Generic Battery Model's Characteristics using UDDS Cycle.
Simulating the generic battery model using the UDDS data and studying the Battery characteristics using plot of SOC, Voltage and current with the time.
The figure shown is the Simulink block diagram to study the generic battery behaviour.
The generic battery has the following default characteristics:
Nominal Voltage = 7.2V
Rated Capacity=5.4V
Full Charged Voltage= 8.38 V
Initial SOC=100%
Following is the part of UDDS cycle used in the model.
The following plot is of SOC (State of Charge) vs Time in yellow colour; Voltage vs Time and Current vs Time.
The time period taken is 1400 sec.
The following graph is plotted Current VS Time
This graphs shows the current variation from the energy source i.e. Battery which varies in accordance with the UDDS data. The rise in current shows the energy required to accelerate to increase the speed. This utilization of the current from the battery discharges the energy source and hence the SOC reduces. When regenerative brakes are applied, negative current flows and battery recharges hence the SOC increases.
This graph shows the reduction in SOC of the battery. Initial SOC was 100% and when the UDDS cycle ends, the final SOC reaches around 96%. The region between 200-300 sec shows steep decrease in SOC because of high current flow rate from the battery. The high flow can be seen in the Current VS Time graph.
After 300sec, The SOC increases because the battery undergoes charging during regenerative braking. The entire SOC VS Time graph shows the constant reduction and increment in of the state of charge as the current supply from the battery varies.
The initial Voltage is around 8.4V. after the UDDS data is applied, the final voltage drops to 7.85 V.
The Volatge VS Time graph shows the expected battery behaviour. Initially we obtain a steep fall in the voltage which gets constant after reaching a certain State of charge. The Variation in the voltage graph is in accordance with the charging and discharging occurring due to constant acceleration and regenerative braking.
This Graph is done for additional understanding of Current with the its SOC and voltage of the battery.
When Current is increases beyond the maximum (Compared with the UDDS data), SOC decreases steeply. (Time = 200sec & 500sec)
Also when constant Negative current is passed, SOC increases and battery gets faster recharged. (Time = 300sec)
We can also see a increasement in the voltage when constatly high negative current is allowed to flow through the battery.