ECE 438/538 Project 3
Due Friday 3/5, 11:59 PM
Description
Recycle the BEV of your assignment from the last project and complete the following:
1) Size the battery pack (i.e., number of series and number of parallel) for your vehicle using all 2.2 Ah Li-
ion cells. Assume the nominal DC bus voltage about 400 V, the nominal battery cell voltage about 3.8 V,
and the BOL range of 200 km.
2) Simulate the battery cell terminal voltage vs. SOC under 0.5C, 1C, 2C, 5C, for the given battery. This
part has nothing to do with your particular vehicle choice.
3) Construct the efficiency map of the given battery at 0.8 SOC, with x-axis as motor RPM and y-axis as
motor torque, using the same motor from Project 2. Assume power electronics at a constant 95% efficiency.
4) Now including all the losses from the battery and power electronics, what is the new range this designed
battery pack from 1) can drive up to?
5) Suppose the battery pack from 1) starts from 0.9 SOC. What is the final SOC after one US06+SC03
combined drive cycle? How does the battery pack terminal voltage change over this drive cycle?

This project is total 40 points. Each calendar day late is 10% off the project grade.
Hints
For 1), you need to find the average vehicle power consumption rate in Wh/km. To do this, take the total
motor energy consumption over the US06+SC03 combined drive cycle divided by the total distance – watch
for units. The distance is an integration of speed over time. For this step, assume ideal batteries and power
electronics so that all the battery energy goes into the motor input energy, which was already calculated
from Project 2.
For 2), the given battery Voc (open circuit voltage) and Rstat (series resistance) both depend on SOC’s. You
may use the command “interp1()” to interpolate the values based on the actual SOC. Note SOC is 1-DOD.
For 3), each motor RPM and torque combination requires a specific power from the battery pack. This
battery power includes the motor power losses, so it is not simply torque times speed but should consider
the motor efficiency calculated from Project 2. Then assume a 95% efficiency for the power electronics
between the battery pack and the motor. Given the designed battery pack from 1) and the required power,
you should be able to solve for the required current using the quadratic equation from class. Subsequently
you can find the battery loss and efficiency.
For 4), you should be able to plot the required battery power and energy over the drive cycle. From there
you can find the new Wh/km value.
For 5), the SOC should track the energy consumption already calculated in part 4), just normalized. At each
time stamp, the required battery power and the SOC at that moment will calculate the battery current and
terminal voltage.



Base Codes
Base codes are available in “Proj3.m”. In this relatively more practical battery model, the internal resistance
also depends on SOC instead of being constant. If you have a question about how the codes are written
(e.g., syntax or special functions), use MATLAB “help” command or find answers on related Q&A forums
online.
Submission Requirement
For 1), plot the cumulative motor energy consumption vs. distance over the combined US06+SC03 drive
cycle. In the report, show basic math leading to the design of the battery pack, i.e., number of series and
parallel cells.
For 2), plot all four traces (0.5C, 1C, 2C, 5C) on one figure.
For 3), plot the battery efficiency map. The battery efficiency map should be in similar format as the motor
efficiency map (i.e., color bar, contour line, etc.). This time be sure to add the embedded numbers (90, 91,
etc.) inside the contour lines so that it is obvious to tell the efficiency boundaries.
For 4), plot the required battery power vs. time, and the required battery energy vs. distance. Show basic
math leading to the new vehicle range.
For 5), plot the SOC vs. time over the combined drive cycle, and the battery pack terminal voltage vs. time.

All of the above plots and math are to be pasted into one single document for submission. MATLAB figures
are to be exported in .jpg or .png format before pasting into the document, i.e., no screenshots of the
MATLAB scopes.
For each plot, write a brief paragraph to describe what information you can extract from the figure. Does
everything make sense? If there is discrepancy, what could be the possible causes?

On Canvas under “Assignments” - “Project 3”, submit:
i) All source codes .m individually;
ii) All plots and written paragraphs in a single .pdf document.
Upload each file separately, NOT in a .zip folder. All files should be named in the format of
“LASTNAME_Firstname_xxx”. “xxx” stands for a specific file name of your choice. If there is a “main” .m
file, please clearly mark that in the file name. All models must be able to run by clicking the run button.
Files are subject to plagiarism check against other students’ submissions, including this year’s and all
previous years’.








































































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