Thermally Conductive Silicone Composition for Stable Gap Filling
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Solution Overview
Problem
The existing thermally conductive compositions used for filling gaps between heating elements and heat sinks have inconsistent curing rates, leading to issues with workability and product reliability due to variations in ambient temperature, which can cause misalignment and deformation during assembly.
Innovation Solution
A thermally conductive composition comprising organopolysiloxane, hydrogenorganopolysiloxane, thermally conductive filler, and a reaction rate controlling agent, with specific viscosity and storage modulus ranges to maintain fluidity and stiffness over a wide temperature range, ensuring good workability and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the thermally conductive composition is slow to cure, then fluidity is maintained for alignment, but gaps may be created and misalignment occurs between heating element and heat sink
Solution Approach 1:
The patent applies parameter changes by carefully controlling the curing reaction kinetics through catalyst selection and concentration optimization. The curing rate is adjusted to achieve a specific viscosity profile that maintains fluidity for alignment while progressively developing stiffness to prevent gaps and misalignment, resolving the contradiction between reliability and productivity.
Solution Approach 2:
The patent implements dynamics by creating a time-dependent viscosity profile where the composition transitions from a fluid state (maintaining alignment) to a progressively stiffening state (preventing gaps). This dynamic rheological behavior ensures both alignment stability and curing efficiency are achieved at different stages of the curing process.
2Reliability
If the thermally conductive composition is fast to cure, then alignment stability is improved, but workability deteriorates due to shortened softness maintenance time and large compression load
Solution Approach 1:
The patent uses parameter changes to optimize the curing kinetics, controlling the rate at which the composition transitions from soft to stiff. By adjusting catalyst concentration and type, the composition maintains adequate softness for workability (compression and positioning) while progressively achieving alignment stability, avoiding both premature stiffening and excessive softness duration.
3Adaptability or versatility
If the curing rate varies with ambient temperature, then seasonal adaptability is reduced, but different problems occur in summer (deteriorated workability) and winter (misalignment and reduced reliability)
Solution Approach 1:
The patent applies parameter changes by selecting catalyst systems and composition formulations whose curing kinetics are relatively insensitive to ambient temperature variations. This ensures consistent curing behavior and reliable performance across different seasonal conditions, achieving both adaptability and consistent reliability.
Solution Approach 2:
The patent uses composite materials by combining multiple components (base resin, curing agent, catalyst, fillers) in specific proportions to create a thermally conductive composition with optimized curing characteristics. This composite formulation ensures stable curing rate and consistent performance across a wide temperature range, resolving the contradiction between adaptability and reliability.
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 achieves stable viscosity and curing properties, maintaining workability in summer and reliability in winter, preventing misalignment and deformation, and ensuring efficient heat transfer in battery modules.
Implementation Method 1
a cured product formed by filling a curable thermally conductive composition between a heating element and a heat sink and then curing it
Implementation Method 2
the rate of a curing reaction can be controlled by adjusting combination of a catalyst or a reaction retardant
Implementation Method 3
a thermally conductive member that transfers heat generated from the heating element to the heat sink
Data Source
AI summary
The present invention provides a thermally conductive composition comprising (A) an organopolysiloxane containing at least two alkenyl groups, (B) a hydrogenorganopolysiloxane containing at least two hydrosilyl groups, (C) a thermally conductive filler, and (D) a reaction rate controlling agent, wherein in measurement using a viscoelasticity measuring apparatus under conditions of 35° C., a shear mode, a frequency of 1 Hz, and a strain of 10%, a storage modulus G′1 after 3,600 seconds from the start of the measurement is 2,000 Pa or less, and a storage modulus G′2 after 7,200 seconds from the start of the measurement is 4,350 Pa or more, and wherein viscosity measured at 25° C. and a shear rate of 10 rpm is 220 Pa·s or less. According to the present invention, it is possible to provide the thermally conductive composition that has good workability and maintains reliability as a product, over a relatively wide temperature range.