Project 2 Thermal modeling of battery pack

Question :- For a 10 cell series lithium ion battery model, simulate the thermal effects and compare life cycle performance at various temperatures, charge & discharge rates using MATLAB.

Program Blocks :-

Battery Table Based:-

This is battery table based block with instrumented and thermal port to get SOC output and to give temperature input to the system. Every value is taken as default.

Temperature Source :-

This block is used to give or take heat to the system to increase or decrease temperature.

Convective Heat Transfer :-

It is used to transfer medium for heat. It can pass heat and increase temperature of system by convection.

Temperature Sensor :-

It is used to sense temperature from the system. And give output which we can plot or display.

Thermal Reference :-

This block is used to give reference to the thermal input source. By which it can compare and give heat to the system.

PS Simulink Converter :-

It is used to connect physical system to the simulink.

Scope :-

It is used to plot output in graph.

Current sensor :-

It is used to sense current flow and to get output.

Controlled Current Source :-

It is used to charge or discharge connected system. Which can be controlled by input value.

Simulink PS Converter :-

It is used to connect simulink block to the physical system.

Constant :-

It is used to give constant value as input to the system.

Solver Configuration :-

It is used to give mathematical reference to the equation which is computed during analysis.

Electric Reference :-

It is used to give refence to the system to compute all electrical circuit.

Goto :-

It is used to transfer value to one place to other by calling another block without any physical connection and wherever we need.

From :-

It is used to call the value which is transferring by using goto block and wherever we need.

Program :-

• First of all all 10 batteries are connected in series.
• After that to charge or discharge battery connected controlled current source. In that constant value is give to charge or discharge to the current source.
• Then to measure current flow current sensor is added in circuit and its output values are connected in scope by goto and from block.
• Now all battery thermal input port is connected with thermal source to give heat addition or removal from the system through convection block.
• After than there is need to check temperature of system so added temperature sensor with thermal referance. Its output is connected to scope by goto and from block.
• To get SOC data, SOC output port of battery is connected to the scope by using goto and from block.
• System has mathematical equation and also electrical circuit so need function solver configuration and electrical reference.
• Like this system is created.

Working :-

• As system is connected, when battery is discharge with known value of current, thermal source is changing temprature and heat the batteries.
• A temprature of battery increase there is aging and other losses are increasing so SOC is vary at different temprature input which we can plot.

Outputs :-

1. At 4A current discharge with different temprature at 1500 second :-

Comparison :-

Temperature	SOC
300	0.593
320	0.584
340	0.579

• As clear from the graph is that at constant discharge ampere SOC is decreasing as temperature of battery increase.
• Temperature is increase simultaneously in all three analysis and as temperature increase in different analysis SOC decreasing chart slop is increase.
• So, battery drain faster.

2. At same temperature with different charging rate at 950 second :-

Comparison :-

Charging Rate	SOC
3	0.2
4	0.267
5	0.334

• At constant temperature, while comparing SOC of battery at different charging rate, it shows that as usual SOC increase which was measured at 950 second for all three analysis.

3. At same temperature with different discharging rate at 950 second :-

Comparison :-

Discharge Rate	SOC
3	0.837
4	0.77
5	0.703

• While discharging at same temprature, as shown, SOC is decrease with increase discharge rate.

Conclusion :-

• From above analysis, it is clear that SOC is decrease higher rate when discharge current and temperature of battery is increased.
• So, battery performance is decrease and aging process increasing. Finally battery drain rapidly.