Capacity loss or capacity fading is a phenomenon observed in rechargeable battery usage where the amount of charge a battery can deliver at the rated voltage decreases with use.
[3] Capacity fading in Li-ion batteries occurs by a multitude of stress factors, including ambient temperature, discharge C-rate, and state of charge (SOC).
Chemical mechanisms of degradation in a Li-ion battery dominate capacity loss at low C-rates, whereas, mechanical degradation dominates at high C-rates.
For the first 500 equivalent full cycles mean SOC is found to have a major effect on the capacity fade of cells as compared to ΔSOC.
However, towards the end of the testing (600~800 equivalent cycles) ΔSOC becomes the major factor affecting the capacity loss rate of the cells.