EP3362593A1 - Tissu aiguilleté de faible grammage, son procédé de fabrication et son utilisation dans une couche de diffusion pour une pile à combustible - Google Patents
Tissu aiguilleté de faible grammage, son procédé de fabrication et son utilisation dans une couche de diffusion pour une pile à combustibleInfo
- Publication number
- EP3362593A1 EP3362593A1 EP16793966.9A EP16793966A EP3362593A1 EP 3362593 A1 EP3362593 A1 EP 3362593A1 EP 16793966 A EP16793966 A EP 16793966A EP 3362593 A1 EP3362593 A1 EP 3362593A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- fabric
- diffusion layer
- range
- carbon
- weight
- 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.)
- Withdrawn
Links
Classifications
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/86—Inert electrodes with catalytic activity, e.g. for fuel cells
- H01M4/88—Processes of manufacture
- H01M4/8803—Supports for the deposition of the catalytic active composition
- H01M4/8807—Gas diffusion layers
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- D—TEXTILES; PAPER
- D03—WEAVING
- D03D—WOVEN FABRICS; METHODS OF WEAVING; LOOMS
- D03D9/00—Open-work fabrics
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B25/00—Layered products comprising a layer of natural or synthetic rubber
- B32B25/10—Layered products comprising a layer of natural or synthetic rubber next to a fibrous or filamentary layer
-
- D—TEXTILES; PAPER
- D03—WEAVING
- D03D—WOVEN FABRICS; METHODS OF WEAVING; LOOMS
- D03D13/00—Woven fabrics characterised by the special disposition of the warp or weft threads, e.g. with curved weft threads, with discontinuous warp threads, with diagonal warp or weft
- D03D13/008—Woven fabrics characterised by the special disposition of the warp or weft threads, e.g. with curved weft threads, with discontinuous warp threads, with diagonal warp or weft characterised by weave density or surface weight
-
- D—TEXTILES; PAPER
- D03—WEAVING
- D03D—WOVEN FABRICS; METHODS OF WEAVING; LOOMS
- D03D15/00—Woven fabrics characterised by the material, structure or properties of the fibres, filaments, yarns, threads or other warp or weft elements used
- D03D15/20—Woven fabrics characterised by the material, structure or properties of the fibres, filaments, yarns, threads or other warp or weft elements used characterised by the material of the fibres or filaments constituting the yarns or threads
- D03D15/242—Woven fabrics characterised by the material, structure or properties of the fibres, filaments, yarns, threads or other warp or weft elements used characterised by the material of the fibres or filaments constituting the yarns or threads inorganic, e.g. basalt
- D03D15/275—Carbon fibres
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/86—Inert electrodes with catalytic activity, e.g. for fuel cells
- H01M4/8605—Porous electrodes
-
- 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
-
- D—TEXTILES; PAPER
- D10—INDEXING SCHEME ASSOCIATED WITH SUBLASSES OF SECTION D, RELATING TO TEXTILES
- D10B—INDEXING SCHEME ASSOCIATED WITH SUBLASSES OF SECTION D, RELATING TO TEXTILES
- D10B2101/00—Inorganic fibres
- D10B2101/10—Inorganic fibres based on non-oxides other than metals
- D10B2101/12—Carbon; Pitch
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- 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
-
- 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
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
- Y02P70/50—Manufacturing or production processes characterised by the final manufactured product
Definitions
- the present invention relates to the field of materials used in electrochemical systems or devices, such as fuel cells.
- the invention relates to a fabric, in particular needled, having a low basis weight, its manufacturing process and its use as a support in a diffusion layer.
- a fuel cell type PEMFC Proton Exchange Membrane Fuel Cell
- PEMFC Proton Exchange Membrane Fuel Cell
- a battery comprises at least one electrochemical cell, but more generally a stack of a series of several electrochemical cells to meet the needs of applications, connected to one or more current collectors.
- Each electrochemical cell comprises a membrane-electrode assembly (AME) that provides electrochemical conversion.
- AME membrane-electrode assembly
- a membrane-electrode assembly is composed of:
- GDL diffusion diffusion layers
- the conductive membrane is based on one or more protonic or ionomeric polymers, generally based on a perfluorosulfonated polymer of Nafion® type. It separates the anode from the cathode and does not let electrons and gases pass. She drives the protons.
- the electrodes are formed of a catalyst (usually platinum), carbon and ionomer. They must allow the transport of protons to the membrane, the transport of electrons to the current collectors via diffusion layers and bipolar plates and the transport of reagents as well as reaction products, water and heat.
- Bipolar plates make it possible to ensure the distribution of gases, as well as the evacuation of excess water and reagents through millimeter channels, while conducting electricity. They are generally made of non-porous graphite or a carbon-polymer composite material.
- Diffusion layers have several functions in a stack. They must in particular allow the routing of the reagents (combustible and oxidant gas) and possibly water vapor, from the bipolar plate to the active layer; evacuation of liquid water and steam; conduction of the current produced at the level of the active layer to the bipolar plate; the evacuation of the heat produced at the level of the active layer; the mechanical reinforcement of the membrane / active layers assembly.
- a diffusion layer must have effective properties in terms of surface density, thickness, electrical conductivity, thermal conductivity, air permeability, hydrophobicity, chemical stability and stability. physical.
- the diffusion layers must be sufficiently rigid in order to serve as a mechanical reinforcement for the MEAs, because of the architecture of the channels of the bipolar plates. They must also be sufficiently porous to gases, in order to ensure the exchange of gas between the active layers and the polar plates and sufficiently porous with water, in order to ensure its evacuation towards the bipolar plates, without preventing humidification of the gases. active layers to promote proton transfer.
- the diffusion layers generally comprise a support, in the form of a carbon fiber reinforcement of the fabric, paper or felt type which is then rendered hydrophobic by a chemical treatment.
- a chemical treatment chemical is, for example, described in the application US 2014/025581.
- a microporous layer is also applied to these supports.
- the microporous layer consists of pores whose diameter is of the order of a micrometer. These pores are smaller than those of the support of the diffusion layer.
- the microporous layer is the interface between the diffusion layer and the active layer.
- the addition of a microporous layer to the support of a diffusion layer makes it possible to improve the performance of the cell, by having an action on the management of the water.
- Such a microporous layer is, for example, described in document US 2014/0205919.
- the design of a diffusion layer is therefore complex because its performance depends on the optimization between the properties of the support, the hydrophobic treatment, the microporous layer and the processability of all of these components.
- the processability of the support relates to the ability of a support to pass in different lines of coatings (thus its ability to be unrolled, to pass on different rolls and to be rewound) without deforming significantly.
- the processability of the support is estimated from its mechanical strength and its ability to be impregnated to the core, such impregnation being generally used during the hydrophobic treatment.
- EP 1445811 discloses a carbon fiber woven support for use as a diffusion layer.
- This support is formed of warp son and weft son in a carbon fiber precursor; the yarns have a linear density ranging from 0.005 to 0.028 g / m.
- the density of the threads is 20 thread / cm.
- the weight per unit area of this fabric given in this document ranges from 50 to 150 g / m 2 .
- This support is obtained by a pressurization step, in the direction of the thickness, of a carbon fiber precursor son fabric, followed by a carbonization stage of the fabric, in order to obtain a fiber fabric of carbon.
- the pressurization step reduces the thickness of the support.
- This fabric is slightly deformable in compression.
- the used wires for the manufacture of this woven support are very fine, so expensive to produce, and fragile. These yarns can break easily, which potentially impacts the speed of manufacture of the woven support and its processability.
- WO 2011/131737 discloses a support for a diffusion layer, the support being formed of a plurality of unidirectional layers of carbon son superimposed and interconnected by an entanglement of broken carbon son, obtained by needling.
- the unidirectional layers are superimposed on each other, alternating the orientation of each of the layers.
- the needling is carried out in a direction parallel to the thickness of the multiaxial sheet produced.
- the assembly obtained is difficult to process and it is, in most cases, necessary to carry out a post-treatment to consolidate the assembly for manipulation or transport.
- the agents present in the post-treatment may reduce the performance of the diffusion layer.
- the diffusion layers currently marketed are based on textile, paper-like, non-woven or woven made from carbon fibers. The best properties are today achieved with paper and non-woven media.
- paper and nonwoven type supports have several disadvantages.
- the carbon fibers are oriented in an unorganized manner. This can lead to non-optimal reproducibility of the characteristics of the broadcast medium made.
- the paper-type or non-woven supports are difficult to handle, especially when they have a basis weight less than or equal to 100 g / m 2 .
- additives such as binders or stabilizers, are added to these supports. However, these additives can pollute the diffusion layer and reduce its performance. A The depollution step is then often necessary to be able to use the diffusion layer, which increases the cost and the complexity of their manufacturing process.
- the invention proposes to respond to the problems mentioned above, by providing a new support for a diffusion layer that has good processability and good performance in terms of current density, as well as its manufacturing process.
- This objective is achieved thanks to a fabric composed of carbon threads, needled and having a density in the range of 40 g / m 2 to 100 g / m 2 .
- a first subject of the invention relates to a fabric comprising carbon threads, said fabric having a mass per unit area in the range from 40 g / m 2 to 100 g / m 2 , preferably in the range of 40 g / m 2 to 80 g / m 2 , in particular in the range from 60 g / m 2 to 80 g / m 2 , characterized in that it comprises staple fibers, said staple fibers extending from constituent yarns of the fabric from which they arise and extending not parallel to the direction of the wire from which they are derived.
- the fabric according to the invention simultaneously has a good compromise between surface mass, thickness, permeability, porosity, electrical conductivity, physical stability and chemical stability. It also presents the advantage of being easily processable without the addition of additives. It is therefore perfectly suited to serve as a support in a diffusion layer for fuel cells.
- Another object of the invention relates to the use of a fabric as defined in the context of the invention for the manufacture of a diffusion layer, in particular for a fuel cell.
- the subject of the invention is also a diffusion layer for a fuel cell, characterized in that it comprises at least one fabric according to the invention, said fabric comprising at least one hydrophobic coating.
- a diffusion layer may further comprise at least one microporous layer.
- Such a microporous layer will be deposited on at least a portion of the coating present on the surface of the fabric according to the invention.
- the invention also relates to a method for manufacturing a fabric according to the invention, characterized in that it comprises at least the following steps:
- the invention also relates to a fuel cell comprising at least one diffusion layer according to the invention.
- Figure 1A is a schematic representation of a cross section of a fabric that can be used in the context of the invention, before any needling step.
- Figure 1B is a schematic representation of a cross section of a fabric according to the invention, corresponding to the fabric of Figure 1A, after needling.
- Figure 1C is a magnification of a portion of Figure 1B showing a fi! of warp and a weft thread.
- Figure 2 is a schematic sectional representation of a GDL.
- Figure 3A is a schematic representation of the fixture used for the measurements of the resistivity in the plane of the fabric and Figures 3B and 3C show the measurement points.
- Figure 4 illustrates the measurement of stiffness and compressibility stress.
- Figure 5 illustrates the measurement of shear stress.
- FIG. 6 shows the polarization curves of AME comprising a diffusion layer according to the invention (GDL-2, GDL-3, GDL-4, GDL-5 and GDL-7) and a polarization curve of an AME. comprising a diffusion layer outside the invention (GDL-1).
- FIGS. 7A, 7B, 7C show the polarization curves of AME comprising a diffusion layer according to the invention (GDL-6) and an out-of-invention diffusion layer (GDL-1), for temperature and humidity packaging. different.
- FIG. 8 shows the polarization curves of AME comprising a diffusion layer according to the invention (GDL-5) and a diffusion layer according to the invention for which the needling conditions have been optimized (GDL-6).
- Figure 9 shows the polarization curves of AME comprising a diffusion layer according to the invention (GDL-10) or an diffusion layer outside the invention (GDL-1).
- Figure 10 shows the polarization curves of AME comprising a diffusion layer according to the invention (GDL-9) and an out-of-invention diffusion layer (GDL-8), corresponding to a non-needled fabric.
- FIG. 11 shows the polarization curves of AME comprising a diffusion layer according to the invention (GDL-6) and an out-of-invention diffusion layer (GDL-11) corresponding to a multiaxial needled sheet.
- the present invention relates to a fabric comprising carbon threads, said fabric having a basis weight in the range of 40 g / m 2 to 100 g / m 2 , preferably in the range of 40 g / m 2 to 80 g / m 2 , in particular in the range from 60 g / m 2 to 80 g / m 2 , and characterized in that it comprises staple fibers, said staple fibers extending from constituent yarns of the fabric of which they are exits and extending non parallel to the direction of the wire from which they are derived and / or in that the fabric is needled.
- fabric means a regular assembly of warp son and weft son by weaving, that is to say with intercrossing and interlacing.
- weight per unit area is meant the ratio of the mass of a piece of fabric to its surface.
- the weight per unit area may in particular be measured according to IS03374.
- the fabrics defined within the scope of the invention are preferably composed of at least 90% by weight, or even consist exclusively of carbon threads.
- the fabrics are not composed exclusively of carbon threads, not more than 10% by weight of the fabric may be composed of polymer-based sizing and / or other yarns making up said fabrics, which may especially be glass yarns. , polymer yarns or hybrid glass-polymer yarns.
- the warp yarns and weft yarns are preferably all carbon yarns.
- the warp yarns are identical carbon yarns and the weft yarns are identical carbon yarns or the warp yarns and the weft yarns are all identical.
- a carbon yarn consists of a set of filaments and generally has from 1,000 to 80,000 filaments (this is referred to as 1 to 80K yarn), preferably from 3,000 to 24,000 filaments.
- the filaments can freely move relative to each other. It's the same for carbon threads.
- a filament is characterized by a very long length, and can be called continuous fiber.
- the linear density of a yarn, in particular a yarn! of carbon belongs to the range of 0.03 to 4 g / m, and preferably in the range of 0.2 to 2 g / m.
- the number of warp or weft threads belongs, independently, to the range from 0.4 to 2 threads / cm.
- the fabrics according to the invention are characterized by the presence of staple fibers extending from at least a portion of the constituent yarns of the fabric.
- a discontinuous fiber corresponds to a filament still attached to the wire, but having been cut while remaining attached to the wire.
- a discontinuous fiber extends not parallel to the direction of the wire from which it originates. This is called disorientation of the discontinuous fiber with respect to the wire from which it originated and from which it extends.
- This disorientation corresponds to a change of orientation in a carbon thread of at least one filament because of its cutting and thus the creation of a discontinuous fiber, in particular outside the plane of the fabric and / or outside the weaving lines.
- the change of orientation of at least one cut filament corresponding to a discontinuous fiber in a carbon thread is effected outside the plane of the fabric, that is to say according to its thickness.
- extending not parallel to the direction of the wire is meant a fiber obtained by cutting a filament comprised in a yarn, which deviates from the general direction of said yarn, in particular which deviates from the yarn. longitudinal axis of said wire.
- a discontinuous fiber corresponds to a filament of which one end is free or cut.
- This cut end corresponds to a discontinuous fiber and somehow forms a branch or branch on the wire in which the filament is present, which is why it is said to extend from said wire.
- the staple fibers may be derived from warp threads and / or weft threads.
- Some of the staple fibers are on the surface of the fabric, creating some hairiness on the fabric, while some of the staple fibers are in the fabric thickness, as shown in Figure 1B and the zoom shown in Figure 1C.
- Fibers lying in the thickness of the fabric may extend parallel to the plane of the fabric or according to the thickness of the fabric, that is to say not parallel to the plane of the fabric. It is said that a fiber extends according to the thickness of the fabric, if it forms with the plane of the fabric any non-zero angle, which may be equal to 90 ° or correspond to any value between 0 and 90 °.
- the orientation of the staple fibers according to the plane of the tissue or the thickness of the tissue that is to say extending in a plane different from the plane of the tissue, can be observed by microscopic photographs.
- the staple fibers present on the surface extend, for their part, preferably predominantly out of the fabric or emargent from the surface of the fabric, thus imparting hairiness to the fabric.
- the staple fibers within the fabric and the disorientation of these fibers with respect to the yarns from which they are derived can be obtained by mechanical breakage, of certain filaments constituting the carbon threads, produced by penetration of at least one point element which can be a needle-like member, in particular of the beard needle type, or jet of a fluid such as air or water.
- This type of technique, whatever the point element used (organ or jet), is called needling.
- the penetration, then the withdrawal of the needle or the pressure of the fluid also makes it possible to disorient the cut filaments and to orient the staple fibers obtained in several directions.
- the needling makes it possible to penetrate at least a portion of the staple fibers obtained in the thickness of the fabric, so that the latter extend according to the thickness of the fabric.
- needleled fabric is meant a fabric having undergone a needling operation.
- the result of the needling is, in particular, that the fabric is composed of yarns, in particular carbon yarns, some of whose filaments are cut and form staple fibers extending from said cut filament non-parallel to the direction of the wire from which they come. At least a portion of these staple fibers are in the thickness of the fabric. Some of the staple fibers are on the surface of the fabric, creating some hairiness on the fabric, while some staple fibers are in the fabric thickness, as shown in Figure 1B.
- FIG. 1A A cross section of a needle-punching fabric is shown schematically in Figure 1A.
- This fabric comprises a crisscrossing and intertwining of warp yarns 1 and weft yarns 3.
- Warp yarns 1 and weft yarns 3 are composed of filaments 2 and 4 respectively.
- the thickness of the fabric is symbolized by the arrow 5 and the fabric extends along a plane P, the two faces S of the fabric (also called large face) being parallel to this plane, taking into account the constant thickness of the fabric .
- plane of the fabric is meant the mid-plane of the fabric extending parallel to these two large faces (as opposed to the other faces of the fabric depending on the thickness, they, called small faces, the thickness corresponding to the smallest dimension of the fabric).
- FIG. 1B A cross-section of a fabric after needling is shown schematically in Figure 1B.
- This fabric always comprises an intercrossing and an interlacing of the warp yarns 1 and the weft yarns 3.
- Fibers 6, which come from the filaments of the warp yarns and weft yarns, can be oriented in the yarn of the fabric or in its yarn. thickness.
- Figure 1C which is a zoom of the section of the fabric shown in Figure 1B, there are discontinuous fibers 6a which extend parallel to the plane of the fabric, staple fibers 6b which extend according to the thickness of the fabric, while remaining in the thickness of the fabric and staple fibers 6c which extend according to the thickness of the fabric, leaving the surface of the latter.
- the fabric of the invention is needled with an impact density belonging to the range of from 50 to 650 impacts / cm 2 / face, especially in a range of from 55 to 300 impacts / cm 2 / face, preferably , in a range from 60 to 140 impacts / cm 2 / face, the impacts can be made from only one side of the fabric or from both sides.
- carbon threads of 1 to 48K for example, 3K, 6K, 12K or 24K, and preferably from 3 to 24K, are used.
- the title of the carbon threads used in the fabrics is in a range from 100 to 3200 Tex, especially in a range from 200 to 1600 Tex.
- the fabric can be made with any type of carbon son, for example, High Strength (HR) yarns whose tensile modulus is between 220 and 241 GPa and whose tensile tensile strength is generally between 3000 and 5000 MPa, Intermediate Module (IM) wires whose tensile modulus is between 280 and 300 GPa and whose tensile tensile strength is generally between 3450 and 6200 MPa and High Module (HM) wires whose tensile modulus is between 301 and 650 GPa and whose tensile breaking strength is between 3450 and 5520 Pa (according to ASM Handbook, ISBN 0-87170-703-9, ASM International 2001).
- HR High Strength
- IM Intermediate Module
- HM High Module
- the constituent yarns of the fabric may be non-sized or sized, in most cases, in this case with a mass content of standard size that can represent at most 2% of their mass.
- the weave of the fabric according to the invention may be of the taffeta (also called canvas), twill, braided, satin or derived from these weave, preferably taffeta type.
- a taffeta weave gives better hold to the fabric and has a number of back and forth threads between the two large faces of the upper fabric compared to other armor.
- the fabric of the invention is a fabric consisting, at least in part, of carbon yarns having a basis weight in the range of 40 g / m 2 to 100 g / m 2 , preferably in the range from 40 g / m 2 to 80 g / m 2 , especially in the range of 60 g / m 2 to 80 g / m 2 .
- the tissue, preferably needle-punched, according to the invention has, in particular, an opening factor in a range from 0% to 18%, preferably in a range from 0% to 10%.
- the aperture factor can be defined as the ratio multiplied by 100 between the area not occupied by the material and the total area observed, the observation of which can be made from the top of the fabric with illumination from below. latest.
- the opening factor (OF) is expressed as a percentage. It can, for example, be measured according to the method described in the examples.
- the fabric, preferably needled, according to the invention has, in particular, a surface resistance measured in the plane of the fabric less than or equal to 7 ohms.
- surface resistance is meant the ability of the fabric to oppose the flow of electric current.
- the surface resistance is measured at room temperature (22 ° C) by the displacement of electrodes on a large surface of the fabric and averaging these measurements. The experimental conditions for carrying out this measurement are given in detail in the example section.
- the fabric, in particular needled, according to the invention has a resistance, measured in the plane transverse to the plane of the fabric and a stack of four superposed folds of the same fabric, less than or equal to 0.5 ohms.
- the fabric, in particular the needled fabric, according to the invention being very thin, it appeared more representative to measure the resistance in the transverse plane of the plane of the fabric (that is to say according to its thickness) on a stack of 4 plies of fabric. the same fabric.
- a pii is the basic entity forming the fabric. The experimental conditions for carrying out this measurement are given in detail in the example section.
- the fabrics according to the invention which have discontinuous fibers which extend both in the plane of the fabric and according to its thickness, have the advantage of having an electrical conductivity in its three dimensions. This electrical conductivity is therefore distributed in the direction of the length, the width and in the direction of the thickness of the fabric. This better distribution of the conductivity in these three dimensions makes it possible to improve the performance of the diffusion layer.
- the fabric, in particular needled fabric, according to the invention preferably has an average thickness measured according to the ISO5084 standard of less than or equal to 400 ⁇ , in particular less than or equal to 350 ⁇ m, preferably belonging to a range from 35 ⁇ m to 300 ⁇ m. pm.
- the fabric, in particular needled fabric, according to the invention preferably has an air permeability measured according to the standard EN IS09237 less than or equal to 5000 m 2 , preferably less than or equal to 3000 m 2 .
- the fabric, in particular needled fabric, according to the invention has a water permeability less than or equal to 9 ⁇ 10 12 m 2 for a fiber volume ratio of 10%; less than or equal to 9.10 "13 m 2 , for a fiber volume of 30%, less than or equal to 2.10 13 m 2 for a fiber volume of 50%.
- the fiber volume ratio (FFT) of a fabric is calculated from the measurement of the thickness of the fabric by knowing the fabric mass per unit area and the properties of the carbon threads used, from the following equation: (3 ⁇ 4) is surfac ⁇ ⁇ u ⁇ xio I '(I)
- T car bone is the density of the fabric in g / m 2 .
- the fabric in particular needled fabric, according to the invention preferably has a compressibility rigidity (P2) greater than or equal to 1200 N / mm, in particular greater than or equal to 1500 N / mm.
- P2 compressibility rigidity
- the compressive rigidity is measured according to the method described in the experimental part.
- the fabric in particular needled fabric, according to the invention, preferably has a compressibility force of less than or equal to 350 N, in particular less than or equal to 300 N, said compressibility stress being measured for a fiber volume ratio (FVT) equal to 47%.
- FVT fiber volume ratio
- the fabric, in particular needled fabric, according to the invention preferably has a maximum shear load, measured in tension at 45 °, greater than or equal to 8 N, in particular greater than or equal to 10 N.
- This maximum shear load is measured on a fabric whose warp threads and weft threads are oriented at 45 ° with respect to the direction of the applied force.
- This method is described in the experimental part
- the overall porosity value (Po) of the fabric, in particular needled fabric, according to the invention is obtained according to the following formula:
- Another subject of the invention relates to a process for manufacturing a fabric according to the invention by needling; the method comprising the following steps:
- the fabric will have the following characteristics, determined according to the techniques detailed in the application WO 2014/135806 to which reference may be made for more details:
- a mass per unit area greater than or equal to 40 g / m 2 and less than 100 g / m 2 and a standard deviation of thickness measured on a stack of three identical fabrics deposited one on the other and in the same direction which is less than or equal to 35 pm,
- a mass per unit area greater than or equal to 40 g / m 2 and less than 100 g / m 2 , a standard deviation of thickness measured on a stack of three identical fabrics deposited on top of each other and in the same direction which is less than or equal to 35 pm and an average opening factor of 0 to 1%, preferably with an opening factor variability of not more than 1 and / or the fabric being preferably constituted by yarns having a titer of 200 to 3500 Tex, and preferably of 200 to 1700 Tex, in particular of 200 to 1600 Tex.
- the fabric has an aperture factor, before the needling step, in the range of 0% to 5%, especially in the range of 0% to 1%.
- the spreading of the fabric subjected to needling will be less than that described in the application WO 2014/135806.
- the needling step is performed by penetration of at least one point element which may be a needle-like member or a jet of a fluid.
- the penetration is carried out from at least one large face of the fabric, preferably in a direction transverse to the plane of the tissue (that is to say transverse to its two large faces).
- the fluid can be air or water. Needling makes it possible to disorientate and cut some of the constituent filaments of the woven carbon threads, by making the said point element penetrate inside the fabric.
- the needling causes a breakage of certain filaments constituting yarns, as described previously in the section "Fabric according to the invention", thereby creating staple fibers, said staple fibers extending from the constituent yarns of the fabric from which they originated and extending non-parallel to the direction of the wire from which they are derived.
- the needling operation makes it possible to increase the level of porosity of the fabric, due to an increase in thickness in particular, its variations being more or less important depending on the needling parameters. Needling will, in some cases, tend to increase, more or less markedly, the tissue opening factor.
- the density of impacts or penetration is, in particular, in a range from 50 to 650 impacts / cm 2 , in particular in a range from 55 to 300 impacts / cm 2 , preferably from 60 to 140 impacts / cm 2 , per side.
- impact density is meant the number of penetrations made from a large face per cm 2 of this large face.
- the impact density may be identical for each large face of the fabric or different from one large face to the other.
- the needling step will be carried out homogeneously, in particular, over all of at least one large face of the fabric.
- the total impact density, whether the penetration is made from only one or both large faces is in particular comprised in a range of from 50 to 1300 impacts / cm 2 , in particular in a range from 55 to 600 impacts / cm 2 , preferably
- the penetration elements will be positioned, preferably, offset from one face to the other.
- the needling step can be performed from a large face of the fabric or from its two large faces.
- the large faces may be needled simultaneously or one after the other, that is to say sequentially.
- the organ is a beard needle.
- a beard is a protruding or recessed part of the needle which has the function of cutting and / or hanging some of the filaments to penetrate the thickness of the fabric. The use of a beard needle allows during penetration to cause filaments from the penetration surface, the shrinkage causing the penetration of filaments from the other side.
- the needling step is performed by penetrating a needle preferably comprising at least one barb.
- the needles are metallic, which can be of several sizes, which can have a specific profile, with different numbers of barbs, themselves of specific size and profile. The skilled person will be able to choose the needles according to the conditions of needling and according to the tissue to needling.
- the beard needles have a vertical profile and a horizontal profile.
- the vertical profile corresponds to the cutting plane in the longitudinal direction of the needle.
- the horizontal plane corresponds to the cutting plane in the radial direction of the needle.
- the useful part of the needle may have, for example, a triangular horizontal profile, that is to say formed by three edges, or a star profile, that is to say formed of a star at 4 branches (or edges) with angles between 30 ° and 90 °, preferably between 30 ° and 70 °, more preferably between 30 ° and 50 °.
- the useful part of the beard needles used has a triangular horizontal profile which makes it possible to favor, depending on the orientation of the needle, the disorientation created by the needling, on the warp threads or the weft threads.
- the vertical needle profile can be standard (straight) or conical, preferably straight
- the needle comprises at least one barb or a plurality of barbs, preferably 2, 3, 4, 5, 6, 7, 8, 9 barbs, or more, the barb (s) being disposed on a useful length included , especially in a range from 3 to 30 mm.
- the number of beards per stop may in particular be less than or equal to 3, preferably it may be 1.
- the overall width of the useful portion of a needle at a beard may be, especially less than or equal to 3 mm, preferably belongs to a range from 0.3 to 1 mm.
- a beard is defined by a height and a depth. Depth is the maximum distance between the body of the needle and the most prominent part of the beard.
- the depth of a beard belongs, for example, to a range from 0.05 to 2 mm, preferably to a range from 0.05 mm to 0.5 mm.
- the length of a beard on the body of the needle preferably belongs to the range of 0.1 to 2 mm.
- Beard needles are, for example, marketed by Groz Berckert KG. It is possible to choose, for example, KV barb needles, HL barbs or RF barbs, preferably KV barb needles or HL barbs.
- the penetration will preferably be carried out with at least one barb needle, starting from less a large face of the fabric, and a distance allowing the penetration of at least one beard, or even the penetration of all the barbs present on the needle.
- At least part of the penetrations of the needle or needles used, or all penetrations will be performed by orienting the vertical profile of the needle, so that at least one of the barbs present on the needle is oriented not parallel to the first of the son she will meet during its penetration.
- Another subject of the invention concerns a fuel cell diffusion layer comprising at least one fabric as defined in the context of the invention or capable of being obtained by the manufacturing method as defined in the context of the invention.
- said fabric comprising at least one hydrophobic coating.
- coating is meant at least one element which covers at least partially, preferably completely, at least one surface of the tissue, or both, and which preferably penetrates inside the tissue, preferably at heart. , that is to say up to the middle zone of the tissue, called the heart.
- hydrophobic coating is meant at least one coating that repels water. Such a coating comprises at least one hydrophobic agent.
- the hydrophobic coating allows the diffusion layer to evacuate the water by creating preferential zones for discharging the liquid water.
- the hydrophobic coating prevents agglomeration of water in the pores of the diffusion layer. It also prevents clogging of the passage of reactive gases between the membrane and the active layers.
- the hydrophobic coating is obtained from a liquid composition which will be deposited on the support. Before it is deposited, this liquid composition comprises at least one hydrophobic agent suspended in a solvent such as water, ethanol, propanol, ethylene glycol and their mixtures.
- a solvent such as water, ethanol, propanol, ethylene glycol and their mixtures.
- the hydrophobic agent may especially be chosen from tetrafluoroethylene (PEE or in English PolyTetraFluoroEthylene) and fluorinated ethylene propylene (FEP or Fluorinated Ethylene Propylene).
- PEE tetrafluoroethylene
- FEP fluorinated ethylene propylene
- the hydrophobic coating further comprises carbon nanofibers.
- carbon nanofibers are present in the liquid composition, preferably with at least one dispersant.
- the mixture of carbon nanofibers and hydrophobic agent makes it possible to increase the conductivity and rigidity of the fabric, thus to improve the performance of the diffusion layer.
- carbon nanofibers is meant a carbon fiber, the diameter of which in particular belongs to the range from 20 to 1000 nm, preferably from 100 to 500 nm and having a length notably in the range from from 1 to 100 ⁇ m, preferably in the range of from 50 to 100 ⁇ m.
- Particularly interesting carbon nanofibers are VGCF (Vapor Grown Carbon Fiber), and especially VGCF®-H sold by Rhodia (France).
- dispenser is meant any chemical agent which prevents the agglomeration of carbon particles, especially carbon nanofibers.
- the dispersant may be selected from nonionic or anionic surfactants such as triton X100, nafion or Brij.
- the support After deposition of the composition, the support is subjected to a heat treatment, as explained below, leading to the final hydrophobic coating, which can be described as dry.
- the hydrophobic coating comprises in particular from 10 to 100% by weight, preferably from 40 to 50% by weight of at least one hydrophobic agent relative to the total weight of the hydrophobic coating.
- the hydrophobic coating comprises in particular, or consists of, from 10 to 30% by weight, preferably from 20 to 25% by weight of at least one hydrophobic agent and from 70 to 90% by weight, preferably from 75 to 80% by weight of carbon nanofibers relative to the total weight of the hydrophobic coating.
- the hydrophobic coating deposited on the fabric represents 70 to 120%, especially 70 to 90%, by weight relative to the weight of the fabric before treatment. This quantity makes it possible to obtain a diffusion layer having good performance in terms of electrical conductivity.
- the diffusion layer of the invention may in particular comprise, in addition, at least one microporous layer.
- microporous layer is meant a layer whose pore diameter of said microporous layer is in particular in a range from 0.01 to 10 ⁇ m, preferably in a range from 0.1 to 1 ⁇ m.
- the pore diameter is measured by scanning electron microscopy.
- the pores of the microporous layer are smaller in size than those of the diffusion layer.
- the microporous layer serves as an interface between the diffusion layer and the active layer and improves the performance of the battery, having an action on the water management. This increase in performance is obtained by the different properties of the microporous layer, especially by the micrometer pores.
- the size of the pores makes it possible to obtain a better distribution of the gases on the whole surface of the cell.
- the decrease in pore size between those of the diffusion layer and those of the microporous layer allows an acceleration of the passage of gases and therefore a decrease in condensation.
- the microporous layer also participates in the electrical conductivity of the diffusion layer. Since the microporous layer is generally composed mainly of carbon black, it facilitates the transport of electrons from the active layer to the external network. Thanks to good compatibility with the active layer and the diffusion layer, the microporous layer improves the interface between the active layer and the diffusion layer and thus reduces the contact resistance between these two layers.
- the carrier tissue of the hydrophobic coating may be associated with a microporous layer, on one of its large faces or on its two large faces.
- association is meant that the microporous layer (s) is (are) integral with the fabric.
- the microporous layer is in particular deposited in the form of a liquid composition on the carrier fabric of the hydrophobic coating. It may comprise carbon black and especially at least one hydrophobic agent chosen in particular from tetrafluoroethylene and fluorinated ethylene propylene. Carbon black increases the conductivity of the diffusion layer by facilitating the transfer of electrons from the active layer to the diffusion layer.
- the hydrophobic agent in the microporous layer makes it possible to improve the management of the water in the stack. Indeed, it allows, on the one hand, to retain the water at the active layer and the membrane allowing a good hydration of these components, and secondly, to evacuate the water more quickly. found at the level of the pores of the diffusion layer.
- the microporous layer can in particular comprise, in addition, carbon nanofibers.
- the carbon nanoframes make it possible to avoid the cracking of the deposition of the microporous layer during the evaporation of the solvent present in the deposited liquid composition. They will consolidate the structure without altering its electrical conductivity.
- Carbon nanofibers are chosen in particular from VGCFs (Vapor Grown Carbon Fiber), and will notably be VGCF®-H sold by Rhodia (France).
- the microporous layer may comprise in particular, or even consist of, from 30 to 45% by weight, preferably from 35 to 40% by weight of carbon black, from 5 to 20% by weight, preferably from 8 to 15% by weight of at least one hydrophobic agent, and 35 to 65% by weight, preferably 40 to 60% by weight of carbon nanofibers, the percentages being expressed relative to the total weight of the microporous layer .
- these% correspond to the final support, ie after the heat treatment steps, which lead to the elimination of the other compounds present in the applied composition, to form the diffusion layer, as explained below.
- the amount of microporous layer deposited on the fabric having a hydrophobic coating is in particular between 1 and 3 mg / cm 2 , preferably between 2.3 and 2.7 mg / cm 2 .
- Another object of the invention is a method of manufacturing a diffusion layer comprising at least the following steps:
- the liquid composition for forming a hydrophobic coating is obtained in particular by mixing and putting at least one hydrophobic agent in suspension in a solvent. that water.
- the fabric may be constrained to a determined thickness, which is preferably in the range of 100 to 300 ⁇ m measured according to ISO5084.
- the liquid composition to form the hydrophobic coating, comprises other ingredients in addition to the hydrophobic agent, it is obtained in particular in the following manner: at least one dispersing agent and carbon nanofibers are added to the hydrophobic agent in the solvent, such as water.
- This liquid composition is homogenized using a homogenizer, which comprises an enclosure, so as to obtain a suspension.
- the homogenizer may be, for example, a dispermat.
- the shaft of the homogenizer rotates at a speed in particular between 1500 and 2500 rpm, with a residual pressure in the chamber belonging to the range of -700 to -950 mbar, preferably -900 mbar, relative to at atmospheric pressure.
- the liquid composition may be homogenized for a period of time in particular between 15 minutes and 25 minutes.
- This homogenization step makes it possible in particular to break the aggregates present and to eliminate the gases that could be trapped in the composition.
- a dispersed and fluid composition is obtained, the viscosity of which is in particular between 0.8 and 1.1 mPa.s. This viscosity makes it possible in particular to obtain a homogeneous hydrophobic coating on the fabric used as a support.
- the liquid composition for the hydrophobic coating may comprise in particular from 1 to 10% by weight, preferably from 2 to 4% by weight of at least one hydrophobic agent and from 90 to 99% by weight. preferably at least 96 to 98% by weight of solvent such as water; the percentages by weight being expressed relative to the total weight of the liquid composition.
- the liquid composition for the hydrophobic coating may comprise from 0.5 to 3% by weight, preferably from 1 to 1.5% by weight of at least one hydrophobic agent, from 0.01 to 1% by weight, preferably from 0.1 to 0.5% by weight of at least one dispersing agent, from 1 to 5% by weight, preferably from 2 to 3% by weight of carbon nanofibers and from 80 to 99% by weight, preferably 92 to 98% by weight of solvent such as water; the percentages by weight being expressed with respect to the total weight of the liquid composition and their sum being preferably equal to 100%.
- the liquid composition may then be deposited on the tissue as defined in the context of the invention or may be obtained by the method as defined in the context of the invention.
- the deposit is most often made on the two large faces of the fabric and also with impregnation to the heart.
- the deposit can be made according to various techniques well known to those skilled in the art, you! the impregnation at heart, or the impregnation by spray, a surface deposit by roller press or with an impregnator.
- the deposition of the liquid composition for the hydrophobic coating may be carried out by impregnation and consists in immersing in a bath of said liquid composition, the fabric of the invention, preferably needle-punched, for example, for a period of time between 10 and 300 seconds. The time of contact between the fabric and said liquid composition, as well as the viscosity of this liquid composition, make it possible to control the amount of liquid composition impregnated in the fabric.
- the heat treatment step can be carried out, for example, at a temperature in a range of from 200 ° C to 450 ° C, preferably in a range of 250 to 350 ° C, under air.
- This step allows the consolidation of the hydrophobic coating, in particular by sintering the hydrophobic agent, as well as the evaporation of the additives such as the solvent and the dispersant (if present).
- the diffusion layer may further comprise a microporous layer.
- the diffusion layer can be obtained according to the method comprising the following successive steps: - Have at least one liquid composition to form a microporous layer,
- the liquid composition which will form the microporous layer is generally deposited on a single large face of the support carrying the hydrophobic coating. It is this large face that will be positioned in the GDL on the electrode side.
- the heat treatment that ultimately leads to the sintering of the composition will be preceded by an intermediate step of drying the fabric on which the liquid composition has been deposited.
- the liquid composition for forming a microporous layer may comprise at least one hydrophobic agent, carbon black and at least one solvent, such as water, ethanol, propanol, ethylene glycol and mixtures thereof.
- the hydrophobic agent is especially selected from tetrafluoroethylene (PTFE or English PolyTetraFluoroEthylene) and fluorinated ethylene propylene (FEP or English Fluorinated Ethylene Propylene).
- PTFE tetrafluoroethylene
- FEP fluorinated ethylene propylene
- the characteristics of the hydrophobic agent are preferably the same as those mentioned for the hydrophobic agent of the liquid composition making it possible to obtain the hydrophobic coating.
- the solvent present in the composition for the constitution of the microporous layer will preferably be chosen from water, ethanol, propanol, ethylene glycol and their mixtures.
- the liquid composition may comprise from 2 to 4% by weight, preferably from 2.5 to 3.5% by weight of at least one hydrophobic agent, from 1 to 6% by weight, preferably from 3 to 4% by weight. weight of carbon black and 70 to 95% by weight, preferably 85 to 90% by weight of at least one solvent, such as water; the percentages being expressed in relation to the weight total of the liquid composition, and their sum is preferably equal to 100%.
- the liquid composition for forming a microporous layer may furthermore comprise, in particular, at least one viscosifying agent, at least one dispersing agent and at least one carbon nanofiber.
- the carbon nanofibers are, in particular, carbon fibers whose diameter notably belongs to the range from 20 to 1000 nm, preferably to the range from 100 to 500 nm and having a length belonging in particular to the range from 0, 0.1 to 10 ⁇ m, preferably in the range of 0.1 to 1 ⁇ m.
- Particularly interesting carbon nanofibers are VGCF (Vapor Grown Carbon Fiber), and especially VGCF®-H sold by Rhodia (France).
- the dispersant makes it possible in particular to improve the dispersion of all the constituents of the liquid composition by breaking the aggregates. A homogeneous liquid composition is then obtained.
- the dispersant is chosen, in particular, from nonionic or anionic surfactants such as the X100 triton, nafion, Brij ...
- the characteristics of the carbon nanofibers and of the dispersing agent are preferably the same as those mentioned for the nanofibres and the dispersing agent of the composition making it possible to obtain the hydrophobic coating.
- the viscosifying agent makes it possible, in particular, to thicken the liquid composition to be deposited and to make it viscous so as to deposit it on the fabric having a hydrophobic coating. It thus prevents the latter from entering said fabric during its deposit.
- the viscosifying agent is chosen in particular from methylcellulose, carboxymethylcellulose and hydroxypropylmethylcellulose.
- the liquid composition for forming the microporous layer comprises, in particular, from 2 to 4% by weight, preferably from 2.5 to 3.5% by weight of at least one hydrophobic agent, from 1 to 6% by weight, preferably from 3 to 4% by weight of carbon black, from 0.1 to 5% by weight, preferably from 0.5 to 1.5% by weight of at least one dispersant, from 0.5 to 3% by weight, preferably from 1 to 2% by weight of at least one viscosifying agent, from 2 to 8% by weight, preferably from 4 to 5% by weight of carbon nanofibers and from 80 to 99% by weight, preferably from 85 to 95% by weight of at least one solvent water, the percentages being expressed relative to the total weight of the solution and their sum being preferably equal to 100%.
- the deposition of the liquid composition on at least one large face of the fabric having a hydrophobic coating is carried out by techniques well known to those skilled in the art such as spray deposition, deposition by screen printing, deposition by coating.
- the deposition is performed by the coating method which consists of spreading the liquid composition on at least one large face of the fabric having a hydrophobic coating by the translational movement of a bar or doctor blade.
- the thickness of the threading of the coating bar or the height of the doctor blade is particularly used, thus making it possible to obtain the loadings of the liquid composition in order to obtain the layer microporous desired.
- the liquid composition After spreading the liquid composition on said fabric, it may be dried, for example, directly on the coating bar at a temperature ranging from 60 ° C to 100 ° C.
- the drying time may especially be in a range from 0.5 to 5 minutes.
- the drying may make it possible to solidify the microporous layer by evaporating the solvent.
- the amount of microporous layer deposited is in particular in a range from 1 to 3 mg / cm 2 .
- the fabric, preferably needled, having a hydrophobic coating and its microporous layer deposition can then undergo a heat treatment especially for 1:30 to 2:30 hours and especially at a temperature in a range from 200 ° C to 450 ° C, preferably 250 to 350 ° C, under air.
- This step allows the consolidation of the microporous layer (in particular by sintering of the hydrophobic agent) as well as the evaporation of all the additives (viscosifying agent, dispersant, etc.) to leave only the final constituents of the microporous layer (hydrophobic agent, carbon fibers and carbon black).
- Another object of the invention is a fuel cell comprising at least one diffusion layer, as defined in the context of the invention or capable of being obtained by the method as defined in the context of the invention.
- fuel cell is meant a converter of chemical energy into electrical energy. Unlike a battery that undergoes charge and discharge cycles, a fuel cell can operate continuously as long as it is fed with reagent gases.
- the fuel cell can be in particular a Solid Oxide Fuel Cell (SOFC), a Molten Carbonate Fuel Cell (MCFC), a Phosphoric Acid Fuel Cell (Phosphoric PAFC). Fuel Cell Acid), a Proton Exchange Membrane Fuel Cell (PEMFC), a Direct Methanol Fuel Cell (DMFC) or an Alkaline Fuel Cell (AFC for Aikaline) Fuel Cell).
- SOFC Solid Oxide Fuel Cell
- MCFC Molten Carbonate Fuel Cell
- Phosphoric PAFC Phosphoric Acid
- PEMFC Proton Exchange Membrane Fuel Cell
- DMFC Direct Methanol Fuel Cell
- AFC Alkaline Fuel Cell
- FIG. 2 represents a fuel cell 21 according to the invention, in particular a proton exchange membrane fuel cell, comprising in particular at least one electrochemical cell 22 and at least one power supply 23.
- the electrochemical cell 22 comprises at least one assembly 24 of a membrane of at least one electrode and generally of two electrodes (AME), at least one seal 102 and generally two seals 102 and 103, at least a bipolar plate 104 and in general, two bipolar plates 104 and 105, and at least one diffusion layer 106 as defined in the context of the invention or obtainable by the method as defined in the context of the invention and in general, two diffusion layers 106 and 107 as defined in the the scope of the invention or obtainable by the method as defined in the context of the invention.
- AME a membrane of at least one electrode and generally of two electrodes
- the membrane-electrode assembly (AME) 24 comprises at least one membrane 101 and at least one electrode 108, in general, two electrodes 108 and 109.
- the supports for the diffusion layer that have been tested are either a non-woven carbon fiber paper carrier carrying a hydrophobic treatment and a microporous layer, hereinafter called S-NT marketed under the reference Sigracet. 24 BC sold by the company FuelCellsEtc, either woven supports or a stack of unidirectional sheets. This support has a mass per unit area of 100 g / m 2 and a thickness of 250 ⁇ !
- the tissues 1 to 5 are spread out and are obtained according to the methods described in applications WO 2014/135805 and WO 2014/135806.
- Carbon threads are available for example from Hexcel Composites.
- a stack of 0 ° / 90 ° / 90 ° of 4 unidirectional layers of carbon son was also used as support for a diffusion layer.
- Each unidirectional sheet has a basis weight of 50 g / m 2 and an opening factor of 0% before gapping. This stack is subjected to gapping on each of its faces (recto-verso).
- the fabrics or the multiaxial sheet are placed on a "needling" machine No. 040938269 manufactured by the company Andritz Asseltn-Thibeau S.A.S (Elbeuf, France).
- the needles used to obtain the S-1 and S-8 fabrics are SINGER type needles type 15 * 18 * 32 3.5 BL, RB 30 A06 / 15.
- the needles used to obtain the fabrics S-1 to S-4, S-7 and S-8 have a KV type beard profile.
- the needles used to obtain the fabric S-5 and S-6 have a beard profile type HL.
- the needles used to obtain the multiaxial needled sheet have a typical beard profile (ie rectilinear, non-conical).
- the measuring means used for the measurement of the surface resistance in the plane of the fabric and for the measurement of the resistance in the plane transverse to the plane of the fabric are the following:
- the copper conductive electrodes 301 (2.5 cm wide and 8 cm long) are placed on the same face of the fabric 303 at a distance of 80 mm from each other, as illustrated. in Figure 3A.
- R S q Ua re is equal to R x (w / L), with R the resistance read, w the measured media width (80 mm), and L the distance between the closest electrodes (80 mm).
- the tissue sample is placed on a hard, flat surface.
- the first 2 copper plates are placed on the sample. If an oxidation layer is present on the plates, then it is removed beforehand with a sander, for example, with an orbital sander. The oxidation layer may affect the accuracy of the measurement.
- the caliber made above is then placed, placing the copper plates in the appropriate areas. The gauge is lightly pressed on the electrodes.
- the value of the surface resistance corresponds to the average of these 7 measured measurements. The results are shown in Table III.
- the fabric to be tested is cut into 40x40mm samples so that a stack of 4 folds can be made.
- the superposed folds are wedged between the copper plates, the electrodes are pressed on them by the application of a torque of 0.3 Nm on the clamping screws.
- the measurement of the transverse permeability of each fabric is carried out according to the method described in the patent application WO 2010/046609.
- the transverse permeability can be defined by the ability of a fluid to cross a fibrous material in the transverse direction and therefore outside the plane of the reinforcement. It is measured in m 2 .
- the values of Table III are measured with the apparatus and measurement technique described in the Thesis entitled "The problem of measuring the transverse permeability of fibrous preforms for the fabrication of composite structures", by Romain Nunez, supported by National School of Mines of Saint Etienne, the 16th October 2009, to which we can refer for more details.
- the variation of the TVF is obtained by successive variations of the thickness of the sample.
- the purpose of the tests is to measure the permeability of the tested material at a given fiber volume ratio (FVT).
- FVT fiber volume ratio
- the TVF is varied by successive decreases in the thickness of the sample.
- the thickness of the sample is decreased and the next measurement begins only once the pressure drop is stabilized.
- the measurement is carried out in particular with a control of the thickness of the sample during the test by using two co-cylindrical chambers making it possible to reduce the influence of "race-tracking" (passage of the fluid on the side or "on the side Of the material whose permeability is to be measured).
- the fluid used is water and the pressure is 1 bar +/- 0.01 bar.
- the results of transverse permeability are presented in Table III and correspond to the average of the measurements made.
- the means used for the measurement of compressibility are as follows:
- thermocouple and Kane- May KM340 display.
- the compressibility measurements are carried out at a temperature of
- the purpose of the test is to compress the sample with a speed of 0.2 mm / min using a press having a diameter of 40 mm up to a fiber volume ratio (FVT) of 47%, the thickness used for the measurement of this TVF being that deduced according to the displacement.
- FVT fiber volume ratio
- the measurement is repeated once per sample on three different samples of the same tissue per test.
- the charge M corresponding to this TVF of 47% is measured.
- This load corresponds to the effort level in compressibility and is expressed in newton (N).
- a line P2 is drawn which is the tangent at point M to the curve of the load as a function of displacement (see Figure 4).
- the slope of P2 corresponds to the measurement of the compressibility rigidity; it is expressed in N / mm.
- the opening factor (OF) was measured according to the following method:
- the device consists of a SONY brand camera (model SSC-DC58AP), equipped with a lOx lens, and a Waldmann brand light table, model W LP3 NR, 101381 230V 50HZ 2xl5W.
- the sample to be measured is placed on the light table, the camera is fixed on a bracket, and positioned at 29cm from the sample, then the sharpness is adjusted.
- the measurement width is determined according to the sample to be analyzed, using the ring (zoom), and a rule 10 cm for the open textile samples (OF> 2%), 1.17 cm for unopened samples (OF ⁇ 2%).
- the brightness is adjusted to obtain a value of OF corresponding to that given on the control plate.
- the Videomet contrast measuring software from Scion Image (Scion Corporation, USA) is used. After image capture, the image is processed in the following way: using a tool, a maximum area corresponding to the chosen calibration is defined, for example, for 10 cm - 70 holes, and comprising a number of integer patterns. We then select an elementary surface in the textile sense of the term, that is to say a surface that describes the geometry of the fabric by repetition.
- the percentage OF is defined by a hundred times the ratio of the white surface divided by the total area of the elementary pattern: 100 x (white surface / elementary surface).
- the adjustment of the luminosity is important because diffusion phenomena can modify the apparent size observed for the porosity and thus the OF. An intermediate brightness will be retained, so that no phenomenon of saturation or diffusion too important is visible.
- the means used for the shear measurement (45 ° traction) are as follows:
- a specimen of the fabric to be tested is fixed on the adapted jaw, then the assembly on the stem of the INSTRON (50N cell).
- the fabric to be tested is placed, so that the threads of the fabric are oriented at +/- 45 ° with respect to the tensioning axis.
- the pulling speed is 20 mm / min.
- the load to be applied is measured as a function of the displacement of the jaw in order to draw the curve presented in Figure 5.
- the Point M is the maximum load in shear (traction at 45 °).
- the line P2 corresponds to the tangent of the curve at the point of inflection.
- the line P2 corresponds to the steepest slope of the measurement curve.
- the slope of line P2 corresponds to the measurement of shear stiffness; it is expressed in N / mm.
- the global porosity measurement (Po) is obtained from the following formula:
- the TVF corresponds to the volume rate of fibers as defined in the description (see formula I).
- a first step consists in treating the needle-punched (or not) fabric with a liquid composition intended to form a hydrophobic coating, followed by a thermal treatment in air at 350 ° C.
- a second step is to treat the tissue having a hydrophobic coating with a liquid composition for forming a microporous layer, followed by heat treatment at 350 ° C for 2 hours.
- Table IV shows the different formulations of the liquid compositions (C H) used for the formation of the hydrophobic coating (RH) in the diffusion layers.
- the percentages are percentages by weight expressed relative to the total weight of the liquid composition.
- the liquid compositions CRH-1 and CRH-2 are obtained by mixing the products and homogenizing the suspension using a dispermat.
- the percentages are percentages by weight expressed relative to the total weight of the dry hydrophobic coating.
- the liquid composition used for the formation of this microporous layer had the following composition (CL-MPL):
- This liquid composition is obtained by mixing the products and homogenizing the suspension using a dispermat, as described above for the liquid composition for depositing the hydrophobic coating.
- the percentages are percentages by weight expressed relative to the total weight of the liquid composition.
- the percentages are percentages by weight expressed relative to the total weight of the microporous layer finally obtained, after heat treatment.
- the GDL-2 to GLD-11 diffusion layers are obtained according to the operating conditions below.
- Table VI shows for each diffusion layer, the needle-punched (or not) fabric serving as support, the hydrophobic coating and the microporous layer used.
- the supports S-1 to S-10 are treated so that they have a hydrophobic coating.
- the supports are immersed in a bath of the liquid composition CRH chosen using an impregnating machine. Then, the supports undergo a heat treatment at 350 ° C under air.
- the CL-MPL liquid composition is then deposited by a previously obtained support coating method having a hydrophobic coating. After spreading the composition on said support, it is dried directly on the coating bench at 80 ° C to allow to solidify the microporous layer. Then, a heat treatment at 350 ° C. in air is carried out. Finally, 2.5 mg / m 2 of microporous layer is obtained. Hydrophobic coating Microporous layer
- the GDL-1 to GDL-11 diffusion layers are then used in an electrode membrane assembly (AME).
- the GDL-1 to GDL-11 diffusion layers are assembled with three layers (membrane corresponding to the diffusion layer, anode and cathode) in a 25cm 2 single-cell.
- the electrodes are composed of catalyst and a nafion ionomer.
- This mono-cell is then packaged and evaluated on a test bench to precisely control the operating conditions:
- the performance of the membrane-electrode assembly is determined by a polarization curve.
- the polarization curve of a membrane-electrode assembly indicates the evolution of the voltage as a function of the current density passing through the mono-cell. It thus makes it possible to evaluate the electrochemical performances of this mono-cell.
- FIG. 6 shows the polarization curves of AME comprising a diffusion layer according to the invention (GDL-2, GDL-3, GDL-4, GDL-5 and GDL-7) and a polarization curve of an AME. comprising a diffusion layer outside the invention (GDL-1).
- the diffusion layers according to the invention are as efficient as the GDL-1 commercial diffusion layer.
- the GDL-4 diffusion layer has slightly better performance at the commercially available GDL-1 diffusion layer.
- FIGS. 7A, 7B, 7C show the polarization curves of AME comprising a diffusion layer according to the invention (GDL-6) and a polarization curve of an AME comprising an diffusion layer outside the invention (GDL-1). , for different temperature and humidity conditions.
- Figure 7A conditioning 80 ° C, 50% RH (car)
- Figure 7B conditioning 60 ° C f 100% RH
- Figure 7C conditioning 80 ° C, 20% RH).
- the diffusion layers according to the invention have similar electrochemical performance as the diffusion layer outside the invention, which corresponds to the best commercial reference available.
- FIG. 8 shows the polarization curves of AME comprising a diffusion layer according to the invention (GDL-5) and a diffusion layer according to the invention for which the needling conditions have been optimized (GDL-6). These curves show that it is possible to improve the electrochemical performance of a diffusion layer by adapting the needling conditions on the woven support used.
- FIG. 9 shows the polarization curves of AME comprising a diffusion layer (GDL-10) according to the invention, the composition of the hydrophobic coating varies with respect to GDL-6 and a polarization curve of an AME comprising a layer. broadcast outside the invention (GDL-1).
- Figure 10 shows the polarization curves of AME comprising a diffusion layer according to the invention (GDL-9) and an out-of-invention diffusion layer (GDL-8) which uses the same fabric, but not needled. it appears that the needling greatly improves performance.
- FIG. 11 shows the polarization curves of AME comprising a diffusion layer according to the invention (GDL-6) and an diffusion layer outside the invention (GDL-11, unidirectional needled layer).
- GDL-6 diffusion layer according to the invention
- GDL-11 diffusion layer outside the invention
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- Textile Engineering (AREA)
- Electrochemistry (AREA)
- General Chemical & Material Sciences (AREA)
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- Manufacturing & Machinery (AREA)
- Sustainable Energy (AREA)
- Life Sciences & Earth Sciences (AREA)
- Sustainable Development (AREA)
- Inorganic Chemistry (AREA)
- Nonwoven Fabrics (AREA)
- Inert Electrodes (AREA)
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- Chemical Or Physical Treatment Of Fibers (AREA)
- Treatments For Attaching Organic Compounds To Fibrous Goods (AREA)
- Woven Fabrics (AREA)
Abstract
Description
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Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
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FR1559856A FR3042511B1 (fr) | 2015-10-16 | 2015-10-16 | Tissu aiguillete de faible grammage, son procede de fabrication et son utilisation dans une couche de diffusion pour une pile a combustible |
PCT/FR2016/052667 WO2017064443A1 (fr) | 2015-10-16 | 2016-10-14 | Tissu aiguillete de faible grammage, son procede de fabrication et son utilisation dans une couche de diffusion pour une pile a combustible |
Publications (1)
Publication Number | Publication Date |
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EP3362593A1 true EP3362593A1 (fr) | 2018-08-22 |
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Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
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EP16793966.9A Withdrawn EP3362593A1 (fr) | 2015-10-16 | 2016-10-14 | Tissu aiguilleté de faible grammage, son procédé de fabrication et son utilisation dans une couche de diffusion pour une pile à combustible |
Country Status (6)
Country | Link |
---|---|
US (1) | US20180301713A1 (fr) |
EP (1) | EP3362593A1 (fr) |
JP (1) | JP6871931B2 (fr) |
CN (1) | CN108884606A (fr) |
FR (1) | FR3042511B1 (fr) |
WO (1) | WO2017064443A1 (fr) |
Families Citing this family (4)
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CN108018637A (zh) * | 2018-01-05 | 2018-05-11 | 山东神华山大能源环境有限公司 | 一种聚酯纤维织物及其在湿式电除尘器中的应用 |
CN109585858B (zh) * | 2018-10-08 | 2021-06-15 | 武汉船用电力推进装置研究所(中国船舶重工集团公司第七一二研究所) | 一种具有疏水性的燃料电池气体扩散层的制备方法 |
CN110485028A (zh) * | 2019-07-31 | 2019-11-22 | 王一玫 | 一种新型纺织结构复合材料及其制备工艺和应用 |
CN112941957A (zh) * | 2020-10-12 | 2021-06-11 | 郭金武 | 一种自动控制浸渍量的碳纸连续生产方法 |
Family Cites Families (19)
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US4790052A (en) * | 1983-12-28 | 1988-12-13 | Societe Europeenne De Propulsion | Process for manufacturing homogeneously needled three-dimensional structures of fibrous material |
GB8700805D0 (en) * | 1987-01-15 | 1987-02-18 | Dunlop Ltd | Carbon fibre materials |
US5952075A (en) * | 1997-09-08 | 1999-09-14 | Fiberite, Inc. | Needled near netshape carbon preforms having polar woven substrates and methods of producing same |
DK1305268T3 (da) * | 2000-07-26 | 2010-12-20 | Ballard Power Systems | Carbonmatrix-kompositsammensætninger og dertil relaterede fremgangsmåder |
JP2003045443A (ja) * | 2001-07-27 | 2003-02-14 | Toho Tenax Co Ltd | 高分子電解質型燃料電池電極材用炭素繊維不織布、及びその製造方法 |
JP2003197202A (ja) * | 2001-12-26 | 2003-07-11 | Hitachi Chem Co Ltd | 高分子固体電解質燃料電池用ガス拡散層材料及びその接合体 |
CN1443885A (zh) * | 2002-03-13 | 2003-09-24 | 三菱化学株式会社 | 导电碳纤维织造布和固体聚合物型燃料电池 |
JP4283010B2 (ja) * | 2002-03-13 | 2009-06-24 | 三菱化学株式会社 | 導電性炭素質繊維織布及びこれを用いた固体高分子型燃料電池 |
JP2004124267A (ja) * | 2002-09-30 | 2004-04-22 | Toray Ind Inc | 炭素繊維織物、ガス拡散体、膜−電極接合体および燃料電池 |
FR2858465A1 (fr) * | 2003-07-29 | 2005-02-04 | Commissariat Energie Atomique | Structures poreuses utilisables en tant que plaques bipolaires et procedes de preparation de telles structures poreuses |
WO2006075681A1 (fr) * | 2005-01-14 | 2006-07-20 | Matsushita Electric Industrial Co., Ltd. | Empilement pour former une pile a combustible et pile a combustible |
KR100761524B1 (ko) * | 2006-02-02 | 2007-10-04 | 주식회사 협진아이엔씨 | 연료전지용 기체확산층의 제조 방법 |
US8074330B2 (en) * | 2008-08-13 | 2011-12-13 | Goodrich Corporation | Method and system for enabling z fiber transfer in needled preform |
JP2010102909A (ja) * | 2008-10-23 | 2010-05-06 | Nissan Motor Co Ltd | 燃料電池 |
WO2011074327A1 (fr) * | 2009-12-18 | 2011-06-23 | 日産自動車株式会社 | Couche de diffusion gazeuse pour pile à combustible et ensemble électrode à membrane utilisant ladite couche de diffusion gazeuse pour pile à combustible |
FR2959064B1 (fr) * | 2010-04-20 | 2013-01-11 | Commissariat Energie Atomique | Couche de diffusion d'un dispositif electrochimique et procede de realisation d'une telle couche de diffusion |
CN102011284B (zh) * | 2010-12-09 | 2013-05-01 | 甘肃宏伟碳素新材料有限公司 | 全钒液流储能电池专用碳毡生产工艺 |
CN103640319A (zh) * | 2013-11-25 | 2014-03-19 | 宜兴市飞舟高新科技材料有限公司 | 一种碳纤维复合板预制体的制作方法 |
JP6547936B2 (ja) * | 2015-01-30 | 2019-07-24 | 株式会社不二越 | 燃料電池用炭素繊維織物の製造方法 |
-
2015
- 2015-10-16 FR FR1559856A patent/FR3042511B1/fr active Active
-
2016
- 2016-10-14 WO PCT/FR2016/052667 patent/WO2017064443A1/fr active Application Filing
- 2016-10-14 US US15/766,854 patent/US20180301713A1/en not_active Abandoned
- 2016-10-14 CN CN201680074699.3A patent/CN108884606A/zh active Pending
- 2016-10-14 EP EP16793966.9A patent/EP3362593A1/fr not_active Withdrawn
- 2016-10-14 JP JP2018538952A patent/JP6871931B2/ja active Active
Also Published As
Publication number | Publication date |
---|---|
JP2018538461A (ja) | 2018-12-27 |
US20180301713A1 (en) | 2018-10-18 |
WO2017064443A1 (fr) | 2017-04-20 |
FR3042511B1 (fr) | 2018-04-20 |
FR3042511A1 (fr) | 2017-04-21 |
JP6871931B2 (ja) | 2021-05-19 |
CN108884606A (zh) | 2018-11-23 |
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