Fuel Cell Frame Assembly Preventing Membrane Deterioration
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Solution Overview
Problem
Conventional fuel cell production methods cause polymer electrolyte membrane deterioration due to high-temperature and high-pressure thermoplastic resin contact, leading to reduced power generation performance.
Innovation Solution
The method involves forming an electrode-membrane-frame assembly by arranging previously molded frame components around the membrane-electrode assembly such that the thermoplastic resin is not directly in contact with the membrane, using injection molding to connect these components without direct contact with the membrane, thereby preventing deterioration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the secondary molded body is formed by injection molding with high-temperature thermoplastic resin, then molding precision is ensured, but the polymer electrolyte membrane deteriorates due to heat contact
Solution Approach 1:
The patent introduces an intermediary structure (first molded body and second molded body) between the injection-molded third molded body and the polymer electrolyte membrane. These intermediary molded bodies act as buffers that prevent direct contact between the high-temperature thermoplastic resin and the membrane, thereby resolving the contradiction between achieving molding precision and preventing heat-induced membrane deterioration.
2Manufacturing precision
If high-pressure thermoplastic resin is injected into the die, then sufficient molding precision is achieved, but the polymer electrolyte membrane deteriorates due to pressure contact
Solution Approach 1:
The first molded body and second molded body serve as intermediary structures that absorb and distribute the injection pressure. By positioning these molded bodies between the injection-molded third molded body and the polymer electrolyte membrane, the patent prevents direct transmission of high pressure to the membrane while still achieving sufficient molding precision for the frame structure.
3Ease of manufacture
If the thermoplastic resin directly contacts the catalyst layer, then the frame structure is formed, but the polymer electrolyte membrane deteriorates as the resin reaches the membrane through the catalyst layer
Solution Approach 1:
The frame structure is segmented into multiple independent molded bodies (first molded body, second molded body, and third molded body) rather than forming a single integrated frame. This segmentation allows each component to be manufactured separately and assembled in a controlled manner, preventing the thermoplastic resin from directly contacting and penetrating through the catalyst layer to reach the polymer electrolyte membrane.
4Productivity
If injection molding is used to form the frame, then production efficiency is improved, but the polymer electrolyte membrane deteriorates due to high-temperature resin contact
Solution Approach 1:
The first molded body and second molded body are prepared in advance through injection molding before the final assembly step. This preliminary action allows the majority of the frame structure to be manufactured efficiently through injection molding, while the subsequent assembly of the third molded body completes the frame without requiring the membrane-containing MEA to be present during the high-temperature molding process, thus maintaining both productivity and membrane integrity.
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 approach enhances adhesion between the frame and membrane-electrode assembly, prevents membrane deterioration, and maintains power generation performance.
Implementation Method 1
it is necessary to melt the thermoplastic resin, so that a temperature of the thermoplastic resin when poured into the die is as high as 200° C. or more
Implementation Method 2
When the high-temperature thermoplastic resin directly comes in contact with the polymer electrolyte membrane 111 in forming the secondary molded body 102B by injection molding, the polymer electrolyte membrane 111 could deteriorate (a membrane thickness is reduced, or a strength is lowered) due to the heat of the thermoplastic resin
Implementation Method 3
an injection pressure of the thermoplastic resin into the die needs to be ten times as high as a fastening pressure of the cell to ensure sufficient molding precision
Implementation Method 4
When the high-pressure thermoplastic resin is directly in contact with the polymer electrolyte membrane 111 in forming the secondary molded body 102B by injection molding, the polymer electrolyte membrane 111 could deteriorate due to the pressure of the thermoplastic resin
Data Source
AI summary
A method for producing an electrode-membrane-frame assembly according to the present invention includes arranging a previously molded first molded body on a circumferential region of first catalyst layer close to first gas diffusion layer, arranging a previously molded second molded body on a circumferential region of second catalyst layer close to second gas diffusion layer, and forming a third molded body by injection molding so as to integrally connect the first molded body and the second molded body and not to be directly in contact with an inner side region of second main surface of a polymer electrolyte membrane positioned on an inner side of an outer edge part of the second molded body when viewed from a thickness direction of the polymer electrolyte membrane, whereby a frame having the first, second, and the third molded body is formed. Thus, the polymer electrolyte membrane can be prevented from deteriorating.