Analysis and Modeling of Calendar Aging and Cycle Aging of LiCoO2/Graphite Cells

Lithium-ion batteries are used in a wide range of applications.However,their cycle life suffers from the problem of capacity fade,which includes calendar and cycle aging.The effects of storage time,temperature and partial charge-discharge cycling on the capacity fade of Li-ion batteries are investigated in this study.The calendar aging and cycle aging are presented based on the storage and cycling experiment on LiCoO2/graphite cells under different storage temperature and different ranges of state of charge(SOC).Based on the measurement data,a one-component and a double-component aging model are presented to respectively describe the capacity fade caused by calendar and cycle aging.The calendar aging of LiCoO2/graphite batteries is mainly affected by temperature and SOC during the storage.Mean SOC and change in SOC(ΔSOC) are the main factors affecting battery degradation during cycling operation.