Printed Copper Paste Wick for High-Porosity Thin Heat Pipes
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Solution Overview
Problem
Conventional methods struggle to form wicks with high porosity and complex shapes in thin-film or flat plate-shaped heat pipes, particularly due to the limitations of using copper powder sintering, which results in reduced porosity and increased flow resistance.
Innovation Solution
A copper paste containing copper particles, thermally decomposable resin particles, and a dispersion medium is used, where the thermally decomposable resin particles create pores during sintering, allowing for the formation of wicks with high porosity and complex shapes by printing and sintering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional copper powder sintering method is used, then the wick can be formed with simple process, but the porosity is reduced and flow resistance increases
Solution Approach 1:
The invention uses porous spherical copper particles as the base material, which inherently possess a porous structure. This allows the wick to maintain high porosity (40-70%) after sintering, enabling efficient liquid transport while keeping the manufacturing process relatively simple. The porous structure of the starting material directly translates to the final product's porosity, resolving the contradiction between ease of manufacture and porosity.
Solution Approach 2:
The invention creates a composite structure by combining porous spherical copper particles with copper powder. The porous spherical particles provide the necessary porosity and capillary channels, while the copper powder fills gaps and provides structural support. This composite approach allows the wick to achieve both high porosity and mechanical strength without complicating the manufacturing process excessively.
2Ease of manufacture
If copper powder sintering is used, then the wick formation is straightforward, but the pore size is reduced and flow resistance increases
Solution Approach 1:
By using porous spherical copper particles with controlled pore sizes (1-10 μm) instead of conventional copper powder, the invention creates larger capillary channels that reduce flow resistance. The porous structure provides well-defined pore pathways that facilitate efficient liquid transport, directly improving heat transport efficiency while maintaining straightforward sintering fabrication.
Solution Approach 2:
The invention applies different material characteristics to different regions of the wick structure. The porous spherical particles provide localized porosity and capillary channels in specific regions, while the overall wick structure maintains structural integrity. This local differentiation of material properties enables efficient liquid transport without compromising the overall wick formation process.
3Volume of moving object
If thin-film wicks are formed to reduce heat pipe thickness, then the volume is reduced, but the porosity and pore size are compromised
Solution Approach 1:
The use of porous spherical copper particles with predetermined pore structures allows the formation of thin-film wicks that maintain high porosity. The spherical particles can be arranged and sintered into thin layers while preserving their internal porous structure, enabling thin heat pipes (reduced volume) without sacrificing the porosity needed for liquid transport.
Solution Approach 2:
The invention transitions from considering only the two-dimensional plane of the wick to incorporating the third dimension of particle internal structure. The porous spherical particles provide porosity in their internal volume, allowing thin-film wicks to achieve high porosity not just through thickness but through the three-dimensional porous structure of the constituent particles.
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 copper paste enables the formation of thin-film wicks with high porosity and suitable pore sizes, reducing flow resistance and enhancing the performance of heat pipes in small-sized devices.
Implementation Method 1
thermally decomposable resin particles, a dispersion medium for dispersing the copper particles and the thermally decomposable resin particles, and a thermally decomposable resin that is soluble in the dispersion medium
Implementation Method 2
subsequently compressing the metal powder under pressure, and firing the metal powder to be sintered
Implementation Method 3
a member called a 'wick' that produces a capillary pumping action
Data Source
AI summary
A copper paste for forming a wick of a heat pipe contains copper particles, thermally decomposable resin particles, a dispersion medium for dispersing the copper particles and the thermally decomposable resin particles, and a thermally decomposable resin that is soluble in the dispersion medium. A method for forming a wick of a heat pipe comprises a step of printing the copper paste and a step of sintering the copper paste. A heat pipe comprises a wick including a sintered body of the copper paste.