Dual Liquid Cooling Electric Motor Gap Thermal Management
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In liquid-cooled electric motors, gaps or voids in the thermally conductive compound between the stator and sleeve reduce thermal conduction efficiency, leading to overheated stator windings and reduced reliability.
Innovation Solution
A dual cooling medium system is implemented, where a first electrically conductive liquid coolant flows through the gap between the stator and rotor, and a second dielectric or phase-change coolant fills voids between the sleeve and stator, enhancing thermal conduction and natural convective cooling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a thermally conductive compound is used between the sleeve and stator, then thermal conduction is improved, but voids in the compound reduce thermal conduction efficiency
Solution Approach 1:
The second cooling medium acts as an intermediary substance that fills the voids between the sleeve and stator, replacing air (poor thermal conductor) with a fluid that provides both thermal conduction and convective cooling capabilities, thereby resolving the thermal conduction efficiency problem caused by voids
Solution Approach 2:
The system utilizes phase-change material as the second cooling medium, which absorbs heat during phase transition (solid to liquid), providing enhanced thermal management and preventing overheating of the stator windings
2Temperature
If a single cooling medium is used, then system simplicity is maintained, but heat transfer efficiency is insufficient
Solution Approach 1:
The cooling system is segmented into two distinct zones: the first cooling medium flows through the rotor cavity, while the second cooling medium fills the stator-sleeve interface voids. This segmentation allows each cooling medium to perform its specialized function optimally
Solution Approach 2:
Different cooling media are applied to different locations based on specific thermal requirements: the first cooling medium addresses rotor cooling needs, while the second cooling medium specifically targets the heat transfer interface between stator and sleeve where voids exist
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 dual cooling mechanism improves heat transfer efficiency, reducing overheating and increasing operational reliability by eliminating air gaps and simplifying the manufacturing process through a press-fit assembly.
Implementation Method 1
Heat from the stator winding is conducted from the stator through the sleeve and finally to the cooling medium within the sleeve and surrounding the rotor
Implementation Method 2
Heat produced by the stator creates a natural convective flow within the second coolant contained in the second cavity
Implementation Method 3
an interface between the stator and the sleeve comprises a press fit and any voids between the sleeve and stator are filled with the second cooling medium
Data Source
Figure 1
Figure 2~4
Figure 5
AI summary
An electric machine (10) includes a rotor (12) within a cavity defined within a stator (18). A liquid coolant (24) is utilized to cool the stator and rotor. The liquid coolant flows through a gap (26) defined between the stator and the rotor. A second coolant (38) is provided that is contained within a second cavity (36) disposed annularly about the first cavity. Thermal energy is transferred away from the gap (26) by way of the first coolant (24) flowing through the gap and by natural convection of the second liquid coolant (38) within the second cavity. The additional mechanism for transferring heat enhances electric machine operation and provides increased operational capacities.