Project 1 Mechanical design of battery pack
EV LIVE BATCH 21
QUES.1
STAGES OF BATTERY PACK DESIGN
BATTERY DESIGN PROCESS
Required Energy Capacity for the pack = 18kWh
Let us assume that the voltage of the battery pack = 400V
We know that P = VI, henc we can calculate the pack capacity as follows:
Pack Capacity = Energy Capacity / Pack Voltage
PAck Capacity = (18*10^3)/400 = 45mAh
#cells in series = Pack voltage/cell volatge = 400/3.3
= 121.1 = 122 cells(approx)
#cells in parallel = pack capacity/cell capacity = 45/2.5 = 18cells
Total number of cells in the battery pack = (#cell in series)*(#cells in parallel)
= 122*8 = 2196 cells
Weight of battery pack = (# total cells)*(cell weight)
Wg = (2196*76)/1000 = 166.89 = 167kg(approx)
Length of battery pack = (#cell in series)*(cell diameter)
L = 122*0.026 = 3.172 m
Width of battery pack = (#cell in parallel)*(cell diameter)
B = 18*0.026 = 0.468 m
Area of battery pack = L*B
A = 3.172*0.468 = 1.4845 sq. m
Volume of battery pack = A*(cell height)
V = 1.4845*0.065 = 0.0965 cubic m = 96.5 litres
Specific Energy density = (Energy capacity) / (Wg)
SED = (18*10^3)/167 = 107.78 Wh/kg
Volumetric Energy Density = (Energy capacity) / (V)
VED = (18*10^3)/96.5 = 186.53 Wh/L
Cost of Battery pack = (#total cells)*(cost of 1 cell)
= 2196*6,55 = $14,383.8 = Rs. 10,45,544.76