What determines the lifetime (decrease in capacity) of a Li Ion accumulator ?
To my current investigation this is determined by the charge / discharge cycles.
So the function for "age" should be:
age = ac current amplitude * time
This would mean when the accumulator is used where the dc current is zero, but the ac current amplitude is high (rectagular 1C pp for example, frequency >1Hz), the user can not determine "charging" or "discharging", but the accumulator should age quite quickly (300 effective charge cycles in 25 days ). Obviously the Li Ion should not be fully charged in this example, so I assume it stays at .5C charge.
Is this assumption correct ? Does it depend on ac current frequency ? Is there a model to determine the "age" of a Li Ion accumulator ? Is there some further information concerning this ?