Electric Motor Thermal Management for EVs¶
This project presents an innovative thermal management system designed specifically for electric car motors, aiming to reduce power consumption and maintain optimal operational temperatures. Completed as part of the Design of Thermal Systems course at Boğaziçi University during Fall 2021, this project was collaboratively executed by Abdullah Gedük, Ediz Ferit Kula, and Ufuk Can Çakır.
Project Overview¶
The main objective was to develop an alternative, efficient cooling solution for electric car motors—specifically targeting the Tesla Model S motor. Traditional cooling methods rely heavily on radiators and fans, leading to increased energy consumption. Our design aimed to:
- Keep motor temperatures within recommended limits (130°C), even under extreme ambient conditions (up to 50°C).
- Minimize energy consumption for cooling.
- Eliminate conventional radiator and fan setups.
Design Concept¶
Our innovative solution uses a 90% ethylene glycol-water mixture as the coolant and consists of two main components:
- Cooling Cylinder: A copper cylindrical housing with helical rectangular ducts, enveloping the motor and capturing generated heat.
- Aluminum Heat Sink: Mounted beneath the vehicle, designed to dissipate heat effectively through convection using airflow during driving.
This combination eliminates the need for traditional radiator-fan assemblies, significantly reducing operating power.
Hardware and Geometry¶
Cooling Cylinder¶
The cooling cylinder, attached to the motor via thermal paste, incorporates a helical duct design. This geometry enhances heat transfer efficiency due to induced secondary flows:
Heat Sink¶
The aluminum heat sink beneath the car features parallel fins and internal tubing, promoting efficient heat dissipation:
Methodology¶
Our approach combined theoretical modeling with iterative optimization:
- MATLAB Optimization: Calculated optimum dimensions for fins, tubing, and ducts to minimize pump power while achieving effective cooling.
- ANSYS Fluent Simulation: Validated theoretical results, ensuring accurate predictions of heat transfer and flow characteristics.
Thermal Analysis and Optimization¶
Optimization focused on achieving:
- Maximum heat transfer efficiency.
- Minimal coolant pump energy usage.
Results from optimization provided specific geometrical configurations:
| Component | Optimized Parameters |
|---|---|
| Cooling Cylinder | 46 mm duct base, 10.12 mm duct side, 69 mm pitch |
| Heat Sink | 15.7 mm radius tubes, 11.69 m total tubing length |
| Fin Array | 20 cm fin length, 2 mm thickness, 249 fins total |
Results¶
The developed system successfully maintains motor temperatures under 130°C in ambient conditions of up to 50°C, requiring only 0.68 Watts of pump operating power—a substantial improvement compared to traditional cooling systems.
Temperature Management¶
- Motor surface temperature: 130°C (ambient at 50°C).
- Coolant temperature range: 81.3°C to 103.6°C.
Pressure and Flow Analysis¶
- Total pressure drop: 1922.1 Pa (manageable with minimal pump power).
Simulation and Validation¶
ANSYS Fluent was utilized for validation, confirming theoretical findings:
Challenges and Lessons Learned¶
- Balancing heat transfer and pressure drop was critical to optimize the energy efficiency.
- Fine-tuning the helical duct geometry significantly impacted heat transfer rates.
- Extensive simulation helped verify theoretical predictions and refine design.
Conclusion¶
Our project successfully demonstrates an energy-efficient, compact, and effective cooling system capable of maintaining optimal motor operating temperatures under challenging conditions. By eliminating traditional radiator-fan mechanisms, the system reduces complexity and operational energy demand, representing a practical and sustainable solution for electric vehicle thermal management.
Future Recommendations¶
- Experimentation with advanced coolants or refrigerants to further enhance thermal performance.
- Investigation of scaled designs suitable for other electric vehicle models.
This work provides a foundation for future developments in thermal management systems for electric vehicle technology, significantly contributing to the sustainability and efficiency of electric vehicles.