1. Final Presentation April 13, 2009

2. Team Members Chapman, Jonathan Duties: Recharging Major: Electrical Engineering Dang, Quoc Duties: Cell Monitoring Major: Computer Engineering Grice, Quintin Duties: Power Circuit Major: Electrical Engineering Teeple, Richard Duties: Communication Major: Computer Engineering Smith, David Duties: Fault Protection Major: Computer Engineering

3. Project Origin This project stemmed from the curiosity of Dr. Marshall Molen and the EcoCar competition. Eight lithium ion cells CAN-bus (Control Area Network)

4. Overview: Problem Solution Constraints Technical Practical Hardware Test Software Test

6. Problem When 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)

7. Solution A rechargeable battery system that offers the following: selective charging over-all current monitoring individual cell temperature and voltage monitoring CAN-bus communication

9. Technical Constraints: Name Description Battery Technology The technology used to output voltage from the REBATEM must be lithium ion cells. AccuracyVoltage: 0 to 5 volts with a tolerance of ± 0.1 volts Current: 0 to 80 amperes with a tolerance of ± 10 milliamps Temperature: -30 to 200 degrees Fahrenheit with a tolerance of ± 2 degrees Cycle Life / Capacity The REBATEM must maintain at least an 80% state of charge for the individual cells and a minimum of a 400-cycle life.

10. Technical Constraints (cont.): Name Description Fault ProtectionDisconnect the cells from the system when temperature passes 175 degrees Fahrenheit or when current passes 80 amperes. Charge cells up to 80% capacity. OutputThe output voltage must be within 14 to 16 volts. Current hour rating must be between 3.4 and 3.8 amp hours. CommunicationThe battery management system must communicate cell voltages, temperatures and current to external devices.

12. Environmental Green energy Contains no toxic metals Cadmium Lead No toxic fumes released if improperly disposed (incineration)

13. Safety Unstable - needs to be monitored Sony battery recalls UL 1642 states that users must be protected from risk of explosion or fire due to any instability of the Li-ion cells [2]. [1]

14. Top Level Diagram

15. Hardware Tests Current Sensing Voltage Sensing Temperature Sensing Charging

16. Current Sensing

17. Voltage Sensing

18. Temperature Sensing

19. Charging

20. Charge State

21. Charging Results Before Discharge After Discharge After Recharge

22. Charging Results Continue

23. Software Test Fault Protection CAN-bus Communication

24. 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.

25. Any Questions?