Li-ion battery (LIB) failure induced by mechanical damage can lead to electrical and chemical hazards together with fire, which can result in danger to life, the environment. The damage occurred by mechanical deformation can be consider as the origin for internal short-circuit (ISC) in the battery mostly due to the direct contact between anode and cathode electrodes. To mitigate these issues and caution the user about ISC and thermal runaway events, the development of a diagnostic method to identify the damage mechanism under mechanical deformation and corresponding electrical behavior is essential. The onset of short circuits often characterized by rapid drop in voltage or by increase in temperature which may be enough for regular safety testing to suggest the absence of any potentially dangerous events. However, it is challenging to predict the early-stage initiation of ISC failure. Herein, we demonstrate resistance measurement by electrochemical impedance spectroscopy (EIS) as an indicator for the detection of an internal short circuit of LIBs. The Impedance behavior of Li-ion battery at different mechanical deformation level is evaluated through proper equivalent circuit model with multi-frequency and alternating voltage or current signal. The fitted results reveal that cathode-electrolyte interface resistance can be used to predict the onset of ISC under mechanical loading conditions. The increase is ohmic resistances can be attributed to the damage of electrodes including delamination, thinning, micro crack formation and sever fracture. Deformation of the pouch cell may lead to delamination and thereby to an increase of the effective charge transfer path and the reduction of total charge transfer surface area, which could, in turn, cause an increase of ohmic resistance. During indentation, distance between the cell components continues to reduce. The cell layers are squeezed, and number of layers subjected to deformation are increases with the increase in punch displacement. Continues indentation pushes the active material out of the area under the indentor causes stretching of current collectors. With such continues compression, localized thinning appears in the cell layers closest to the indentor. The separator undergoes tear failure due to the rise in local strain level as a result of extensive localize thinning that causes direct contact between anode and cathode which leads to ISC. Occurrence of these successive events can be predicted by assessing the shift of Nyquist plot with the increase in level of mechanical deformation. The obtained results demonstrate that impedance spectroscopy, together with a precise modeling, provides information about the events related to of ISC.


Electrochemical Impedance Spectroscopy (EIS) for the Prediction of Deformation Induced Internal Short Circuit in Li-Ion Batteries

Division / Sponsors: 
Aerospace, Bioengineering, Applied Mechanics, Design Engineering Division, Advanced Energy Systems, Manufacturing Engineering Division, Noise Control and Acoustics, Nondestructive Evaluation, Diagnosis, and Prognosis (NDPD), Nuclear Engineering Division, Process Industries Division, Fluids Engineering, Heat Transfer, Materials, Microelectromechanical Systems, Safety Engineering and Risk Analysis, Computers & Information in Engineering


Paper Proceedings: https://asmedigitalcollection.asme.org/IMECE/IMECE2020/volume/84478

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