project no. 4203-1535 slides2
TRANSCRIPT
EV Battery Gauge Design:Project in progress
Project no. 4203-1535
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Project Team Members and Roles Name: Pat McGoldrickRole: Industry Mentor (Creative Power Technologies)Contact Details: [email protected]
Name: Grahame HolmesRole: University Supervisor (RMIT University)Contact Details: [email protected]
Names: Curtis Moses, Declan Lammers, Ilia Andreev, John Francia, Long Nguyen, Olivia McCombeRoles: Student Researchers and Designers Contact Details: [email protected]
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Nominal full charge 6.630 kWh
Energy drawn over 22 km 6.596 kWh
SoC after 22 km
<1 %
Project BackgroundFrom Lap Simulator of RMIT Car
in Formula Student Event:
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Project Background
Image sources: plugincars.com, RMIT Electric Racing
Fuel gauge for an EV battery State of Charge (SoC) SoC % of maximum charge remaining
BENEFITS:• Driver control of battery• Foundation for automated
battery management
CHALLENGES:• Direct measurement inaccurate• Many estimation techniques
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Project Background
Image sources: plugincars.com, RMIT Electric Racing
Objectives:
Battery gauge- Li-ion chemistry
- Amateur EVs
SoC EstimationProgram
Display + ValidationPrograms
Product
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Discharge + Measurement
Circuit
SoC EstimationProgram
Display + ValidationPrograms
Our Estimation System
Battery
Image sources: Arduino, pngwebicons.com
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Project PlanResearch Phase:
Project Benefit, Scope, + Estimation Techniques
1 March – May 30
Circuit Team Arduino Team Display + Validation TeamDischarge/measurement circuit built
19 July
SoC estimation program (simulation data)
Display code
Open-circuit-voltage measurements
2 August
Circuit-Arduino connection code
2 August
Arduino-computer connection
Circuit-Arduino operation
31 August
Validation code
Arduino-computer operation
15 September
GANTT Chart Extract
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SoC Estimation Program
1. Before charging/discharging: estimate initial SoC
2. During charging/discharging: ± charge entering/exiting
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Constant Current Pulses discharge
battery
1. Estimate Initial SoCOpen Circuit Voltage (OCV) – SoC Table
Measurement Circuit
Test PhaseOCV SoC
3.75 100%
3.70 99%
3.65 98%
SWITCHVOLTAGESENSE
OCV = Battery Terminal Voltage
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1. Estimate Initial SoCOpen Circuit Voltage (OCV) – SoC Table
Initial SoC
Measurement Circuit
Estimation Phase
Battery TerminalVoltage
OCV SoC
3.75 100%
3.70 99%
3.65 98%
VOLTAGESENSE
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Coulomb Counting2. ± Charge Entering/Exiting
Convert Current to
Charge (Coulombs)
± From Initial SoC
Measurement Circuit
CURRENTSENSOR
Currentover Time
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Coulomb Counting2. ± Charge Entering/Exiting
Convert Current Charge (Q) (in coulombs)
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Coulomb Counting2. ± Charge Entering/Exiting
SoC Calculation
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Components Focus
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BatteryLithium-Ion ChemistryOne Cell3.7V, 100mAh
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Discharge + Measurement Circuit
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Discharge + Measurement Circuit
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Discharge + Measurement Circuit
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SoC Program
Arduino
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Display ProgramMATLAB
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MATLABBattery Simulation Model
Validation Program Validation Program
Estimate Initial SoCSimulation:
Pre-defined Variable
Read CurrentSimulation: Data
Array
Identify SoC for Current Range
Switch Statements
Current Range-SoC Look-Up Table
Outputs:Voltage
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Results + Conclusions
Achievements
Current Product Limitations
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Acknowledgements AutoCRC
Professor Grahame Holmes
Pat at Creative Power Technologies
RMIT Electric Racing Team
RMIT Staff