Study of Li-ion cells accelerated test based on degradation path

Abstract

According to the characteristics of long life, high reliability of Li-ion cells, a constant stress accelerated degradation test method is put forward to assessing reliability and predict lifetime of Li-ion cells. First, FMEA analysis is carried out on Li-ion cells, and the most common failure mode is capacity reduction which the temperature is the most important accelerated stress. Second, the accelerated degradation model and the parameters degradation path model of Li-ion cells are determined, and the accelerated degradation test of Li-ion cells is designed through the analysis of sensitive stresses. With the method of Bartlett statistics, the degradation mechanism consistency boundary is determined on the base of parameter degeneration path in order to obtain the accelerated stress level. The reliability of Li-ion cells is assessed based on pseudo lifetime.