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
Impact of micro-cycles on the lifetime of lithium-ion batteries: an experimental study
(Elsevier, 2022) Soto Cabria, Adrián; Berrueta Irigoyen, Alberto; Mateos Inza, Miren; 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 Gobierno de Navarra / Nafarroako Gobernua
Experimental aging studies are commonly conducted on lithium-ion batteries by full charge and discharge cycles. However, such profiles may differ from the actual operation of batteries in electric vehicles and stationary applications, where they are subjected to different partial charges and discharges. These partial cycles, which take place during a main charge or discharge process, are called micro-cycles if their depth of discharge is <2 %. A number of authors have pointed out the relevance of the time resolution to estimate the energy throughput of a battery due to these micro-cycles in applications such as renewable microgrids. However, to the best of our knowledge, there are no experimental studies in the literature that assess the impact of these micro-cycles on battery degradation. In this article, the impact of micro-cycles on the loss of performance of a lithium-ion battery is experimentally studied. The results show that micro-cycles have a negligible, or even positive effect on the aging of lithium-ion cells compared to the aging caused by full cycles. In fact, if charge throughput or equivalent full cycles are used to measure the use of a battery, then cells subjected to micro-cycles exhibit a 50 % extended lifetime compared to cells only subjected to full cycles. More precisely, cells including micro-cycles with depth of discharge of 0.5 % lasted for nearly 3000 equivalent full cycles, whereas cells aged under standard deep cycles lasted for no >1500. Nevertheless, if the number of deep cycles, disregarding micro-cycles, is the unit to measure battery use, then the degradation of cells with and without micro-cycles is similar. Based on this result, the number of cycles can be identified as a more accurate variable to measure the use of a cell, in comparison to charge throughput.
Open Access
Influence of renewable power fluctuations on the lifetime prediction of lithium-ion batteries in a microgrid environment
(IEEE, 2019) Soto Cabria, Adrián; 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; Gobierno de Navarra / Nafarroako Gobernua
This contribution analyses lifetime estimation errors due to the effect of power fluctuations in lithium-ion batteries connected to microgrids when different time steps are used for the calculations. Usually, not every second data are available or the computational cost is excessively high. Those facts result in the use of larger time steps. However, the increase of the time steps may turn out in too optimistic predictions. Data from a real microgrid make it possible to optimize calculation times while keeping low errors. The results show that when 1 minute time step is set, the computation time is reduced by 14.4 times while the lifetime overstatement is only 3.5-5.2% higher, depending on the aging model.
Open Access
Role of student associations in the acquisition of competences in university engineering programs
(IEEE, 2023) Samanes Pascual, Javier; Parra Laita, Íñigo de la; Berrueta Irigoyen, Alberto; Rosado Galparsoro, Leyre; Soto Cabria, Adrián; Elizondo Martínez, David; Catalán Ros, Leyre; Sanchis Gúrpide, Pablo; Institute of Smart Cities - ISC
Students in the STEM field (Science, Technology, Engineering and Mathematics), do not only require deep technical knowledge, but a complete set of global skills related to management, teamwork, lifelong learning, personal development, communications skills or proactiveness, abilities often referred as soft-skills. Student-led organizations, and specifically, university student associations, are one of the best alternatives to promote the acquisition of soft-skills in STEM high education fields. These skills are competences already included in official university programs that can hardly be addressed or acquired from traditional university education. This article studies how student enrollment in student led organizations (SLOs), with an active participation on their organization and activities, allows engineering students to achieve a better development of these soft skills. As case study, a medium size university, with 9000-students and eleven SLOs, six of them focused on STEM related fields, is used in this paper. A survey is conducted among the university community to identify their degree of participation in SLOs, and to test whether participation in these initiatives increases students' self-perception of their soft skill acquisition during their university studies. This survey shows how students of engineering programs, with a high degree of involvement in SLOs, demonstrated greater confidence in their soft skills at the end of their university years.
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
Optimizador metaheurístico para la gestión y dimensionado de baterías Li-ion para aplicaciones renovables
(2018) Soto Cabria, Adrián; Ursúa Rubio, Alfredo; Berrueta Irigoyen, Alberto; Escuela Técnica Superior de Ingenieros Industriales y de Telecomunicación; Telekomunikazio eta Industria Ingeniarien Goi Mailako Eskola Teknikoa
Debido al aumento de potencia en el sistema eléctrico pueden aparecer nuevos problemas de en la red debido principalmente al carácter impredecible de los recursos renovables (principalmente sol y viento). Entre ellos se encuentran los asociados a las sobrecargas cuando la generación es mayor que la demanda. Este proyecto trata de contribuir en la integración de las energías renovables en el mix energético. Para ello se desarrolla un optimizador que engloba la gestión de una batería Li-ion así como el cálculo del tamaño óptimo.
Open Access
Impact of micro-cycles on the lifetime of lithium-ion batteries - EIS analysis
(IEEE, 2024-07-30) Nováková, Katerina; Berrueta Irigoyen, Alberto; Soto Cabria, Adrián; 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
Experimental studies of lithium-ion batteries are very often based only on deep charge and discharge cycles. However, these test profiles do not fully reflect the actual operation of the battery in an electric vehicle or in stationary applications, where the battery is not only loaded during the main charging and discharging profiles, but it is also stressed by the current throughput caused by renewable power fluctuations or by auxiliary services. These cycles, which are superimposed to the main charge and discharge processes and have a depth of discharge not exceeding 2%, are called micro-cycles. Although there are several simulation studies that attempt to capture this issue, there is still no comprehensive experimental study that has the phenomena that occur during micro-cycling. This paper presents an experimental analysis of micro-cycles, providing a detailed view of the different processes taking place in the battery during aging, by means of a detailed analysis of the results from electrochemical impedance spectroscopy (EIS). By studying the single electrochemical processes in detail, this paper explains the benefits of micro-cycling in terms of extending the lifetime of the battery.
Open Access
Critical comparison of energy management algorithms for lithium-ion batteries in renewable power plants
(IEEE, 2019) Berrueta Irigoyen, Alberto; Soto Cabria, Adrián; García Solano, Miguel; 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
Lithium-ion batteries are gaining importance for a variety of applications due to their price decrease and characteristics improvement. A good energy management strategy is required in order to increase the profitability of an energy system using a Li-ion battery for storage. The vast number of management algorithms that has been proposed to optimize the achieved profit, with diverse computational power requirements and using models with different complexity, raise doubts about the suitability of an algorithm and the required computation power for a particular application. The performance of three energy management algorithms based on linear, quadratic, and dynamic programming are compared in this work. A realistic scenario of a medium-sized PV plant with a constraint of peak shaving is used for this comparison. The results achieved by the three algorithms are compared and the grounds of the differences are analyzed. Among the three compared algorithms, the quadratic one seems to be the most suitable for renewableenergy applications, given the undue simplification of the battery aging required by the linear algorithm and the discretization and computational power required by a dynamic algorithm.
Open Access
Integration of second-life battery packs for self-consumption applications: analysis of a real experience
(IEEE, 2021) Soto Cabria, Adrián; Berrueta Irigoyen, Alberto; Zorrilla, Pablo; Iribarren Zabalegui, Álvaro; Castillo, Diego H.; Rodríguez Rodríguez, Wenceslao Eduardo; Rodríguez, Adolfo J.; Vargas Requena, Dávid Tomás; Matías Maestro, Ignacio; Sanchis Gúrpide, Pablo; Ursúa Rubio, Alfredo; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren; Institute of Smart Cities - ISC; Ingeniería Eléctrica, Electrónica y de Comunicación; Gobierno de Navarra / Nafarroako Gobernua, 0011–1411–2018–000029 GERA; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa, ReBMS PJUPNA1904
This contribution presents a methodology for the integration of Li-ion batteries discarded from electric vehicle into a collective self-consumption installation, showing the technical feasibility of such battery second use. In this regard, the state of charge (SOC) estimation is a relevant issue for the energy management of the second-life battery. Therefore, a SOC estimator is proposed in this contribution and tested in field. Moreover, the revealed costs analysis allows an economic comparison between the integration of a discarded battery pack in a second-life application or a remanufacture of these packs, thereby selecting the most suitable cells to build second-life batteries. This is a crucial issue for companies focused on the development of second-life batteries. The results obtained after testing the second-life battery pack in a real installation make it possible to extol the benefits of including this type of batteries in a self-consumption system, reaching a self-consumption ratio of 69 % and reducing by 36 % the maximum power peak demanded from the grid.
Open Access
Non-invasive aging analysis of lithium-ion batteries in extreme cold temperatures
(IEEE, 2021) Soto Cabria, Adrián; Berrueta Irigoyen, Alberto; Oficialdegui, Ignacio; 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
This paper presents a non-invasive technical analysis of the degra-dation of four lithium-ion batteries (LIBs) used in extreme frigid weather. In contrast to other studies in which the batteries were tested in laboratory conditions, the LIBs studied in this paper were aged in a real application, more specifically in the WindSled project. In this project, an expedition was made using a zero-emission vehicle drawn by kites, covering more than 2500 kilometers on the East Antarctic Plateau. The study performed in this paper aims to quantify the degradation of the LIBs during the expedition. The results show a 5 % capacity fade, a 30 % increase in the internal resistance and no substantial increase in the impedance of the solid electrolyte interface (SEI). Moreover, no evidence of dendrite growth at the anode is inferred by the interpretation of the distri-bution of relaxation times (DRT), incremental capacity analysis (ICA) and differential voltage analysis (DV). Based on these re-sults, it can be claimed that the LIBs used in the WindSled Project can successfully operate under 50 C. Furthermore, since non-invasive techniques were used to characterize the batteries, they can still be used in upcoming expeditions, with subsequent financial and environmental benefits.