Thermal modeling of battery pack (10 batteries)
OBJECTIVE-1:
To simulate the thermal effects for a 10 cell series lithium ion battery model.
Working:
The above model shows the simulation of the thermal effect of 10 cells connected series in the circuit. The cells used here are each 50Ah with the total capacity of 500Ah battery is formed by connecting 10 batteries in series. The battery temperature port is connected to the temperature sensor so the temperature of each cell battery is sensed and viewed in the scope and parallely the temperature port is connected to the out ambient temperature. The state of charge of the battery pack is counted by the Coulomb method ,that is done by the integration of charge after counting is calculated with the past value and displayed in the scope. The draining current from the battery pack is controlled by the controlled current source, that is controlled by the constant block.
Result:
Thus the thermal effects for a 10 cell series lithium ion battery model is simulated and the result is plotted above.
The batteries have the initial temperatures the same but due to the mismatch in the soc and discharge rate of each battery the different heat generation can be observed in graph.
OBJECTIVE-2:
To compare performance at various temperatures, charge & discharge rates using MATLAB.
To analyse the charge and discharge rate with temperature Let’s take the example of 3 cases.
Case-1: -1discharge rate
The -1 discharge rate is very low discharge rate to the 500Ah battery so there is no major decrease in the SOC in 1hour. Because of low discharge the heat generation is very low (almost 0).The battery keeps the same temperature tille 1hour.
Case-2: -50discharge rate
The -50 discharge rate is little higher discharge rate compared to the old discharge rate, so there is decrease in the SOC in 1hour, the SOC decreases from 100% to 90%. Because of this discharge the heat generation is high comparing to the old case. The battery keeps rising the temperature gradually and finally ends in 500kelvin.
Case-3: -100discharge rate
The -100 discharge rate is a higher discharge rate of the 500Ah battery so there is a decrease in the SOC, the SOC decreases from 100% to 81%. Because of this discharge the heat generation is high compared to the old case. The battery temperature rises suddenly and reaches the max value and gets saturated over the range of 500 kelvin.
All the results are taken for the discharge rate similarly the results can also be studied for the different charge rate.
Simulink model link:
https://drive.google.com/file/d/1aBJlG7eiWtGAN3-Alff4FCU5q-daoPIy/view?usp=sharing