Oleophobic Coatings for Electric Machine Stator Coolant Flow
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Solution Overview
Problem
Current thermal management systems for electric machines and power inverters face inefficiencies due to non-uniform coolant flow distribution, which can lead to localized hot spots and reduced performance, as existing methods fail to effectively manage temperature constraints in copper windings and components like IGBTs and diodes.
Innovation Solution
The application of oleophobic or hydrophobic coatings on electric machine stator end windings to control coolant flow, creating specific paths that prolong contact time with hot spots and neutral points, and the use of oleophilic or hydrophilic coatings to enhance coolant distribution, preventing flow through gaps and forming secondary coolant paths to ensure uniform cooling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional thermal management systems are used, then cooling is provided to electric machines, but non-uniform coolant flow distribution occurs leading to localized hot spots
Solution Approach 1:
The patent applies oleophobic or hydrophobic coatings to specific regions of the stator core where end windings are located. These coatings create locally varied surface properties that control coolant flow distribution, directing coolant to specific areas to achieve uniform cooling and eliminate hot spots while maintaining overall system reliability
2Productivity
If power density is increased to meet weight and cost reduction targets, then efficiency improves, but temperature constraints on copper windings and components are exceeded
Solution Approach 1:
The patent modifies the surface energy parameters of the stator core by applying oleophobic or hydrophobic coatings. This changes the wettability characteristics of the surface, thereby altering coolant flow patterns to improve heat removal efficiency and maintain temperature constraints even at higher power densities
3Temperature
If coolant flow is increased to remove localized hot spots, then temperature uniformity improves, but coolant flow control becomes insufficient with conventional methods
Solution Approach 1:
The patent implements a passive flow control system where oleophobic or hydrophobic coatings on the stator core automatically direct coolant flow based on surface energy gradients. This self-service mechanism eliminates the need for active flow control systems, achieving uniform temperature distribution through inherent surface properties rather than complex external control
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 approach improves thermal management by ensuring uniform coolant flow, reducing localized hot spots, and enhancing the reliability and efficiency of electric machines and power inverters by maintaining optimal component temperatures, thus reducing power losses and increasing the reliability of the systems.
Implementation Method 1
one or more layers of an oleophobic or hydrophobic coating overlying the end windings and configured to control a flow of coolant over the end windings
Implementation Method 2
one or more layers of an oleophobic or hydrophobic coating overlying the end windings and configured to control a flow of coolant over the end windings
Implementation Method 3
A layer of an oleophilic or hydrophilic coating may be disposed within the coolant flow path and overlying the end windings
Implementation Method 4
A layer of an oleophilic or hydrophilic coating may be disposed within the coolant flow path and overlying the end windings
Implementation Method 5
configured to direct coolant to a hot spot or a neutral point of the end windings
Data Source
AI summary
Electronic devices are disclosed including hydrophobic or oleophobic coatings that control coolant flow therein or thereon. In at least one embodiment, an electric machine is provided including a stator core defining a cavity, windings disposed within the cavity and including end windings protruding from the cavity, and one or more layers of an oleophobic coating overlying the end windings and configured to control a flow of coolant over the end windings. A method may include applying one or more layers of a oleophobic coating to end windings of an electric machine stator such that the one or more layers control a flow of coolant over the end windings. The one or more layers may define coolant flow paths, which may direct coolant to areas of the electric machine requiring additional cooling, such as hot spots or neutral points.