Cell design for optimised use of expanded-metal porous transport layers in electrolysis
The cell design for electrolysis uses clamped microgrid expanded metal sheets to address warping and welding issues, enabling smaller pore sizes and cost-effective fluid conductivity without pore closure.
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- SIEMENS ENERGY GLOBAL GMBH & CO KG
- Filing Date
- 2025-11-21
- Publication Date
- 2026-07-16
AI Technical Summary
Current electrolyzer designs face challenges with microgrid expanded metal sheets due to internal stresses causing warping and curling, which prevent the use of smaller pore sizes, and welding these sheets to a substructure leads to pore closure, impairing fluid conductivity and increasing costs.
A cell design that clamps microgrid expanded metal sheets between divided frames, eliminating the need for welding by using screws, pins, or adhesive to secure the sheets, allowing smaller pore sizes without pore closure.
Enables smaller pore sizes with improved fluid conductivity and cost-effectiveness compared to sintered materials, while avoiding welding-related issues and maintaining electrical contact with the MEA.
Smart Images
Figure EP2025083837_16072026_PF_FP_ABST
Abstract
Description
[0001] 2024PF00698
[0002] 1
[0003] Description
[0004] Cell design for the optimized use of expanded metal PTLs in electrolysis
[0005] The invention relates to a cell design for the optimized use of expanded metal sheets in electrolysis.
[0006] In current electrolyzer designs, the anode GDL (Gas Diffusion Layer) uses a microgrid expanded metal sheet welded to a coarser-mesh expanded metal substructure. The microgrid provides electrical and mechanical contact to the membrane electrode assembly (MEA) and conducts fluids to and from the MEA. To optimally perform these functions, the microgrid should have the finest possible mesh to ensure complete electrical contact with the MEA over its entire surface. However, the pores must be large enough to allow fluids to flow through unimpeded or without excessive resistance.
[0007] Currently available microgrids have pore sizes of approximately .
[0008] 0.6 mm to 0.45 mm. The trend is towards using increasingly smaller mesh sizes.
[0009] As an alternative to expanded metal, fiber- or powder-based sintered materials can be used, where pore sizes of approximately 0.05 mm to 0.05 mm can be achieved.
[0010] These alternatives to microgrid expanded metal sheets are, as already mentioned, generally sintered. This allows these structures to lie very flat on a surface and be placed in an electrolysis cell without being welded to the substructure. However, these structures are significantly more expensive than microgrids. 2024PF00698
[0011] 2
[0012] Direct insertion into a cell is not possible with microgrid expanded metal. The stretching process creates internal stresses in the material, which could cause the expanded metal to warp significantly and curl up.
[0013] Therefore, the expanded metal sheet is currently welded to the substructure. It then lies flat on the expanded metal substructure and is bonded to it. In principle, it would also be possible to reduce the residual stresses in the expanded metal sheet; however, this would require a soft annealing and straightening process, which is not cost-effective.
[0014] If expanded metal with reduced pore size is used, welding problems arise. The pores of the expanded metal close up, and the fluid conductivity is either lost or severely impaired.
[0015] It is therefore the purpose of the invention to solve the problem mentioned above.
[0016] The problem is solved by a cell design according to claim 1.
[0017] The subclaims list further advantageous measures which can be combined arbitrarily to achieve further synergy effects.
[0018] They show
[0019] Figure 1 shows a first embodiment and
[0020] Figure 2 shows a second embodiment.
[0021] The figures and description represent only exemplary embodiments of the invention. 2024PF00698
[0022] 3
[0023] A frame of a cell 1, 1 ' for electrolysis is modified so that the microgrid expanded metal sheet can be clamped here.
[0024] Several approaches are suitable for this.
[0025] Figure 1 shows a first embodiment. A cell frame 5 - preferably an injection-molded part between the bipolar plates - is preferably divided in the middle.
[0026] Other manufacturing processes such as milling are also conceivable. This division allows not only the MEA 13 to be clamped between the cell frames, but also the microgrid expanded metal sheet 10.
[0027] The cell frame 5 is divided into a lower cathode frame 4 and an upper anode frame 7.
[0028] Therefore, a seal 16 is preferably used between the two frame parts 4, 7 .
[0029] The frame parts 4, 7 are designed such that a slot 9 is formed between them when the frame parts 4, 7 are brought together, into which the microgrid 10 and the MEA 13 can be inserted.
[0030] The microgrid 10 is fixed by a screw 17 or similar, in particular located in the frame part 7. Instead of the screw, for example an electrolysis-resistant adhesive or a pin on the frame, into which the expanded metal sheet can be "clipped", can also be used.
[0031] Preferably, four such fixings 17, in particular screws, are required in the ends of the preferably rectangular cell frame 5. 2024PF00698
[0032] 4
[0033] Figure 2 shows another variant in which the frame 5 ' does not have a slot 9, but is preferably divided in the middle and stepped 26.
[0034] The arrangement of microgrid 10 and MEA 13 is similar or the same as in Figure 1.
[0035] A pin 24 or a screw 24 is present in a frame part of the frame 5 '. Preferably in the frame part 4 that forms the step 26 .
[0036] These clamping mechanisms of the microgrid 10 eliminate the need for welding to a substructure.
[0037] As a result, smaller pore sizes are possible (which would otherwise clog during welding). This allows for a similar porosity to that of sintered materials, but the expanded metal sheet is significantly cheaper.
[0038] Overall, the following advantages result:
[0039] - Smaller mesh size possible
[0040] - No risk of the pores in the expanded metal sheet becoming "sealed shut" - Simpler welding process for the expanded metal substructure and no quality control required with regard to clogged pores
[0041] - More economical design with the same "fineness" of the contact layer compared to sintered products.
Claims
2024PF00698 Patent claims 1. cell ( 1 , 1 ' ) for an electrolyzer which has a frame ( 5 , 5 ' ) , in which a sheet metal substructure ( 19 ) for the anode , a microgrid ( 10 ) , a MEA ( 13 ) as well a further expanded metal sheet assembly cathode ( 22 ) is arranged, characterized in that the frame ( 5 , 5 ' ) is constructed or divided in such a way that the microgrid ( 10 ) is clamped onto or through the frame ( 4 , 7 , 4 ' , 7 ' ).
2. Cell according to claim 1 , wherein the clamping is effected by a pin ( 17 , 24 ) or screw ( 17 , 24 ) in a part ( 4 , 7 ) of the frame ( 5 , 5 ' ).
3. Cell according to claim 1 or 2 , in which the frame ( 5 ) is divided into a cathodic and anodic part ( 4 , 7 ) such that a slot ( 19 ) is formed , in which the microgrid ( 10 ) and the MEA ( 13 ) are inserted and fixed, in particular by a pin ( 17 , 24 ) or screw ( 17 , 24 ) .
4. Cell according to claim 1 or 2 , where the frame ( 5 ' ) is divided into a cathodic and an anodic part ( 4 ' , 7 ' ), that a paragraph ( 26 ) is formed, on which the microgrid ( 10 ) and the MEA ( 13 ) are placed 2024PF00698 6 and can be fixed.
5. Cell according to claim 1, 2, 3, or 4, in which the pin ( 17 , 24 ) or the screw ( 17 , 24 ) is arranged in the cathodic part or in the anodic part of the frame .