Project 2
PROJECT:2
AIME:
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
Using MATLAB/simulink and the drive cycle from the attached excel sheet, find-
- The max heat generation of the batterY:
|
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:-
Calculation:-
Heat generated = Joules heat + Entropy heat
From ohms law we know that
The heat Generated in the Reisitor is-
- Directly praportion to the square of the current flowing through it
- Directly praportion to the resistance
- Directly praportion to the time for which the current flows through it.
Entropy Heat:
The heat generation due to entropy change inside a battery occurs when electro chemical reactions are performed. The entropy heat is reversible heat resulting from change in open circuit voltage with respect to temperature at two Electrodes.
Given data
Battery resistance = 0.5 mOhm = 0.0005 Ohm
V=IR
Power
P=V*I=I^2*R
Heat
H=I^2*R*t
where,
P=power
V=voltage
I=current
R=resistance
H=heat
T=time
Batterry resistance = 0.5m ohm = 0.0005ohm.
Maximum heat generated = maximum joule heat + 2(maximum joule heat)
Imax = -0.896 A
tmax = 1.7 sec
R = 0.0005 ohm
maximum joule heat = (Imax)^2 * R * tmax
P = (-1.008)2*0.5*0.8
=0.46 J
Now we use the above formuela
Joule heat + Entropy heat
0.406 + 2
=2.406 J
2.The SOC of the battery at 2 *104second of the battery operation:-
Simulink Model:
- 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 most popular battery types. Temperature and aging (due to cycling) effects can be specified for Lithium-Ion battery type.
- 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 listbox shows the elements in the input bus. Use the Select button to select the output elements. The right listbox 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 208 stop time.
- Scope- to Display the output graph
- Powergui -Set simulation type, simulation parameters, and preferences
The following blocks are used for the simulation model:
Generic Battery: Uses a generic battery model for the most common types of batteries. For each type of Lithium-Ion battery, the effects of temperature and ageing (caused by cycling) can be set.
Controlled current source: Turns the Simulink input signal into a current source with the same value. The signal coming into the block is what makes the current flow.
Controlled current source: If you want the simulation to start in a steady state, you must connect the block input to a signal that starts as a sinusoidal or DC waveform that matches the initial values.
Bus Selector: This block can get a bus from a Bus Creator, a Bus Selector, or a block that uses a bus object to define its output. The items on the input bus are shown in the left listbox. To choose the output elements, click the Select button. The choices are shown in the box on the right. To change the order of the choices, click the Up, Down, or Remove button. If you check "Output as virtual bus," only one bus will be sent out.
Signal Builder Block - To use any kind of signal until stop time.
Scope: to show the graph of the output
Powergui - Set the type of simulation, its parameters, and your preferences.
Output:-
- This current cycle is given as the input to the model through the drive cycle input block i.e excel file wich is given in the question
- Here the drive cycle stop time is 2*104 i.e 208sec
- so the simulation run time is 208sec
- Here the output of the drive cycle is given to the current controlled source which is connected to the battery as a load
- so here the battery is dicharged accroding to this siginal given by the data which is excel data input drive cycle data
- Here the power gui block is rquired for any simulation of the simulink model
- It mainly used to store the equivalent simulink circuit which represents the state space model
- The ouput of a battery is given to the scope through the bus selector the bus selector outputs the battery siginals to the scope.
The SoC refers to the State of Charge of the battery, which is the capacity percent left in the battery which can be used. It a very improtent thing which teles about the battery status which helps in using the battery in a proper manner.
The SoC can be measued in different ways. Some of them are listed below
- Voltage Translation Method (VT)
- Coulamb counting method (CC)
- Combination of VT and CC
The VT and CC has its own advantages ad disadvantages so to get accurate value we have to use the Combination of VT and CC.
Voltage Translation Method (VT):
It is measued by Open Circut Voltge of the battery and compared it with the Data sheet of the battery and SoC is estimated. It cannot used while the battery is in operation.
Coulamb counting method (CC):
It is calculated by the formula
SoC = total charge input / Max capacity of the battery
Total charge input = charge current * time (H)
Combination of VT and CC:
To avoid the calculation of SoC both the Voltage Translation Method (VT) and Coulamb counting method (CC) are used combinedly.
Charge and Discharge command or Siganal to run the Constant Currnet source, so that the current will flow in and out according to the signal. + signal to chagrge and - for discharge. The total time for the run is taken as 2*104 = 208 sec
The Current signal is taken with the time of 0 to 208 sec with 1 sec step as
22 -22 -7 -6 39 -27 -42 76 31 14 53 -29 75 46 -12 33 79 -50 -41 3 41 -25 2 4 -18 -24 -42 55 22 80 3 -1 69 93 1 46 89 50 -23 -49 -43 21 -2 83 -14 24 -13 -50 21 87 -22 15 32 -10 96 13 -22 5 -46 76 59 43 -42 79 78 65 -23 -47 -36 -44 -1 72 21 28 62 79 13 100 85 20 74 17 41 32 12 -18 78 -31 -1 -3 -28 -32 -26 -18 81 -16 -25 76 12 61 -16 0 96 97 71 95 -6 -23 -39 -50 -22 -48 65 -13 5 -7 -16 -13 37 63 -45 -47 -28 -1 46 27 -17 -49 97 56 1 -25 -11 -47 89 24 79 32 66 56 32 30 -18 -22 86 58 2 -18 -39 -25 42 10 52 21 57 22 -36 18 44 -45 86 30 52 78 -16 -14 73 -46 -35 39 47 -19 84 -33 -45 73 -10 37 36 51 67 99 5 87 67 -34 8 -7 72 16 36 -45 0 -25 57 -37 53 65 -9 -29 -43 44 51 -11 55 -6 72 74 58
Graph:
Result and Conclusion:
1. The max heat generation of the battery
The Max heat generated in which the current flowing 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 generates of 2.0006823936 Jouls
2. The SOC of the battery at 2 *104second of the battery operation:
Initially the battery SoC is taken as 50% so it started and according to the current signal i.e., charge and discharge, if the charhing happens the battery SoC is increasing and when it is discharging SoC is decreasing.
Result:-
The above graph gives the results of SOC voltage and current
Here we operated the soc of battery at 2*104
THE SOC OF THE BATTERY AT 208 SEC IS 99.5%.
Conclusion:-
The max heat generation of the battery
The Max heat generated in which the current flowing 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 generates of 2.4006823936 Jouls.
Thus maximum heat produced by the battery is 2.406 J by mathematical calculation .
and soc at 208 seconds is 99.5% using simulink.