Project 1

Design a battery pack for a car roughly 150 Kw with 120 V. Use 3500 mAh 3.6V nominal NMC chemistry cell.

Design the battery pack configuration.

Given datas

Power =150Kw

Voltage=120V

Nominal capacity=3500Ah

Nominal Voltage=3.6V

So First we need to find no of cells in Series

No of cells in series= rated voltage/ nominal voltage

=120/3.6

=33.33

case 1

By rounding off to 33.33 to 33

Nominal battery voltage=nominal cell voltage x no of cells

=3.6*33=118.8 V

Maximum battery voltage= maximum cell voltage x No of cells

=4.2*33=138.6 V

Minimum battery voltage=minimum cell voltage x No of cells

=2.7*33=89.1 V

Case 2

By rounding off to 33.33 to 34

Nominal battery voltage=nominal cell voltage x no of cells

=3.6*34=122.4 V

Maximum battery voltage= maximum cell voltage x No of cells

=4.2*34=142.8 V

Minimum battery voltage=minimum cell voltage x No of cells

=2.7*34=91.8 V

it is always better to have more coltage so we choose case 2 34 cell in series

we need to find no of cells in parallel

power=150kw

voltage =120v

I=150*1000/120=1250 A

No of cells in parallel=Total current / Cell capacity

=1250/3.5=357.142

357.142 rounded to 358

so the battery pack will be 34s358p

Draw the BMS topology for this battery pack.

we will choose master slave topology