A comparative study of battery balancing strategies for different battery operation processes

Zheng, Ling; Zhu, Jianguo; Wang, Guoxiu

doi:10.1109/itec.2016.7520204

Cited by 11 publications

(7 citation statements)

References 13 publications

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“…There are many types of SoH estimation techniques broadly classified as model-based estimation and estimation using data analysis and prediction. Model based SoH estimation is carried out by creating electrochemical and equivalent models of the cell/battery circuit and analyzing it by subjecting to changes in parameters [41][42]. Data driven methods focus on collecting the data carried out from cycling testing and later using these data to understand a pattern that can be later used to train models to predict SoH [43].…”

Section: Soh Estimationmentioning

confidence: 99%

Secondary Life of Electric Vehicle Batteries: Degradation, State of Health Estimation Using Incremental Capacity Analysis, Applications and Challenges

John,

Kudva,

Jayalakshmi

2024

IEEE Access

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Electric vehicles (EVs) have created a revolution in sustainable transportation. The number of EV users has increased significantly within a short period globally. EVs running largely on the battery source require large-capacity battery packs to handle the range anxiety. The primary lifetime of such batteries in EV applications is said to end when their capacity drops to 80% of their initial capacity. This is termed as the end of-life of these batteries. These batteries can still be utilized for secondary applications based on their remaining capacity. Batteries undergo many degradations throughout their lifecycle which affects their capacity. This paper carries out a detailed study on the major degradation factors like solid electrolyte interphase and lithium plating which results in loss of lithium inventory. These affect the capacity of the battery in the long run. Remaining useful capacity must be accurately estimated to identify if the cells are useful for the next phase or must be recycled. Many estimation techniques are available with attention rising towards data derivational methods due to their accuracy and their sensitivity towards battery degradation which thereby makes it easy to track them. Incremental capacity analysis is one such method which is discussed in detail in this paper. The method starts from the initial stage of data extraction and extends to the training set of the models. This method is greatly beneficial as it can reveal the deviations in battery behavior with the help of the valley peak locations and alterations in the slope. The quantitative insights make it an advantageous technique in the field of battery health monitoring and diagnostics. These are discussed in detail and validated by experimental analysis and results. This paper also discusses the market prospects, developments, various ageing mechanisms in batteries, applications, comparison with other estimation techniques and challenges related to secondary life applications. The complete analysis of the estimation method along with the detailed steps also aims to serve as a foundation for the upcoming developments and research in this field.INDEX TERMS Electric vehicle, incremental capacity analysis, second life of EV battery, state of health estimation.

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Section: Soh Estimationmentioning

confidence: 99%

Secondary Life of Electric Vehicle Batteries: Degradation, State of Health Estimation Using Incremental Capacity Analysis, Applications and Challenges

John,

Kudva,

Jayalakshmi

2024

IEEE Access

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“…When batteries of different capacities are connected in series to charge and discharge, a single current loop is formed for all cells, and the same current flows. Additionally, the state of charge is different for each battery [3,4].…”

Section: Characteristics Of Series-connected Batteriesmentioning

confidence: 99%

“…One is based on the voltage of the battery, and the other is based on the capacity of the battery. Cell balancing based on capacity is a burden because the capacity of each cell connected in series in the BMS must always be calculated [3,4]. Therefore, in the field, balancing based on voltage is applied.…”

Section: Introductionmentioning

confidence: 99%

Effect of Capacity Variation in Series-Connected Batteries on Aging

Yun

Kee

2022

Batteries

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Batteries are used in various combinations in various fields. Research on single-cell batteries is well underway and is approaching a stabilization phase. However, problems caused by battery combinations are still insufficiently studied. The purpose of this study was to investigate the cause of fires due to gradual damage in a large-capacity energy storage system (ESS). In the paper Energy Storage System Safety Operation Plan by Preventing Overcharge During Relaxation Time, which was based on the fact that most fires in large-capacity energy storage devices occurred during the diastolic period, it was proven that the inflow of compensation current due to a voltage imbalance in the cell was the cause. The total amount of compensation current is determined by the voltage deviation of the battery. Batteries connected in series have different rates of aging due to differences in their capacities. Thus, with use, the total amount of compensating current continues to increase until a fire occurs. In this study, by analyzing the effect of battery-capacity deviation on the aging of individual cells, it was confirmed that the capacity deviation increased as the battery was used, resulting in an increase in the total amount of compensation current. In addition, if a solution to the problem is presented and the proposed solution is applied, the allowable range of battery-capacity deviation will be widened. We used Matlab 2009a, assuming a real environment. Using Simulink, problems were identified through simulation, improvement measures were suggested, and the proposed method was verified via simulation.

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“…These include voltage-based balancing, SOC balancing and capacity-based balancing, which is based on the actual remaining capacity of the cells [88]. Voltage-based balancing is the easiest to realize because of the directly measured cell voltages, but has some disadvantages [88,89]. It is not suitable for many cell types, including LICs, because the relationship between voltage and charge is not linear.…”

Section: Selection Of Deviating Cellsmentioning

confidence: 99%

“…In the middle SOC range the voltage curve is very flat. As shown in Figure 3.15, a large difference in charge can therefore only result in a small difference in voltage [89,90]. Furthermore, voltagebased balancing, such as in [91], suffers from so-called overbalancing when the cell capacities and internal resistances are different.…”

Section: Selection Of Deviating Cellsmentioning

confidence: 99%

Possibilities and limitations of active battery management systems for lithium-ion batteries

Ziegler¹

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(English) Lithium-Ion Batteries (LIBs) are being used in more and more areas of application. At the same time, their chemical composition and their designs are constantly evolving. Major developments are also taking place in the field of Battery Management Systems (BMSs), which are essential for the safe operation of LIBs. The focus is on intelligent charge redistribution between individual cells, called Active Balancing (AB). This thesis deals with the possibilities and limitations of AB. An empirical long-term experiment provides new insights into the ageing behaviour of batteries that are actively balanced during their entire service life. The main objective of this work is to to demonstrate influences on the ageing behaviour of batteries that are still unknown at present. A literature study shows that previous work in this area is often based on theoretical approaches and rarely has a functional proof through measurement results. Most significant statements from literature are examined. These include the increase in discharge capacity, energy efficiency and service life associated with AB, as well as lower parameter variation of the individual cells installed in the battery. Before starting the empirical experiment, the current state of the art is captured and a universal AB topology is selected from a large number of known systems. The operating behaviour as well as the balancing algorithms are explained in detail in order to be able to understand the influences occurring during the ageing of the batteries. The ageing experiment itself is a comparison test between commercial Passive Balancing (PB) and the novel AB. Two identical battery packs are aged under uniform conditions, but with the two different BMSs mentioned above. At the end of the ageing process, the battery packs are disassembled and the parameters of all individual cells are determined for further investigation. The main contribution of this work is the proof of effects through AB, especially with large battery loads. Both the increase in discharge capacity and the service life are demonstrated. The work shows how parameter variation of individual cells can be made visible during operation. It also presents diagnosis and calculation methods. The energetic efficiency of the batteries cannot be increased, since the self-consumption of the power electronics of the AB system is always higher than with PB. However, the overall efficiency of the battery increases due to an increase in capacity and an extension of the service life. The thesis also shows that with lower battery loads, the use of AB is not beneficial any more or may lead to negative effects. In such applications conventional PB is sufficient. The results obtained during pack ageing are additionally substantiated and extended by the measurement results of the individual cells. At the end of the thesis, all results and contributions are summarised. Suggestions for optimisation as well as further research ideas are presented as a possible starting point for further scientific studies. (Català) Les bateries d’ions de liti (Lithium Ion Batteries, en anglès) s’usen en més aplicacions. Al mateix temps, la seva composició química i dissenys estan en evolució constant. Els sistemes de gestió del bateries (Battery Management Systems, en anglès), que són essencials per l’operació de les LIB, també estan en constant evolució. El focus principal està en la distribució intel·ligent de càrrega elèctrica entre cel·les individuals, l’anomenat balanceig actiu (Active Balancing, en anglès). Un assaig empíric, de llarga durada, com el dut a terme en aquest treball, dona molt informació en el procés d’envelliment de les cel·les durant tota la seva vida. El principal objectiu d’aquest treball és demostrar les influències encara desconegudes en el procés d’envelliment de les cel·les. L’estudi de la literatura mostra que el treball previ en aquesta àrea està sovint basat en aproximacions teòriques i estranyament ensenya resultats empírics que ho corroborin. En aquest treball s’examinen la majoria de presumpcions que es poden trobar a la literatura. Aquestes inclouen l’increment en la capacitat, l’eficiència energètica i la vida útil associada a un balanceig actiu de les cel·les, així com la reducció de la variació dels paràmetres de cada cel·la en una bateria. Abans de procedir amb l’experiment empíric, es revisa l’estat de l’art en els aspectes fonamentals per aquest estudi. També se selecciona una tipologia de sistema de balanceig actiu per tal de realitzar l’experiment. El treball detalla el procediment d’operació així com l’algoritme de balanceig actiu implementat per tal d’entendre els fenòmens que influencien la degradació de les cel·les durant la seva vida. L’experiment d’envelliment és una comparació entre un sistema de balanceig passiu (Passive Balancing, en anglès) i un de balanceig actiu. Per això s’escullen dues bateries idèntiques, però gestionades diferentment per dos sistemes de gestió diferents. Al final de l’assaig, les bateries es desmunten i s’analitza cada cel·la de forma individual per tal de determinar-ne els seus paràmetres i el seu envelliment. La principal contribució d’aquest treball es el demostrar els efectes del balanceig actiu , sobretot en bateries amb una càrrega elevada. El treball demostra que el balanceig actiu millor gla capacitat de la bateria i la vida útil. El treball també mostra com la variació dels paràmetres de les cel·les es pot fer visible durant la seva operació. També presenta nous mètodes de diagnosi i càlcul d’aquests paràmetres. L’eficiència energètica de les bateries no es pot augmentar degut al consum propi i les pèrdues del sistema de balanceig actiu basat en electrònica de potencia. Si que augmenta l’eficiència global de la bateria, ja que augmenta la seva capacitat i la vida útil. El treball també mostra que en bateries sotmeses a baixa càrrega, el balanceig actiu no aporta cap avantatge respecte el balanceig passiu. Fins i tot en algunes situacions, els efectes del balanceig actiu són negatius. En aquestes aplicacions, es recomana l’ús d’un sistema de balanceig passiu. Els resultats obtinguts durant l’assaig de la bateria queden reforçats quan es fa l’anàlisi de cada cel·la de forma individual. Al final del treball, es resumeixen tots els resultats a més de proporcionar suggereixes per la optimització així com possibles línies de futures investigacions

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A comparative study of battery balancing strategies for different battery operation processes

Cited by 11 publications

References 13 publications

Secondary Life of Electric Vehicle Batteries: Degradation, State of Health Estimation Using Incremental Capacity Analysis, Applications and Challenges

Secondary Life of Electric Vehicle Batteries: Degradation, State of Health Estimation Using Incremental Capacity Analysis, Applications and Challenges

Effect of Capacity Variation in Series-Connected Batteries on Aging

Possibilities and limitations of active battery management systems for lithium-ion batteries

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