Wicking Layer Moisture Management in Fuel Cell Plates
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Solution Overview
Problem
PEM fuel cells with solid reactant distribution plates are prone to damage due to dry out, particularly near fuel and air inlets, resulting from incomplete saturation of gas streams.
Innovation Solution
A wicking layer is positioned between the reactant distribution plate and the gas diffusion layer, with a continuous portion covering the condensation zone to absorb and transport moisture towards the air inlet side, while an interrupted portion along the active zone allows unobstructed gas access to the catalyst layers, utilizing hydrophilic materials like carbon or tin oxide treated carbon fiber paper.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a solid reactant distribution plate is used in a PEM fuel cell, then the structural support and reactant distribution are improved, but the risk of dry out damage to components increases due to incomplete saturation of gas streams at inlets
Solution Approach 1:
A wicking layer is introduced as an intermediary component between the solid reactant distribution plate and the gas diffusion layer. This wicking layer absorbs excess liquid water from the condensation zone and transports it via capillary action to the inlet regions, preventing dry out conditions while maintaining the structural integrity of the solid plate design
Solution Approach 2:
The wicking layer is selectively positioned to cover specific regions of the reactant distribution plate - particularly the condensation zone where liquid water accumulates - while leaving other regions exposed. This localized application addresses the specific problem of water management without compromising the overall structural function of the plate
2Reliability
If the wicking layer covers the condensation zone to absorb moisture, then the risk of dry out is reduced, but the gas transport to catalyst layers may be obstructed
Solution Approach 1:
The wicking layer is applied selectively to cover only the condensation zone regions where liquid water removal is needed, while deliberately leaving the active zones with catalyst layers exposed. This localized coverage enables moisture management in specific areas without obstructing gas transport pathways to the catalyst layers
Solution Approach 2:
The reactant distribution plate is functionally segmented into a condensation zone (covered by wicking layer) and an active zone (exposed for gas transport). This segmentation allows different regions to perform different functions - water absorption in the condensation zone and gas distribution in the active zone - resolving the contradiction between moisture management and reactant transport
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
Effectively manages moisture distribution within the fuel cell, reducing the risk of dry out and maintaining efficient reactant transport to the catalyst layers without the need for additional humidification devices, thereby enhancing fuel cell operation and component durability.
Implementation Method 1
a wicking layer that is useful for absorbing liquid water while a fuel cell operates, for example, and transporting or wicking the liquid water toward dry parts of a fuel cell
Implementation Method 2
utilizing hydrophilic materials like carbon or tin oxide treated carbon fiber paper
Data Source
AI summary
An exemplary device for managing moisture content within a fuel cell includes a reactant distribution plate having a plurality of members that establish reactant flow channels that are open on at least one side of the plate. A wicking layer is against the one side of the plate. The wicking layer includes a first portion that is uninterrupted and covers over at least some of the channels. A second portion of the wicking layer extends along ends of at least some of the members such that sections of the channels coextensive with the second portion are open toward the one side.