Hydrophilic Gas Diffusion Layer for Fuel Cell Wet Seal
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Solution Overview
Problem
Evaporatively cooled fuel cells face challenges in water distribution and containment, leading to inefficient operation due to increased water transport requirements and potential hydrogen migration, especially when using low pressure water flow and porous plates.
Innovation Solution
A fuel cell design featuring a porous anode plate with interconnected fuel and coolant passages, a hydrophilic gas diffusion layer to distribute water and maintain a wet seal within the porous network, limiting fuel transport and preventing hydrogen migration by forming a gas barrier.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If evaporative cooling is used with low pressure water flow, then cooling efficiency is improved, but water transport requirements increase and hydrogen migration risk increases
Solution Approach 1:
The patent employs a porous anode plate with controlled pore structure to enable efficient water transport through capillary forces. The porous material allows water to move from coolant channels to the reaction zone without requiring high pressure, thereby maintaining evaporative cooling efficiency while reducing the quantity of water needed for transport.
Solution Approach 2:
The patent applies hydrophilic coating to specific regions of the anode plate to create localized water transport pathways. This local quality enhancement ensures water is delivered precisely where needed for evaporative cooling and reaction, optimizing cooling efficiency while minimizing overall water consumption.
2Quantity of substance
If porous plates are used for water distribution, then water transport is improved, but hydrogen containment deteriorates due to potential migration
Solution Approach 1:
The patent creates distinct regions within the porous anode plate with different properties: hydrophilic regions for water transport and hydrophobic regions for hydrogen containment. This local differentiation allows water to move freely through porous structures while hydrogen is blocked by the hydrophobic barriers, preventing migration.
Solution Approach 2:
The patent introduces a hydrophilic/hydrophobic interface as an intermediary mechanism between water transport and hydrogen containment functions. This interface acts as a selective barrier that allows water passage while blocking hydrogen, resolving the contradiction between water distribution and hydrogen containment.
3Object-generated harmful factors
If a wet seal is established in the porous network, then hydrogen containment is improved, but water transport capability may be reduced
Solution Approach 1:
The patent segments the porous anode plate into multiple functional zones: water supply channels, reaction zones with wet seals, and water transport pathways. This segmentation allows the wet seal to form in specific regions for hydrogen containment while leaving other pathways open for water transport, preventing the contradiction between containment and transport.
Solution Approach 2:
The patent employs a dynamic wet seal mechanism where the seal strength adjusts based on local water content and pressure conditions. In regions where hydrogen containment is critical, the wet seal forms strongly; in regions where water transport is needed, the seal remains weaker, allowing water passage while maintaining hydrogen barrier function elsewhere.
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
The design effectively maintains a wet seal, preventing hydrogen from mixing with oxidant and ensuring efficient fuel cell operation by distributing water to circumvent obstructions and maintain hydration within the porous network, even under low pressure and low water flow conditions.
Implementation Method 1
A hydrophilic gas diffusion layer between the membrane electrode arrangement and the porous anode plate distributes water from the coolant flow passages to help maintain a wet seal within the network of pores
Implementation Method 2
maintain a wet seal within the network of pores that limits fuel transport through the network of pores from the fuel flow passages to the coolant flow passages
Implementation Method 3
a membrane electrode arrangement adjacent the fuel flow passages generates electricity in a fuel cell reaction
Implementation Method 4
transport the water through the anode plate to the anode to absorb heat and evaporatively cool the fuel cell during operation
Data Source
AI summary
An example fuel cell stack (10, 40) includes a cathode plate (60) having oxidant flow passages (62) and coolant flow passages (64), and a porous anode plate (42) adjacent the coolant flow passages (64). The porous anode plate (42) includes fuel flow passages (46) and a network of pores (44) that fluidly connect the fuel flow passages (46) and the coolant flow passages (64). A membrane electrode arrangement (50) adjacent the fuel flow passages (46) generates electricity in a fuel cell reaction. A hydrophilic gas diffusion layer (48) between the membrane electrode arrangement (50) and the porous anode plate (42) distributes water from the coolant flow passages (64) to maintain or establish a wet seal (70) within the network of pores (44) that limits fuel transport through the network of pores (44) from the fuel flow passages (46) to the coolant flow passages (64).