Project 5

For a 10 cell series, calculate the voltage, current and SOC. Also simulate the aging and thermal effects at different charge and discharge rates. Comment on the battery pack’s capacity.

Ans-

Simulink Model-

The above fig shows the 10 cell series lithium ion battery model.These are all battery cells connected in series.

For this we enables the temperature effect option of cell for observing, estimating the temperature effect & signal effects.

So in this model we estimate the SOC of the battery pack, temperature of battery pack i.e. ambient temperature, battery pack current by using Scope

Ambient temperature & OC of the cell is similar to other cells.The battery pack voltage is calculated by using a voltage sensor block is connected across the battery pack terminals, first cell positive terminal connected to the positive terminal of voltage measurement block and last cell negative terminal connected to negative terminal of voltage sensor block.

current measurment is connected in series and SOC.Bus selector is connected to last battery to give valuea to the scop.

Case 1-

10 cells connected in series a one single battery voltage is 7.2v current 5.4A and the charging and discharging time of battery pack is default value [2.3478, 6] and [2.3478, 10]. the ambiant temprature of the battery is 25 and SOC rate is 100per for Soc build a sepret subsystem shown as below image.

Below image is shows the parameters of the cell which are concider while simulating the model

Discharge parameters-

Temperature parameters

Aging parameters

For above parameters we get below scope, in this battery is 100% charge already and then cycle is start and we get a below scope as we can see in scope SOC is going down from 100% to 0% and also we can see the thermal effect of battery pack

Case 2-

In thise case the battery voltage and current is same 7.2V and 5.4A but charging and
discharging current is change charge current is 5.4 and Discharge current is 3 and ambient
tempreture of the battery is set to be 45 and other blocks parameters is same SOC is
100persent as shown on below image.

For above parameters we get below scope, in this battery is 100% charge already and then cycle is start and we get a below scope as we can see in scope SOC is going down from 100% to 0% and also we can see the thermal effect of battery pack when aging and temperature value are changed.

Conclusion:
From above two case we can conclude that,
When we increase the ambient temperature then cell temprerature increased also
this ambient temperature adverse effect reflects on the age of the battery pack and vice
versa.
Similarly when we decrease C rate then shows the favourable and unfavourable effects on
the age, SOC, temperature and voltage of the battery pack.