Design and use of multisine signals for Li-ion battery equivalent circuit modelling. Part 1: Signal design

Abstract

Permanent WRAP URL:http://wrap.warwick.ac.uk/79240 Copyright and reuse:The Warwick Research Archive Portal (WRAP) makes this work by researchers of the University of Warwick available open access under the following conditions. Copyright © and all moral rights to the version of the paper presented here belong to the individual author(s) and/or other copyright owners. To the extent reasonable and practicable the material made available in WRAP has been checked for eligibility before being made available.Copies of full items can be used for personal research or study, educational, or not-for-profit purposes without prior permission or charge. Provided that the authors, title and full bibliographic details are credited, a hyperlink and/or URL is given for the original metadata page and the content is not changed in any way. 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. AbstractThe Pulse Power Current (PPC) profile is often the signal of choice for obtaining the parameters of a Lithium-ion (Li-ion) battery Equivalent Circuit Model (ECM). Subsequently, a drive-cycle current profile is used as a validation signal. Such a profile, in contrast to a PPC, is more dynamic in both the amplitude and frequency bandwidth. Modelling errors can occur when using PPC data for parametrisation since the model is optimised over a narrower bandwidth than the validation profile. A signal more representative of a drive-cycle, while maintaining a degree of generality, is needed to reduce such modelling errors.In Part 1 of this 2-part paper a signal design technique defined as a pulsemultisine is presented. This superimposes a signal known as a multisine to a discharge, rest and charge base signal to achieve a profile more dynamic in amplitude and frequency bandwidth, and thus more similar to a drive-cycle. * Corresponding author. Email: Dhammika.Widanalage@warwick.ac.uk. Address: WMG, University of Warwick, Coventry, CV4 7AL, UK. Telephone: 0044 24765 28191. Preprint submitted to Journal of Power SourcesMay 25, 2016The signal improves modelling accuracy and reduces the experimentation time, per state-of-charge (SoC) and temperature, to several minutes compared to several hours for an PPC experiment.

A brief review on key technologies in the battery management system of electric vehicles

“…Battery electric models mainly include electrochemical model [6][7][8][9], reduced-order model [10][11][12][13], equivalent circuit model [14][15][16][17] and data-driven model [18][19][20]. For electrochemical model, Rahman et al [6] claimed that the battery electrochemical model should have the abilities to capture the spatiotemporal dynamics of battery concentration, the electrode potential for each phase and the BulterVolmer kinetic to control intercalation reaction.…”

Innovative Method for Simultaneous Electrical and Thermal Parametrisation of Automotive Batteries

“…ECMs are a relatively simple lumped parameter model ubiquitous in estimation algorithms for describing lithium ion batteries electrochemical behaviour in real time [30][31][32][33]. Whilst this does increase the measurement calculation complexity, it improves the model accuracy [28]. Performing a least squares fit to the whole voltage response is also more robust than a simple division of two measurements.…”

“…Furthermore the battery is excited with a more dynamic current signal, both in terms of amplitude and frequency, compared to the HPPC technique [28,34]. This PM signal is a periodic signal that is generated by summing sinusoids, providing the researcher with the flexibility to alter the amplitude spectrum and harmonic content.…”

“…The linear ECM is a second-order RC network model commonly used to decribed the terminal voltage of lithium ion batteries [35]. The nonlinear over-voltage function accounts for the Tafel relation in electrochemical kinetics, where a higher over-potential is required to sustain a given current density at low SoCs and temperatures [28]. The third component characterises the OCV and hysteresis as per the method proposed in [36].…”

“…A new procedure known as pulse-multisine (PM) has been developed [28] that combines a multisine and a pulse signal, which allows for concurrent electrochemical and thermal parametrisation. This reduces the number of experiments required to develop the model.…”