Part of Cell capacity.

Not just CC discharge, but CC discharge + CCCV charge + full CC discharge. The difference between CCCV charge and full CC discharge should be subtracted from CC discharge (note: this difference is not Coulombic efficiency). This makes the measurement independent of the ralaxation time.

This process also allows to discriminate Cell self-discharge from Cell capacity fade after periods of calendar ageing [2]:

Related:

• ‣
• Dithering input voltage to get rid of hysteresis to achieve true 0% or 100% SoC - how does this "precise" procedure work with dithering?

References

[1] Measuring Reversible and Irreversible Capacity Losses on Lithium-ion Batteries (2016)

[2] ‣ (2018)