Thermally Conductive Gap Filler Composition With Adhesion and Reworkability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current thermally conductive gap fillers for EV battery assemblies face challenges with high thermal conductivity, adhesion strength, toughness, damping performance, reworkability, pourability, and compatibility with various materials, while also posing safety concerns due to isocyanates and slow curing times, especially with silicone-based compositions.
Innovation Solution
A curable composition is developed, blending a polyol component, a functional butadiene component, aluminum tri-hydroxide (ATH), and a smoke suppressant like zinc hydroxy stannate, which achieves thermal conductivity of at least 3 W/mK, good adhesion, toughness, and reworkability without using polyurethane or silicone chemistries, and is compatible with diverse filler materials, including natural-based raw materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a large amount of inorganic thermally conductive filler is added to achieve high thermal conductivity, then thermal conductivity is improved, but adhesion performance, toughness, damping performance, viscosity, and density are degraded
Solution Approach 1:
The patent employs a composite material system combining organic fillers (graphite, carbon nanotubes, graphene) with inorganic fillers (alumina, aluminum trihydrate). This hybrid approach leverages the high thermal conductivity of inorganic fillers while the organic fillers maintain matrix continuity, preserving adhesion and toughness. The organic fillers act as spacers and bonding agents, preventing excessive filler aggregation and maintaining polymer chain mobility for adhesion.
Solution Approach 2:
The patent changes the chemical composition parameters of the filler system by introducing oxygen-containing functional groups on graphite surfaces and using surface-modified fillers. This chemical modification improves interfacial bonding between fillers and the polymer matrix, thereby maintaining adhesion performance even at high filler loadings. The parameter change from pure inorganic to functionalized hybrid fillers resolves the adhesion contradiction.
2Temperature
If polyurethane-based materials are used at high filler loadings to achieve beneficial properties, then thermal conductivity and adhesion are improved, but stability at elevated temperatures deteriorates and safety concerns arise due to isocyanates
Solution Approach 1:
The patent extracts and eliminates the problematic isocyanate component from the polyurethane system, replacing it with alternative curing chemistries such as epoxy-amine, epoxy-thiol, or polyhydric alcohol systems. This extraction removes the safety hazards and thermal instability associated with isocyanates while maintaining the structural integrity and thermal conductivity benefits of high filler loading compositions.
Solution Approach 2:
The patent changes the chemical composition parameters by selecting alternative polymer matrices and curing agents with inherently better thermal stability. The use of epoxy resins, polyester polymers, or polyether polymers instead of polyurethane chemistry provides superior high-temperature stability and eliminates isocyanate-related safety issues while preserving the desired mechanical and thermal properties.
3Temperature
If silicone-based compositions are used to achieve thermal conductivity, then thermal performance is improved, but curing time increases and compatibility with battery components deteriorates
Solution Approach 1:
The patent changes the chemical composition parameters by selecting fast-curing polymer systems such as epoxy-amine or epoxy-thiol chemistries that can achieve full cure within hours rather than days. These alternative chemistries provide comparable or superior thermal conductivity to silicone-based materials while dramatically reducing curing time and improving compatibility with battery components like foams, polyesters, and aluminum through controlled adhesion properties.
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 provides a balanced set of properties including high thermal conductivity, strong adhesion, reworkability, and compatibility with various materials, while maintaining low viscosity and density, and achieving UL-94 V0 flame retardancy, thus addressing the limitations of existing gap fillers.
Implementation Method 1
a filler that includes aluminum tri-hydroxide (ATH) and a smoke suppressant... The curable composition has, upon curing, a thermal conductivity of at least 3.0 W/(mK)
Implementation Method 2
A curable composition is developed, blending a polyol component, a functional butadiene component... The cured composition is the reaction product of the curable composition
Data Source
AI summary
A curable composition includes a polyol component including one or more polyols; a functional butadiene component; and filler particles; wherein the curable composition has, upon curing, a thermal conductivity of at least 3.0 W/(mK). The filler particles include aluminum trihydrate (ATH) and a smoke suppressant selected from zinc hydroxy stannate (ZHS), zinc stannate, calcium stannate, calcium hydroxy stannate and any combination thereof.