Hysteresis is a permanent deviation of the Cell terminal voltage from the Cell open-circuit voltage opposite in effect to the current being applied to the cell (increases the cell voltage during charge current and decreases during discharge current, relative to the OCV) which remains even after the current is withdrawn from the cell (and thus, hysteresis is different from the ohmic voltage drop due to Cell internal resistance).
There are instantaneous and dynamic parts of hysteresis.
Hysteresis is caused by polarisation of electrode material, Cell internal resistance drop (??), and the difference in the intercalation energies.
These all contribute to the potential "envelope" on the plateau that contribute to energy efficiency drop in the battery.
Ballpark hysteresis value: 0.1V (see below).
Dithering input voltage to get rid of hysteresis to achieve true 0% or 100% SoC
Hysteresis magnitude (both instantaneous and dynamic components) generally decreases with the rise of battery temperature:
Related:
‣ 2.3.8