Current density and state of charge inhomogeneities in Li-ion battery cells with LiFePO4 as cathode material due to temperature gradients

Fleckenstein, Matthias; Bohlen, Oliver; Roscher, Michael A.; Bäker, Bernard

doi:10.1016/j.jpowsour.2011.01.043

Cited by 225 publications

(138 citation statements)

References 20 publications

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“…24. As a consequence of thermal gradients, current density and SoC inhomogeneities occur within the cell, which cause localised ageing [29] and reduce the efficiency and lifespan of the battery. To reduce localised ageing, original equipment manufacturer (OEMs) aim to achieve 3-5°C temperature gradient within the battery pack.…”

Section: Temperature Gradientsmentioning

confidence: 99%

See 1 more Smart Citation

Large format lithium ion pouch cell full thermal characterisation for improved electric vehicle thermal management

Grandjean

Barai

Hosseinzadeh

et al. 2017

Journal of Power Sources

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A note on versions:The version presented here may differ from the published version or, version of record, if you wish to cite this item you are advised to consult the publisher's version. Please see the 'permanent WRAP url' above for details on accessing the published version and note that access may require a subscription.  Gradients across the cell thickness can be larger than across the cell surface. Similar heat distribution between charge and discharge scenarios. Self heating increases available capacity at low temperatures *Highlights (for review) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 AbstractIt is crucial to maintain temperature homogeneity in lithium ion batteries in order to prevent adverse voltage distributions and differential ageing within the cell. As such, the thermal behaviour of a large-format 20 Ah lithium iron phosphate pouch cell is investigated over a wide range of ambient temperatures and C rates during both charging and discharging. Whilst previous studies have only considered one surface, this article presents experimental results, which characterise both surfaces of the cell exposed to similar thermal media and boundary conditions, allowing for thermal gradients in-plane and perpendicular to the stack to be quantified. Temperature gradients, caused by self-heating, are found to increase with increasing C rate and decreasing temperature to such an extent that 13.4 ± 0.7% capacity can be extracted using a 10C discharge compared to a 0.5C discharge, both at -10°C ambient temperature. The former condition causes a 18.8 ± 1.1˚C in plane gradient and a 19.7 ± 0.8˚C thermal gradient perpendicular to the stack, which results in large current density distributions and local state of charge differences within the cell. The implications of these thermal and electrical inhomogeneities on ageing and battery pack design for the automotive industry are discussed.

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Section: Temperature Gradientsmentioning

confidence: 99%

“…As a consequence of thermal gradients, the cell does not age uniformly and an ageing gradient occurs inside the cell [29,30], reducing the efficiency and lifespan of lithium ion batteries. Strong thermal gradients can also lead to deformations of the jelly roll in cylindrical cells [22,31].…”

Section: Introductionmentioning

confidence: 99%

Large format lithium ion pouch cell full thermal characterisation for improved electric vehicle thermal management

Grandjean

Barai

Hosseinzadeh

et al. 2017

Journal of Power Sources

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“…In addition to calendar age (t age ) and cycle number (N) which are known to cause degradation in proportion to t z [13] and N [14], respectively; temperature [4,23], SoC [24], ∆SoC [25] and current [26] are also known accelerators of battery degradation. The effects of these stress factors-based on published literature-at the microscopic level along with their quantifications in the P2D model are presented using flow charts below.…”

Section: Expected Parameter Changes Resulting From Battery Degradationmentioning

confidence: 99%

Characterising Lithium-Ion Battery Degradation through the Identification and Tracking of Electrochemical Battery Model Parameters

Perera²,

et al. 2016

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Lithium-ion (Li-ion) batteries undergo complex electrochemical and mechanical degradation. This complexity is pronounced in applications such as electric vehicles, where highly demanding cycles of operation and varying environmental conditions lead to non-trivial interactions of ageing stress factors. This work presents the framework for an ageing diagnostic tool based on identifying and then tracking the evolution of model parameters of a fundamental electrochemistry-based battery model from non-invasive voltage/current cycling tests. In addition to understanding the underlying mechanisms for degradation, the optimisation algorithm developed in this work allows for rapid parametrisation of the pseudo-two dimensional (P2D), Doyle-Fuller-Newman, battery model. This is achieved through exploiting the embedded symbolic manipulation capabilities and global optimisation methods within MapleSim. Results are presented that highlight the significant reductions in the computational resources required for solving systems of coupled non-linear partial differential equations.

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“…Furthermore, temperature gradients within cells through the central plane have been reported to also contribute to accelerated degradation [38,39]. Parts of the cell at elevated temperatures are expected to have a lower resistance, allowing more current to flow through it, in turn heating up more via a positive feedback process between unique layers that are electrically connected in parallel, and localised parts in the same layer.…”

Section: Hp Cycle Validationmentioning

confidence: 99%

Duty-cycle characterisation of large-format automotive lithium ion pouch cells for high performance vehicle applications

Kellner

Worwood

Barai

et al. 2018

Journal of Energy Storage

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A B S T R A C TThe long-term behaviour of lithium ion batteries in high-performance (HP) electric vehicle (EV) applications is not well understood due to a lack of suitable testing cycles and experimental data. As such a generic HP duty cycle (HP-C), representing driving on a race track is validated, and six NMC graphite cells are characterised with respect to cycle-life. To enable a comparison between the HP-EV environment and conventional road driving, two test groups of cells are subject to an experimental evaluation over 200 duty cycles that includes a representative HP-C and a standard duty cycle from the IEC 62660-1 standard (IECC). After testing, both test groups display increased energy capacity, increased pure Ohmic resistance, lower charge transfer resistance an extended OCV operating window. The changes are more pronounced for cells subject to the HP-C. Based on capacity tests, Electrochemical Impedance Spectroscopy (EIS), pseudo-OCV tests, and Pulse Multisine Characterisation, it is concluded that the changes in cell characteristics are most likely caused by cracking of the electrode material caused by high electrical current pulses. With continued cycling, cells cycled with the HP-C are expected to show degradation at an increased rate due to raised temperatures, and more pronounced electrode cracking.

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Current density and state of charge inhomogeneities in Li-ion battery cells with LiFePO4 as cathode material due to temperature gradients

Cited by 225 publications

References 20 publications

Large format lithium ion pouch cell full thermal characterisation for improved electric vehicle thermal management

Large format lithium ion pouch cell full thermal characterisation for improved electric vehicle thermal management

Characterising Lithium-Ion Battery Degradation through the Identification and Tracking of Electrochemical Battery Model Parameters

Duty-cycle characterisation of large-format automotive lithium ion pouch cells for high performance vehicle applications

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