Fuel Cell MEA Frame Elastic Sealing Injection Molding
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Solution Overview
Problem
Conventional solid polymer electrolyte fuel cells face issues with cross-leak phenomena due to clearance between the polymer electrolyte membrane and the frame, leading to inefficient gas utilization and performance limitations, particularly with binding methods using thermal pressure bonding or mechanical cramps, which can cause membrane deterioration and dimensional control challenges.
Innovation Solution
The introduction of an elastic member structure comprising inner and outer elastic members connected by connecting elastic members, which are formed through injection molding to hermetically seal the space between the electrode-membrane-frame assembly and the separators, reducing clearance and enhancing gas utilization efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If thermal pressure bonding or adhesive methods are used to bind the polymer electrolyte membrane, then the membrane can be secured to the frame, but the performance of the polymer electrolyte membrane deteriorates due to heat and volatile components
Solution Approach 1:
The patent replaces thermal bonding and adhesive methods with a mechanical compression system. The frame compresses the polymer electrolyte membrane against the electroconductive separator through mechanical force, eliminating the need for heat or chemicals that would damage the membrane. This is achieved through the frame's structure that applies uniform compression pressure across the membrane surface.
2Strength
If a mechanical cramp is used to bind the polymer electrolyte membrane, then the membrane can be secured, but cross-leak from fine clearance between the membrane and frame easily occurs
Solution Approach 1:
The patent employs the electroconductive separator as a flexible sealing element that deforms under compression to fill clearance gaps. The separator's flexibility allows it to conform to the frame's inner surface and maintain hermetic sealing, preventing cross-leak while accommodating dimensional variations in the assembled components.
3Reliability
If a second gasket is arranged in the clearance to prevent cross-leak, then the sealing performance improves, but the production cost increases and dimensional control becomes difficult
Solution Approach 1:
The patent makes the electroconductive separator serve multiple functions: it conducts electricity for the fuel cell reaction, provides mechanical support for the membrane, and acts as a sealing element to prevent cross-leak. This multi-functionality eliminates the need for separate gasket components, reducing structural complexity and production cost while maintaining reliable sealing.
4Stability of the object's composition
If the polymer electrolyte membrane is tightly bound to the frame, then assembly stability improves, but the fragile gas diffusion electrodes are damaged
Solution Approach 1:
The patent controls the compression pressure parameter to achieve optimal sealing without damaging the electrodes. By adjusting the frame's compression force to an appropriate level, the system maintains hermetic sealing to prevent cross-leak while staying below the threshold that would damage the fragile gas diffusion electrodes. This parameter optimization balances sealing performance with electrode protection.
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
This solution effectively suppresses the cross-leak phenomenon, improving the utilization ratio of reductant and oxidizer gases and enhancing the overall performance of the polymer electrolyte fuel cell by ensuring a hermetic seal without damaging the fragile gas diffusion electrodes.
Implementation Method 1
each of the elastic members is elastically deformed in a direction of a thickness of the electrode-membrane-frame assembly to hermetically seal the space between the electrode-membrane-frame assembly and the separator
Implementation Method 2
arranging an electrode-membrane-frame assembly in a mold for injection molding to form a first flow passage arranged on the electrolyte membrane so as to extend along the outer periphery of the electrode
Implementation Method 3
curing the filled elastic resin, thereby integrating elastic members which are elastically deformed in a thickness direction of the electrode-membrane-frame assembly
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
A MEA-frame assembly is arranged in a mold for injection molding to form a first flow passage arranged so as to extend along the outer periphery of an electrode between the outer periphery of the electrode and the inner periphery of a frame, a second flow passage arranged so as to extend along an inner elastic member between the inner periphery and outer periphery of the frame and a plurality of connecting flow passages which communicate the first flow passage with the second flow passage. An elastic resin is injected into the first flow passage to fill the first flow passage with the elastic resin and to fill the second flow passage with the elastic resin through each of the communicating flow passages, thereby an elastic member which hermetically seals the space between the MEA-frame assembly and the separator is integrally formed.