Project 2

Aim of the Project:

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:

The max heat generation of the battery :-

The maximum current in the drive cycle is -0.896 at 1.7 minutes(102 seconds)

Battery resistance:0.5mOhm

maximum heat generated =I^2Rt=(-0.896^2)*0.5*102=40.94 milli Joule

The total heat generated =Joule heat+Entropic heat

=40.94 milli Jule+2(40.94 milli Jule)

=122.82 milli joules.

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

Heat generation in Li-ion batteries:

In a LIB, the behavior of current collectors, separator, and electrodes is different in heat generation. In current collectors heat is generated due to the ohmic resistance of passing electrons. In the separator, heat is generated due to the ohmic resistance of passing lithium ions through electrolyte.

Impedances existing in structural materials of lithium-ion batteries and in electric double layer cause overvoltage during charge/discharge. In addition, currents flowing in resistive components of these impedances produce Joule heat to be released inside the battery. Therefore, generally, if a battery's internal equivalent circuit can be identified with regard to these impedances, then heat generation caused by overvoltage can be estimated as a total Joule heat produced by all resistances in the circuit.

Heat generation:

Heat Generation Calculation:

There are two heat sources for battery heat generation.

• Joule heat
• Entropy heat

Heat generated = Joule heat + Entropy heat

In this project Entropy heat is 2 x Jule heat

Average heat generated = average joule heat + 2(average joule heat)

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

Result and 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 122.82 milli joules.