Open Access
Analytical modeling of high-frequency winding loss in round-wire toroidal inductors
(IEEE, 2020) Elizondo Martínez, David; Barrios Rípodas, Ernesto; Sanchis Gúrpide, Pablo; Ursúa Rubio, Alfredo; Ingeniería Eléctrica, Electrónica y de Comunicación; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren
Toroidal inductors are present in many different industrial applications, thus, still receive researchers' attention. AC winding loss in these inductors have become a major issue in the design process, since switching frequency is being continuously increased in power electronic converters. Finite element analysis software or analytical models such as Dowell's are the main existing alternatives for their calculation. However, the first one employs too much time if different designs are to be evaluated and the second one lacks accuracy when applied to toroidal inductor windings. Looking for an alternative that overcomes these drawbacks, this paper proposes an accurate, easy-to-use analytical model, specifically formulated for calculating high-frequency winding loss in round-wire toroidal inductors.
Open Access
Identification of critical parameters for the design of energy management algorithms for Li-ion batteries operating in PV power plants
(IEEE, 2020) Berrueta Irigoyen, Alberto; Soto Cabria, Adrián; Marcos Álvarez, Javier; Parra Laita, Íñigo de la; Sanchis Gúrpide, Pablo; Ursúa Rubio, Alfredo; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren; Institute of Smart Cities - ISC; Ingeniería Eléctrica, Electrónica y de Comunicación; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa, ReBMS PJUPNA1904; Gobierno de Navarra / Nafarroako Gobernua, 0011-1411-2018-000029 GERA
Lithium-ion batteries are gaining importance for a variety of applications due to their price decrease and characteristics improvement. For a proper use of such storage systems, an energy management algorithm (EMA) is required. A number of EMAs, with various characteristics, have been published recently, given the diverse nature of battery problems. The EMA of deterministic battery problems is usually based on an optimization algorithm. The selection of such an algorithm depends on a few problem characteristics, which need to be identified and closely analyzed. The aim of this article is to identify the critical optimization problem parameters that determine the most suitable EMA for a Li-ion battery. With this purpose, the starting point is a detailed model of a Li-ion battery. Three EMAs based on the algorithms used to face deterministic problems, namely dynamic, linear, and quadratic programming, are designed to optimize the energy dispatch of such a battery. Using real irradiation and power price data, the results of these EMAs are compared for various case studies. Given that none of the EMAs achieves the best results for all analyzed cases, the problem parameters that determine the most suitable algorithm are identified to be four, i.e., desired computation intensity, characteristics of the battery aging model, battery energy and power capabilities, and the number of optimization variables, which are determined by the number of energy storage systems, the length of the optimization problem, and the desired time step.
Open Access
Integrated lithium-ion battery model and experimental validation of a second-life prototype
(IEEE, 2023-08-31) Pérez Ibarrola, Ane; San Martín Biurrun, Idoia; Sanchis Gúrpide, Pablo; Ursúa Rubio, Alfredo; Ingeniería Eléctrica, Electrónica y de Comunicación; Ingeniaritza Elektrikoa, Elektronikoa eta Telekomunikazio Ingeniaritza; Institute of Smart Cities - ISC; Gobierno de Navarra / Nafarroako Gobernua
A battery model predicts the battery performance, which can be a useful tool for optimizing battery design and preventing unsafe operation. This becomes especially significant in second-life batteries where the cells have already endured degradation and predicting the lifetime becomes challenging. The assessment of physical phenomena is often performed individually, but the overall battery behavior depends on their interaction. For this purpose, an integrated battery model is developed. Equivalent electric circuits are interconnected to represent the electrochemical reactions, thermodynamic phenomena, and heat transfer mechanisms of the battery. To consider cell degradation, calendar and cycling aging were represented using a semi-empirical model. A battery management system is included to oversee and remain within the safe limits of battery voltage, temperature, and current. Additionally, a passive cell balancing distributes charge evenly. The integrated model is applied to a second-life battery prototype with a nominal capacity and power of 45 Ah and 4 kW, respectively. Its performance is validated with constant current and power cycles, as well as in a microgrid with photovoltaic generation under a self-consumption profile. The model accurately reproduces experimental results of battery power, voltage, temperature, and state of charge.
Open Access
Temperature indicators and overtemperature detection in lithium-ion batteries based on electrochemical impedance spectroscopy
(IEEE, 2023) Lalinde Sainz, Iñaki; Berrueta Irigoyen, Alberto; Soto Cabria, Adrián; Arza, Joseba; Sanchis Gúrpide, Pablo; Ursúa Rubio, Alfredo; Ingeniería Eléctrica, Electrónica y de Comunicación; Institute of Smart Cities - ISC; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren
Lithium-ion batteries are the leading technology for energy storage systems due to their attractive advantages. However, the safety of lithium-ion batteries is a major concern, as their operating conditions are limited in terms of temperature, voltage and state of charge. Therefore, it is important to monitor the conditions of lithium-ion batteries to guarantee safe operation. To this end, in the present work, we analyze electrochemical impedance spectroscopy (EIS) as a tool to estimate the temperature of batteries. Overtemperature abuse tests from 25 °C to 140 °C are performed at various states of charge, and EIS measurements are obtained during the tests. The influence of temperature on cell impedance at different frequencies is analyzed and new findings are revealed. The real part of the impedance is identified to be the best indicator for cell temperature estimation by EIS. In addition, the best frequency to achieve accurate temperature monitoring, avoiding disturbances produced by state of charge variations, is proposed based on experimental results. Finally, EIS is proven to be a reliable technique for overtemperature and thermal runaway detection.
Open Access
Winding resistance measurement in power inductors - understanding the impact of the winding mutual resistance
(IEEE, 2021) Barrios Rípodas, Ernesto; Elizondo Martínez, David; Ursúa Rubio, Alfredo; Sanchis Gúrpide, Pablo; Ingeniería Eléctrica, Electrónica y de Comunicación; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren
Inductors are cornerstone components in power electronics converters. Since winding loss is the dominant loss mechanism in these components, its accurate measurement is fundamental for the validation of the inductor's operation and design. The techniques for the winding resistance R_{w} measurement in power inductors can be classified into two groups, indirect and direct. Both techniques use coupled inductors to separate winding and core power losses. If coupled inductors with non-zero winding mutual resistances R_{w,m} are used, invalid results are obtained with these techniques. Understanding the meaning of R_{w,m} in coupled inductors is complex. In this paper, the impact of R_{w,m} on the inductor R_{w} measurement techniques is demonstrated and practical guidelines for the design of the zero R_{w,m} coupled inductors are given. Particularly, the location of the auxiliary winding for the direct technique is investigated. In order to compare the R_{w} measurement techniques and to validate the coupled inductor's R_{w,m} impact, two different inductors are built and tested. The results are compared with the values for R_{w} calculated by FEA simulation. It is found that only the direct technique with an auxiliary winding carefully designed and located following the guidelines given in this paper makes the accurate measurement of R_{w} in power inductors possible.
Open Access
Methodology for comparative assessment of battery technologies: experimental design, modeling, performance indicators and validation with four technologies
(Elsevier, 2025-01-15) Irujo Izcue, Elisa; Berrueta Irigoyen, Alberto; Sanchis Gúrpide, Pablo; Ursúa Rubio, Alfredo; Ingeniería Eléctrica, Electrónica y de Comunicación; Ingeniaritza Elektrikoa, Elektronikoa eta Telekomunikazio Ingeniaritza; Institute of Smart Cities - ISC; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa, PJUPNA2023-11380; Gobierno de Navarra / Nafarroako Gobernua
An increasing number of applications with diverse requirements incorporate various battery technologies. Selecting the most suitable battery technology becomes a tedious task as several aspects need to be taken into account. Two of the key aspects are the battery characteristics under temperature variations and their degradation. While numerous contributions using tailored assessment methods to evaluate both aspects for a particular application exist in the literature, a general methodology for analysis is necessary to enable a quantitative comparison between different technologies. We propose in this paper a novel methodology, based on performance indicators, to quantify the potential and limitations of a battery technology for diverse applications sharing a similar operational profile. A quantification of phenomena such as the influence of high and low temperatures on the battery, or the effect of cycling and state of charge on battery aging is obtained. In pursuit of these indicators, an experimental procedure and the fitting of aging model parameters that allow their calculation are proposed. As an additional outcome of this work, a general aging model that allows comprehensive analysis of aging behavior is developed and the trade-off between experimental time and accuracy is analyzed to find an optimal experimental time between 2 and 4 months, depending on the studied battery technology. Finally, the proposed methodology is applied to four battery technologies in order to show its potential in a real case-study.
Open Access
New design alternatives for a hybrid photovoltaic and doubly-fed induction wind plant to augment grid penetration of renewable energy
(IEEE, 2021) Goñi, Naiara; Sacristán Sillero, Javier; Berrueta Irigoyen, Alberto; Rodríguez Rabadan, José Luis; Ursúa Rubio, Alfredo; Sanchis Gúrpide, Pablo; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren; Institute of Smart Cities - ISC; Ingeniería Eléctrica, Electrónica y de Comunicación; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa
Reducing carbon emissions is essential to stop climate change. The grid-share of renewable generation plants is increasing, being wind and photovoltaic plants the most common ones, whereas conventional plants are the only ones that provide the necessary services to maintain the grid stability and keep the generation-demand balance. However, with the aim of achieving carbon-neutral generation, conventional plants are being dismantled. This leads to the imminent need of providing these services with renewable plants. Due to this challenge, this proposal analyses a hybrid plant composed by wind and photovoltaic generation with two types of storage, lithium-ion batteries and a thermal storage system based on volcanic stones. In order to compare both strategies, a technoeconomic methodology is explained that allows to optimally size the plant, using the current prices of each technology. The most cost-competitive proposal turns to be the hybrid plant with thermal storage, composed by 623.9 MW installed power and 21.9 GWh of storage, which could replace a 100 MW, 24/7 conventional power plant, with an LCOHS (levelized cost of hybrid system) of 118.38 €/MWh, providing identical grid services and an equivalent inertia in a way committed with the environment. This is in turn a zero-carbon emissions solution perfectly matched to a second life plan for a conventional power plant.
Open Access
Health indicator selection for state of health estimation of second-life lithium-ion batteries under extended ageing
(Elsevier, 2022) Braco Sola, Elisa; San Martín Biurrun, Idoia; Sanchis Gúrpide, Pablo; Ursúa Rubio, Alfredo; Stroe, Daniel-Ioan; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren; Institute of Smart Cities - ISC; Ingeniería Eléctrica, Electrónica y de Comunicación; Gobierno de Navarra / Nafarroako Gobernua; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa
Nowadays, the economic viability of second-life (SL) Li-ion batteries from electric vehicles is still uncertain. Degradation assessment optimization is key to reduce costs in SL market not only at the repurposing stage, but also during SL lifetime. As an indicator of the ageing condition of the batteries, state of health (SOH) is currently a major research topic, and its estimation has emerged as an alternative to traditional characterization tests. In an initial stage, all SOH estimation methods require the extraction of health indicators (HIs), which influence algorithm complexity and on-board implementation. Nevertheless, a literature gap has been identified in the assessment of HIs for reused Li-ion batteries. This contribution targets this issue by analysing 58 HIs obtained from incremental capacity analysis, partial charging, constant current and constant voltage stage, and internal resistance. Six Nissan Leaf SL modules were aged under extended cycling testing, covering a SOH range from 71.2 % to 24.4 %. Results show that the best HI at the repurposing stage was obtained through incremental capacity analysis, with 0.2 % of RMSE. During all SL use, partial charge is found to be the best method, with less than 2.0 % of RMSE. SOH is also estimated using the best HI and different algorithms. Linear regression is found to overcome more complex options with similar estimation accuracy and significantly lower computation times. Hence, the importance of analysing and selecting a good SL HI is highlighted, given that this made it possible to obtain accurate SOH estimation results with a simple algorithm.
Open Access
Onset of irreversible reactions in overcharging lithium-ion cells: an experimental and modeling approach
(IEEE, 2023) Irujo Izcue, Elisa; Berrueta Irigoyen, Alberto; Lalinde Sainz, Iñaki; Arza, Joseba; Sanchis Gúrpide, Pablo; Ursúa Rubio, Alfredo; Ingeniería Eléctrica, Electrónica y de Comunicación; Institute of Smart Cities - ISC; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren
Lithium-ion batteries are energy storage systems used in an increasing number of applications. Due to their flammable materials, their use entails risks of fire and explosion. The study of the abuse operation of these batteries before reaching the thermal runaway is a relevant research topic to prevent safety issues. There are various studies in the bibliography providing exhaustive thermal studies of the safe operating area, as well as concerning the thermal runaway. However, the onset irreversible reactions, that take place at a SOC around 110%, have not been properly analyzed. We present in this contribution an experimental study of this onset reaction measured in pouch Li-ion cells under various conditions of charge current and temperature. We also propose a lumped-parameter thermal model for the cell, which allows a detailed characterization of this exothermic reaction. The results achieved in this contributions can be a key tool to prevent overcharge accidents that may arise due to malfunctioning of the battery charger or battery management system.
Open Access
Applied method to model the thermal runaway of lithium-ion batteries
(IEEE, 2021) Lalinde Sainz, Iñaki; Berrueta Irigoyen, Alberto; Sanchis Gúrpide, Pablo; Ursúa Rubio, Alfredo; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren; Institute of Smart Cities - ISC; Ingeniería Eléctrica, Electrónica y de Comunicación; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa
The thermal runaway (TR) is one of the most dangerous phenomena related to lithium-ion batteries. For this reason, there are different proposals in the literature for its modelling. Most of these proposed models take into account the decomposition reactions between the internal components of the cell, and base the adjustment of the parameters on numerous abuse tests that lead to the appearance of TR. However, these tests are destructive, require specific equipment, present a high economic cost and are very time consuming. This paper proposes a modelling method which enables the development of TR models with the use of fewer resources. This method is based on chemical kinetics, which allow a simplification of the general modelling process published in the literature. At the same time it maintains good accuracy and makes it possible to define the TR behavior of any type of cell, regardless of its chemistry, shape or size. Furthermore, the proposed method allows the use of the experimental results most commonly presented in the specialized literature, which significantly reduces the need for destructive testing. The presented modelling method achieves a good compromise between accuracy and applicability in the validations shown in the paper.