Differential-Pressure Electrolysis Cell Sealing for Membrane Stability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing electrochemical cells, particularly those using membrane electrode assemblies, face challenges in adapting to high pressures due to mechanical stress and sealing issues, especially when operating under differential pressures, which can lead to membrane distortion and leakage.
Innovation Solution
The electrochemical cell design incorporates a porous support surrounded by a seal on both sides of the membrane, with a compressible support on the high-pressure side and an incompressible support on the low-pressure side, along with a supplementary seal to contain gases and prevent membrane distortion, allowing for efficient operation at pressures up to 40 bar or more.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the electrolysis cell operates at high differential pressure, then hydrogen production efficiency is improved, but membrane distortion and sealing reliability deteriorate
Solution Approach 1:
The seal structure is designed with different properties in different regions: a first seal portion contacts the membrane with compliance to accommodate distortion, while a second seal portion contacts the flow field plate with structural support. This local differentiation allows the seal to maintain reliability under high differential pressure while permitting the membrane to function efficiently.
Solution Approach 2:
The seal comprises a composite structure with a first seal portion and a second seal portion having different material properties. The first portion is designed to be compliant with the membrane, while the second portion provides rigid support against the flow field plate. This composite approach enables the seal to simultaneously handle membrane distortion and maintain sealing integrity under high pressure.
2Productivity
If the electrolysis cell operates at high differential pressure, then hydrogen production efficiency is improved, but membrane distortion increases
Solution Approach 1:
The seal is positioned and designed to preemptively counteract the distorting effect of differential pressure on the membrane. By contacting the membrane at its edge and providing a sealing force, the seal prevents the membrane from distorting into the gap between the porous support and flow field plate, thereby maintaining membrane shape stability during high-pressure operation.
Solution Approach 2:
The seal's first seal portion is designed to be compliant and flexible to conform to the membrane surface while preventing distortion. This flexible sealing approach allows the membrane to maintain its functional shape under differential pressure while the seal accommodates minor variations through its compliance.
3Reliability
If a non-porous gas diffusion layer is used to seal, then sealing is improved, but adaptability to high pressure deteriorates
Solution Approach 1:
Rather than making the entire gas diffusion layer non-porous, the invention uses a seal structure that provides sealing at the edge where the porous support meets the flow field plate. This localized sealing approach maintains the porous structure's adaptability to high pressure while achieving reliable sealing where needed.
Solution Approach 2:
The seal acts as an intermediary element between the porous support and the flow field plate, providing the sealing function that would otherwise require a non-porous structure. This intermediary seal allows the porous support to remain adaptable to high pressure while achieving the necessary sealing integrity.
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 effectively prevents membrane distortion and ensures reliable sealing, reducing the risk of leaks and enhancing the operational efficiency of the cell under differential pressure conditions, making it suitable for high-pressure hydrogen production without the need for excessive energy consumption.
Implementation Method 1
The low pressure side of the membrane is supported by a relatively incompressible porous support, for example sintered titanium
Implementation Method 2
The seal on the high-pressure side spans a gap between the porous support and the seal on the low-pressure side
Implementation Method 3
In an energy storage application, producing hydrogen at 60-80 bar may allow hydrogen to be injected into a regional natural gas pipeline without further compression
Data Source
AI summary
An electrochemical cell has a membrane located between two flow field plates. On a first side of the membrane, there is a porous support surrounded by a seal between the membrane and the flow field plate. There is a gap between the porous support and the seal at the surface of the membrane. On a second side of the membrane, there is a seal between the membrane and the flow field plate located inside of the gap in plan view. The electrochemical cell is useful, for example, in high pressure or differential pressure electrolysis in which the second side of the membrane will be consistently exposed to a higher pressure than the first side of the membrane.