Modeling of a Battery for Series and Parallel configuration

Aim: To build a battery pack with 3S4P configuration with generic battery block.

Model:

Explanation:

Here FTTP75 drive cycle is the reference speed to the system. Constant current of 15A and 2A current is supplied through a multiport switch. The current flow to the system is controlled through the current controller block. The connections for the cells in the pack are done in two types: 3S4P and 4S3P.

3S4P:

This type of connection gives:

Pack voltage = 9.66V

Pack capacity = 9.2Ah

4S3P:

This type of connection gives:

Pack voltage = 12.88V

Pack capacity = 6.9Ah

Reference Speed:

Results:

State of Charge for 3S4P:

The SOC at the beginning is 100% and reduces gradually to 72.5% at the end of drive cycle.

Voltage characteristics for 3S4P:

The Voltage is high during the start and voltage drop is more during the first 300seconds due to the increase in speed of the vehicle.

State of Charge for 4S3P:

Here the SOC reduces to 64% and the reduction is more as the capacity of the battery is reduced. The 4S3P connection provides more Voltage and hence less Ah capacity.

Voltage characteristics for 4S3P:

The voltage is high compared to 3S4P connection and reduction is more during the first 300 seconds due to increase in speed. This type of connection has more Voltage and less Ah capacity.

Conclusion:

If the cells in a pack are connected in series it provides more output voltage and if connected in parallel it provides more Ah Capacity.

As the refernce speed for the model is increased, the voltage drop is more.

Hence a battery pack should be designed considering the requirements.