Post on 08-Oct-2020
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