Thermally Conductive Gap Filler Composition With Strong Adhesion

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Solution Overview

Problem

Current thermally conductive gap fillers for EV battery assemblies face challenges with high thermal conductivity being compromised by poor adhesion, toughness, damping performance, and viscosity issues, along with safety concerns from isocyanates in polyurethane-based materials and incompatibility with certain components, such as foams and aluminum, in silicone-based compositions.

Innovation Solution

A curable composition comprising a polyol component, a functional butadiene component, and a thermally conductive filler, with the filler present at least 20 wt.%, providing a balance of thermal conductivity, adhesion strength, toughness, and reworkability, and compatibility with various filler materials, without relying on polyurethane or silicone chemistries, and using natural/plant-based raw materials.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If high loading of thermally conductive fillers is used to achieve high thermal conductivity, then thermal conductivity is improved, but adhesion performance, toughness, damping performance, and viscosity deteriorate

Engineering Contradiction:

Improvethermal conductivityVSAvoidadhesion performance

Core Design Contradiction:

TemperatureVSStrength

Solution Approach 1:

The patent uses a composite material system combining polyol, functional butadiene, and thermally conductive filler to achieve both high thermal conductivity and good adhesion. The functional butadiene component acts as a coupling agent that bridges the filler particles and the polyol matrix, ensuring strong interfacial adhesion even at high filler loadings (≥20 wt.%). This composite approach allows simultaneous optimization of thermal conductivity and mechanical properties.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent optimizes the chemical structure and functional groups of the butadiene component to enhance its compatibility with both the polyol and filler materials. By adjusting the functionalization degree and molecular weight of the butadiene, the formulation achieves balanced rheological properties and adhesion performance across a wide range of filler concentrations, resolving the trade-off between thermal conductivity and mechanical properties.

Inventive Principle:

Principle #35Parameter changes

2Temperature

If polyurethane-based materials are used for thermal conductivity, then thermal performance is improved, but safety concerns arise due to isocyanates

Engineering Contradiction:

Improvethermal conductivityVSAvoidsafety concerns from isocyanates

Core Design Contradiction:

TemperatureVSObject-affected harmful factors

Solution Approach 1:

The patent extracts and eliminates the harmful isocyanate component from the polyurethane system while retaining the desirable thermal conductivity and adhesion properties. The formulation replaces isocyanate-based crosslinking with alternative chemistry using functional butadiene and polyol, removing the safety hazard associated with isocyanates while maintaining performance through careful selection of functional groups and curing mechanisms.

Inventive Principle:

Principle #2Taking out (Extraction)

3Temperature

If silicone-based compositions are used for thermal conductivity, then thermal performance is improved, but incompatibility with certain components such as foams and aluminum occurs

Engineering Contradiction:

Improvethermal conductivityVSAvoidcompatibility with foams and aluminum

Core Design Contradiction:

TemperatureVSAdaptability or versatility

Solution Approach 1:

The patent designs the functional butadiene component to provide universal compatibility across diverse substrates including foams, aluminum, and other battery assembly components. The functional groups in the butadiene are selected to form favorable interactions with multiple material types, creating a universally compatible adhesive system that works across the entire battery assembly ecosystem without causing degradation or incompatibility issues.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 curable composition achieves tunable thermal conductivity, strong adhesion, and reworkability while being compatible with a broad range of filler materials, enhancing the performance and safety of EV battery assemblies.

Implementation Method 1

a thermally conductive filler, the thermally conductive filler being present in an amount of at least 20 wt. %, based on the total weight of the curable composition; wherein the curable composition has, upon curing, a thermal conductivity of at least 0.5 W/(mK)

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentUS12199255B2Curable compositions comprising polyol component, functional butadiene component, and thermally conductive filler, articles therefrom, and methods of making and using same

Publication Date: 2025.01.14 3M INNOVATIVE PROPERTIES CO

AI summary

A curable composition includes a polyol component comprising one or more polyols: a functional butadiene component; and a thermally conductive filler. The thermally conductive filler is present in an amount of at least 20 wt. %, based on the total weight of the curable composition. The curable composition has, upon curing, a thermal conductivity of at least 0.5 W/(mK).