Adhesive application system

Abstract

To make an adhesive less likely to spread beyond a desired application area when bonding a gas diffusion layer to an intermediate layer in the manufacturing stage of a fuel cell.SOLUTION: Using an adhesive coating system, an adhesive is applied on an intermediate layer in a manufacturing step of a fuel cell with the intermediate layer and gas diffusion layers on both sides of the intermediate layer. The adhesive application system has an application unit, a robot arm, and a controller. The application unit applies an adhesive when a valve is opened. The robot arm can move the application unit. The controller controls the valve and the robot arm. The controller linearly applies the adhesive to the intermediate layer from the application start point, by opening the valve before the application unit becomes located immediately on the application start point while moving the application unit by the robot arm.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a system for applying an adhesive to a member constituting a fuel cell.

Background Art

[0002] Some fuel cells include, in order from one side, a gas diffusion layer on the anode side, an intermediate layer, and a gas diffusion layer on the cathode side. When a fuel gas as a gas containing hydrogen is supplied to the gas diffusion layer on the anode side and an oxidizing gas as a gas containing oxygen is supplied to the gas diffusion layer on the cathode side, this fuel cell generates electricity.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The inventors of the present invention have focused on the following problems in the manufacturing stage of such fuel cells. Structurally, in a fuel cell, one gas diffusion layer can be joined to the intermediate layer by hot pressing, but the other gas diffusion layer may not be joined to the intermediate layer by hot pressing. In this case, it is necessary to bond the other gas diffusion layer to the intermediate layer with an adhesive.

[0005] Specifically, for example, an adhesive is applied linearly to the intermediate layer, and the gas diffusion layer is bonded to the intermediate layer. However, both sides of the region where the adhesive is applied linearly may become adhesive prohibited regions. Here, examples of the adhesive prohibited regions include, for example, the electrode region and the vicinity of the seal region in the fuel cell.

[0006] Specifically, for example, if the adhesive protrudes into the electrode region, it may have an adverse effect on the internal resistance of the fuel cell and the like. Further, for example, if it protrudes near the seal region, it may have an adverse effect on the sealing performance in the fuel cell.

[0007] From the above, it is necessary to precisely control the region where the adhesive is applied.

[0008] The present invention has been made in view of the above circumstances, and an object thereof is to make it difficult for the adhesive to protrude from a desired application region when bonding the gas diffusion layer to the intermediate layer in the manufacturing stage of the fuel cell.

Means for Solving the Problems

[0009] The present inventors have found that the above object can be achieved by performing predetermined control on the valve of the application part for applying the adhesive and the robot arm for moving it, and thus have arrived at the present invention. The present invention is an adhesive application system as described in the following (1) to (4).

[0010] (1) An adhesive application system for applying an adhesive to an intermediate layer in the manufacturing stage of a fuel cell including the intermediate layer and gas diffusion layers on both sides thereof, an application part for applying the adhesive when the valve is opened, a robot arm configured to be able to move the application part, and a control device for controlling the valve and the robot arm, and the control device linearly applies the adhesive to the intermediate layer from the application start point by opening the valve before the application part is positioned directly above the application start point while moving the application part by the robot arm. Adhesive application system.

[0011] According to this configuration, while moving the coating part, the valve is opened before the coating part reaches directly above the coating start point. Therefore, compared with the case where the coating part is stopped directly above the coating start point to open the valve and the coating part is linearly moved after the adhesive starts to be applied, it is possible to make it difficult to form a liquid pool at the coating start point. From this, when bonding the gas diffusion layer to the intermediate layer, it is possible to prevent the adhesive from overflowing from the desired coating area.

[0012] (2) The adhesive coating system according to (1) above, wherein the control device applies the adhesive to the intermediate layer in a broken line shape as the intermittent linear shape by intermittently opening the valve.

[0013] When applying the adhesive in a solid line shape, there is a limit to narrowing the coating width. In this regard, according to this configuration, by applying the adhesive to the intermediate layer in a broken line shape, it becomes easier to suppress the coating width of the adhesive. Also from this, when bonding the gas diffusion layer to the intermediate layer, it is possible to prevent the adhesive from overflowing from the desired coating area.

[0014] (3) An adhesive coating system for applying an adhesive to an intermediate layer in the manufacturing stage of a fuel cell including the intermediate layer and gas diffusion layers on both sides thereof, a coating part for applying the adhesive when the valve is opened, a robot arm configured to be able to move the coating part, and a control device for controlling the valve and the robot arm, and the control device applies the adhesive to the intermediate layer in a broken line shape by moving the coating part with the robot arm and intermittently opening the valve. Adhesive coating system.

[0015] Also according to this configuration, similar to the case of (2) above, it becomes easier to suppress the coating width of the adhesive. From this, when bonding the gas diffusion layer to the intermediate layer, it is possible to prevent the adhesive from overflowing from the desired coating area.

[0016] (4) The intermediate layer includes an electrolyte membrane and a resin film provided around the electrolyte membrane. The adhesive is a moisture-curing adhesive. The control device applies the adhesive to the resin film. The adhesive application system according to any one of (1) to (3) above.

[0017] The resin film is difficult to absorb moisture, while the gas diffusion layer is easy to absorb moisture. Therefore, in this configuration, when a moisture-curing adhesive is applied to the resin film, the adhesive is difficult to cure. Thereafter, when the gas diffusion layer is brought into contact with the adhesive, the moisture of the gas diffusion layer makes the adhesive easy to cure. Thereby, it becomes easier to appropriately bond the gas diffusion layer to the intermediate layer. Therefore, it becomes easier to suppress the total amount of the adhesive to be applied and to suppress the application width of the adhesive. Therefore, when bonding the gas diffusion layer to the intermediate layer, it is possible to prevent the adhesive from protruding from the desired application area.

Advantages of the Invention

[0018] As described above, according to the configuration of (1) or (3), when bonding the gas diffusion layer to the intermediate layer in the manufacturing stage of the fuel cell, it is possible to prevent the adhesive from protruding from the desired application area. Further, according to the configurations of (2) and (4) that cite (1) or (3), respective additional effects can be obtained.

Brief Description of the Drawings

[0019]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Mode for Carrying Out the Invention

[0020] Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the present invention is not limited to the following embodiments at all, and can be appropriately modified and implemented without departing from the gist of the present invention.

[0021] [First Embodiment] The adhesive application system 50 shown in FIG. 1 is an apparatus for manufacturing the fuel cell 40 shown in FIG. 4. The fuel cell 40 includes, in order from one side, a gas diffusion layer 20a on the anode side, an intermediate layer 30, and a gas diffusion layer 20c on the cathode side. Note that the intermediate layer 30 may be read as "UEA" or "unitized electrode assembly".

[0022] The intermediate layer 30 includes a resin film 32 and an electrolyte membrane 35. The resin film 32 is a film for protecting the edge portion of the electrolyte membrane 35 and is provided around the electrolyte membrane 35. Specifically, the resin film 32 is composed of, for example, two films: a first resin film on the anode side of the electrolyte membrane 35 and a second resin film on the cathode side of the electrolyte membrane 35. As shown in FIG. 5, a film window 32w for exposing a portion other than the edge portion of the electrolyte membrane 35 is formed in the resin film 32.

[0023] As shown in FIG. 4, each gas diffusion layer 20a, 20c includes a carbon paper 23 and a porous layer 26. The porous layer 26 is provided on the side of the intermediate layer 30 rather than the carbon paper 23.

[0024] As shown in FIG. 6, the intermediate layer 30 is larger in size in plan view than the gas diffusion layers 20a and 20c. Therefore, as shown in FIG. 4, the end portions of the intermediate layer 30 protrude from between the gas diffusion layers 20a and 20c. The gas diffusion layer 20a on the anode side is attached to the intermediate layer 30 by thermal pressing. On the other hand, the gas diffusion layer 20c on the cathode side is attached to the intermediate layer 30 with an adhesive A.

[0025] Hereinafter, a gas containing hydrogen is referred to as a "fuel gas", and a gas containing oxygen is referred to as an "oxidizing gas". When the fuel cell 40 shown in FIG. 4 is in use, the electrodes on both sides of the intermediate layer 30, that is, the anode-side electrode and the cathode-side electrode, are electrically connected via a circuit including a power supply target. In this state, when the fuel gas is supplied to the gas diffusion layer 20a on the anode side and the oxidizing gas is supplied to the gas diffusion layer 20c on the cathode side, power generation is performed.

[0026] The adhesive application system 50 shown in FIG. 1 is a system for applying the adhesive A to the cathode-side surface of the intermediate layer 30 in the manufacturing stage of the fuel cell 40 shown in FIG. 4 described above. Specifically, as shown in FIG. 5, the adhesive application system 50 applies the adhesive A in a solid line shape along the film window 32w to both side portions sandwiching the film window 32w in the resin film 32.

[0027] As shown in FIG. 1, the adhesive application system 50 includes an application unit 51, a pressurization system 52, a robot arm 53, and a control device 55.

[0028] The application unit 51 is a dispenser nozzle or the like and stores the adhesive A inside. The adhesive A is a moisture-curing adhesive. The pressurization system 52 is an air pressurization control method or the like and is configured to be able to supply back pressure to the adhesive A in the application unit 51. A valve 51b is provided between the pressurization system 52 and the application unit 51. When the valve 51b opens, the adhesive A is applied from the application unit 51 by the back pressure from the pressurization system 52.

[0029] The robot arm 53 is configured to be movable relative to the coating unit 51. The control device 55 controls the pressurization system 52, the valve 51b, and the robot arm 53.

[0030] Next, problems to be solved in the present embodiment will be described. Hereinafter, a case where the control device 55 shown in FIG. 1 performs control as follows will be referred to as a "comparative form". In the comparative form, the coating unit 51 is stopped directly above a predetermined coating start point Sp, the valve 51b is opened, and when the adhesive A starts to be applied, the coating unit 51 is linearly moved. In this case, due to a delay in the start of movement of the coating unit 51 from the coating start point Sp, as shown in FIG. 2, a liquid pool Ap may be formed at the coating start point Sp.

[0031] In that regard, the control device 55 of the present embodiment shown in FIG. 1 opens the valve 51b before the coating unit 51 reaches a position directly above the coating start point Sp while moving the coating unit 51 shown in FIG. 3 by the robot arm 53. Thereby, the adhesive A is applied in a solid line shape from the coating start point Sp. The timing of opening the valve 51b at this time is controlled based on the viscosity of the adhesive A, the magnitude of the back pressure, and the moving speed of the coating unit 51 to the timing at which the adhesive A is applied to the resin film 32 from the coating start point Sp. Thereafter, the control device 55 closes the valve 51b at a predetermined timing, thereby completing the application of the adhesive A.

[0032] By performing the above operation twice while changing the location where the adhesive A is applied, as shown in FIG. 5, the adhesive A is applied in a solid line shape along the film window 32w to both side portions of the resin film 32 sandwiching the film window 32w. This resin film 32 is difficult to absorb moisture. Therefore, the moisture-curing type adhesive A applied to the upper surface of this resin film 32 is difficult to cure. The manufacturing environment at this time is about 50% RH (23°C).

[0033] Thereafter, the cathode-side gas diffusion layer 20c shown in FIG. 6 is placed on the intermediate layer 30. Specifically, at this time, the porous layer 26 shown in FIG. 4 abuts against the adhesive A. Since the porous layer 26 easily absorbs moisture, it contains sufficient moisture at this point. The moisture in the porous layer 26 makes it easier for the adhesive A to cure.

[0034] The configuration and effects of the present embodiment are summarized below. Hereinafter, the cathode-side gas diffusion layer 20c will be simply referred to as the "gas diffusion layer 20c".

[0035] According to the present embodiment, as shown in FIG. 3, while moving the application part 51, the valve 51b is opened before the application part 51 reaches directly above the application start point Sp. Therefore, when the application part 51 is stopped directly above the application start point Sp and the valve 51b is opened, and then the application part 51 is linearly moved when the adhesive A starts to be applied, that is, compared with the comparative form shown in FIG. 2, as shown in FIG. 3, it is possible to make it difficult to form a liquid pool Ap at the application start point Sp. Therefore, when bonding the cathode-side gas diffusion layer 20c shown in FIG. 6 to the intermediate layer 30 shown in FIG. 5, it is possible to make it difficult for the adhesive A to protrude from the desired application area. Therefore, it is possible to suppress the adhesive A from protruding into the adhesive prohibited area in the fuel cell 40.

[0036] Specifically, examples of the adhesive prohibited area here include, for example, the electrode area and the vicinity of the seal area in the fuel cell 40 shown in FIG. 4. The electrode area is the areas on both sides that sandwich the electrolyte membrane 35 in its thickness direction. On the other hand, the seal area is the joint area between a plurality of cover members (not shown) that cover the intermediate layer 30 and the gas diffusion layers 20a, 20c. Therefore, the vicinity of the seal area is the vicinity of the protruding portion between the gas diffusion layers 20a, 20c in the intermediate layer 30. From these, when applying the adhesive A, the electrode area and the vicinity of the seal area are located on both sides sandwiching the application area in the horizontal direction.

[0037] From the above, according to this embodiment, by making it difficult to form the liquid pool Ap, it is possible to suppress the adhesive A from protruding into the electrode regions and the vicinity of the seal regions on both sides thereof. Therefore, it is possible to suppress the adverse effects such as the adhesive A protruding into the electrode region and affecting the internal resistance of the fuel cell 40, and the adverse effects such as the adhesive A protruding into the vicinity of the seal region and affecting the sealing performance of the fuel cell 40.

[0038] Also, since it is possible to make it difficult to form the liquid pool Ap in this way, as shown in FIG. 6, it is also possible to suppress the variation in the amount of penetration of the adhesive A applied in a solid line shape into each part of the gas diffusion layer 20c. Therefore, it is also possible to suppress the variation in elasticity in each part of the gas diffusion layer 20c.

[0039] Furthermore, the adhesive A shown in FIG. 5 is a moisture-curable adhesive A. As described above, the resin film 32 is difficult to absorb moisture, while the porous layer 26 of the gas diffusion layer 20c is easy to absorb moisture. Therefore, when the moisture-curable adhesive A is applied to the resin film 32 as shown in FIG. 5, it is difficult for the adhesive A to cure. After that, as shown in FIG. 6, when the gas diffusion layer 20c is brought into contact with the adhesive A, the adhesive A becomes easy to cure due to the moisture in the gas diffusion layer 20c. Thereby, it becomes easy to appropriately bond the gas diffusion layer 20c to the intermediate layer 30. Therefore, it becomes easy to suppress the total amount of the adhesive A shown in FIG. 5, and it becomes easy to suppress the coating width W of the adhesive A. Also from this, when bonding the gas diffusion layer 20c shown in FIG. 6 to the intermediate layer 30, it is possible to suppress the adhesive A from protruding from the desired coating region.

[0040] [Second Embodiment] Next, the second embodiment will be described. Regarding this embodiment, the differences from the first embodiment will be mainly described, and the description of the same or similar points as the first embodiment will be appropriately omitted.

[0041] In this embodiment, while moving the application unit 51 with the robot arm 53, the control device 55 shown in FIG. 1 intermittently opens the valve 51b. As a result, as shown in FIG. 7, back pressure from the pressurization system 52 is intermittently applied to the adhesive A in the application unit 51. Thereby, the adhesive A is applied to the resin film 32 in a dashed line shape.

[0042] According to this embodiment, the following effects can be obtained. As shown in FIG. 5, when applying the adhesive A in a solid line shape, there is a limit to reducing the application width W. In this regard, according to this embodiment, by intermittently opening the valve 51b, as shown in FIG. 7, the adhesive A is applied in a dashed line shape. Thereby, it becomes easier to suppress the application width W of the adhesive A. From this also, when bonding the gas diffusion layer 20c to the intermediate layer 30, it is possible to make it difficult for the adhesive A to protrude from the desired application area.

[0043] [Other Embodiments] The embodiments shown above can be modified as follows, for example. In the second embodiment shown in FIG. 7, the movement of the application unit 51 by the robot arm 53 may be temporarily stopped and then the valve 51b may be opened. Even in this case, the effect that it becomes easier to suppress the application width W compared to the case of applying in a solid line shape by applying the adhesive A in a dashed line shape can be obtained.

Explanation of Reference Numerals

[0044] 20c Gas diffusion layer on the cathode side 30 Intermediate layer 32 Resin film 35 Electrolyte membrane 40 Fuel cell 50 Adhesive application system 51 Application unit 51b Valve 53 Robot arm 55 Control device A Adhesive Sp Application start point

Claims

1. An adhesive application system for applying an adhesive to an intermediate layer in a manufacturing stage of a fuel cell including the intermediate layer and gas diffusion layers on both sides thereof, comprising: an application unit that applies the adhesive when a valve is opened; a robot arm configured to be movable for the application unit; a control device that controls the valve and the robot arm, wherein the control device linearly applies the adhesive from an application start point to the intermediate layer by opening the valve before the application unit is positioned directly above the application start point while moving the application unit by the robot arm; an adhesive application system.

2. The adhesive application system according to claim 1, wherein the control device applies the adhesive to the intermediate layer in a broken line shape as the intermittent linear shape by intermittently opening the valve.

3. An adhesive application system for applying an adhesive to an intermediate layer in a manufacturing stage of a fuel cell including the intermediate layer and gas diffusion layers on both sides thereof, comprising: an application unit that applies the adhesive when a valve is opened; a robot arm configured to be movable for the application unit; a control device that controls the valve and the robot arm, wherein the control device applies the adhesive to the intermediate layer in a broken line shape by moving the application unit by the robot arm and intermittently opening the valve; an adhesive application system.

4. The intermediate layer includes an electrolyte membrane and a resin film provided around the electrolyte membrane; the adhesive is a moisture-curing adhesive; the control device applies the adhesive to the resin film; the adhesive application system according to any one of claims 1 to 3.

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