CN112740448A - Method for producing a membrane electrode unit for a fuel cell - Google Patents
Method for producing a membrane electrode unit for a fuel cell Download PDFInfo
- Publication number
- CN112740448A CN112740448A CN201980061679.6A CN201980061679A CN112740448A CN 112740448 A CN112740448 A CN 112740448A CN 201980061679 A CN201980061679 A CN 201980061679A CN 112740448 A CN112740448 A CN 112740448A
- Authority
- CN
- China
- Prior art keywords
- component
- particles
- electrode unit
- membrane electrode
- carried out
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 239000012528 membrane Substances 0.000 title claims abstract description 65
- 239000000446 fuel Substances 0.000 title claims abstract description 33
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 21
- 239000002245 particle Substances 0.000 claims abstract description 94
- 239000000463 material Substances 0.000 claims abstract description 48
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims abstract description 38
- 239000000203 mixture Substances 0.000 claims abstract description 34
- 239000002033 PVDF binder Substances 0.000 claims abstract description 33
- 229920002981 polyvinylidene fluoride Polymers 0.000 claims abstract description 33
- 229910052799 carbon Inorganic materials 0.000 claims abstract description 22
- 229910002804 graphite Inorganic materials 0.000 claims abstract description 21
- 239000010439 graphite Substances 0.000 claims abstract description 21
- 238000002156 mixing Methods 0.000 claims abstract description 17
- 238000009792 diffusion process Methods 0.000 claims abstract description 14
- 238000005096 rolling process Methods 0.000 claims abstract description 9
- 229920001343 polytetrafluoroethylene Polymers 0.000 claims description 26
- 239000004810 polytetrafluoroethylene Substances 0.000 claims description 26
- 238000000034 method Methods 0.000 claims description 23
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 17
- 239000003054 catalyst Substances 0.000 claims description 15
- 239000000470 constituent Substances 0.000 claims description 15
- 238000005469 granulation Methods 0.000 claims description 13
- 230000003179 granulation Effects 0.000 claims description 13
- -1 polytetrafluoroethylene Polymers 0.000 claims description 13
- 239000002904 solvent Substances 0.000 claims description 11
- 238000001125 extrusion Methods 0.000 claims description 9
- 239000000243 solution Substances 0.000 claims description 7
- 239000007864 aqueous solution Substances 0.000 claims description 6
- 238000004898 kneading Methods 0.000 claims description 3
- 230000003197 catalytic effect Effects 0.000 claims description 2
- 238000005520 cutting process Methods 0.000 claims 1
- 238000010438 heat treatment Methods 0.000 claims 1
- 238000009490 roller compaction Methods 0.000 claims 1
- 239000000835 fiber Substances 0.000 description 16
- 239000011230 binding agent Substances 0.000 description 14
- 239000007789 gas Substances 0.000 description 14
- 239000011248 coating agent Substances 0.000 description 9
- 238000000576 coating method Methods 0.000 description 9
- 229920000642 polymer Polymers 0.000 description 7
- 230000002209 hydrophobic effect Effects 0.000 description 6
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 5
- 239000001301 oxygen Substances 0.000 description 5
- 229910052760 oxygen Inorganic materials 0.000 description 5
- 239000000725 suspension Substances 0.000 description 5
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 4
- 238000006243 chemical reaction Methods 0.000 description 3
- 238000009826 distribution Methods 0.000 description 3
- 239000010408 film Substances 0.000 description 3
- 239000004033 plastic Substances 0.000 description 3
- 230000008569 process Effects 0.000 description 3
- 239000000376 reactant Substances 0.000 description 3
- 229920000049 Carbon (fiber) Polymers 0.000 description 2
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 2
- 150000001252 acrylic acid derivatives Chemical class 0.000 description 2
- 239000000853 adhesive Substances 0.000 description 2
- 230000001070 adhesive effect Effects 0.000 description 2
- 230000002776 aggregation Effects 0.000 description 2
- 239000004917 carbon fiber Substances 0.000 description 2
- 238000001035 drying Methods 0.000 description 2
- 238000003487 electrochemical reaction Methods 0.000 description 2
- 239000008187 granular material Substances 0.000 description 2
- 239000001257 hydrogen Substances 0.000 description 2
- 229910052739 hydrogen Inorganic materials 0.000 description 2
- 239000007788 liquid Substances 0.000 description 2
- 238000011068 loading method Methods 0.000 description 2
- 238000002844 melting Methods 0.000 description 2
- 230000008018 melting Effects 0.000 description 2
- 235000011837 pasties Nutrition 0.000 description 2
- 229910052697 platinum Inorganic materials 0.000 description 2
- 239000011148 porous material Substances 0.000 description 2
- 238000005507 spraying Methods 0.000 description 2
- 239000010409 thin film Substances 0.000 description 2
- 238000009825 accumulation Methods 0.000 description 1
- 238000005054 agglomeration Methods 0.000 description 1
- 238000004220 aggregation Methods 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 230000008020 evaporation Effects 0.000 description 1
- 238000001704 evaporation Methods 0.000 description 1
- 238000005243 fluidization Methods 0.000 description 1
- 230000005661 hydrophobic surface Effects 0.000 description 1
- 238000010348 incorporation Methods 0.000 description 1
- 150000002500 ions Chemical class 0.000 description 1
- 239000006193 liquid solution Substances 0.000 description 1
- 239000006194 liquid suspension Substances 0.000 description 1
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 1
- 239000005518 polymer electrolyte Substances 0.000 description 1
- 238000003825 pressing Methods 0.000 description 1
- 238000005245 sintering Methods 0.000 description 1
- 125000006850 spacer group Chemical group 0.000 description 1
- 238000007725 thermal activation Methods 0.000 description 1
- 230000007704 transition Effects 0.000 description 1
- 238000009736 wetting Methods 0.000 description 1
Images
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M8/00—Fuel cells; Manufacture thereof
- H01M8/02—Details
- H01M8/0202—Collectors; Separators, e.g. bipolar separators; Interconnectors
- H01M8/023—Porous and characterised by the material
- H01M8/0241—Composites
- H01M8/0243—Composites in the form of mixtures
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M8/00—Fuel cells; Manufacture thereof
- H01M8/02—Details
- H01M8/0202—Collectors; Separators, e.g. bipolar separators; Interconnectors
- H01M8/023—Porous and characterised by the material
- H01M8/0234—Carbonaceous material
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M8/00—Fuel cells; Manufacture thereof
- H01M8/02—Details
- H01M8/0202—Collectors; Separators, e.g. bipolar separators; Interconnectors
- H01M8/023—Porous and characterised by the material
- H01M8/0239—Organic resins; Organic polymers
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M8/00—Fuel cells; Manufacture thereof
- H01M8/10—Fuel cells with solid electrolytes
- H01M8/1004—Fuel cells with solid electrolytes characterised by membrane-electrode assemblies [MEA]
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M8/00—Fuel cells; Manufacture thereof
- H01M8/10—Fuel cells with solid electrolytes
- H01M2008/1095—Fuel cells with polymeric electrolytes
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/30—Hydrogen technology
- Y02E60/50—Fuel cells
Landscapes
- Chemical & Material Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Engineering & Computer Science (AREA)
- Manufacturing & Machinery (AREA)
- Sustainable Development (AREA)
- Sustainable Energy (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Composite Materials (AREA)
- Inert Electrodes (AREA)
- Fuel Cell (AREA)
Abstract
The invention relates to a method for producing a membrane electrode unit (MEA) for a fuel cell (100) having an electrode unit (MPL) which is designed for use as a Gas Diffusion Layer (GDL), comprising the following steps: 1) providing a particle-shaped component (a, b): a) carbon particles and/or graphite particles, b) particles containing polyvinylidene fluoride (PVDF), 2) mixing at least part of component a) with component b) until component b) adheres to the particles of component a), 3) mixing the premix obtained in step 2) with the remainder of component a), 4) rolling or extruding the mixture obtained in step 3) into a strip-shaped material forming the electrode unit (MPL).
Description
Technical Field
The invention relates to a method for producing a membrane electrode unit for a fuel cell according to the independent method claim. Furthermore, the invention relates to a corresponding membrane electrode unit according to the independent device claim. The invention further relates to a corresponding fuel cell according to the parallel independent device claim.
Background
Fuel cells are electrochemical transducers. In polymer electrolyte membrane fuel cells or PEM fuel cells for short, the reactants hydrogen and oxygen are converted to water, electrical energy and heat in order to obtain energy. According to the prior art, PEM fuel cells are constructed as a stack of repeating units comprising a cathode region, a bipolar plate, an anode region and a membrane electrode unit. The bipolar plates are electrically conductive but impermeable to gases and ions. The bipolar plate distributes, for example, hydrogen in the anode region and oxygen or air in the cathode region by means of a spacer structure in the millimeter range. In order to simplify the transition and distribution of the gas from the millimeter-scale structured portion of the bipolar plate to the nano-scale catalyst particles of the membrane electrode unit, a porous intermediate layer (e.g. gas diffusion layer, GDL) between the bipolar plate and the membrane electrode unit is required. The intermediate layer can be configured, for example, as a porous fiber web made of carbon fibers. The fiber ends of the carbon fibers can thereby be erected perpendicular to the surface of the intermediate layer, depending on the production.
If such a fiber web is pressed by the separator structure of the bipolar plate, the porosity under the separators is significantly reduced and especially a build-up of product water occurs under these separators. The accumulation of product water hinders the necessary diffusion of oxygen or air, especially on the oxygen or air side. Thereby limiting the local current density and the effective power of the fuel cell. In order to be able to drain water from the fibre web, some known fibre webs are provided with a hydrophobic coating. However, by applying the hydrophobic coating, for example by means of spraying, a partial or complete closure of the open porous structure may occur, so that the porous structure for draining the liquefied water narrows or is closed, although the fibrous web has the hydrophobic coating. Thereby also preventing oxygen or air from entering the membrane.
Relatively thin membranes with a material thickness of a few micrometers are currently required in fuel cells. Such membranes cannot be used as free-standing membranes or can only be used as free-standing membranes with considerable effort and high rejection rates. Therefore, these very thin films are currently coated directly onto one side of the web. Since the fiber structure on the surface of the fiber web is uneven, a corrugated membrane can be constructed. The corrugated membrane does not achieve good contact with the gas diffusion layer on the corresponding side. The fiber web is often coated with a microporous layer that is also attached to the fiber web by spraying, drying and sintering of the particle suspension. Here, the surface wave shape of the web is followed by the application process. Furthermore, when the fiber web is directly coated with a particle suspension or a membrane solution forming a membrane, the solution or suspension can be forced into the recesses of the fiber structure and fill these recesses. The solution or suspension thus squeezed in can close the porous structure of the gas diffusion layer and impede the gas flow and the water discharge. Furthermore, such membranes or microporous layers can have a non-uniform thickness and thus cause a non-uniform resistance. Locally different current intensities can thereby occur, as a result of which the effective power of the fuel cell can be limited.
Disclosure of Invention
The invention provides a method for producing a membrane electrode unit for a fuel cell according to the independent method claim. The invention also provides a corresponding membrane electrode unit according to the independent device claim. Furthermore, the invention provides a corresponding fuel cell according to the parallel independent device claim. Further advantages and details of the invention emerge from the dependent claims, the description and the drawings. The advantages, features and details described in connection with the method according to the invention are of course also applicable here to the membrane electrode unit according to the invention and to the fuel cell according to the invention and vice versa, so that the disclosures in respect of the various aspects of the invention are always or can be mutually referred to.
The invention provides a method for producing a membrane electrode unit for a fuel cell having an in particular microporous electrode unit, wherein the in particular microporous electrode unit is designed for use as a gas diffusion layer, having the following steps:
1) providing a particulate form of components (a, b):
a) the carbon particles and/or the graphite particles,
b) particles containing polyvinylidene fluoride (PVDF),
2) mixing at least part of component a) with component b) until component b) adheres to the particles of component a),
3) mixing the premix obtained in step 2) with the remainder of component a),
4) rolling or extruding the mixture obtained in step 3) into a strip-shaped material forming said electrode unit (MPL).
Within the framework of the invention, a membrane electrode unit is understood to be a particularly microporous electrode unit which can have a catalyst material for electrochemical reactions, for example platinum, and which can be coated with an ion-conducting membrane. Within the framework of the invention, the particularly microporous electrode unit can be used as a gas diffusion layer with or without a separate fiber-based intermediate layer. Within the framework of the invention, the electrode unit, in particular microporous, has a significantly flatter surface than a fiber-based gas diffusion layer or than a particle-based microporous layer applied directly to a fiber web. Within the framework of the invention, the, in particular microporous, electrode unit is advantageously suitable for coating with a film sheet having a material thickness of a few micrometers, which forms a uniform, advantageously planar layer on the surface of the, in particular microporous, electrode unit according to the invention. Within the framework of the invention, the electrode unit, which is in particular microporous, has a pore structure in the nanometer range and a material thickness of 10 μm to 150pm, preferably 20 μm to 70 μm. Component a) is used for the electrical conductivity of the finished electrode unit. Component b) acts as a binder and/or hydrophobic coating for the particles of component a).
For fuel cell electrodes a high content of hydrophobic surfaces is required, which can be obtained in the form of a mixture by adding polymers, such as polyvinylidene fluoride (PVDF) and/or Polytetrafluoroethylene (PTFE). These hydrophobic components must be homogeneously distributed in the mixture and fixed by carbon and/or graphite particles.
The idea of the invention is that a polymer, such as polyvinylidene fluoride (PVDF) (component b)), optionally mixed with Polytetrafluoroethylene (PTFE) (component c) and electrically conductive particles, such as carbon particles and/or graphite particles (component a)), which can have the same density and particle size, for example, by fluidization in an air stream, is intensively and rapidly mixed. The fixing of these mixtures is effected in step 2) and/or step 3) by thermal activation, i.e. melting of the polymer, if appropriate by wetting with a binder solution or binder suspension in an optional step 2 a). The mixture produced had more and more aggregates from step 2) to step 3). Within the framework of the invention, the mixture comprises a plastic-based binder, in particular polyvinylidene fluoride-containing Particles (PVDF), which are particularly advantageous for continuous mixtures which can be processed in an advantageous manner to thin (advantageously ductile) strip-shaped materials having a material thickness of 10 μm to 150 μm, preferably 20 μm to 70 μm. Within the framework of the invention, the particles of carbon particles and/or graphite particles are gradually pre-granulated in steps 2) and 3) into granules of carbon particles and/or graphite particles. According to the invention, it is possible to produce thin strip-shaped materials from the mixture provided in step 5) by means of an extrusion or rolling process, which can form the basis of membrane electrode units for fuel cells, by means of particles containing polyvinylidene fluoride (PVDF). Mechanical forces occur on and in the aggregates during rolling, which are produced by small relative movements of the graphite particles or aggregates with respect to one another. The polymer is thereby also stretched, so that additional graphite joints are produced, which are pressed onto the graphite particles by local forces and relative movements. This enables simple film formation.
Furthermore, the invention can be provided within the framework of a method for producing a membrane electrode unit that a solvent and/or water with a (corresponding) mass component of 1 to 10 wt.% is added in step 2) and/or in step 3) within the premix or mixture. Here, the solvent may contribute to liquefying component b) and may carry out a pregranulation or granulation of the particles of component a). The water can in turn result in the particles of component a) not being damaged in steps 2) and 3). The mixture provided or completed in step 3) is a continuous mixture that is neither liquid nor pasty, but that remains significantly dry because water wets only the particle surfaces, but the mixture does not fluidize due to the small amount of water. The solvent and/or water may be evaporated as much as possible in step 4). In principle, it is conceivable that a step for drying the web-shaped material can be provided after step 4).
Furthermore, the invention can be provided in the framework of a method for producing a membrane electrode unit in that in step 1) component b) can be provided in the form of an aqueous solution with a mass fraction of 30 to 70 wt.% in the interior of the aqueous solution. In this way, mixing of the components a) and b) and/or granulation of the particles of component a) can be facilitated.
Furthermore, the invention can be provided within the framework of a method for producing a membrane electrode unit in that in step 1) the ratio of 1: 1 to 20: 1. preferably 10: 1, and/or, in step 2), in a ratio of 4: 1 to 19: 1. preferably, 9: the mass ratio of 1 provides the constituent parts (a, b). Thus, the carbon particles and/or graphite particles (or component a) can be admixed in portions or in parts to form a premix which, with each addition of a further portion or further part of component a), has more and more carbon particles and/or graphite particles (or component a) in the finished mixture. At the same time, sufficient binder in the form of component b) remains in the finished mixture, which binder is responsible for the bonding of the finished mixture, so that it can be processed as a continuous mixture into a strip-shaped material.
Furthermore, the invention can be provided in the context of a method for producing a membrane electrode unit in that polytetrafluoroethylene Particles (PTFE) are admixed to component b) in step 1) and/or in that in step 1) a flow rate of 1: 1 to 5: 1. preferably 1: a mass ratio of 1 provides polyvinylidene fluoride Particles (PVDF) and polytetrafluoroethylene Particles (PTFE). Polytetrafluoroethylene Particles (PTFE) are used in an advantageous manner as binders which deform plastically and can thus be brought into good contact with the particles and thus maintain particle contact even under mechanical loading, that is to say stretch between the particles under mechanical loading. Polyvinylidene fluoride Particles (PVDF) are used in an advantageous manner as binders which are sufficiently stable to be able to be processed into thin, elastic films. With a corresponding ratio between polyvinylidene fluoride Particles (PVDF) and polytetrafluoroethylene Particles (PTFE), a good combination of adhesive and tensile strength is achieved for the production and processing into strip-shaped materials with relatively small material thicknesses of 20 to 70 μm.
Furthermore, the invention can be provided in the context of a method for producing a membrane electrode unit in that in step 2) a pregranulation of the particles of component a) with the material of component b) takes place, and/or step 2) is carried out at a temperature >19 ℃, and/or step 2) is carried out by means of extrusion, kneading, mixing, pressing or rolling. Thus, a dry, i.e. solvent-free, premix can be produced in an advantageous manner. The conversion of the polymer structure, which is plastically processable, takes place at temperatures >19 ℃, so that pregranulation of at least part of the component a) can be achieved. At the same time, component b) remains granular in a sufficient amount so that component a) can be gradually further admixed in step 3).
Furthermore, the invention can be provided in the context of a method for producing a diaphragm electrode unit in that the granulation of the particles of component a) with the material of component b) is carried out in step 3), and/or that step 3) is carried out at a temperature of 50 ℃ to 400 ℃, in particular 150 ℃ and 240 ℃, and/or that step 3) is carried out by means of fluidized bed granulation. In an advantageous manner, therefore, a continuous mixture can be produced, which can be processed to form a strip-shaped material. At temperatures of 50 ℃ to 400 ℃, in particular 150 ℃ and 240 ℃, the binder or component b) can melt and cause granulation of the particles of component a).
In addition, the invention can be provided in the framework of the method for producing a diaphragm electrode unit that in step 4) at least one roller or extrusion worm is heated to a temperature of 50 ℃ to 400 ℃, in particular 150 ℃ and 240 ℃. Thus, evaporation of solvent and/or water, if present, may be achieved. Furthermore, flattening of the strip-shaped material can be achieved.
In addition, the invention can be provided within the framework of the method for producing a membrane electrode unit in that in a further step 5) the strip-shaped material is wetted with the aid of a catalytic solution or is coated with a catalyst layer. Thus, a catalyst layer can be formed on the surface of the strip-shaped material, which can be used for triggering a chemical reaction on the active side of the membrane.
Still and/or additionally, it is conceivable that at least a part of the particles of component a) is wetted or coated with a catalyst in step 1). In this way, it is possible to process particles with different characteristics in the premix in step 2) and in the mixture in step 3). The particles with catalyst can be used to trigger a chemical reaction on the active side of the membrane directly or without further processing of the catalyst layer on the surface of the strip-shaped material.
In addition, the invention can be provided within the framework of the method for producing a membrane electrode unit in that the strip-shaped material with the ion-conducting membrane is printed in a further step 6) as a multilayer material. Thus, a multilayer material can be provided from which ready-to-use membrane electrode units for fuel cells can be cut out.
Furthermore, the invention can be provided in the framework of the method for producing a membrane electrode unit in that in a further step 7) the multilayer material is cut into a membrane electrode unit. Thus, a ready-to-use membrane electrode unit for a fuel cell may be provided.
Furthermore, the invention provides a membrane electrode unit which is produced by means of a method which can be implemented as described above. The same advantages as described in connection with the method according to the invention are achieved by means of the membrane electrode unit according to the invention. These advantages are fully referenced herein.
The invention is also provided with a fuel cell having a membrane electrode unit which is produced by means of a method which can be carried out as described above. The same advantages as described in connection with the method according to the invention can also be achieved with the aid of the fuel cell according to the invention. These advantages are fully referenced herein.
In addition, it is conceivable in a fuel cell within the meaning of the invention to use electrode units with a membrane applied to them on the cathode side and electrode units with or without a coating with a membrane on the anode side, which can be pressed against one another, hot-pressed, glued or the like.
In addition, it is conceivable in fuel cells within the meaning of the present invention that the, in particular, microporous electrode cells can be used as gas diffusion layers without additional, for example fibrous, intermediate layers in order to simplify the distribution of the reactants from the millimetre structure of the bipolar plate to the catalyst particles on the order of nanometers of the membrane electrode cells.
Drawings
The membrane electrode unit according to the invention and the fuel cell according to the invention and its embodiments and advantages are explained in detail below with reference to the drawings. The figures each schematically show:
figure 1 is a schematic representation of the flow of the method according to the invention,
figure 2 is a schematic cross-sectional view of a membrane electrode unit in the sense of the present invention,
FIG. 3a schematic sectional illustration of a fuel cell in the sense of the invention, and
fig. 4 is an enlarged view of a schematic sectional illustration of a diaphragm electrode unit in the sense of the invention.
Identical components of the invention are always provided with the same reference numerals in the different figures, and these reference numerals are therefore usually only explained once.
Detailed Description
Fig. 1 shows a schematic flow diagram of a method for producing a membrane electrode unit MEA for a fuel cell 100 in the sense of the present invention. Fuel cell 100 comprises an electrode unit MPL, in particular with micropores, which is designed to be used as a gas diffusion layer GDL. The method comprises the following steps:
1) providing a particulate form of components (a, b):
a) the carbon particles and/or the graphite particles,
b) polyvinylidene fluoride-containing Particles (PVDF) (in other words, a mixture containing polyvinylidene fluoride, possibly with optional additional polymers, such as Polytetrafluoroethylene (PTFE) and/or acrylates),
2) mixing at least a part of component a) with component b) until component b) adheres to the particles of component a).
Step 2) is effected, for example, by mixing the components (a, b) in a fluidized-bed fluidized bed (F) or a blade mixer, preferably at elevated temperatures. Then, when the content of component b) that can achieve adhesion at elevated temperatures is higher than the desired polymer content of the strip-shaped material to be produced, a further component a) is optionally added, i.e. the premix is diluted by the further material of component a). The aggregation of the constituents (a, b) is advantageously carried out in step 2).
The invention can be arranged in an optional step 2a) as follows:
2a) the further particulate constituents c), for example polyvinylidene fluoride Particles (PVDF) and/or polytetrafluoroethylene Particles (PTFE) and/or acrylates, are premixed and/or dissolved in a continuous or discontinuous mixing process (B) in solvents and/or water. Alternatively, provision can be made in step 2a) for the incorporation of conductive carbon black (leitruru β en) for improving the electrical conductivity of the strand-shaped material to be produced.
3) Mixing the premix obtained in step 2) with the remainder of component a),
step 3) can preferably be achieved by mixing the especially liquid solution or suspension obtained in step 2a) with the premix obtained in step 2). This can take place in a fluidized-bed flow bed (F) in which the particulate constituents provided in step 2) are at least partially coated with a solution or the adhesion of the constituents a) and/or b) is improved. Advantageously, in step 3) the additional agglomeration of the particulate constituents (a, b, c) is effected by removing the solvent from the air stream of the fluidized-bed fluidized bed (F), preferably by means of the further particulate constituents c). Here, the electrical and mechanical bonding of the aggregated components is very strong and uniform. Depending on the requirements of the subsequent processing, porous or compact aggregates can be produced by means of the solvent content, the air flow rate and the mass ratio of the individual components relative to one another.
The invention can be arranged in an optional step 3a) as follows:
3a) providing a mixture of aggregates obtained in step 3),
4) rolling or extruding the mixture obtained in step 3) into a strip-shaped material, which forms or from which electrode units, in particular micro-holes, can be cut out.
In the illustration of fig. 1, two further components c) and d) are shown, which can optionally be added to the premix in step 2) and/or to the mixture in step 4). These components c) and d) are referred to in detail below.
Within the framework of the invention, a membrane electrode unit MEA is understood to be a particularly microporous electrode unit MPL which can have a catalyst material for electrochemical reactions, for example platinum, and can be coated with an ion-conducting membrane M (see fig. 4). Within the framework of the invention, in particular a microporous electrode unit MPL can be used as a gas diffusion layer GDL with or without a separate fiber-based intermediate layer (see fig. 3). Within the framework of the invention, the microporous electrode unit MPL has a significantly more uniform surface than the fiber-based gas diffusion layer GDL (see fig. 4). Within the framework of the invention, the, in particular microporous, electrode unit PML is advantageously suitable for being coated with a thin-film sheet M having a material thickness of a few micrometers, which forms a uniform, advantageously planar layer on the surface of the, in particular microporous, electrode unit MPL according to the invention (see fig. 4). Within the framework of the invention, the electrode unit MPL, in particular a micro-porous, has a pore structure in the nanometer range and a material thickness of 20 to 70 μm. Component a) is used for the conductivity of the completed electrode cell MPL. Component b) acts as a binder and/or hydrophobic coating for the particles of component a).
In steps 2) and 3), the carbon particles and/or graphite particles (or component a) can be admixed in portions or in parts to form a premix which, with each addition of a further portion or further part of component a), has an increasing number of carbon particles and/or graphite particles (or component a) in the finished mixture.
Within the framework of the invention, the mixture can have a plastic-based binder, for example polyvinylidene fluoride Particles (PVDF), as a constituent or a constituent of constituent b). Furthermore, within the framework of the invention, the mixture can have a further binder based on plastic, for example polytetrafluoroethylene Particles (PTFE), as a further optional constituent c). In this case, the invention can provide that component c) is admixed to component b) in step 1). Furthermore, the invention may be arranged such that, in step 1), the ratio by mass of 1: 1 to 5: 1. preferably 1: 1 provides polyvinylidene fluoride Particles (PVDF) and polytetrafluoroethylene Particles (PTFE). A combination of good adhesion and even good ductility for the tape-shaped material and a relatively small material thickness of 20 to 70 μm is achieved with a corresponding ratio between polyvinylidene fluoride Particles (PVDF) and polytetrafluoroethylene Particles (PTFE).
Within the framework of the invention, the particles of carbon particles and/or graphite particles are gradually pregranulated in steps 2) and 3) into a defined, for example complete granulation of the carbon particles and/or graphite particles. In step 4), the adhesive can again be stretched by mechanical movement, in order to form a larger contact surface for the graphite connection.
As can also be seen from fig. 1, in step 2) and/or step 3) a solvent and/or water can be added as a further constituent d) to the premix or mixture, for example in a (corresponding) mass fraction of 1 to 10 percent by weight within the premix or mixture. Solvents may be used to enable pre-granulation or granulation. In this case, water can again be used to protect the particles of carbon particles and/or graphite particles from damage.
Thus, in step 3) a continuous mixture can be provided which is neither liquid nor pasty, but which can be processed into a strip-shaped material in step 4), for example by means of rolling or extrusion.
The constituents b) and c) can be provided in the form of an aqueous solution in a mass fraction of (correspondingly) 30 to 70 wt.% in the interior of the aqueous solution.
Within the framework of the invention, it is conceivable that in step 1) the carbon particles and/or graphite particles are present in a ratio of 1: 1 to 20: 1. preferably 10: 1, and/or, in step 2), carbon particles and/or graphite particles are present in a mass ratio of 4: 1 to 19: 1. preferably, 9: a mass ratio of 1 is provided.
The pregranulation of the particles of component a) can be carried out in step 2) at a temperature >19 ℃. Additionally, the pregranulation can be carried out in step 2) by means of extrusion, kneading, mixing, extrusion or rolling.
In step 4), the granulation of the granules of component a) can be carried out at temperatures of from 50 ℃ to 400 ℃, in particular 150 ℃ and 240 ℃, depending on which melting temperature the binder or mixture of binders has. Here, the temperature may depend on the mixing ratio between the component b) and the component c).
As indicated in fig. 1, step 3) can be carried out by means of fluidized bed granulation. Thus, an advantageously continuous mixture can be produced, which can be processed into a strip-shaped material. The fiberization of component b) and/or component c) can advantageously be carried out by means of fluidized bed granulation and elevated temperature.
Furthermore, it can be provided within the framework of the invention that in step 4) at least one roller W1, W2 or extrusion worm E is heated to a temperature of 50 ℃ to 400 ℃, in particular 150 ℃ and 240 ℃. Here, the temperature may depend on the mixing ratio between the component b) and the component c). Thus, in step 4) it is possible to evaporate the solvent and/or water as much as possible and also to flatten the strip-shaped material.
Within the framework of the invention, it is conceivable to form the catalyst material on the surface of the finished strip-shaped material as a wet-out (Benetzung) and/or as a coating, for example in a further step 5) which is not shown.
Still and/or additionally, it is conceivable that at least a part of the particles of component a) is wetted or coated with a catalyst in step 1). In this way, the particulates with catalyst may already be present in the premix in step 2) and in the mixture in step 3).
In the framework of the method for producing the membrane electrode unit MEA, it may also be provided, for example in a further step 6), not shown, that a strip-shaped material with the ion-conducting membrane M is printed into a multilayer material from which the ready-to-use membrane electrode unit MEA (see fig. 2) for the fuel cell 100 (see fig. 3) can be cut out.
Finally, the multilayer material can be cut into membrane electrode units MEA in a further step 7), not shown. Thus, a ready-to-use membrane electrode unit MEA (see fig. 2) for the fuel cell 100 (see fig. 3) can be provided.
The invention can be provided in a fuel cell 100 in that an electrode unit MPL produced according to the invention is used on the cathode side K, which has a membrane M applied to it, and on the anode side a an electrode unit MPL produced according to the invention is used, which may or may not have a coating with a membrane M, which may be pressed against one another, hot pressed, glued or the like.
The microporous electrode unit MPL in particular can advantageously be used as a gas diffusion layer GDL without an additional, for example fibrous, intermediate layer in order to simplify the distribution of the reactants from the millimetre structure of the bipolar plate BPP to the catalyst particles on the order of nanometers of the membrane electrode unit MEA (see fig. 3).
The foregoing description of the drawings merely describes the invention in the framework of examples. Of course, the individual features of the embodiments can be freely combined with one another as far as technically expedient, without departing from the framework of the invention.
Claims (13)
1. Method for producing a membrane electrode unit (MEA) for a fuel cell (100) having an electrode unit (MPL) embodied for use as a Gas Diffusion Layer (GDL), having the following steps:
1) providing a particle-shaped component (a, b):
a) the carbon particles and/or the graphite particles,
b) particles containing polyvinylidene fluoride (PVDF),
2) mixing at least part of component a) with component b) until component b) adheres to the particles of component a),
3) mixing the premix obtained in step 2) with the remainder of component a),
4) rolling or extruding the mixture obtained in step 3) into a strip-shaped material forming said electrode unit (MPL).
2. The method of claim 1,
adding a solvent and/or water in a mass fraction of 1 to 10 percent by weight in step 2) and/or in step 3) to the respective premix or mixture.
3. The method according to any of the preceding claims,
in step 1), component b) is provided in the form of an aqueous solution in a mass fraction of 30 to 70 wt.% in the interior of the aqueous solution.
4. The method according to any of the preceding claims,
in step 1) with a ratio of 1: 1 to 20: 1 provides the constituents (a, b),
and/or, in step 2), the ratio of 4: 1 to 19: the mass ratio of 1 provides the constituent parts (a, b).
5. The method according to any of the preceding claims,
polytetrafluoroethylene Particles (PTFE) are admixed to component b) in step 1),
and/or, in step 1), the ratio of 1: 1 to 5: a mass ratio of 1 provides polyvinylidene fluoride Particles (PVDF) and polytetrafluoroethylene Particles (PTFE).
6. The method according to any of the preceding claims,
the pregranulation of the particles of component a) with the material of component b) is carried out in step 2),
and/or, step 2) is carried out at a temperature >19 ℃,
and/or step 2) is carried out by means of extrusion, kneading, mixing, extrusion or roller compaction.
7. The method according to any of the preceding claims,
granulation of the particles of component a) with the material of component b) is carried out in step 3),
and/or, step 3) is carried out at a temperature of from 50 ℃ to 400 ℃,
and/or step 3) is carried out by means of fluidized bed granulation.
8. The method according to any of the preceding claims,
heating at least one roller (W1, W2) to a temperature of 50 ℃ to 400 ℃ in step 4).
9. The method according to any of the preceding claims,
in a further step 7) the strip-shaped material is wetted with a catalytic solution or coated with a catalyst layer, and/or in step 1) at least a part of the particles of component a) is wetted or coated with a catalyst.
10. The method according to any of the preceding claims,
in a further step 6), the strip-shaped material having the ion-conducting membrane (M) is printed as a multilayer material.
11. The method according to any of the preceding claims,
cutting the multilayer material into membrane electrode units (MEAs) in a further step 7).
12. A membrane electrode unit (MEA) characterized in that,
the membrane electrode unit (MEA) is manufactured by means of a method according to any one of the preceding claims.
13. Fuel cell (100) having a membrane electrode unit (MEA) according to the preceding claim.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE102018215904.1 | 2018-09-19 | ||
| DE102018215904.1A DE102018215904A1 (en) | 2018-09-19 | 2018-09-19 | Method of manufacturing a membrane electrode assembly for a fuel cell |
| PCT/EP2019/072479 WO2020057893A1 (en) | 2018-09-19 | 2019-08-22 | Method for producing a membrane electrode assembly for a fuel cell |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN112740448A true CN112740448A (en) | 2021-04-30 |
Family
ID=67770489
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201980061679.6A Pending CN112740448A (en) | 2018-09-19 | 2019-08-22 | Method for producing a membrane electrode unit for a fuel cell |
Country Status (3)
| Country | Link |
|---|---|
| CN (1) | CN112740448A (en) |
| DE (1) | DE102018215904A1 (en) |
| WO (1) | WO2020057893A1 (en) |
Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH073484A (en) * | 1991-08-23 | 1995-01-06 | Tanaka Kikinzoku Kogyo Kk | Manufacture of gas diffusion electrode |
| US6465041B1 (en) * | 2001-12-19 | 2002-10-15 | 3M Innovative Properties Company | Method of making gas diffusion layers for electrochemical cells |
| JP2008171702A (en) * | 2007-01-12 | 2008-07-24 | Toyota Motor Corp | Manufacturing method of fuel cell assembly, manufacturing method of fuel cell, fuel cell assembly and fuel cell |
| CN101608323A (en) * | 2009-07-02 | 2009-12-23 | 昆明理工大学 | The preparation method of zero-anode-potential hydrogen-diffusion anodes |
| JP2010015832A (en) * | 2008-07-03 | 2010-01-21 | Toyota Motor Corp | Gas diffusion layer for fuel cell, and membrane-electrode assembly and fuel cell using the same |
| CN102047478A (en) * | 2008-10-31 | 2011-05-04 | 松下电器产业株式会社 | Membrane electrode assembly and fuel cell |
| US20170200954A1 (en) * | 2015-09-16 | 2017-07-13 | Uti Limited Partnership | Fuel cells constructed from self-supporting catalyst layers and/or self-supporting microporous layers |
| CN107819112A (en) * | 2016-09-13 | 2018-03-20 | 罗伯特·博世有限公司 | Method for manufacturing single-sized material composition |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2834818B1 (en) * | 2002-01-14 | 2006-09-15 | Atofina | MICROCOMPOSITE POWDER BASED ON GRAPHITE PLATES AND A FLUOROPOLYMER AND OBJECTS MADE WITH THE POWDER |
-
2018
- 2018-09-19 DE DE102018215904.1A patent/DE102018215904A1/en active Pending
-
2019
- 2019-08-22 CN CN201980061679.6A patent/CN112740448A/en active Pending
- 2019-08-22 WO PCT/EP2019/072479 patent/WO2020057893A1/en active Application Filing
Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH073484A (en) * | 1991-08-23 | 1995-01-06 | Tanaka Kikinzoku Kogyo Kk | Manufacture of gas diffusion electrode |
| US6465041B1 (en) * | 2001-12-19 | 2002-10-15 | 3M Innovative Properties Company | Method of making gas diffusion layers for electrochemical cells |
| JP2008171702A (en) * | 2007-01-12 | 2008-07-24 | Toyota Motor Corp | Manufacturing method of fuel cell assembly, manufacturing method of fuel cell, fuel cell assembly and fuel cell |
| JP2010015832A (en) * | 2008-07-03 | 2010-01-21 | Toyota Motor Corp | Gas diffusion layer for fuel cell, and membrane-electrode assembly and fuel cell using the same |
| CN102047478A (en) * | 2008-10-31 | 2011-05-04 | 松下电器产业株式会社 | Membrane electrode assembly and fuel cell |
| CN101608323A (en) * | 2009-07-02 | 2009-12-23 | 昆明理工大学 | The preparation method of zero-anode-potential hydrogen-diffusion anodes |
| US20170200954A1 (en) * | 2015-09-16 | 2017-07-13 | Uti Limited Partnership | Fuel cells constructed from self-supporting catalyst layers and/or self-supporting microporous layers |
| CN107819112A (en) * | 2016-09-13 | 2018-03-20 | 罗伯特·博世有限公司 | Method for manufacturing single-sized material composition |
Also Published As
| Publication number | Publication date |
|---|---|
| WO2020057893A1 (en) | 2020-03-26 |
| DE102018215904A1 (en) | 2020-03-19 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CA2136133C (en) | Improved manufacture of electrodes | |
| JP5436065B2 (en) | Gas diffusion layer for polymer electrolyte fuel cells | |
| US9899685B2 (en) | Method of making a proton exchange membrane using a gas diffusion electrode as a substrate | |
| EP1944819B1 (en) | Method for producing membrane electrode assembly for solid polymer fuel cell | |
| JP3555999B2 (en) | Method for producing polymer solid electrolyte / electrode assembly for polymer electrolyte fuel cell | |
| KR101931890B1 (en) | Membrane electrode assembly | |
| JP7486931B2 (en) | Method for manufacturing electrochemical reactor flow guides | |
| JP2008103164A (en) | Composite material of carbon and water-repellent material | |
| JP2001520445A (en) | Membrane electrode assembly | |
| JPH08329962A (en) | Polymer solid electrolyte film/electrode integrally molded body and manufacture thereof | |
| CN102104159A (en) | Novel gas diffusion layer used for fuel cell, preparation and application | |
| JPH11126615A (en) | Electrode for fuel cell and manufacture of electrode for fuel cell | |
| US20120141914A1 (en) | Gas Diffusion Layer Member For Solid Polymer Fuel Cells, and Solid Polymer Fuel Cell | |
| US20180323441A1 (en) | Membrane electrode gas diffusion layer assembly and manufacturing method thereof | |
| JP2001057218A (en) | Solid polymer type fuel cell and manufacture thereof | |
| DE102013205284A1 (en) | Making a membrane electrode assembly comprises applying a porous reinforcement layer to the wet ionomer layer | |
| JP2006339018A (en) | Gas diffusion layer for fuel cell and its manufacturing method | |
| US11283082B2 (en) | Gas diffusion electrode and production method therefor | |
| JP5410787B2 (en) | Gas diffusion layer for polymer electrolyte fuel cells | |
| KR20030081406A (en) | Gas diffusive electrode body, method of manufacturing the electrode body, and electrochemical device | |
| CN112689920A (en) | Method for producing a gas diffusion layer for a fuel cell | |
| JP7336761B2 (en) | Membrane electrode assembly and fuel cell | |
| US6579639B1 (en) | Polymer electrolyte fuel cell | |
| CN112740448A (en) | Method for producing a membrane electrode unit for a fuel cell | |
| JP5177467B2 (en) | SHEET-FORMING MATERIAL FOR FUEL CELL SEPARATOR, ITS MANUFACTURING METHOD, AND FUEL CELL SEPARATOR |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |