Project 2 Thermal modeling of battery pack
The Model for simulation is taken from the MATLAB base model
This simulate a battery pack consisting of multiple series connected cells in an efficient manner.It is also shows how a fault can be introduced inyo one of the cells to see the impact on battery performance and cell temperatures.For efficiency,identical series-connected are not jsut simply modeled by connecting cell models in series.Instead a single cell is used,and the terminal voltage scaled up by the number of cells.The fault is represented by changing the parameters for the cell 10 fault subsystem,reducing both capacity and open circuit voltage,and increasing the resistance values.
Simulink model:
The blocks used in the model include
1.Temperature sensor
2.Temperature source
- Convective heat transfer
The rate of heat transfer is proportional to the temperature difference, heat transfer coefficient and surface area in contact with the fluid
- Conductive heat transfer
- Battery pack
Battery subsystem:
This consists of thermal model and lithium cell 1RC block which calculates temperature and thermal effect of the cell and overall calculation of the battery pack.
The ps gain block multiplies the input physical signal by a constant. Other blocks used are voltage sensor and current voltage sensor.
Lithium cell1 RC
It consists of capacitor value table which depends upon the external physical signal input, SOC and T.
Capacitor value varies with time and hence the equation i=C*DV/dt.
Resistance value depends on the external physical signal inputs, SOC and T.
Voltage value (Em) implements the cell’s main branch voltage source and determines values for capacity and SOC.
- Gain block
7.integrator block
8.current sensor
9.AC current source
Output:
SOC:
The ambient temperature provided by the source is 293.15k
The battery pack cell01-04 reaches a maximum temperature of 336k. The faulty cell 05 reaches maximum temperature of 325k. The cell pack 06-10 reaches maximum temperature of 324k
The model which have input from UDDS drive cycle
UDDS drive cycle input waveform
SOC :
CONCLUSION:
The ambient temperature provided by the temperature source is 293.15k
The SOC of the model starts from 0 and reaches 0.9 in1400 seconds.