Two-Component Thermally Debondable Epoxy Adhesive for E-Mobility

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Solution Overview

Problem

Existing adhesive compositions used in e-mobility components are difficult to debond without damaging the substrates, especially in applications requiring disassembly, such as automotive battery cells, due to their strong adhesion and sensitivity to mechanical or chemical removal methods.

Innovation Solution

A thermally debondable two-component epoxy adhesive composition comprising an epoxy resin, reactive diluent, thermally expandable thermoplastic microspheres, and curing agents, which can be mixed in a specific ratio to provide effective debonding at controlled temperatures without damaging the substrates.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If strong adhesion is used to maintain bond strength during drop or impact events and across wide operating temperatures, then reliability is improved, but ease of disassembly deteriorates

Engineering Contradiction:

Improveadhesion strengthVSAvoidease of disassembly

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The adhesive composition changes its properties through temperature variation. At operating temperatures, the adhesive maintains strong adhesion through its crosslinked epoxy network. During disassembly, heating to elevated temperatures (e.g., 150-200°C) causes the adhesive to soften and lose strength, enabling easy separation. This parameter change allows the same material to satisfy both strong bonding during use and easy disassembly when needed.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The adhesive system transitions from a static strong-bond state during normal operation to a dynamic debonding state when heated. The thermally reversible behavior allows the adhesive to dynamically adjust its bonding characteristics based on temperature conditions, providing strong adhesion when cool and easy release when hot, thus resolving the contradiction between reliable bonding and ease of disassembly.

Inventive Principle:

Principle #15Dynamics

2Ease of operation

If mechanical processes like sand blasting or wire brushing are used to remove adhesive, then debonding capability is improved, but substrate damage increases

Engineering Contradiction:

Improvedebonding capabilityVSAvoidsubstrate damage

Core Design Contradiction:

Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The invention replaces mechanical removal processes (sand blasting, wire brushing) with a thermal process. By heating the adhesive to elevated temperatures, the material softens and loses adhesion strength, allowing substrates to be separated without mechanical contact that could cause damage. This substitution of thermal action for mechanical action eliminates substrate damage while achieving effective debonding.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Ease of operation

If aggressive chemicals or high temperature are applied to debond adhesive, then debonding effectiveness is improved, but substrate integrity deteriorates

Engineering Contradiction:

Improvedebonding effectivenessVSAvoidsubstrate damage

Core Design Contradiction:

Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The adhesive is formulated to undergo a controlled parameter change at specific temperature ranges. When heated to the debonding temperature window (e.g., 150-200°C), the adhesive softens and loses strength, enabling effective separation. This controlled thermal response allows debonding without requiring aggressive chemicals or excessive temperatures that could damage substrates, thus achieving effective debonding while preserving substrate integrity.

Inventive Principle:

Principle #35Parameter changes

4Ease of operation

If high temperature is applied to disrupt bonding at the adhesive-substrate interface, then debonding capability is improved, but substrate damage increases

Engineering Contradiction:

Improvedebonding capabilityVSAvoidsubstrate damage

Core Design Contradiction:

Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The adhesive composition is designed to undergo a controlled softening transition at specific temperature ranges. When heated to the debonding temperature window, the adhesive's mechanical properties change, causing it to soften and lose adhesion strength. This controlled thermal response enables effective debonding while limiting the temperature exposure time and magnitude, thereby preventing substrate damage that would occur with uncontrolled high-temperature exposure.

Inventive Principle:

Principle #35Parameter changes

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 composition offers optimized adhesion on various substrates, easy debonding with reduced bond strength after heat activation, and provides thermal isolation, protecting the substrates during debonding.

Implementation Method 1

thermally expandable thermoplastic microspheres

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 2

applying a heat; and, ii) debonding the surfaces

Methodology Applied

Scientific EffectHeating: Heating

Data Source

PatentEP4631987A1A thermally debondable two-component epoxy adhesive composition

Publication Date: 2025.10.15 HENKEL KGAA

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AI summary

The present invention relates to use a thermally debondable two-component epoxy adhesive composition, or cured product according to the present invention in a bonded structure, wherein the bonded structures are for example e-mobility related components.