Fuel cell manufacturing method

Abstract

The present invention provides a method for manufacturing a fuel cell cell 10 in which the permeability of the gas diffusion layer 14a is improved. [Solution] The manufacturing method for the fuel cell cell 10 includes a preparation step S100 in which an electrolyte membrane 11, a gas diffusion layer 14a, and a catalyst layer 12a are prepared. The manufacturing method for the fuel cell cell 10 involves applying heat to the intermediate carbon layer 13X to melt the resin material while applying pressure to the intermediate carbon layer 13X from the gas diffusion layer 14a side and applying pressure to the intermediate carbon layer 13X from the joint 11A side. The manufacturing method for the fuel cell cell 10 includes a cooling step S130 in which the intermediate carbon layer 13X is cooled while maintaining the application of pressure to the intermediate carbon layer 13X from the catalyst layer 12a side and applying pressure to the intermediate carbon layer 13X from the gas diffusion layer 14a side.

Description

[Technical Field]

[0001] This disclosure relates to a method for manufacturing a fuel cell. [Background technology]

[0002] Conventionally, fuel cell cells comprising an electrolyte membrane, a first catalyst layer, a second catalyst layer, a first gas diffusion layer, and a second gas diffusion layer have been proposed (see, for example, Patent Document 1). The first catalyst layer is formed as a film on one side in the thickness direction relative to the electrolyte membrane. The second catalyst layer is formed as a film on the other side in the thickness direction relative to the electrolyte membrane. The first gas diffusion layer is formed as a film on one side in the thickness direction relative to the first catalyst layer. The second gas diffusion layer is formed as a film on the other side in the thickness direction relative to the second catalyst layer.

[0003] A fuel cell manufacturing method comprises a coating step of forming a first carbon intermediate layer by applying an ink solution containing carbon powder, fluororesin, and a dispersant to the other side in the thickness direction of a first gas diffusion layer. Furthermore, the fuel cell manufacturing method comprises a bonding step of bonding the first catalyst layer to the first carbon intermediate layer by attaching the first catalyst layer to the first carbon intermediate layer, which is in a wet state with the ink solution, after the coating step. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2003-282079 [Overview of the Initiative] [Problems that the invention aims to solve]

[0005] In the fuel cell manufacturing method described above, as stated above, ink is applied to the other side of the first gas diffusion layer in the thickness direction in order to form a first carbon intermediate layer on the other side of the first gas diffusion layer in the thickness direction. The first gas diffusion layer is made of a porous material having multiple pores. As a result, the ink seeps into the first gas diffusion layer and the ink passes through to the other side of the first gas diffusion layer. Consequently, carbon powder and fluororesin remain inside the gas diffusion layer. Therefore, the carbon powder and fluororesin prevent gases such as air or hydrogen gas from flowing through the gas diffusion layer. In other words, the permeability of the gas diffusion layer, which allows gas to pass through, decreases due to the ink.

[0006] In view of the above points, this disclosure aims to provide a method for manufacturing a fuel cell that ensures the permeability of the gas diffusion layer. [Means for solving the problem]

[0007] According to one aspect of this disclosure, in a method for manufacturing a fuel cell, An electrolyte membrane (11) formed in a membrane-like manner, and gas diffusion layers (14a, 14b) formed in a membrane-like manner that extend in an intersecting direction (Yb) intersecting the thickness direction (Ya) of the electrolyte membrane, which diffuse gas, Preparation step (S100) to prepare catalyst layers (12a, 12b) which are arranged between the electrolyte membrane and the gas diffusion layer in the thickness direction, formed in a film shape along the electrolyte membrane, bonded to the electrolyte membrane to form a bonded body (11A) together with the electrolyte membrane, and generate a reaction related to power generation using the gas diffused by the gas diffusion layer, A hot-pressure bonding process (S120) is performed in which an intermediate carbon layer (13X, 13Y), which is made of a solid material containing carbon and resin material and formed in granular or powder form, is placed between the gas diffusion layer and the catalyst layer, and while pressure is applied to the intermediate carbon layer from the gas diffusion layer side and pressure is applied to the intermediate carbon layer from the catalyst layer side, heat is applied to the intermediate carbon layer to melt the resin material, The process includes a cooling step (S130) in which, after the hot-pressure bonding step, the intermediate carbon layer is cooled while maintaining pressure applied from the gas diffusion layer side to the intermediate carbon layer and from the catalyst layer side, thereby solidifying the resin material to bond the gas diffusion layer and the intermediate carbon layer, and also bonding the intermediate carbon layer and the catalyst layer.

[0008] Therefore, no ink is used in the fuel cell manufacturing method. As a result, the ink does not seep into the gas diffusion layer. Consequently, the permeability of the gas diffusion layer is not reduced due to the ink within the gas diffusion layer. Therefore, it is possible to provide a fuel cell manufacturing method that ensures the permeability of the gas diffusion layer. Furthermore, according to one aspect of this disclosure, the intermediate carbon layer is cooled while simultaneously applying pressure from the gas diffusion layer to the intermediate carbon layer and maintaining pressure from the catalyst layer to the intermediate carbon layer. This allows for improvement of both the strength of the intermediate carbon layer itself and the bonding strength in a short time. Bonding strength refers to the bonding strength between the gas diffusion layer and the intermediate carbon layer, and the bonding strength between the intermediate carbon layer and the catalyst layer. The reference numerals in parentheses attached to each component indicate an example of the correspondence between that component and the specific components described in the embodiments described later. [Brief explanation of the drawing]

[0009] [Figure 1] This figure shows the overall configuration of a fuel cell in the first embodiment of the present disclosure and illustrates the laminated structure of a gas diffusion layer, a water-repellent layer, and a catalyst layer. [Figure 2] Figure 1 shows the layered structure of the gas diffusion layer, water-repellent layer, and catalyst layer in the fuel cell cell of the first embodiment. [Figure 3] Figure 1 is a diagram illustrating the manufacturing process for producing the water-repellent layer of the fuel cell cell in the first embodiment, and shows the gas diffusion layer alone. [Figure 4]Figure 1 is a schematic diagram illustrating the manufacturing process for producing the water-repellent layer of the fuel cell cell in the first embodiment, and shows the process of forming an intermediate carbon layer on the upper surface of the gas diffusion layer. [Figure 5] Figure 1 is a diagram illustrating the process for manufacturing the water-repellent layer of the fuel cell cell in the first embodiment, and illustrates the heating of the intermediate carbon layer while applying pressure from the catalyst layer to the intermediate carbon layer and from the gas diffusion layer to the intermediate carbon layer. [Figure 6] Figure 1 is a diagram illustrating the process for manufacturing the water-repellent layer of a fuel cell cell in the first embodiment, illustrating the process of cooling the intermediate carbon layer while simultaneously applying pressure from the catalyst layer to the intermediate carbon layer and maintaining pressure from the gas diffusion layer to the intermediate carbon layer. [Figure 7] Figure 1 is a schematic diagram illustrating the process of manufacturing the water-repellent layer of the fuel cell in the first embodiment, and is a diagram illustrating the process of removing the cooling press member from the fuel cell to complete the fuel cell. [Figure 8] Figure 1 is a flowchart illustrating the manufacturing process of a fuel cell cell in the first embodiment, and is a diagram illustrating the hot pressing process for forming the water-repellent layer and the press cooling process. [Figure 9] This is a schematic diagram illustrating the hot pressing process, the press-cooling process, and the process of removing the backsheet from the electrolyte membrane in the manufacturing process of the fuel cell in the first embodiment shown in Figure 1. [Figure 10] This is a schematic diagram illustrating the manufacturing process of the intermediate carbon layer of a fuel cell cell in the first embodiment. [Figure 11] Figure 10 illustrates how the ink used in the manufacturing process of the intermediate carbon layer of a fuel cell, as shown in the proportional relationship, seeps into the gas diffusion layer and remains in the gas diffusion layer. [Figure 12] Figure 10 is a perspective view illustrating how air bypasses the constriction and flows into the gas diffusion layer in the multiple airflow channels of a fuel cell in a proportional relationship. [Figure 13]FIG. 10 is a perspective view for explaining that in one air flow path of a fuel cell in the comparative example, air bypasses a throttle portion and flows into a gas diffusion layer. [Figure 14] FIG. 10 is a schematic diagram for explaining that in one air flow path of a fuel cell in the comparative example, the air that bypasses the throttle portion is suppressed from passing through the gas diffusion layer by an ink liquid. [Figure 15] FIG. 1 is a diagram for explaining that the in-plane air permeability of the gas diffusion layer of the fuel cell in the first embodiment is improved as compared with the in-plane air permeability of the gas diffusion layer of the fuel cell in the comparative example. [Figure 16] FIG. 1 is a diagram for explaining that the manufacturing time of the fuel cell in the first embodiment is shortened as compared with the manufacturing time of the fuel cell in the comparative example. [Figure 17] FIG. 1 is a diagram for explaining that the bonding strength is improved by maintaining the application of pressure to the intermediate carbon layer after thermocompression bonding in the manufacturing process of the fuel cell in the first embodiment. [Figure 18] FIG. 1 is a diagram for explaining that the bonding strength changes depending on the temperature of the intermediate carbon layer when releasing the application of pressure to the intermediate carbon layer after thermocompression bonding in the manufacturing process of the fuel cell in the first embodiment. [Figure 19] FIG. 1 is a diagram for explaining the temperature and pressure during thermocompression bonding in the manufacturing process of the fuel cell in the first embodiment. [Figure 20] FIG. 21 is a cross-sectional view showing the overall configuration of a fuel cell in the second embodiment of the present disclosure, and is a diagram for explaining the arrangement structure of a gas diffusion layer, a water-repellent layer, and a catalyst layer. [Figure 21] FIG. 24 is a schematic diagram for explaining the manufacturing process of the fuel cell in the second embodiment of FIG. 20.

BEST MODE FOR CARRYING OUT THE INVENTION

[0010] The embodiments of this disclosure will be described below with reference to the drawings. In the following embodiments, parts that are the same or equivalent to each other are denoted by the same reference numerals in the drawings in order to simplify the explanation. (First Embodiment) Next, the fuel cell cell 10 of this first embodiment will be described with reference to Figure 1 and the like. Figure 1 is a cross-sectional view showing the detailed configuration of the fuel cell cell 10.

[0011] Figure 2 is a cross-sectional view showing the schematic configuration of a fuel cell 10. Multiple fuel cell cells 10 in Figure 1 are stacked to form a solid polymer fuel cell for vehicles, creating a stack structure. The solid polymer fuel cell is configured as a series connection in which multiple fuel cell cells 10 are electrically connected in series. As shown in Figures 1 and 2, the fuel cell cell 10 comprises an electrolyte membrane 11, catalyst layers 12a, 12b, water-repellent layers 13a, 13b, gas diffusion layers 14a, 14b, and separators 15a, 15b.

[0012] The electrolyte membrane 11 is formed in a film-like manner from a polymer material such as a fluorine carbide-based or hydrocarbon-based material that has water content. The electrolyte membrane 11 is an ion exchange membrane composed of an ionomer and possesses proton conductivity. For the purposes of this explanation, the thickness direction of the electrolyte membrane 11 will be referred to as the stacking direction Ya, and the direction intersecting (for example, orthogonal to) the stacking direction Ya will be referred to as the plane direction (i.e., the intersecting direction) Yb. The catalyst layer 12a is positioned on one side of the electrolyte membrane 11 in the stacking direction Ya. The catalyst layer 12a is formed in a film-like manner that extends along the electrolyte membrane 11 in the plane direction Yb.

[0013] The catalyst layer 12a is bonded to one side of the electrolyte membrane 11 in the stacking direction Ya. Together with the electrolyte membrane 11, the catalyst layer 12a constitutes the assembly 11A. The catalyst layer 12b is located on the other side of the electrolyte membrane 11 in the stacking direction Ya. The catalyst layer 12b is formed as a film that extends in the planar direction Yb along the electrolyte membrane 11. The catalyst layer 12b is bonded to the other side of the electrolyte membrane 11 in the stacking direction Ya.

[0014] Catalyst layers 12a and 12b are each composed of a catalytic substance (e.g., platinum particles), a supporting carbon that supports the substance, and an ionomer that coats the supporting carbon. Catalyst layer 12a reacts oxygen gas in the air with protons and electrons to produce water, as shown in Equation 1. Catalyst layer 12b decomposes hydrogen gas into protons (i.e., hydrogen ions) and electrons, as shown in Equation 2.

[0015] 2H + +1 / 2·O 2 +2e - →H 2 O ···(Equation 1) H 2 →2H + +2e - ...(Equation 2) Thus, catalyst layer 12a constitutes the cathode side electrode that generates electricity-related reactions using oxygen gas from the air. Catalyst layer 12b constitutes the anode side electrode that generates electricity-related reactions using hydrogen gas.

[0016] The water-repellent layer 13a is positioned on one side of the catalyst layer 12a in the lamination direction Ya. The water-repellent layer 13a is formed as a film that extends in the planar direction Yb along the catalyst layer 12a, with the lamination direction Ya being the thickness direction. The water-repellent layer 13a is composed of a porous material such as carbon and has water-repellent properties that allow water produced in the catalyst layer 12a to pass through without condensation. Furthermore, the water-repellent layer 13a has permeability that allows air and water to pass through, as well as electron conductivity.

[0017] The gas diffusion layer 14a is positioned on one side of the lamination direction Ya relative to the water-repellent layer 13a. The gas diffusion layer 14a is formed as a film that extends in the planar direction Yb along the water-repellent layer 13a, with the lamination direction Ya being the thickness direction. The gas diffusion layer 14a diffuses air and supplies the catalyst layer 12a through the water-repellent layer 13a. The gas diffusion layer 14a is composed of a porous material (e.g., carbon paper, carbon cloth) that has air permeability and electron conductivity.

[0018] The water-repellent layer 13b is positioned on the other side of the stacking direction Ya relative to the catalyst layer 12b. The water-repellent layer 13b is formed as a film that extends in the planar direction Yb along the catalyst layer 12b, with the stacking direction Ya being the thickness direction. The water-repellent layer 13b is composed of a porous material such as carbon and has water-repellent properties that allow water produced in the catalyst layer 12a to pass through without condensation. The water-repellent layer 13b has permeability that allows hydrogen gas and water to pass through, as well as electron conductivity.

[0019] The gas diffusion layer 14b is positioned on the other side of the lamination direction Ya relative to the water-repellent layer 13b. The gas diffusion layer 14b is formed as a film that extends in the planar direction Yb along the water-repellent layer 13b, with the lamination direction Ya being the thickness direction. The gas diffusion layer 14b diffuses hydrogen gas and supplies it to the catalyst layer 12b through the water-repellent layer 13b. The gas diffusion layer 14b is composed of a porous material (e.g., carbon paper, carbon cloth) that has hydrogen gas permeability and electronic conductivity.

[0020] Separator 15a is positioned on one side of the stacking direction Ya relative to the gas diffusion layer 14a. Separator 15a is made of, for example, a conductive carbon substrate. Multiple air channels 16a are formed in the portion of separator 15a facing the gas diffusion layer 14a through which air flows. Separator 15b is positioned on the other side of the stacking direction Ya relative to the gas diffusion layer 14b. Separator 15b is made of, for example, a conductive carbon substrate. Multiple hydrogen channels 16b are formed in the portion of separator 15b facing the gas diffusion layer 14b through which hydrogen gas flows.

[0021] Next, the operation of the fuel cell cell 10 of this embodiment will be described. First, hydrogen gas supplied from an external gas tank is supplied to a plurality of hydrogen channels 16b, and the hydrogen gas flows through the plurality of hydrogen channels 16b. The hydrogen gas flows from the plurality of hydrogen channels 16b into the gas diffusion layer 14b. This incoming hydrogen gas is diffused by the gas diffusion layer 14b. This diffused hydrogen gas flows through the water-repellent layer 13b to the catalyst layer 12b. In this catalyst layer 12b, as shown in equation 2 above, the hydrogen gas is decomposed into protons and electrons.

[0022] Electrons move from the catalyst layer 12b to an external electrical load (e.g., an electrical device such as an in-vehicle air conditioning system) through the water-repellent layer 13b, the gas diffusion layer 14b, and the separator 15b. These moved electrons then move from the external electrical load to the catalyst layer 12a through the separator 15a, the gas diffusion layer 14a, and the water-repellent layer 13a. Meanwhile, protons generated in the catalyst layer 12b are supplied to the catalyst layer 12a through the electrolyte membrane 11.

[0023] Furthermore, air (specifically, oxygen gas) supplied from the outside is supplied to multiple air channels 16a, and air flows through the multiple air channels 16a. The air flows from the multiple air channels 16a into the gas diffusion layer 14a. This incoming air is diffused by the gas diffusion layer 14a. This diffused air flows through the water-repellent layer 13a to the catalyst layer 12a. In this catalyst layer 12a, as shown in Equation 1 above, oxygen gas, protons, and electrons contained in the air react to produce water.

[0024] In this way, some of the water generated in the catalyst layer 12a is discharged to the outside through the water-repellent layer 13a and the gas diffusion layer 14a. Of the water generated in the catalyst layer 12a, the remaining water, other than the portion discharged to the outside through the water-repellent layer 13a and the gas diffusion layer 14a, is discharged to the outside through the electrolyte membrane 11, catalyst layer 12b, water-repellent layer 13b, and gas diffusion layer 14b. Next, an outline of the manufacturing method for the fuel cell cell 10 of this embodiment will be described.

[0025] The manufacturing method of the fuel cell cell 10 in this embodiment and the fuel cell cell manufacturing method in Patent Document 1 mainly differ in the manufacturing methods of the water-repellent layers 13a and 13b. In contrast, before describing the specific manufacturing method of the fuel cell cell 10 in this embodiment, the manufacturing method of the water-repellent layer 13a of the fuel cell cell 10 in this embodiment will be described with reference to Figures 3, 4, 5, 6, and 7. Figures 3, 4, 5, 6, and 7 are schematic diagrams showing the manufacturing process of the water-repellent layer 13a.

[0026] First, as shown in Figure 3, a gas diffusion layer 14a is prepared, and then, as shown in Figure 4, a powder solid material containing carbon 13d and resin material 13c is blown from the powder ejector 100 onto one surface of the gas diffusion layer 14a. This forms an intermediate carbon layer 13X containing carbon 13d and resin material 13c on one surface of the gas diffusion layer 14a. Here, carbon 13d is a powder solid material. The resin material 13c is, for example, a solid material made of powder fluororesin.

[0027] Next, a bonded assembly 11A, to which the catalyst layer 12a and the electrolyte membrane 11 are joined, is prepared, and as shown in Figure 5, the bonded assembly 11A is mounted on one side of the stacking direction Ya relative to the intermediate carbon layer 13X. As a result, in Figure 5, the electrolyte membrane 11, catalyst layer 12a, intermediate carbon layer 13X, and gas diffusion layer 14a are arranged in that order from one side to the other in the stacking direction Ya.

[0028] Next, the thermo-pressure bonding member 110a applies pressure to the electrolyte membrane 11, catalyst layer 12a, intermediate carbon layer 13X, and gas diffusion layer 14a from one side in the lamination direction Ya. In addition, the thermo-pressure bonding member 110b applies pressure to the electrolyte membrane 11, catalyst layer 12a, intermediate carbon layer 13X, and gas diffusion layer 14a from the other side in the lamination direction Ya. Furthermore, the thermo-pressure bonding members 110a and 110b apply heat to the electrolyte membrane 11, catalyst layer 12a, intermediate carbon layer 13X, and gas diffusion layer 14a.

[0029] As a result, as shown by arrows F1 and F2 in Figure 5, pressure is applied to the intermediate carbon layer 13X from the gas diffusion layer 14a side and to the intermediate carbon layer 13X from the joint 11A side, while heat is applied to the intermediate carbon layer 13X to melt the resin material. Here, the heat resistance temperature of the ionomer contained in the electrolyte membrane 11 is defined as the first heat resistance temperature, and the heat resistance temperature of the ionomer contained in the catalyst layer 12a is defined as the second heat resistance temperature. In this embodiment, the intermediate carbon layer 13X is heated by the thermo-pressure bonding members 110a and 110b so that the temperature of the electrolyte membrane 11 falls below the first heat resistance temperature and the temperature of the catalyst layer 12a falls below the second heat resistance temperature.

[0030] This prevents damage to the ionomer contained in the electrolyte membrane 11 and the ionomer contained in the catalyst layer 12a. Subsequently, the cooling press members 120a and 120b apply pressure to the electrolyte membrane 11, catalyst layer 12a, intermediate carbon layer 13X, and gas diffusion layer 14a from one side in the stacking direction Ya while maintaining pressure from the other side in the stacking direction Ya. In addition, the cooling press members 120a and 120b cool the electrolyte membrane 11, catalyst layer 12a, intermediate carbon layer 13X, and gas diffusion layer 14a.

[0031] Therefore, as shown by arrows F3 and F4 in Figure 6, pressure is applied to the intermediate carbon layer 13X from the gas diffusion layer 14a side while simultaneously maintaining pressure on the intermediate carbon layer 13X from the joint 11A side, and the intermediate carbon layer 13X is cooled to solidify the resin material. As a result, a water-repellent layer 13a is formed between the gas diffusion layer 14a and the catalyst layer 12a. Consequently, the resin material of the water-repellent layer 13a and the ionomer of the catalyst layer 12a are bonded together, thereby bonding the water-repellent layer 13a and the catalyst layer 12a. Furthermore, the water-repellent layer 13a and the gas diffusion layer 14a are bonded together.

[0032] Next, as shown in Figure 7, the cooling press members 120a and 120b are separated from the electrolyte membrane 11, catalyst layer 12a, water-repellent layer 13a, and gas diffusion layer 14a. As a result, the electrolyte membrane 11, catalyst layer 12a, water-repellent layer 13a, and gas diffusion layer 14a are integrated into one unit. Next, the specific manufacturing method of the fuel cell cell 10 of this embodiment will be described with reference to Figures 8 and 9. Figure 8 is a flowchart showing the overall manufacturing process of the fuel cell cell 10. Figure 9 is a schematic diagram to assist in the explanation of the manufacturing process in Figure 8.

[0033] First, in the manufacturing process of step S100, as shown in Figure 9, a roll 200 on which the strip-shaped bonded body 11A is wound, a roll 210 on which the strip-shaped gas diffusion layer 14a is wound, and the gas diffusion layer 14b are prepared. A back sheet 11b is attached to one side of the electrolyte membrane 11 of the bonded body 11A (for example, the other side in the stacking direction Ya). Therefore, in the bonded body 11A, the electrolyte membrane 11 is positioned between the back sheet 11b and the catalyst layer 11a.

[0034] Here, the electrolyte membrane 11 has low rigidity and cannot maintain its shape on its own; its shape is maintained by the backsheet 11b. The backsheet 11b is made of a resin material and is formed in the form of a thin film. In the manufacturing process of this embodiment, thermo-pressure joining members 110a and 110b are provided for heating the electrolyte membrane 11, catalyst layer 12a, intermediate carbon layer 13X, and gas diffusion layer 14a under pressure.

[0035] Furthermore, in the manufacturing process of this embodiment, cooling press members 120a and 120b are provided for cooling the electrolyte membrane 11, catalyst layer 12a, intermediate carbon layer 13X, and gas diffusion layer 14a under pressure. In the manufacturing process of this embodiment, sheet separators 121a and 121b are provided for peeling the back sheet 11b from the electrolyte membrane 11. Next, in the manufacturing process of step S110, a solid powder material containing carbon 13d and resin material 13c is blown from the powder ejector 100 onto the upper surface of the gas diffusion layer 14a that is unrolled from the roll 210.

[0036] This forms an intermediate carbon layer 13X on the upper surface of the gas diffusion layer 14a. In addition, the assembled body 14A, which is unwound from the roll 200, is laminated on the upper surface of the intermediate carbon layer 13X. As a result, the backsheet 11b, electrolyte membrane 11, catalyst layer 12a, intermediate carbon layer 13X, and gas diffusion layer 14a are laminated in the order from top to bottom.

[0037] Next, in the hot pressing process of step S120, the back sheet 11b, electrolyte membrane 11, catalyst layer 12a, intermediate carbon layer 13X, and gas diffusion layer 14a are passed between the hot-pressure bonding members 110a and 110b. At this time, the hot-pressure bonding member 110a applies pressure to the back sheet 11b, electrolyte membrane 11, catalyst layer 12a, intermediate carbon layer 13X, and gas diffusion layer 14a from one side in the stacking direction Ya. In addition, the hot-pressure bonding member 110b applies pressure to the back sheet 11b, electrolyte membrane 11, catalyst layer 12a, intermediate carbon layer 13X, and gas diffusion layer 14a from the other side in the stacking direction Ya.

[0038] In addition, the hot-pressure bonding members 110a and 110b apply heat to the backsheet 11b, electrolyte membrane 11, catalyst layer 12a, intermediate carbon layer 13X, and gas diffusion layer 14a. As a result, pressure is applied to the intermediate carbon layer 13X from the gas diffusion layer 14a side and to the intermediate carbon layer 13X from the catalyst layer 12a side, while heat is applied to the intermediate carbon layer 13X to melt the resin material. Next, in the manufacturing process of step S130, as a press cooling process, the back sheet 11b, electrolyte membrane 11, catalyst layer 12a, intermediate carbon layer 13X, and gas diffusion layer 14a are passed between the cooling press members 120a and 120b.

[0039] At this time, the cooling press members 120a and 120b maintain a state in which pressure is applied to the backsheet 11b, electrolyte membrane 11, catalyst layer 12a, intermediate carbon layer 13X, and gas diffusion layer 14a from one side in the stacking direction Ya, while simultaneously applying pressure from the other side in the stacking direction Ya. In addition, the cooling press member 120a cools the backsheet 11b, electrolyte membrane 11, catalyst layer 12a, intermediate carbon layer 13X, and gas diffusion layer 14a. Furthermore, the cooling press member 120b cools the backsheet 11b, electrolyte membrane 11, catalyst layer 12a, intermediate carbon layer 13X, and gas diffusion layer 14a.

[0040] In this embodiment, in the manufacturing process of step S130, the intermediate carbon layer 13X is cooled by cooling press members 120a and 120b so that the temperature of the resin material constituting the intermediate carbon layer 13X becomes lower than the melting point of the resin material. In this embodiment, the resin material constituting the intermediate carbon layer 13X has a melting point lower than that of the electrolyte membrane 11.

[0041] This process involves applying pressure to the intermediate carbon layer 13X from the gas diffusion layer 14a side while simultaneously applying pressure to the intermediate carbon layer 13X from the catalyst layer 12a side. After heating the intermediate carbon layer 13X, it is cooled to solidify the resin material. As a result, a water-repellent layer 13a is formed between the gas diffusion layer 14a and the catalyst layer 12a. Consequently, the water-repellent layer 13a and the gas diffusion layer 14a are joined together, and the water-repellent layer 13a and the catalyst layer 12a are joined together. This integrates the backsheet 11b, electrolyte membrane 11, catalyst layer 12a, water-repellent layer 13a, and gas diffusion layer 14a.

[0042] Next, in the manufacturing process of step S140 (i.e., the sheet removal process), the back sheet 11b, electrolyte membrane 11, catalyst layer 12a, water-repellent layer 13a, and gas diffusion layer 14a are passed between sheet separators 121a and 121b. At this time, the back sheet 11b is removed from the electrolyte membrane 11 by the sheet separators 121a and 121b. As a result, after the processes of steps 120 and S130 are carried out with the back sheet 11b attached to one side of the electrolyte membrane 11 (i.e., the other side in the lamination direction Ya), the back sheet 11b is removed from the electrolyte membrane 11. Therefore, the electrolyte membrane 11, catalyst layer 12a, water-repellent layer 13a, and gas diffusion layer 14a are formed into a strip-shaped, integrated state.

[0043] Next, in the manufacturing process of step S150, the catalyst layer 12b is laminated on the other side of the electrolyte membrane 11 in the lamination direction Ya. As a result, the catalyst layer 12b, electrolyte membrane 11, catalyst layer 12a, water-repellent layer 13a, and gas diffusion layer 14a are arranged in the order of catalyst layer 12b, electrolyte membrane 11, catalyst layer 12a, water-repellent layer 13a, and gas diffusion layer 14a from the other side to the one side in the lamination direction Ya. Consequently, the catalyst layer 12b, electrolyte membrane 11, catalyst layer 12a, water-repellent layer 13a, and gas diffusion layer 14a are passed between the hot press equipment 130a and 130b.

[0044] As a result, heat is supplied from the hot press equipment 130a and 130b to the catalyst layer 12b, the electrolyte membrane 11, and the catalyst layer 12a. In addition, the hot press equipment 130a and 130b apply pressure from the catalyst layer 12b side to the electrolyte membrane 11, while simultaneously applying pressure from the electrolyte membrane 11 side to the catalyst layer 12b. This causes the catalyst layer 12b and the electrolyte membrane 11 to bond together.

[0045] As a result, the catalyst layer 12b, electrolyte membrane 11, catalyst layer 12a, water-repellent layer 13a, and gas diffusion layer 14a are integrated. The integrated catalyst layer 12b, electrolyte membrane 11, catalyst layer 12a, water-repellent layer 13a, and gas diffusion layer 14a are then cut into a rectangular shape by a cutting machine (not shown). Next, in the manufacturing process of step S160, a solid powder material containing carbon 13d and resin material 13c is blown from the powder ejector 100 onto one surface of the gas diffusion layer 14b. As a result, a film-like intermediate carbon layer 13Y containing carbon 13d and resin material 13c is formed on one surface of the gas diffusion layer 14b.

[0046] Next, in the hot pressing process of step S170, the gas diffusion layer 14b and the intermediate carbon layer 13Y are placed between the hot-pressure bonding members 110c and 110d. In addition, the gas diffusion layer 14b and the intermediate carbon layer 13Y are heated by the hot-pressure bonding members 110c and 110d. As a result, the resin material contained in the intermediate carbon layer 13Y melts. In addition, pressure is applied from the gas diffusion layer 14b side to the intermediate carbon layer 13Y by the hot-pressure bonding member 110c, while pressure is applied from the intermediate carbon layer 13Y side to the gas diffusion layer 14b by the hot-pressure bonding member 110d.

[0047] Next, in the press cooling process of step S180, the gas diffusion layer 14b and the intermediate carbon layer 13Y are placed between the cooling press members 120c and 120d. At this time, the cooling press members 120c and 120d cool the gas diffusion layer 14b and the intermediate carbon layer 13Y while maintaining pressure from the gas diffusion layer 14b side to the intermediate carbon layer 13Y side.

[0048] Therefore, the cooling press members 120c and 120d cool the intermediate carbon layer 13Y so that its temperature is lower than the melting point of the resin material constituting the intermediate carbon layer 13Y. As a result, the resin material contained in the intermediate carbon layer 13Y solidifies. In addition, the cooling press member 120c forms the water-repellent layer 13b which is bonded to the upper surface of the gas diffusion layer 14b.

[0049] Next, in the manufacturing process of step S190, the gas diffusion layer 14b and the water-repellent layer 13b are stacked on the other side of the stacking direction Ya relative to the catalyst layer 12b, electrolyte membrane 11, catalyst layer 12a, water-repellent layer 13a, and gas diffusion layer 14a. This completes the fuel cell cell 10 in which the gas diffusion layer 14a, water-repellent layer 13a, catalyst layer 12a, electrolyte membrane 11, catalyst layer 12b, water-repellent layer 13b, and gas diffusion layer 14b are arranged in that order from one side to the other in the stacking direction Ya.

[0050] Next, the manufacturing method for the intermediate carbon layer 13g of the fuel cell cell 10, which is proportional to the intermediate carbon layer 13g, will be explained with reference to Figure 10. First, an ink solution 13f, in which carbon 13d and resin material 13c are dissolved in solution 13e, is applied to the upper surface of the gas diffusion layer 14a to form a wet intermediate carbon layer 13g on the upper side of the ink solution 13f. After that, a catalyst layer 12a is laminated on the upper side of this formed wet intermediate carbon layer 13g.

[0051] As a result, by drying the ink liquid 13f, a fuel cell cell 10 is completed in which an intermediate carbon layer 13g is placed between the gas diffusion layer 14a and the catalyst layer 12a. However, in the manufacturing process of the intermediate carbon layer 13g, the ink liquid 13f is applied to the gas diffusion layer 14a to form the intermediate carbon layer 13g. Therefore, as shown in Figure 11, the ink liquid 13f permeates the gas diffusion layer 14a by capillary action.

[0052] Here, the Olsson-Pihl equation for determining the penetration depth l of the ink liquid 13f that permeates the gas diffusion layer 14a is shown in equation 1 below. r is the pore size of the porous material constituting the gas diffusion layer 14a, γ is the surface tension of the ink liquid, θ is the contact angle of the ink liquid (i.e., paste) with respect to the gas diffusion layer 14a (i.e., the water-repellent treated substrate), and η is the viscosity of the ink liquid. Pr is the discharge pressure of the ink liquid discharged onto the gas diffusion layer 14a when coating the gas diffusion layer 14a. t is the coating time for coating the gas diffusion layer 14a with the ink liquid.

[0053]

number

[0054] In this embodiment, on one side of the carbon 13d in the stacking direction Ya, as shown in Figures 1 and 12, a plurality of air passages 16a through which air flows are provided, as indicated by arrow Ka in Figure 12 and arrows Ka1 to Ka8 in Figure 13. As shown in Figures 12 and 13, a throttling section 16s is provided in the plurality of air passages 16a to increase the flow velocity of the airflow and supply air from the plurality of air passages 16a to the entire gas diffusion layer 14a. Therefore, a portion of the airflow flowing through the air passages 16a bypasses the throttling section 16s, as indicated by arrows Ka2, Ka3, Ka6, and Ka7 in Figure 13, passes through a portion of the gas diffusion layer 14a, and then flows back into the air passages 16a.

[0055] However, as described above, if carbon and resin materials remain in the gas diffusion layer 14a, these materials will clog the pores inside the gas diffusion layer 14a. As a result, as indicated by arrow Ka2 in Figure 14, the airflow that bypasses the throttling section 16s is prevented from passing through the gas diffusion layer 14a by the carbon and resin materials. Consequently, the flow velocity of the airflow through the multiple air passages 16a decreases. Therefore, the supply of air from the multiple air passages 16a to the entire gas diffusion layer 14a is suppressed.

[0056] On the other hand, even when a carbon intermediate layer is formed between the gas diffusion layer 14b and the catalyst layer 12b using an ink liquid, carbon and a resin material remain in the gas diffusion layer 14b, resulting in a decrease in the air permeability of the gas diffusion layer 14b. Therefore, the carbon and resin material in the gas diffusion layer 14b reduce the flow rate of hydrogen gas in the plurality of hydrogen flow paths 16b. For this reason, the supply of hydrogen gas from the plurality of hydrogen flow paths 16b to the entire gas diffusion layer 14b is suppressed.

[0057] In contrast, in the present embodiment, no ink liquid is used when forming the water-repellent layers 13a and 13b. As a result, the ink liquid does not penetrate into the gas diffusion layers 14a and 14b. Therefore, the remaining of carbon and resin material in the gas diffusion layers 14a and 14b is suppressed. Thus, as shown in FIGS. 15(a) and 15(b), in the fuel cell 10 of the present embodiment, the in-plane air permeability of the gas diffusion layers 14a and 14b can be significantly improved compared to the fuel cell of Patent Document 1. In FIG. 15, (a) shows the in-plane air permeability [10 3 m 3 / (Pa·sec)] of the gas diffusion layer of the fuel cell of Patent Document 1, and (b) shows the in-plane air permeability [10 3 m 3 / (Pa·sec)] of the gas diffusion layers 14a and 14b of the fuel cell 10 of the present embodiment.

[0058] According to the present embodiment described above, the manufacturing method of the fuel cell 10 includes a preparation step S100 of preparing the electrolyte membrane 11, the gas diffusion layer 14a, and the catalyst layer 12a formed in a film shape. The gas diffusion layer 14a is formed in a film shape that spreads in the plane direction Yb intersecting the thickness direction of the electrolyte membrane 11 and diffuses air. The catalyst layer 12a is formed in a film shape along the electrolyte membrane 11 on one side in the stacking direction Ya with respect to the electrolyte membrane 11, and is joined to the electrolyte membrane 11 to form a joined body 11A together with the electrolyte membrane 11. In the catalyst layer 12a, oxygen gas, protons, and electrons contained in the air supplied from the gas diffusion layer 14a react to generate water.

[0059] The manufacturing method for the fuel cell cell 10 includes a hot-pressure bonding step S120 in which heat is applied to the intermediate carbon layer 13X to melt the resin material, with the intermediate carbon layer 13X placed between the gas diffusion layer 14a and the catalyst layer 12a. The intermediate carbon layer 13X is made of a solid material that is formed in powder form and contains carbon and resin material. In the hot-pressure bonding step S120, heat is applied to the intermediate carbon layer 13X to melt the resin material while applying pressure to the intermediate carbon layer 13X from the gas diffusion layer 14a side and from the joint body 11A side.

[0060] The manufacturing method for the fuel cell cell 10 includes a cooling step in step S130. This cooling step cools the intermediate carbon layer 13X after the hot-pressure bonding step while maintaining pressure applied to the intermediate carbon layer 13X from the catalyst layer 12a side while simultaneously applying pressure to the intermediate carbon layer 13X from the gas diffusion layer 14a side. In other words, in steps S120 and S130, heating and cooling of the intermediate carbon layer 13X are performed while maintaining pressure applied to the intermediate carbon layer 13X from the catalyst layer 12a side while simultaneously applying pressure to the intermediate carbon layer 13X from the gas diffusion layer 14a side.

[0061] This process solidifies the resin material while bonding the gas diffusion layer 14a and the water-repellent layer 13a, and also bonding the water-repellent layer 13a to the catalyst layer 12a. Therefore, since no ink liquid is used in the process of forming the water-repellent layer 13a, it is possible to prevent carbon and resin material from remaining inside the gas diffusion layer 14a. Thus, the air permeability of the gas diffusion layer 14a can be improved. For this reason, in the fuel cell cell 10 of this embodiment, air can be supplied well throughout the entire gas diffusion layer 14a from multiple air passages 16a.

[0062] In this embodiment, similar to the water-repellent layer 13a, the water-repellent layer 13b is formed using the intermediate carbon layer 13Y without using an ink solution, as described above. This prevents carbon and resin material from remaining in the gas diffusion layer 14b. Therefore, the air permeability of the gas diffusion layer 14b can be improved. As a result, hydrogen gas can be supplied effectively from the multiple hydrogen channels 16b throughout the entire gas diffusion layer 14b.

[0063] Furthermore, the manufacturing process for the fuel cell cell described in Patent Document 1 requires the production of an ink solution, which inevitably necessitates a solvent. This necessitates prior preparation, such as the time required for preparing the ink solution using the solvent. Because the catalyst layer is bonded to the porous gas diffusion layer using the ink solution, the ink solution seeps into the gas diffusion layer. Additionally, drying the solvent requires several hours if done naturally, or a long time even if forced drying equipment such as hot air drying is used. Moreover, a separate process is required to bond the gas diffusion layer and the catalyst layer, which adds to the time and equipment costs.

[0064] On the other hand, in this embodiment, there is no need to manufacture an ink solution like in the fuel cell cell described in Patent Document 1, and only powdered carbon and resin material are applied to the gas diffusion layers 14a and 14b by electrostatic coating. Therefore, there is no ink solution seepage, and the ink solution manufacturing process and drying process are unnecessary. Furthermore, the manufacturing process in steps S120 and S130 ensures sufficient bonding strength between the interface of the catalyst layer 12a and the interface of the water-repellent layer 13a, the strength of the water-repellent layer 13a itself, and the bonding strength between the interface of the water-repellent layer 13a and the interface of the gas diffusion layer. Therefore, a significant reduction in manufacturing time (i.e., man-hours) and simplification of manufacturing equipment are possible.

[0065] For example, as shown in Figures 16(a) and 16(b), the manufacturing time of the fuel cell cell 10 in this embodiment is significantly shorter than the manufacturing time of the fuel cell cell in Patent Document 1. Figure 16(a) shows the manufacturing time of the fuel cell cell in Patent Document 1, and Figure 16(b) shows the manufacturing time of the fuel cell cell 10 in this embodiment. Figures 16(a) and 16(b) show an example where the manufacturing time of the fuel cell cell 10 in this embodiment is about one-sixth of the manufacturing time of the fuel cell cell in Patent Document 1.

[0066] Figures 17(a)(b) and 18 show the relationship between temperature and bonding strength when the pressure is released after the hot pressing step S120 in the manufacturing process for producing the water-repellent layers 13a and 13b of this embodiment. Here, bonding strength refers to the bonding strength between the interface of the catalyst layer 12a and the interface of the water-repellent layer 13a, the strength of the water-repellent layer 13a itself, and the bonding strength between the interface of the water-repellent layer 13a and the interface of the gas diffusion layer 14a.

[0067] Figure 17(a) shows the bonding strength when the surface pressure is released immediately after thermal bonding of the electrolyte membrane 11, catalyst layer 12a, intermediate carbon layer 13X, and gas diffusion layer 14a in step S120, as shown in Figure 19, under conditions of 3 MPa and a pressing time of 5 minutes. 3 MPa is the pressure applied to the electrolyte membrane 11, catalyst layer 12a, intermediate carbon layer 13X, and gas diffusion layer 14a, and the pressing time of 5 minutes is the time for which pressure is applied to the electrolyte membrane 11, catalyst layer 12a, intermediate carbon layer 13X, and gas diffusion layer 14a.

[0068] Figure 17(b) shows the bond strength when the surface pressure is maintained after thermal bonding of the electrolyte membrane 11, catalyst layer 12a, intermediate carbon layer 13X, and gas diffusion layer 14a in step S120 under conditions of 140°C, 3 MPa, and a press time of 5 minutes. Surface pressure refers to the pressure applied from the catalyst layer 12a to the intermediate carbon layer 13X and the pressure applied from the gas diffusion layer 14a to the intermediate carbon layer 13X. As can be seen from the graphs in Figures 17(a) and 17(b), if the surface pressure is released immediately after thermal bonding, the bond strength cannot meet the standard value.

[0069] Furthermore, it was found that the standard value for bonding strength is met if the pressure (i.e., surface pressure) applied to the intermediate carbon layer 13X is released when the temperature of the intermediate carbon layer 13X is 80°C or lower. In other words, it was found that the desired bonding strength can be secured by maintaining the surface pressure until the temperature of the intermediate carbon layer 13X (i.e., bonding temperature) falls from 140°C to 80°C or lower. In contrast, in this embodiment, by maintaining the application of pressure (i.e., surface pressure) to the intermediate carbon layer 13X in step S130 until the bonding temperature falls from 140°C to 80°C or lower, a bonding strength above the standard value can be secured.

[0070] Therefore, the electrolyte membrane 11, catalyst layer 12a, intermediate carbon layer 13X, and gas diffusion layer 14a are integrated and have sufficient strength (i.e., rigidity). As a result, after the process in step S130, in step S140, the back sheet 11b can be easily peeled off and removed from the electrolyte membrane 11. In this embodiment configured in this way, the following effects (a), (b), and (c) can be obtained.

[0071] (a) The cooling step in step S130 cools the intermediate carbon layer 13X until the temperature of the resin material contained in the intermediate carbon layer 13X falls below its melting point. This allows the intermediate carbon layer 13X to solidify sufficiently and form a good water-repellent layer 13a. (b) The resin material contained in the intermediate carbon layer 13X has a melting point lower than that of the electrolyte membrane 11. In the thermal bonding process of step S120, the temperature of the electrolyte membrane 11 can be made lower than that of the electrolyte membrane 11. The thermal bonding process of step S120 can prevent adverse effects on the electrolyte membrane 11.

[0072] (c) The heat resistance temperature of the ionomer contained in the electrolyte membrane 11 is defined as the first heat resistance temperature, and the heat resistance temperature of the ionomer contained in the catalyst layer 12a is defined as the second heat resistance temperature. In the thermal bonding step S120, the intermediate carbon layer 13X is heated so that the temperature of the electrolyte membrane 11 falls below the first heat resistance temperature and the temperature of the catalyst layer 12a falls below the second heat resistance temperature. Therefore, the thermal bonding step S120 prevents damage to the ionomer of the electrolyte membrane 11 and the ionomer of the catalyst layer 12a, respectively.

[0073] (Second Embodiment) In the first embodiment described above, an example was described in which, in the manufacturing process of the fuel cell cell 10, the gas diffusion layer 14b and the water-repellent layer 13b were stacked on the other side of the stacking direction Ya relative to the catalyst layer 12b, so that the catalyst layer 12b and the water-repellent layer 13b were not joined. However, instead, this second embodiment, in which the gas diffusion layer 14b and the water-repellent layer 13b are stacked on the other side of the stacking direction Ya relative to the catalyst layer 12b, and the catalyst layer 12b and the water-repellent layer 13b are joined, will be described with reference to Figures 20 and 21.

[0074] Figure 20 is a flowchart showing the manufacturing process of the fuel cell 10 of this embodiment. Figure 21 is a schematic diagram to aid in explaining the manufacturing process in Figure 20. In Figures 20 and 21, the same reference numerals as in Figures 8 and 9 indicate the same steps, and their explanations are omitted. The manufacturing process of the fuel cell 10 of this embodiment differs from that of the fuel cell 10 of the first embodiment mainly in the manufacturing process of the water-repellent layer 13b. The manufacturing process of the water-repellent layer 13b in the manufacturing process of the fuel cell 10 of this embodiment will be described below.

[0075] First, the manufacturing process from steps S100 to S150 is carried out, similar to the first embodiment described above. As a result, the catalyst layer 12b, electrolyte membrane 11, catalyst layer 12a, water-repellent layer 13a, and gas diffusion layer 14a are integrated together with the catalyst layer 12b and electrolyte membrane 11 bonded together. Next, the manufacturing process of step S160 is carried out in the same manner as in the first embodiment described above. This forms an intermediate carbon layer 13Y on one surface of the gas diffusion layer 14b.

[0076] Next, in the hot pressing process of step S200, the gas diffusion layer 14b and the intermediate carbon layer 13Y are laminated on the catalyst layer 12b such that the intermediate carbon layer 13Y is positioned between the gas diffusion layer 14b and the catalyst layer 12b. As a result, the gas diffusion layer 14a, the water-repellent layer 13a, the catalyst layer 12a, the electrolyte membrane 11, the catalyst layer 12b, the intermediate carbon layer 13Y, and the gas diffusion layer 14b are laminated in the lamination direction Ya.

[0077] Accordingly, the hot-pressure bonding member 140a applies pressure from one side in the lamination direction Ya to the gas diffusion layer 14a, water-repellent layer 13a, catalyst layer 12a, electrolyte membrane 11, catalyst layer 12b, intermediate carbon layer 13Y, and gas diffusion layer 14b. The hot-pressure bonding member 140b applies pressure from the other side in the lamination direction Ya to the gas diffusion layer 14a, water-repellent layer 13a, catalyst layer 12a, electrolyte membrane 11, catalyst layer 12b, intermediate carbon layer 13Y, and gas diffusion layer 14b. In this state, the hot-pressure bonding members 140a and 140b transfer heat to the gas diffusion layer 14a, water-repellent layer 13a, catalyst layer 12a, electrolyte membrane 11, catalyst layer 12b, intermediate carbon layer 13Y, and gas diffusion layer 14b.

[0078] This process applies pressure to the intermediate carbon layer 13Y from both the catalyst layer 12b and the gas diffusion layer 14b, thereby heating the intermediate carbon layer 13Y and melting the resin material. Here, the heat resistance temperature of the ionomer contained in the electrolyte membrane 11 is defined as the first heat resistance temperature, and the heat resistance temperature of the ionomer contained in the catalyst layer 12a is defined as the second heat resistance temperature. In this embodiment, the intermediate carbon layer 13Y is heated by the thermo-pressure bonding members 110a and 110b so that the temperature of the electrolyte membrane 11 falls below the first heat resistance temperature and the temperature of the catalyst layer 12a falls below the second heat resistance temperature.

[0079] Next, in the press cooling step of step S210, the cooling press member 150a maintains applying pressure from one side in the lamination direction Ya to the gas diffusion layer 14a, water-repellent layer 13a, catalyst layer 12a, electrolyte membrane 11, catalyst layer 12b, intermediate carbon layer 13Y, and gas diffusion layer 14b. At this time, the cooling press member 150b maintains applying pressure from the other side in the lamination direction Ya to the gas diffusion layer 14a, water-repellent layer 13a, catalyst layer 12a, electrolyte membrane 11, catalyst layer 12b, intermediate carbon layer 13Y, and gas diffusion layer 14b.

[0080] In addition, the cooling press members 150a and 150b cool the gas diffusion layer 14a, the water-repellent layer 13a, the catalyst layer 12a, the electrolyte membrane 11, the catalyst layer 12b, the intermediate carbon layer 13Y, and the gas diffusion layer 14b. Furthermore, in this embodiment, the cooling press members 150a and 150b cool the intermediate carbon layer 13Y so that the resin material constituting the intermediate carbon layer 13Y is lower than the melting point of the resin material.

[0081] This process cools the intermediate carbon layer 13Y and solidifies the resin material while maintaining pressure applied from the catalyst layer 12b to the intermediate carbon layer 13Y and from the gas diffusion layer 14b to the intermediate carbon layer 13Y. Consequently, a water-repellent layer 13b is formed between the catalyst layer 12b and the gas diffusion layer 14b. As a result, the water-repellent layer 13b and the gas diffusion layer 14b are joined together, and the water-repellent layer 13b and the catalyst layer 12b are joined together. This integrates the gas diffusion layer 14a, water-repellent layer 13a, catalyst layer 12a, electrolyte membrane 11, catalyst layer 12b, water-repellent layer 13b, and gas diffusion layer 14b, completing the manufacturing of the fuel cell cell 10.

[0082] In the manufacturing process of the fuel cell cell 10 of this embodiment described above, the catalyst layer 12b, electrolyte membrane 11, catalyst layer 12a, water-repellent layer 13a, and gas diffusion layer 14a are integrated, similar to the first embodiment described above. Subsequently, the gas diffusion layer 14b and intermediate carbon layer 13Y are laminated onto the catalyst layer 12b, electrolyte membrane 11, catalyst layer 12a, water-repellent layer 13a, and gas diffusion layer 14a. In the next manufacturing step, while applying pressure to the intermediate carbon layer 13Y from the catalyst layer 12b side and applying pressure to the intermediate carbon layer 13Y from the gas diffusion layer 14b side, heat is applied to the intermediate carbon layer 13Y to melt the resin material.

[0083] In the next manufacturing step, while maintaining pressure applied from the catalyst layer 12b to the intermediate carbon layer 13Y and from the gas diffusion layer 14b to the intermediate carbon layer 13Y, the intermediate carbon layer 13Y is cooled to solidify the resin material. This forms a water-repellent layer 13b between the catalyst layer 12b and the gas diffusion layer 14b. Consequently, the water-repellent layer 13b and the gas diffusion layer 14b are joined together, and the water-repellent layer 13b and the catalyst layer 12b are joined together. This completes the manufacturing of the fuel cell cell 10.

[0084] Therefore, since no ink solution is used in the process of forming the water-repellent layer 13b, it is possible to suppress the residue of carbon and resin materials in the gas diffusion layer 14b. As a result, the air permeability of the gas diffusion layer 14b can be significantly improved. Consequently, the strength of the water-repellent layer 13b itself, as well as the bonding strength between the water-repellent layer 13b and the gas diffusion layer 14b, can be improved.

[0085] (Other embodiments) (1) In the first and second embodiments described above, an example was given in which the assembled body 11A was constructed using a catalyst layer 12a and an electrolyte membrane 11. However, instead, the assembled body 11A may be constructed using a catalyst layer 12b and an electrolyte membrane 11. In this case, in the first and second embodiments described above, after forming the gas diffusion layer 14b, water-repellent layer 13b, catalyst layer 12b, and electrolyte membrane 11, the catalyst layer 12b, water-repellent layer 13b, and gas diffusion layer 14b are laminated onto the gas diffusion layer 14b, water-repellent layer 13b, catalyst layer 12b, and electrolyte membrane 11.

[0086] (2) In the first and second embodiments described above, examples were given in which powdered carbon was used as the intermediate carbon layers 13X and 13Y. However, the intermediate carbon layers 13X and 13Y may be constructed using granular carbon. Also, examples were given in which powdered oil material was used as the intermediate carbon layers 13X and 13Y. However, the intermediate carbon layers 13X and 13Y may be constructed using granular oil material.

[0087] (3) In the first and second embodiments described above, an example was given in which the integrated catalyst layer 12b, electrolyte membrane 11, catalyst layer 12a, water-repellent layer 13a, and gas diffusion layer 14a were cut after the manufacturing process of step S150. However, the step of cutting the integrated catalyst layer 12b, electrolyte membrane 11, catalyst layer 12a, water-repellent layer 13a, and gas diffusion layer 14a may be omitted instead. (4) In the first embodiment described above, a cooling step was described in which the gas diffusion layer 14b and the intermediate carbon layer 13Y are cooled while pressure is applied from the gas diffusion layer 14b side to the intermediate carbon layer 13Y side. However, in the first embodiment described above, the cooling step may be omitted instead.

[0088] (5) This disclosure is not limited to the embodiments described above, and can be modified as appropriate within the scope of the claims. Furthermore, the embodiments described above are not unrelated to each other and can be combined as appropriate, except in cases where the combination is clearly impossible. In addition, it goes without saying that the elements constituting the embodiments are not necessarily essential, except in cases where they are explicitly stated to be particularly essential or where they are clearly considered essential in principle. Furthermore, in the embodiments described above, when numerical values ​​such as the number, numerical values, quantities, or ranges of the components of the embodiments are mentioned, they are not limited to those specific numbers, except in cases where they are explicitly stated to be particularly essential or where they are clearly limited to a specific number in principle. Furthermore, in the embodiments described above, when the shape, positional relationship, etc., of the components are mentioned, they are not limited to those shapes, positional relationships, etc., except in cases where they are explicitly stated to be particularly essential or where they are clearly limited to a specific shape, positional relationship, etc., in principle. [Explanation of symbols]

[0089] 10 fuel cell cells 11 Electrolyte membrane 12a Catalyst layer 12b Catalyst layer 13a Water-repellent layer 13b Water-repellent layer 14a Gas diffusion layer 14b Gas diffusion layer 15a Separator 15b Separator 16a Airflow channel 16b Hydrogen channel

Claims

1. An electrolyte membrane (11) formed in a film-like manner, and gas diffusion layers (14a, 14b) formed in a film-like manner that extend in an intersecting direction (Yb) intersecting the thickness direction (Ya) of the electrolyte membrane, which diffuse gas, Preparation step (S100) to prepare catalyst layers (12a, 12b) which are arranged between the electrolyte membrane and the gas diffusion layer in the thickness direction, formed in a film shape along the electrolyte membrane, bonded to the electrolyte membrane to form a bonded body (11A) together with the electrolyte membrane, and generate a reaction related to power generation using the gas diffused by the gas diffusion layer, A hot-pressure bonding step (S120) is performed in which an intermediate carbon layer (13X, 13Y) made of a solid material containing carbon and resin material and formed in granular or powder form is placed between the gas diffusion layer and the catalyst layer, and while pressure is applied to the intermediate carbon layer from the gas diffusion layer side and pressure is applied to the intermediate carbon layer from the catalyst layer side, heat is applied to the intermediate carbon layer to melt the resin material, After the hot-pressure bonding step, a cooling step (S130) is performed in which, while maintaining pressure applied from the gas diffusion layer side to the intermediate carbon layer and pressure applied from the catalyst layer side to the intermediate carbon layer, the intermediate carbon layer is cooled to solidify the resin material, thereby bonding the gas diffusion layer and the intermediate carbon layer, and bonding the intermediate carbon layer and the catalyst layer. A method for manufacturing a fuel cell, including the fuel cell itself.

2. A method for manufacturing a fuel cell according to claim 1, comprising a sheet removal step (S140) in which, after performing the hot-pressure bonding step and the cooling step with a back sheet (11b) for maintaining the shape of the electrolyte membrane attached to the other side of the electrolyte membrane in the thickness direction, the back sheet is removed from the electrolyte membrane.

3. The method for manufacturing a fuel cell according to claim 1, wherein the cooling step involves cooling the intermediate carbon layer until the temperature of the resin material falls below its melting point.

4. The method for manufacturing a fuel cell according to claim 1, wherein the resin material has a melting point lower than the melting point of the electrolyte membrane.

5. When the heat resistance temperature of the ionomer contained in the electrolyte membrane is defined as the first heat resistance temperature, and the heat resistance temperature of the ionomer contained in the catalyst layer is defined as the second heat resistance temperature, The method for manufacturing a fuel cell according to claim 1, wherein in the hot-pressure bonding step, the intermediate carbon layer is heated so that the temperature of the electrolyte membrane falls below the first heat resistance temperature and the temperature of the catalyst layer falls below the second heat resistance temperature.

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