Liquid Cold Welding of Porous Metal Layers Without High-Temperature Bonding
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Solution Overview
Problem
Existing methods for producing porous 3D metal structures face challenges in scalability and cost-effectiveness, particularly when dealing with substrates larger than typical silicon wafers, and require high temperatures for bonding.
Innovation Solution
The use of liquid cold welding (LCW) method involving electrochemical bonding of porous conductive substrate layers in an electrolyte solution with controlled application of electric current, voltage, or power, facilitated by perforated non-conductive frames and electrodes, allows for cost-effective and scalable production of porous 3D metal structures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If high temperature is used for layer bonding, then bonding strength is improved, but energy consumption and manufacturing complexity increase
Solution Approach 1:
The invention changes the bonding parameter from high temperature thermal bonding to low temperature electrochemical bonding. By applying electric current through the electrolyte solution, metal ions are reduced and deposited at the contact interfaces between substrate layers, creating strong metallurgical bonds without requiring high temperature heating, thus resolving the contradiction between bonding strength and energy consumption
Solution Approach 2:
The invention replaces the thermal field (heat) with an electrochemical field (electric current). Instead of using thermal energy to activate atomic diffusion for bonding, the patent uses electrochemical reactions where metal ions from the electrolyte are reduced at the cathode surfaces, forming metallurgical bonds at room or low temperatures, thereby substituting a high-energy thermal process with a low-energy electrochemical process
2Manufacturing precision
If photoresist patterning and electrodeposition are used for high resolution porous structures, then manufacturing precision is improved, but device complexity and production cost increase
Solution Approach 1:
The invention extracts and eliminates the complex photoresist patterning steps from the fabrication process. By using pre-formed porous substrate layers with predetermined patterns and structures, the patent removes the need for repetitive patterning, electroplating, pattern dissolution, and metal dissolving steps, significantly simplifying the manufacturing process while maintaining high resolution and precision of the porous structures
Solution Approach 2:
The invention performs the complex structure formation in advance by using pre-manufactured porous substrate layers with controlled porosity, pore shapes, and sizes. These pre-prepared layers are then simply stacked and bonded together, eliminating the need for complex in-process patterning and structure formation steps, thereby reducing device complexity while preserving manufacturing precision
3Manufacturing precision
If repetitive electroplating and pattern dissolution steps are used, then porosity control is improved, but productivity decreases
Solution Approach 1:
The invention merges multiple repetitive fabrication steps into a single bonding operation. By stacking pre-formed porous layers and bonding them together in one electrochemical process, the patent eliminates the need for repeated electroplating, patterning, and dissolution cycles, thereby maintaining precise porosity control through the use of pre-engineered porous layers while dramatically improving production speed and productivity
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
LCW enables the production of porous 3D metal structures with controlled porosity and morphology, suitable for various electrochemical and non-electrochemical applications, including batteries, fuel cells, and miniaturized heat exchangers, while reducing production costs and overcoming scalability issues.
Implementation Method 1
joining two or more metal or metal composite substrates immersed into liquid electrolyte solution by means of metal or metal composite deposited from the electrolyte solution during localized electrochemical reaction
Implementation Method 2
applying an electric current flowing from working electrode (WE), through the porous metal substrate layers between perforated non-conductive frames to a counter electrode (CE)
Data Source
AI summary
The application discloses a method of liquid cold welding (LCW) including: (a) engaging two or more porous conductive substrate layers between perforated non-conductive frames so that the substrate layers contact one another; (b) immersing the substrate layers in an electrolyte solution; and (c) applying electric current and/or voltage and/or electric power to the electrolyte solution. Apparatus suitable for performance of some embodiments of the method are also disclosed.