Introduction to battery-management systems- COURSERA WEEK 04 QUIZ -1.4.5 ANSWERS

 

Practice quiz for lesson 1.4.5

Total points 3

1.

Question 1

Consider a cell having nominal voltage $v_{\rm nom}=3.3$V and total charge capacity $Q=25$Ah. If the BMS is designed to keep the cell's state of charge between 5% and 95%, and if the cell's present state of charge is 70%, what is the approximate remaining total energy in the cell (in Wh)? Round your answer to the nearest Wh.

1 / 1 point

54

Correct

Yes. Approximate remaining total energy is equal to $Q\times v_{\rm nom} \times \Delta z$ where $\Delta z = 0.70 - 0.05$.

2.

Question 2

Consider the HPPC test depicted on slide 3 of this lesson for $\Delta T=10$s and $I_{\rm chg}=I_{\rm dis}=10$A. If the cell voltages at times {0, 10$^+$, 20$^-$, 30$^-$, 30$^+$, 40$^-$, and 50} seconds are {3.8, 3.42, 3.4, 3.78, 4.15, 4.19, and 3.81}, what is the HPPC discharge resistance $R_{{\rm dis},\Delta T}$ of this cell (in m$\Omega$)? Round your answer to the nearest m$\Omega$.

1 / 1 point

40

Correct

Yes. Resistance = change in voltage (over the discharge pulse) divided by magnitude of current pulse.

3.

Question 3

Consider a cell having open-circuit voltage of 3.8V at its present state of charge, operational voltage limits of $v_{\rm min}=2.5$V and $v_{\rm max}=4.2$V, HPPC resistances of $R_{{\rm chg},\Delta T}=0.01\Omega$ and $R_{{\rm dis},\Delta T}=0.008\Omega$. What amount of (absolute) charge power (in W) does the HPPC method predict? Round your answer to the nearest W, and report a positive number.

1 / 1 point

168

Correct

Yes. The charge power is computed using the equation on slide 5 of this lesson.