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 (ASOC) are the main factors affecting battery degradation during cycling operation.