Flexible Electrolyser Cell Frame for Uniform MEA Compression
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Solution Overview
Problem
Current electrolyser stack designs face inefficiencies due to high ohmic resistance from carbon fleeces, inadequate contact pressure on membrane electrode assemblies, and tolerance-related issues affecting compression and performance.
Innovation Solution
The design incorporates a cell frame made of plastic polymer and expanded metal layers to achieve comparable stiffness with inner components, eliminating carbon fleeces and ensuring sufficient contact pressure, while using expanded metal for flexibility and interlocking, and bipolar plates for structural support and heat dissipation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a stiff cell frame is used to maintain structural integrity, then mechanical strength is improved, but compression control and contact pressure distribution deteriorate
Solution Approach 1:
The cell frame transitions from a stiff structure to a flexible one by changing material parameters. The flexible cell frame has a stiffness of 1-100 N/mm, compared to conventional stiff frames, allowing it to deform elastically during compression to accommodate tolerances and distribute contact pressure uniformly across the MEA.
Solution Approach 2:
The cell frame is constructed from composite materials including polypropylene (PP), polyethylene (PE), or elastomers, which provide both sufficient mechanical strength and required flexibility. This composite approach maintains structural integrity while enabling controlled deformation under compression loads.
2Adaptability or versatility
If carbon fleeces are used to counterbalance tolerances, then assembly flexibility is improved, but electrical conductivity deteriorates
Solution Approach 1:
The flexible carbon fleece layer is completely removed from the assembly. Instead, the flexibility function is transferred to the flexible cell frame itself, which accommodates tolerances through elastic deformation. This elimination of carbon fleeces removes the electrical resistance barrier while maintaining assembly flexibility.
Solution Approach 2:
The flexible cell frame acts as an intermediary element between the rigid bipolar plates and the MEA, absorbing tolerance variations through its elastic properties. This mediator function previously performed by carbon fleeces is now achieved through the frame's mechanical compliance, enabling direct electrical contact without resistive layers.
3Stress or pressure
If excessive compression is applied to achieve contact pressure, then contact pressure is improved, but bipolar plate deformation increases
Solution Approach 1:
The system utilizes the flexible cell frame's elastic properties to distribute compression forces uniformly. The frame's controlled flexibility (stiffness 1-100 N/mm) prevents stress concentration on bipolar plates while ensuring adequate contact pressure on the MEA, achieving optimal compression without excessive force.
4Adaptability or versatility
If a flexible cell frame is used to accommodate tolerances, then assembly adaptability is improved, but structural strength deteriorates
Solution Approach 1:
The cell frame employs composite materials (PP, PE, elastomers) that provide both flexibility for tolerance accommodation and sufficient mechanical strength for structural support. These materials exhibit viscoelastic properties that enable reversible deformation while maintaining load-bearing capacity throughout the electrolyser stack.
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 reduces ohmic resistance, enhances contact pressure control, improves cell performance, and increases stability and durability by minimizing deformation and overheating risks, resulting in a more efficient and compact electrolyser stack.
Implementation Method 1
a first stiffness of the cell frame is at most twice as high as a second stiffness of a combination of membrane electrode assembly and the first and second gas diffusion layers
Implementation Method 2
in a lateral direction by the frictional locking between the cell frame and the bipolar plate
Implementation Method 3
The catalyst ensures that the reaction at the electrode takes place more efficiently by reducing the required activation energy
Implementation Method 4
a proton exchange membrane is arranged between two electrodes in which a catalyst is embedded
Implementation Method 5
A Gas Diffusion Layer (GDL) is a key component in the electrochemical cell for an electrolyser stack that facilitates the transport of fluids involved in the reaction
Implementation Method 6
The tie rods, with the help of endplates, compress the cell frame (plastic polymer) and inner components (GDLs and MEA)
Data Source
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AI summary
The invention is about an electrochemical cell (1) comprising: a membrane electrode assembly (2) comprising an electrolyte layer (3) and first and second electrode layers (4, 5) disposed on opposite major surfaces (6) of the electrolyte layer (3), first and second gas diffusion layers (7, 8) disposed directly on opposite major surfaces (9) of the membrane electrode assembly (2), and a cell frame (10) formed around a periphery (11) of the membrane electrode assembly (2) and the first and second gas diffusion layers (7, 8), wherein in uncompressed state a thickness of the cell frame (10) in a stacking direction (12) of the layers (3, 4, 7, 8) is smaller than a thickness of the membrane electrode assembly (2) and first and second gas diffusion layers (7, 8) combined, and a first stiffness of the cell frame (10) is at most twice as high as a second stiffness of a combination of membrane electrode assembly (2) and the first and second gas diffusion layers (7, 8). The invention further relates to an electrolyser stack (17) comprising a plurality of electrochemical cells (1).