Graphite Plate Porosity Control for Heat Release
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Solution Overview
Problem
Conventional highly-oriented graphite sheets used for heat release in mobile devices suffer from reduced heat conductivity due to gas-filled pores and lack of flexibility, which limits their effectiveness and durability as thin heat-releasing members.
Innovation Solution
A graphite plate with porosity ranging from 1% to 30% is produced by applying welding pressure to glass-like carbon materials in an inert atmosphere, achieving high heat conductivity and flexibility through controlled heat treatment and molding processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional highly-oriented graphite sheets are used for heat release, then heat conductivity is improved, but porosity increases causing heat insulation properties
Solution Approach 1:
The patent changes the porosity parameter from conventional high levels (causing heat insulation) to a controlled range of 1-30%, and controls the pore size to 1-100 μm. This parameter optimization allows the graphite plate to maintain high heat conductivity (100-1500 W/m·K) while eliminating the harmful heat insulation effect of excessive porosity.
Solution Approach 2:
The patent creates a differentiated pore structure where pores are distributed throughout the graphite plate but with controlled size (1-100 μm) and density (1-30% porosity). This local quality control ensures that pores do not form continuous insulating paths while still providing the desired flexibility and structural properties.
2Length of stationary object
If graphite sheets are made thinner to achieve device thinning, then device thickness is reduced, but heat transport capability deteriorates
Solution Approach 1:
The patent optimizes the thickness parameter of the graphite plate to balance device thinning requirements with heat transport capability. By controlling porosity (1-30%) and pore size (1-100 μm) alongside thickness, the patent achieves high heat conductivity (100-1500 W/m·K) in thin plates, enabling effective heat transport without compromising device thinning goals.
3Reliability
If conventional graphite sheets are used, then heat release function is provided, but flexibility is lost due to pore formation
Solution Approach 1:
The patent controls porosity within 1-30% and pore size within 1-100 μm to maintain flexibility while providing heat release function. This optimized pore structure prevents excessive rigidity that would result from high porosity, allowing the graphite plate to conform to device surfaces and components effectively.
4Length of stationary object
If heat pipes are thinned to reduce device thickness, then device thinning is achieved, but liquid circulation stops and heat transport equals mere conduction
Solution Approach 1:
The patent transitions from heat pipe technology (relying on liquid circulation) to a graphite plate with optimized porosity (1-30%) and pore size (1-100 μm). This parameter change enables the graphite plate to achieve high heat conductivity (100-1500 W/m·K) through solid-state conduction without requiring liquid circulation, making it suitable for thin applications where heat pipes cannot be effectively thinned.
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 resulting graphite plate exhibits high heat conductivity (up to 1500 W/m·K) and flexibility, making it suitable for use as a heat-releasing member in electronic devices without the drawbacks of porosity and inflexibility in conventional materials.
Implementation Method 1
the heat conductivity of graphite itself is about 1500 W/m·K, and thus, is very high
Implementation Method 2
Such highly-oriented graphite sheets have been produced by heating polymer films to around 300° C.
Implementation Method 3
oxygen, nitrogen and hydrogen gases that have been produced during the high-temperature heat treatment remain in the sheets in the form of bubbles
Data Source
AI summary
Provided is a graphite plate, consisting essentially of: graphite; and pores, wherein said graphite plate has a porosity from 1% to 30%. Further provided is a method for producing a graphite plate, including: applying welding pressure to at least one glass-like carbon material in a state in which said at least one glass-like carbon material is maintained in an inert atmosphere under heating conditions, to produce a graphite plate having a porosity from 1% to 30%.