Stacked Stator Laminations With Coolant Channels for Motor Heat Control

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Electrical machines, such as electric motors, face various losses including resistive, hysteresis, and thermal losses, which can lead to increased resistance and potential damage from elevated operating temperatures, necessitating effective cooling solutions to manage thermal constraints.

Innovation Solution

A stator stack design featuring stacked laminations with projecting mounting lobes and indentations that form coolant flow channels, allowing an oil-dispersing coolant to flow along the circumference for enhanced cooling, with the dimensions of these channels adjustable based on desired flow rates and thermal constraints.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If conventional stator design without integrated coolant channels is used, then manufacturing process is simpler, but cooling effectiveness is insufficient leading to elevated operating temperatures

Engineering Contradiction:

Improvemaximum operating temperatureVSAvoidstator structure complexity

Core Design Contradiction:

TemperatureVSDevice complexity

Solution Approach 1:

The stator core is segmented into multiple laminations, each with cooling indentations, allowing coolant flow paths to be distributed throughout the stack. This segmentation enables effective cooling without requiring a completely redesigned monolithic structure.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The cooling function is merged with the structural lamination design by integrating coolant flow channels directly into the stator laminations themselves. This eliminates the need for separate cooling systems and reduces overall device complexity despite adding cooling capability.

Inventive Principle:

Principle #5Merging (Combining)

2Reliability

If coolant flow channels are added to stator laminations, then cooling effectiveness improves, but manufacturing complexity increases

Engineering Contradiction:

Improvethermal management reliabilityVSAvoidlamination manufacturing ease

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

Coolant flow channels are formed as indentations during the lamination manufacturing process itself, before assembly. This preliminary action integrates cooling feature creation into the existing manufacturing workflow, minimizing additional manufacturing complexity.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The lamination structure itself provides the cooling function through integrated indentations that guide coolant flow. The stator core serves its own cooling needs through this self-contained design, eliminating dependence on external cooling systems.

Inventive Principle:

Principle #25Self-service

3Productivity

If stacked laminations are rotated 90 degrees relative to each other, then coolant flow distribution improves, but assembly precision requirements increase

Engineering Contradiction:

Improvecoolant flow efficiencyVSAvoidlamination stacking precision

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

Laminations are designed with asymmetric cooling indentations that create a predetermined rotation pattern (90 degrees) when stacked. This asymmetric design guides the assembly process and ensures proper orientation without requiring complex alignment procedures.

Inventive Principle:

Principle #4Asymmetry

Solution Approach 2:

Different regions of the stator stack have locally optimized cooling channel orientations. The 90-degree rotation creates varied local flow paths that collectively improve overall coolant distribution and thermal management efficiency.

Inventive Principle:

Principle #3Local quality

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 effectively reduces the maximum operating temperature of the electric motor drive unit, increasing its reliability and operational lifespan by preventing thermal damage like magnet derating or stator winding enamel strength reduction.

Implementation Method 1

an oil-dispersing coolant dispersed to the stator stack may be allowed to pervade each of the mounting lobes of each lamination and flow along the circumference of the stator stack for more effectively cooling the stator stack

Methodology Applied

Scientific EffectConvection: Convection

Data Source

PatentEP4280427A1Stator core of stacked laminations with coolant flow channels

Publication Date: 2023.11.22 RIVIAN HOLDINGS LLC

Figure 1
Figure 2A
Figure 2B

AI summary

A stator assembly includes a plurality of laminations configured to form a stator stack. Each of the plurality of laminations includes a set of projections disposed along an outer perimeter of the lamination, in which each of the set of projections includes a mounting hole passing therethrough. Each of the plurality of laminations further includes a plurality of indentations each extending into a respective one of the set of projections. The plurality of laminations are configured to form the stator stack in accordance with a predetermined indexing, such that the plurality of indentations define one or more coolant flow channels.