Project 1 - 1d modelling of liquid cooling system
Battery Cooling Analysis
1. Problem Description
A cooling plate is mounted with two battery modules, each consisting of multiple cells. Water is used as the coolant, flowing from a tank of limited capacity. The goal is to analyze the temperature changes in the battery and coolant with respect to:
Tank capacity
Coolant flow rate
The following properties are considered for the materials:
Battery Box Enclosure:
Surface Area: 0.2 m²
Thickness: 1 mm
Thermal Conductivity: 60 W/mK
Enclosed Air Volume: 0.05 m³
Resin Layer:
Thickness: 3 mm
Thermal Conductivity: 1.8 W/mK
Thermal Interface Material (TIM):
Thickness: 1 mm
Thermal Conductivity: 3 W/mK
Foam Insulation:
Thickness: 10 mm
Thermal Conductivity: 0.05 W/mK
Battery Module Properties:
Mass: 13.5 kg
Specific Heat Capacity: 1015 J/kgK
Thermal Conductivity: 25 W/mK
Dimensions: 390 mm × 152 mm × 108 mm
Heat Generation: 2 W
Coolant Pipe Properties:
Pipe Length: 50 mm
Cross-sectional Area: 123 mm²
Hydraulic Diameter: 12.5 mm
2. Governing Equations
Heat Conduction (Fourier’s Law):
Convective Heat Transfer (Newton’s Law of Cooling):
Energy Balance for the Battery Module:
where:
is the mass
is the specific heat capacity
is heat generated
is heat lost through conduction and convection
Energy Balance for Coolant:
where:
is the coolant flow rate
3. Numerical Implementation
Solver: Automatic fixed-step solver (1s time step)
Initial Conditions:
Battery Initial Temperature: 300 K
Coolant Initial Temperature: 295 K
Tank Capacities Considered: 2L, 5L, 10L
Coolant Flow Rates Considered: 0.1 L/min, 0.5 L/min, 1.0 L/min
4. Simulation Results & Analysis
Effect of Tank Capacity:
A larger tank (10L) results in slower coolant temperature rise, as more volume absorbs heat.
A smaller tank (2L) heats up quickly, reducing cooling efficiency.
Effect of Flow Rate:
A higher coolant flow rate (1.0 L/min) removes heat efficiently, maintaining a lower battery temperature.
A lower flow rate (0.1 L/min) causes a rapid temperature increase due to poor heat dissipation.
Temperature Evolution Over Time:
The battery temperature increases over time, but higher coolant flow rates and larger tank capacities significantly slow this increase.
The coolant temperature rises faster in systems with low tank capacity and low flow rate.
5. Conclusion
Tank capacity plays a crucial role in maintaining lower coolant temperatures. A larger tank provides better heat absorption.
Higher flow rates ensure effective cooling, maintaining lower battery module temperatures over extended periods.
The best cooling performance is observed with a 10L tank and a 1.0 L/min flow rate.
These results emphasize the importance of selecting an optimal coolant system for thermal management in battery packs. Future work can explore additional factors such as coolant type and varying heat generation rates.