Project 2

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

a. The max heat generation of the battery :-

Given :-

Battery resistance = 0.5 mohm

= 0.0005ohm

Entropic factor = 2

To Find :-

Maximum heat generation of the battery pack

Step :1

We , know that

Heat Generation = Joule's heat + Entropic Heat

from ohm's law

V = I*R

When a current flowing throgh resister the heat dessipation is takes place , this heat dessipation is known as joule's heat. It also known as ohmic heating.

Power (P) = V*I = `I^2*R`

Heat (H) = `int 0 to t Pdt`

H = `I^2*R*T`

Where ,

H = Heat

I = current

R = Resistance

T = Time

P = Power

Entropic 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.

Step :2 To Calculate Maximum generation of Heat ,

Imax = -0.896

Tmax = 0.7 Sec

Battery internal resistance (R) = 0.0005 ohm

Maximum Joule's Heat = `(Imax)^2*R*Tmax`

= `(-0.896)^2*0.0005*0.7`

= 0.000682393 J

Maximum generation of Heat = Maximum Joule's heat + 2* Maximum Joule's Heat

= 0.000682393 + 2 * 0.000682393

= 2.000682393J

`therefore` The maximum heat generation is 2.000682393 J

b. The SOC of the battery at 2 *104second of the battery operation :-

SOC ( State of charge ) it is defined as the how energy is usable for a certain application

SOC = Q / Qmax

where ,

Q = Available capacity

Q max= overall capacity

Step :1 For simulation model the blocks are used ,

1. Generic Battery - Impliments a generic battery model for most popular battery types. Temperature & aging (due to cycling) effects can be specified for lithium ion battery.

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.

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.

4. Signal Builder Block - To use any type of signal till 208 stop time.

In this case we used a given drive cycle of excel sheet ,

5. scope - To plot the output graph.

6. Powergui - set simulation type , simulation parameters & preferences.

Step :2 Simulink model ,

Step :3 Output of SOC% using scope ,

• From above plot it is observed that the SOC of battery pack is 33 at 120 Seconds.

Conclusion :-

• In this project we have calculated the generation of maximum heat is 2.000682393 J.
• Also we have simulated the battery SOC for the given drive cycle.
• At 120 second, the battery SOC is around 33%.