PVD Coating for SOFC Electrolytes and Interconnects
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Solution Overview
Problem
The air plasma thermal spray process for depositing oxidation protection barrier layers in fuel cell components is costly due to low deposition efficiency and high material wastage, and traditional screen printing methods for SOFC electrodes require thick electrolytes, leading to bulk strength issues and increased costs.
Innovation Solution
The use of physical vapor deposition (PVD) methods, such as sputtering, to deposit layers on interconnects and SOFC electrolytes, allowing for thinner electrolytes and electrodes, reducing costs and improving performance by increasing deposition efficiency and reducing bulk resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If air plasma thermal spray process is used to deposit oxidation protection barrier layers, then deposition can be achieved, but deposition efficiency is low and material wastage is high
Solution Approach 1:
The patent replaces the air plasma thermal spray process (a mechanical/thermal deposition method) with an electrodeposition process. In electrodeposition, metal ions are deposited onto the interconnect surface through electrochemical reduction in an aqueous solution, eliminating the high material wastage and low efficiency associated with thermal spray methods. The electrochemical process allows for near-100% material utilization efficiency.
Solution Approach 2:
The patent changes the deposition parameters by using electrochemical potential control instead of thermal energy. By controlling the electrodeposition potential and current density, the process achieves precise control over deposition rate and material utilization, transforming the deposition mechanism from a wasteful thermal spray process to an efficient electrochemical process.
2Ease of manufacture
If screen printing method is used for SOFC electrodes, then electrodes can be deposited, but thick electrolytes are required leading to bulk strength issues and increased costs
Solution Approach 1:
The patent replaces the screen printing method (a mechanical contact deposition process) with electrodeposition. Screen printing requires thick electrolytes to provide sufficient bulk strength during the mechanical handling and drying processes. Electrodeposition eliminates these mechanical stress issues by depositing electrodes directly from an aqueous solution through electrochemical reactions, allowing for thinner electrolyte membranes without compromising structural integrity.
Solution Approach 2:
The electrodeposition process occurs in an aqueous solution environment that provides uniform deposition without the mechanical stresses of screen printing. This inert chemical environment allows for precise control of electrode formation on thin electrolytes, eliminating the need for thick substrates required by mechanical contact methods.
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
PVD methods like sputtering enhance deposition efficiency, enable the use of thinner electrolytes and electrodes, lower manufacturing costs, and improve cell performance by reducing bulk resistance and degradation, while also providing a cleaner and more defect-free process.
Implementation Method 1
depositing at least one electrode on the electrolyte by PVD, such as sputtering
Implementation Method 2
depositing at least one electrode on the electrolyte by PVD, such as sputtering
Data Source
AI summary
A method of making a solid oxide fuel cell (SOFC) includes providing a solid oxide electrolyte and depositing at least one electrode on the electrolyte by PVD, such as sputtering. A method of making an interconnect for a fuel cell stack includes providing an electrically conductive interconnect, and depositing a layer on the interconnect by PVD, such as depositing a LSM barrier layer by sputtering. The SOFC and the interconnect may be located in the same fuel cell stack.