JP6863260B2 - Fuel cell manufacturing method - Google Patents

Description

The present invention relates to a method for manufacturing a fuel cell.

A fuel cell in which a plurality of stacked single cells are bonded with an adhesive is known. As a method for manufacturing such a fuel cell, in order to shorten the curing time of the adhesive, there is a method of curing the adhesive by flowing a high-temperature fluid through the flow path inside the fuel cell and heating the fuel cell from the inside. It is known (for example, Patent Document 1).

Japanese Unexamined Patent Publication No. 2006-134731

However, in the method described in Patent Document 1, there is a possibility that the high-temperature fluid may flow out of the flow path from the flow path to the outside of the fuel cell between the time when the high-temperature fluid is started to flow in the flow path inside the fuel cell and the time when the adhesive is cured. As a result, there is a risk that the adhesive will not adhere well.

The present invention has been made in view of the above problems, and an object of the present invention is to perform good adhesion with an adhesive.

The present invention has an anode separator and a cathode having a first through hole forming a manifold, a protrusion formed on at least one of a peripheral portion of the first through hole and a peripheral portion of a region corresponding to a power generation region, respectively. The separators were joined so that the protrusions of each other protruded to the opposite side and the space formed between the protrusions of each other communicated with the flow path for flowing the fluid introduced into the manifold into the power generation region. The protrusion is heated to a plurality of insulating frames having a step of preparing a plurality of separator assemblies and a second through hole which is arranged on the outer peripheral edge of the plurality of membrane electrode assemblies and has a second through hole forming the manifold. The plurality of membrane electrode assemblies and the plurality of insulating frames and the plurality of separator assemblies are alternately laminated to form a laminate so as to be in contact with each other via an adhesive containing a curable resin or a thermoplastic resin. The step, the step of pressing the laminate in the stacking direction so that the protrusion is deformed, and the curing temperature of the thermocurable resin or the melting point of the thermoplastic resin in the flow path with the protrusion deformed. It is a method of manufacturing a fuel cell including the above-mentioned step of flowing a high-temperature fluid.

According to the present invention, adhesion with an adhesive can be performed satisfactorily.

1A and 1B are plan views showing a method for manufacturing a fuel cell according to the first embodiment. 2 (a) to 2 (e) are cross-sectional views (No. 1) showing a method for manufacturing a fuel cell according to the first embodiment. 3 (a) and 3 (b) are cross-sectional views (No. 2) showing a method for manufacturing a fuel cell according to the first embodiment. 4 (a) and 4 (b) are cross-sectional views (No. 3) showing a method for manufacturing a fuel cell according to the first embodiment. FIG. 5 is a cross-sectional view of a separator assembly having protrusions having a different shape. FIG. 6 is a diagram showing a method for manufacturing a fuel cell according to the second embodiment.

Hereinafter, examples of the present invention will be described with reference to the drawings.

1A and 1B are plan views showing a method for manufacturing a fuel cell according to the first embodiment. 2 (a) to 4 (b) are cross-sectional views showing a method of manufacturing a fuel cell according to the first embodiment. FIG. 2A is a cross-sectional view taken along the line AA of FIG. 1A. 2 (b) to 2 (e) are cross-sectional views taken between AA and DD in FIG. 1B. 3 (a) and 3 (b) are cross-sectional views of a portion corresponding to the space between AA and BB in FIG. 1 (b). 4 (a) and 4 (b) are cross-sectional views of locations corresponding to the intervals between CC and DD in FIG. 1 (b). The fuel cell described in the embodiment is a polymer electrolyte fuel cell that generates electricity by being supplied with a fuel gas (for example, hydrogen) and an oxidant gas (for example, air) as reaction gases, and a large number of single cells are laminated. It has a stack structure. The fuel cell is installed in, for example, a fuel cell vehicle or an electric vehicle.

As shown in FIGS. 1A and 2A, the anode catalyst layer 14a is formed on the entire surface of one surface of the electrolyte membrane 12, and the outer peripheral edge portion 22 is exposed on the other surface to provide the cathode catalyst layer 14c. Form. The anode catalyst layer 14a and the cathode catalyst layer 14c are formed by, for example, spray-coating the catalyst ink. As a result, a membrane electrode assembly (MEA) 10 is formed. The anode catalyst layer 14a and the cathode catalyst layer 14c may be formed by a transfer method, a die coater method, or the like.

The electrolyte membrane 12 is a solid polymer membrane formed of a fluororesin material or a hydrocarbon resin material having a sulfonic acid group, and has good proton conductivity in a wet state. The anode catalyst layer 14a and the cathode catalyst layer 14c are solid polymers having carbon particles (for example, carbon black) carrying a catalyst (for example, platinum or platinum-cobalt alloy) for advancing an electrochemical reaction and a sulfonic acid group, and are wet. Includes ionomers, which have good proton conductivity in the state.

Next, the anode gas diffusion layer 16a is arranged outside the anode catalyst layer 14a, and the cathode gas diffusion layer 16c is arranged outside the cathode catalyst layer 14c. Then, for example, by thermocompression bonding, the anode gas diffusion layer 16a is bonded to the anode catalyst layer 14a, and the cathode gas diffusion layer 16c is bonded to the cathode catalyst layer 14c. As a result, a membrane electrode gas diffusion layer assembly (MEGA) 20 is formed. The anode gas diffusion layer 16a and the cathode gas diffusion layer 16c are formed of a member having gas permeability and electron conductivity, and are formed of a porous carbon member such as carbon cloth or carbon paper.

Next, a frame-shaped insulating frame 60 provided with an adhesive 74 containing a thermosetting resin or a thermoplastic resin on both main surfaces is arranged on the outer peripheral edge portion 22 of the electrolyte membrane 12 via the adhesive 74. The insulating frame 60 has a melting point higher than the curing temperature or melting point of the adhesive 74. The insulating frame 60 is formed of an elastic resin member such as rubber or an elastomer resin, but may be formed of a non-elastic insulating member. Examples of the adhesive 74 include those containing maleic acid-modified polypropylene or maleic acid-modified polyolefin and an adhesive component. Examples of the adhesive component include acid anhydrides containing maleic anhydride, carboxylic acids containing acrylic acid or methacrylic acid, and alcohols containing vinyl alcohol or ethylhexyl acrylate. Further, the adhesive 74 may be added with a silane coupling agent, an epoxy resin, a urethane resin, or the like.

In Example 1, in FIGS. 1 (a) and 2 (a), the case where the insulating frame 60 is not adhered to the electrolyte membrane 12 is shown as an example, but the insulating frame 60 is, for example, an ultraviolet curable resin. It may be the case where it is adhered to the electrolyte membrane 12 with an adhesive or the like.

The insulating frame 60 is provided with through holes 62 to 72. The through hole 62 constitutes a part of the oxidant gas supply manifold that supplies the oxidant gas to the MEA 10, and the through hole 72 forms a part of the oxidant gas discharge manifold that discharges the oxidant gas supplied to the MEA 10. Configure. The through hole 64 constitutes a part of the refrigerant supply manifold that supplies the refrigerant to the MEA 10, and the through hole 70 constitutes a part of the refrigerant discharge manifold that discharges the refrigerant supplied to the MEA 10. The through hole 68 constitutes a part of the fuel gas supply manifold that supplies the fuel gas to the MEA 10, and the through hole 66 constitutes a part of the fuel gas discharge manifold that discharges the fuel gas supplied to the MEA 10.

As shown in FIGS. 1 (b) and 2 (b) to 2 (e), the anode separator 18a and the cathode separator 18c are joined to form the separator assembly 40. The anode separator 18a and the cathode separator 18c are formed of a member having gas blocking property and electron conductivity, and are formed of, for example, a metal member such as press-molded stainless steel. The anode separator 18a and the cathode separator 18c are joined by, for example, laser welding.

Through holes 42 to 52 are provided in the anode separator 18a and the cathode separator 18c. The through hole 42 forms a part of the oxidant gas supply manifold, and the through hole 52 forms a part of the oxidant gas discharge manifold. The through hole 44 forms a part of the refrigerant supply manifold, and the through hole 50 forms a part of the refrigerant discharge manifold. The through hole 48 forms a part of the fuel gas supply manifold, and the through hole 46 forms a part of the fuel gas discharge manifold.

The peripheral portions of the through holes 42 to 52 of the anode separator 18a and the cathode separator 18c and the peripheral portion of the region 24 corresponding to the power generation region are protrusions 54 and 56. In FIG. 1B, the portion where the protrusions 54 and 56 are formed is shown by a broken line. The anode separator 18a and the cathode separator 18c are joined so that the protrusions 54 and 56 project to the opposite side and spaces 58a to 58d are formed between them. The protrusions 54 and 56 extend around the through holes 42 to 52 so as to completely surround the through holes 42 to 52. Further, the protrusions 54 and 56 extend the outer peripheral portions of the anode separator 18a and the cathode separator 18c so as to collectively surround the through holes 42, 46, 48, 52, and the region 24. The dotted line connected between each through hole and the region 24 in FIG. 1B is a flow path through which the fluid introduced into each manifold flows into the power generation region or a fluid flowing through the power generation region flows through each manifold. The flow path is shown.

As shown in FIG. 2B, the space 58a communicates with the flow path 26 through which the refrigerant flows between the refrigerant supply manifold formed by the through hole 44 and the refrigerant discharge manifold formed by the through hole 50. .. As shown in FIG. 2C, the space 58b is a flow path through which the oxidant gas flows between the oxidant gas supply manifold formed by the through hole 42 and the oxidant gas discharge manifold formed by the through hole 52. It communicates with 28. The flow path 28 extends through a hole 29 penetrating the cathode separator 18c. As shown in FIG. 2D, the space 58c communicates with the flow path 30 through which the fuel gas flows between the fuel gas supply manifold formed by the through hole 48 and the fuel gas discharge manifold formed by the through hole 46. doing. The flow path 30 extends through a hole 31 penetrating the anode separator 18a. The space 58d is connected to the space 58a and communicates with the flow path 26.

As shown in FIGS. 3A to 4B, the plurality of MEGA 20s and the plurality of insulating frames 60 are arranged so that the protrusions 54 and 56 of the separator assembly 40 come into contact with the insulating frame 60 via the adhesive 74. A plurality of separator assemblies 40 are alternately laminated to form a laminated body 80. As a result, the through holes 62 to 72 provided in the insulating frame 60 and the through holes 42 to 52 provided in the anode separator 18a and the cathode separator 18c communicate with each other, and the oxidant gas supply manifold, the refrigerant supply manifold, and the fuel gas are discharged. A manifold, a fuel gas supply manifold, a refrigerant discharge manifold, and an oxidant gas discharge manifold are formed.

The laminated body 80 is pressed from the laminating direction to deform (for example, elastically deform) the protrusions 54 and 56. Then, while maintaining the deformed state of the protrusions 54 and 56, the high temperature fluid is flowed from the oxidant gas supply or discharge manifold, the refrigerant supply or discharge manifold, and the fuel gas supply or discharge manifold to the flow paths 26 to 30. When the adhesive 74 contains a thermosetting resin, the temperature of the high-temperature fluid is set to a temperature equal to or higher than the curing temperature of the thermosetting resin, and when the adhesive 74 contains a thermoplastic resin, the temperature is set to a temperature equal to or higher than the melting point of the thermoplastic resin. To do. The temperature of the high-temperature fluid is preferably a temperature at which it is difficult to reduce the strength of the electrolyte membrane 12 and the insulating frame 60, for example, preferably 150 ° C. or lower, more preferably 140 ° C. or lower, and 130 ° C. or lower. There are more preferred cases. As the fluid, it is preferable to use a fluid that does not deteriorate the catalyst, and for example, air, nitrogen, hydrogen, water, or Fluorinert (registered trademark) is preferably used.

When the adhesive 74 contains a thermosetting resin, the insulating frame 60 and the protrusions 54 and 56 are adhered to each other by the adhesive 74 by flowing a high-temperature fluid equal to or higher than the curing temperature of the thermosetting resin through the flow paths 26 to 30. Can be made to. That is, the plurality of MEGA 20 and the plurality of separator assemblies 40 can be adhered with the adhesive 74. When the adhesive 74 contains a thermoplastic resin, a high-temperature fluid equal to or higher than the melting point of the thermoplastic resin is flowed through the flow paths 26 to 30, and then the protrusions 54 and 56 remain deformed and are lower than the melting point of the thermoplastic resin. Cool to temperature. The adhesive 74 may be cooled by flowing a low-temperature fluid having a melting point lower than the melting point of the thermoplastic resin in the flow paths 26 to 30. As a result, the insulating frame 60 and the protrusions 54 and 56 can be adhered to each other with the adhesive 74. That is, the plurality of MEGA 20 and the plurality of separator assemblies 40 can be adhered with the adhesive 74. The electrolyte membrane 12 and the insulating frame 60 may be adhered to each other with the adhesive 74 by flowing a high-temperature fluid.

As described above, according to the first embodiment, as shown in FIGS. 1 (b) and 2 (b) to 2 (e), the anode separator 18a having the protrusions 54 and 56 and the cathode separator 18c are joined, respectively. A plurality of separator assemblies 40 are prepared. In the separator assembly 40, the anode separator 18a and the cathode separator 18c are provided so that the protrusions 54 and 56 project to the opposite side and the spaces 58a to 58d between the protrusions 54 and 56 communicate with the flow paths 26 to 30. It is joined. As shown in FIGS. 3A to 4B, the plurality of MEA10s are in contact with the insulating frames 60 arranged on the outer peripheral edges 22 of the plurality of MEA10s so that the protrusions 54 and 56 are in contact with each other via the adhesive 74. The plurality of insulating frames 60 and the plurality of separator assemblies 40 are alternately laminated to form the laminated body 80. Then, the laminated body 80 is pressed in the stacking direction until the protrusions 54 and 56 are deformed, and in the state where the protrusions 54 and 56 are deformed, a high temperature fluid having a curing temperature of the adhesive 74 or higher than the melting point is applied to the flow paths 26 to 30. Shed.

In this way, by pressing the laminated body 80 in the stacking direction to bring the protrusions 54 and 56 into a deformed state (for example, an elastically deformed state), the reaction force of the protrusions 54 and 56 causes a flow path from each manifold. The high temperature fluid flowing in 26 to 30 can be sealed. Therefore, by flowing a high-temperature fluid having a curing temperature of the adhesive 74 or higher than the melting point in the flow paths 26 to 30 in this state, the high-temperature fluid is suppressed from flowing out to the outside of the fuel cell. Therefore, the plurality of MEAs 10 and the plurality of separator assemblies 40 can be satisfactorily adhered to each other by the adhesive 74. The pressure when the high temperature fluid flows through the flow paths 26 to 30 is relatively low. Therefore, even if the anode separator 18a and the cathode separator 18c are not adhered to the insulating frame 60, the high temperature fluid can be sufficiently sealed by the reaction force of the protrusions 54 and 56.

In FIGS. 2 (b) to 2 (e), the case where the protrusions 54 and 56 have one mountain shape is shown as an example, but other shapes may be used. FIG. 5 is a cross-sectional view of a separator assembly having protrusions having a different shape. As shown in FIG. 5, the protrusions 54a and 56a of the separator assembly 40a include a mountain portion 55 located at the center and a mountain portion 57 lower than the mountain portion 55 located on both sides of the mountain portion 55. You may be doing it. The mountain portion 55 is an adhesive portion with the insulating frame 60, and the mountain portion 57 is an elastic portion, so that the adhesive portion and the elastic portion can be separated.

After the plurality of MEGA 20s and the plurality of separator assemblies 40 are adhered with the adhesive 74, the height of the flow path 26 between the refrigerant supply manifold and the refrigerant discharge manifold and the space 58a is the height of the space 58a. It is lower than that. Similarly, the height of the flow path 28 between the oxidant gas supply manifold and the oxidant gas discharge manifold and the space 58b is lower than the height of the space 58b. The height of the flow path 30 between the fuel gas supply manifold and the fuel gas discharge manifold and the space 58c is lower than the height of the space 58c.

FIG. 6 is a diagram showing a method for manufacturing a fuel cell according to the second embodiment. First, the manufacturing process described in Example 1 is carried out to form the laminated body 80. After that, as shown in FIG. 6, the laminated body 80 in a state where the protrusions 54 and 56 are deformed by being pressed in the stacking direction is housed in the container 90. The container 90 is, for example, a constant temperature and constant pressure tank. A high-temperature fluid adjusted to a temperature equal to or higher than the curing temperature or melting point of the adhesive 74 is sealed in the container 90. The pressure in the container 90 is adjusted to be higher than the atmospheric pressure. For example, the pressure in the flow paths 26 to 30 when the high temperature fluid flows through the flow paths 26 to 30 of the laminated body 80 is the same as the pressure in the flow paths 26 to 30. (For example, the pressure difference is adjusted to 5 kPa or less).

The pressure in the container 90 is increased, and the high-temperature fluid sealed in the container 90 is flowed from the manifold of the laminated body 80 in the state where the protrusions 54 and 56 are deformed to the flow paths 26 to 30. As a result, the plurality of insulating frames 60 constituting the laminated body 80 and the plurality of separator assemblies 40 are adhered with the adhesive 74.

When the high temperature fluid flows through the flow paths 26 to 30, the pressure in the flow paths 26 to 30 tends to be higher than the atmospheric pressure. In this case, in the first embodiment, the pressure difference between the pressure inside the flow paths 26 to 30 and the atmospheric pressure outside the laminate 80 becomes large, so that the high-temperature fluid is not sufficiently sealed at the bonded portion and the fuel cell is used. There is a risk of leakage to the outside. On the other hand, in the second embodiment, the laminated body 80 is housed in the container 90, and the pressure in the container 90 is adjusted to be about the same as the pressure in the flow paths 26 to 30 when the high temperature fluid flows. A high temperature fluid is flowing through the flow paths 26 to 30. As a result, the pressure difference between the pressure inside the flow paths 26 to 30 and the pressure outside the laminate 80 becomes small, and it is possible to prevent the high-temperature fluid from flowing out to the outside of the fuel cell.

Further, according to the second embodiment, since the laminated body 80 is housed in the container 90 in which the high temperature fluid is sealed, it is possible to effectively raise the temperature of the entire laminated body 80 uniformly.

Further, as shown in FIG. 6, the pressure regulating valve 94 is arranged in the pipe 92 connected to the manifold in which the high temperature fluid of the laminated body 80 is discharged, and the pressure in the flow paths 26 to 30 and the container when the high temperature fluid flows. The pressure in the flow paths 26 to 30 may be adjusted by the pressure regulating valve 94 so that the pressure in the 90 is about the same.

In the second embodiment, not only in the case where the pressure in the container 90 is increased and the high-temperature fluid sealed in the container 90 flows through the flow paths 26 to 30, a suction pump is arranged in the pipe 92, and the flow paths 26 to 26 are operated by the suction pump. High temperature fluid may be sucked and exhausted through 30.

In the first and second embodiments, the manifold into which the high-temperature fluid is introduced may be a supply manifold or a discharge manifold. Further, in Examples 1 and 2, the protrusions 54 and 56 of the anode separator 18a and the cathode separator 18c are formed in the peripheral portion of the through holes 42 to 52 and the peripheral portion of the region 24 corresponding to the power generation region, respectively. It was formed, but not limited to this. It may be formed in at least one of the peripheral portion of the through holes 42 to 52 and the peripheral portion of the region 24 corresponding to the power generation region.

In Examples 1 and 2, the temperature at which the high-temperature fluid flowing through the flow paths 26 to 30 is discharged from the laminate 80 is measured, and the temperature of the adhesive 74 is estimated from this temperature. The start and / or end of adhesion by the adhesive 74 may be determined. Further, the pressure of the high-temperature fluid when discharged from the laminated body 80 may be measured, and it may be determined from this pressure value whether or not the adhesion by the adhesive 74 is normally performed. Further, after the production of the fuel cell is completed, a fluid may be flowed through the flow paths 26 to 30 to check whether the adhesion by the adhesive 74 is normally performed and whether there is a leak.

Although the examples of the present invention have been described in detail above, the present invention is not limited to such specific examples, and various modifications and modifications are made within the scope of the gist of the present invention described in the claims. It can be changed.

10 Membrane electrode assembly 12 Electrolyte membrane 14a Anode catalyst layer 14c Cathode catalyst layer 16a Anode gas diffusion layer 16c Cathode gas diffusion layer 18a Anode separator 18c Cathode separator 20 Membrane electrode gas diffusion layer assembly 22 Outer peripheral edge 24 region 26 to 30 flow Roads 29, 31 Holes 40, 40a Separator assembly 42-52 Through holes 54, 54a, 56, 56a Protrusions 55, 57 Mountains 58a-58d Space 60 Insulation frame 62-72 Through holes 74 Adhesive 80 Laminated body 90 Container 92 Piping 94 Pressure regulating valve

Claims (1)

An anode separator and a cathode separator having a first through hole forming a manifold and a protrusion formed on at least one of a portion surrounding the first through hole and a portion surrounding a region corresponding to a power generation region, respectively, A plurality of separator sets in which the protrusions of the above project to the opposite side and a space formed between the protrusions of the above is joined so as to communicate with a flow path for flowing a fluid introduced into the manifold into the power generation region. The process of preparing the solid and
An adhesive containing a thermosetting resin or a thermoplastic resin in a plurality of insulating frames having a frame-like shape and second through holes forming the manifold and having the protrusions arranged on the outer peripheral edge of the plurality of membrane electrode assemblies. A step of alternately laminating the plurality of membrane electrode assemblies, the plurality of insulating frames, and the plurality of separator assemblies to form a laminate so as to be in contact with each other.
A step of pressing the laminated body in the laminating direction so that the protruding portion is deformed, and
A method for manufacturing a fuel cell, comprising a step of flowing a high-temperature fluid having a curing temperature of the thermosetting resin or a melting point of the thermoplastic resin or higher in the flow path in a deformed state of the protrusion.

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