Lithium Ion Battery Management System

Project Title

Lithium Ion Battery Management System

Project Area of Specialization Electrical/Electronic EngineeringProject Summary

Today’s electronic devices have higher mobility and are greener than ever before. Battery advancements are fuelling this progress in a wide range of products from portable power tools to plug-in hybrid electric vehicles, wireless speakers and for storage of energy with inverters for daily use. In recent years, the efficiency of a battery in terms of how much power it can output with respect to size and weight has dramatically improved. Think about how heavy and bulky a car battery is, its main purpose is to start the car. With recent advancements, you can purchase a lithium-ion battery to jump start your car, and it only weighs a couple of pounds and is the size of your hand. Also think about dry cell battery and other kind of batteries whose life is not more than two to three years. Where the Li-ion battery’s life is 7 years and after 7 years, its charging capacity becomes 70%.  
But the problem is that when the Li-ion battery is over charge or discharge and due to the heat dissipation, the time of the Li-ion battery decreases.  
Energy storage system technology is still the blockage for the electric vehicle industry. Lithium-ion batteries have attracted considerable attention due to their high energy density, lifespan, nominal voltage, power density, and cost. Smart battery management system (BMS) is one of the essential components; it not only measures the states of battery accurately, but also ensures safe operation and prolongs the battery life.

Project Objectives

Objectives of Project are :
 

•  Mathematical model of Li-ion Battery.
• Existing BMS hardware solution.
• Electronic Design and Fabrication of BMS.
• Verification and Validation of Flaws.
• Cell protection
• Battery life
• Functional use for an application

Project Implementation Method

Today's Li-ion batteries need to be precisely supervised during all their working cycles to limit their charges and discharges, to ensure their security and improve their lifetime.
Battery management is currently performed by monitoring battery cell voltages: charging is interrupted when the voltage of the first cell of the serial arrangement exceeds a threshold value (charging then goes forward with a lower current for the remaining cells).

Battery discharge is managed similarly and is interrupted when the voltage of first battery cell falls below a threshold value. The remaining energy in the other cells of the serial arrangement is not used. Hence, the energy stored into the battery is not fully exploited, which limits the autonomy of the supplied system.

Non-dissipative solutions to exchange energy between cells so as to maintain the cells balanced have been reported; yet, they require a large number of DC/DC converters with associated size, weight and price drawbacks. To overcome these limitations and to remove the battery charger and output converter (DC/DC or DC/AC converter to supply
the load), we propose a full converter based on battery cell switching, to adjust the battery pack output voltage to the effective need in real time and maintain the battery cells balanced. The architecture we developed consists in connecting or disconnecting in real time each cell placed in the serial arrangement.

Moreover, for the transistor driving part, a distributed electronic is placed in front of each cell of the serial arrangement. Each distributed electronic circuit is able to drive up to 14 to 20 transistors, to carry out local measurements (temperature, current, voltage) and to calculate the estimated State of Charge of the local cell.

Benefits of the Project

Benefits of battery management system are:

• Avoid costly downtime. 

• Battery life by replacing batteries at the correct time.

• Improve safety by reducing the need for physical contact with the battery bank.

• Make informed decisions using accurate information that is automatically captured and consistently reported.

• Reduce maintenance and replacement costs by monitoring and performing preventative maintenance.

• Save time by having remote access to battery data and pinpointing faults to specific individual batteries.

• Maintain security and overall systems integrity by limiting access to sensitive areas for external service providers.

Technical Details of Final Deliverable

BMS implements an extensive list of features designed to protect the battery pack. These features include:

• State of charge calculations.
• Cell over-voltage and under-voltage protection.
• Intelligent battery balancing (passive).
• Battery charger control.
• Pack temperature monitoring.
• Monitors health of battery pack.

Final Deliverable of the Project HW/SW integrated systemCore Industry ManufacturingOther Industries Education , IT , Transportation , Security Core Technology Clean TechOther Technologies Wearables and ImplantablesSustainable Development Goals Good Health and Well-Being for People, Quality Education, 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)	72900
Lithium ion Battery (Pack of 4)	Equipment	100	175	17500
Electric Vacuum Solder Sucker Electric Desoldering Pump Iron Tool Us P	Equipment	1	5600	5600
1 Meter Heat Shrink Tube Size 1Mm	Equipment	10	30	300
Battery spot welder 18650 battery welding machine 220V/110V	Equipment	1	29000	29000
Lithium Battery Welding Fixture Moveable Battery Clamp	Equipment	1	6000	6000
transistor	Equipment	250	10	2500
cable ties	Equipment	200	10	2000
other equipment (capacitor, wires, resistors)	Miscellaneous	200	50	10000