PCM Wax Mixture Cooling Casing for EV Motor Temperature Transients

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Solution Overview

Problem

High-performance electric vehicles require effective temperature regulation to manage rapid temperature transients, but existing cooling systems, especially those using liquid cooling, are inefficient and prone to issues like size, safety, and emissions, and traditional PCM waxes have limitations such as low heat conductivity and viscosity problems, especially when used in electric motors with varying operational temperatures.

Innovation Solution

A composition of at least two PCM waxes with different melting temperatures, ranging from 60 to 120 °C, is used to accumulate latent heat within a hollow cooling casing, allowing for efficient temperature control and stability across a broad range, reducing the need for traditional liquid cooling systems and minimizing material degradation over cycles.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If traditional liquid cooling systems are used for electric machines, then cooling function is provided, but the system size increases, safety issues arise, and consumption/emissions problems occur

Engineering Contradiction:
Improvetemperature regulationVSAvoidcooling system complexity
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

The invention extracts the cooling function from complex liquid cooling systems with pumps, channels, and refrigerants, and implements it using a simple PCM-based passive cooling system that relies on phase change material properties alone, eliminating the need for complex mechanical components

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The PCM cooling system is self-regulating through the natural phase change process of the material, which automatically absorbs heat during melting without requiring external control systems, pumps, or active management, making the system self-service and highly reliable

Inventive Principle:
Principle #25Self-service

2Use of energy by moving object

If single PCM wax is used for heat accumulation, then latent heat storage is achieved, but the temperature range coverage is limited and performance degrades after multiple cycles

Engineering Contradiction:
Improvelatent heat storageVSAvoidtemperature range coverage
Core Design Contradiction:
Use of energy by moving objectVSStability of the object's composition

Solution Approach 1:

The invention uses composite materials by combining multiple PCM waxes with different melting points into a single cooling composition, creating a multi-component system that covers a broader temperature range (60-120°C) while maintaining stable performance over multiple thermal cycles

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The invention changes the physical parameters of the cooling system by selecting waxes with specific melting points (e.g., C20-C30 range around 60-75°C, C30-C40 range around 76-85°C, C40-C50 range around 86-102°C) to optimize the temperature coverage and match the operational temperature profile of electric machines

Inventive Principle:
Principle #35Parameter changes

3Power

If high-performance electric motors are used, then vehicle performance increases, but temperature transients become more rapid and irregular, requiring more effective cooling

Engineering Contradiction:
Improvemotor performanceVSAvoidtemperature transient regulation
Core Design Contradiction:
PowerVSTemperature

Solution Approach 1:

The invention optimizes the thermal response parameters by carefully selecting the composition and proportions of different waxes to match the rapid and irregular temperature transients characteristic of high-performance electric motors, ensuring effective cooling across varying operational conditions

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The multi-wax composite composition provides enhanced thermal management capability for high-power motors by combining materials with different phase change temperatures, creating a progressive cooling effect that handles both rapid transients and sustained thermal loads

Inventive Principle:
Principle #40Composite materials

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 PCM wax mixture effectively manages temperature transients in electric vehicle motors by maintaining a stable temperature range, optimizing performance and reducing the risk of material breakdown, even after multiple cycles, while providing a cost-effective and compact cooling solution.

Implementation Method 1

Latent heat storage is based on the heat absorbed or released when a material undergoes a phase change from solid to liquid or from liquid to gas (and vice versa), without significant changes in temperature

Methodology Applied
Scientific EffectPhase change: Phase Change

Implementation Method 2

a composition comprising a mixture of at least two waxes belonging to the class of phase change materials (PCM waxes) as an element for accumulating latent heat

Methodology Applied
Scientific EffectLatent heat: Latent Heat

Data Source

PatentEP4004140B1Mixture of PCM waxes as an element for accumulating latent heat in electric machines
Publication Date: 2024.07.17 ELDOR CORP SPA
  • EP4004140B1 patent drawingFigure 1~2
  • EP4004140B1 patent drawingFigure 3
  • EP4004140B1 patent drawingFigure 4

AI summary

The present invention relates to the use of a composition comprising a mixture of at least two waxes belonging to the class of phase change materials (PCMs) as an element for accumulating latent heat in an electric machine, preferably for automotive use. In one embodiment, the composition is contained inside a hollow cooling casing of an electric machine, preferably for automotive use. The present invention also relates to a method for producing a hollow cooling casing containing said composition and for cooling an electric machine which comprises the use of said cooling casing.