Some experimental data [1] shows self-discharge rate at 60 °C of 20% per month for a new cell and 5% per month for a cell whose capacity is already faded 30-40% (see Cell capacity fade).

[3] shows that new cells with silicon-graphite anode and NMC cathode discharge by approx. 0.2% per month when stored at 25 °C and 10% SoC and 0.4% per month when stored at 90% SoC.

Electrodes can swell, increasing pressure on separator and, as a consequence, increasing the self-discharge rate of the cell. Possible causes:

• Very thin dendrites cause "soft short circuit" because of their high resistance. These dendrites is the vehicle for self-discharge. [2]

Increase of the self-discharge rate is one of the symptoms of Cell degradation.

Cell self-discharge rate is one of the Cell parameters.

References

[1] Global Model for Self-discharge and Capacity Fade in Lithium-ion Batteries Based on the Generalized Eyring Relationship (2018)

[2] ‣

[3] Reversible self-discharge and calendar aging of 18650 nickel-rich, silicon-graphite lithium-ion cells (2019)