Graphite Thermal Management via SiC Inserts
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Solution Overview
Problem
Conventional graphite sheet heat spreaders in small electronic devices face challenges with thermal conductivity in the z-direction, leading to hot spots and reduced heat transport efficiency due to the low thermal conductivity through the thickness, which is exacerbated by the use of adhesives that act as thermal resistors, limiting the ability to effectively manage heat in compact designs with high component density.
Innovation Solution
A thermal management system is developed that incorporates a graphite sheet with regions of varying thickness to create directed heat paths, including a transverse heat path using thermal inserts made of materials like silicon carbide (SiC) that are bonded to the graphite sheet, allowing for enhanced heat transfer in the z-direction and providing additional heat sinks by directing heat out-of-plane.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional adhesives are used to bond heat spreader layers, then structural integrity is maintained, but thermal resistance increases due to low thermal conductivity
Solution Approach 1:
The patent changes the thermal conductivity parameter of the adhesive material from conventional low values to enhanced values (5-10 W/m-K). This parameter change allows the adhesive to maintain its bonding function while simultaneously providing improved thermal transport, eliminating the trade-off between structural integrity and thermal performance.
Solution Approach 2:
The thermally conductive adhesive serves as an intermediary material that fulfills both mechanical bonding and thermal transport functions. Rather than using separate adhesive and thermal interface materials, the adhesive itself acts as the thermal pathway, mediating between structural requirements and thermal performance needs.
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
This approach significantly improves heat management in small form factor devices by creating orthogonal heat paths that increase thermal conductivity and reduce thermal resistance, enabling more efficient heat dissipation and reducing the risk of hot spots, while maintaining structural integrity and compatibility with graphite.
Implementation Method 1
graphite sheet material exhibits a high thermal conductivity in the plane (x,y) of the graphite sheet... the graphite sheet can have a thermal conductivity ranging from about 1200-1500 W/m-K (depending upon the thickness) in a direction that is generally parallel to the layer planes (x,y)
Implementation Method 2
an interfacial layer formed of a thermally insulating adhesive material disposed between the first and second layers
Implementation Method 3
The interfacial layer includes a thermal via that allows heat to flow between the first and second layers along a defined path
Data Source
AI summary
A thermal management system is described. The thermal management system being well suited for electronic devices having limited size and operational components that produce excess heat. The thermal management system includes a thermal transport mechanism formed of material having anisotropic thermal conducting properties such that heat is transported from a heat source to a heat sink using a directed heat path. The directed heat path provided by regions having a first thermal conductivity embedded within a substrate characterized as having a second thermal conductivity that is less than the first thermal conductivity.