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.

AIM: 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.

Battery Model with Charging, Discharging and temperature effect:-

In this project we 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.

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,

SOC CHART

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.

The input to the controlled current source is given by the charge/discharge logic implemented in matlab chart where I create a charging and discharging state which changes with the SOC value.

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 (Battery fully discharged) and enter the Charging state with current I=-2.3478(negative for charging) and it will again changes state when SOC will become 100%(fully charged case), and this will be continue for the whole simulation time.

plotting:

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.