Deterioration Analysis of DC internal resistance by “Current-Rest-Method” using the “Four-Electrode Cell ” for LIB

After 500 hours of the floating test, the C.R.M. resistance of the cell at around 3.6 V in the discharge process doubled from 23.1 Ω to 39.6 Ω. We investigated what caused the increase in the resistance by separating the C.R.M. resistance of the cell using the “four-electrode cell”. At the sixth current-rest point in the discharge process, the C.R.M. resistance of the positive electrode increased by 16.3 Ω, while that of the negative electrode increased by only 1.3 Ω. The “ohmic component ” in the C.R.M. resistance of the positive electrode remarkably increased in the low voltage region compared to that of the negative electrode. The separation of resistance using the “four-electrode cell ” allows us to clarify deterioration factors in cells easily