-
-
Notifications
You must be signed in to change notification settings - Fork 543
New issue
Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.
By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.
Already on GitHub? Sign in to your account
Cell-level State of Charge #2553
Comments
This will finally enable the much-requested feature "Charge until 98% SOC" |
Nice! To add to this, we typically calculate SoC as discharged capacity / RPT calculated capacity (or one minus that, to be precise). This way you can update it as the battery ages, but it gets trickier to calculate as it requires a separate simulation. |
I think all of the following are equivalent:
So any way we do it we have to pre-calculate something (
The capacity calculated by the "electrode SOH" model should give the same answer as the RPT without requiring a whole simulation (just solving an algebraic model) but let me know if you have a case where it doesn't |
Doesn't "electrode SOH" give the theoretical capacity (i.e. infinitely slow discharge)? RPT is usually at a given non-negligible C-rate (we typically use C/3). It should be possible write an analytical approximation for it using the SPMe model. |
Yes but in terms of calculating SOC we want the theoretical capacity, right? Since the SOC at the end of the C/3 discharge RPT should not be zero. I agree that the C/3 RPT is required to record the "C/3 capacity" at various cycles, but not to calculate the SOC |
Not so sure... We do it based on RPT (not sure about other people) and I think the nominal capacity is defined on a similar way. might be good to ask around? In any case, we can just go with theoretical capacity for the time being and we can always extend SOH models to account for RPT. |
Yes would be good to get more input on this. We can also have multiple "SOC" variables based on different capacity calculations |
I think using the RPT at 25oC to define the SoC is what's usually used with doing battery testing. The OCV at 100% SoC is taken to be the rested voltage after the CCCV charge and the OCV at 0% SoC is taken to be rested voltage after the CC discharge. I guess what's annoying about this definition of SoC is that it's dependent upon the cell resistance so if the cell ages then there will be different 100% and 0% OCV values.... Also it can only be calculated by actually running the RPT... |
Hi! Is its still open to work? I can explore though. |
As per my understanding following steps can be taken
|
Could anyone please tell me what's the meaning of x and y? |
x is stoichiometry in the negative electrode (goes from 0 to 1), y in the positive electrode |
We do not currently provide "State of Charge" as a variable, because it's not clear how to calculate this at the cell level:
(x - x_100)
Proposed solution
eSOH
calculation inParameterValues
class to define the parameters for the SOC submodelCaveat: this will be wrong as the cell degrades. We can figure out updating parameter values later
The text was updated successfully, but these errors were encountered: