Hi all,
I am trying to estimate battery degradation using existing equations obtained from current literature. However, when it comes to Ah throughput there is a confusion about how we calculate it and what each parameter represents. One of the equations found in multiple papers is:
Ah(throughput)=(Number of cycles)*(DOD) *(Cell capacity).
So the question is which DOD we use during a discharging event? the final one? and how we calculate the number of cycles? For example the SoC window is 10%-90%, and the battery is discharged from 90% to 70%.
if anyone has to recommend a paper that clearly addresses these issues or has a clear answer please let me know
thanks a lot!
Nikolas
Hi Nikolas,
considering the given equation, I think its purpose is to calculate the total utilized amount of capacity at each cycles. In other words, DOD is a relative number now that shows a window of total amount of charge consumed in every cycle. Thus, if you run discharges between DOD = 10%-90% (from almost fully charged to almost discharged state), the DOD value in the quoted equation should be 0,8 (80%).
The cyclical aging can be mainly maintained by tracking the discharged capacity hence, it should be enough to count only the discharged capacity at each cycle.
This approach also allows to work with partial charge-discharge cycles such as UDC, WLTP and other practical usage patterns instead of ideal full charges and discharges. There would be often dynamic data in practice.
I hope, I could help.
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