Project

# Title Team Members TA Documents Sponsor
27 Weather-Adaptive Windows
Andy Lai
Joseph Zatarski
Michael Wu
Michael Genovese appendix0.ino
appendix0.sch
appendix0.brd
appendix0.brd
appendix0.brd
appendix0.sch
appendix0.sch
final_paper0.pdf
photo0.png
presentation0.pptx
proposal0.pdf
GROUP MEMBERS
Andy Lai, Michael Wu, Joseph Zatarski

TITLE
Weather-Adaptive Windows

DESCRIPTION
There are a couple of unfortunate situations that may arise from leaving windows open in attempts to regulate temperature during the night or while away from the house. If the temperature outside becomes undesirable while away from the house, it makes for a very unpleasant experience when re-entering; leaving the windows open at night could have adverse health effects. A storm blowing in unknowingly could result in undesired humidity or water in the living space.

The solution is to have a window that closes based on a suite of external sensors, like temperature and rain. When a close-window-condition is met, Several IR sensors will work to evaluate if the window is opened or closed, thus evaluating the need to activate the motor. The IR sensors will be polled regularly to check for obstructions.

There are rain, temperature, and pressure sensors that can be purchased online. We also plan on having the temperature setting to be user-programmable via software threshold. To power our project, we’ll be using wall voltage coupled with appropriate AC-DC converters to step voltages down to appropriate levels for circuit elements. We plan on using a microcontroller to be the interface between our sensors and motor. We will have the machine shop modify a window to be opened and closed by a motor

In summary, we need a sensor module that feeds into the control module which will control the mechanical elements of our project.

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.