Electric Vehicle Stator Core Cooling Oil Flow Path Design
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Solution Overview
Problem
Current motor cooling systems for electric vehicles face challenges in achieving high power density and efficient heat dissipation due to low power density of water-cooled heat dissipation and uneven cooling effects in oil-cooled systems, leading to local overheating and reduced cooling efficiency.
Innovation Solution
A stator core design with barrel-shaped segments and corresponding housing grooves that facilitate increased oil flow and circulation, allowing cooling oil to flow through core and coil passages in series, enhancing heat transfer and cooling efficiency by ensuring larger oil flow amounts and direct contact with the stator core.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If water-cooled heat dissipation technology is used, then the motor can dissipate heat, but the power density is comparatively low and thermal resistance is high because cooling water cannot directly contact the motor assembly
Solution Approach 1:
The patent uses cooling oil as an intermediary substance that can directly contact the motor assembly (stator core and stator coil) to transfer heat, overcoming the limitation of water-cooling where water cannot directly contact the motor due to insulation requirements. The cooling oil serves as a thermal mediator with superior heat transfer properties.
Solution Approach 2:
The patent changes the cooling medium from water to oil, utilizing the different thermal properties of oil (higher boiling point, better heat transfer coefficient) to achieve higher power density and more efficient heat dissipation directly at the motor assembly.
2Temperature
If oil-cooled heat dissipation technology is used with parallel processing of stator core and end portion cooling, then the motor can dissipate heat, but the flow amount of cooling oil is small and cooling effect is poor
Solution Approach 1:
The patent merges the cooling paths for the stator core and stator coil into a series configuration, where cooling oil flows sequentially through both components. This combines the cooling function into a single high-flow path, increasing the overall cooling efficiency and allowing sufficient cooling oil flow amount to service both heat-generating components.
3Ease of operation
If cooling oil is pumped to a high position and flows down by gravity, then the cooling system can circulate oil, but the oil amount distribution is uneven and local overheating occurs
Solution Approach 1:
The patent inverts the traditional high-position pump design by placing the oil pump at the low position and the oil tank at the high position. This reversal allows the pump to push oil upward through the cooling passages, ensuring even distribution of cooling oil to all areas including the stator core and stator coil, preventing local overheating.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The enhanced cooling system achieves higher heat transfer coefficients and improved cooling efficiency, effectively addressing the challenges of power density and uneven cooling, thereby stabilizing motor operation and extending service life.
Implementation Method 1
cooling oil may flow from the core cooling oil passage groove to the coil cooling oil passage groove... effectively addressing the challenges of power density and uneven cooling, thereby stabilizing motor operation and extending service life
Implementation Method 2
the cooling oil flowing out of an oil outlet flows down by gravity, which easily causes uneven oil amount distribution
Data Source
AI summary
This application provides a motor cooling system of an electric vehicle. In the cooling system, a coil cooling oil passage includes a first oil outlet that is at an end portion of a stator core. A core cooling oil passage and the coil cooling oil passage are sequentially connected. In this case, cooling oil first enters the core cooling oil passage, and then enters the coil cooling oil passage. The core cooling oil passage extends in a circumferential direction of the stator core. The coil cooling oil passage extends in an axial direction of the stator core. A power apparatus drives the cooling oil to enter the core cooling oil passage from an oil inlet, flow through the core cooling oil passage, and enters the coil cooling oil passage from an oil through port. The cooling oil flows back to an oil return groove from the first oil outlet.