Fuel cell manufacturing method

Abstract

To suppress the formation of bubbles in an adhesion layer even in the case of adapting a pressure-sensitive type adhesive agent.SOLUTION: A manufacturing method of a fuel battery comprises the steps of: forming an adhesion layer by applying a pressure-sensitive type adhesive agent along a defined seal line on a front surface of a support frame for supporting a membrane electrode composite; making a separator approach the front surface of the support frame until it comes into contact with the adhesion layer applied on the support frame; and boding the support frame and the separator with each other by applying a compression force to the support frame and the separator that are in contact via the adhesion layer. In the step of making approach, a distance between the front surface of the adhesion layer and the front surface of the separator that is opposite to the front surface becomes minimum at one specific portion in a cross section that is vertical to a long direction of the seal line, and is monotonously increased as separating from a width direction of the seal line from the one portion.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The technology disclosed in the present specification relates to a method for manufacturing a fuel cell.

Background Art

[0002] Patent Document 1 describes a method for manufacturing a fuel cell. In this manufacturing method, a separator is adhered to the surface of a support frame that supports a membrane-electrode assembly using an adhesive.

Prior Art Literature

Patent Literature

[0003]

Patent Document 1

Summary of the Invention

Problem to be Solved by the Invention

[0004] Conventionally, heat-type adhesives have been used in the manufacture of fuel cells. As an alternative, it is conceivable to employ a pressure-sensitive adhesive. However, with heat-type adhesives, a phase change from solid to liquid occurs during the bonding process, whereas such a phase change does not occur with pressure-sensitive adhesives. Therefore, air bubbles trapped between an adhesive layer formed of a pressure-sensitive adhesive and a separator may remain in the adhesive layer as they are.

[0005] In view of the above circumstances, the present specification provides a technique for suppressing the formation of air bubbles in an adhesive layer even when a pressure-sensitive adhesive is employed.

Means for Solving the Problem

[0006] The technology disclosed herein is embodied in a method for manufacturing a fuel cell. This method for manufacturing a fuel cell comprises the steps of: applying a pressure-sensitive adhesive along a predetermined seal line to the surface of a support frame supporting a membrane electrode composite to form an adhesive layer; bringing a separator close to the surface of the support frame until it contacts the adhesive layer formed on the support frame; and applying a compressive force to the support frame and the separator in contact via the adhesive layer to bond the support frame and the separator to each other. In the bringing step, in a cross section perpendicular to the longitudinal direction of the seal line, the distance between the surface of the adhesive layer and the surface of the separator facing that surface is minimized at a specific location and monotonically increases as it moves away from that location in the width direction of the seal line.

[0007] In the fuel cell manufacturing method described above, the support frame and the separator are bonded to each other via an adhesive layer formed with a pressure-sensitive adhesive. Specifically, first, the pressure-sensitive adhesive is applied to the surface of the support frame along a predetermined seal line to form an adhesive layer. Then, the separator is brought closer to the surface of the support frame until it contacts the adhesive layer on the support frame. At this time, in a cross section perpendicular to the longitudinal direction of the seal line, the distance between the surface of the adhesive layer and the surface of the separator facing that surface is minimized at a specific point and monotonically increases as it moves away from that point in the width direction of the seal line. Subsequently, by applying a compressive force to the support frame and the separator, the support frame and the separator are bonded to each other via the adhesive layer. With this configuration, the adhesive layer and the separator come into contact sequentially along the width direction of the seal line, starting from a specific point where the distance between the surface of the adhesive layer and the surface of the separator is minimized. Therefore, it is possible to suppress the trapping of air bubbles between the adhesive layer and the separator. Furthermore, even if air bubbles are trapped between the adhesive layer and the separator, they can be pushed out from a specific point along the width of the seal line. This suppresses the formation of air bubbles in the adhesive layer formed with pressure-sensitive adhesive.

[0008] In a second embodiment, in the step of forming the adhesive layer in the first embodiment, the adhesive may be applied such that, in a cross section perpendicular to the longitudinal direction of the seal line, the thickness of the adhesive layer is maximum at one point and monotonically decreases as it moves away from that point in the width direction of the seal line. With this configuration, by adjusting the thickness of the adhesive layer in a cross section perpendicular to the longitudinal direction of the seal line, the formation of air bubbles in the adhesive layer can be suppressed.

[0009] In a third embodiment, in the step of forming the adhesive layer in the first or second embodiment, the adhesive may be applied such that the adhesive layer has a symmetrical shape in a cross section perpendicular to the longitudinal direction of the seal line. With this configuration, in a cross section perpendicular to the longitudinal direction of the seal line, the adhesive layer and the separator gradually come into contact from the center of the adhesive layer toward both sides in the width direction. Therefore, it is possible to suppress the trapping of air bubbles between the adhesive layer and the separator, and even if air bubbles are trapped between the adhesive layer and the separator, the air bubbles can be pushed outwards from the center toward both sides in the width direction of the seal line.

[0010] Alternatively, in another embodiment, the point where the adhesive thickness is maximum in a cross section perpendicular to the longitudinal direction of the seal line may be located at one end in the width direction of the seal line. In this case, the thickness of the adhesive layer may monotonically decrease from that point toward the other end. This configuration also suppresses the trapping of air bubbles between the adhesive layer and the separator, and even if air bubbles are trapped between the adhesive layer and the separator, they can be pushed outwards from one end of the seal line toward the other.

[0011] In a fourth embodiment, in any of the first to third embodiments, during the approach step, in a cross-section perpendicular to the longitudinal direction of the seal line, the surface of the separator facing the adhesive layer protrudes toward the adhesive layer, and the amount of protrusion may be maximum at one point and monotonically decrease as it moves away from that point in the width direction of the seal line. With such a configuration, the formation of air bubbles in the adhesive layer can be suppressed by providing a protrusion on the separator.

[0012] In any of the above embodiments, the width of the adhesive layer in a cross section perpendicular to the longitudinal direction of the seal line may be 10 mm or less. In addition to this, or alternatively, a difference of 20 micrometers or more may be provided between the maximum and minimum thickness of the adhesive layer in a cross section perpendicular to the longitudinal direction of the seal line. These configurations can more effectively suppress the formation of air bubbles in the adhesive layer.

[0013] In any of the above embodiments, the viscoelastic properties of the adhesive constituting the adhesive layer are 10 5 10 from Mpa 7 The pressure may be within a range of up to MPa. Even when using such an adhesive, the formation of air bubbles in the adhesive layer can be suppressed according to the techniques disclosed herein.

[0014] The technology disclosed herein is also embodied in other fuel cell manufacturing methods. This fuel cell manufacturing method comprises the steps of: applying a pressure-sensitive adhesive along a predetermined seal line to the surface of a first separator constituting a fuel cell to form an adhesive layer; bringing a second separator constituting another fuel cell to the surface of the first separator until it contacts the adhesive layer formed on the first separator; and applying a compressive force to the first separator and the second separator in contact via the adhesive layer to bond the first separator and the second separator to each other. In the bringing step, in a cross section perpendicular to the longitudinal direction of the seal line, the distance between the surface of the adhesive layer and the surface of the second separator facing that surface is minimized at a specific point and monotonically increases as it moves away from that point in the width direction of the seal line.

[0015] In the fuel cell manufacturing method described above, a first separator constituting a fuel cell cell and a second separator constituting another fuel cell cell are bonded to each other via an adhesive layer formed with a pressure-sensitive adhesive. In other words, the fuel cell manufacturing method described above differs from the previously described fuel cell manufacturing method in that the adherends bonded via the adhesive layer are changed. Even with this configuration, the adhesive layer and the second separator come into sequential contact along the width direction of the seal line, starting from a specific point where the distance between the surface of the adhesive layer and the surface of the second separator is minimized. Therefore, the formation of air bubbles in the adhesive layer can be suppressed. [Brief explanation of the drawing]

[0016] [Figure 1] A diagram showing the schematic configuration of the fuel cell 10 in the embodiment. [Figure 2] An exploded view showing the schematic configuration of fuel cell cell 12. [Figure 3] A diagram showing an adhesive layer 24 applied to the surface of a support frame 20 along a defined seal line. That is, the area to which the adhesive layer 24 is applied indicates the defined seal line. [Figure 4]Figures 4(A)-(C) show the flow of the manufacturing method of the fuel cell 10. Figure 4(A) is a cross-sectional view along line IV-IV. Figure 4(B) shows the process of bringing the separators 16 and 18 closer to the surface of the support frame 20. Figure 4(C) shows the adhesion between the support frame 20 and the separators 16 and 18 via adhesive layers 24 and 26. [Figure 5] Figures 5(A)-(C) show several modified examples of adhesive layers 24 and 26, each corresponding to the cross-sectional view in Figure 4(A). [Figure 6] Figures 6(A) and (B) show modified examples in which the adhesive layers 24 and 26 are replaced with the separators 16 and 18, which correspond to the cross-sectional views in Figure 4(A), respectively. [Figure 7] Figures 7(A)-(C) show the flow of other manufacturing methods for the fuel cell 10. [Modes for carrying out the invention]

[0017] An embodiment of the fuel cell 10 and its manufacturing method will be described with reference to the drawings. As shown in Figure 1, the fuel cell 10 comprises a plurality of fuel cell cells 12. Each fuel cell cell 12 is arranged parallel to the X and Z axes, and the plurality of fuel cell cells 12 are stacked along the Y axis. As will be described in more detail later, each fuel cell cell 12 is a component capable of generating electricity independently. The fuel cell 10 is not particularly limited, but can be used, for example, in vehicles that use fuel cells as a power source, such as fuel cell vehicles.

[0018] As shown in FIG. 2, each fuel cell 12 includes a membrane electrode assembly (MEA) 14, an anode-side separator 16, a cathode-side separator 18, and a support frame 20. Although not shown in the figure, the MEA 14 includes an electrolyte membrane, an anode catalyst layer provided on one surface of the electrolyte membrane, and a cathode catalyst layer provided on the other surface of the electrolyte membrane. The MEA 14 is supported by the support frame 20. The MEA 14, together with the support frame 20, is disposed between the anode-side separator 16 and the cathode-side separator 18. Although not particularly limited, each fuel cell 12 may further include an anode-side gas diffusion layer and a cathode-side gas diffusion layer on both surfaces of the MEA 14. That is, the MEA 14, together with the anode-side gas diffusion layer and the cathode-side gas diffusion layer, may constitute a membrane electrode and gas diffusion layer assembly (MEGA).

[0019] The anode-side separator 16 and the cathode-side separator 18 are plate-shaped members made of a gas-impermeable conductive material. Although not particularly limited, each of the separators 16 and 18 may be formed using a metal plate such as titanium or stainless steel, for example. Each of the separators 16 and 18 includes six manifold holes 28a to 28f. These manifold holes 28a to 28f constitute manifolds 30a, 30c, and 30e that respectively supply hydrogen gas, air, and a cooling medium to each fuel cell 12, and manifolds 30b, 30d, and 30f that respectively recover unreacted hydrogen gas, unreacted air, and the cooling medium from each fuel cell 12.

[0020] As shown in FIGS. 2 and 3, the support frame 20 has a frame shape including an opening 22. The MEA 14 is disposed in the opening 22 of the support frame 20. The support frame 20 surrounds the periphery of the MEA 14. Although not particularly limited, the support frame 20 is formed of a thermosetting resin such as an epoxy resin or a phenol resin. Similarly to the separators 16 and 18 described above, the support frame 20 is also provided with six manifold holes 28a to 28f.

[0021] One surface 20a of the support frame 20 faces the anode-side separator 16, and is bonded to the anode-side separator 16 via the first adhesive layer 24. The first adhesive layer 24 is formed of a pressure-sensitive adhesive (PSA). The first adhesive layer 24 is provided along a predetermined seal line on the one surface 20a of the support frame 20. The seal line of the first adhesive layer 24 is defined so as to surround the opening 22 of the support frame 20 and each of the manifold holes 28a to 28f. The other surface 20b of the support frame 20 faces the cathode-side separator 18, and is bonded to the cathode-side separator 18 via the second adhesive layer 26 (see FIGS. 4(A) to (C)). The second adhesive layer 26 is also formed of a pressure-sensitive adhesive (PSA). The second adhesive layer 26 is provided along a predetermined seal line on the other surface 20b of the support frame 20. The seal line of the second adhesive layer 26 is also defined so as to surround the opening 22 of the support frame 20 and each of the manifold holes 28a to 28f.

[0022] The manufacturing method for the fuel cell 10 will be described with reference to Figures 3 and 4. As shown in Figures 3 and 4(A), the manufacturing method includes a step of forming adhesive layers 24 and 26 on each surface 20a and 20b of the support frame 20 that supports the MEA 14. In this step, a pressure-sensitive adhesive is applied to each surface 20a and 20b of the support frame 20 along a predetermined seal line. This forms adhesive layers 24 and 26 on each surface 20a and 20b of the support frame 20, respectively. The specific method for applying the adhesive is not particularly limited. For example, the adhesive can be applied by inkjet printing, screen printing, or the like.

[0023] As shown in Figure 4(A), in the process of forming the adhesive layers 24 and 26, the adhesive is applied such that the surfaces of the adhesive layers 24 and 26 are convex in a cross section perpendicular to the longitudinal direction of the seal line. As a result, for example, the thickness of the first adhesive layer 24 is maximum at a first point P1 and monotonically decreases as it moves away from the first point P1 in the width direction (i.e., the X direction) of the seal line. Monotonically decreasing here means a continuous or intermittent decrease, and does not increase. The position of the first point P1 where the thickness of the first adhesive layer 24 is maximum is not particularly limited. For example, in the first adhesive layer 24 of this embodiment, the first point P1 is located in the center in the width direction (i.e., the X direction) in a cross section perpendicular to the longitudinal direction of the seal line, and the first adhesive layer 24 has a symmetrical shape. Similarly, the thickness of the second adhesive layer 26 is maximum at the second point P2 and monotonically decreases as it moves away from the second point P2 in the width direction (i.e., the X direction) of the seal line. Here, in a cross section perpendicular to the longitudinal direction of the seal line, the shape of the second adhesive layer 26 may be vertically symmetrical or asymmetrical with respect to the shape of the first adhesive layer 24.

[0024] Next, as shown in Figure 4(B), the manufacturing method includes a step of bringing the separators 16 and 18 closer to the respective surfaces 20a and 20b of the support frame 20. In this step, the separators 16 and 18 are brought closer to the respective surfaces 20a and 20b of the support frame 20 until they contact the adhesive layers 24 and 26 on the support frame 20. As a result, the anode-side separator 16 is positioned by contacting the first adhesive layer 24 on one surface 20a of the support frame 20. The cathode-side separator 18 is positioned by contacting the second adhesive layer 26 formed on the other surface 20b of the support frame 20.

[0025] As described above, the surfaces of the adhesive layers 24 and 26 have a convex shape. Therefore, as the anode-side separator 16 approaches the first adhesive layer 24, the distance between the surface of the first adhesive layer 24 and the surface of the anode-side separator 16 facing that surface, in a cross section perpendicular to the longitudinal direction of the seal line, is minimized at the first point P1 and monotonically increases as it moves away from the first point P1 in the width direction (i.e., the X direction) of the seal line. Monotonically increasing here means a continuous or intermittent increase, and does not decrease. Similarly, in a cross section perpendicular to the longitudinal direction of the seal line, the distance between the surface of the second adhesive layer 26 and the surface of the cathode-side separator 18 facing that surface is minimized at the second point P2 and monotonically increases as it moves away from the second point P2 in the width direction (i.e., the X direction) of the seal line.

[0026] According to the above configuration, the surfaces of the adhesive layers 24 and 26 first begin contact with the surfaces of the separators 16 and 18 at the first point P1 and the second point P2. Subsequently, the surfaces of the adhesive layers 24 and 26 gradually come into contact with the separators 16 and 18 toward both sides in the width direction (i.e., the X direction) of the seal line. Therefore, it is possible to suppress the trapping of air bubbles between the adhesive layers 24 and 26 and the separators 16 and 18. Furthermore, even if air bubbles are trapped between the adhesive layers 24 and 26 and the separators 16 and 18, the bubbles can be pushed outwards from a specific point (i.e., the first point P1 and the second point P2) toward both sides in the width direction of the seal line. This suppresses the formation of air bubbles in the adhesive layers 24 and 26 formed with pressure-sensitive adhesive.

[0027] Subsequently, as shown in Figure 4(C), the manufacturing method includes a step of bonding the support frame 20 and the separators 16 and 18 to each other. In this step, a compressive force is applied to the support frame 20 and the separators 16 and 18 that are in contact via adhesive layers 24 and 26. As a result, the anode-side separator 16 is bonded to the support frame 20 via the first adhesive layer 24, and the cathode-side separator 18 is bonded to the support frame 20 via the second adhesive layer 26. The method of bringing the separators 16 and 18 closer to the support frame 20, and the method of applying compressive force to the support frame 20 and the separators 16 and 18 are not particularly limited. For example, a press or the like can be used in these steps.

[0028] Figures 5(A)-(C) show several variations of the adhesive layers 24 and 26. As shown in Figure 5(A), in a cross section perpendicular to the longitudinal direction of the seal line, the adhesive layers 24 and 26 formed on the support frame 20 may have a shape in which part or all of their surfaces are curved in a concave shape. Alternatively, as shown in Figures 5(B) and (C), in a cross section perpendicular to the longitudinal direction of the seal line, the adhesive layers 24 and 26 formed on the support frame 20 may have a shape in which the thickness is greatest at the ends in the width direction. In this case, the two adhesive layers 24 and 26 may have shapes that are asymmetrical vertically (see Figure 5(B)) or shapes that are symmetrical vertically (see Figure 5(C)).

[0029] As described above, the adhesive layers 24 and 26 are formed to surround the opening 22 of the support frame 20 and the respective manifold holes 28a-28f. In this case, the adhesive layers 24 and 26 have sections adjacent to the manifold holes 28a-28f and sections not adjacent to the manifold holes 28a-28f. Near the manifold holes 28a-28f, the pressure acting on the adhesive layers 24 and 26 is relatively high. For this reason, the width and / or thickness of the first adhesive layer 24 may be larger in the sections adjacent to the manifold holes 28a-28f than in the sections not adjacent to the manifold holes 28a-28f.

[0030] In the above-described embodiments and modifications, each of the two adhesive layers 24 and 26 has a shape in which its thickness changes in the width direction. In contrast, in other embodiments, only one of the two adhesive layers 24 and 26 may have a shape in which its thickness changes in the width direction. That is, the other of the two adhesive layers 24 and 26 may have a shape in which its thickness is constant in the width direction.

[0031] In the embodiments and modifications described above, each of the two adhesive layers 24 and 26 has a shape in which the thickness changes in the width direction. In contrast, as shown in Figures 6(A) and (B), in other embodiments, the above-mentioned profile provided on the surface of the adhesive layers 24 and 26 may be provided on the surface of the separators 16 and 18 that come into contact with the adhesive layers 24 and 26. That is, the surfaces of the separators 16 and 18 may each be provided with protrusions 32 that project toward the adhesive layers 24 and 26. In this case, the amount of protrusion of the protruding portion 32 is preferably maximum at a specific location Q1, Q2, and monotonically decreases as it moves away from that location Q1, Q2 in the width direction (i.e., the X direction) of the seal line.

[0032] Even with this configuration, as the anode-side separator 16 approaches the first adhesive layer 24, the distance between the surface of the first adhesive layer 24 and the surface of the anode-side separator 16 facing that surface, in a cross section perpendicular to the longitudinal direction of the seal line, is minimized at the single point Q1 and monotonically increases as it moves away from the single point Q1 in the width direction (i.e., the X direction) of the seal line. This suppresses the formation of air bubbles in the adhesive layers 24 and 26.

[0033] In this embodiment, the support frame 20 and the separators 16 and 18 are bonded to each other via adhesive layers 24 and 26 formed of a pressure-sensitive adhesive. Alternatively, or in addition to this, the anode-side separator 16 of the fuel cell cell 12 and the cathode-side separator 18 of the adjacent fuel cell cell 12 may be bonded to each other via adhesive layers 24 and 26 formed of a pressure-sensitive adhesive.

[0034] In this case, as shown in Figure 7(A), the manufacturing method includes a step of forming a third adhesive layer 34 on the surface of the anode-side separator 16. In this step, a pressure-sensitive adhesive is applied along the seal line defined on the anode-side separator 16. The third adhesive layer 34 may have a shape in which the thickness changes in the width direction, similar to the adhesive layers 24 and 26 described above (see Figures 4 and 5).

[0035] Next, as shown in Figure 7(B), the manufacturing method includes a step of bringing the cathode-side separator 18 of another fuel cell cell 12 close to the surface of the anode-side separator 16. In this step, the cathode-side separator 18 is brought closer to the anode-side separator 16 until it contacts the third adhesive layer 34 on the anode-side separator 16. As a result, the cathode-side separator 18 is positioned in contact with the third adhesive layer 34 on the anode-side separator 16. This step may be performed simultaneously with the step shown in Figure 4(B) above.

[0036] The third adhesive layer 34 has a shape in which its thickness changes in the width direction (i.e., the X direction) of the seal line. Therefore, as the cathode-side separator 18 approaches the third adhesive layer 34, the distance between the surface of the third adhesive layer 34 and the surface of the cathode-side separator 18 facing that surface, in a cross section perpendicular to the longitudinal direction of the seal line, is minimized at a specific point R1 and monotonically increases as it moves away from that point R1 in the width direction of the seal line. As a result, the formation of air bubbles is suppressed even in the third adhesive layer 34 which is formed of a pressure-sensitive adhesive.

[0037] Next, as shown in Figure 7(C), the manufacturing method includes a step of bonding the two separators 16 and 18 to each other. In this step, a compressive force is applied to the two separators 16 and 18 that are in contact via the third adhesive layer 34. As a result, the two separators 16 and 18 are bonded to each other via the third adhesive layer 34. Consequently, the two separators 16 and 18 are sealed by the third adhesive layer 34, and the gasket required between the two separators 16 and 18 can be omitted. This step may be performed simultaneously with the step shown in Figure 4(C) above.

[0038] In this embodiment, the anode-side separator 16 is an example of the first separator in this technology, and the cathode-side separator 18 in this embodiment is an example of the second separator in this technology. As a modification, the third adhesive layer 34 may be formed on the cathode-side separator 18 instead of the anode-side separator 16.

[0039] Although several specific examples have been described in detail above, these are merely illustrative and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes to the specific examples illustrated above. The technical elements described in this specification or in the drawings exhibit technical usefulness individually or in combination. [Explanation of Symbols]

[0040] 10: Fuel cell, 12: Fuel cell cell, 14: MEA, 16, 18: Separator, 20: Support frame, 20a, 20b: Surface, 22: Opening, 24, 26: Adhesive layer, 28a-28f: Manifold hole, 32: Protrusion, 34: Adhesive layer

Claims

1. A method for manufacturing a fuel cell, The process involves applying a pressure-sensitive adhesive along a predetermined seal line to the surface of a support frame that supports a membrane electrode composite to form an adhesive layer, The step of bringing the separator closer to the surface of the support frame until it contacts the adhesive layer formed on the support frame, A step of applying compressive force to the support frame and the separator that are in contact via the adhesive layer, thereby bonding the support frame and the separator to each other. Equipped with, In the aforementioned bringing-to-close step, in a cross-section perpendicular to the longitudinal direction of the seal line, the distance between the surface of the adhesive layer and the surface of the separator facing that surface is minimized at a specific location and monotonically increases as it moves away from that location in the width direction of the seal line. Manufacturing method.

2. The method for manufacturing a fuel cell according to claim 1, wherein in the step of forming the adhesive layer, the adhesive is applied such that, in the cross section perpendicular to the longitudinal direction of the seal line, the thickness of the adhesive layer is maximum at one location and monotonically decreases as it moves away from that location in the width direction of the seal line.

3. The method for manufacturing a fuel cell according to claim 2, wherein in the step of forming the adhesive layer, the adhesive is applied such that the adhesive layer has a symmetrical shape in the cross section perpendicular to the longitudinal direction of the seal line.

4. A method for manufacturing a fuel cell according to any one of claims 1 to 3, wherein in the step of bringing the seal line closer together, in the cross section perpendicular to the longitudinal direction of the seal line, the surface of the separator facing the adhesive layer protrudes toward the adhesive layer, the amount of protrusion is greatest at one location and decreases monotonically as it moves away from that location in the width direction of the seal line.

5. A method for manufacturing a fuel cell, A step of applying a pressure-sensitive adhesive along a predetermined seal line to the surface of a first separator constituting a fuel cell to form an adhesive layer, A step of bringing a second separator, which constitutes another fuel cell cell, closer to the surface of the first separator until it comes into contact with the adhesive layer formed on the first separator, A step of applying compressive force to the first separator and the second separator that are in contact via the adhesive layer, thereby bonding the first separator and the second separator to each other. Equipped with, In the aforementioned bringing-to-close step, in a cross-section perpendicular to the longitudinal direction of the seal line, the distance between the surface of the adhesive layer and the surface of the second separator facing that surface is minimized at a specific location and monotonically increases as it moves away from that location in the width direction of the seal line. A method for manufacturing fuel cells.

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