I am running an aging simulation at 25 deg and 35 degC with following options,
model = pybamm.lithium_ion.SPM(
{
“cell geometry”: “arbitrary”,
“thermal”: “lumped”,
“SEI”: “solvent-diffusion limited”,
“SEI porosity change”: “true”,
“lithium plating”: “partially reversible”,
“lithium plating porosity change”: “true”, # alias for “SEI porosity change”
“loss of active material”:“stress-driven”
},
)
after 1500 charge/discharge cycles, overall capacity degradation is slower at 35 degC than 25degC. when i analysed the individual components i observed,
at 35 degC, SEI loss and plating loss are higher than at 25 degC. porosity reduction is more.
at 25 degC, loss of active material is higher than at 35 degC. active material fraction reduction is more.
overall 25deg shows a higher capacity loss than 35 deg C.
is the behavior correct or am i missing something.
will be grateful for any insights.
regards.
Hi @Thiyaga,
SEI loss should be higher at high temperature.
Stress-driven loss of active material should be higher at low temperature.
Plating loss should be very small at both 25 and 35 degrees.
For the OKane2022 parameter set, I found that the degradation was slowest at 25 degrees, fastest at 5 degrees and 45 degrees was in between. But that was with cracking enabled, which I notice you haven’t done.
I don’t think you should enable cracking. Instead, it would be very interesting to see if the temperature dependence between 5 and 45 degrees is different without it!
Good luck! Simon
hi @DrSOKane ,
thanks a ton for the kind response.
yes, as you mentioned,
SEI loss is high at 35 degC than 25 degC. lithium plating the same between both and stress driven active material loss is more with 25 degC runs. I looked at your coupled degradation paper and can relate the governing equations for SEI loss and Li plating. how to understand the equations(22, 17a,17b and 17c) of stress-driven active material loss(which parameter varies with temperature). ran the simulation with 5 and 45 degrees. observed the degradation was fastest at 5 degrees, and slowest at 45 degrees and 25 degrees was in between ( i ran for 1500 cycles with a dynamic discharge current profile, till 600 cycles 25 degrees was slowest then it crossed the 45 degrees SOH curve and 45 degrees became slowest)
Hello Thiyaga,
I’m trying to replicate the same issue, but I wanna see how the capacity fades per cycle at different temperatures (25, 45, 55, 65).
So, I’m wondering which models you used?
hi Yasir,
sorry for the late response. I used the above mentioned model. As mentioned in this thread, with low temperatures ( ~ below 30 deg C) loss of active material will be high and with higher temperatures(above 35 deg C) SEI losses would be high. you may find optimum temperature around 30-35 degC where the degradation would be the lowest(assuming NMC chemistry). this window will shift depends on the cathode chemistry and you need to tne your aging parameters accordingly. for with LFP, low temperature is not as bad as like for NMC.
please refer this paper,
Journal of The Electrochemical Society, 2020 167 120532
Degradation of Commercial Lithium-Ion Cells as a Function of
Chemistry and Cycling Conditions
Yuliya Preger,1,,z Heather M. Barkholtz,1 Armando Fresquez,2 Daniel L. Campbell,3 Benjamin W. Juba,4 Jessica Romàn-Kustas,4 Summer R. Ferreira,5 and
Babu Chalamala1,
Hope this helps.
