Project 2
Q.1.Using MATLAB/Simulink and the drive cycle from the attached Excel sheet, find-
- The max heat generation of the battery
- The SOC of the battery at 2 *104second of the battery operation
| Time | Time Step | Battery Current |
| 00:00.4 | 0.1 | -0.9632 |
| 00:00.5 | 0.2 | -0.952 |
| 00:00.6 | 0.3 | -0.9072 |
| 00:00.7 | 0.4 | -0.9632 |
| 00:00.8 | 0.5 | -1.0304 |
| 00:00.9 | 0.6 | -0.9632 |
| 00:01.0 | 0.7 | -1.0304 |
| 00:01.1 | 0.8 | -1.008 |
| 00:01.2 | 0.9 | -0.9856 |
| 00:01.3 | 1 | -0.9632 |
| 00:01.4 | 1.1 | -0.9184 |
| 00:01.5 | 1.2 | -0.9296 |
| 00:01.6 | 1.3 | -0.9296 |
| 00:01.7 | 1.4 | -0.9296 |
| 00:01.8 | 1.5 | -0.9184 |
| 00:01.9 | 1.6 | -0.9408 |
| 00:02.0 | 1.7 | -0.896 |
| 00:02.1 | 1.8 | -0.9072 |
| 00:02.2 | 1.9 | -0.9072 |
| 00:02.3 | 2 | -0.9408 |
| 00:02.4 | 2.1 | -0.9296 |
| 00:02.5 | 2.2 | -0.9296 |
| 00:02.6 | 2.3 | -0.9968 |
| 00:02.7 | 2.4 | -0.9968 |
| 00:02.8 | 2.5 | -0.9408 |
| 00:02.9 | 2.6 | -0.9408 |
| Battery resistance | 2 milli ohm |
Consider the battery resistance is 0.5 mOhm, delta time is 0.1 and entropic factor is 2
ANS: To calculate the maximum heat generation in the battery bank, you can use the formula:
Q= I^2*R*t
Where,
Q is the heat generated
I is the battery current
R is the battery resistance
t is the time
Since the entropic heat is assumed to be twice the joule heat, the total heat(Qtotal) is the sum of the joules heat(Qjoules) and the entropic heat(Qentropic).
Qtotal =Qjoules+Qentropic
Qentropic= 2* Qjoules
Now,
Maximum heat generation = Max*Qtotal .......(Qtotal =Qjoules+Qentropic)
When the maximum current passes then maximum heat is generated.
The maximum current is passing at the time interval of 120 Sec. and the current value is 0.896 amp.
Maximum heat generation= Joule heat + Entropic heat
= I^2*R*t + 2*Jolues heat
= I^2*R*t + 2* I^2*R*t
= (0.896^2*0.5*120)+2*(0.896*0.5*120)
= 48.16896 + 2*(48.16896)
= 144.50688
Maximum heat generation=144.50688 Joules
b) The SOC of the battery at 2 *104second of the battery operation
SOC = State of Charge is defines the how energy is usable for application
SOC = Q / Qmax
where,
Q = Available capacity
Qmax = Overall capacity
for the simulation model following blocks are used
Generic Battery - Implements a generic battery model for the most popular battery types. Temperature and aging (due to cycling) effects can be specified for the Lithium-Ion battery type. Take the initial state of charge is 50 %
Controlled current source - Converts the Simulink input signal into an equivalent current source. The generated current is driven by the input signal of the block. You can initialize your circuit with a specific AC or DC current. If you want to start the simulation in steady-state, the block input must be connected to a signal starting as a sinusoidal or DC waveform corresponding to the initial values.
Bus Selector -This block accepts a bus as input which can be created from a Bus Creator, Bus Selector or a block that defines its output using a bus object. The left list box shows the elements in the input bus. Use the Select button to select the output elements. The right list box shows the selections. Use the Up, Down, or Remove button to reorder the selections. Check 'Output as virtual bus' to output a single bus.
Signal Builder Block -To use any type of signal till 129 stop time.
Scope- to Display the output graph.
Powergui -Set simulation type, simulation parameters, and preferences.
Model:
Result:
The maximum heat generation of the battery:
The Max heat generated in which the current flows in and out i.e., charge and discharge due to internal resistance and chemical reaction during charging and discharging of the battery the heat is generated of 144.50688 Joules.
The SOC of the battery at 2 *104second of the battery operation:
The battery charging is done till 129 seconds after that no current is passed through the battery, so the SOC of the battery is constant from 129 seconds to 208 seconds.