Project

# Title Team Members TA Documents Sponsor
54 LED Rubik's Cube
Meghan LeMay
Michael Rupp
Bryce Smith final_paper0.docx
final_paper0.pdf
other0.pdf
presentation0.pptx
proposal0.pdf
Michael Rupp netid: mrupp2
Meghan LeMay netid: mmlemay2

For this project we will be making an LED Rubik's Cube. Each sticker on the outside of the Rubix's Cube will be replaced by an LED to signal the color.

Project Modules:

1. Get multicolor LEDs to represent the sides of the Cube.
2. Implement a reset such that the LEDs will revert to a solved Rubix's Cube state.
3. Implementation of six rotation sensors to check for rotations of the Cube
4. Determine an algorithm that can coach the user to solve the LED Rubix's Cube, then implement algorithm in our Cube.

This project should be considered for Senior Design because it is multi-faceted combining design circuitry and a complex puzzle algorithm. There are similar products on the market, however they are touch screen and the cube cannot be manually rotated. The other Cubes also do not implement a solving algorithm.

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.