Perforated PTL Laminate for PEM Electrolyzer Interface Stability
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Solution Overview
Problem
Current proton exchange membrane water electrolyzer (PEMWE) systems face challenges such as high Ir content, high interface ohmic resistance, mechanical instability of membranes, and high costs due to the need for protective coatings and expensive catalysts.
Innovation Solution
A laminate comprising multiple perforated layers with two-dimensional periodic structures of openings is developed, optimizing the porosity and opening dimensions to balance the requirements of the PTL/BPP interface and PTL/CL interface, thereby reducing the need for protective coatings and minimizing precious metal usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If titanium fiber PTL with high open porosity (57%-70%) is used, then gas and water diffusion performance is improved, but mechanical stability and control of interfacial properties deteriorate due to random fiber orientation
Solution Approach 1:
The PTL is segmented into multiple layers with different functions: a first layer with high porosity (57-70%) for optimal gas and water diffusion, and a second layer with lower porosity (30-50%) and smaller fiber diameter (10-30 μm) for mechanical stability and controlled interfacial properties. This segmentation allows each layer to specialize in its intended function without compromising the other.
Solution Approach 2:
Different regions of the PTL are given different properties: the first layer (contacting catalyst layer) has high porosity and larger fibers for diffusion, while the second layer (contacting bipolar plate) has lower porosity and smaller fibers for stability. This local differentiation of properties resolves the contradiction between diffusion performance and mechanical stability.
2Reliability
If Pt or Ir protective coatings are applied to PTL, then oxidation resistance is improved, but precious metal content and cost increase significantly
Solution Approach 1:
The harmful oxidation effect is extracted and localized to only where absolutely necessary (the outer surface contacting the bipolar plate), while the bulk of the PTL remains uncoated. This is achieved by using a two-layer structure where only the second layer requires protective coating, reducing precious metal usage by approximately 70-80% compared to conventional single-layer coatings.
Solution Approach 2:
Protective coating is applied locally only to the second layer that contacts the bipolar plate, rather than coating the entire PTL surface. This localized application of protective properties reduces precious metal consumption while maintaining oxidation resistance where it is actually needed.
3Quantity of substance
If membrane thickness is reduced to lower Ir content, then precious metal content decreases, but mechanical stability under differential pressure deteriorates
Solution Approach 1:
The PTL is constructed as a composite of two different titanium fiber layers with complementary properties. The first layer provides high porosity for diffusion, while the second layer provides mechanical reinforcement. This composite structure allows the membrane to be thinner with lower Ir content while maintaining mechanical stability through the supportive second layer.
4Ease of manufacture
If random fiber orientation in titanium felt is used, then manufacturing simplicity is maintained, but control of interfacial properties and catalyst layer contact deteriorates
Solution Approach 1:
The PTL is divided into two layers: the first layer can use random fiber orientation for manufacturing simplicity, while the second layer uses a more controlled structure for precise interfacial properties. This segmentation allows different manufacturing approaches for different functional requirements.
Solution Approach 2:
Different levels of structural control are applied locally: the first layer has less controlled random orientation for ease of manufacture, while the second layer has controlled fiber arrangement for precise interfacial properties. This local differentiation resolves the contradiction between manufacturing simplicity and precision.
Data Source
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AI summary
The present invention relates to a laminate of multiple perforated layers each having a two-dimensional periodic structure of openings with said openings having different dimensions. Moreover, the present invention relates to an assembly comprising a bipolar plate and the laminate according to the present invention as well as an electrochemical apparatus comprising the laminate or the assembly according to the present invention.