Online identification of internal impedance of Li-ion battery using ternary-sequence injection

    Research output: Chapter in Book/Report/Conference proceedingConference contributionScientificpeer-review

    4 Citations (Scopus)


    The internal impedance of a battery has been shown to change as a function of state-of-charge (SOC) and state-of-health (SOH). Therefore, online impedance measurements can provide useful information for SOC- and SOH-estimation algorithms. Broadband injections techniques such as pseudo-random-binary-sequence (PRBS) are attractive alternative for replacing conventional electrochemical-impedance-spectroscopy (EIS) which is very slow for online battery impedance measurements. However, non-linearities of batteries have a negative impact on the measurement results obtained by the PRBS for which the identified system is assumed to be linear. This paper demonstrates the use of ternary-sequence excitation signal for battery impedance measurements. Appropriately designed ternary-sequence can efficiently capture the linear component of the impedance by canceling out the distortion caused by the non-linear parts. The presented method can be used for rapid impedance measurements and thus, as a valuable tool in online SOC- and SOH-estimation algorithms. Experimental measurements are shown from a Lithium-Iron-Phosphate (LiFePO4) battery cell.
    Original languageEnglish
    Title of host publicationThe 10th Annual IEEE Energy Conversion Congress and Exposition (ECCE 2018)
    Subtitle of host publicationSeptember 23 – 27, 2018, Portland, Oregon, USA
    Number of pages7
    ISBN (Electronic)978-1-4799-7312-5
    Publication statusPublished - 6 Dec 2018
    Publication typeA4 Article in conference proceedings
    EventIEEE Energy Conversion Congress and Exposition - Portland, United States
    Duration: 23 Sept 201827 Sept 2018

    Publication series

    ISSN (Electronic)2329-3748


    ConferenceIEEE Energy Conversion Congress and Exposition
    Country/TerritoryUnited States

    Publication forum classification

    • Publication forum level 1


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