Results of Screening over 200 Pristine Lithium-Ion Cells

Barreras, Jorge Varela; Raj, Trishna; Howey, David A.; Schaltz, Erik

doi:10.1109/vppc.2017.8331054

Cited by 4 publications

(2 citation statements)

References 14 publications

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“…To model this, firstly, at the beginning of life, cells are expected to have slightly different capacities and resistances. Barreras et al [8] screened a batch of 200 new Kokam cells and found that the measured capacities and resistances were normally-distributed with relative standard deviations of 0.4% and 2.5% respectively, so we also assumed normally-distributed initial capacities and resistances with these standard deviations. Secondly, as the cells degrade, differences between them increase, as shown by Harris et al [9] and Baumhöfer et al [10].…”

Section: Model Parameterisationmentioning

confidence: 99%

“…This assumes that all cells behave identically, while in reality it has been shown that even cells from the same production batch are slightly different to one another. Barreras et al [8] screened over 200 cells and found that the standard deviations for the initial capacity and resistance were 0.4% and 2.5% respectively. As cells degrade, these differences increase-when Harris et al [9] aggressively cycled 24 cells, the 'worst' cell only had 45% remaining capacity while the 'best' cell still had 85% at the end of the experiment.…”

Section: Introductionmentioning

confidence: 99%

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Digital twin of a MWh-scale grid battery system for efficiency and degradation analysis

Reniers¹,

Howey²

2022

Preprint

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Large-scale grid-connected lithium-ion batteries are increasingly being deployed to support renewable energy roll-out on the power grid. These battery systems consist of thousands of individual cells and various ancillary systems for monitoring and control. Although many studies have focused on the behaviour of single lithium-ion cells, the impact of system design choices and ancillary system controls on long-term degradation and efficiency of system, containing thousands of cells, has rarely been considered in detail.Here, we simulate a 1 MWh grid battery system consisting of 18900 individual cells, each represented by a separate electrochemical model, as well as the thermal management system and power electronic converters.Simulations of the impact of cell-to-cell variability, thermal effects, and degradation effects were run for up to 10000 cycles and 10 years. It is shown that electrical contact resistances and cell-to-cell variations in initial

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Section: Model Parameterisationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Digital twin of a MWh-scale grid battery system for efficiency and degradation analysis

Reniers¹,

Howey²

2022

Preprint

Self Cite

View full text Add to dashboard Cite

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A Monte Carlo simulator to investigate cell‐to‐cell deviation in a grid‐tied battery pack

Wang

Davidson

et al. 2022

IET Power Electronics

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Battery energy storage systems (BESSs) are commonly used in smart grids. Voltage deviation or imbalance among cells generally exists in multi-cell battery packs. This work presents a study of the voltage deviation-related phenomena observed during the operation of a grid-tied BESS, Willenhall Energy Storage System (WESS), including the voltage deviation changes during full range cycle and the cut-off mechanism activated by it. Electroimpedance spectroscopy measurements and equivalent circuit modelling were conducted on the same type of cell as that used in WESS to obtain cell-equivalent circuit parameter distributions (the standard deviation and mean). Cell voltage deviation in a WESS-sized battery pack (> 21k cells) was studied using Monte Carlo simulation through a proposed cell level battery simulator. Both experiments and simulations reveal that high cell voltage deviation emerges at the low and high state-of-charge zones where the cell internal resistance has a large value and large extent of deviation.

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Systematic Approach for the Test Data Generation and Validation of ISC/ESC Detection Methods

et al. 2023

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Various methods published in recent years for reliable detection of battery faults (mainly internal short circuit (ISC)) raise the question of comparability and cross-method evaluation, which cannot yet be answered due to significant differences in training data and boundary conditions. This paper provides a Monte Carlo-like simulation approach to generate a reproducible, comprehensible and large dataset based on an extensive literature search on common assumptions and simulation parameters. In some cases, these assumptions are quite different from field data, as shown by comparison with experimentally determined values. Two relatively simple ISC detection methods are tested on the generated dataset and their performance is evaluated to illustrate the proposed approach. The evaluation of the detection performance by quantitative measures such as the Youden-index shows a high divergence with respect to internal and external parameters such as threshold level and cell-to-cell variations (CtCV), respectively. These results underline the importance of quantitative evaluations based on identical test data. The proposed approach is able to support this task by providing cost-effective test data generation with incorporation of known factors affecting detection quality.

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Results of Screening over 200 Pristine Lithium-Ion Cells

Cited by 4 publications

References 14 publications

Digital twin of a MWh-scale grid battery system for efficiency and degradation analysis

Digital twin of a MWh-scale grid battery system for efficiency and degradation analysis

A Monte Carlo simulator to investigate cell‐to‐cell deviation in a grid‐tied battery pack

Systematic Approach for the Test Data Generation and Validation of ISC/ESC Detection Methods

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