Project 2

Objective:

• 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
• Consider the battery resistance is 0.5 mOhm, delta time is 0.1 and entropic factor is 2

Battery resistance2 milli ohm

Theory:

• 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
• Consider the battery resistance is 0.5 mOhm, delta time is 0.1 and entropic factor is 2.

Solution:

Heat generated = Joule heat + Entropy heat

Joule heat

• Joule heating is the physical effect that increases the internal energy and collision of electrons in a circuit carrying current that results in the generation of heat energy.
• The Joule’s heating formula is given by Q=I^2Rt.

• According to Joule’s heating formula, the heat energy generated is proportional to the time when the electric current and electrical resistance are constant.

The Joule’s heating formula is given by:

Q = I^² Rt

Q is the amount of heat generated expressed in Joules.

I is the electric current in Ampere.

R is the resistance offered by the circuit to the electric current flow in Ohms.

t is the time the current is allowed to flow in the circuit expressed in seconds.

Consider an example of Joule heating, where 5 A of current is flowing through an electric wire of resistance 20 Ω for 10 s. The heat energy generated in Joules can be calculated using Joule's heating formula:

Q = 5^{^2} x 20 x 10 = 5 kJ

Given Data,

Battery resistance=0.5 mOhm

Maximum current= -0.896 ;

Time at maximum DoD, t= 120sec

entropic heat = factor 2 = 2(Joule heat)

Maximum power loss =I^2 *R = (-0.896)^2 *0.5 = 0.4 watt

Joule heat = I^2 *R*t = (-0.896)^2 *0.5* 120sec = 48.16896J

Max heat generated = joule heat + entropic heat

= joule heat + 2(Joule heat)

= 48.16896+2 (48.16896)

= 48.16896+96.33792

= 144.50688 J

• The max heat generation of the battery = 144.50688 J