Fuel Cell Humidifier Plate Stack for Membrane Support and Tight Spacing
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Solution Overview
Problem
Existing fuel cell humidifiers face challenges in achieving high surface area exposure of membranes to exchange gases at controlled fluid flow rates while maintaining thin plates for tight cell spacing, and ensuring effective assembly without damaging fragile membrane/diffusion layer media.
Innovation Solution
A humidifier design featuring a stack of plates with alternating wet and dry gas flow passages, supported by water-permeable membranes and gas diffusion layers, with support structures like ribs and webs to maintain membrane integrity and facilitate efficient water vapor transfer between gas streams.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If plates are made thin to achieve tight cell spacing, then device size is reduced, but structural strength and ability to maintain consistent spacing deteriorates
Solution Approach 1:
The plate combines multiple materials with complementary properties: a thin polymer substrate provides flexibility and chemical compatibility, while integrated ribs made of more rigid material provide structural support. This composite structure allows the plate to maintain both thinness for compact size and sufficient strength for maintaining cell spacing.
2Productivity
If membrane surface area is increased to improve water vapor transfer efficiency, then humidification performance is improved, but device complexity and manufacturing difficulty increases
Solution Approach 1:
The membrane is arranged in a serpentine pattern that extends in multiple directions across the plate surface, effectively increasing the surface area within the same footprint. This dimensional arrangement allows high surface area exposure without proportionally increasing device volume or manufacturing complexity.
Solution Approach 2:
The continuous membrane is divided into multiple segments by the rib structures, creating a modular pattern that is easier to manufacture and assemble. The segmentation allows for standardized production of plate-membrane-plate assemblies while still achieving high total surface area through the repeated pattern.
3Reliability
If compressive forces are increased to secure membrane assembly, then assembly reliability is improved, but risk of damaging fragile membrane/diffusion layer media increases
Solution Approach 1:
Compressive forces are applied locally at the rib structures rather than uniformly across the entire membrane surface. The ribs act as force distribution elements that concentrate the clamping load at specific points, securing the membrane assembly reliably while leaving the membrane areas between ribs stress-free and undamaged.
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 design enhances the efficiency and durability of fuel cell humidifiers by maximizing membrane exposure, maintaining consistent cell spacing, and supporting the fragile membrane/diffusion layer media, thereby improving the humidification process.
Implementation Method 1
water vapour is transferred from the wet gas stream, across the water-permeable membrane and through the gas diffusion layers, into the dry gas stream
Implementation Method 2
water vapour is transferred from the wet gas stream, across the water-permeable membrane and through the gas diffusion layers, into the dry gas stream
Data Source
AI summary
A humidifier for a fuel cell system comprises a stack of thin plates having planar sealing surfaces at their edges. A water permeable membrane is provided between each pair of plates. Each plate defines a gas flow passage along its top and bottom surfaces, with an inlet and outlet defined along edges of the plate, and a flow field extending between the inlet and outlet openings. Inlet and outlet passages connect the inlet and outlet openings to the flow field, and the planar sealing surfaces on both sides of the plate include bridging portions which extend across the inlet and outlet passages. Support structures are provided throughout the flow field and the inlet and outlet passages to support the membrane and diffusion medium layer(s). The support structures may optionally be connected together by webs having holes for flow distribution between the top and bottom of each plate.