Project 2 Thermal modeling of battery pack
For better results I have used matlab example 20 series cell with fault and modified it.
The thermal block are same as we used in previous challenges .
1]CONVECTIVE HEAT TRANSFER : this block is used cause in real life there are no such heaters used to heat the battery except working below 0DC ,
so the heating here takes place due to environment and the battery cells themselfs so no physical heat transfer take place.
2]CONDUCTIVE HEAT TRANSFER : this block is placed between the cells because we know in a battery pack cells are placed closed to each other and there is a physhical contact in between them and hence physical heat transfer takes place between them so CONDUCTIVE HEAT TRANSFER block is used
RATE TRANSITION : this block is used to handle the transfer rates so the cyclic curve is not disturbed
GAIN: gain block are used to lower the curves or we can say bring in limits , without gain block parameters the values of wave will vary betwwen much high difference
DISCRETE-TIME INTEGRATER:
this intergrates the current values over period of time and as the current is withdrawn from the battery this always provides negative values which are further used for estimation of SOC.
Following is subsystem is used for calculation of Soc
1]We know values of SOC range is 1-0 i.e 100%-0% so a constant block is used with value of and ouput of intregretor is added to it .
2]Value is added to it because output is negative and hence subtracting will result in adding of integrater ouput to the constant value 1 which will not give us the required values of SOC .
3]To display the values of the SOC the scope block is used .
The entire objective of project is to see the effect of temperature on the cell
which in our case is cell5
to sense this temperatures at different cells temperature sensors are used and scope is added to the sensor so that we can study the values.
RESULTS:
1]We can see that the faulty cell5 has a immense rise in its temperature and fluctuation cause of its interfaults.
2]This also affects the SOC of cell
3]2nd figures confirms the same .
4]We can see that the faulty cell at first has the less SOC due to internal loss and hence charges less and at the cycles it rapidly discharges and is the only cell on tha pack that reaches the lowest SOC values
5]To confirm the same temperature nature scope plot is aslo shown.
SOC of entire battery pack:
CONCLUSION : To avoid such cases the only solution is proper BATTERY MANAGEMENT SYSTEM .