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Lithium Ion Battery, NCA/Graphite, cannot implement forced convection into continuous solver steps

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Hi everyone,

I have a li-ion battery model, and I succeed to implement it into continuous solver steps. However, it only works in natural convection like this, but not in the original example forced convection.

In the success model, which I used heat output flux as expelling heat by air naturally, and turned off spf laminar flow and air in the heat transfer physics. When putting things back it bothered me a lot for the model has been changed many times, which led to study and solver configurations reverted to default, thus cancelled some critical settings.

Those critical settings include 1) use ONLY "spf laminar flow" in "Stationary solver" 2) use ONLY "liion" in "Current Distribution Initialization" 3) use ALL liion, ht, nitf1 BUT spf in "Time Dependent Solver"

Now it's running well but only in the first stage (when speaking of stages, it means CC-charge, CV-charge, R1-rest, CC-discharge, and R2 rest.) I have some "not going to next stage" or "not converged" issues, since I have no idea and tried unsuccessfully with the study and solver configurations.

I'm not sure if I have to duplicate each Stationary and CDI for 5 stages I am using, or maybe I can use it repeatedly without duplicating it (just like in natural convection setup). Besides, what should I use for initial conditions and to combine them up? I've tried many of the settings but none of them work (at least the ones I've tried.)

The attached fc_view.png is the model picture with forced convection. The battery itself is in right of the block while in the left there is an empty of its external geometry. The top plane of the z axis is where air enters at v_in of 1[m/s] The bottom plane is where air leaves. (They both colored purple) The top and bottom of the battery body or x axis in green are explicitly named walls. The two sides colored orange walls are the symmetry planes to the spf module. The mph file is in the attached.

Best Regards,

CH



0 Replies Last Post 17 nov 2020, 11:15 GMT-5
COMSOL Moderator

Hello Chun Huai Hsu

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