Battery characteristics using drive cycle

AIM:

To simulate the charge discharge characteristics of a generic battery model during an UDDS drive cycle in MATLAB.

EXPLANATION:

The battery that is in consideration is the LIR18650 2600mAh cell.The specification of the cell is as follows

Nominal Capacity:2600mAh

Typical Capacity:2550mAh

Minimum Capacity:2500mAh

Nominal Voltage:3.7V

Internal Resistance:70m`Omega`

Cut Off Voltage:3V

Maximum Charge Voltage:4.25V

Standard Charge Current:0.52A

Rapid Charge Current:1.3A

Standard Discharge Current:0.52A

Rapid Discharge Current:1.3A

When charging the temperature of the battery must be in the range of 0 to 45 degrees and while discharging the temperature must in the range of -20 to 60 degrees.

When the battery is to be stored for a period of a month the temperature can be in the range of -5 to 35 degrees but if it is to be stored for 6 months then the temperature should be in the range of 0 to 35 degrees.

The Simulink model associated with the analysis is as follows

The drive cycle data is imported using a signal builder. Variables of time and current are created from the original data file and the required signal is created from it. The output of the signal builder is current which is given as input to the controlled current source. The output of the controlled current source is given as input to the generic battery model. The output port of the battery model has multiple signals which can be given to a bus selector through which the individual signals can be extracted and plotted.

The parameters of the battery are modelled as follows

The nominal voltage is set at 3.7V and the rated capacity of the battery is set at 2.6Ah.The battery is assumed to be fully charged initially.

The option to calculate the values from the nominal parameters is checked against and the discharge currents are entered.The discharge characteristics of the battery against time is as follows

The discharge characteristics of the battery against capacity is as follows

After the battery has been configured the driving cycle has to be generated using the signal builder block.The UDDS driving cycle data can be imported in the signal builder.

The current over the entire drive cycle is as follows

The voltage over the entire drive cycle is as follows

The SoC of the battery over the entire drive cycle is as follows

RESULT:

The battery discharge characteristics of a generic battery is simulated using the UDDS drive cycle as input in MATLAB