senior design ii final presentation december 1, 2009
TRANSCRIPT
Senior Design II
Final Presentation
December 1, 2009
Team MembersJonathan Chapman
Duties: Recharging Major: Electrical Engineering
Quoc Dang Duties: Recharging Major: Computer Engineering
Quintin Grice
Duties: Power Circuit Major: Electrical Engineering
Richard Teeple
Duties: Communication, System Monitoring Major: Computer Engineering
David Smith
Duties: Fault Protection, System Monitoring
Major: Computer Engineering
OverviewProblemSolutionConstraints
TechnicalPractical
DesignPCBsEnclosureBill of Materials
Testing
ProblemWhen dealing with lithium ion battery systems, the
following aspects must be taken into consideration:Safety
Fire and Explosion
Communication CAN-bus
System Life Weakest Link (individual cell)
SolutionA rechargeable battery system that offers the
following:Total output current monitoring Ambient temperature monitoringIndividual cell voltage monitoringCAN-bus communication
Technical ConstraintsName
Description
Battery Technology
The technology used to output voltage from the REBATEM must be lithium ion cells.
Accuracy Voltage: 0 to 5 volts with an accuracy of ± 0.1 voltsCurrent: 0 to 6 amperes with an accuracy of ± 20 milliampsTemperature: -30 to 200 °F with an accuracy of ± 2 °F
Capacity /Cycle Life
The REBATEM must maintain at least an 80% state of charge for the individual cells and a minimum of a 400-cycle life.
Technical Constraints (cont.)Name
Description
Fault Protection Disconnect the cells from the system when temperature passes 175 °F or when current passes 10 amps.
Output Output voltage must be within 12 to 16 volts.
Communication The battery management system must communicate cell voltages, temperature and current to external devices.
Environmental•Green energy•Contains no toxic metals
• Cadmium• Lead
Safety•Unstable - needs to be monitored
•Sony battery recalls•UL 1642
[1]
PCB - Main
PCB - Charge
PCBsCharge Board PCB Main Board PCB
EnclosureSide ViewInside View
Enclosure
Front View Back View
Bill of MaterialsMain Board (X1)
PIC24HJ32 (1) $7.00
INA219 (1) $3.76
ISL9208IRZ (1) $7.51
MCP2551 (1) $1.12
Other Discrete Components $20.00
PCB (1) $33.00
Charge Board (x1)
MOSFET 2N-CH (1) $1.20
MAX745EAP (1) $11.61
MAX931CPA (1) $2.46
Other Discrete Components $20.00
PCB (1) $33.00
Enclosure
(Estimated) $50.00
Total: $190.65
Total Output
Accuracy-Voltage Setup (No Load)
VM-1 3.69
3.69
3.69
3.69
BMS-1
3.69
3.70
3.69
3.71
Tol-1 0.00
0.01
0.00
0.02
VM-2 4.00
4.00
4.00
4.00
BMS-2
4.02
4.02
4.03
4.04
Tol-2 0.02
0.02
0.03
0.04
Results
Accuracy-Current Setup (Test Load = 14.9 Ω)
BMS-Voltage (V)
Shunt (A)
Ammeter (A)
Tol
15.03 0.975 0.96 0.015
15.04 0.975 0.96 0.015
15.04 0.975 0.96 0.015
15.02 0.975 0.96 0.015
15.03 0.975 0.96 0.015
15.04 0.975 0.96 0.015
Results
Accuracy-Temperature Setup (No Load)
Monitored (°C) Measured (°C) Absolute Error
21.28 21.2 0.08
21.32 21.3 0.02
33.25 32.4 0.85
32.31 32.4 0.09
31.93 32.3 0.37
33.63 33.2 0.43
Results
CAN Communication
Charging Cells
3
3.05
3.1
3.15
3.2
3.25
3.3
3.35
3.4
3.45
3.5
0 20 40 60 80 100 120 140 160 180
Time (s)
Vo
ltag
e (V
) Cell 1
Cell 2
Cell 3
Cell 4
Any Questions?
References:[1] [Online] Available: http://www.gadgetreview.com/wp-content/uploads/2006/08/explosion_dcrop1.jpg.
[2] “Lithium Batteries.” [Online]. Available: http://ulstandardsinfonet.ul.com/scopes/scopes.asp?fn=1642.html.