Project 2 Thermal modeling of battery pack
Aim:-
To Model and simulate a 10 cell series lithium ion battery pack and analyse its thermal effect and to compare life cycle performance at various temperatures, Charge and Discharge rate using Simulink.
Description:-
Lithium Ion Battery:-
Lithium ion battery is an rechargable battery type which are commonly used for portable electronics and in EV and now its applications are increasing such as aerospace,etc.
Based on the type of lithium ion battery performance, Cost, Safety and Chemistry varies. Based on the application the lithium ion battery types are choosen.
Here reasearches are made to increase lifetime, energy density, Improving Safety, Reducing Cost and Charging Speed and to produce an non-flammable electrolyte are taking place.
Simulink Model:-
10 Lithium Ion battery cells are connected in the series combination containing 3 pack where the first pack containing 4 cells and second pack containing 1 cell and the third pack containing 5 cells all connected in series.
The heat transfer is observed between the packs by using conduction and convection block and temperature graphs are observed by using the T subsystem connected between each pack.
The ambient temperature source connected to thermal sensors used for displaying the temperature. The battery pack is connected to AC source to give cyclic charge and discharge current to battery.
The SOC of battery is calculated by using the current sensor and SOC calculations are made.
Cell Subsystem:-
The cell subsystem consist of a thermal model and lithium cell 1RC block which is used to calculate the temperature and thermal effect on the cell.
Thermal Model Subsystem:-
It contains a thermal reference, Controlled heat flow source, Thermal mass and temperature sensor.
Parameters:-
Battery Configuration:-
The values are declared by using model workspace as shown below
Temperature Source:-
The temperature that is the ambient temperature is set to 293.1 intially and is given in parameters as shown below
Parameters:-
Thermal Elements:-
Conduction and convections are thermal heat transfer blocks used and its parameters are as follows
Conductive heat transfer parameter:-
Electrical Source:-
It is an ideal current source block that maintains sinusoidal wave here we set peak amplitude to 50 and phase shift is set to zero and frequency of 1/600 hz is set.
Parameter:-
Current Sensor:-
Current sensor is used to convert current measured in electrical signal to physical signal which is proportional to the current.
SOC Calculation:-
The SOC calculation is made using gain block, integrator and add block and displayed using scope.
Result:-
Test 1:-
By setting,
Ambient Temperature to 293.1
Cell Temperature:-
Intially the temperature is at 293.1 for all the cell, Since cell 5 is at fault there is rise and fall of temperature is high compared to the other packs.
The highest temperature reached by Cell 1-4 is 326 K
The highest temperature reached by Cell 5 is 337 K
The highest temperature reached by Cell 6-10 is 325 K
SOC:-
The SOC Maximum state at intial stage is 9.542 whereas at 7000 sec that is after 11 cycles of charging and discharging the maximum SOC is reduced to 9.539.
Charge and Discharge profile:-
Test 2:-
By setting,
Ambient Temperature to 299 K.
Cell Temperature:-
Intially the temperature is at 293 for all the cell, Since cell 5 is at fault there is rise and fall of temperature is high compared to the other packs.
The highest temperature reached by Cell 1-4 is 332 K
The highest temperature reached by Cell 5 is 343 K
The highest temperature reached by Cell 6-10 is 331 K
SOC:-
The SOC Maximum state at intial stage is 9.539 whereas at 7000 sec that is after 11 cycles of charging and discharging the maximum SOC is reduced to 9.535.
Charge and Discharge profile:-
Test 3:-
By setting,
Ambient Temperature to 310 K.
Cell Temperature:-
Intially the temperature is at 293 for all the cell, Since cell 5 is at fault there is rise and fall of temperature is high compared to the other packs.
The highest temperature reached by Cell 1-4 is 343 K
The highest temperature reached by Cell 5 is 354 K
The highest temperature reached by Cell 6-10 is 342 K
SOC:-
The SOC Maximum state at intial stage is 9.541 whereas at 6000 sec that is after 11 cycles of charging and discharging the maximum SOC is reduced to 9.540.
Charge and Discharge profile:-
Test 4:-
By setting,
Ambient Temperature to 350 K.
Cell Temperature:-
Intially the temperature is at 293 for all the cell, Since cell 5 is at fault there is rise and fall of temperature is high compared to the other packs.
The highest temperature reached by Cell 1-4 is 382 K
The highest temperature reached by Cell 5 is 393 K
The highest temperature reached by Cell 6-10 is 381 K
SOC:-
The SOC Maximum state at intial stage is 9.539 whereas at 7000 sec that is after 11 cycles of charging and discharging the maximum SOC is reduced to 9.538.
Charge and Discharge profile:-
Conclusion:-
With difference in temperature we can observe the change in cyclic charge and discharge rate is absorbed and the cell temperature and in SOC there is no change with change in temperature the as it stays almost the same.