State of Health (SoH)

State of health (SoH) describes the current condition of a battery cell or storage system compared to its original state, usually expressed as a percentage of its original capacity. Unlike state of charge (SoC), which indicates the short-term charge level, SoH reflects the long-term aging of the cells from use and time. A declining SoH value signals when a battery storage system is approaching the end of its economically usable life.