Fuel Cell Insulating Member Frame for Reactant Gas Distribution
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Solution Overview
Problem
Fuel cells experience reduced power generation efficiency when the flow rate of reactant gas around the membrane electrode gas diffusion layer assembly is high, as it fails to effectively reach the membrane electrode assembly for the power generation reaction.
Innovation Solution
Incorporating an insulating member with a frame shape and elastic portions of varying compressibility between separators, which reduces the cross-sectional area of flow paths, ensuring that reactant gas flows efficiently to the membrane electrode assembly by compressing certain regions and maintaining non-compressed regions in the flow paths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the flow rate of reactant gas passing around the membrane electrode gas diffusion layer assembly is increased, then the cooling effect and gas supply to the separator are improved, but the power generation efficiency is reduced due to insufficient gas reaching the membrane electrode assembly
Solution Approach 1:
The insulating member is designed with differentiated regions: a compressed region with smaller cross-sectional area and a non-compressed region with larger cross-sectional area. This local quality variation directs the reactant gas flow preferentially through the non-compressed region, ensuring sufficient gas reaches the membrane electrode assembly for power generation while maintaining overall high flow rates for cooling and separator supply.
Solution Approach 2:
The insulating member is segmented into functionally distinct regions: the compressed region that reduces flow resistance and the non-compressed region that maintains flow path area. This segmentation allows independent optimization of gas flow distribution, ensuring that power generation efficiency is improved by directing adequate reactant gas to the membrane electrode assembly while still providing sufficient cooling and separator gas supply.
2Speed
If the cross-sectional area of the flow path is reduced, then the gas flow velocity increases and cooling effect improves, but the total gas flow rate decreases reducing power generation efficiency
Solution Approach 1:
The insulating member utilizes the thickness dimension (Z-direction) to compensate for the reduced cross-sectional area in the flow path. By increasing the thickness of the non-compressed region, the flow path volume is maintained or increased, allowing both high gas flow velocity (improved cooling) and high total gas flow rate (improved power generation efficiency) to coexist.
Solution Approach 2:
Different regions of the insulating member have different thicknesses: the compressed region has smaller thickness while the non-compressed region has larger thickness. This local quality variation in the thickness dimension allows the non-compressed region to maintain sufficient flow path volume for high total gas flow rate, while the overall compact design maintains high gas flow velocity for effective cooling.
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 configuration enhances the power generation efficiency by ensuring that reactant gas reaches the membrane electrode assembly effectively, improving fuel consumption and reducing the power consumption of pumps and compressors used in fuel cell systems.
Implementation Method 1
an insulating member (50) including: a base member (51) formed into a frame shape; and a first elastic portion (52) provided beforehand on a first surface (51a) of the base member (51) facing the first separator (20), an elastic modulus of the first elastic portion (52) being smaller than an elastic modulus of the base member (51)
Data Source
AI summary
A fuel cell includes: a membrane electrode gas diffusion layer assembly in which a membrane electrode assembly is sandwiched by a pair of gas diffusion layers; an insulating member formed into a frame shape, and being in contact with an outer peripheral portion of the membrane electrode gas diffusion layer assembly; and first and second separators sandwiching the membrane electrode gas diffusion layer assembly and the insulating member.