MULTI-CELL LITHIUM-ION BATTERY MANAGEMENT SYSTEM

For Electric Vehicle

Team Members• Pramit Tamrakar- Electrical Engineering• Jimmy Skadal- Electrical Engineering• Hao Wang- Electrical Engineering• Matthew Schulte- Electrical Engineering

Adviser• Ayman Fayed

Client• Adan Cervantes- Element One Systems

Team-id- SdMay11-04

Problem Statement

Develop an efficient and safe system for charging and monitoring of multi-cell series batteries in Electric Vehicles using AC to DC Switching Power Converters.

System Specifications

Functional Requirement Li-Ion Battery Management (90 cells in

series) Constant-Current Constant-Voltage (CCCV)

charging procedure Battery Gauging Temperature Monitoring Overcharge Protection

Achieve 100 miles range per charge

Non-Functional Requirements Generating a 324 VDC power bus from a

120V VAC outlet Ensuring safety

Constraints and Technology considerations Constraints: The charging process Technology:

Three Stages Charging Technology Pre - charge Constant Current stage Constant Current charging stage Constant voltage charging stage

Voltage converter Boost converter circuit MSP430 Microcontroller

Constraints: High voltage control Technology:

Scaling down by a factor about 4

(90 series cells to 24 series cells)

Market Survey Commercially available switching

mode power supply for electric vehicles is offered by Brusa.

The NLG5 provides a high voltage power source from a 120V or 240V wall outlet.

Cost: over $2,000 Brusa does not have a Battery

Management Systems.

NLG503-light battery charger. 1.6 kW 200-540V, $2,145

Risk Electric Shock: The risk of electric shock is possible when

working with a charging system. System Component Damage: As power is being applied and

the charging system is running, the risk of overheating, voltage/current spikes, and incorrect connections are possible.

Mitigation Testing and Simulation: To prevent component damage and

ensure proper design, the system will be modeled to test for expected results.

Lower Volt System: With the 42V – 86.4V scaled down system, the risk a shock is reduced.

Smart and Safe: By knowing how to be safe and building the system with human/component safety in mind will aid in avoiding risk.

Project Plan Milestones and Schedule

Cost Breakdown

Total: $2120.00

Total: $520

System Design

Functional Decomposition (Hardware)

Functional Decomposition (Software)

Large Scale design

Small Scale Design

UCC28019AEVM Boost Circuit Will supply the needed maximum 324

volts to the buck circuit for the large scale charger

350 W Power Factor Correction (PFC) boost converter

390 VDC regulated output

0.9 A of load current

Advanced fault protection

Buck circuit and Feedback Loop The buck circuit will take the

voltage generated by the boost buck down to cells

The negative feedback loop

Negative feedback tends to compare actual voltage with desired voltage and seeks to reduce the difference

Scaled down buck circuit

Inductor 100uH

Capacitor 330uF

Value of components

Battery Management System Will use TI’s processor bq76PL536EVM-3 and Aardvark USB-SPI

adaptor EVM-3 will monitor, balance and charge 24 cells in series Will use Aardvark to gather the packet of

information and display in the PC using

using Evaluation software

Implementation of the bq76pl536 with 24 series cells

Software Technology Platform• Use Ti’s Evaluation software to monitor the status of batteries

Test Plan Subsystem test:

• Boost Converter • System DC supply

• Buck Converter with MSP430 Launch Pad• All necessary voltages and currents with PWM

• Battery Management System communication• USB-SPI Processing GUI (PC)• Ability to control feedback loop from MSP430 to buck

Integration Test (scaled down):• 24 cell charge/discharge• 48V-86.4V CC (up to 3A), 86.4V CV until 0.3A

Prototype Implementations & Results

Coding for the MSP430 PWM output and ADC has been completed

Basic resistor divider input has been implemented to changed the PWM duty cycle

Components for the buck converter have been sourced

Current Project Status

Task Distribution

System DesignBuck Converter-Matt, Hao

Boost Converter-Matt, Jimmy

Battery Management System-Pramit, Matt Jimmy, Hao

Plan for Next Semester Obtain parts and evaluation module from

TI Use what we can to quickly expand the

scaled down version.• Series PCB• Use single evaluation module

Implement the buck converter. Implement communication between the

evaluation module and the MSP430 Display charging information with a pc

Questions ?