Diffusion-Bonded Porous Transport Layers for Low-Resistance PEMWE Cells
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Solution Overview
Problem
Current electrochemical cells with porous transport layers (PTLs) suffer from limited electrical conductivity and mass transport efficiency due to poorly interconnected layers and material anisotropy, leading to suboptimal performance in proton exchange membrane water electrolysis (PEMWE) systems.
Innovation Solution
The development of improved PTLs through a combination of titanium fiber felt and titanium powder layers, with subsequent sintering and laser treatment to create a uniform interface with flow field plates, enhancing conductivity and porosity, and potentially incorporating embedded catalysts and advanced manufacturing techniques like tape casting and diffusion bonding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional porous transport layers are used in electrochemical cells, then the structure is simple and manufacturing is easy, but electrical conductivity and mass transport efficiency are limited due to poorly interconnected layers and material anisotropy
Solution Approach 1:
The patent combines multiple titanium layers (titanium felt, titanium powder, and titanium mesh) into a single integrated porous transport layer structure. This merging of layers improves electrical conductivity and mass transport efficiency by creating well-interconnected pathways while maintaining structural integrity through diffusion bonding and sintering processes.
Solution Approach 2:
The patent employs a composite structure consisting of different titanium-based materials (felt, powder, mesh) with complementary properties. The titanium felt provides mechanical strength and porosity, titanium powder enhances electrical conductivity when sintered, and titanium mesh offers structural support. This composite approach resolves the contradiction by achieving superior electrical and mass transport properties without excessive complexity.
2Reliability
If uniform interface between PTL and flow field plate is achieved through diffusion bonding, then contact resistance and corrosion are reduced, but manufacturing process complexity and cost increase
Solution Approach 1:
The patent applies preliminary surface treatments to the PTL and flow field plate surfaces before diffusion bonding, including laser texturing and chemical etching. These preliminary actions create micro-roughness and increase surface area, promoting better diffusion bonding and reducing contact resistance. By preparing surfaces in advance, the actual bonding process becomes more reliable and less complex.
Solution Approach 2:
The patent utilizes parameter changes in the diffusion bonding process, specifically controlling temperature (900-1100°C), pressure (5-50 MPa), and time (5-30 minutes) to achieve optimal bonding. By precisely adjusting these parameters, the process creates a uniform interface with minimal contact resistance and enhanced corrosion resistance, making the complex process controllable and repeatable.
3Quantity of substance
If larger pores are used in the PTL, then permeability is improved, but electrical and thermal conductivity deteriorate
Solution Approach 1:
The patent applies local quality by creating different pore size distributions in different regions of the PTL. The titanium felt layer has larger pores (50-200 μm) for efficient mass transport, while the sintered titanium powder layer has smaller pores (1-10 μm) for better electrical conductivity. This spatial variation in pore quality allows the structure to simultaneously achieve high permeability and good conductivity.
Solution Approach 2:
The patent transitions from a single-layer structure to a multi-layered configuration with varying pore sizes and structures. The vertical arrangement of layers with different pore characteristics (felt layer with large pores, powder layer with small pores) creates a gradient structure that optimizes both mass transport in the through-plane direction and electrical conductivity in the in-plane direction, effectively resolving the contradiction through dimensional organization.
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 approach results in improved conductivity, porosity, and mass transport efficiency, reducing contact resistance and corrosion, thereby enhancing the overall performance and durability of PEMWE systems while minimizing the need for anti-corrosion coatings and reducing manufacturing costs.
Implementation Method 1
sintering or diffusion bonding the porous transport layer and the flow field plate, therein forming a uniform or homogeneous mixing at an interface
Implementation Method 2
a combination of titanium fiber felt and titanium powder layers, with subsequent sintering and laser treatment
Implementation Method 3
a combination of titanium fiber felt and titanium powder layers, with subsequent sintering and laser treatment to create a uniform interface
Data Source
AI summary
The following disclosure relates to electrochemical or electrolysis cells and components thereof, specifically porous transport layers within electrochemical cells and methods of making such layers. In one particular example, a method of forming a portion of an electrochemical cell includes providing a porous transport layer, placing a flow field plate adjacent to a surface of the porous transport layer, and sintering or diffusion bonding the porous transport layer and the flow field plate, therein forming a uniform or homogeneous interface between the porous transport layer and the flow field plate.