Stator Slot Coolant Flow for Direct Conductor Cooling
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Solution Overview
Problem
Conventional electric motors in hybrid and battery electric vehicles generate significant heat, which diminishes their performance, and existing cooling systems are insufficient for effective heat dissipation, particularly at the stator assembly.
Innovation Solution
The electric motor design incorporates coolant channels and slots within the stator assembly, allowing direct coolant flow to contact conductors and enhance cooling, while maintaining high voltage electrical isolation through the use of liners and inserts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional cooling systems are used in electric motors, then the structure is simple, but heat dissipation is insufficient and performance diminishes
Solution Approach 1:
The cooling channels are integrated directly into the stator slots, merging the cooling system with the stator structure. This eliminates the need for separate cooling components while achieving direct coolant contact with conductors, thereby improving heat dissipation without proportionally increasing device complexity
Solution Approach 2:
The coolant channels are nested within the stator slot structure, with channels positioned at different radial locations (first radial location for outer channels, second radial location for inner channels). This nested arrangement allows efficient heat removal from conductors while maintaining a compact stator design
2Productivity
If coolant channels are integrated into stator slots, then cooling efficiency improves by 50%, but manufacturing complexity increases
Solution Approach 1:
The stator assembly is segmented into multiple laminations, each with integrated coolant channels. This segmentation allows the cooling channels to be formed during lamination manufacturing processes, and the modular structure facilitates assembly while maintaining high cooling efficiency
Solution Approach 2:
The stator slots serve dual functions: housing the conductors and containing the coolant channels. This multi-functionality reduces the need for separate cooling components, potentially simplifying manufacturing despite the integrated channel design
3Temperature
If direct coolant contact with conductors is implemented, then thermal resistance decreases, but electrical isolation requirements become more challenging
Solution Approach 1:
The coolant channels are positioned at specific radial locations within the stator slots (first radial location and second radial location) to optimize heat removal from conductors while maintaining adequate electrical clearance. This localized positioning achieves low thermal resistance without compromising electrical isolation reliability
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 design significantly improves cooling effectiveness by up to 53%, reduces thermal resistance, and maintains electrical isolation, enhancing overall motor performance and reducing hot spots.
Implementation Method 1
Coolant flow occurs through the coolant channels, to the slots, and into contact with conductors that reside at the slots
Implementation Method 2
Coolant flow occurs through the coolant channels, to the slots, and into contact with conductors that reside at the slots
Data Source
AI summary
An electric motor can be employed for use in a hybrid electric vehicle (HEV) or in a battery electric vehicle (BEV), as example applications. In an implementation, the electric motor has a stator assembly with a multitude of laminations exhibiting an axially-stacked arrangement. The laminations establish coolant channels at a radially-outboard location thereof, and establish slots at a radially-inboard location thereof. Conductors such as windings are disposed at the slots. Some or more of the coolant channels and some or more of the slots are in fluid communication with each other whereby coolant flows through the coolant channels, to the slots, and into contact with the conductors. Enhanced cooling effectiveness at the stator and elsewhere results.