JP3828455B2 - Manufacturing method of fuel cell - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
  The present invention provides a fuel cell that generates electricity by placing an ion exchange membrane between a positive electrode and a negative electrode, bringing hydrogen into contact with the negative electrode catalyst and oxygen in contact with the positive electrode catalyst.PondIt relates to a manufacturing method.
[0002]
[Prior art]
  FIG. 7 is an explanatory diagram for explaining a conventional fuel cell. In the fuel cell 100, an ion exchange membrane 103 is disposed between a negative electrode layer (hydrogen electrode) 101 and a positive electrode layer (oxygen electrode) 102, and hydrogen molecules (H₂) Are brought into contact with each other, and oxygen molecules (O₂) To contact the electron e⁻Is caused to flow as shown by an arrow to generate a current. When generating an electric current, hydrogen molecules (H₂) And oxygen molecules (O₂) And produced water (H₂O) is obtained.
  The fuel cell electrode having the negative electrode layer 101, the positive electrode layer 102, and the ion exchange membrane 103 of the fuel cell 10 as main components will be described in detail with reference to the following drawings.
[0003]
  FIG. 8 is an explanatory view showing a fuel cell electrode constituting a conventional fuel cell.
  The fuel cell electrode includes a binder layer 106 and a binder layer 107 inside the pair of diffusion layers 104 and 105, respectively, and a negative electrode layer 101 and a positive electrode layer 102 inside the binder layer 106 and the binder layer 107, respectively. An ion exchange membrane 103 is provided between the negative electrode layer 101 and the positive electrode layer 102.
[0004]
  When manufacturing the fuel cell electrode, first, a solution for the binder layer 106 is applied to the diffusion layer 104, and a solution for the binder layer 107 is applied to the diffusion layer 105. Binder layers 106 and 107 are solidified by firing.
[0005]
  Next, the negative electrode layer 101 solution is applied to the solidified binder layer 106, the positive electrode layer 102 solution is applied to the solidified binder layer 107, and the applied negative / positive electrode layers 101, 102 are dried to make negative The positive electrode layers 101 and 102 are solidified.
  Next, a sheet-like ion exchange membrane 103 is placed on the solidified negative electrode layer 101, and then a diffusion layer 105 on which the positive electrode layer 102 is solidified is placed on the ion exchange membrane 103 to form a seven-layer multilayer structure.
  Next, this multilayer structure is heat-pressed as shown by an arrow to form a fuel cell electrode.
[0006]
[Problems to be solved by the invention]
  As described above, the fuel cell electrode uses a sheet as the ion exchange membrane 103, and in addition, thermocompression bonding with the binder layer 106, the negative electrode layer 101, the positive electrode layer 102, and the binder layer 107 solidified. Therefore, there is a possibility that a poor adhesion portion may occur at the boundary between the layers.
  If poor adhesion occurs in each layer of the fuel cell electrode, it will be difficult to generate current efficiently, and these fuel cell electrodes will be discarded or repaired at the stage of inspection of the production line. Is an obstacle to increasing productivity.
[0007]
  Further, since the sheet is used as the ion exchange membrane 103 of the fuel cell electrode, when the fuel cell electrode is thermocompression bonded, the ion exchange membrane 103 is pressurized in a heated state. There is a possibility that the performance is lowered. This increases the number of parts that are subject to disposal or repair at the inspection stage, which hinders productivity.
[0008]
  In addition, since a sheet is used as the ion exchange membrane 103, the ion exchange membrane 103 needs to be thickened to some extent in consideration of the handling properties (handleability) of the ion exchange membrane 103. For this reason, it is difficult to make the fuel cell electrode thin, which hinders downsizing of the fuel cell electrode.
[0009]
  Therefore, an object of the present invention is to prevent the occurrence of a poor adhesion portion at the boundary of each layer, to further prevent the performance of the ion exchange membrane from being reduced, and to reduce the thickness of the ion exchange membrane. Fuel powerPondIt is to provide a manufacturing method.
[0010]
[Means for Solving the Problems]
  The inventors of the present invention have poor adhesion between the respective layers. After the previous coating has solidified, the following solution is applied, and this solution does not soak into the previous coating. It was determined that the cause of the poor adhesion was the cause.
  Then, when the next solution was stacked before the previous coating film was dried, it was found that the solution soaked into the previous coating film and the adhesion was remarkably increased.
  Similarly, when the solution was applied to the sheet-like ion exchange membrane, it was found that the solution was not soaked into the sheet-like ion exchange membrane, resulting in the occurrence of poor adhesion.
[0011]
  Accordingly, the present invention provides a solution for either one of the positive and negative electrode layers constituting the fuel cell on the sheet-like diffusion layer.A solution in which a catalyst having platinum or a platinum-ruthenium alloy supported on a carbon surface is mixed,A step of forming one electrode layer by coating, a step of forming an ion exchange membrane by applying a solution for an ion exchange membrane on the electrode layer while one electrode layer is undried, and an ion exchange While the membrane is undried, a solution for either the positive or negative electrode layer on this ion exchange membraneA solution in which a platinum-ruthenium alloy or a catalyst having platinum supported thereon is mixed on the surface of carbon,The step of coating to form the other electrode layer, the other electrode layer, the ion exchange membraneAndAnd said one electrode layerDryA fuel cell comprising a solidification step for drying and solidifyingPondProduction methodThe electrode layer solution uses a solvent having a higher vaporization temperature than the solvent used for the ion exchange membrane solution, and the drying in the solidification step is performed by electromagnetic wave heating. And
[0012]
  If a solution is employed for the ion exchange membrane and the electrode solution and the ion exchange membrane solution are applied in an undried state, mixing occurs at the boundary.
  Thereby, it is possible to prevent a poor adhesion portion from occurring at the boundary between each layer of the pair of electrodes and the ion exchange membrane, so that the reaction efficiency in the ion exchange membrane can be kept good.
[0013]
  Here, when a sheet is used for the ion exchange membrane, it is necessary to make the ion exchange membrane thick to some extent in order to keep the handleability of the sheet ion exchange membrane suitably. For this reason, it is difficult to make the electrode structure thin, which hinders downsizing of the electrode structure.
[0014]
  Accordingly, in claim 1, the ion exchange membrane is used as a solution, and the ion exchange membrane can be handled (handled) in a solution state. By using the ion exchange membrane as a solution, it is not necessary to regulate the thickness of the ion exchange membrane during handling. For this reason, the ion exchange membrane can be made thin, and the electrode structure can be made thin and downsized.
[0015]
  By the way, when generating a current using a fuel cell, hydrogen molecules (H₂) And oxygen molecules (O₂) Reacts with the generated water (H₂O). This generated water passes through the positive electrode side diffusion layer (carbon paper) and is discharged to the outside of the fuel cell.
  However, when an ion exchange membrane solution is applied onto an undried electrode layer, the ion exchange membrane solution may permeate into the electrode layer, and the permeated solution may block the gaps in the electrode layer.
  If the gap of the electrode layer is blocked with the solution for the ion exchange membrane, there is a concern that the generated water generated by the power generation cannot be efficiently discharged from the positive electrode side diffusion layer to the outside of the fuel cell.
[0016]
  If the generated water cannot be efficiently discharged, it is difficult to suitably supply the reactive gas such as hydrogen or oxygen, so that the concentration overvoltage becomes high and it becomes difficult to maintain the power generation performance of the fuel cell.
  The “concentration overvoltage” refers to a voltage drop that occurs when the rate of replenishment and removal of reactants and reaction products at the electrode is slow and the electrode reaction is disturbed. That is, when the concentration overvoltage becomes high, the amount of voltage drop increases.
[0017]
  Therefore, in claim 1, the drying of one electrode layer, the ion exchange membrane and the other electrode layer is performed using electromagnetic heating. By drying by electromagnetic wave heating, the inside of the ion exchange membrane can be efficiently heated and dried.
  Thus, by drying one electrode layer, the ion exchange membrane and the other electrode layer by electromagnetic heating, the ion exchange membrane can be quickly dried from the surface to the inside.
  Thereby, it can suppress that the solution of an ion exchange membrane osmose | permeates one electrode layer or the other electrode layer.
[0018]
  By suppressing the solution for the ion exchange membrane from penetrating into the electrode layer, it is possible to prevent the gap of the electrode layer from being blocked with the solution for the ion exchange membrane. Therefore, the generated water generated by power generation can be suitably discharged from the gap of the diffusion layer by guiding from the gap of the electrode layer to the diffusion layer.
[0019]
  Moreover,By using a solvent having a higher vaporization temperature than the solvent used for the ion exchange membrane solution as the electrode solution, the ion exchange membrane can be reliably dried in preference to the electrode layer. Therefore, it can suppress more efficiently that the solution for ion exchange membranes osmose | permeates an electrode layer.
  The electrode layer solution is characterized in that ethylene glycol or N · methyl pyrrolidone is used as a solvent.
[0020]
DETAILED DESCRIPTION OF THE INVENTION
  Embodiments of the present invention will be described below with reference to the accompanying drawings.
  FIG. 1 is an exploded perspective view showing a fuel cell having a fuel cell electrode according to the present invention.
  The fuel cell unit 10 is composed of a plurality (two) of fuel cells 11 and 11. In the fuel cell 11, the negative electrode side flow path substrate 31 is disposed outside the sheet-like negative electrode side diffusion layer 13 constituting the fuel cell electrode 12, and the sheet-like positive electrode side diffusion layer 14 constituting the fuel cell electrode 12. The positive-side flow path substrate 34 is disposed outside the surface.
[0021]
  By stacking the negative electrode side flow path substrate 31 on the negative electrode side diffusion layer 13, the flow path groove 31 a of the negative electrode side flow path substrate 31 is covered with the negative electrode side diffusion layer 13, thereby forming the hydrogen gas flow path 32. In addition, by stacking the positive electrode side flow path substrate 34 on the positive electrode side diffusion layer 14, the flow path groove 34 a of the positive electrode side flow path substrate 34 is covered with the positive electrode side diffusion layer 14, thereby forming the oxygen gas flow path 35. .
[0022]
  The fuel cell electrode 12 includes a negative electrode layer 17 as one electrode layer and a positive electrode layer 18 as the other electrode layer inside a negative electrode side diffusion layer 13 and a positive electrode side diffusion layer 14 via a binder, respectively. An ion exchange membrane 19 is provided between the layer 17 and the positive electrode layer 18.
  Thus, the fuel cell unit 10 is configured by providing a plurality (only two are shown in FIG. 1) of the configured fuel cells 11 via the separators 36.
  The fuel cell electrode 12 will be described in detail with reference to FIG.
[0023]
  According to the fuel cell unit 10, by supplying hydrogen gas to the hydrogen gas flow path 32, hydrogen molecules (H₂) And oxygen gas is supplied to the oxygen gas flow path 35, whereby oxygen molecules (O₂). As a result, electrons (e⁻) As shown by an arrow to generate a current.
  When generating an electric current, hydrogen molecules (H₂) And oxygen molecules (O₂) And produced water (H₂O) occurs.
[0024]
  FIG. 2 is an explanatory view showing a fuel cell electrode according to the present invention.
  The fuel cell electrode 12 includes a negative electrode layer 17 and a positive electrode layer 18 inside the negative electrode side diffusion layer 13 and the positive electrode side diffusion layer 14, respectively, and an ion exchange membrane 19 between the negative electrode layer 17 and the positive electrode layer 18.
  The negative electrode side diffusion layer 13 is a sheet material (sheet) composed of the carbon paper 13a on the negative electrode side and the binder layer 15a on the negative electrode side.
  Further, the positive electrode side diffusion layer 14 is a sheet material (sheet) composed of the positive electrode side carbon paper 14a and the positive electrode side binder layer 16a.
[0025]
  The binder constituting the negative electrode side binder layer 15a is a carbon fluororesin. The binder constituting the positive electrode side binder layer 16a is a carbon polymer having water repellency, and the carbon polymer corresponds to a skeleton of polytetrafluoroethylene introduced with sulfonic acid.
[0026]
  The negative electrode layer 17 is solidified by mixing the catalyst 21 in a negative electrode solution and drying the solution after application. The catalyst 21 of the negative electrode layer 17 is one in which (platinum-ruthenium alloy) 23 is supported as a catalyst on the surface of carbon 22, and hydrogen molecules (H₂) Is adsorbed.
[0027]
  The positive electrode layer 18 is solidified by mixing the catalyst 24 in a positive electrode solution and drying the solution after application. The catalyst 24 of the positive electrode layer 18 is obtained by carrying platinum 26 as a catalyst on the surface of carbon 25, and oxygen molecules (O₂) Is adsorbed.
[0028]
  The ion exchange membrane 19 is applied in the form of a solution between the negative electrode layer 17 and the positive electrode layer 18 and then dried together with the negative electrode layer 17 and the positive electrode layer 18 so as to be solidified integrally with the negative electrode layer 17 and the positive electrode layer 18. It is.
[0029]
  Next, the manufacturing method of the electrode 12 for fuel cells is demonstrated based on FIGS.
  FIGS. 3A to 3C are first process explanatory views showing a method of manufacturing a fuel cell electrode according to the present invention.
  In (a), the sheet-like negative electrode side diffusion layer 13 is disposed. That is, after setting the carbon paper 13a of the negative electrode side diffusion layer 13, a solution for the binder layer 15a is applied onto the carbon paper 13a.
[0030]
  In (b), while the binder layer 15a is undried, the spray 51 is moved as shown by the arrow above the binder layer 15a, and the solution of the negative electrode layer 17 is sprayed from the spray port 52 of the spray 51.
  Thus, the negative electrode layer 17 is formed by applying a solution for the negative electrode layer 17 on the binder layer 15a.
[0031]
  As the solution of the negative electrode layer 17, a solvent having a higher vaporization temperature than the solvent used for the solution for the ion exchange membrane 19 shown in FIG. 2 is used.
  As an example, an alcohol-based solvent is used for the solution for the ion exchange membrane 19 applied on the negative electrode layer 17, and ethylene glycol or N · methyl • having a higher vaporization temperature than the alcohol-based solvent is used for the solution of the negative electrode layer 17. Pyrrolidone (NMP) is used as a solvent.
  The reason why a solvent having a higher vaporization temperature than the solvent used for the solution for the ion exchange membrane 19 is used for the solution of the negative electrode layer 17 will be described later.
[0032]
  In (c), while the negative electrode layer 17 is undried, a solution for the ion exchange membrane 19 is applied onto the negative electrode layer 17 while moving the coater 53 along the upper surface of the negative electrode layer 17 as indicated by the arrow. An exchange membrane 19 is formed.
  Specifically, the blade 53a of the coater 53 is disposed above the negative electrode layer 17 by a predetermined distance and parallel to the upper surface of the negative electrode layer 17, and the blade 53a is moved along the upper surface of the negative electrode layer 17 as indicated by an arrow. However, the ion exchange membrane 19 is formed by leveling the paste (solution) of the ion exchange membrane 19 to a certain thickness with the blade 53a.
[0033]
  As described above, the negative electrode layer 17 and the ion exchange membrane 19 are applied by applying the solution for the ion exchange membrane 19 onto the negative electrode layer 17 while the negative electrode layer 17 is undried while the solution is used for the ion exchange membrane 19. It is possible to effectively mix each other's solution at the boundary.
[0034]
  4 (a) and 4 (b) are explanatory views of a second step showing a method for producing a fuel cell electrode according to the present invention.
  In (a), while the ion exchange membrane 19 is undried, the spray 57 is moved as indicated by the arrow above the ion exchange membrane 19 and the solution of the positive electrode layer 18 is sprayed from the spray port 58 of the spray 57. To do.
  Thus, the positive electrode layer 18 can be formed by applying the solution for the positive electrode layer 18 on the undried ion exchange membrane 19.
[0035]
  As the solution for the positive electrode layer 18, as with the solution for the negative electrode layer 17, a solvent having a higher vaporization temperature than the alcohol solvent used for the solution for the ion exchange membrane 19 is used.
  Here, as an example, ethylene glycol or N.methyl pyrrolidone (NMP) having a higher vaporization temperature than the alcohol solvent is used as the solvent for the positive electrode layer 18 solution.
  The reason why a solvent having a higher vaporization temperature than the solvent used for the solution for the ion exchange membrane 19 is used for the solution of the positive electrode layer 18 will be described later.
[0036]
  In (b), while the positive electrode layer 18 is undried, a solution of the binder layer 16a constituting the positive electrode side diffusion layer 14 (see FIG. 2) is applied on the positive electrode layer 18.
[0037]
  FIGS. 5A and 5B are explanatory diagrams of a third process showing the method for manufacturing a fuel cell electrode according to the present invention.
  In (a), the positive electrode side carbon paper 14a is placed on the binder layer 16a, thereby forming the sheet-like positive electrode side diffusion layer 14 with the binder layer 16a and the carbon paper 14a.
[0038]
  Next, while the negative electrode layer 17, the ion exchange membrane 19, and the positive electrode layer 18 are undried, without applying a load to the negative electrode layer 17, the ion exchange membrane 19, and the positive electrode layer 18, the far-infrared drying apparatus (electromagnetic wave heating) It is dried by heating with a device 55).
  The far-infrared drying device 55 refers to infrared rays having a long wavelength among electromagnetic waves in the infrared region, and is a heating device that uses far-infrared rays in a wavelength region of approximately 50 to 1000 μm in wavelength.
[0039]
  Since the far-infrared drying device 55 can efficiently heat the inside of the object, the ion exchange membrane 19 is obtained by drying the negative electrode layer 17, the ion exchange membrane 18 and the positive electrode layer 18 together with the far-infrared drying device 55. Can be quickly dried from the surface to the inside.
  Accordingly, since the solution of the ion exchange membrane 19 can be prevented from penetrating into the negative electrode layer 17 and the positive electrode layer 18, the solution for the ion exchange membrane 19 can be prevented from closing the voids of the negative electrode layer 17 and the positive electrode layer 18. Can do.
[0040]
  In (b), the negative electrode layer 17, the ion exchange membrane 19 and the positive electrode layer 18 are solidified, and the negative electrode layer 17, the ion exchange membrane 19 and the positive electrode layer 18 are integrally laminated in a solidified state.
  Thereby, the manufacturing process of the electrode 12 for fuel cells is completed.
[0041]
  As described above, according to the method of manufacturing the fuel cell electrode 12, a solution is used for the ion exchange membrane 19, and the solution for the negative electrode layer 17, the solution for the ion exchange membrane 19, and the solution for the positive electrode layer 18 are not used. By applying in a dry state, mixing occurs effectively at each boundary.
  As a result, it is possible to prevent the occurrence of poor adhesion at the boundary between the negative electrode layer 17 and the ion exchange membrane 19 and the boundary between the ion exchange membrane 19 and the positive electrode layer 18. Can keep good.
[0042]
  In addition, since the ion exchange membrane 19 can be handled in the state of solution by using the ion exchange membrane 19 as a solution, it is not necessary to regulate the thickness of the ion exchange membrane 19 from the viewpoint of handling properties. For this reason, the ion exchange membrane 19 can be made thin, and the fuel cell electrode 12 can be made thin to achieve miniaturization.
[0043]
  In addition, according to the method of manufacturing the fuel cell electrode 12, the solution for the ion exchange membrane 19 is prevented from penetrating the electrode layer 17 and the positive electrode layer 18 to block the gaps in the electrode layer 17 and the positive electrode layer 18. be able to. Therefore, the generated water generated by the power generation of the fuel cell is led from the gaps in the negative and positive electrode layers 17 and 18 (particularly the positive electrode layer 18) to the positive electrode side diffusion layer 14 (carbon paper 14a and binder layer 16a) to be positive electrode side diffusion layer. Since it can discharge | emit suitably outside from 14 space | gap, the density | concentration overvoltage produced in a fuel cell can be restrained low.
[0044]
  Further, by using a solvent having a higher vaporization temperature than the solvent used for the solution for the ion exchange membrane 19 for the solution of the negative electrode layer 17 and the positive electrode layer 18, the ion exchange membrane 19 is given priority over the negative electrode layer 17 and the positive electrode layer 18. Can be surely dried.
  Thereby, the solution for the ion exchange membrane 19 is further effectively prevented from penetrating into the negative electrode layer 17 and the positive electrode layer 18, and the solution for the ion exchange membrane 19 penetrates into the negative electrode layer 17 and the positive electrode layer 18. Thus, it is possible to prevent the gap between the negative electrode layer 17 and the positive electrode layer 18 from being blocked.
[0045]
  6A and 6B are graphs illustrating the relationship between the void volume and the concentration concentration overvoltage of the fuel cell electrode according to the present invention. In the graph of (a), the vertical axis represents the void volume (cm³/ G), and the graph of (b) shows the concentration overvoltage (mV) of the electrode on the vertical axis.
[0046]
  In the graph,Reference exampleIs a solution in which an alcohol solvent is used for the solution for the ion exchange membrane 19, and ethylene glycol or N.methyl pyrrolidone (NMP) having a higher vaporization temperature than the alcohol solvent is used for the solution of the positive electrode layer 18 as a solvent. is there.
  Also,Reference exampleIn this example, a normal hot air drying apparatus is used for drying the negative electrode layer 17, the ion exchange membrane 19 and the positive electrode layer 18.
  That is,Reference exampleIs a part of the above-described embodiment (ethylene glycol or N.methyl pyrrolidone (NMP)).
[0047]
  ExampleIsReference exampleAnd a far-infrared dryer 55 is used to dry the negative electrode layer 17, the ion exchange membrane 19 and the positive electrode layer 18, as well as the solvent ((ethylene glycol or N · methyl pyrrolidone (NMP))). That is,ExampleCorresponds to the embodiment described above
  The comparative example isReference example,ExampleWithout using any other solvent ((ethylene glycol or N-methyl-pyrrolidone (NMP)))ExampleA normal hot air dryer is used without using the far-infrared dryer.
[0048]
  In the graph of (a), the comparative example has the smallest void volume of the positive electrode layer 18,Reference exampleCan ensure a larger void volume of the positive electrode layer 18 than the comparative example,ExampleIsReference exampleA larger void volume of the positive electrode layer 18 can be secured.
  That is,ExampleCan secure the largest porosity of the positive electrode layer 18.
[0049]
  In the graph of (b), since the void volume of the positive electrode layer 18 is the smallest in the comparative example, the concentration overvoltage of the fuel cell is the largest, and the voltage drop of the fuel cell is the largest.
  Reference exampleSince the void volume of the positive electrode layer 18 is larger than that of the comparative example, the concentration overvoltage of the fuel cell becomes smaller than that of the comparative example, and the voltage drop of the fuel cell can be suppressed smaller than that of the comparative example.
  ExampleIs the void volume of the positive electrode layer 18Reference exampleThe concentration overvoltage of the fuel cell isReference exampleAs a result, the voltage drop of the fuel cell can be minimized.
[0050]
  ThisReference exampleAs described above, an alcohol solvent is used for the solution for the ion exchange membrane 19, and ethylene glycol or N.methyl pyrrolidone (NMP) having a higher vaporization temperature than the alcohol solvent is used as the solvent for the positive electrode layer 18. Thus, it is understood that the voltage drop of the fuel cell can be suppressed relatively suitably.
[0051]
  Also,Examplelike,Reference exampleThe solvent (ethylene glycol or N.methyl pyrrolidone (NMP)) is used, and the negative electrode layer 17, the ion exchange membrane 19 and the positive electrode layer 18 are dried with a far-infrared dryer 55, thereby reducing the voltage of the fuel cell. It can be seen that it can be minimized most efficiently.
[0052]
  In the above-described embodiment, the example in which the negative electrode layer 17 is disposed below and the positive electrode layer 18 is disposed above has been described. However, the same applies to the case where the negative electrode layer 17 is disposed above and the positive electrode layer 18 is disposed below. The effect of can be obtained.
[0053]
  Moreover, although the said embodiment demonstrated the example which uses the far-infrared drying apparatus 55, it can replace with the far-infrared drying apparatus 55, for example, can also use a microwave drying apparatus.
  The microwave dryer is approximately 1 × 10 in wavelength.⁴~ 30x10⁴This is a heating device using a microwave having a wavelength region of μm.
  Further, the wavelength is not limited to the far-infrared dryer 55 or the microwave, and the wavelength is 50 to 30 × 10.⁴A similar effect can be obtained by using a heating means using a μm electromagnetic wave.
[0054]
  Moreover, although the said embodiment demonstrated the example which heat-drys the ion exchange membrane 19 only with the far-infrared drying apparatus 55 (electromagnetic wave drying apparatus), it uses combining the far-infrared drying apparatus 55 and a hot air drying apparatus. Is also possible.
[0055]
  Furthermore, although the said embodiment demonstrated the example which apply | coats the solution of the negative electrode layer 17 on the upper surface of the binder layer 15a using the spray 51, application | coating of the negative electrode layer 17 is not restricted to the spray 51, Others, such as an inkjet system, etc. It is also possible to adopt.
[0056]
  Moreover, although the said embodiment demonstrated the example which apply | coats the solution for the ion exchange membranes 19 on the upper surface of the negative electrode layer 17 using the coater 53, apply | coating the solution for the ion exchange membranes 19 with another application | coating means. Is also possible.
[0057]
  Furthermore, in the above-described embodiment, the example in which the solution of the positive electrode layer 18 is applied to the upper surface of the ion exchange membrane 19 using the spray 57 has been described. However, the application of the positive electrode layer 18 is not limited to the spray 57, Other types are also possible.
[0058]
  Here, spray and inkjet are the same in that the solution is applied in a spray form. Although the spray has a relatively wide spray range and can shorten the application time, a masking process is required to secure an uncoated part. In general, it is difficult to recover the solution attached to the masking unit.
[0059]
  On the other hand, since the application range of the ink jet can be narrowed down accurately, it is not necessary to perform a masking process on the uncoated part, and the solution can be used effectively. However, since the inkjet application range is narrow, the application speed is inferior to that of spray.
[0060]
  In the above embodiment, an alcohol-based solvent is used for the solution for the ion exchange membrane 19, and ethylene glycol or N • methyl • having a higher vaporization temperature than the alcohol-based solvent for both the negative electrode layer 17 and the positive electrode layer 18. Although an example using pyrrolidone (NMP) as a solvent has been described, the present invention is not limited thereto, and ethylene glycol or N · methyl pyrrolidone (NMP) having a higher vaporization temperature than that of an alcohol-based solvent is used as a solvent only in the positive electrode layer 18 solution. The same effect can be obtained even when used as.
[0061]
  The reason is that when the fuel cell is used to generate an electric current, the generated water passes through the positive electrode side diffusion layer (carbon paper) and is discharged to the outside of the fuel cell, so that a gap is secured in the positive electrode layer 18. This is because the generated water can be discharged to the outside of the fuel cell.
[0062]
【The invention's effect】
  The present invention exhibits the following effects by the above configuration.
  According to the first aspect, when a solution is used for the ion exchange membrane and the electrode solution and the ion exchange membrane solution are applied in an undried state, mixing occurs at the boundary.
  Thereby, it is possible to prevent a poor adhesion portion from occurring at the boundary between each layer of the pair of electrodes and the ion exchange membrane, so that the reaction efficiency in the ion exchange membrane can be kept good.
  As a result, the quality of the fuel cell electrode can be stabilized, and the productivity can be increased.
[0063]
  In addition, since the ion exchange membrane can be handled in a solution state by using the ion exchange membrane as a solution, it is not necessary to regulate the thickness of the ion exchange membrane from the viewpoint of handling properties. For this reason, the ion exchange membrane can be made thin, and the fuel cell electrode can be made thin, so that the fuel cell can be miniaturized.
[0064]
  Also, one electrode layer, the ion exchange membrane and the other electrode layer are dried using electromagnetic heating. By drying by electromagnetic wave heating, the inside of the ion exchange membrane can be efficiently heated and dried. Thus, by drying one electrode layer, the ion exchange membrane and the other electrode layer by electromagnetic heating, the ion exchange membrane can be quickly dried from the surface to the inside.
  Thereby, it can suppress that the solution of an ion exchange membrane osmose | permeates one electrode layer or the other electrode layer.
[0065]
  By suppressing the solution for the ion exchange membrane from penetrating into the electrode layer, it is possible to prevent the gap of the electrode layer from being blocked with the solution for the ion exchange membrane. Therefore, the generated water generated by the power generation can be guided from the gap of the electrode layer to the diffusion layer and suitably discharged from the gap of the diffusion layer, so that the concentration overvoltage generated in the fuel cell can be suppressed low.
[0066]
  furtherClaim1In the electrode solution, by using a solvent having a higher vaporization temperature than the solvent used in the ion exchange membrane solution, the ion exchange membrane can be reliably dried in preference to the electrode layer. Therefore, it is possible to more efficiently suppress the penetration of the solution for the ion exchange membrane into the electrode layer and to reliably prevent the gap of the electrode layer from being blocked with the solution for the ion exchange membrane. The concentration overvoltage generated in the above can be further reduced.
  The electrode layer solution is characterized in that ethylene glycol or N · methyl pyrrolidone is used as a solvent.
[Brief description of the drawings]
FIG. 1 is an exploded perspective view showing a fuel cell including a fuel cell electrode according to the present invention.
FIG. 2 is an explanatory view showing a fuel cell electrode according to the present invention.
FIG. 3 is an explanatory diagram of a first process showing a method of manufacturing a fuel cell electrode according to the present invention.
FIG. 4 is an explanatory diagram of a second step showing a method of manufacturing a fuel cell electrode according to the present invention.
FIG. 5 is an explanatory diagram of a third step showing a method of manufacturing a fuel cell electrode according to the present invention.
FIG. 6 is a graph illustrating the relationship between the void volume and the concentration concentration overvoltage of the fuel cell electrode according to the present invention.
FIG. 7 is an explanatory diagram for explaining a conventional fuel cell.
FIG. 8 is an explanatory view showing a fuel cell electrode constituting a conventional fuel cell.
[Explanation of symbols]
  DESCRIPTION OF SYMBOLS 11 ... Fuel cell, 12 ... Electrode for fuel cells, 13 ... Negative electrode side diffusion layer (sheet), 14 ... Positive electrode side diffusion layer, 17 ... Negative electrode layer (one electrode layer), 18 ... Positive electrode layer (the other electrode layer) , 19 ... ion exchange membrane.

Claims (2)

On the sheet-like diffusion layer, a solution for either the positive or negative electrode layer constituting the fuel cell, in which a catalyst in which platinum or a platinum-ruthenium alloy is supported on the carbon surface is mixed, Applying and forming one electrode layer;
A process of forming an ion exchange membrane by applying a solution for an ion exchange membrane on the electrode layer while one electrode layer is undried;
While the ion-exchange membrane is undried, a solution for either the positive or negative electrode layer on the ion-exchange membrane, with a platinum-ruthenium alloy or a catalyst carrying platinum supported on the carbon surface was mixed. Applying a solution to form the other electrode layer;
The other electrode layer, the ion exchange membrane 及 beauty the one electrode layer method for manufacturing a fuel cells consisting of a solidification step of solidifying and Drying,
The electrode layer solution uses a solvent having a higher vaporization temperature than the solvent used for the ion exchange membrane solution,
The method of manufacturing a fuel cell, wherein the drying in the solidification step is performed by electromagnetic wave heating . The solution for the electrode layer, the manufacturing method of the fuel cells according to claim 1, wherein the ethylene glycol or N · methyl pyrrolidone is obtained using as solvent.

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