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Figure 25.7: History of Maximum Temperature in the Domain

3. Save the case and data files (unit_battery.cas.gz and unit_battery.cas.gz).

File → Write → Case & Data...

25.4.5. Postprocessing

In this section, postprocessing capabilities for the MSMD battery model solution are demonstrated.

1.Display the contour plot of the phase potential for the positive electrode.

Results → Graphics → Contours → Edit...

a.In the Contours dialog box, in the Options group box, enable Filled.

b.From the Contours of drop-down list, select User Defined Scalars... and Potential Phi+.

c.Click the Toggle Tree View button next to the Surfaces filter and from the drop-down list, select

Surface Type (under Group by).

d.From the Surfaces selection list, under Wall, select tab_p, wall_active, and wall_p.

e.Click Display and close the Contours dialog box.

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Figure 25.8: Contour Plot of Phase Potential for the Positive Electrode

2.In a similar manner, display the contour plot of the phase potential for the negative electrode.

Results → Graphics → Contours → Edit...

a. In the Contours dialog box, in the Options group box, enable Filled.

b.From the Contours of drop-down list, select User Defined Scalars... and Potential Phi-.

c.From the Surfaces selection list, select tab_n, wall_active, and wall_n.

d.Click Display and close the Contours dialog box.

Figure 25.9: Contour Plot of Phase Potential for the Negative Electrode

3.Display the contour plot of the temperature.

Results → Graphics → Contours → Edit...

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a.In the Contours dialog box, in the Options group box, enable Filled.

b.From the Contours of drop-down list, select Temperature... and Static Temperature.

c.Select Wall in the Surfaces selection list.

The surfaces listed under Wall are automatically selected in the Surfaces list.

d.Click Display and close the Contours dialog box.

Note

Use the Axes dialog box to set the precision for the colormap labels.

Figure 25.10: Contour Plot of Temperature

4.Display the vector plot of current density.

Results → Graphics → Vectors → Edit...

a. In the Vectors dialog box, select current-density-j from the Vectors of drop-down list.

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b.Select User Defined Memory... and Magnitude of Current Density from the Color by drop-down list.

c.Click the Toggle Tree View button next to the Surfaces filter and from the drop-down list, select

Surface Type (under Group by).

d.From the Surfaces selection list, select Wall.

e.In the Options group, enable Draw Mesh and in the Mesh Display dialog box, set the mesh display options as desired.

f.Click Display and close the Vectors dialog box.

Figure 25.11: Vector Plot of Current Density

5.Save the case file as ntgk.cas.gz. You will use this saved case later to treat electric short-circuits.

6.Repeat the simulation for the following charge rates and time steps:

Make the following changes in the model’s settings:

a.In the MSMD Battery Model dialog box, under the Model Options tab, specify the value listed in the above table for the C-Rate.

b.Modify the output filename for the voltage_vp-rfile report file by entering ntgk-C-Rate.out for Output File Base Name in the corresponding Edit Report File dialog box, where C-Rate is the value of the battery discharge rate. (For example, for C-Rate = 0.5 C, you will enter ntgk-0.5c.out for the filename).

c.Similarly, modify the output filename for max_temp-rfile by entering max-temp-C-Rate.out for

Output File Base Name in the corresponding Edit Report File dialog box.

d. Initialize and run the solution for the number of the times steps specified in the above table.

Note

The Fluent solver will stop either after completing the specified number of time steps or when the Min. Stop Voltage condition is reached.

7. Display the discharge curves for the positive tab for the different discharge rates.

Results → Plots → File...

a. In the File XY Plot dialog box, click Load....

b. In the Select File dialog box, change File of Types to All Files (*), click ntgk-0.5c.out and click OK.

c.Under Legend Entries, in the lowest text-entry box, enter 0.5c and click Change Legend Entry.

d.Do the same for ntgk-1c.out and ntgk-5c.out and change their legend entries accordingly.

e. In the Legend Title text-entry box, enter Discharge Rate.

f.Click Plot and close the File XY Plot dialog box.

Note

Use the Axes dialog box to set the precision for the plot axes.

The Figure 25.12: NTGK Model: Discharge Curves (p. 849) shows the discharge curves for different discharge rates in the function of time.

Figure 25.12: NTGK Model: Discharge Curves