Battery Management System

Project Title

Battery Management System

Project Area of Specialization Internet of ThingsProject Summary

With the advancement in technology and increased
need for mobility, the utilization of rechargeable batteries and
portable power storage has increased.This fact has only added to the need of a battery management system which can manage the charging and discharging of individual batteries within a battery pack in order to protect them from damage caused by over-charging or deep discharging due to unbalanced charging.This paper presents Battery management system which controls the charging/discharging and avoid the batteries to get unbalanced and increase the life and efficiency of the batteries.This has been
done by coulomb counting combined with open circuit voltage method for determining percentages of individual batteries in a battery pack.We do coulomb counting using a current sensor working on Hall Effect.We have achieved our goal by designing an algorithm that measures SOC percentages continuously and in case difference occur in percentages equalization circuit starts working to balance them with the help of Arduino and then proved them with results displayed in the form of percentages
on the TFT panel.

Project Objectives

This project, inspired by the researches made on these methods, proposes a combined coulomb counting and open circuit voltage method for determining SOC of individual batteries in a battery pack and then applying equalization of SOC with the help of a relay circuitry powered by Arduino. There are five goals to achieve by the end of this project. First goal is to determine the SOC of each battery in a battery pack. Second goal is to establish equalization of SOC of each battery in case of different SOCs. Third goal is to prevent the battery from overcharging. Fourth goal is to prolong the life of a battery. Fifth and the last goal is to increase battery efficiency. SOC is connected to all the goals. Once SOC of all the batteries in a battery pack are equalized, the batteries will never overcharge and their life and efficiency will automatically increase.

Project Implementation Method

During the research period, we learnt that instead of using any one technique and dealing with its drawbacks, it is best to combine any two techniques to maximize benefits and minimize errors. So we chose the two famous techniques, open circuit voltage (direct measurement method) and coulomb counting (book keeping estimation method). We selected them for three reasons. Firstly they were simple to implement. Other methods such as adaptive systems are way more complex as they require proper battery models, initial parameters, enough training data and a large computing capacity. As the complexity increases, the chances for issues to arise also increase with time. Secondly they were affordable to work with. Methods such as electrochemical impedance spectroscopy and adaptive systems are cost intensive and mostly limited to laboratories for research under professionals. Lastly, according to literature if these two methods could be implemented correctly, they can provide 99% accuracy in results which is more than any other combination of techniques could provide.

Benefits of the Project

by using bms with batteries we can increse the life as well as the efficency of the batteries.

is used in electrical cars as well as hybrid cars to increse the battery life 

Technical Details of Final Deliverable

With the increase in the need for mobility and demand
for portable electronic devices, people moved towards the
batteries. The convenience brought by batteries and portable
power storage led to the invention of many useful gadgets,

devices and equipment such as cellular phones, laptops, elec-
tric vehicles, camcorders, power tools, battery operated lawn

mowers, wireless mouse, fans, lamps, and television that used
to be only available with cords.
As we know rechargeable battery has a long life but its life,
efficiency and performance keeps on decreasing with time due
to continuous charging and discharging. Suppose a battery
pack has two batteries. As the battery pack is charged, the
individual batteries charge with different levels. Similarly as
battery pack discharge, the individual batteries discharge with
different levels. The problematic point here is that if one
battery is completely charged while the other one is still

charging then by the time the latter will completely charge
the first one will be overcharged. Same is the case with
discharging. So battery packs require a system which can keep
a check on the charging and discharging of the individual
batteries. In the above example the system should disconnect
the first one to prevent its overcharging whereas the second
one keeps on charging until it is charged. Such a system is
termed as Battery management system[1].

Final Deliverable of the Project Hardware SystemType of Industry Energy Technologies OthersSustainable Development Goals Affordable and Clean Energy, Decent Work and Economic Growth, Responsible Consumption and ProductionRequired Resources

Item Name	Type	No. of Units	Per Unit Cost (in Rs)	Total (in Rs)
			Total in (Rs)	18600
Batteries	Equipment	4	1500	6000
current sensor	Equipment	4	400	1600
inverter & charger	Equipment	1	2000	2000
controller & Boards	Equipment	1	2000	2000
prototype	Miscellaneous	1	4000	4000
report printing and binding	Miscellaneous	3	1000	3000