Project 5

Here 10 cells are connected in series and hence the voltage vill 72V and current will not change so current is 5.4Ah.As the battery model is identical parameters of only one battery is annalysed battery and other cells are assumed same. A bus selector select the signals from the 'm' port of the generic battery and ambient temperature is given by a constant block and controlled current source is used to take charge and discharge current from the battery pack.The input to the controlled current source is given by the charge/discharge logic implemented using matlab stateflow chart block where state changes with the SOC value.

Chart is intialised with discharging state and entry value of current I=2.5 Amp as described in the aging model and the state changes when SOC=0 (Battery fully discharged) and enter the charging state with current I=-2.5(negative for charging) and it will again changes state when SOC will become 100%(fully charged case), and this will be continue for the whole simulation time.

Here the simulation is run for 20 hours for the amnbient temperatures of 25 and 36 deg C

Here when the temperature is 25 C life cycle required for 20 hours is 5 and the cell temperature is around 36C

At temp 36

Here when the temperature is 36 C life cycle required for 20 hours is 5 and the cell temperature is around 49C

Also when the charging and discharging current increases the no of ageing cycles are also increased.

Conclusion

The age of the battery pack will effect by temperature, charging rate and discharging rate,lower value of the temperature, charging rate, discharging rate will results in reduced aging effect of battery pack and higher life cycle can achieved,but the temperature of the battery pack can effect the capacity of the battery independently, but its not permanent as the capacity of the battery recovered with the increase in temperature, although aging of the battery is irreversible.