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.

A)AIM:The Objective of this project to make a Simulation for a 10 cell series,we have to do calculations depending some parameters in Battery model ,and also that can simulate the Aging effect of battery and observe/comment on Aging of battery in different temperature, charging/discharging rates of the Battery pack.

Explanation:

Battery Model with Charging, Discharging and temperature effect:-

Here,In this project we have to make a battery model which can allow to simulate Battery charge/discharge characteristics along with aging and temperature effect of 10 series connected cell. For this purpose we use Generic battery model in simulink environment and simulate aging and temperature effect. take a look at this model first.

after that Next step is Here we connect 10 series Battery having 7.2V nominal voltage and 5.4Ah capacity, this is the inbuit data of the battery pack that will open when you first introduce the block, and we're not changing the model except for Battery response time(2) and Aging model sampling time(10s) but we adjust all other parameters of our model to observe aging efffect of battery in different ambient temperature, Charging/Discharging rate. The parameters of Battery pack is given below,

10 series Battery model is identical and together they make 7.2*10 = 72V Battery pack model with 5.4Ah capacity. As the battery model is identical we only observe parameters of first battery and assume It will be same for all other cells. So we take a Bus selector to select the signals from the 'm' port of the generic battery and I give Ambient temperature by a constant block and I also measure The voltage and current of the battery pack by voltage and current measurement block. and I use a controlled current source to take charge and discharge current from the battery pack.

Here we can see the chart intialise with Discharging state and entry value of current I=2.3478 Amp as discribed in the aging model and the state changes when SOC=0 and enter the Charging state with current I=-2.3478 and it will again changes state when SOC will become 100%, and this will be continue for the whole simulation time.

Now we simulate the model for 20 hour with and check the results that are shown below

total voltage and current of the battery pack. the voltage is 10 times of the cell voltage and current is same as the cell current due to series connection and we can see here the cell starts discharging first then achieve its lowerr cutoff voltage and start charging and it charges to the maximum voltages and starts discharging again

Here we can see the charge and Dischrge characteristics are same as previous by cell temperature rises to around and age of the cell is increased to around 1.6(grater than 1) for the 1 life cycle, and Battery capacity is also reduce more compare to previous case.

Even though the charging and discharging rates are same the cell temperature will affect the age of the battery and battery can derate at faster rate.

Now we just take all the same value of all other parameter but we change the ambient temperature to and now take a look at the results once again.

Temperature Case:- Now we just take all the same value of all other parameter but we change the ambient temperature to 45and now take a look at the results once again.

Discharge rate Case:- Now take the temperature as 25but this time we increase the Discharge current to 10A by keeping all other parameter same now observe the graphs....

Charging rate Case:- Now we take all other parameters as first case except for charging current, that we changed to 3 Amps.

here we can see the discharging current is same as previous and charging current is 5A so the Battery charges in less time while discharging of battery pack takes longer time but in meanwhile the cell completed almost 6 life cycles in 20 hous and also ripple in temperature increases due to high charging current and low discharging current.

Thermal Effect on Battery:- As we know the Ambient temperature will effect the Battery performance so now we try to analyse how an Lower Ambient Temperature will reduce the battery performance. To simulate this effect we take same procedure that we follow in this project and take the same value as first case as charging current=discharging current=2.3478A. But I change the Ambient temperature to and I run the model to get the simulation results

Conclusion:-

We can conclude that the Age of the Battery pack will effect by Temperature, Charging rate and Discharging rate. Lower value of the temperature, charging rate, discharging rate will results in reduced aging effect of battery pack and Higher life cycle can achieved