is based on a multiobjective optimizationmethod used to determine filter components that yield the highest gain value for everyconfiguration. The method minimizes two objective functions in order to find an optimalsolution. The first objective is the reversed absolute value of the gain, whereas thesecond one is the absolute impedance of the circuit, consisting of the filter and batterycells. The gain is thereby defined as the ratio between the induced cell current and thecurrent entering the circuit. The obtained results of the proposed method are experimentallyvalidated. Depending on how the filters were physically designed and taking intoaccount the corresponding voltage source converter configuration, gains of 16 were experimentallyachieved. Finally, the three investigated configurations are compared againstthe reference case (Half-bridge voltage source converter with current control and a singleinductor) regarding their power efficiencies. The power measurements showed that despitehigh obtained gains, the overall filter power losses remained approximately in thesame range, compared to the power losses of the reference case. This is due to the factthat stray resistances of the designed LCL filters easily reached values of around 40m,which hindered an efficient power transfer with the chosen voltage source converter andthe used battery cells. This further indicates the importance of building filters with lowstray resistances and in this thesis, it represents a primary source of improvement. / Användandet av växelströ m fö r att värma upp batterier är en metod som fö r närvarande undersö ks av ett flertal forskargupper. Detta examensarbete fokuserar kring hur resonans kan nyttjas fö r att ö ka strö mfö rstärkningen och, pådetta sätt, ö ka effektutvecklingen i batteriet (av LiNi1/3Mn1/3Co1/3O2-typ). Battericellens impedans modelleras som en ö verfö ringsfunktion vars parametrar estimerats från tidigare genomfö rda impedansspektroskopimätningar. Vid 1 kHz och rumstemperatur är den cellens ohmska resistansen endast 0.76 mΩ. Fem mö jliga resonanta kretsar har undersö kts och en av dem valts ut fö r vidare undersö kningar. The utvalda kretsen är ett LCL-filter med vilken strö mfö rstärkning åstadkoms. Den experimentella uppställningen, i vilken praktiska test har genomfö rts, medger mö jligheten att nyttja den tillhö rande omriktaren både som en helbrygga och en halvbrygga, med och utan strö mreglering. Fö r varje mö jlig omriktarkonfiguration har ett LCL-filter och en strö mreglering tagits fram, med hänsyn tagen till uppställningens begränsningar i termer av frekvens, strö moch dc-spänningsnivå. Filtren är framtagna med hjälp av en multiobjektiv optimering vilken åstadkommer hö gsta strö mfö rstärkning mö jlig fö r varje omriktare och strö mregleringsval. Metoden minimerar tvåfunktioner fö r att finna en optimal lö sning. Den fö rsta funktionen beskriver inversen påströ mfö rstärkningen och den andra lastens (bestående av filter och tillhö rande battericell) impedans absolutbelopp. Den resulterande ö har validerats experimentellt och en strö mfö rstärkningsnivåpå 16 uppnåddes. Slutligen har de olika konfigurationerna jämfö rts i termer av verknings-grad. De genomfö rda effektmätningarna visar att trots att hö ga strö mfö rstärkningsnivåer var mö jliga såresulterade de associerade filterfö rlusterna till liknande verkningsgrader fö r alla studerade konfigurationer. Resultaten understryker fö rdelarna med hö geffektiva filtervilka representerar en mö jlig väg fö r vidare undersö kningar.

<p>Lithium-Ion Batteries (Li-ion batteries or LIBs) have been extensively used in a wide variety of industrial applications and consumer electronics. Additive Manufacturing (AM) or 3D printing (3DP) techniques have evolved to allow the fabrication of complex structures of various compositions in a wide range of applications. </p> <p><br></p> <p>The objective of the thesis is to investigate the application of 3DP to fabricate a LIB, using a modified process from the literature [1]. The ultimate goal is to improve the electrochemical performances of LIBs while maintaining design flexibility with a 3D printed 3D architecture. </p> <p><br></p> <p>In this research, both the cathode and anode in the form of specifically formulated slurry were extruded into filaments using a high-temperature pellet-based extruder. Specifically, filament composites made of graphite and Polylactic Acid (PLA) were fabricated and tested to produce anodes. Investigations on two other types of PLA-based filament composites respectively made of Lithium Manganese Oxide (LMO) and Lithium Nickel Manganese Cobalt Oxide (NMC) were also conducted to produce cathodes. Several filaments with various materials ratios were formulated in order to optimize printability and battery capacities. Finally, flat battery electrode disks similar to conventional electrodes were fabricated using the fused deposition modeling (FDM) process and assembled in half-cells and full cells. Finally, the electrochemical properties of half cells and full cells were characterized. Additionally, in parallel to the experiment, a 1-D finite element (FE) model was developed to understand the electrochemical performance of the anode half-cells made of graphite. Moreover, a simplified machine learning (ML) model through the Gaussian Process Regression was used to predict the voltage of a certain half-cell based on input parameters such as charge and discharge capacity. </p> <p><br></p> <p>The results of this research showed that 3D printing technology is capable to fabricate LIBs. For the 3D printed LIB, cells have improved electrochemical properties by increasing the material content of active materials (i.e., graphite, LMO, and NMC) within the PLA matrix, along with incorporating a plasticizer material. The FE model of graphite anode showed a similar trend of discharge curve as the experiment. Finally, the ML model demonstrated a reasonably good prediction of charge and discharge voltages. </p>

Energy storage is crucial for intermittent renewable energy sources, electric vehicles, and portable devices. The continuously increasing energy consumption in these industries necessitates the enhancement of commercial lithium-ion batteries (LIB), especially regarding their safety and energy density. Historically, aqueous electrolytes were the norm in the battery industry. Prior to the development of lithium batteries, most commercially significant batteries used water as the solvent. In the past decade, "highly concentrated" electrolytes resurrected the notion of an aqueous lithium-ion battery (ALIB). Significant efforts have been made since then to comprehend the interfacial stability of these high-concentration electrolytes, and make them suitable for use in batteries especially high voltage ones. Another candidate for future batteries is All-Solid-State Batteries (ASSB) as they have the potential to double, or even triple, the energy density figures we currently achieve in LIBs mainly due to their ability to utilize lithium metal anode which has the highest specific capacity among anodes (3860 mAh g⁻¹), lowest reduction potential (-3.04 V vs SHE), and low density (0.53 g cm⁻³). This thesis first proposes a phenomenological model to describe the microstructure of aqueous electrolyte and the relation between their phase diagrams with ionic conductivity; highlighting a common correlation between the eutectic composition and peak ionic conductivity in conductivity isotherms. we then propose an empirical model correlating ionic conductivity with both molar concentration and temperature. The aim of this portion of the thesis is to provide an in depth understanding of aqueous electrolytes' physical properties in a way that can help researchers optimize the energy density and the cost of ALIBs. Moving further, the thesis presents two novel composite solid electrolytes (CSE) that were developed and fully characterized. Both of which were composed of the following four components; polyethylene oxide (PEO), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) salt, lithium lanthanum titanate (LLTO) perovskite inorganic ceramic and the polymer plasticizer succinonitrile (SN). The careful formulation of these CSEs was based on the trade-off between film forming ability and ionic conductivity. The optimized polymer rich CSE proved to have better characteristics when compared to its ceramic rich alternative. ASSBs employing both CSEs were successfully charged and discharged when coupled with lithium metal anode and in-lab prepared composite cathode. The developed thin and flexible CSEs could be utilized in small applications (Wh-KWh) such as in consumer electronics and flexible biomedical devices (e.g., pacemakers) or larger applications (kWh-MWh) such as in EVs and large format storage for the electrical grid.

Since their introduction in the late 20th century, lithium-ion batteries have become the leading battery technology for portable devices and electric vehicles due to their high energy density and rechargeability. However, the increasing demand for a longer battery life span is hindered by the fading of the battery’s charge capacity over prolonged use. This reduction in charge capacity stems from electrochemical and mechanical degradation of the battery cells. The main research focus in the literature has been on the chemical degradation of battery cells. However, the mechanical degradation also substantially contributes to the battery’s capacity degradation. Therefore, it is crucial to understand the mechanical properties of the battery cells to be able to mitigate mechanical degradation. The battery’s mechanical degradation stems from the electrode layers’ constituents. This thesis aims to model the positive electrode’s mechanical properties by recreating its granular microstructure using the discrete element method. In Papers 1 and 2, a discrete element method modelling framework is developed, which can reconstruct a positive electrode layer of a lithium-ion battery, simulate manufacturing processing steps, and determine the mechanical properties of the electrode layer. The framework uses two contact models, representing the positive electrode material in the form of particles and a binder agent, which gives the electrode layer its structural integrity. The framework is used to link the mechanical behaviour of the electrode particles and the binder agent to the mechanical behaviour of the entire electrode layer. The framework is able to capture the layer’s pressure sensitivity and relaxation behaviour, properties which have been displayed in the literature through experimental testing. / Sedan de introducerades i slutet av 1900-talet har litiumjonbatterier blivit den ledande batteriteknologin för portabla enheter samt elfordon på grund av deras höga energidensitet och återladdningförmåga. Den ökade efterfrågan på utökade batterilivslängder är dock hämmad av reduceringen av uppladdningskapacitet över längre användningstider. Denna reducering av laddningskapacitet kommer från elektrokemisk och mekanisk degradering av battericellerna. Det största forskningsintresset i litteraturen har varit på den kemiska degraderingen av battericellerna. Dock ger den mekaniska degraderingen ett betydande bidrag till batteriets kapacitetsdegradering. Därför är det viktigt att förstå battericellens mekaniska egenskaper för att kunna förhindra mekaniskdegradering. Batteriets mekaniska degradering beror på elektrodlagrets beståndsdelar. Denna avhandlings målsättning är att modellera den positiva elektrodens mekaniska egenskaper genom att återskapa dess granulära mikrostruktur med hjälp av diskret elementmetodik. I Artikel 1 och 2 utvecklades ett ramverk för modellering med användning av diskreta elementmetoden, vilket kan återskapa det aktiva lagret för en positiv elektrod, simulera tillverkningsprocesser, samt fastställa elektrodlagrets mekaniska egenskaper. Ramverket använder två kontaktmodeller som representerar det positiva elektrodmaterialet i form av partiklar samt ett bindemedel, som ger elektrodlagret dess strukturella integritet. Ramverket används för att undersöka hur de mekaniska egenskaperna för det hela elektrodlagret beror på egenskaperna för de aktiva partiklarna samt bindemedlet. Ramverket kan fånga lagrets tryckkänslighet samt dess relaxering, egenskaper som har påvisats i litteraturen genom experimentell provning. / <p>Qc240322</p>

The master's thesis is devoted to establish optimal parameters produced composites of iron oxide and carbon (FeOx/C) through the physicochemical study of the samples obtained for further use as anode materials of lithium-ion batteries (LIA). This interdisciplinary work was made in the laboratory of chemistry of compounds of rare-earth elements of the The Institute of Solid State Chemistry of the Ural Branch of the Russian Academy of Sciences as well as with the use of the equipment of the Ural Center for Shared Use «Modern nanotechnologies» of Ural Federal University named after the first President of Russia B. N. Yeltsin. / Магистерская диссертация посвящена установлению оптимальных параметров получения композитов из оксида железа и углерода (FeOx/C) посредством физико-химического исследования полученных образцов для дальнейшего использования в качестве анодных материалов литий-ионных аккумуляторов (ЛИА). Данная работа носит междисциплинарный характер и была выполнена в лаборатории химии соединений редкоземельных элементов ИХТТ УрО РАН, а также с использованием оборудования УЦКП «Современные нанотехнологии» УрФУ им. Б. Н. Ельцина.