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Application of Electrochemical Impedance Spectroscopy (EIS) on Module Level Li-ion Batteries for Echelon Utilization

Savca, Alexandru (2022) Application of Electrochemical Impedance Spectroscopy (EIS) on Module Level Li-ion Batteries for Echelon Utilization.

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Abstract:The rising demand for lithium-ion batteries in the EV sector brings up ecological issues and the need for reusing the second-life lithium-ion batteries for other purposes. Thus, the battery modules have to be tested and sorted according to their state of health before being assembled in battery packs and used in their second-life application. Electrochemical impedance spectroscopy is a powerful and effective tool for characterization of batteries state of health. Due to the need of fast testing and the tendency to perform the EIS measurements on module level, it is meaningful to assess the validity of EIS on module level and if the SOH can be retrieved in the same way as for individual cells. In this paper, EIS is performed on a lithium-ion battery module with an unknown history and state of health. Curve fitting technique was used to fit the measured EIS spectra to an equivalent circuit model (ECM) to extract the circuit elements. The contribution of individual cell elements to the whole module elements was investigated and the elements sensitive to SOH were determined. The charge transfer resistance, double layer capacitance and the ohmic resistance of the individual cells were accurately reflected on the module’s ECM elements. The ohmic resistance and the charge transfer resistance showed correlation to the SOH of the cells and the module.
Item Type:Essay (Bachelor)
Faculty:EEMCS: Electrical Engineering, Mathematics and Computer Science
Subject:53 electrotechnology
Programme:Electrical Engineering BSc (56953)
Link to this item:https://purl.utwente.nl/essays/92423
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