Fuel Cell Stack Frame Coating for Metal Volatilization Prevention
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Solution Overview
Problem
In fuel cell stack structures, the volatilization and diffusion of metal materials from frames lead to degradation of electroconductive properties and sealability issues, causing electrical shunts and reduced performance due to material property differences and impurity reactions.
Innovation Solution
A stack structure with a combined functional layer of insulating ceramic material coated on the entire surface of the frame, including metal-mixed materials like chromium, to prevent metal material volatilization and diffusion, and improve adhesive strength between the frame and sealing units, while maintaining electrical insulation and preventing impurity-induced electrical shunts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a frame including metal material is used to reinforce the strength of the interconnector, then the strength and structural stability are improved, but the metal material volatilizes and diffuses at high temperature, degrading the electroconductive property of the cathode layer
Solution Approach 1:
A barrier layer is introduced as an intermediary between the metal frame and the cathode layer. This barrier layer prevents direct contact and interaction between the metal material and the cathode layer, thereby blocking the volatilization and diffusion of metal materials that would otherwise degrade the electroconductive property of the cathode layer while allowing the metal frame to maintain its structural strength function
Solution Approach 2:
The interconnector is designed as a composite structure combining metal frame material with ceramic coating material. The metal frame provides mechanical strength while the ceramic coating layer prevents high-temperature volatilization and diffusion of metal materials, creating a composite material system that simultaneously achieves both strength and electroconductive property preservation
2Reliability
If the sealing unit is disposed between the frame and the interconnector, then the sealability is improved, but the frame and sealing unit separate due to different material properties under dramatic temperature changes, leading to breakdown of sealability
Solution Approach 1:
The sealing structure is designed as a composite system where the barrier layer on the frame and the sealing unit are both made of ceramic materials with matched thermal expansion coefficients. This material compatibility ensures that the sealing unit remains adhered to the frame even under dramatic temperature changes, preventing separation and maintaining sealability
Solution Approach 2:
The barrier layer is designed with specific material parameters including thermal expansion coefficient and melting point that match or are compatible with the sealing unit material. By carefully selecting and controlling these material parameters, the adhesive strength between the frame coating and sealing unit is maintained across the operating temperature range, preventing separation
3Volume of stationary object
If the single cells and interconnectors are formed to very small thicknesses to reduce the volume of the stack structure, then the volume is reduced, but the strength between interconnectors is insufficient, causing bending or sagging during operation
Solution Approach 1:
The interconnector is constructed as a composite structure with a metal frame core providing high mechanical strength and a ceramic barrier layer providing environmental stability. This composite design allows the interconnector to maintain sufficient strength to prevent bending or sagging while keeping the overall thickness and volume of the stack structure minimized
4Reliability
If the frame is coated with insulating ceramic material to prevent metal volatilization, then the electroconductive property is preserved, but the adhesive strength between the coating and frame may be reduced due to different material properties
Solution Approach 1:
The barrier layer is made of insulating ceramic material that is chemically and physically compatible with both the metal frame substrate and the cathode layer. This composite material selection ensures that the coating adheres strongly to the frame while simultaneously preventing metal volatilization and preserving the electroconductive property of the cathode layer
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 solution effectively stabilizes the electroconductive and catalytic properties of the cathode layer, maintains sealability, and prevents electrical shunts, ensuring long-term stable electricity generation by preventing composite oxide formation and impurity reactions.
Implementation Method 1
coating a combined functional layer for preventing volatilization or diffusion of a metal material on an entire surface of a frame
Implementation Method 2
coating a combined functional layer for preventing volatilization or diffusion of a metal material on an entire surface of a frame
Implementation Method 3
improve an adhesive strength between the frame and a sealing unit
Implementation Method 4
maintaining electrical insulation and preventing impurity-induced electrical shunts
Data Source
AI summary
Provided is a stack structure for fuel cells. The stack structure includes a plurality of fuel cells stacked to generate electricity. The stack structure further includes an interconnector and a frame. The interconnector is divided into a central region supporting and electrically connected with the fuel cells and an edge region outwardly extending from an end of the fuel cell. The frame is disposed to support a side of the fuel cell in the edge region of the interconnector, and has a combined functional layer coated on an entire surface of the frame.