Open Access
Incremental capacity analysis of lithium-ion second-life batteries from electric vehicles under cycling ageing
(IEEE, 2021) Braco Sola, Elisa; San Martín Biurrun, Idoia; 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
Nowadays, the reuse of batteries from electric vehicles is considered a promising solution to benefit from their remaining energy and extend their lifespan. Yet, the economic viability of these second-life batteries is still uncertain, and the optimization of testing at their reconfiguration stage and during their lifetime is the key to ensure their success. This paper aims to assess Incremental Capacity Analysis technique in Nissan Leaf modules during their second-life use, in order to evaluate both its potential as an State of Health estimator and as a tool to identify underlying degradation mechanisms. Despite the different internal state and ageing rates observed between the tested modules, ICA is found to be consistent at similar SOH levels. The influence of ageing, current and temperature on ICA is evaluated through an accelerated cycling test. Results show that ICA is a promising alternative to estimate SOH during second life even at currents up to C/2 and testing temperatures of 45 °C. However, testing by accelerated currents and temperatures is not recommended for the identification of degradation mechanisms.
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
Analysis and modelling of calendar ageing in second-life lithium-ion batteries from electric vehicles
(IEEE, 2022) Braco Sola, Elisa; San Martín Biurrun, Idoia; Sanchis Gúrpide, Pablo; Ursúa Rubio, Alfredo; Ingeniería Eléctrica, Electrónica y de Comunicación; Institute of Smart Cities - ISC; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren; Gobierno de NAVARRA / Nafarroako Gobernua
The reuse of Li-ion batteries from electric vehicles is a promising alternative to recycling nowadays. However, the technical and economic viability of these second-life (SL) batteries is not yet clear. Degradation assessment plays a key role not only to analyse the impact of ageing factors in reused batteries, but also to quantify their durability. In this context, this contribution aims to analyse calendar ageing behaviour in SL cells. 16 reused Nissan Leaf modules are aged during 750 days under three temperatures and four State of Charge (SOC), covering a State of Health range from 72.2 % to 13 %. The impact of temperature and SOC as stress factors is firstly analysed, concluding that their increase accelerates ageing. Temperature rise is found to have a major impact, accelerating up to 27 times capacity fade and almost 6 times resistance increase when compared to light ageing conditions, while increasing SOC nearly doubles ageing rates. The worst ageing case is found to be the combination of 60 ◦C and 66 % of SOC. Regarding degradation trends, they are proven to be constant during all SL lifetime. This work also proposes and validates a calendar ageing model for SL cells. Accuracy of validation results show a fitting Rsq of 0.9941 in capacity fade and 0.9557 in resistance increase, thereby tracking the heterogeneous degradation of the SL cells under calendar ageing.
Open Access
Lithium-ion second-life batteries: aging modeling and experimental validation
(IEEE, 2024-08-30) 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; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa, PJUPNA2023-11380; Gobierno de Navarra / Nafarroako Gobernua
Re-utilizing lithium-ion batteries from electric vehicles reduces their environmental impact. To ensure their optimal sizing and safe use, identifying the current state of the battery and predicting its remaining useful life is essential. This work analyzes the degradation mechanisms involved and proposes an aging model that utilizes a semi-empirical approach to accurately reproduce the battery's state of health within a range of 75-45 %. Calendar aging includes dependencies on temperature and state of charge while cycling aging is modeled based on depth of discharge, medium SOC, temperature, and Crate. The model is validated against experimental data from 14 LMO/LNO cells previously used in actual Nissan Leaf vehicles and an RMSE bellow 2.5 % is achieved in every case.
Open Access
Initiative to increment the number of women in STEM degrees: women, science and technology chair of the Public University of Navarre
(IEEE, 2020) Aranguren Garacochea, Patricia; San Martín Biurrun, Idoia; Catalán Ros, Leyre; Martínez Ramírez, Alicia; Jurío Munárriz, Aránzazu; Díaz Lucas, Silvia; Pérez Artieda, Miren Gurutze; Gómez Fernández, Marisol; Barrenechea Tartas, Edurne; Estadística, Informática y Matemáticas; Ingeniería; Ingeniería Eléctrica, Electrónica y de Comunicación; Estatistika, Informatika eta Matematika; Ingeniaritza; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren; Gobierno de Navarra / Nafarroako Gobernua; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa
The Public University of Navarre joined with Navarre Government has created the Women, Science and Technology Chair. This chair arises due to the plummeting tendency of the percentage of women in STEM degrees with the aim of reversing this trend. The programme of activities is defined throughout this contribution by six activities: a Theatre Play, a Poster Award on Final Degree/Masters Project, The 1st Week of Women, Science and Technology, the Promotion of Technical Degrees in schools and high-schools, a Workshop about Gender Stereotypes and the Fostering of Women among Science and Environment. Each activity gained great success and the preset goals were highly accomplished, especially, the 1st Week of Women, Science and Technology activity. The latter achieved a great success both in participation and in repercussion, contributing to visualize the role of women in science and technology.
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
Integration of second-life batteries in residential microgrids and fast charging stations
(IEEE, 2022) San Martín Biurrun, Idoia; Braco Sola, Elisa; Martín Castilla, Álvaro; Sanchis Gúrpide, Pablo; Ursúa Rubio, Alfredo; Ingeniería Eléctrica, Electrónica y de Comunicación; Institute of Smart Cities - ISC; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren; Gobierno de Navarra / Nafarroako Gobernua
The potential of batteries from electric vehicles to be given a second life in stationary applications could be starting to become a reality in few years. However, the technical and economic feasibility of such second-life batteries (SLBs) is still uncertain. In this context, this paper analyses the real operation of a SLB in three scenarios: two of residential microgrids with photovoltaic generation under different strategies, and a fast charging station for electric mobility. To this end, three energy management strategies are developed, the first of which seeks to maximise the self-consumption of a typical household with photovoltaic generation; the second, in addition to maximising self-consumption, presents a night-time charge and peak shaving of the contract power from the grid; and the last refers to an urban bus charging station in which the aim is to reduce the contract power from the grid. Experimental validation of SLB during more than three weeks of operation in each of the scenarios have proved the technical viability of these batteries in the applications analysed.
Open Access
Experimental assessment of first- and second-life electric vehicle batteries: performance, capacity dispersion, and aging
(IEEE, 2021) Braco Sola, Elisa; San Martín Biurrun, Idoia; 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; Gobierno de Navarra / Nafarroako Gobernua
Nowadays, the reuse of electric vehicle batteries is considered to be a feasible alternative to recycling, as it allows them to benefit from their remaining energy capacity and to enlarge their lifetime. Stationary applications, such as self-consumption or off-grid systems support, are examples of second-life (SL) uses for retired batteries. However, reused modules that compose these batteries have heterogeneous properties, which limit their performance. This article aims to assess the influence of degradation in modules from electric vehicles, covering three main aspects: performance, capacity dispersion, and extended SL behavior. First, a complete characterization of new and reused modules is carried out, considering three temperatures and three discharge rates. In the second stage, intra- and intermodule capacity dispersions are evaluated with new and reused samples. Finally, the behavior during SL is also analyzed, through an accelerated cycling test so that the evolution of capacity and dispersion are assessed. Experimental results show that the performance of reused modules is especially undermined at low temperatures and high current rates, as well as in advanced stages of aging. The intramodule dispersion is found to be similar in reused and new samples, while the intermodule differences are nearly four times greater in SL.
Open Access
Women, Science and Technology Chair—Promoting women’s careers in stem fields
(IEEE, 2023) Pérez Artieda, Miren Gurutze; Gómez Fernández, Marisol; Aranguren Garacochea, Patricia; Barrenechea Tartas, Edurne; Catalán Ros, Leyre; Díaz Lucas, Silvia; Jurío Munárriz, Aránzazu; Martínez Ramírez, Alicia; Millor Muruzábal, Nora; Ortiz Nicolás, Amalia; San Martín Biurrun, Idoia; Estadística, Informática y Matemáticas; Ingeniería; Ingeniería Eléctrica, Electrónica y de Comunicación; Estatistika, Informatika eta Matematika; Ingeniaritza; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren
The Chair of Women, Science and Technology of the Universidad Pública de Navarra (UPNA) aims to increase the participation of women in the fields of science and technology. Scientific culture and dissemination are the main focus of the different actions of the Chair. These activities include: the theatrical performance "Yo quiero ser científica", experimental workshops and conferences and exhibitions for all audiences and ages. More than 6.000 people have seen the play, more than 1.500 secondary school students have participated in the workshops and the audiovisual material has received more than 20.000 visits.
Open Access
Fast capacity and internal resistance estimation method for second-life batteries from electric vehicles
(Elsevier, 2023) Braco Sola, Elisa; San Martín Biurrun, Idoia; Sanchis Gúrpide, Pablo; Ursúa Rubio, Alfredo; Ingeniería Eléctrica, Electrónica y de Comunicación; Institute of Smart Cities - ISC; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa
The success of second-life (SL) Li-ion batteries from electric vehicles is still conditioned by their technical and economic viability. The knowledge of the internal parameters of retired batteries at the repurposing stage is key to ensure their adequate operation and to enlarge SL lifetime. However, traditional characterization methods require long testing times and specific equipment, which result in high costs that may jeopardize the economic viability of SL. In the seek of optimizing the repurposing stage, this contribution proposes a novel fast characterization method that allows to estimate capacity and internal resistance at various state of charge for reused cells, modules and battery packs. Three estimation models are proposed. The first of them is based on measurements of AC resistance, the second on DC resistance and the third combines both resistance types. These models are validated in 506 cells, 203 modules and 3 battery packs from different Nissan Leaf vehicles. The results achieved are satisfactory, with mean absolute percentage errors (MAPE) below 2.5% at cell and module level in capacity prediction and lower than 2.4% in resistance estimation. Considering battery pack level, MAPE is below 4.2% and 1.8% in capacity and resistance estimation respectively. With the proposed method, testing times are reduced from more than one day to 2 min per cell, while energy consumption is lowered from 1.4 kWh to 1 Wh. In short, this study contributes to the reduction of repurposing procedures and costs, and ultimately to the success of SL batteries business model.