Direct-Cooled Flat Wire Winding for Lower EV Motor Heat Loss
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Solution Overview
Problem
The existing cooling solutions for flat wire windings in electric vehicle motors have low efficiency, leading to excessive heat loss and temperature rise, which affects the motor's efficiency and safety.
Innovation Solution
A flat wire motor with directly cooled flat wire windings, where coolant grooves are designed to directly cool the flat wires, increasing the contact area and improving cooling efficiency by using gaps and protrusions to stabilize the wires and enhance electromagnetic performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional cooling solutions are used for flat wire windings, then the structure is simple, but cooling efficiency is low and heat loss is excessive
Solution Approach 1:
The cooling grooves are nested within the stator core structure, with coolant channels integrated into the stator teeth and yoke. The flat wire windings are nested within the stator bore, and cooling grooves are formed between the windings and the stator core, creating a nested configuration that enables direct cooling without adding external cooling components.
Solution Approach 2:
A liquid coolant is circulated through the cooling grooves in the stator core to directly remove heat from the flat wire windings. The coolant flow path is designed to maximize heat transfer efficiency, with inlet and outlet ports positioned to create effective circulation through the cooling channels.
2Temperature
If cooling grooves are added to directly cool flat wires, then cooling efficiency improves, but the winding structure becomes more complex
Solution Approach 1:
The cooling grooves are merged with the existing winding groove structure of the stator core. The same stator core that provides the magnetic circuit also incorporates the cooling channels, eliminating the need for separate cooling structures and reducing overall complexity.
Solution Approach 2:
The stator core serves multiple functions: it provides the magnetic circuit path, supports the flat wire windings, and acts as the cooling structure with integrated coolant channels. This multi-functionality reduces the number of separate components needed in the motor design.
3Stability of the object's composition
If the inner groove width of the cooling groove is made smaller than the flat wire width, then the flat wire is stabilized and prevented from falling, but the cooling channel space is reduced
Solution Approach 1:
The cooling groove width is optimized locally to provide just enough space for effective cooling while maintaining wire stability. The groove width varies in different sections to balance cooling efficiency with mechanical support functions, ensuring the flat wire remains positioned correctly without excessive groove dimensions.
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 direct cooling method effectively reduces heat loss, stabilizes the flat wires, and enhances the motor's performance and safety, prolonging the service life and improving power density.
Implementation Method 1
The first cooling groove is located on a side of the first flat wire in the radial direction of the motor stator, so that the coolant in the first cooling groove can dissipate heat for a radial surface of the first flat wire in the radial direction of the motor stator
Implementation Method 2
when the flat wire motor is in a working state, currents are centrally distributed on outer circumferential surfaces of the plurality of flat wires in each winding groove due to skin effect
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
This application provides a flat wire motor with a directly cooled flat wire winding, a powertrain, and an electric vehicle. A motor stator of the flat wire motor includes a plurality of winding grooves, and the plurality of winding grooves are spaced apart. The flat wire winding includes a plurality of connected flat wires, and each winding groove is configured to accommodate a plurality of flat wires. The plurality of flat wires include a first flat wire and a second flat wire, and the first flat wire and the second flat wire are arranged on two sides of other flat wires in the plurality of flat wires in a radial direction of the motor. One radial groove wall of the winding groove and the first flat wire are arranged adjacently in the radial direction of the motor, and a gap between the one radial groove wall and the first flat wire is used as a first cooling groove. The first cooling groove is configured to transmit coolant to directly cool the first flat wire, and in a circumferential direction of the motor, an inner groove width of the first cooling groove is less than a width of the first flat wire. In this application, the first cooling groove is formed by using the gap between the one radial side wall of the winding groove and the first flat wire, and the first cooling groove can cool and fasten the first flat wire. This helps improve cooling efficiency of the flat wire winding.