Project 4

Aim - To calculate the capacity of the battery pack required and number of series- parallel connection. Steps to be followed while designing a battery pack .

Description/calculation :

Calculation of battery pack capacity:

No.of series parallel cell calculation:

Series connection:

motor voltage : 65v

cell nominal voltagev: 3.7v

no of series connection : motor voltage/ cell nomiinal voltage

no series connection : 65/3.7 = 17.56 or 18 .

Parallel connection :

motor current : 16.9A

cell current : 1.3A

no of parallel connection : 13

TOtal number of cell = 18*13

= 234

Step to be followed while designing a battery pack:

step:1 Cell after manufactured in industry undergoes various testing methods

• Aging test
• performance test
• safety test
• mechanical test . To its assure its performance

step:2 To achieve required voltage, current , and capacity cells are interconnected in various connections depending on the requirement and levels.

For low level : cells connected in series and then in parallel and form a battery pack .

for high level : cells are connected in parallel and then in series . This combination are use for high capacity

maximum times used combination is MpNs .

step 3: Cells are arranged in cell holder , case to form a structure .

step 4: These cells are connected by apporaches - spot welding, wire welding

Spot welding- A very short pulse of high current through two pieces of mtal to melt together and form a solid connection . Nickel strips bus bars are used for interconnections.vas shown in figure below

step 5: Thermal management conditions are taken care by cooling jackets , enclosure to increase the battery capacity and life .

step 6: BMS is provoided in battery systems,battery management system monitors,protects and allow the user to use the battery pack in a safe manner,BMs implemented in printed circuit board mounted with the batterypack.

It is the heart of othe battery it communicates with outer and inner components to fulldil the current and voltage requirement .

Apart from you should look into : specific energy density, c-rate, temp , saftey in different conditions and .

So these are steps to be followed while designing battery pack .