P18262: Battery Management System (BMS)

RIT Electric Vehicle Team

Overview Requirements

Timeline

Testing Project Results

Future Work

The Team

Sponsors

Initial Design Schematic Design PCB Layout Population and Test Integration

Reasons for the project

The team’s focus is to design and race performance electric vehicles to demon-

strate the viability of electric drivetrains

The team is creating a new motorcycle, referred to as REV 2, starting Fall 2017

An increased battery voltage necessitated a new battery management system

(BMS)

The goal is to create a new BMS that can handle the increased cell measurement

count, while decreasing the overall footprint of the design

Key Deliverables

The goal of this project is to create a system that properly manages the batteries

of the race motorcycle while in race conditions.

Functionality includes reading cell voltages, getting accurate temperature read-

ings

Project will collect data to provide the team with valuable feedback following the

race.

Major Customer Requirements

Must conform with current EVT Firmware Standards

Hardware must be able to fit within new battery packs

Must be able to function with full pack voltage of up to 500V

Must be able to measure cell voltage and cell temperature

Must be able to balance when the battery is being charged

Project Features

STM Microcontroller

Linear Technology LTC6811 Battery Balancing IC for passive battery balance

Texas Instruments Battery Fuel Gauge for State of Charge measurements

Thermistors for cell temperature measurements

Balance Circuit fusing and hardware conformal coating for safety

Indirect Contactor control for emergency pack cutoff

One master board in contact with ten slave boards located in the battery packs

Master Board Testing

Initial testing of PCB boards, including continuity tests, hardware validation and population

Population of boards was done in the SEMA SMT Lab in Building 078

X-Ray Machine was confirm correct population

High Potential Test performed on the board to ensure safety

Error Found with oscillator layout, this was corrected in a second revision, 4.1

Slave Board Testing

Similar to master board with initial testing, population, and X-Ray machine used

Tested in conjunction with Firmware team to ensure correct system integration

Board was tested to take measurements off the cells and transmit correctly to master board

Firmware Testing

Programmability of the STM microcontroller on the mas-

ter board was confirmed to work

Communications between Master and Slave Boards con-

firmed to work

IsoCAN and isoSPI correctly ran and meets communica-

tion standards

XRAY View of STM Microcontroller

isoSPI Oscilloscope Output

Overall Project Results

Communication between boards

Accurate data acquisition

Correctly balanced batteries

Successfully mounting to EVT’s Motorcycle

Etc ... Complete documentation of the project on EVT’s wiki page to ensure future members can

troubleshoot and fix

Support team during upcoming race events in the Summer of 2018

Photo of Master Photo of Boards on Bike

Picture of us mounting

boards on bike

Photo of Boards on Bike

Populated Boards

Cell Simulation Test, using EVT Motorcycle Batteries