Axial Cooling Channels in Stator Teeth for Motor Thermal Management
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Solution Overview
Problem
Existing electric motor cooling systems for high-performance electric vehicles are inefficient in maintaining the temperature of traction motors within specified ranges, leading to hot spots and increased complexity, cost, and reduced reliability.
Innovation Solution
The proposed cooling system incorporates axial cooling channels integrated into the stator teeth with a coolant manifold assembly, featuring two interlinked manifolds that optimize coolant flow and heat transfer, reducing peak operating temperatures and simplifying manufacturing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If traditional cooling systems are used for electric motors, then the motor can operate, but peak temperatures become excessively high leading to hot spots and reduced reliability
Solution Approach 1:
The cooling system is segmented into multiple axial cooling channels distributed across the stator teeth, allowing coolant to flow through multiple separate paths rather than a single channel. This segmentation increases the total cooling surface area and distributes heat removal more effectively throughout the motor, preventing hot spots and reducing peak temperatures while improving reliability
Solution Approach 2:
Cooling channels are strategically positioned within the stator teeth where heat generation is most intense. The coolant flow is localized to the regions of highest thermal load, providing targeted cooling where it is most needed. This local quality approach ensures that critical areas with high current density and heat generation receive adequate cooling, thereby reducing peak temperatures and enhancing motor reliability
2Temperature
If complex cooling systems are implemented to reduce temperature, then temperature control improves, but system complexity and cost increase
Solution Approach 1:
The cooling channels are integrated directly into the stator structure during the stamping process, merging the cooling system with the motor's structural component. This integration eliminates the need for separate cooling jackets or external cooling assemblies, reducing overall system complexity while maintaining effective temperature control. The stator serves dual purposes as both a magnetic structure and a cooling system housing
Solution Approach 2:
The stator teeth serve multiple functions: they provide magnetic flux paths, support winding insulation, and house the cooling channels. This multi-functionality reduces the number of separate components needed in the cooling system, simplifying the overall design while achieving effective temperature control through the integrated axial cooling channels
3Ease of manufacture
If axial cooling channels are integrated into stator teeth, then manufacturing is simplified, but the stator structure becomes more complex
Solution Approach 1:
The cooling channels are formed into the stator teeth during the initial stamping process, before final assembly. This preliminary action incorporates the cooling feature into the base manufacturing step, avoiding the need for subsequent complex machining or assembly operations. By preparing the cooling channel geometry during stamping, the overall manufacturing process is simplified despite the added structural complexity
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
This solution effectively lowers peak motor temperatures by up to 40°C compared to traditional cooling systems, reduces copper losses, and simplifies the winding insertion process while minimizing system complexity and cost.
Implementation Method 1
a plurality of axial cooling channels integrated into the plurality of stator teeth... effectively lowers peak motor temperatures by up to 40°C compared to traditional cooling systems
Implementation Method 2
coolant manifold assembly integrated into the stator... optimize coolant flow and heat transfer
Data Source
AI summary
An electric motor cooling system is provided utilizing axial cooling channels that are integral to the stator teeth, thus allowing direct contact between the circulating coolant and the lamination stack and providing an efficient means of removing motor assembly heat. Additionally, as the coolant flows out of the cooling channels it impinges on the end windings, thereby providing a secondary means of cooling the motor assembly.