Fuel Cell Separator with Thin Clearance for Membrane Protection

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Solution Overview

Problem

Existing fuel cell designs face challenges in achieving optimal power generation performance and preventing damage to the solid polymer electrolyte membrane due to uneven gas diffusion layer sizes and stress concentrations during assembly and operation.

Innovation Solution

A fuel cell design featuring a membrane electrode assembly with a first gas diffusion layer larger than a second gas diffusion layer, where the anode-side separator includes a thin clearance part to reduce stress on the smaller gas diffusion layer, preventing membrane damage and ensuring reliable power generation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If the gas diffusion layers are designed with different planar sizes (step MEA configuration), then the power generation performance can be optimized through asymmetric electrode design, but stress concentration occurs at the boundaries during assembly and operation which may damage the solid polymer electrolyte membrane

Engineering Contradiction:

Improvepower generation performanceVSAvoidmembrane strength

Core Design Contradiction:

PowerVSStrength

Solution Approach 1:

The patent applies local quality by creating a stepped configuration where different regions of the membrane electrode assembly have different gas diffusion layer sizes. The first gas diffusion layer has a larger planar size than the second gas diffusion layer, allowing optimization of reactant distribution and current density in different zones. This asymmetric design improves power generation performance while the thinner separator portion is strategically positioned to protect the membrane in the region where the smaller gas diffusion layer contacts the separator.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent segments the separator into regions of different thicknesses. The separator has a first portion with a greater thickness and a second portion with a lesser thickness, corresponding to different regions of the membrane electrode assembly. This segmentation allows the separator to provide enhanced mechanical support where needed while maintaining close contact in other regions, thereby preventing stress concentration and membrane damage at the boundaries of the asymmetric gas diffusion layers.

Inventive Principle:

Principle #1Segmentation

2Ease of manufacture

If the separator is made with uniform thickness, then manufacturing is simplified, but stress concentration occurs at the boundaries of the smaller gas diffusion layer during assembly and operation

Engineering Contradiction:

Improveseparator manufacturing simplicityVSAvoidstress concentration on membrane

Core Design Contradiction:

Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The separator is designed with local quality variations, having different thicknesses in different regions. The first portion has a greater thickness while the second portion has a lesser thickness, corresponding to the regions beneath the larger and smaller gas diffusion layers respectively. This non-uniform thickness distribution is strategically implemented to provide mechanical support where stress concentration occurs, while maintaining manufacturing feasibility through conventional forming processes.

Inventive Principle:

Principle #3Local quality

3Ease of operation

If the smaller gas diffusion layer is allowed to contact the separator directly, then assembly is simplified, but the solid polymer electrolyte membrane may be damaged due to stress concentration at the boundaries

Engineering Contradiction:

Improveassembly simplicityVSAvoidmembrane durability

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The separator is segmented into regions of different thicknesses to address the boundary stress issue. The second portion with lesser thickness is positioned to allow the smaller gas diffusion layer to contact the separator, while the first portion with greater thickness provides structural support in the region adjacent to the boundary. This segmentation enables direct contact assembly simplicity while preventing membrane damage through strategic thickness variation.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The thicker first portion of the separator acts as a cushioning structure positioned beforehand to prevent stress concentration at the boundary regions. By providing enhanced mechanical support in advance in the region adjacent to the smaller gas diffusion layer boundary, the design prevents potential membrane damage during assembly and operation while allowing direct contact in the central region.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

Data Source

PatentUS9780400B2Fuel cell having an empty space gap between the separator and electrode

Publication Date: 2017.10.03 HONDA MOTOR CO LTD

AI summary

A fuel cell includes a membrane electrode assembly interposed between a cathode-side separator and an anode-side separator. A first gas diffusion layer included in a cathode is designed to have a planar size larger than a planar size of a second gas diffusion layer included in an anode. The anode-side separator has a thin clearance part in a portion that faces an outer peripheral portion of the second gas diffusion layer.