• Energy Research

Obtaining precise reducer order battery models is a key component in designing lithium-ion battery management systems. In general, with conventional order reduction techniques, low order is followed by low accuracy. To overcome such limitation, this paper presents a frequency-based constructive method to obtain broad-band low-order approximations of the solid-phase lithium-ion diffusion submodel, the core of the reference pseudo-two-dimensional electrochemical model of lithium-ion cells. The proposed method is a combination of an improvement on the residue grouping technique and of standard balancing and truncation/residualization methods borrowed from control systems theory. As main result, dramatic order reductions from 3000th to 5th-order with minimum accuracy losses are obtained. Taking a well-known case-study of a lithium-ion battery model, it is shown that 5th-order models offer approximations with maximum absolute errors of 0.5%, for characteristic times up to $$9.54\times 10^4~\text {s}$$ . The proposed method will help to obtain accurate real-time estimations of surface concentration and state of charge of lithium-ion batteries.

One of the biggest challenges of our time is climate change. Every day, at different places of the world, the planet sends alarming messages about the enormous transformations it is experiencing due to human-based activities. The latter are responsible for changing weather patterns that threaten food production, energy production and energy consumption, the desertification of land, the displacement of people and animals because of food and water shortages due to the reductions in rainfall, natural disasters and rising sea levels. The effects of climate change affect us all, and if drastic measures are not considered in a timely manner, it will be more difficult and costly to adapt to the aforementioned effects in the future. Considering this context, the aim of this work is to implement a prospective study/structural analysis to the identified sectors of a regional plan of adaptation to climate change so as to promote the resilience of the region against the negative phenomena generated by the climate crisis. This was achieved in two steps: first, we identified the relationships between the strategic sectors of the plan and organized them in order of importance. Second, we assessed the effectiveness of several public policies oriented towards a city’s resilience according to their impact upon the strategic sectors of the plan and the co-benefits generated by their implementation for society. The results highlight that the most essential sectors for the mitigation of climate change are flood risk management, built environment, forest ecosystem management, human health, tourism and rise in sea level. As a consequence, the most important measures for the resilience of the North Aegean Region against climate change are the ones related to the preparation of strategic master plans for flood protection projects.

Electrochemical models are a widespread framework to simulate lithium-ion (Li-ion) batteries and to design their battery management algorithms. To obtain numerically efficient models, the polynomial approximation (PA) is one of many order reduction techniques applied to the solid-state lithium-ion (SSLi+) diffusion equation, the core of the so-called pseudo-two-dimensional electrochemical model (P2DM). Although the validity of PA is constrained to slow-varying current scenarios, many algorithms reported in the literature to estimate the state-of-charge of Li-ion cells rely on low-order PA-based dynamic models (PADMs) derived from the P2DM. Moreover, assuming that most properties of their low-order counterparts are inherited, some authors suggest that PADMs of arbitrary high order can be used to provide very accurate approximations of the state-of-charge, even under complex operating conditions. Nevertheless, to authors knowledge, in the open literature there is not a proper analysis to support such assertion. In this paper, by introducing a systematic method to derive PADMs of arbitrary order, the ability of high-order PADMs to reproduce the average and surface concentrations described by the SSLi+ diffusion equation is investigated in time and frequency domains, with the aid of classic control systems theory techniques. The main result shows that PADMs of order greater than 2 are structurally fragile as non-minimum-phase zeros as well as spurious unstable modes are induced by the PA technique, implying that high-order PADMs are not suitable for simulation or estimation purposes because of their weak internal structure.

Abstract The single-particle model is a useful mathematical representation for state-of-charge observation, parameter identification and control of lithium-ion batteries. This model is a simplified electrochemical formulation where ionic intercalation, described as a diffusive process, is considered as the dominant dynamics. In the search for a more efficient numerical solution of the involved partial differential equations, many approximations have been reported. However, most of them are valid just under restricted operating conditions. In this paper, spatial semidiscretization is reintroduced as the precision of approximations could be arbitrarily chosen with this approach. Three discretization methods are applied in a classical fashion, evaluated and compared in both time and frequency domains: finite difference, finite element and differential quadrature. In addition, two commonly used low order approximations are tested against semidiscretization approximations. The best results are obtained with the differential quadrature method in its polynomial version. Two model truncation criteria are also explored, one is based on bandwidth selection and the other on residue analysis, where the first resulted to be more conservative. Finally, simulations of representative reduced order approximations of the single-particle model are compared against experimental data found in the literature.

Transportation systems help in shaping an area’s economic health and quality of life, providing the infrastructure for the mobility of people and goods. Nevertheless, the negative externalities of car-oriented urban-metropolitan planning have heightened awareness for the need of urban planning approaches that incorporate sustainable mobility. Consequently, cities worldwide have increasingly produced sustainable mobility plans. This points to the need of creating mechanisms to implement these sustainable plans, particularly in large, complex, and fast-growing cities. This paper provides guidelines to facilitate the implementation of Sustainable Mobility Plans by focusing on the case of Mexico City. This is achieved by applying the complex large-scale integrated open systems (CLIOS) systemic analysis, in two steps: first, we facilitate the identification of the complexities and relationships among the essential systems of Mexico City’s urban structure, along with the recognition of their most important components and the institutions involved within the urban planning process. Second, we assess the effectiveness of the public policies–strategies that form part of Mexico City’s Sustainable Mobility Plan and organize them in order of importance. The results show which principal subsystems should be considered for sustainable mobility and which public policies–strategies should be prioritized in order to implement the aforementioned plan effectively.

Transport systems are capable of contributing to the economic robustness of a geographic area and the well-being of its inhabitants via the supply of the necessary assets for the mobility of people and goods. However, transport projects have the capacity to produce several negative externalities such as water pollution, air pollution, barrier effects, noise, and ecological impact, which affect the quality of people’s life. Considering these facts, the main purpose of this study is to indicate methodologically how the negative externalities of transport are interlinked, so that to promote sustainable mobility development. This paper reveals via the method of structural analysis, the interrelations between the negative externalities of transport, firstly to organize them hierarchically and secondly to evaluate the potential of sustainable mobility strategies concerning the co-benefits generated by their implementation for society. The results show that the negative externalities of transport are not isolated phenomena; on the contrary, they are interlinked and can be organised hierarchically according to the relationships between them so that certain public policies can be prioritized and the negative impacts of transport can be tackled more effectively. The most critical negative externalities are the invasion of public space for the construction of more roads, along with road accidents, congestion, and local air pollution. On the other hand, the most important group of strategies for sustainable mobility are the ones oriented to urban design, and more specifically to transit-oriented development.

The mechanical torque of a wind turbine is modeled from a friction phenomenon perspective. Two models for the torque generated are proposed based on a relative speed between the wind and turbine blades. The main advantage of these models is the possibility of using real-time standard identification techniques for recovering their parameters value. Models are compared with a heuristic reference model showing good performance.