Fuel Cell Flow Field Plates for Uniform Contact Pressure

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Solution Overview

Problem

Conventional fuel cell flow field plates with constant channel and landing widths lead to non-uniform contact pressure distribution, affecting electrical and thermal contact resistance, reactant access, and mechanical integrity, necessitating a balance between compression force and porosity maintenance.

Innovation Solution

Designing fuel cell assemblies with flow field plates featuring channels and landings of varying widths, employing a non-uniform compressive force system, and using wedge-shaped gas diffusion layers to maintain uniform contact pressure across the active area, compensating for variations in reactant stream pressures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If constant width channels and landings are used in flow field plates, then manufacturing is simplified, but contact pressure distribution becomes non-uniform

Engineering Contradiction:

Improveflow field plate manufacturingVSAvoidcontact pressure distribution

Core Design Contradiction:

Ease of manufactureVSStress or pressure

Solution Approach 1:

The flow field plate is designed with non-uniform landing widths where different regions have different dimensions. Specifically, landings in regions experiencing higher reactant stream pressures are made narrower, while landings in regions with lower pressures are made wider. This local variation in geometry compensates for the non-uniform pressure distribution, achieving substantially uniform contact pressure across the membrane electrode assembly without requiring complex manufacturing processes.

Inventive Principle:

Principle #3Local quality

2Reliability

If higher compressive force is applied to improve contact pressure, then electrical and thermal contact resistance decreases, but porosity of gas diffusion layer is reduced

Engineering Contradiction:

Improveelectrical and thermal contactVSAvoidgas diffusion layer porosity

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

Instead of applying uniformly high compressive force, the invention changes the geometric parameters of the flow field plate landings to achieve uniform contact pressure distribution at moderate compression levels. The non-uniform landing widths are designed to compensate for variations in reactant stream pressure, allowing the system to maintain good electrical and thermal contact without excessive compression that would damage the gas diffusion layer porosity.

Inventive Principle:

Principle #35Parameter changes

3Stress or pressure

If non-uniform compressive force is applied to compensate for pressure variations, then contact pressure uniformity improves, but system complexity increases

Engineering Contradiction:

Improvecontact pressure uniformityVSAvoidcompression system

Core Design Contradiction:

Stress or pressureVSDevice complexity

Solution Approach 1:

Instead of making the compression system non-uniform to compensate for pressure variations, the invention inverts the approach by making the flow field plate geometry non-uniform while maintaining a simple uniform compression system. The non-uniform landing widths in the flow field plate inherently compensate for the non-uniform reactant stream pressures, achieving uniform contact pressure without complex variable force application mechanisms.

Inventive Principle:

Principle #13The other way round (Inversion)

Data Source

PatentUS20230387443A1Fuel Cell Assemblies with Improved Contact Pressure Distribution

Publication Date: 2023.11.30 CEVIZDERE LLC

AI summary

The present technology relates to apparatus and methods for providing contact pressure distribution between fuel cell components in a fuel cell stack. In some embodiments, the technology relates to fuel cell flow field plate designs and to compression systems for fuel cell stacks that can be used, separately or in combination, to provide more uniform contact pressure distribution across the active area of fuel cells in a fuel cell stack.