Project 2 Thermal modeling of battery pack
Aim: - To design a battery model to simulate the thermal effects and the life cycle performance according to the charge discharge cycle of the battery.
Study:
The simulation model of the battery is shown below:
In the model we have developed a battery pack of 10 cells series battery.
The model is simulated for different temperature given by the ambient temperature.
The battery model we have used is
The battery parameters are altered to get the desired simulation results.
- The nominal voltage is 7.2V and the ampere hour capacity is 5.4Ah.
- There is no change in the discharge characteristics.
- The temperature parameters are also kept at the default values.
- For the aging parameters, aging time is changed to a value of 20secs.The charging and the discharging is done at 1C charging as well as discharging rate.
The circuit is powered by the controlled current source, which is controlled by the square wave generator.
The Square wave generator has a Time period of 7200 sec and an amplitude of 5.4.
The square waveform is shown below:
The circuit is run for 3600*10 secs i.e. the battery undergoes 5 full charging and discharging cycles.
Now if we run the model for the ambient temperature of 20 deg Celsius, the output of the battery is shown below:
Here we can see the
- Voltage is limited to 8V for a single battery beyond which a battery may get damaged.
- The SOC is seen varying from 100% to 0% over the period of time.
- The Age of the battery is increasing after every cycle and is approximately 5 at the end of five complete charging and discharging cycles.
- The temperature of the battery pack is also limited to 48 deg Celsius.
For the Ambient temperature of 50 deg Celsius:
We can see with increase in temperature the voltage current and SOC is not very much effected but the age of the cells are increasing with a much faster rate. The age at the end of the 5 lifecycle is around 7.
The temperature of the cell is also increased to a value of 80 deg Celsius.