JP3825019B2 - Method for forming a catalytic coating on a substrate - Google Patents

Description

The present invention relates generally to fuel cells, and more particularly to a method for forming a catalytic coating on a substrate.
This application is a continuation-in-part of US Patent Serial No. 10 / 201,828, filed July 24, 2002.

Prior art literature is provided as follows.
US Patent No. 5,272,017 (Swathirajan et al. 12/1993) US Patent No. 5,316,871 (Swathirajan et al. 05/1994) US Patent No. 5,741,557 (Corbin et al. 04/1998) US Patent No. 5,798,186 (Fletcher et al. 08/1998) US Patent No. 5,973,295 (Corbin et al. 10/1999) US Patent No. 6,060,190 (Campbell et al. 05/2000) US Patent No. 6,074,692 (Hulett 06/2000) US Patent No. 6,171,721 (Narayanan et al. 01/2001) US Patent No. 6,387,559 (Koripella et al. 05/2002) US Patent Application Publication Number US 2001/0041277 (Chang 11/2001) U.S. Patent Application Publication Number US 2002/0051902 (Suenaga et al. 05/2002) US Patent Application Publication Number US 2002/0098405 (Odgaard et al. 07/2002) US Patent Application Publication Number US 2002/0110721 (Hatano et al. 08/2002) US Patent Application Publication Number US 2002/0058172 (Datz et al. 05/2002) Micropen (TM) Model 1000 data sheet Micropen (TM) Model 500 data sheet

In accordance with the present invention, a method is provided for forming a catalyst coating on a substrate.
In one embodiment, a method for forming a catalyst coating on a substrate is provided. According to the method, a catalyst fluid is prepared, the catalyst fluid being in a pattern that forms a catalyst coating on the first side of the substrate, using a direct drawing device programmed to discharge the catalyst fluid onto the substrate. It is discharged onto the substrate by.

In another embodiment, a method is provided for forming a catalyst coating on a substrate. In accordance with the method, the catalyst fluid is patterned onto the substrate using a direct drawing machine programmed to eject the catalyst fluid onto the substrate in a pattern that forms a first coating on the first side of the substrate. It is the discharge. Noncatalytic fluid, to form a second coating on the first side of the substrate, in a pattern of the shadows of the first coating, is discharged to the first side of the substrate using the same direct writing equipment .

In yet another embodiment, a method is provided for preparing an electrode membrane for use in a membrane electrode assembly. According to this method, the catalyst fluid in a pattern to form a catalyst coating on the intermediate material, using a direct drawing apparatus that is programmed to discharge the catalyst fluid is discharged onto the intermediate material. The catalyst coating is then transferred from the intermediate material to the electrode film.

In yet another embodiment, a method is provided for preparing an electrode membrane for use in a membrane electrode assembly. According to this method, the catalyst fluid is discharged onto the electrode material by using a direct-write equipment.

In yet another embodiment, a method for preparing a diffusion medium for use in a fuel cell is provided. According to this method, the catalyst fluid is discharged to the diffusion media using a direct drawing apparatus.

  In yet another embodiment, a system for preparing a membrane electrode assembly is provided. The system includes first and second coating stations, first and second drying stations, a cutting station, and a transport device. The first coating station comprises a first substrate holding device and at least one coating head for applying a coating to the first side of the substrate. The second coating station comprises a second substrate holding device and at least one coating head for applying the coating to the second side of the substrate. The transfer device is configured to transfer a substrate between stations.

  The above and other features and advantages of the present invention will be more fully understood from the following description of the invention, taken together with the accompanying drawings. It is noted that the scope of the present invention is defined by the description thereof, and not by the specific discussion of features and advantages described in this description.

  The following detailed description is best understood when read in conjunction with the accompanying drawings. Here, similar components are indicated using similar reference numerals.

  Those skilled in the art will appreciate that the components in the drawings are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, some dimensions of components in the drawings are exaggerated relative to other components to help improve the understanding of embodiments of the invention.

  Referring to FIG. 1, a fuel cell system 2 for automotive applications is shown. However, it should be appreciated that other fuel cell system applications may benefit from the present invention in the area of residential systems, for example. As shown, the fuel cell 2 comprises a primary reactor 4, a water gas shift reactor 6, a preferential oxidation (PrOx) reactor 7, at least one heat exchanger 8, a tail gas combustor 9, a fuel cell. 10. A description of the operation of these components and the fuel cell system 2 will be given below. While one particular fuel cell system design has been described, it should be appreciated that the present invention is applicable to any fuel cell system design where a catalyst coating is utilized.

In the primary reactor 4, a hydrocarbon fuel such as gasoline or methane, air, and steam are mixed and heated. The heated mixture is supplied to the catalyst-formed substrate. At this time , when the mixture flows over the catalyst and reacts with the catalyst , the mixture is separated into hydrogen, carbon monoxide and other process gases to form a hydrogen-rich stream. This reaction occurs at a temperature in the range of about 700 ° C to about 800 ° C.

The hydrogen rich stream leaving the primary reactor 4 flows into the water gas shift reactor 6. Oxygen from the water is used to convert carbon monoxide to carbon dioxide, leaving additional hydrogen and improving system efficiency. The operating temperature of the shift reactor 6 ranges from about 250 ° C to about 450 ° C. The hydrogen rich stream leaving the shift reactor 6 flows into the preferential oxidation reactor 7. Here, the final clean-up of carbon monoxide occurs before the hydrogen-rich stream enters the fuel cell stack. Air is added to supply the oxygen needed to convert most of the remaining carbon monoxide to carbon dioxide, leaving behind additional hydrogen. The operating temperature in the preferential oxidation reactor 7 ranges from about 80 ° C to about 200 ° C. Three reactors extract hydrogen from the fuel to reduce or eliminate harmful exhaust gases.

  The three reactors are rapidly heated to their operating temperature before the fuel is introduced. The heat exchanger 8 is therefore used to regulate various temperatures through the fuel cell system 2. Typically, the heat exchanger 8 preheats the steam and air streams before entering the primary reactor 4. The heat consumed from the hydrogen-rich stream leaves the primary reactor 4.

  The hydrogen-rich stream is fed to the fuel cell 10 that makes up the fuel cell stack, and reacts with oxygen from a source, such as air, to produce electricity that can be used to power the load 11. A small amount of unused hydrogen leaving the fuel cell 10 is consumed in the exhaust gas combustor 9 operating at a temperature of about 300 ° C to about 800 ° C. Although a series of reactors has been described as a hydrogen source, it should be appreciated that any hydrogen source is applicable to the present invention.

  Referring to FIG. 2, a vehicle having a vehicle body 90 and a fuel cell system having a fuel cell processor 4 and a fuel cell stack 15 is shown. The description of the present invention embodied in a fuel cell stack and a fuel cell will be described later with reference to FIGS.

FIG. 3 represents a fuel cell stack 15 having a pair of membrane electrode assemblies (MEAs) 20 and 22 separated from each other by a conductive fluid distribution plate 30. Plate 30 functions as a bipolar plate having a plurality of fluid flow channels for distributing fuel and oxidizing gas to membrane electrode assemblies 20 and 22. A “fluid flow channel” is a path, region, area or any section of a plate used to transport fluid within, along, or through the portion within at least a portion of the plate. Means. Membrane electrode assemblies 20 and 22 and plate 30 are stacked together between clamp plates 40 and 42 and conductive fluid distribution plates 32 and 34. Plates 32 and 34, as opposed to both sides of the plates, distribute fuel and oxidizing gas to membrane electrode assemblies 20 and 22, respectively, so that only one side functions as an end plate containing channels 36 and 38. .

  Non-conductive gaskets 50, 52, 54 and 56 provide a seal and electrical insulation between several components of the fuel cell stack. The gas permeable diffusion media materials 60, 62, 64 and 66 pressurize against the electrode surfaces of the membrane electrode assemblies 20 and 22. Plates 32 and 34 are pressurized against diffusion media material 60 and 66, respectively, and plate 30 is pressurized against diffusion media material 62 at the anode surface of membrane electrode assembly 20 and at the cathode surface of membrane electrode assembly 22. Pressure is applied to the diffusion media material 64.

For example, an oxidizing fluid such as O ₂ is supplied from the storage tank 70 to the cathode side of the fuel cell stack via an appropriate supply pipe 86. The oxidizing fluid is supplied to the cathode side, and a reducing fluid such as H ₂ is supplied from the storage tank 72 to the anode side of the fuel cell via an appropriate supply pipe 88. The reducing fluid can be derived from a mixture of methane or gasoline, air and water according to a reforming process in the presence of a catalyst. Exhaust piping (not shown) is also provided for both the H ₂ and O ₂ / air sides of the membrane electrode assembly. Additional piping 80, 82 and 84 are provided for supplying liquid coolant to the plate 30, plates 30 and 34. Appropriate plumbing for exhausting coolant from the plates 30, 32 and 34 is also provided, but is not shown.

  Referring to FIG. 4, an exploded view of the membrane electrode assembly 20 is shown with an anode layer 102, a cathode layer 106, and an electrolyte 104 that separates the anode layer 102 and the cathode layer 106. The membrane electrode assembly 20 and the membrane electrode assembly 22 are the same. For simplicity, the present invention will be described with respect to membrane electrode assembly 20. It should be appreciated that the present invention can be applied to the membrane electrode assembly 22 and general membrane electrode assemblies.

  In general, anode layer 102 and cathode layer 106 are coatings formed in such a manner that once fuel cell 10 (FIG. 1) is assembled, they are in intimate contact with the electrolyte material. A method for forming a catalyst coating on a substrate is described below. The first step in the method is to provide a catalyst fluid. In general, the catalyst fluid is a solution of ionomer, noble metal catalyst, solvent and water. A solution of ionomer and noble metal catalyst is typically prepared on a support in a mixture of solvent and water. Different amounts can be used depending on the desired viscosity of the catalyst fluid and the desired ratio of ionomer to carbon. Generally, about 30 grams to about 250 grams of solvent is mixed with about 130 grams to about 200 grams of water, and about 5 grams to about 30 grams of ionomer and about 5 grams to about 20 grams of noble metal catalyst form a solution. To be mixed together. The support used for the ionomer and noble metal catalyst solution is typically carbon with a high surface area. The amount of carbon is generally from about 5 grams to about 20 grams. More particularly, the catalyst solution is formed from about 4% by weight noble metal, about 4% by weight ionomer, about 4% by weight carbon, about 28% by weight water, and about 60% by weight solvent.

  The noble metal catalyst can be selected from platinum, platinum alloys and combinations thereof. The solvent can be selected from isopropyl alcohol, ethanol, butanol, and combinations thereof. The catalyst fluid can be prepared to exhibit a viscosity of about 70 cp to about 2000 cp, and more particularly, a viscosity of about 300 cp. The catalyst fluid can be prepared to exhibit an ionomer to carbon ratio of about 0.8 to about 2.0. The amount of solids in the solution is about 8% to about 20% by weight, and more specifically about 12% by weight.

Once the catalyst fluid is prepared, it is discharged onto the substrate 110 using a direct drawing apparatus. “Direct writing ” means depositing the fluid directly on the surface of the substrate in a pattern defined by instrument movement, substrate movement, or both. In direct writing , the deposited fluid forms a relatively well defined deposition line or region with respect to the deposition surface or the overall dimensions of the deposited pattern. The relative motion between the fluid source and the deposition substrate serves to extend a well-defined deposition line or deposition region to form a more extensive deposition pattern.

FIG. 5 shows an embodiment of a direct drawing device according to the present invention. The direct drawing device 150 includes a design system 152, a lighting system controller 154, and a lighting system 160. The lighting system 160 further includes a fluid distribution system 168, a nozzle 166, a nozzle tip 167, and a substrate holding device 162. The design system 152 controls the lighting system 160 in such a manner that the lighting system controller 154 knows the pattern and allows the lighting system 160 to draw the pattern stored in the design system 152 on the substrate 110. , In electronic communication with the lighting system controller 154.

Referring to FIGS. 5 and 6, the lighting system controller 154 is in electronic communication with the fluid dispensing system 168 and the substrate holder 162. Thus, the lighting system controller 154 allows the fluid distribution system 168 to deliver catalyst fluid to the nozzles 166. Catalyst fluid is discharged to the substrate 110 through the nozzle tip 167. The catalyst fluid may be conveyed to the fluid distribution system 168 by any suitable means.

The lighting system controller 154 allows the substrate holding device 162 to be moved to various positions that form the pattern 170 stored in the design system. By moving the substrate holding device 162 in various positions, the substrate 110 is correctly positioned below the nozzle tip 167 while the catalyst fluid is ejected onto the substrate 110. In this embodiment, the nozzle 166 and the nozzle tip 167 do not move and remain stationary while discharging the catalyst fluid. Further, the pressure at the nozzle tip 167 is controlled so that direct surface contact with the substrate 110 does not occur. In another embodiment, the substrate holding device 162 remains stationary while the nozzle 166 and nozzle tip 167 move across the substrate 110 while discharging the catalyst fluid.

The design system 152 may be any computer aided design (CAD) interface. This allows pattern design via a graphics editor, digital tablet, or interface through a comprehensive photoplotter interface. As the catalyst fluid is discharged easily through the nozzle tip 167, since the catalyst allowing fluid to maintain the dissolved state, it is possible to heat the nozzle 166. The width and thickness of the line or lines 169 forming the pattern 170 depend on the nozzle tip diameter, the volumetric flow rate of fluid to the nozzle tip, and the drawing speed. The drawing speed may vary depending on the movement of the substrate 110 relative to the nozzle tip 167 or the movement of the nozzle tip 167 relative to the substrate. Thus, the line thickness can be determined by the following equation: That is, t = Q / (Vw), where Q = volume flow rate, w = line width, V = drawing speed, and t = line thickness. The viscosity of the fluid determines how close the line width is to the nozzle tip diameter. That is, when a fluid with a low viscosity flows, the line width becomes larger than the nozzle tip diameter. In addition, when a fluid with a high viscosity does not flow, the line width becomes substantially equal to the nozzle tip diameter.

The nozzle tip 167 may form at least one line having a width from about 0.052 mm (about 0.002 inch) to about 6.35 mm (about 0.25 inch). If more than one line is desired, a space of up to about 0.0005 inches can be formed between the lines. The line thickness can be up to about 0.010 inches per nozzle pass. The line may have a tolerance of about ± 0.000025 inch. The device draws at a speed of about 1.27 mm (about 0.05 inches) per second to about 127 mm (about 5.0 inches) per second. The instrument 150 operates with a minimum grid pitch of 0.0127 mm (0.0005 inch).

The pattern 170 formed on the substrate 110 can be selected from a rectangular helix, a straight line, a series of lines, or any suitable geometric pattern. An example of a pattern 170 having a line or series of lines 169 forming a rectangular helix is shown in FIG. The spacing between adjacent lines can be adjusted. If there is no spacing between adjacent lines, the pattern 170 will form a single continuous coating across the substrate 110. FIG. 8 shows a pattern 170 having a series of lines 169 formed by a direct drawing machine according to one embodiment of the present invention.

Typically, after the pattern is formed on the substrate 110, the substrate 110 is dried by a heat source having a temperature of about 70 ° C to about 100 ° C. Once the pattern is dried, it forms a coating on the substrate 110. The heat source is selected from an infrared heater, convection oven, heated jet, or any other suitable heating device for removing solvent from the catalyst fluid. The substrate 110 is heated for a time sufficient to evaporate almost all of the solvent in the coating, more specifically from about 2 to about 10 minutes.

Method of making a membrane electrode assembly may vary depending on the substrate on which the catalyst fluid is discharged. The substrate is generally selected from an intermediate material, a diffusion media material, or an electrolyte membrane material.
If the substrate is an intermediate material, the catalyst solution is deposited in a programmed pattern on the intermediate material by a direct writing machine. The coated substrate is typically dried in an oven at a temperature of about 70 ° C. to about 100 ° C. After the substrate is dried, a secondary ionomer solution can be applied to the substrate and dried. Application of the ionomer solution is typically performed by a spraying process. Coating formed on the intermediate material is typically transferred to the electrolyte membrane material using a heating press transfer device. In one embodiment of the invention, the non-reactive second fluid may be applied after the catalyst fluid is deposited or simultaneously with the catalyst fluid. The coating formed on the intermediate material is transferred to the electrolyte membrane material. The intermediate material is typically selected from polytetrafluoroethylene, ethylenetetrafluoroethylene, or variations thereof. Non-catalytic fluids are described below.

A second substrate that can be used in the present invention is a diffusion media material. If a diffusion media material is used , the catalyst fluid is prepared as described above and then the diffusion media material using any of the patterns described above, using a direct writing instrument as described above. Deposited on top. The coated diffusion media material undergoes a drying process. The diffusion media material can be any suitable diffusion media material used in fuel cells. In one embodiment of the present invention, the second fluid that is a non-catalytic fluid may be applied onto the diffusion media material after deposition of the catalytic fluid or simultaneously with the catalytic fluid.

  As an alternative, the substrate can be an electrolyte membrane material. For this reason, the catalyst fluid is deposited directly on the electrolyte membrane material. The coated electrolyte membrane material undergoes a drying process. The electrolyte membrane material may be, for example, a proton transfer membrane such as perfluorinated sulfonic acid or its modified form.

  In one embodiment of the present invention, the non-catalytic second fluid may be applied onto the electrolyte membrane material after deposition of the catalyst fluid or simultaneously with the catalyst fluid, so that on one side of the electrolyte membrane material. Forming a catalytic coating and a non-catalytic coating; Referring to FIG. 9, a membrane electrode assembly 180 having both a catalytic coating 182 and a non-catalytic coating 184 is shown. The non-catalytic fluid forms a non-catalytic coating 184 when dried. The non-catalytic fluid is deposited in such a way that it forms a shadow of the catalytic fluid. “Shadow” means that one fluid follows the contour of the other fluid so that one fluid is not deposited directly over the other. In use, non-catalytic fluid fills the space between the lines of catalytic fluid on the substrate 202.

Non-catalytic fluids are materials that exhibit high electrical conductivity, high thermal conductivity, and low porosity. The non-catalytic fluid can be a carbonaceous material, carbon black, graphite, or a combination thereof. The carbonaceous material may be composed of a polymer binding material such as polyimide, polyethylene terephthalate, and combinations thereof. The viscosity of the non-catalytic fluid can be adjusted to an appropriate one to easily fill the area between the catalyst coatings shown in FIG. In general, non-catalytic fluids exhibit a viscosity of about 300 cp to about 10,000 cp. The non-catalytic fluid can be discharged such that the non-catalytic fluid is thicker on the substrate than the catalytic fluid.

  Referring to FIG. 10, one embodiment of a membrane electrode assembly 180 having a catalytic coating 182 and a non-catalytic coating 184 is shown. The catalyst fluid can be deposited in a pattern that allows the lines of catalyst coating 182 to align with the channels in the flow field plate. This can be accomplished on both sides of the substrate 202 such that the catalyst fluid that forms the catalyst anode coating 182a is aligned with the channels 185 of the anode flow field plate. Thus, the non-catalytic coating 182a is between the spaces of the catalytic fluid or catalytic anode coating 182a and forms a non-catalytic coating 184 on the lands 186 of the anode flow field plate. Similarly, on the cathode side of the membrane electrode assembly 180, the catalyst fluid that forms the catalyst cathode coating 182b is aligned with the channels 187 of the cathode flow field plate. Thus, non-catalytic fluid is deposited between the spaces of the catalytic fluid or catalytic cathode coating 182b to form a non-catalytic coating 184 on the lands 186 of the cathode flow field plate. The catalyst anode coating 182a and the catalyst cathode coating 182b are shown to be narrower than the openings in the channels 185, 187, respectively. The catalyst anode coating 182a and the catalyst cathode coating 182b may be formed such that the coating is as wide or wider than the channels 185, 187. This concept is explained in more detail in US patent application serial number 10 / 201,828.

  When a non-catalytic fluid is used to form a non-catalytic coating 184 on the substrate 202 and the substrate is an electrolyte membrane material, the fuel cell does not use the diffusion media material in the fuel cell. Thus, the resulting fuel cell is identical to the fuel cell 10 shown in FIG. 3, but the diffusion media 60, 62, 64 and 66 will be absent.

Referring to FIG. 11, a membrane electrode assembly manufacturing system 200 according to an embodiment of the present invention is shown. The system has three main stations. A first coating station, a second coating station and a cutting station. The substrate 202 is disposed on the feed roller device 212. In the roller apparatus, the substrate 202 is pulled from station to station by rollers 216, 218, 224 and 226. At the first coating station, the substrate 202 is pulled across the first substrate holding device 214. Once the substrate 202 reaches the first substrate holding device 214 , the nozzle 210a discharges the catalyst fluid directly onto the first side 202a of the substrate 202 . Catalyst fluid, as described above, is typically discharged in the form of a pattern. Next, the substrate 202 is pulled to the first drying region 215. The first drying zone 215 may be a heated jet train, an infrared heater, a convection oven, or any other suitable device for removing most of the solvent from the catalyst fluid. The first drying zone 215 typically maintains a temperature between about 70 ° C. and about 100 ° C. In the first drying region 215, the catalyst fluid dries on the substrate 202 and forms a catalyst coating on the substrate 202. The catalyst coating may be either an anode coating or a cathode coating.

The substrate 202 is then pulled to the second coating station. At the second coating station, the substrate 202 is pulled over the second substrate holding device 228. The catalyst fluid is deposited on the second side 202b of the substrate 202. Catalyst fluid, in a manner to form a pattern as described above, may be discharged on the substrate 22. While being pulled through the first drying region 215, the substrate 202 is opposite to the first side 202a of the substrate 202 such that the nozzle 202a discharges catalytic fluid on the second side 202b of the substrate 202. Is rotated in a manner that allows it to face. After the catalytic fluid is placed on the second side 202 b of the substrate 202, the substrate 220 is pulled to the second drying region 222. The second drying zone 222 may be a heated jet train, an infrared heater, a convection oven, or any other suitable device for removing most of the solvent from the catalyst fluid. The second drying zone 222 typically maintains a temperature between about 70 ° C. and about 100 ° C. While in the second drying region 222, the catalyst fluid deposited on the second side 202 b of the substrate 202 forms a catalyst coating across the substrate 202. The catalyst coating may be either an anode coating or a cathode coating.

  The substrate 202 is pulled to a cutting station 230 where the substrate 202 is cut into separate components such that each component of the substrate 202 has both an anode coating and a cathode coating. The substrate 202 may be further cut in a manner that does not intervene in a pattern that may be formed on the substrate 202 by a fluid.

  As FIG. 11 shows, more than one nozzle 210a, 210b, 220a, and 220b can be used at each station to deposit more than one fluid on the substrate 202 at a time. Although only two nozzles are shown at each station, it should be appreciated that a nozzle row can be provided. When more than one fluid is deposited at a time, one fluid can be a shadow of the other fluid. Although a non-catalytic fluid is described above as a second fluid, it should be appreciated that the second fluid can be any desired fluid. For example, the second fluid may be a fluid containing a significant amount of noble metal that is deposited near the inlet and outlet of the membrane electrode assembly. The fluid has a lower amount of noble metal and can be deposited in the center of the membrane electrode assembly, thereby reducing some of the durability degradation and mass transfer losses.

The nozzles 210a, 210b, 220a, and 220b are typically attached directly to the drawing device as described above. Fluid typically, in one form of the above-described pattern and is discharged onto the substrate 202. The catalyst fluid is prepared as described above. The first and second substrate holding devices 214 and 228 may be vacuum tables or any other device for holding the substrate in place.

Referring now to FIGS. 12a and 12b, there are shown steps that are added to the method of applying more than one fluid to a substrate. Ultrasonic energy can be applied to assist in coating the substrate 202. When the catalyst fluid 240 and a non-catalytic fluid 242 is discharged from the nozzles 210a and 210b to the substrate 202 can be over these fluids placing an ultrasound probe 250. Ultrasonic probe 250 transmits sonic energy 251 through the air above contact line 241 of catalytic fluid 240 and non-catalytic fluid 242, as shown in FIG. 12a. In particular as referenced in FIG. 12b, when the catalyst fluid 240 and a non-catalytic fluid 242 is discharged from the nozzles 210a and 210 b, the ultrasonic probe 250 in order to transmit the sonic energy through the substrate 202 disposed below the substrate 202 be able to. Sonic energy 251 is transmitted at the contact line 241 of the catalytic fluid 240 and the non-catalytic fluid 242.

Sonic energy 251 is continuously applied to contact line 241 such that the surface tension at the liquid-liquid interface continuously decreases at the location of application of sonic energy, thereby providing better fluid flow. And enables a smooth interface between the fluids 240 and 242. Although FIGS. 12a and 12b are shown using nozzles 240 and 242 operating at the first coating station, FIGS. 12a and 12b also show nozzles 220a and 220b operating at the second coating station. Should be acknowledged. Sonic energy 251 can be used in any suitable method system for making a membrane electrode assembly that ejects two fluids, including both catalytic and non-catalytic fluids, onto a substrate. Although this process has been described using sonic energy from an ultrasound probe, any device or energy that can relieve surface tension at the liquid-liquid interface can be used.

  Although the present invention has been described with reference to several preferred embodiments, it should be understood that numerous modifications can be made within the spirit and scope of the inventive concept described above. Accordingly, the present invention is not limited to the disclosed embodiments, but is intended to have the full scope possible with the language of the claims.

FIG. 1 is a schematic diagram of a fuel cell system. FIG. 2 is a schematic view of a vehicle including a fuel cell system. FIG. 3 is a schematic diagram of a fuel cell stack using two fuel cells. FIG. 4 is an exploded view of the membrane electrode assembly. FIG. 5 is a block diagram of a direct drawing apparatus according to an embodiment of the present invention. FIG. 6 is a diagram of a nozzle and a nozzle tip of a direct drawing apparatus for forming a pattern on a substrate according to an embodiment of the present invention. FIG. 7 is a diagram of a pattern according to an embodiment of the present invention. FIG. 8 is a diagram of a pattern according to an embodiment of the present invention. FIG. 9 is a diagram of a membrane electrode assembly according to one embodiment of the present invention. FIG. 10 is a diagram of one side of a membrane electrode assembly having first and second coatings, according to one embodiment of the present invention. FIG. 11 is a diagram of a membrane electrode assembly according to one embodiment of the present invention. FIG. 12a is a diagram of an ultrasound probe applied from above onto a substrate. FIG. 12b is a diagram of an ultrasonic probe applied from below onto a substrate.

Claims (3)

A method of manufacturing an article incorporating a fuel cell, comprising:
Prepare a fuel supply manifold,
Prepare an oxidizer supply manifold,
Preparing each membrane electrode assembly, including each step;
The step of preparing the membrane electrode assembly includes:
Preparing a catalyst fluid; and
Discharging the catalyst fluid onto the substrate in a predetermined pattern using a direct drawing device programmed to discharge the catalyst fluid onto the substrate to form a catalyst coating on the substrate; The predetermined pattern of the catalyst fluid is formed in a plane parallel to the substrate through movement of the direct drawing device; and
Transferring the catalyst coating from the substrate to a first side of an electrolyte membrane , wherein the catalyst coating is configured to align with a flow field channel of the fuel cell ;
Discharging the catalyst fluid onto the substrate in a predetermined pattern using a direct drawing device programmed to discharge the catalyst fluid onto the substrate to form a catalyst coating on the substrate; The predetermined pattern of the catalyst fluid is formed in a plane parallel to the substrate through movement of the direct drawing device; and
Transferring the catalyst coating from the substrate to a second side of an electrolyte membrane, the catalyst coating being configured to align with a flow field channel of the fuel cell ;
The membrane electrode assembly includes the fuel supply manifold, and a step of placing between the oxidant supply manifolds, methods. The method of claim 1 , wherein the article comprises a vehicle that is at least partially powered by the fuel cell. The method of claim 1 , wherein the article includes a power source that is at least partially powered by the fuel cell.

Images