Grading Scheme :: ECE 445 - Senior Design Laboratory

Grading Scheme

 

The grading scheme for the course, as well as links to specific requirements for each assignment/deliverable and evaluation sheets, are given in the table below. Due dates for each assignment/deliverable can be found on the course Calendar. Please note:

Below is the points breakdown for all assignments/deliverables for the course, sorted chronologically:

Item Team / Individual Score Points Evaluation Sheet**
Initial Post Individual 5  
Lab Notebook Individual 50 PDF
Lab Safety Training Individual Lab Access  
CAD Assignment Individual 10 PDF
Soldering Assignment Individual 10
Request for Approval Team 5  
Weekly TA Meetings      
Project Proposal Team 25 PDF
Team Contract Team 10  
Design Document
Requirements and Verification
Team 40 PDF
Design Review * Team 20 PDF
Board Review      
Individual Progress Report Individual 25
Mock Demo Individual 5  
Mock Presentation Individual 5  
Final Demo * Team 150 PDF
Final Presentation * Individual 50 PDF
Final Report: Technical Team 30 PDF
Final Report: English/Format Team 20 PDF
Checkout     PDF
Contract Fulfillment Team 20  
Continuing your project   Priceless  

* Grades for these will be the average of the TA and Instructor grades; peer review grades will be used to provide feedback.
** Evaluation Sheets are subject to minor changes.

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.