Project 2

Using MATLAB/simulink and  the drive cycle from the attached excel sheet, find-

1. The max heat generation of the battery 
2. 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

AIM:

Using MATLAB/simulink and  the drive cycle from the attached excel sheet, find-

1. The max heat generation of the battery 
2. 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- 

heat generated = joules heat + entropy heat

joules heat

from ohms law we know that 

V=IR

when the current flowing through a resistance, there is a heat dissipated inn the resistor this  heat dissipation is called joules heating.

joules heating is also known as ohmic heating

power

P=V*I=I^2*R

heat

H=∫P.dt with the limits of time 0 to t

H=I^2*R*t

where,

P=power 

V=voltage

I=current

R=resistance

H=heat

T=time

entropy heat

the heat generation due to entropy change inside a battery occurs when electro chemical reaction are performed. the entropy heat is reversible  heat resulting from change in open circuit voltage with respect to temperature at two electrodes.

batterry resistance = 0.5m ohm = 0.0005ohm.

1. a) Maximum heat generated = maximum joule heat + 2(maximum joule heat)

Imax = -0.896 A

tmax = 1.7 sec

Rint = 0.0005 ohm

maximum joule heat = (Imax)^2 * R * tmax

maximum joule heat = (-0.896)^2 * 0.0005 * 1.7 = 0.000682393J

Maximum heat generated = maximum joule heat + 2(maximum joule heat)

Maximum heat generated = 0.000682393J+2=2.000682393J

1. 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 

1. 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.
2. 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.

3. 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.
4. Signal Builder Block -To use any type of signal till 208 stop time.
5. Scope- to Display the output graph
6. Powergui -Set simulation type, simulation parameters, and preferences

 

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:

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)

Or

Z(t) = Z(0) - 1/Cn ∫ Ni*i(t) dt    with thw limits of 0 to t

where, Cn = Battery Nominal Capacity

           Z(t) = State of charge

            i(t) = Instantansous cell current

            t = time 

            Ni = coulomb efficiency

           Z(0) = initial state of charge

            + for discharging 

            - for charging

Due to Faid in the battery capacity over the time it shows error