Project 4

A battery pack is a set of any number of (preferably) identical batteries or individual battery cells. They may be configured in a series, parallel or a mixture of both to deliver the desired voltage, capacity, or power density. The term battery pack is often used in reference to radio-controlled hobby toys and battery electric vehicles

First we have to Do calculation part for the find the battery pack capacity for this

Given Data,

Vehicle Weight=300kg

Motor Rating=1200wh.65V

Range=225Km

Max Speed=50 kmph

First we have to calcualte Motor Current

Power = V*I

1200 = 65*I

I = 1200/65

I = 18.46 A

Current withdrawn By Motor 18.46 Amp

Assure Current Loss 1-10%

After loss new motor current

18.46*1.05=19.38 amp

Now Calculate the Power requried at max speed

At 60kmph power= Voltage*Current

Power= 65*19.38

power=1260w

Now calculate Travel Foctor

Travel Factor= Total Range/ Total Speed

Travel Factor = 225/60

Travel Factor= 3.75

To calculate Power based on Travel Factor

Power requried = Power*Travel Factor

power requried=1260*3.75= 4725 = 4.7 kw

Now calculate Battery pack capacity based of efficiency

Battery pack efficiency 85-95%

we Consider 85%

Required Battery Pack Capacity= 47/0.85 = 5.52 kw

To Calculate Battery pack efficiency based on motor efficieny

Total Battery Pack capacity = 5.52/0.85 = 6.49 kwh

Now we have to find how many connections comes in series and parallel

Series Connection

Motor Voltage 65 V

Cell Volatge 3.7v

No of series cells. 65/3.7 = 18

18 cells in series

Parallel Connection

Motor Current 19.38 A

Cell current 2.8 A

No of parallel cells 19.35/2.8 = 7nos.

7 Cells in parallel

We have Calculate the capacity of the battery pack that is 6.49 kwh and also we find the number of series-parallel connections that is series connections=18 cells in series,parallel connections=7 Cells in parallel and mention the steps for how to built a battery pack