Magnetically Oriented Heat Conductive Material for Electrical Insulation

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Solution Overview

Problem

Existing heat conductive materials struggle to achieve both high heat conductivity and insulation properties, particularly in electronic equipment and batteries that generate heat under high voltage, often relying on materials with low insulation properties like metals.

Innovation Solution

A heat conductive material comprising a matrix resin and fillers with specific properties, including a first filler with high volume resistivity and low magnetic susceptibility, and a second filler with high magnetic susceptibility, oriented using a magnetic field during curing to enhance heat conductivity and insulation properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If a material with high conductivity (low insulation properties) such as metal is used as the heat radiating element, then heat conductivity is improved, but insulation properties deteriorate

Engineering Contradiction:
Improveheat conductivityVSAvoidinsulation properties
Core Design Contradiction:
TemperatureVSReliability

Solution Approach 1:

The patent uses a composite material consisting of a polymer matrix combined with boron nitride filler particles. This composite structure allows the material to simultaneously achieve high heat conductivity (through the boron nitride network) and excellent insulation properties (through the polymer matrix and high volume resistivity of boron nitride), resolving the contradiction between heat conduction and electrical insulation that plagues metal-based heat radiating elements

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent changes the physical and chemical parameters of the heat conductive material by controlling the volume resistivity of the filler to be 10^12 Ω·cm or more, and optimizing the filler content to 30-70 vol%. These parameter adjustments enable the material to achieve both high heat conductivity and superior insulation properties, overcoming the limitations of conventional metal-based solutions

Inventive Principle:
Principle #35Parameter changes

2Temperature

If heat conductive filler is oriented in constant direction in polymer, then heat conductivity is improved, but manufacturing complexity increases

Engineering Contradiction:
Improveheat conductivityVSAvoidmanufacturing process
Core Design Contradiction:
TemperatureVSEase of manufacture

Solution Approach 1:

The patent replaces complex mechanical orientation methods with a magnetic field application approach. By applying a magnetic field during the curing process, the boron nitride filler particles are automatically oriented in the thickness direction without requiring mechanical alignment equipment or complex processing steps, thus achieving high heat conductivity while maintaining ease of manufacture

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent utilizes the phase transition of the polymer matrix during curing (from liquid/resin state to solid state) as the magnetic field is applied. This timing allows the filler particles to be oriented by the magnetic field while the matrix is still in a workable state, and then locked in place upon curing, simplifying the overall manufacturing process while achieving the desired orientation

Inventive Principle:
Principle #36Phase transitions

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 material achieves both high heat conductivity and insulation properties, effectively managing heat radiation and electrical insulation in high-voltage applications, such as battery modules.

Implementation Method 1

a heat conductive compact configured by magnetic field orientation of boron nitride powder in constant direction in a polymer

Methodology Applied
Scientific EffectMagnetic field orientation: Magnetic Field

Data Source

PatentEP4465415A1Heat conductive material, method for producing heat conductive material, and battery module
Publication Date: 2024.11.20 TOYOTA JIDOSHA KK
  • EP4465415A1 patent drawingFigure 1A~2
  • EP4465415A1 patent drawingFigure 3A~4B
  • EP4465415A1 patent drawingFigure 5~6B

AI summary

A main object of the present disclosure is to provide a heat conductive material that achieves both heat conductivity and insulation properties. The present disclosure achieves the object by providing a heat conductive material including a matrix resin and a filler, wherein the filler includes a first filler that is a bar shape or a flake shape, and a second filler that is a bar shape or a flake shape; a volume resistivity of the first filler is 1012Ωcm or more; a magnetic susceptibility of the first filler is 10-6 or less; a magnetic susceptibility of the second filler is 10-5 or more; a content of the first filler is more than a content of the second filler; and in a cross-sectional view of the heat conductive material, when a filler X designates the filler of which angle of the longitudinal direction relative to a thickness direction of the heat conductive material is ±30° or less, a rate of the filler X with respect to all the filler is 30% or more.