Learning Forum

[hamed.heidari]

Hello,

I have created a 3D Li-ion single-cell battery model in ANSYS Fluent, and I am simulating the temperature distribution during a constant current (CC) discharge process. The model matches my experimental data quite well in terms of voltage response and overall temperature change over time.

However, I have encountered a discrepancy in the temperature distribution. In my experiments, the highest temperature is observed near the tabs. But in the simulation—under adiabatic boundary conditions—the hottest region appears near the bottom of the cell.

I have reviewed the ANSYS documentation (specifically this tutorial:
ANSYS Battery Tutorial), and it also shows the hottest area near the bottom and the coolest near the tabs.

I have double-checked all settings, including enabling Joule heating, but the reported Joule heating value remains zero throughout the simulation. This seems suspicious and may explain the mismatch.

Could you please advise if there is something I might be missing or doing incorrectly with respect to Joule heating or other relevant setup parameters?

Thank you in advance for your support.

[AG]

It is critical to use anisotropic thermal conductivity for cell active material to get correct temperature distribution in cell.

Check for missing contact resistances present at tab - cell connection which generally case for a heat rise near tab. 

Tutorial you are reffering to, is indeed having very small heat generation (Joule heating) in tab and higher heat generation (Echem heating) in active cell region. Which explains the temperature distribution. 

Reported joule heting will be zero for cell active zone. Check for echem heat source instead. 

[hamed.heidari]

Thank you very much for your response. I am using anisotropic thermal conductivity for the cell’s active material. I have tried different contact resistance values at the tabs (e.g., 1e3 and 1e6), but I still obtain zero Joule heating. I applied these contact resistances to the uppermost surface of the tab, which I have designated as the external contact surface.

In my geometry, I have one part containing three bodies—the active material and the two tabs—rather than three separate parts. Could this cause a problem? These two points (the placement of the contact resistance and the part/body setup) are where I suspect the issue might be. Could you please confirm whether this configuration is correct?