A cycle is defined as the moment when the cell returns to the starting point after undergoing a charge and discharge process that involved both the upper and lower cut-off voltage limits as defined by the operation. Since except during cell testing (especially cell aging testing), a cycle is rarely seen, the driving profile is often characterized using equivalent full cycles:

Equivalent full cycle (EFC): It is used to classify any cycle or any charge or discharge in terms of the charge throughput of a full cycle. For example, a cycle between 50 and 100% State of charge (SoC) (so starting at 50% SoC, charging to 100% and then discharging to 50% SoC again) is equivalent to 0.5 EFC

Half cycle: The real driving profile can be broken up into a series of half cycles based on different algorithms such as the rain flow algorithm, etc. Classifications for half cycles can be quite specific such as each time the current drops to zero, a half cycle is finished. Or if the SoC signal changes direction.

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