SOH-aware active cell balancing strategy for high power battery packs

Probstl, Alma; Park, Sang-Young; Narayanaswamy, Swaminathan; Steinhorst, Sebastian; Chakraborty, Samarjit

doi:10.23919/date.2018.8342048

Cited by 24 publications

(11 citation statements)

References 19 publications

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“…Switched shunt resistors [56] are most commonly used, but it is also possible to use fixed resistors which are always connected to the cells [57]. The fixed resistors cause the pack to naturally balance over time, since the highest voltage cells will have higher resistor current, but there are always losses even when the pack is fully balanced making it a rather undesirable method [58]. In the switched shunt resistor method [56], each cell is associated with a balancing resistor and a switch to connect it to the cell, typically a MOSFET.…”

Section: A Dissipative Balancing Methodsmentioning

confidence: 99%

Lithium-Ion Battery Pack Robust State of Charge Estimation, Cell Inconsistency, and Balancing: Review

2021

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Lithium-Ion battery packs are an essential component for electric vehicles (EVs). These packs are configured from hundreds of series and parallel connected cells to provide the necessary power and energy for the vehicle. An accurate, adaptable battery management system (BMS) is essential to monitor and control such a large number of cells. Series and parallel connected cells also experience different production and operational conditions, which makes it challenging for the BMS to ensure the safe operation of each individual cell. The main functions of the BMS include battery state estimation, cell balancing, thermal management, and fault diagnosis. Robust estimation of the state of charge (SOC) is crucial for providing the driver with an accurate indication of the remaining range. This paper presents the state of art of battery pack SOC estimation methods along with the impact of cell inconsistency on pack performance and SOC estimation. Cell balancing methods, which are necessary due to cell inconsistencies, are discussed as well. Four categories of pack SOC estimation methods are presented, including individual cell, lumped cell, reference cell, and mean cell and difference estimation methods. The SOC estimation methods are compared in terms of algorithm type, computational load, and engineering effort to help practitioners decide which method best fits their application.INDEX TERMS Lithium-ion battery packs, battery management systems, electric vehicles, cell inconsistency, state of charge, cell balancing.

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Section: A Dissipative Balancing Methodsmentioning

confidence: 99%

Lithium-Ion Battery Pack Robust State of Charge Estimation, Cell Inconsistency, and Balancing: Review

2021

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“…The cell voltage equalization will take place in either under passive or active balancing mode, wherein the former the excessive charge is dissipated as heat, while in the latter the excessive charge from highly charged cells is moved to the cells with less charge, thus making them stronger cells to support the weaker ones [33]- [35]. In the BMS, the cell balancer charger operates in three modes namely the cell charging balancing mode, the cell discharging balancing mode, and the idle mode by controlling the driving signals of the primary and secondary switches [36], due to the fact that EVs batteries are not always used to their full capacity in every driving cycle and thus it is not necessary to keep the SOC balanced at all times [37]. Fig.…”

Section: Battery Cell Balancingmentioning

confidence: 99%

“…Therefore, the charge is lost or discharged through a resistor to the air rendering this method to be less efficient and generates a lot of heat. The conventional cell balancing approaches are passive where the excess charge of cells with high SOC is dissipated as heat across a resistor, resulting in reduced energy efficiency [65], [66]. However, this method is good for low-cost system applications in which no active control is utilized to equalize.…”

Section: ) Passive Cell Balancingmentioning

confidence: 99%

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Review of Battery Cell Balancing Methodologies for Optimizing Battery Pack Performance in Electric Vehicles

Omariba

Zhang

Sun³

2019

IEEE Access

218

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Batteries are gaining entry into every home and office for they are widely used because of their variant benefits. However, these batteries are prone to failure caused by charge imbalance in the batteries connected in either series or parallel, which can sometimes be catastrophic and hence they require to be properly monitored in a real-time manner. There exist many battery balancing schemes which are broadly grouped into either passive or active schemes. All these schemes have their own advantages and disadvantages, and hence it is upon the user to decide on which scheme will best work for them. However, research has proven that the hybrid scheme will be the best as it couples the benefits of all schemes. This study will review the various battery cell balancing methodologies and evaluate their relationship with battery performance. At present there are a few studies tackling the mechanical vibration of battery balancing performance. This study shows that battery balancing performance during long-term should be evaluated from various temperature and vibration frequencies.INDEX TERMS Battery cell balancing, electric vehicles, hybrid schemes, and performance optimization.

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“…Cell imbalance is a main significant factor in large battery packs which degrades the performance of the battery to be qualified by state of health (SOH) of battery 28‐30 . The weakest cell (lowest SOH of cell) in a set of series‐connected cells dominated the overall string strength which causes safety issues and thermal runaway when discharging the battery pack below the limit 31‐33 . Classification of cell balancing into two methods such as passive cell balancing and active cell balancing which is explained in Figure 1 based on the battery SOC 34,35 …”

Section: Li‐ion Battery Cell Balancingmentioning

confidence: 99%

Overview of cell balancing methods for Li‐ion battery technology

Hemavathi

2020

Energy Storage

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Li‐ion batteries are influenced by numerous features such as over‐voltage, undervoltage, overcharge and discharge current, thermal runaway, and cell voltage imbalance. One of the most significant factors is cell imbalance which varies each cell voltage in the battery pack overtime and hence decreases battery capacity rapidly. To increase the lifetime of the battery pack, the battery cells should be frequently equalized to keeps up the difference between the cells as small as possible. There are different techniques of cell balancing have been presented for the battery pack. It is classified as passive and active cell balancing methods based on cell voltage and state of charge (SOC). The passive cell balancing technique equalizing the SOC of the cells by the dissipation of energy from higher SOC cells and formulates all the cells with similar SOC equivalent to the lowest level cell SOC. The active cell balancing transferring the energy from higher SOC cell to lower SOC cell, hence the SOC of the cells will be equal. This review article introduces an overview of different proposed cell balancing methods for Li‐ion battery can be used in energy storage and automobile applications.

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SOH-aware active cell balancing strategy for high power battery packs

Cited by 24 publications

References 19 publications

Lithium-Ion Battery Pack Robust State of Charge Estimation, Cell Inconsistency, and Balancing: Review

Lithium-Ion Battery Pack Robust State of Charge Estimation, Cell Inconsistency, and Balancing: Review

Review of Battery Cell Balancing Methodologies for Optimizing Battery Pack Performance in Electric Vehicles

Overview of cell balancing methods for Li‐ion battery technology

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