| 摘要 |
PROBLEM TO BE SOLVED: To obtain an evaluation method and an evaluation device for lithium ion secondary battery in which formation conditions for SEI film can be determined at an early stage of the aging process of a lithium ion secondary battery. SOLUTION: The evaluation method for lithium ion secondary battery is provided with steps, wherein the frequency characteristics of impedance of the lithium ion secondary battery of evaluation object are measured; a step in which, based on the frequency characteristics, optimal value of parameter of an equivalent circuit model of the lithium ion secondary battery is determined by a fitting process; a process in which, among the parameters of which the optimal value is determined, a Rpe parameter value which reflects the forming condition of the SEI film is extracted, and a step in which, based on the variation tendency of the Rpe parameter values extracted for each measurement with the passage of time, existence of normal formation of the SEI film is determined. COPYRIGHT: (C)2011,JPO&INPIT |
