Project 2
a.) The max heat generation of the battery:
There are 2 componeents for heat generation in the battery pack:
-> Joules heat
-> Entropy heat
Heat generated = Joules Heat + Entropy Heat
Joules Heat :
froms ohms law we know that
V = IR
when a current flowing through a resistance, there is a heat dissipated in the resistor. This heat dissipation is called Joule heating. Joule heating is also known as ohmic heating.
Power,
P = V*I = I*I*R = I^2*R
Heat,
H = ∫P.dt with the limits of time 0 to t
H = I^2*R*t
Joule heat,
H = I^2*R*t
where. p = Power
V = Voltage
I = Current
R = Resistance
H = Heat
t = Time
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
Maximun current = -0.896 A
Max current time = 1.7 sec
Entropic factor = 2
Total heat generation = Jouleheat + Entropy heat
The maximum heat generation in the battery pack
Max heat generation = Max Joule Heat + Entropy factor
Max Joule Heat = I^2 *R*t
Max Joule Heat = -0.8962⋅0.0005⋅1.7">−0.8962⋅0.0005⋅1.7-0.8962⋅0.0005⋅1.7
Max Joule Heat = 0.0006823936J">0.0006823936J0.0006823936� `
Max heat generation = 0.0006823936 + 2 = 2.0006823936 Joules
The Max heat generation is 2.0006823936 Joules.
b.) The SOC of the battery at 2*104 second of the battery operation:
SOC = State of Charge indicates how much of energy is left to be used
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 editor Block -To use any type of signal till 208 sec stop time.
- Scope- to Display the output graph
- Powergui -Set simulation type, simulation parameters, and preferences
The simulink model for finding the SOC at 208 sec is as below:
Inside the signal editor block(.mat file is attached) we have set the signal as available in the attached excel sheet(Current profile.xlsx) , the dataset in this excel file has been imported into the signal editor.
Battery configured as shown below:
Controlled current source configured as below:
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 as shown below -