Evaluation of particle dispersion behaviours in Lithium-ion battery slurry by electrical impedance spectra-tomography method

Abstract

This paper investigated the particle dispersion behaviours of Lithium-ion battery (LIB) slurry by using electrical impedance spectra-tomography (EIST) method from the perspective of experiment and simulation. In the experiment, an EIST system composed of Field—Programmable Gate Array (FPGA), multi-plexer, switch circuit and 8-electrode sensor is developed to measure the frequency response of LIB slurry under two different conditions, which are rotation speed n=0rpm with rotation time t=0min and n=100rpm with t=6min. In the simulation, four different geometry structure models, which are (a) Carbon Black (CB) linear formation, (b) CB aggregation, (c) CB & LiCoO₂ aggregation and (d) network dispersion, are established. Six frequencies, which are f=1 kHz, f=10 kHz, f=50 kHz, f=100 kHz, f=250 kHz and f=500 kHz, are used for the reconstructed conductivity images of LIB slurry in both the experiment and the simulation. The numerical simulation is used to verify the correctness of the experiment results. After combining the experiment and the simulation, it is concluded that the agglomeration behaviours of CB and LiCoO₂ particles appear within LIB slurry in the case of n=0rpm with t=0min, while CB path and part LiCoO₂ particles coated by CB particles appear in the case of n=100rpm with t=6min. Moreover, high frequencies are suitable to distinguish high conductive CB components from LIB slurry. Furthermore, the developed EIST system has the capability of monitoring particle dispersion behaviours in LIB slurry, which has the potential to be used for the on-line measurement of LIB slurry in order to improve the performance of LIB.