Remaining useful life estimations applied on the sizing and the prognosis of lithium ion battery energy storage systems

The present thesis develops an accurate sizing tool for the most relevant lithium ion battery energy storage system applications considering the aging and the remaining useful life. The developed tool involves firstly, the construction of the aging models of the lithium ion battery health indicators; secondly, the calculation of the end of life based on the evolution of the modelled health indicators; thirdly, the calculation of the levelized cost of the most relevant applications of lithium ion battery energy storage systems; and fourthly, the minimization of the committed error with the constructed aging models supported by electrode level data and prognosis algorithms. The methodology behind the construction and calculation of all the elements integrated on the sizing tool is described throughout the chapters of this thesis. Firstly, the end of life state of the battery is determined as a combined threshold of all the health indicators of interest. Its calculation requires the implementation of an electro-thermal model in a simulation environment defined by the end of life criteria specified by the application requirements. Secondly, the evolution of health indicators of interest are modelled based on the most relevant stress factors. The methodology to acquire the aging data and the construction of the posterior empirical models are presented. The validation of the constructed models based on the acquired data is performed based on three aspects: the accuracy describing the observed cases, the correctness of interpolations and the real life applicability. Thirdly, the simulation environments for lithium ion battery energy storage systems applied on an electric vehicle application and on a stationary application are developed where the levelized cost of different battery solution sizes is calculated. The simulation environment integrates the already developed electric-thermal model, end of life map and aging models. Fourthly, the error done by the constructed aging models is minimized by focusing on the errors done when extrapolating in time and when facing odd events. On one hand, electrode level data is analysed to generate data artificially and reduce the errors when extrapolating in time. On the other hand, a prognosis stochastic algorithm is selected and employed with real life data to deal with the effect that odd events have on the evolution of the health indicators. The validity of many assumptions made for the development of the end of life map, the aging models, the simulation environment used on the sizing tool, the artificial data generator and the real time prognosis tool are proved experimentally

Influence of reaction conditions on hydrothermal carbonization of monosaccharides

The grim perspective of a near future when out-of-control global warming caused by C02 emissions will threaten to put human lives in serious danger is pushing the scientific community to seek for alternatives to fossil fuels to counteract this negative trend. At the moment, fossil fuels are the main source of energy and chemical building blocks for the synthesis of plastics. Hydrothermal carbonization is a process that aims to replace fossil fuels with renewable biomass as source of energy (biofuels) and materials (platform chemicals and hydrothermal carbon). The process of hydrothermal carbonization has been known for a little more than a century as a way to mimic the natural process of coalification of biomass. It consists in a conversion of wet biomass in water, at subcritical temperatures (180-250°C) and autogenous pressure. Biomass is made of lignin, a polymer of alkylphenol derivatives, cellulose and hemicellulose (polysaccharides). These materials, in hydrothermal conditions, undergoes a series of reaction: hydrolysis of large polymer chains, solubilisation of monomers in water, dehydration, fragmentation and ring opening reaction, oxidation and formation of organic acids and re-polymerization to amorphous carbonaceous materials. This process is extremely interesting because some of its products have been recognised as strategic for a future emancipation from fossil fuels: furan derivatives like furfural, 5-hydroxymethylfurfural and levulinic acid can be a source for the synthesis a great variety of chemicals, including biofuels. The amorphous carbonaceous materials (hydrothermal carbon) has been successfully employed as a starting material for the development of electrode in batteries, supercapacitors and fuel cells, or gas capture. However, a thorough understanding of the underlying mechanisms of hydrothermal carbonization still needs to be achieved. The aim of this research project is to evaluate the effect of the chosen parameters on the sugar conversion, the change of the product yields and the morphological and chemical properties of HT carbon; to highlight the correlation between chemicals in the liquid phase and HT carbon; to get a deeper understanding on the chemical structure of HT carbon. The attention was focused on three monosaccharides: fructose, glucose and xylose. Hydrothermal conversion of fructose was tested by varying the reaction time (2-12h), acid catalysis (H2SO4, HNO3, HCl, HBr, HI) and headspace feed gas (air, N2, CO2). The soluble and insoluble products were collected and the results discussed. Fructose proved to be a very reactive substrate for hydrothermal conversion also in plain water and absence of catalyst, leading to a maximum HMF yield of HMF of 52% after 3 h. Strong acids strongly accelerate fructose conversion to carboxylic acids but they have a less pronounced effect on HT carbon formation. A pressurized system has also a positive effect in terms of conversion. Morphological and chemical analysis of HT carbon produced showed that the alkylfuran skeleton evolves through time to a more condensed and cross-linked structure. The presence of a family of oligomers formed by units with a mass of 211 Da suggests that HT formation proceeds via progressive polymerization of a well-defined monomer. Hydrothermal conversion of glucose was performed in conditions of increasing reaction time (2-12h) and different acid catalysis (H2SO4, HNO3, HCl, HBr, HI). In this case, glucose proved to be a less sensitive substrate to dehydration than fructose. Acid catalysis greatly increase its conversion and it is possible to distinguish the different contribution of the anions in the ability to catalyse the reaction. Morphological and chemical analysis of HT carbon produced showed similar results to those obtained from fructose but also suggest that HMF concentration throughout time plays a key role in the growth rate of carbon particles. Oligomers species were also detected in this case. Finally, the effect of reaction time (2-12h) was evaluated for the hydrothermal conversion of xylose. The structural difference between xylose and the previously studied fructose and glucose has a profound impact on its reactivity in hydrothermal conditions. Although the time scale of its conversion to FF is roughly comparable to glucose conversion to HMF, FF is notably more stable than its hexose-derived furan analogous. Its relative stability depends on the fact that there is no reaction occurring on FF that is similar to the HMF ring opening. Lower HT carbon yields also suggest that carbon formation is less efficient with FF molecules. The slight difference of the FF molecule has repercussions on the structure of carbon spheres as well as their chemical structure. HT carbon particles have a reduced tendency to aggregate as reaction time proceeds. Chemical characterization showed similarities with C6 HT carbon but also a distinctive more aromatic character that once again can be ascribed once the different chemistry of FF. In this case, a few species in the mass range between 800 Da and 1500 Da were found, whose masses increase with time, with little evidence of oligomeric nature. The kinetic modelling of the data of concentration versus reaction time allowed to find the reaction rate constants associated with glucose, fructose and xylose degradation to their dehydration products (HMF and furfural respectively) as well as the constants related to levulinic acid and hydrothermal carbon formation. These constants are in good agreement with previous studies and proves that glucose dehydration is the slowest (k=1.8 ∙10-5 s-1), followed by xylose (k=3.9 ∙10-5 s-1) and fructose (k=7.6 ∙10-5 s-1)

Towards a circular economy: fabrication and characterization of biodegradable plates from sugarcane waste

Bagasse pulp is a promising material to produce biodegradable plates. Bagasse is the fibrous residue that remains after sugarcane stalks are crushed to extract their juice. It is a renewable resource and is widely available in many countries, making it an attractive alternative to traditional plastic plates. Recent research has shown that biodegradable plates made from Bagasse pulp have several advantages over traditional plastic plates. For example, they are more environmentally friendly because they are made from renewable resources and can be composted after use. Additionally, they are safer for human health because they do not contain harmful chemicals that can leach into food. The production process for Bagasse pulp plates is also relatively simple and cost-effective. Bagasse is first collected and then processed to remove impurities and extract the pulp. The pulp is then molded into the desired shape and dried to form a sturdy plate. Overall, biodegradable plates made from Bagasse pulp are a promising alternative to traditional plastic plates. They are environmentally friendly, safe for human health, and cost-effective to produce. As such, they have the potential to play an important role in reducing plastic waste and promoting sustainable practices. Over the years, the world was not paying strict attention to the impact of rapid growth in plastic use. As a result, uncontrollable volumes of plastic garbage have been released into the environment. Half of all plastic garbage generated worldwide is made up of packaging materials. The purpose of this article is to offer an alternative by creating bioplastic goods that can be produced in various shapes and sizes across various sectors, including food packaging, single-use tableware, and crafts. Products made from bagasse help address the issue of plastic pollution. To find the optimum option for creating bagasse-based biodegradable dinnerware in Egypt and throughout the world, researchers tested various scenarios. The findings show that bagasse pulp may replace plastics in biodegradable packaging. As a result of this value-added utilization of natural fibers, less waste and less of it ends up in landfills. The practical significance of this study is to help advance low-carbon economic solutions and to produce secure bioplastic materials that can replace Styrofoam in tableware and food packaging production