Discretely Supported Wet Side Plates for Fuel Cell Water Transfer
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Solution Overview
Problem
Fuel cell systems, particularly PEM fuel cells, face challenges in maintaining balanced water levels, leading to issues like flooding or dehydration, and existing water vapor transfer (WVT) separator plate assemblies are costly, time-consuming to manufacture, and contribute to increased size and weight.
Innovation Solution
A thinner, lighter WVT separator plate assembly is created by using a pair of wet side separators with WVT membranes facing each other, eliminating the need for a traditional dry side plate and using spacers and discrete supports to define the dry side flow channel, reducing the overall thickness and part count, and employing a roll-based manufacturing process for continuous formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a traditional dry side plate with integral flow channels is used in the WVT separator assembly, then the structural support and flow channel definition are provided, but the overall dimensions, weight, and manufacturing complexity increase
Solution Approach 1:
The patent removes the traditional dry side plate component entirely from the WVT separator assembly. Instead, the flow channels are defined by the spacing between adjacent separator plates and the positioning of GDM layers, eliminating the need for a separate dry side plate structure while maintaining structural support and flow distribution functionality
Solution Approach 2:
The patent combines the functions of the dry side plate (structural support and flow channel definition) with the separator plate and GDM layer assembly. The separator plates and GDM layers work together to provide both structural integrity and flow channel formation, reducing the total number of components and overall assembly thickness
2Reliability
If pressure sensitive adhesive is used to attach GDM and membrane layers to the plastic plate, then the layers are securely bonded, but the manufacturing process becomes time-consuming and costly
Solution Approach 1:
The patent replaces the chemical bonding method (pressure sensitive adhesive) with a mechanical assembly approach using discrete support structures and precise layer positioning. The GDM and membrane layers are held in place by the physical spacing between separator plates and the structural framework, eliminating the need for adhesive application and curing processes
Solution Approach 2:
The patent divides the separator assembly into discrete, modular components (separator plates, GDM layers, membranes, support structures) that can be independently manufactured and assembled. This segmentation allows for simplified assembly processes without requiring adhesive bonding between all layers, improving manufacturing efficiency
3Ease of manufacture
If a plastic plate with integral flow channels is used, then the flow channels are pre-formed and structurally integrated, but the overall size and weight of the separator assembly increase
Solution Approach 1:
The patent eliminates the plastic plate component entirely, extracting the flow channel formation function from a solid plate structure. Instead, flow channels are created as void spaces between discrete separator plates and GDM layers, significantly reducing the amount of material required and overall assembly weight
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 achieves a significant reduction in dry side flow channel height, improves water transfer rates, reduces material usage and costs, and minimizes part count, resulting in a more efficient and cost-effective WVT unit with enhanced performance.
Implementation Method 1
The membrane allows water vapor to pass through it from the higher humidity fluid to the lower humidity fluid while inhibiting the undesirable direct passage of inlet gases
Data Source
AI summary
A water vapor transfer separator plate assembly and a method of making the same. In such an assembly made up of a stack of alternating wet side plates and dry side plates with a membrane disposed between them, a humid fluid such as that found in a fuel cell cathode exhaust flows against one side of each membrane such that at least some of its moisture content travels across the membrane to a lower humidity fluid on the opposite side of the membrane. The lower humidity fluid, such as that found in a fuel cell cathode entrance, experiences an increase in its humidity by the operation of the moisture flow across the membrane. At least a portion of the assembly may be made thinner by removing diffusion media and reinforcing structure of the dry side plates such that the overall assembly is simplified.