[philso]

Devyash

You should carefully consider the size of the individual batteries and the number that you have to connect in series/parallel to get the energy you want.

The smaller the batteries, the more "strings" you will have and the more connection points you will have. Connection points are the most common failure point in electrical/electronic systems. I have only seen strings of batteries connected in parallel at the two ends of the strings. This allows the use of Battery Management Systems to be used to monitor each cell. I have never seen the intermediate points connected in parallel since it would prevent the monitoring of individual cells.

Since you are using these in a vehicle, you will be concerned with system weight and volume. A pack made up of smaller batteries might weigh more and take more space than one made up of larger batteries. The shell of the battery may constitute a larger percentage of it's weight than in a larger battery. You will have to study the detailed specifications carefully and estimate your overall weight and size. A BMS for small batteries is about the same size and weight as the BMS for a larger battery so a pack made up of small cells will have more weight and volume taken up with the BMS.

If you are using high discharge rates, the smaller batteries will have more surface area per unit of energy storage, making it easier to keep the battery pack within it's specified operating temperature limits.

The flat discharge curve followed by a rapid voltage drop is a good reason to use a BMS to prevent you from damaging the battery pack.