Polyanionic compounds have been heavily investigated as possible electrode materials in lithium- and sodium-ion batteries. Chief among these is lithium iron phosphate (LiFePO4) which adopts the olivine structure and has a potential of 3.5 V vs. Li/Li+. Many aspects of ion transport, solid-solution behaviour and their relation to particle size in olivine systems are not entirely understood. Morphology, unit cell parameters, purity and electrochemical performance of prepared LiFePO4 powders were greatly affected by the synthetic conditions. Partially delithiated olivines were heated and studied by Mössbauer spectroscopy and solid-solution behaviour by electron delocalization was observed. The onset of this phenomenon was around 470-500 K in bulk material but in nanocrystalline powders, the onset of a solid solution was observed around 420 K. The isostructural manganese member of this family (LiMnPO4) was also prepared hydrothermally. Owing to the thermal instability of MnPO4, partially delithiated LiMnPO4 did not display any solid-solution behaviour. Phosphates based on the tavorite (LiFePO4OH) structure include LiVPO4F and LiFePO4(OH)1-xFx which may be prepared hydrothermally or by solid state routes. LiVPO4F is a high capacity (2 electrons/transition metal) electrode material and the structures of the fully reduced Li2VPO4F and fully oxidized VPO4F were ascertained. Owing to structural nuances, the potential of the iron tavorites are much lower than that of the olivines. The structure of Li2FePO4F was determined by a combined X-ray and neutron diffraction analysis. The electrochemical properties of very few phosphates based on sodium are known. A novel fluorophosphate, Na2FePO4F, was prepared by both solid state and hydrothermal methods. This material exhibited two two-phase plateau regions on cycling in a half cell versus sodium but displayed solid-solution behaviour when cycled versus lithium, where the average potential was 3.3 V. On successive cycling versus Li a decrease in the sodium content of the active material was observed, which implied an ion-exchange reaction occurred between the material and the lithium electrolyte. Studies of polyanionic materials as positive electrode materials in alkali metal-ion batteries show that some of these materials, namely those which contain iron, hold the most promise in replacing battery technologies currently available.

Compounds forming alloys with lithium, such as silicon or tin, are promising negative electrode materials for the next generation of Li-ion batteries due to their higher theoretical capacity compared to the current commercial electrode materials. An important issue is to better understand the phenomena occurring at the electrode/electrolyte interfaces of these new 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 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 PES (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 (soft X-ray) to the bulk (hard X-ray) 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 of Si-based electrodes cycled with the classical salt LiPF6 were investigated. The mechanisms of Li insertion (LixSi formation) have been illustrated as well as the formation of a new irreversible compound, Li4SiO4, at the outermost surface of the particles. Upon long cycling, the formation of SiOxFy was shown at the extreme surface of the particles by reaction of SiO2 with HF contributing to battery capacity fading. The LiFSI salt, more stable than LiPF6, improved the electrochemical performances. This behaviour is correlated to the absence of SiOxFy upon long-term cycling. Some degradation of LiFSI was shown by PES and supported by calculations. Finally, interfacial reactions occurring upon the first cycle of an intermetallic compound MnSn2 were studied. Compared to Si based electrodes, the SEI chemical composition is similar but the alloying process and the role played by the surface metal oxide are different.

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Vehicle design and control is an attractive area of research in that it embodies a convergence of societal need, technical limitation, and emerging capability. Environmental, political, and monetary concerns are driving the automotive industry towards sustainable transportation, manifested as increasing powertrain electrification in a gradual transition to fossil-free energy vectors. From an electrochemical degradation and control systems perspective, this transition introduces significant technical uncertainty. Initial indications are that the initial battery designs will have twice the required capacity due to degradation concerns. As the battery is a major contributor to the cost of these vehicles the over-sizing represents a significant threat to the ability of OEMs to produce cost-competitive vehicles. This potential barrier is further amplified when the combustion engine is removed and battery-electric or fuel-cell hybrid vehicles are considered. This thesis researches the application of model-based design for optimal design of fuel cell hybrid powertrains considering power source degradation. The intent is to develop and evaluate tools that can determine the optimal sizing and control of the powertrain; reducing the amount of over-sizing by numerically optimization rather than a sub-optimal heuristic design. A baseline hybrid fuel cell vehicle model is developed and validated to a hybrid fuel cell SUV designed and built at the University of Waterloo. Lithium-ion battery degradation models are developed and validated to data captured off a hybrid powertrain test stand built as part of this research. A fuel cell degradation model is developed and integrated into the vehicle model. Lifetime performance is modeled for four hybrid control strategies, demonstrating a significant impact of the hybrid control strategy on powertrain degradation. A plug-in variation of the architecture is developed. The capacity degradation of the battery is found to be more significant than the power degradation. Blended and All-electric charge-depleting hybrid control strategies are integrated and lifetime performance is simulated. The blended charge-depleting control strategy demonstrated significantly less degradation than the all-electric strategy. An oversized battery is integrated into the vehicle model and the benefit of oversizing on reducing the battery degradation rate is demonstrated.

The reversible electrochemistry and the superior gravimetric and volumetric energy storage capacities of lithium ion batteries (LIBs) have propelled them as the dominant power source for a range of portable electronic devices. Thin film LIBs are a class of LIBs that have been extensively used for powering Microelectromechanical systems devices, Radio-frequency Identification tags, biomedical sensors and several other low power electronic systems. Thin film electrodes and electrolytes are characteristic of short lithium ion diffusion paths and hence show fast charge/discharge rates. But the thin film battery technology has the major drawback of possessing low energy per footprint area. The three dimensional design for thin film LIBs has been proposed to improve electrode mass loading per footprint area thereby improving the energy delivered by the device. Hence there is interest in assembling the entire battery (current collectors, anode, electrolyte, and cathode) in a three dimensional (3D) nanostructured architecture. This thesis deals with the development and assembly of nanostructured three dimensional designs for Li ion battery components. Several template-based techniques have been used to fabricate nanostructured materials which serve as building blocks for the 3D energy storage devices. Firstly we have addressed the challenging task of fabricating conformal nanostructured polymer electrolytes around nanowire electrode material. The polymer coatings helped in controlling the secondary electrolyte interphase formation and hence in the improvement of cycling characteristics of the nanowire electrode material. We have also fabricated 3D current collectors with both ordered and disordered pore structure. Electrodes coated on 3D nanostructured current collectors showed improved rate capability and energy per footprint area. Finally, we have used a bottom up approach to assemble all essential components (anode, electrolyte, and cathode) of an electrochemical energy storage device onto a single nanowire, and have tested a parallel array of such nanowire devices for its electrochemical performance, hence demonstrating the ultimate miniaturization possible for energy storage devices.

In this thesis information received from a hybrid vehicle battery test equipment wasstructured and analyzed. This test equipment is currently placed on a fleet of Scaniatrucks with the purpose of emulating hybrid vehicle environment on battery cell level.A Microsoft Access database structure was set up in order to make it possible to savetest data in a structured way. In addition, Matlab scripts were made with the purposeof calculating cell aging from pulse- and capacity tests. Furthermore, drive cycleanalysis was performed looking at statistics for selected parameters. Data collectedfrom late October 2010 until beginning of July does not yet show any aging of the fieldtested battery cells regarding capacity loss or resistance increase. The internalresistance of the batteries was calculated to 2 to 4 milli ohm and the capacity wasfrom the tests found to be around 3 ampere hours. The energy efficiency, which wascalculated from pulse test data, shows an efficiency between 95 to 97%.

Vehicle design and control is an attractive area of research in that it embodies a convergence of societal need, technical limitation, and emerging capability. Environmental, political, and monetary concerns are driving the automotive industry towards sustainable transportation, manifested as increasing powertrain electrification in a gradual transition to fossil-free energy vectors. From an electrochemical degradation and control systems perspective, this transition introduces significant technical uncertainty. Initial indications are that the initial battery designs will have twice the required capacity due to degradation concerns. As the battery is a major contributor to the cost of these vehicles the over-sizing represents a significant threat to the ability of OEMs to produce cost-competitive vehicles. This potential barrier is further amplified when the combustion engine is removed and battery-electric or fuel-cell hybrid vehicles are considered. This thesis researches the application of model-based design for optimal design of fuel cell hybrid powertrains considering power source degradation. The intent is to develop and evaluate tools that can determine the optimal sizing and control of the powertrain; reducing the amount of over-sizing by numerically optimization rather than a sub-optimal heuristic design. A baseline hybrid fuel cell vehicle model is developed and validated to a hybrid fuel cell SUV designed and built at the University of Waterloo. Lithium-ion battery degradation models are developed and validated to data captured off a hybrid powertrain test stand built as part of this research. A fuel cell degradation model is developed and integrated into the vehicle model. Lifetime performance is modeled for four hybrid control strategies, demonstrating a significant impact of the hybrid control strategy on powertrain degradation. A plug-in variation of the architecture is developed. The capacity degradation of the battery is found to be more significant than the power degradation. Blended and All-electric charge-depleting hybrid control strategies are integrated and lifetime performance is simulated. The blended charge-depleting control strategy demonstrated significantly less degradation than the all-electric strategy. An oversized battery is integrated into the vehicle model and the benefit of oversizing on reducing the battery degradation rate is demonstrated.

Today's automotive industry is undergoing significant changes in technology due to economic, political and environmental pressures. The shift from conventional internal combustion vehicles to hybrid and plug in hybrid electric vehicles brings with it a new host of technical challenges. As the vehicles become more electrified, and the batteries become larger, there are many difficulties facing the battery integration including both embedded control and supervisory control. A very important aspect of Li-Ion battery integration is the state estimation of the battery. State estimation can include multiple states, however the two most important are the state of charge and state of health of the battery. Determining an accurate state of charge estimation of a battery has been an important part of consumer electronics for years now [1]. In small portable electronics, the state of charge of the battery is used to determine the time remaining on the current battery charge. Although difficult, the estimation is simplified by the relatively low charge and discharge currents (approximately + 3C) of the devices and the non-dynamic duty cycle. Hybrid vehicle battery packs can reach much higher charge and discharge currents (+ 20C) [2]. This higher current combined with a very dynamic duty cycle, large changes in temperature, longer periods without usage and long life requirements make state of charge estimation in Hybrid Electric Vehicles (HEV) much more difficult. There have been a host of methods employed by various previous authors. One of the most important factors in state of charge estimation is having an accurate estimation of the actual capacity (depending on state of health) of the battery at any time [3]. Without having an understanding of the state of health of the battery, the state of charge estimation can vary greatly. This paper proposes a state of charge and state of health estimation based on a dual Extended Kalman Filter (EKF). Employing an EKF for the state estimation of the battery pack not only allows for enhanced accuracy of the estimation but allows the control engineer to develop vehicle performance criteria based not only on the state of charge estimation, but also the state of health.

The electrochemical behavior of a poly(2,2,6,6-tetramethylpiperidin- 1-oxyl-4-yl methacrylate) (PTMA) cathode in organic radical batteries with lithium bis(trifluoromethylsulfonyl)imide in N-butyl-N-methyl- pyrrolidinium bis(trifluoromethylsulfonyl)imide (LiTFSI/BMPTFSI) ionic liquid electrolytes is investigated. The ionic liquid electrolytes containing a high concentration of the LiTFSI salt have a high polarity, preventing the dissolution of the polyvinylidene fluoride (PVdF) binder and PTMA in the electrolytes. The results of cyclic voltammetry and AC impedance indicate that an increase in the LiTFSI concentration results in a decrease in the impedance of the lithium electrode, which affects the C-rate performance of batteries. The discharge capacity of the PTMA composite electrode in a 0.6 m LiTFSI/BMPTFSI electrolyte is 92.9 mAh g−1 at 1 C; its C-rate performance exhibits a capacity retention, 100 C/1 C, of 88.3%. Moreover, the battery with the 0.6-m LiTFSI/BMPTFSI electrolyte has very good cycle-life performance.

This paper aims on the study of developing the firmware program for the monitor chips designed inside the battery set of a Notebook power management system, with the function of monitoring safety during battery charge/discharge via the chips; meanwhile, to estimate the residual capacity of the battery. Owing to the chemistry properties of the battery, whose residual capacity will be affected by the current flow during charge/discharge, high/low of the ambient temperature, fatigue of the battery, as a result, variations of the residual capacity will be presented in non-linear. Therefore, in estimation of the battery residual capacity, using the curve learned from the practical experiment on the battery charge/discharge to be the basis for us to find out the appropriate parameters under the relevant influence factors for revision. It will be more accurate in estimation of the battery residual capacity. At the same time, the battery signal can be transmitted to the managing end of the Notebook power management system via the system management interface, which may enable the system to operate more efficiently.