Data-driven prediction of battery health has gained increased attention over the past couple of years, in both academia and industry. Accurate early-stage predictions of battery performance would create new opportunities regarding production and use. Using data from only the first 100 cycles, in a data set of 124 cells where lifetimes span between 150 and 2300 cycles, this work combines parametric linear models with non-parametric Gaussian process regression to achieve cycle lifetime predictions with an overall accuracy of 8.8% mean error. This work presents a relevant contribution to current research as this combination of methods is previously unseen when regressing battery lifetime on a high dimensional feature space. The study and the results presented further show that Gaussian process regression can serve as a valuable contributor in future data-driven implementations of battery health predictions. / Datadriven prediktion av batterihälsa har fått ökad uppmärksamhet under de senaste åren, både inom akademin och industrin. Precisa prediktioner i tidigt stadium av batteriprestanda skulle kunna skapa nya möjligheter för produktion och användning. Genom att använda data från endast de första 100 cyklerna, i en datamängd med 124 celler där livslängden sträcker sig mellan 150 och 2300 cykler, kombinerar denna uppsats parametriska linjära modeller med ickeparametrisk Gaussisk processregression för att uppnå livstidsprediktioner med en genomsnittlig noggrannhet om 8.8% fel. Studien utgör ett relevant bidrag till den aktuella forskningen eftersom den använda kombinationen av metoder inte tidigare utnyttjats för regression av batterilivslängd med ett högdimensionellt variabelrum. Studien och de erhållna resultaten visar att regression med hjälp av Gaussiska processer kan bidra i framtida datadrivna implementeringar av prediktion för batterihälsa.

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.

No description available.

No description available.

<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.

The energy crisis and environmental pollution have become increasingly prominent in recent years. Lithium batteries have attracted extensive attention due to their high energy density, safety, and low pollution. To further study how the battery works, it is necessary to establish an accurate model conforming to the battery characteristics. As the core function of a battery management system(BMS), accurate state of charge(SoC) estimation dramatically improves battery life and performance. This thesis selects a ternary lithium battery in the centre for advanced life cycle engineering(CALCE) dataset for a study of cell modeling and SoC estimation. The second-order Thevenin equivalent circuit model is selected as the cell model due to a trade-off between model complexity and accuracy. The parameters to identify include OCV, internal ohmic resistance, polarized internal resistance and capacitance. They were obtained with the MATLAB toolbox at various SoC state points under different temperatures. The ‘terminal voltage comparison’ method is utilized to verify the identification's accuracy. The simulation results turn out to be satisfactory. Then cell SoC can be estimated after cell modeling. First, the principles of the Coulomb counting method, OCV method and EKF method are analyzed. The state space equations required in SoC estimation are determined by discretizing the non-linear equivalent circuit model. The simulation results are compared with the experimental results in the HPPC discharge experiment. Furthermore, the robustness of the EKF algorithm is further investigated. The results prove that the EKF algorithm has high precision, fast convergence speed and strong anti-interference capability. Last but not least, the research on battery pack SoC estimation was continued. How to expand a single cell into a battery pack is analyzed, including aggregating cells into a pack and scaling a cell model to a pack. In addition, battery pack SoC is individually estimated by the 'Big cell' method and 'Short board effect' method. The result is not so good, indicating that further work can be done to improve the SoC estimation accuracy. / Energikrisen och miljöföroreningarna har blivit allt mer framträdande de senaste åren. Litiumbatteri har väckt stor uppmärksamhet på grund av sin höga energitäthet, säkerhet och låga föroreningar. För att ytterligare studera hur batteriet fungerar är det nödvändigt att etablera en exakt modell som överensstämmer med batteriets egenskaper. Som kärnfunktionen hos BMS förbättrar noggrann SoC-uppskattning dramatiskt batteriets livslängd och prestanda. Denna avhandling väljer ett ternärt litiumbatteri i CALCE-datauppsättningen för forskning. Dessutom slutförs cellmodellering och SoC-uppskattning baserat på det. Den andra ordningens Thevenins ekvivalenta kretsmodell väljs som cellmodell på grund av en avvägning mellan modellens komplexitet och noggrannhet. Parametrarna som måste identifieras inkluderar OCV, intern ohmsk resistans, polariserad intern resistans och kapacitans. De erhölls med MATLAB-verktygslådan vid olika SoC-tillståndspunkter under olika temperaturer. Metoden "terminalspänningsjämförelse" används för att verifiera identifieringens noggrannhet. Simuleringsresultaten visar sig vara tillfredsställande. Sedan kan cell SoC uppskattas efter cellmodellering. Först analyseras principerna för Coulomb-räknemetoden, OCV-metoden och EKF-metoden. Tillståndsrymdsekvationerna som krävs vid SoC-uppskattning bestäms genom att diskretisera den icke-linjära ekvivalenta kretsmodellen. Simuleringsresultaten jämförs med de experimentella resultaten i HPPC-utsläppsexperimentet. Dessutom, robustheten hos EKF-algoritmen undersöks ytterligare. Resultaten bevisar att EKF-algoritmen har hög precision, snabb konvergenshastighet och stark anti-interferensförmåga. Sist men inte minst fortsatte forskningen kring SoC-uppskattning av batteripaket. Hur man expanderar ett enskilt batteri till ett batteripaket analyseras, inklusive aggregering av celler till ett paket och skalning av en cellmodell till ett paket. Dessutom uppskattas batteripaketets SoC individuellt med "Big cell"-metoden och "Short board effect"-metoden. Resultatet är inte så bra, vilket indikerar att ytterligare arbete kan göras för att förbättra SoC-uppskattningens noggrannhet.

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>

No description available.

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.