Introduction
Why we need BMS?
General function of BMS
Block diagram of BMS
BMS architecture
Battery pack – Voltage, Current, Temperature and Isolation sensing
HV contactor control
BMS communications interface
Estimation of energy and power and SOC
Methods to find SOC
Cell Balancing
Relationship between SOC and DOD
BATTERY MANAGEMENT SYSTEM (BMS) IN ELECTRIC VEHICLESBhagavathyP
Why we need BMS?
General function of BMS
Block diagram of BMS
Battery pack – Voltage, Current, Temperature and Isolation sensing
HV contactor control
BMS communications interface
Estimation of energy and power and SOC
Methods to find SOC
Cell Balancing
Relationship between SOC and DOD
The presentation gives the brief introduction of battery management systems its functions like cell protection, SOC, SOH monitoring and its applications in various fields like Smart Batteries, Battery storage power stations and electric vehicles.
Contents of this presenation entitled 'Introduction of different Energy storage systems used in Electric & Hybrid vehicles' is useful for beginners and students
types of the hybrid vehicle are discussed, series, parallel, complex, series-parallel, micro-hybrid, mild hybrid, full hybrid, and complex hybrid is discussed
BATTERY MANAGEMENT SYSTEM (BMS) IN ELECTRIC VEHICLESBhagavathyP
Why we need BMS?
General function of BMS
Block diagram of BMS
Battery pack – Voltage, Current, Temperature and Isolation sensing
HV contactor control
BMS communications interface
Estimation of energy and power and SOC
Methods to find SOC
Cell Balancing
Relationship between SOC and DOD
The presentation gives the brief introduction of battery management systems its functions like cell protection, SOC, SOH monitoring and its applications in various fields like Smart Batteries, Battery storage power stations and electric vehicles.
Contents of this presenation entitled 'Introduction of different Energy storage systems used in Electric & Hybrid vehicles' is useful for beginners and students
types of the hybrid vehicle are discussed, series, parallel, complex, series-parallel, micro-hybrid, mild hybrid, full hybrid, and complex hybrid is discussed
• Plug-in Hybrid-Electric Vehicles (PHEVs), are hybrids with high capacity batteries that can be charged by plugging them into an electrical outlet or charging station. They can store enough electricity to significantly reduce their petroleum use under typical driving conditions
A flywheel, in essence is a mechanical battery - simply a mass rotating about an axis.Flywheels store energy mechanically in the form of kinetic energy.They take an electrical input to accelerate the rotor up to speed by using the built-in motor, and return the electrical energy by using this same motor as a generator.Flywheels are one of the most promising technologies for replacing conventional lead acid batteries as energy storage systems.
Ultracapacitor based energy storage system for hybrid and electric vehiclesAkshay Chandran
Ultracapacitors and its applications in energy storage in vehicles
and hybrid energy storage systems
contents
*Introduction
*Capacitors and Ultracapacitors
*Advantages of ultracapacitors
*Conventional ESS
*HESS(Hybrid Energy Storage Systems)
*Design and Working
*Operation of Proposed Systems
*Conclusion
plug in hybrid electrical vehicals seminar ppt by MD NAWAZMD NAWAZ
A 'gasoline-electric hybrid car' or 'Plug in hybrid electric vehicle' is a vehicle which relies not only on batteries but also on an internal combustion engine which drives a generator to provide the electricity and may also drive a wheel. It has great advantages over the previously used gasoline engine that drives the power from gasoline only. It also is a major source of air pollution. The objective is to design and fabricate a two wheeler hybrid electric vehicle powered by both battery and gasoline. The combination of both the power makes the vehicle dynamic in nature. It provides its owner with advantages in fuel economy and environmental impact over conventional automobiles. Hybrid electric vehicles combine an electric motor, battery and power system with an internal combustion engine to achieve better fuel economy and reduce toxic emissions.
In HEV, the battery alone provides power for low-speed driving conditions where internal combustion engines are least efficient. In accelerating, long highways, or hill climbing the electric motor provides additional power to assist the engine. This allows a smaller, more efficient engine to be used. Besides it also utilizes the concept of regenerative braking for optimized utilization of energy. Energy dissipated during braking in HEV is used in charging battery. Thus the vehicle is best suited for the growing urban areas with high traffic. Initially the designing of the vehicle in CAD, simulations of inverter and other models are done. Equipment and their cost analysis are done. It deals with the fabrication of the vehicle. This includes assembly of IC Engine and its components. The next phase consists of implementing the electric power drive and designing the controllers. The final stage would consist of increasing the efficiency of the vehicle in economic ways.
A brief Seminar Presentation on the Hybrid Electric Vehicle (HEV) Powertrain Components, Architecture and Modes of Hybridisation. Also includes the Classification of HEV on the basis of Energy Flow.
Permanent Magnet Synchronous motor (PMSM) or Permanent Magnet AC motor:
Introduction to PMSM motor.
Types of PMSM Motor.
Mathematical modelling of PMSM motor.
Advantages and dis Advantages of PMSM motor
Creating a PowerPoint presentation on the "Types of Electric Vehicles" can be a useful way to educate your audience about the various electric vehicle (EV) technologies available. Here's a short description for each type of electric vehicle that you can include in your presentation:
Slide 1: Title
Title: "Types of Electric Vehicles"
Slide 2: Introduction
Briefly introduce the topic and its importance.
Mention the environmental and economic benefits of electric vehicles.
Slide 3: Battery Electric Vehicles (BEVs)
Describe BEVs as vehicles that run solely on electric power.
Highlight their zero-emission nature.
Mention examples like Tesla Model 3 and Nissan Leaf.
Slide 4: Plug-in Hybrid Electric Vehicles (PHEVs)
Explain PHEVs as vehicles that combine an electric motor and an internal combustion engine.
Emphasize their ability to drive on electric power and gasoline.
Mention examples like the Chevrolet Volt.
Slide 5: Hybrid Electric Vehicles (HEVs)
Define HEVs as vehicles with both an electric motor and an internal combustion engine.
Explain how they use regenerative braking to charge the battery.
Mention examples like the Toyota Prius.
Slide 6: Fuel Cell Electric Vehicles (FCEVs)
Describe FCEVs as vehicles that use hydrogen fuel cells to generate electricity to power the electric motor.
Emphasize their zero-emission nature and fast refueling times.
Mention examples like the Toyota Mirai.
Slide 7: E-Bikes and E-Scooters
Explain that electric bicycles (e-bikes) and electric scooters (e-scooters) are becoming popular forms of electric mobility.
Discuss their role in last-mile transportation.
Slide 8: Commercial Electric Vehicles
Mention electric buses, trucks, and delivery vans.
Explain how commercial EVs contribute to reducing emissions in urban areas.
Slide 9: Electric Vehicle Charging Infrastructure
Highlight the importance of charging infrastructure for EV adoption.
Discuss the types of chargers (Level 1, Level 2, DC fast chargers).
Slide 10: Government Incentives
Explain government incentives and subsidies for electric vehicle adoption.
Mention tax credits, rebates, and other benefits.
Slide 11: Environmental Benefits
Discuss how electric vehicles contribute to reducing air pollution and greenhouse gas emissions.
Highlight the positive impact on local air quality.
Slide 12: Cost of Ownership
Compare the total cost of ownership of electric vehicles to traditional gasoline vehicles.
Mention savings on fuel and maintenance.
Slide 13: Challenges and Future Outlook
Address challenges such as range anxiety, charging infrastructure gaps, and battery disposal.
Discuss the future outlook of electric vehicles and advancements in technology.
Slide 14: Conclusion
• Plug-in Hybrid-Electric Vehicles (PHEVs), are hybrids with high capacity batteries that can be charged by plugging them into an electrical outlet or charging station. They can store enough electricity to significantly reduce their petroleum use under typical driving conditions
A flywheel, in essence is a mechanical battery - simply a mass rotating about an axis.Flywheels store energy mechanically in the form of kinetic energy.They take an electrical input to accelerate the rotor up to speed by using the built-in motor, and return the electrical energy by using this same motor as a generator.Flywheels are one of the most promising technologies for replacing conventional lead acid batteries as energy storage systems.
Ultracapacitor based energy storage system for hybrid and electric vehiclesAkshay Chandran
Ultracapacitors and its applications in energy storage in vehicles
and hybrid energy storage systems
contents
*Introduction
*Capacitors and Ultracapacitors
*Advantages of ultracapacitors
*Conventional ESS
*HESS(Hybrid Energy Storage Systems)
*Design and Working
*Operation of Proposed Systems
*Conclusion
plug in hybrid electrical vehicals seminar ppt by MD NAWAZMD NAWAZ
A 'gasoline-electric hybrid car' or 'Plug in hybrid electric vehicle' is a vehicle which relies not only on batteries but also on an internal combustion engine which drives a generator to provide the electricity and may also drive a wheel. It has great advantages over the previously used gasoline engine that drives the power from gasoline only. It also is a major source of air pollution. The objective is to design and fabricate a two wheeler hybrid electric vehicle powered by both battery and gasoline. The combination of both the power makes the vehicle dynamic in nature. It provides its owner with advantages in fuel economy and environmental impact over conventional automobiles. Hybrid electric vehicles combine an electric motor, battery and power system with an internal combustion engine to achieve better fuel economy and reduce toxic emissions.
In HEV, the battery alone provides power for low-speed driving conditions where internal combustion engines are least efficient. In accelerating, long highways, or hill climbing the electric motor provides additional power to assist the engine. This allows a smaller, more efficient engine to be used. Besides it also utilizes the concept of regenerative braking for optimized utilization of energy. Energy dissipated during braking in HEV is used in charging battery. Thus the vehicle is best suited for the growing urban areas with high traffic. Initially the designing of the vehicle in CAD, simulations of inverter and other models are done. Equipment and their cost analysis are done. It deals with the fabrication of the vehicle. This includes assembly of IC Engine and its components. The next phase consists of implementing the electric power drive and designing the controllers. The final stage would consist of increasing the efficiency of the vehicle in economic ways.
A brief Seminar Presentation on the Hybrid Electric Vehicle (HEV) Powertrain Components, Architecture and Modes of Hybridisation. Also includes the Classification of HEV on the basis of Energy Flow.
Permanent Magnet Synchronous motor (PMSM) or Permanent Magnet AC motor:
Introduction to PMSM motor.
Types of PMSM Motor.
Mathematical modelling of PMSM motor.
Advantages and dis Advantages of PMSM motor
Creating a PowerPoint presentation on the "Types of Electric Vehicles" can be a useful way to educate your audience about the various electric vehicle (EV) technologies available. Here's a short description for each type of electric vehicle that you can include in your presentation:
Slide 1: Title
Title: "Types of Electric Vehicles"
Slide 2: Introduction
Briefly introduce the topic and its importance.
Mention the environmental and economic benefits of electric vehicles.
Slide 3: Battery Electric Vehicles (BEVs)
Describe BEVs as vehicles that run solely on electric power.
Highlight their zero-emission nature.
Mention examples like Tesla Model 3 and Nissan Leaf.
Slide 4: Plug-in Hybrid Electric Vehicles (PHEVs)
Explain PHEVs as vehicles that combine an electric motor and an internal combustion engine.
Emphasize their ability to drive on electric power and gasoline.
Mention examples like the Chevrolet Volt.
Slide 5: Hybrid Electric Vehicles (HEVs)
Define HEVs as vehicles with both an electric motor and an internal combustion engine.
Explain how they use regenerative braking to charge the battery.
Mention examples like the Toyota Prius.
Slide 6: Fuel Cell Electric Vehicles (FCEVs)
Describe FCEVs as vehicles that use hydrogen fuel cells to generate electricity to power the electric motor.
Emphasize their zero-emission nature and fast refueling times.
Mention examples like the Toyota Mirai.
Slide 7: E-Bikes and E-Scooters
Explain that electric bicycles (e-bikes) and electric scooters (e-scooters) are becoming popular forms of electric mobility.
Discuss their role in last-mile transportation.
Slide 8: Commercial Electric Vehicles
Mention electric buses, trucks, and delivery vans.
Explain how commercial EVs contribute to reducing emissions in urban areas.
Slide 9: Electric Vehicle Charging Infrastructure
Highlight the importance of charging infrastructure for EV adoption.
Discuss the types of chargers (Level 1, Level 2, DC fast chargers).
Slide 10: Government Incentives
Explain government incentives and subsidies for electric vehicle adoption.
Mention tax credits, rebates, and other benefits.
Slide 11: Environmental Benefits
Discuss how electric vehicles contribute to reducing air pollution and greenhouse gas emissions.
Highlight the positive impact on local air quality.
Slide 12: Cost of Ownership
Compare the total cost of ownership of electric vehicles to traditional gasoline vehicles.
Mention savings on fuel and maintenance.
Slide 13: Challenges and Future Outlook
Address challenges such as range anxiety, charging infrastructure gaps, and battery disposal.
Discuss the future outlook of electric vehicles and advancements in technology.
Slide 14: Conclusion
A modular high power battery system for pulsedShaurya Tyagi
Design of High Power battery system where supply is unavailable due to various reasons for pulsed power applications(i.e intermittent duty cycle applications).
Digitization of Battery management System and Charging by Solar PanelSHEIKHMASEMMANDAL
This is SAP sponsored Project. Here we have researched and analyzed
the battery charging and discharging pattern and optimized the BMS to display on Local Screen/Website for the parameters like temperature, battery charging rate and battery discharging rate etc.
The batteries used in electric and hybrid vehicles
consists of several cells with voltages between 3.6V battery and
4.2 V in series or parallel combinations of configurations for
obtaining the necessary available voltages in the operation of a
hybrid electric vehicle. How malfunction of a single cell affects
the behavior of the entire battery pack, BMS main function is to
protect individual cells against over-discharge, overload or
overheating. This is done by correct balancing of the cells. In
addition BMS estimates the battery charge status
Explore the innovative world of trenchless pipe repair with our comprehensive guide, "The Benefits and Techniques of Trenchless Pipe Repair." This document delves into the modern methods of repairing underground pipes without the need for extensive excavation, highlighting the numerous advantages and the latest techniques used in the industry.
Learn about the cost savings, reduced environmental impact, and minimal disruption associated with trenchless technology. Discover detailed explanations of popular techniques such as pipe bursting, cured-in-place pipe (CIPP) lining, and directional drilling. Understand how these methods can be applied to various types of infrastructure, from residential plumbing to large-scale municipal systems.
Ideal for homeowners, contractors, engineers, and anyone interested in modern plumbing solutions, this guide provides valuable insights into why trenchless pipe repair is becoming the preferred choice for pipe rehabilitation. Stay informed about the latest advancements and best practices in the field.
Immunizing Image Classifiers Against Localized Adversary Attacksgerogepatton
This paper addresses the vulnerability of deep learning models, particularly convolutional neural networks
(CNN)s, to adversarial attacks and presents a proactive training technique designed to counter them. We
introduce a novel volumization algorithm, which transforms 2D images into 3D volumetric representations.
When combined with 3D convolution and deep curriculum learning optimization (CLO), itsignificantly improves
the immunity of models against localized universal attacks by up to 40%. We evaluate our proposed approach
using contemporary CNN architectures and the modified Canadian Institute for Advanced Research (CIFAR-10
and CIFAR-100) and ImageNet Large Scale Visual Recognition Challenge (ILSVRC12) datasets, showcasing
accuracy improvements over previous techniques. The results indicate that the combination of the volumetric
input and curriculum learning holds significant promise for mitigating adversarial attacks without necessitating
adversary training.
About
Indigenized remote control interface card suitable for MAFI system CCR equipment. Compatible for IDM8000 CCR. Backplane mounted serial and TCP/Ethernet communication module for CCR remote access. IDM 8000 CCR remote control on serial and TCP protocol.
• Remote control: Parallel or serial interface.
• Compatible with MAFI CCR system.
• Compatible with IDM8000 CCR.
• Compatible with Backplane mount serial communication.
• Compatible with commercial and Defence aviation CCR system.
• Remote control system for accessing CCR and allied system over serial or TCP.
• Indigenized local Support/presence in India.
• Easy in configuration using DIP switches.
Technical Specifications
Indigenized remote control interface card suitable for MAFI system CCR equipment. Compatible for IDM8000 CCR. Backplane mounted serial and TCP/Ethernet communication module for CCR remote access. IDM 8000 CCR remote control on serial and TCP protocol.
Key Features
Indigenized remote control interface card suitable for MAFI system CCR equipment. Compatible for IDM8000 CCR. Backplane mounted serial and TCP/Ethernet communication module for CCR remote access. IDM 8000 CCR remote control on serial and TCP protocol.
• Remote control: Parallel or serial interface
• Compatible with MAFI CCR system
• Copatiable with IDM8000 CCR
• Compatible with Backplane mount serial communication.
• Compatible with commercial and Defence aviation CCR system.
• Remote control system for accessing CCR and allied system over serial or TCP.
• Indigenized local Support/presence in India.
Application
• Remote control: Parallel or serial interface.
• Compatible with MAFI CCR system.
• Compatible with IDM8000 CCR.
• Compatible with Backplane mount serial communication.
• Compatible with commercial and Defence aviation CCR system.
• Remote control system for accessing CCR and allied system over serial or TCP.
• Indigenized local Support/presence in India.
• Easy in configuration using DIP switches.
Vaccine management system project report documentation..pdfKamal Acharya
The Division of Vaccine and Immunization is facing increasing difficulty monitoring vaccines and other commodities distribution once they have been distributed from the national stores. With the introduction of new vaccines, more challenges have been anticipated with this additions posing serious threat to the already over strained vaccine supply chain system in Kenya.
Forklift Classes Overview by Intella PartsIntella Parts
Discover the different forklift classes and their specific applications. Learn how to choose the right forklift for your needs to ensure safety, efficiency, and compliance in your operations.
For more technical information, visit our website https://intellaparts.com
Final project report on grocery store management system..pdfKamal Acharya
In today’s fast-changing business environment, it’s extremely important to be able to respond to client needs in the most effective and timely manner. If your customers wish to see your business online and have instant access to your products or services.
Online Grocery Store is an e-commerce website, which retails various grocery products. This project allows viewing various products available enables registered users to purchase desired products instantly using Paytm, UPI payment processor (Instant Pay) and also can place order by using Cash on Delivery (Pay Later) option. This project provides an easy access to Administrators and Managers to view orders placed using Pay Later and Instant Pay options.
In order to develop an e-commerce website, a number of Technologies must be studied and understood. These include multi-tiered architecture, server and client-side scripting techniques, implementation technologies, programming language (such as PHP, HTML, CSS, JavaScript) and MySQL relational databases. This is a project with the objective to develop a basic website where a consumer is provided with a shopping cart website and also to know about the technologies used to develop such a website.
This document will discuss each of the underlying technologies to create and implement an e- commerce website.
Overview of the fundamental roles in Hydropower generation and the components involved in wider Electrical Engineering.
This paper presents the design and construction of hydroelectric dams from the hydrologist’s survey of the valley before construction, all aspects and involved disciplines, fluid dynamics, structural engineering, generation and mains frequency regulation to the very transmission of power through the network in the United Kingdom.
Author: Robbie Edward Sayers
Collaborators and co editors: Charlie Sims and Connor Healey.
(C) 2024 Robbie E. Sayers
Saudi Arabia stands as a titan in the global energy landscape, renowned for its abundant oil and gas resources. It's the largest exporter of petroleum and holds some of the world's most significant reserves. Let's delve into the top 10 oil and gas projects shaping Saudi Arabia's energy future in 2024.
Courier management system project report.pdfKamal Acharya
It is now-a-days very important for the people to send or receive articles like imported furniture, electronic items, gifts, business goods and the like. People depend vastly on different transport systems which mostly use the manual way of receiving and delivering the articles. There is no way to track the articles till they are received and there is no way to let the customer know what happened in transit, once he booked some articles. In such a situation, we need a system which completely computerizes the cargo activities including time to time tracking of the articles sent. This need is fulfilled by Courier Management System software which is online software for the cargo management people that enables them to receive the goods from a source and send them to a required destination and track their status from time to time.
Democratizing Fuzzing at Scale by Abhishek Aryaabh.arya
Presented at NUS: Fuzzing and Software Security Summer School 2024
This keynote talks about the democratization of fuzzing at scale, highlighting the collaboration between open source communities, academia, and industry to advance the field of fuzzing. It delves into the history of fuzzing, the development of scalable fuzzing platforms, and the empowerment of community-driven research. The talk will further discuss recent advancements leveraging AI/ML and offer insights into the future evolution of the fuzzing landscape.
Quality defects in TMT Bars, Possible causes and Potential Solutions.PrashantGoswami42
Maintaining high-quality standards in the production of TMT bars is crucial for ensuring structural integrity in construction. Addressing common defects through careful monitoring, standardized processes, and advanced technology can significantly improve the quality of TMT bars. Continuous training and adherence to quality control measures will also play a pivotal role in minimizing these defects.
Welcome to WIPAC Monthly the magazine brought to you by the LinkedIn Group Water Industry Process Automation & Control.
In this month's edition, along with this month's industry news to celebrate the 13 years since the group was created we have articles including
A case study of the used of Advanced Process Control at the Wastewater Treatment works at Lleida in Spain
A look back on an article on smart wastewater networks in order to see how the industry has measured up in the interim around the adoption of Digital Transformation in the Water Industry.
2. Overview
• Battery Basics
• Introduction
• Why we need BMS?
• General function of BMS
• Block diagram of BMS
• BMS architecture
• Battery pack – Voltage, Current, Temperature and Isolation sensing
• HV contactor control
• BMS communications interface
• Estimation of energy and power and SOC
• Methods to find SOC
• Cell Balancing
• Relationship between SOC and DOD
• Conclusion
2
4. Difference Between Cell, Module & Pack
• Battery cell:
• Unit of a battery that exerts electric energy by charging and discharging. Made by
inserting anode, cathode, separator and electrolyte into a aluminum case.
• Battery module:
• Connecting a number of cells in parallel or series is called battery module.
• Battery Pack:
• Composed of battery module connected in series and parallel.
4
9. C – Rate
• Battery current handling capability
• It is a constant current charge or discharge rate, which the battery can sustain for one hour
• For eg : 12V,20Ah battery
• 20A can be deliver at one hour or 2A for 10hrs
• 1C rate - 20A for 1hr
• 2C rate - 40A for 30min
• 3C rate - 60A for 15min
• 0.5C rate - 10A for 2hrs
• 0.1C rate - 2A for 10hrs
9
11. Introduction to BMS
• An electric vehicle generally contains the following major components: an electric motor, a motor controller,
a traction battery, a battery management system, a wiring system, a vehicle body and a frame.
• The battery management system is one of the most important components, especially when using lithium
batteries.
• The lithium cell operating voltage, current and temperature must be maintained within the “Safe Operation
Area” (SOA) at all times.
• To maintain the safe operation of these batteries, they require a protective device to be built into each
pack is called battery management system (BMS).
• BMS make decisions on charge and discharge rates on the basis of load demands, cell voltage, current, and
temperature measurements, and estimated battery SOC, capacity, impedance, etc. BMS is a part of
complex and fast-acting power management system.
11
12. History of BMS
• On 7th January 2013, a Boeing 787 flight was parked for maintenance, during that time a mechanic noticed
flames and smoke coming from the Auxiliary power unit (Lithium battery Pack) of the flight. On 16th
January 2013 another battery failure occurred in a 787 flight operated by All Nippon Airways which
caused an emergency landing at the Japanese airport.
• After a series of joint investigation by the US and Japanese, the Lithium battery Pack of B-787 went
through a CT scan and revealed that one of the eight Li-ion cell was damaged causing a short circuit
which triggered a thermal runaway with fire.
• This incident could have been easily avoided if the Battery management system of the Li-ion battery pack
was designed to detect/prevent short circuits.
12
13. Why we need BMS?
• Detects unsafe operating conditions and responds.
• Protects cells of battery from damage in abuse and failure cases.
• Prolongs life of battery. Maintains battery in a state.
13
14. General function of BMS
• Sensing and high-voltage control
Measure voltage, current, temperature, control contactor, pre-charge; ground-fault detection, thermal
management.
• Protection
Over-charge, over-discharge, over-current, short circuit, extreme temperatures.
• Interface
Range estimation, communications, data recording, reporting.
• Performance management
State of charge (SOC) estimation, power limit computation, balance and equalize cells.
• Diagnostics
Abuse detection, state of health (SOH) estimation, state of life (SOL) estimation.
14
16. BMS architecture
• A modular battery pack suggests a hierarchical master – slave BMS
design.
• There is normally a single “master” unit for each pack.
16
17. BMS master role
• Control contactors that connect battery to load.
• Monitor pack current, isolation. Communicate with BMS slaves. Control thermal-management.
• Communicate with host application controller.
17
18. BMS slave role
• Measure voltage of every cell within the module.
• Measure temperatures.
• Balance the energy stored in every cell within the module.
Communicate this information to the master.
18
19. Battery pack – Voltage sensing
• Why we consider cell voltage?
1. Indicator of relative balance of cells.
2. Input to most SOC and SOH estimation algorithms.
3. Safety: overcharging a lithium-ion cell can lead to “thermal runaway,” so we cannot skip
measuring any voltages.
• Voltage is measured using an analog to digital converter(ADC). A direct-conversion or flash ADC.
• Successive approximation. Delta-sigma.
• Special chipsets are made to aid high-voltage BMS design. Multiple vendors make chipsets (e.g., Analog
Devices, Maxim, Texas Instruments).
19
20. Battery pack – Current sensing
• Why battery pack electrical current measurements are required?
1. To monitor battery-pack safety. To log abuse conditions.
2. By most state-of-charge and state-of-health algorithms.
• There are two basic methods to measure electrical current:
1. Using a resistive shunt.
2. Using a Hall-effect mechanism.
20
21. Battery pack – Temperature sensing
• Why battery pack temperature measurements are required?
1. Battery cell operational characteristics and cell degradation rates are very strong functions of
temperature.
2. Unexpected temperature changes can indicate cell failure or impending safety concern.
• There are two methods to measure temperature : Using a thermocouple and using a thermistor.
• Thermistor has two types.
1. Negative-temperature-coefficient (NTC) thermistors.
2. Positive-temperature-coefficient (PTC) thermistors.
21
22. Battery pack – Isolation sensing
• Why isolation sensing is required?
1. Isolation sensing detects presence of a ground fault. Primary concern is safety.
• In a vehicle application, we must maintain isolation between high-voltage battery pack and chassis of the
vehicle.
• FMVSS says isolation is sufficient if less than 2mA of current will flow when connecting chassis ground to
either the positive or negative terminal of the battery pack via a direct short.
22
23. HV contactor control
• Disconnecting or connecting a battery pack at both
terminals requires high-current capable relays or
“contactors”.
• A low-voltage/low-current signal activates the
contactor, closing an internal switch that connects
its main terminals.
• If both contactors were closed simultaneously,
enormous current would flow instantly and blowing
a fuse So, a third “pre-charge” contactor is used.
23
24. BMS communications interface
• Control Area Network (CAN) bus is industry ISO standard for on-board vehicle communications.
• Two-wire serial bus designed to network intelligent sensors and actuators; can operate at two rates:
1. High speed (e.g., 1M Baud): Used for critical operations such as engine management, vehicle
stability, motion control.
2. Low speed (e.g., 100 kBaud): Simple switching and control of lighting, windows, mirror
adjustments, and instrument displays etc.
• The LIN Bus is another automotive communications standard, similar to the CAN Bus. It is a single
wire Local Interconnect Network operating at 20 KBaud with low cost IC solutions.
• The FlexRay Bus can support fast responding dynamic control systems rather than just the simpler
sensors and actuators per- mitted with the CAN Bus. The FlexRay data payload per frame is 20 times
greater than the CAN Bus.
24
25. BMS communications interface
• The Integrated Circuit (I2C) Bus was a low speed bus originally designed for use between internal
modules within a system rather than for external communications. It is a bidirectional, half duplex, two
wire synchronous bus. It runs with data rates up to 3.4 Mbits/s and is suitable for Master - Slave applica-
tions. Multiple slaves are possible but only a master can initiate a data transfer. Typically used for internal
communications within embedded systems such as a BMS.
• The SMBus (System Management Bus) is a two wire, 100 KHz, serial bus designed for use with low
power Smart Battery Systems (SBS) with the limited objectives of interconnecting Smart Batteries which
have built in intelligence, with their associated chargers.
25
26. Estimation of energy and power
• Cannot directly measure the available energy or available power Therefore, must estimate SOC, SOH.
• To estimate energy, we must know all cell states-of-charge and charge capacities.
• To estimate power, we must know all cell states-of-charge and resistances.
• Available inputs include all cell voltages, pack current, and temperatures of cells or modules.
26
27. State of Charge (SOC)
• The SOC of a battery is defined as the ratio of its current capacity Q(t) to the nominal capacity
Q(n).The nominal capacity is given by the manufacturer and represents the maximum amount of charge
that can be stored in the battery.
• The SOC can be defined as follows:
• SOC changes only due to passage of current, either charging or discharging the cell due to external
circuitry, or due to self- discharge within the cell.
SOC(t) =
Q(t)
Q(n)
27
28. Why SOC is important?
• Prevent overcharge or discharge.
• Improve the battery life. Protect battery.
• Improves the battery performance.
• For cell balancing applications, it is only necessary to know the SOC of any cell relative to the other
cells in the battery chain.
28
29. Methods to find SOC
• Direct measurement: this method uses physical battery properties, such as the voltage and impedance of
the battery.
• Book-keeping estimation: this method uses discharging current as the input and integrates the discharging
current over time to calculate the SOC.
• Adaptive systems: the adaptive systems are self designing and can automatically adjust the SOC for
different discharging conditions.
• Hybrid methods: combining any two methods to form a hybrid models of each SOC estimation.
29
30. Methods to find SOC
• Direct measurement:
1. Open circuit voltage method Terminal voltage method Impedance method
2. Impedance spectroscopy method
• Book-keeping estimation:
1. Coulomb counting method
2. Modified Coulomb counting method
30
31. Methods to find SOC
• Adaptive systems:
• BP neural network RBF neural network Support vector machine Fuzzy neural
network Kalman filter
• Hybrid systems:
• Coulomb counting and EMF combination Coulomb counting and Kalman filter combination
Per-unit system and EKF combination
31
32. Cell Balancing
• Cell Balancing scheme to prevent individual cells from becoming over stressed. These systems monitor the
voltage across each cell in the chain.
• Active cell balancing methods remove charge from one or more high cells and deliver the charge to one
or more low cells.
• Dissipative techniques find the cells with the highest charge in the pack, indicated by the higher cell
voltage, and remove excess energy through a bypass resistor until the voltage or charge matches the
voltage on the weaker cells is known as passive balancing.
• Charge limiting is a crude way of protecting the battery from the effects of cell imbalances is to simply
switch off the charger when the first cell reaches the voltage which represents its fully charged state (4.2
Volts for most Lithium cells) and to disconnect the battery when the lowest cell voltage reaches its cut off
point of 2 Volts during discharging.
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33. Cell Balancing
• Lossless balancing is a superior way of cell balancing by means of software control. All of these balancing
techniques depend on being able to determine the state of charge of the individual cells in the chain.
• More precise methods use coulomb counting and take account of the temperature and age of the cell as
well as the cell voltage.
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34. Relationship between SOC and DOD
• A battery’s depth of discharge (DoD) indicates the percentage of the battery that has been discharged
relative to the overall capacity of the battery.
• Depth of Discharge (DOD) is the fraction or percentage of the capacity which has been removed
from the fully charged battery. Conversely, the State of Charge (SOC) is the fraction or percentage of
the capacity is still available in the battery.
• A battery that is at 100 percent SOC is at 0 percent DOD. A battery at 80 percent SOC is at 20
percent DOD.
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35. Conclusion
• As batteries are the core energy sources in EVs and HEVs, their performance greatly impacts the
salability of EVs. Therefore, manufacturers are seeking for breakthroughs in both battery technology and
BMS.
• The major concerns of BMS were discussed in this presentation. Due to varying situations in real-world
applications, a standard solution was not wanted. Based on the specific situation, different strategies
should be applied to improve and optimize the performance of BMS in future EV and HEV.
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