Liquid / gas permeable silver-plated diffusion plate with innovative PORE geometry produced by selective laser melting method

Abstract

The invention relates to a silver-plated diffusion plate with an innovative pore geometry produced by selective laser melting method for use as a liquid / gas permeable diffusion plate in Proton Exchange Membrane cells for the production of energy and high purity hydrogen in fuel cells and electrolyzers.

Description

[0001] LIQUID / GAS PERMEABLE SILVER-PLATED DIFFUSION PLATE WITH INNOVATIVE PORE GEOMETRY PRODUCED BY SELECTIVE LASER MELTING METHOD

[0002] TECHNICAL FIELD

[0003] The invention relates to a silver-plated diffusion plate with an innovative pore geometry produced by selective laser melting method for use as a liquid / gas permeable diffusion plate in Proton Exchange Membrane cells for the production of energy and high purity hydrogen in fuel cells and electrolyzers.

[0004] PRIOR ART

[0005] One of the main shortcomings of diffusion plates used in PEM (Proton Exchange Membrane) fuel cells is the inhomogeneity of gas distribution. This problem is a critical factor that directly affects the efficiency and performance of the fuel cell.

[0006] The main task of diffusion plates is to uniformly distribute the reactive gases (hydrogen and oxygen) on the electrode surface. However, deficiencies in the design or production process of the plates can lead to uneven distribution of gases on the electrode surface. This can lead to reduced fuel cell performance, locally high current densities, and shortened material lifetime.

[0007] Water production is a major problem in PEM fuel cells. Diffusion plates must ensure both the removal of water produced during the reaction and that the membrane remains moist. However, some diffusion plates are unable to manage water effectively, which can lead to flooding or drying of the membrane. In both cases, cell efficiency decreases.

[0008] The diffusion plates also serve to collect the electric current. Poor electrical conductivity or uneven surface contact can reduce current collection efficiency. This leads to energy loss and increased intracellular resistance. OBJECTIVE OF THE INVENTION

[0009] The object of this invention is to enable precise control of the porous structure of diffusion plates at the micro scale by selective laser melting (SLM) method. This allows the gases (hydrogen and oxygen) to reach the electrode surface more homogeneously. The pore size, pore geometry, and distribution of SLM-produced plates allow for a more even distribution of reactive gases and avoid the formation of "dead zones" in the reaction zones, increasing the efficiency of the fuel cell.

[0010] Another object of the invention is to provide fast and efficient dispersion of gases by adjusting the pores to the desired geometry, density, and size. This allows the gases to reach the reaction area more efficiently and minimizes differences in reactivity at different points in the cell. As a result, a more balanced current density is achieved.

[0011] In PEM fuel cells, diffusion plates also allow the water produced during the reaction to be removed from the electrode surface. The porous plates produced by the SLM method subject to this invention have an optimized pore structure that supports the controlled removal of water. This protects cell performance by reducing the risk of flooding. In addition, porous diffusion plates allow water vapor to move smoothly between the electrodes to maintain the membrane's moisture balance. The precise production processes enabled by SLM make moisture management more efficient, thus avoiding problems such as membrane drying.

[0012] Diffusion plates produced by the SLM method within the scope of the invention can be designed to provide optimum pore structure as well as high conductivity. This increases the current collection capacity of the diffusion plate by reducing electrical resistance losses. Laser treatment of the surface also contributes to more efficient plate-electrode contact.

[0013] LIST OF DRAWINGS

[0014] Fig. 1a. Diffusion plate comprising pore channels with square geometry

[0015] Fig. 1a1. A Detail View

[0016] Fig. 1b. Diffusion plate comprising pore channels with hexagonal geometry

[0017] Fig. 1b1. B Detail View Fig. 1c. Diffusion plate comprising pore channels with circular geometry

[0018] Fig. 1c1. C Detail View

[0019] Fig. 2. Silver plating layer to increase electrical conductivity to enhance the performance of the diffusion plate in the PEM cell

[0020] References for the numbering given in the figures:

[0021] 1. Silver-plated outer surface

[0022] DETAILED DESCRIPTION OF THE INVENTION

[0023] The invention relates to a silver-plated diffusion plate with an innovative pore geometry produced by Selective Laser Melting method. Said pore geometry can be at least one of square, hexagonal, and circular forms. The pore structure in the shape of at least one of these forms is continuous throughout the section. The size of the defined pores is 300 pm and the plate porosity is at least 30%.

[0024] Selective Laser Melting (SLM) method is an additive manufacturing technology in which metal powders are melted with the help of a laser and combined into layers, resulting in a solid object. This method makes it possible to produce metal parts directly from 3D CAD (Computer Aided Design) models. One of the biggest advantages of SLM is that parts with complex geometries can be produced even in circumstances where they are difficult or impossible to produce using conventional methods. This significantly increases design freedom. It also speeds up product development processes by enabling rapid prototyping, allowing testable prototypes to be created in less time. SLM saves material by using only the metal powders needed, which reduces waste and offers a more sustainable production method.

[0025] Parts produced with Selective Laser Melting technology have high strength and durability. Laser melting process improves the mechanical properties of the structure by creating strong bonds between the layers. Another important advantage of this method is that each part can be customized according to user demands. This is particularly important for personal use products such as medical devices and implants. SLM also enables parts requiring complex assembly to be produced in a single step as a single piece, eliminating post-production assembly processes and offering time and cost savings. This technology, which can be used with various metals such as stainless steel, titanium, and aluminum, has a wide range of materials and finds use in different sectors. Especially used in the aerospace, automotive, medical, and defense industries, SLM stands out as an ideal method for producing high-strength and lightweight structures.

[0026] The first embodiment of this invention, diffusion plates with a square pore structure, shows an effective performance in directing gas and liquid flow. The smooth and regular structure of this geometry ensures homogeneous distribution of gas and liquid across the plate. The square cross-section pore structure creates the necessary flow channels for liquid and gas flow in PEM fuel cells. Thus, diffusion is easily ensured. The porous material is first designed in 3-dimensional design programs and then obtained by melting and combining metallic powders with SLM method. These plates are used in PEM fuel cells for the uniform distribution of reactive gases on the surface.

[0027] The second embodiment of this invention, the hexagonal pore structure, has a honeycomb-like structure, which provides high mechanical strength and efficient gas / liquid distribution for diffusion plates. The hexagonal geometry is particularly useful for optimizing gas and liquid flow while maintaining structural integrity. Hexagonal structures provide more surface area in the same volume, improving gas distribution and transfer efficiency. This is important for more efficient energy production in PEM fuel cells.

[0028] The circular pore structure, another embodiment of this invention, ensures homogeneous distribution of gases and liquids across the diffusion plate. With its ability to provide an even distribution of the flow, it allows a more balanced passage of liquid phases in particular. In addition, the absence of sharp corners does not allow the formation of external regions where stress and current density increase. Circular pores provide a homogeneous distribution in gas dispersion thanks to their symmetrical structure. This feature helps to distribute the gases more effectively in the PEM fuel cell, which increases the efficiency of the cell.

[0029] Silver is a material with very high electrical conductivity. Within the scope of this invention, plating it on the surface of the diffusion plate provides a more efficient transmission of electric current. This increases the efficiency of electrochemical reactions, especially in applications such as fuel cells. Electrical performance is improved due to the plating reducing the contact resistance between the electrodes and the gas diffusion layer. The silver plating helps regulate gas and liquid flow by optimizing the surface structure of the diffusion plate. By providing a uniform surface structure, the plating ensures homogeneous distribution of gases and liquids on the plate surface and allows reactive substances to diffuse evenly at each point. The plating referred to within the scope of the invention is electroless silver plating. The electroless silver plating method allows a homogeneous and thin coating to be applied on complex geometries and porous structures, since no electric current is used. This prevents the porous structures from breaking down during plating and ensures that all surfaces are evenly coated. The electroless silver plating process is applied in thin layers, minimizing the weight of the diffusion plate and maintaining its lightweight structure. The thickness of the plating is in the range of 1-5 pm.

Claims

CLAIMS1. A diffusion plate produced by the Selective Laser Melting (SLM) method, characterized in that it has a pore structure in at least one of the square, hexagonal, and circular shapes and has a silver-plated outer surface.

2. The diffusion plate according to claim 1 , characterized in that the pore structure in the form of at least one of a square, hexagonal, and circular shape is continuous throughout the cross-section.

3. The diffusion plate according to claim 1 or 2, characterized in that the pore size is 300 pm.

4. The diffusion plate according to any one of claims 1 - 3, characterized in that it has a porosity of at least 30%.

5. The diffusion plate according to claim 1 , characterized in that the silver plating of the outer surface thereof is electroless.

6. The diffusion plate according to claim 1 or 5, characterized in that the silver plating thickness is in the range of 1-5 pm.

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