Meaning
Ratio of the discharge capacity to the charge capacity during a specific recovery cycle after a period of storage or degradation. The coulombic recovery measures the return of usable electrochemical capacity after self-discharge or elevated temperature storage has occurred. It defines the boundary between permanent and reversible capacity loss in secondary battery cells.
Capacity Restoration
Secondary cells experience both reversible and irreversible losses during storage, and this metric isolates the recoverable fraction. Reversible loss occurs due to slow self-discharge which can be reversed by a standard recharge cycle. Irreversible loss results from chemical degradation of the active materials or electrolyte, which permanently reduces the maximum energy storage of the cell.
Low capacity recovery signals that the cell chemistry is undergoing parasitic reactions, which would shorten the operational life of the battery pack.
Diagnostic Value
Sourcing decisions rely on this parameter to verify the stability of cell chemistry under simulated transport conditions. High values indicate a stable solid electrolyte interphase that does not consume excessive lithium during periods of inactivity. This measurement allows engineers to compare the shelf-life characteristics of different cathode formulations.
Testing Protocol
Standardized testing procedures require a baseline discharge followed by a defined storage duration under controlled temperature and state of charge. After the storage period, the cell undergoes a complete charge and discharge sequence to determine the restored capacity. These measurements must be executed at a constant temperature to eliminate thermal influences on cell impedance.
