Project

# Title Team Members TA Documents Sponsor
24 Anti-lost/theft alarming system for personal belongings
 Wenhao Li
Xiying Wang
Yunchi Sun
 Igor Fedorov design_document0.pdf
final_paper0.pdf
presentation0.pdf
proposal0.pdf
Many precious personal belongings, either by theft or carelessness, are easily lost and will cause serious damage. According to a report by TechCrunch: US citizen, on average, lost one smart phone annually, which will cause 30 billion dollar loss of money in 2012. Not to mention the lost of wallet, which may cause the lost of your driving license, cash and credit cards.
Our idea is to use wireless communication technology to remarkably decrease the lost rating of those important items you carry. Since those personal belongings(i.e. wallet, cell-phone, keychain...) are supposed to be very close to you, we would pair them up(use transmitters and receiver) and make a portable device that could be easily hooked up/carried in your jacket/coats. This device will detect if any of the personal belongings are too far from you (for example more than 1 meter) and send out an alarm. The device should also be able to turned on/off manually with password. In case of theft, the stealer may trying to run away, so the alarm beep will also come from the losing personal belongings, with the alarm volume proportional to the distance between you and the potentially losing item.
This portable device should be able to pair up with multiple personal belongings, and the paired up transmitter on the personal belongings should be very small and light-weight, but also able to sent out high-volume alarm.

Active Cell Balancing for Solar Vehicle Battery Pack

Tara D'Souza, John Han, Rohan Kamatar

Featured Project

# Problem

Illini Solar Car (ISC) utilizes lithium ion battery packs with 28 series modules of 15 parallel cells each. In order to ensure safe operation, each battery cell must remain in its safe voltage operating range (2.5 - 4.2 V). Currently, all modules charge and discharge simultaneously. If any single module reaches 4.2V while charging, or 2.5V while discharging, the car must stop charging or discharging, respectively. During normal use, it is natural for the modules to become unbalanced. As the pack grows more unbalanced, the capacity of the entire battery pack decreases as it can only charge and discharge to the range of the lowest capacity module. An actively balanced battery box would ensure that we utilize all possible charge during the race, up to 5% more charge based on previous calculations.

# Solution Overview

We will implement active balancing which will redistribute charge in order to fully utilize the capacity of every module. This system will be verified within a test battery box so that it can be incorporated into future solar vehicles.

Solution Components:

- Test Battery Box (Hardware): The test battery box provides an interface to test new battery management circuitry and active balancing.

- Battery Sensors (Hardware): The current battery sensors for ISC do not include hardware necessary for active balancing. The revised PCB will include the active balancing components proposed below while also including voltage and temperature sensing for each cell.

- Active Balancing Circuit (Hardware): The active balancing circuit includes a switching regulator IC, transformers, and the cell voltage monitors.

- BMS Test firmware (Software): The Battery Management System requires new firmware to control and test active balancing.

# Criterion for Success

- Charge can be redistributed from one module to another during discharge and charge, to be demonstrated by collected data of cell voltages over time.

- BMS can control balancing.

- The battery pack should always be kept within safe operating conditions.

- Test battery box provides a safe and usable platform for future tests.