Method for manufacturing fuel cell

Abstract

The present invention relates to a method for manufacturing a fuel cell, which can suppress the formation of air bubbles in an adhesive layer even when a pressure-sensitive adhesive is used. This method for manufacturing a fuel cell is provided with: a step for forming an adhesive layer by applying a pressure-sensitive adhesive along a predetermined sealing line on the surface of a support frame that supports a membrane electrode assembly; a step for bringing the diaphragm toward the surface of the support frame until the diaphragm comes into contact with the adhesive layer applied to the support frame; and a step in which a compressive force is applied to the support frame and the diaphragm which are in contact with each other by the adhesive layer, and the support frame and the diaphragm are adhered to each other. In the approaching step, in a cross section perpendicular to the longitudinal direction of the sealing line, the distance between the surface of the adhesive layer and the surface of the diaphragm facing the surface of the adhesive layer is minimum at a specific position and monotonically increases as the distance is separated from the specific position in the width direction of the sealing line.

Description

Technical Field

[0001] The technology disclosed in this 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 method, a separator is bonded to a surface of a support frame that supports a membrane electrode assembly using an adhesive.

[0003] Patent Document 1: Japanese Patent Application Publication No. 2020-113391

[0004] In the past, heating type adhesives were used in the manufacture of fuel cells. Instead, pressure-sensitive adhesives may be used. However, in heating type adhesives, a phase change from solid to liquid occurs during the bonding process, whereas in pressure-sensitive adhesives, such a phase change does not occur. Therefore, there is a concern that bubbles trapped between the adhesive layer formed by the pressure-sensitive adhesive and the diaphragm remain in the adhesive layer as they are. Summary of the invention

[0005] In view of the above-mentioned actual situation, this specification provides a technology for suppressing the formation of bubbles in the adhesive layer even when a pressure-sensitive adhesive is used.

[0006] The technology disclosed in this specification can be embodied as a method for manufacturing a fuel cell. The method for manufacturing a fuel cell comprises: a step of applying a pressure-sensitive adhesive along a predetermined sealing line on the surface of a support frame supporting a membrane electrode assembly to form an adhesive layer; a step of bringing the diaphragm close to the surface of the support frame until it contacts the adhesive layer formed on the support frame; and a step of applying a compressive force to the support frame and the diaphragm that are in contact through the adhesive layer to bond the support frame and the diaphragm to each other. In the approaching step, in a cross section perpendicular to the length direction of the sealing line, the distance between the surface of the adhesive layer and the surface of the diaphragm opposite to the surface is minimum at a specific position and increases monotonically as it moves away from the position in the width direction of the sealing line.

[0007] In the above-mentioned method for manufacturing a fuel cell, the support frame and the diaphragm are bonded to each other by an adhesive layer formed by a pressure-sensitive adhesive. In detail, the pressure-sensitive adhesive is first applied to the surface of the support frame along a predetermined sealing line to form an adhesive layer. Then, the diaphragm is gradually brought closer to the surface of the support frame until the diaphragm contacts the adhesive layer on the support frame. At this time, in a cross-section perpendicular to the length direction of the sealing line, the distance between the surface of the adhesive layer and the surface of the diaphragm opposite to the surface is the smallest at a specific position, and increases monotonically as it moves away from the position in the width direction of the sealing line. Then, by applying a compressive force to the support frame and the diaphragm, the support frame and the diaphragm are bonded to each other by the adhesive layer. According to such a structure, the adhesive layer and the diaphragm are in contact with each other in sequence along the width direction of the sealing line from a specific position where the distance between the surface of the adhesive layer and the surface of the diaphragm is the smallest. Therefore, it is possible to suppress bubbles from being captured between the adhesive layer and the diaphragm. Furthermore, even if bubbles are trapped between the adhesive layer and the diaphragm, the bubbles can be pushed out from a specific position along the width direction of the seal line. Thus, the formation of bubbles in the adhesive layer formed by the pressure-sensitive adhesive can be suppressed.

[0008] The second method can be completed on the basis of the first method, and in the process of forming the adhesive layer, the adhesive is applied in such a manner that the thickness of the adhesive layer is the largest at one position in the cross section perpendicular to the length direction of the sealing line and decreases monotonically as it moves away from the one position in the width direction of the sealing line. According to such a configuration, the formation of bubbles in the adhesive layer can be suppressed by adjusting the thickness of the adhesive layer in the cross section perpendicular to the length direction of the sealing line.

[0009] The third method can be completed on the basis of the first or second method, and in the process of forming the adhesive layer, the adhesive is applied in a manner that the adhesive layer has a bilaterally symmetrical shape in a cross section perpendicular to the length direction of the sealing line. According to such a configuration, in a cross section perpendicular to the length direction of the sealing line, the adhesive layer and the diaphragm gradually contact from the center of the adhesive layer toward both sides in the width direction. Therefore, it is possible to prevent bubbles from being captured between the adhesive layer and the diaphragm, and even if bubbles are captured between the adhesive layer and the diaphragm, the bubbles can be pressed out from the center toward both sides in the width direction of the sealing line.

[0010] Alternatively, as another embodiment, in a cross section perpendicular to the length direction of the sealing line, a position where the thickness of the adhesive is the largest may be located at one end of the sealing line in the width direction. In this case, the thickness of the adhesive layer may decrease monotonically from the one position toward the other end. With such a configuration, it is also possible to prevent bubbles from being captured between the adhesive layer and the diaphragm, and even if bubbles are captured between the adhesive layer and the diaphragm, the bubbles can be pressed out from one end of the sealing line toward the other end.

[0011] The fourth mode can be completed on the basis of any one of the first to third modes, wherein in the approaching process, in a cross section perpendicular to the longitudinal direction of the sealing line, the surface of the diaphragm facing the adhesive layer protrudes toward the adhesive layer, and the protrusion amount is the largest at one position and decreases monotonically as it moves away from the one position in the width direction of the sealing line. According to such a configuration, by providing the protruding portion on the diaphragm, it is possible to suppress the formation of bubbles in the adhesive layer.

[0012] In any of the above-mentioned embodiments, the width of the adhesive layer in the cross section perpendicular to the longitudinal direction of the sealing line may be 10 mm or less. In addition or alternatively, a difference of 20 microns or more may be set between the maximum thickness and the minimum thickness of the adhesive layer in the cross section perpendicular to the longitudinal direction of the sealing line. According to the above-mentioned configuration, the formation of bubbles in the adhesive layer can be more effectively suppressed.

[0013] In any of the above-mentioned embodiments, the viscoelastic properties of the adhesive constituting the adhesive layer may be 10 5 Mpa~10 7 Even when such an adhesive is used, the technology disclosed in this specification can suppress the formation of bubbles in the adhesive layer.

[0014] The technology disclosed in this specification can also be embodied as other methods for manufacturing fuel cells. The method for manufacturing a fuel cell comprises: a process of applying a pressure-sensitive adhesive on the surface of the first diaphragm constituting the fuel cell cell along a predetermined sealing line to form an adhesive layer; a process of bringing the second diaphragm constituting other fuel cell cells close to the surface of the first diaphragm until it contacts the adhesive layer formed on the first diaphragm; and a process of applying a compressive force to the first diaphragm and the second diaphragm contacted by the adhesive layer to bond the first diaphragm and the second diaphragm to each other. In the above approaching process, in a cross section perpendicular to the length direction of the sealing line, the distance between the surface of the adhesive layer and the surface of the second diaphragm opposite to the surface is the smallest at a specific position, and increases monotonically as it moves away from the one position in the width direction of the sealing line.

[0015] In the above-mentioned method for manufacturing a fuel cell, the first diaphragm constituting the fuel cell and the second diaphragm constituting the other fuel cell are bonded to each other by an adhesive layer formed by a pressure-sensitive adhesive. That is, the above-mentioned method for manufacturing a fuel cell changes the adherend bonded by the adhesive layer compared to the above-mentioned method for manufacturing a fuel cell. With such a structure, the adhesive layer and the second diaphragm also gradually contact each other along the width direction of the sealing line from a specific position where the distance between the surface of the adhesive layer and the surface of the second diaphragm is the smallest. Therefore, the formation of bubbles in the adhesive layer can be suppressed. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 1 is a diagram showing a schematic configuration of a fuel cell 10 according to an embodiment.

[0017] Figure 2 It is an exploded view showing the schematic structure of the fuel cell 12 .

[0018] Figure 3 The figure shows the adhesive layer 24 applied along the predetermined seal line on the surface of the support frame 20. That is, the range where the adhesive layer 24 is applied represents the predetermined seal line.

[0019] Figure 4 (A) to (C) in FIG. 1 show the flow of the method for manufacturing the fuel cell 10 . Figure 4 (A) is a cross-sectional view taken along line IV-IV. Figure 4 (B) in FIG. 1 is a diagram showing a step of bringing the diaphragms 16 and 18 closer to the surface of the support frame 20 . Figure 4 (C) is a diagram showing that the support frame 20 and the diaphragms 16 , 18 are bonded to each other via the adhesive layers 24 , 26 .

[0020] Figure 5 (A) to (C) in FIG. 2 represent several modified examples of the adhesive layers 24 and 26, respectively. Figure 4 The cross-sectional view of (A) corresponds to FIG.

[0021] Figure 6 (A) and (B) in the figure represent modified examples in which the protrusions 32 are provided on the diaphragms 16 and 18 instead of the adhesive layers 24 and 26, respectively. Figure 4 The cross-sectional view of (A) corresponds to FIG.

[0022] Figure 7 (A) to (C) in FIG. 1 show the flow of another method for manufacturing the fuel cell 10 . DETAILED DESCRIPTION

[0023] The fuel cell 10 and the manufacturing method thereof of the embodiment will be described with reference to the accompanying drawings. Figure 1 As shown, the fuel cell 10 includes a plurality of fuel cell cells 12. Each fuel cell cell 12 is arranged parallel to the X-axis and the Z-axis, and the plurality of fuel cell cells 12 are stacked along the Y-axis. The details will be described later, but each of the fuel cell cells 12 is a component capable of generating electricity independently. The fuel cell 10 is not particularly limited, and can be used in a vehicle such as a fuel cell vehicle that uses a fuel cell as a power source.

[0024] like Figure 2As shown, each fuel cell 12 includes a membrane electrode assembly (MEA) 14, an anode side diaphragm 16, a cathode side diaphragm 18, and a support frame 20. Although not shown in the figure, MEA14 includes an electrolyte membrane, an anode catalyst layer disposed on the surface of one side of the electrolyte membrane, and a catalyst layer disposed on the surface of the other side of the electrolyte membrane. MEA14 is supported by the support frame 20. MEA14 and the support frame 20 are arranged between the anode side diaphragm 16 and the cathode side diaphragm 18. Although not particularly limited, each fuel cell 12 can also include an anode side gas diffusion layer and a cathode side gas diffusion layer on both sides of MEA14. That is, MEA14 can constitute a membrane electrode gas diffusion layer assembly (MEGA) together with the anode side gas diffusion layer and the cathode side gas diffusion layer.

[0025] The anode side diaphragm 16 and the cathode side diaphragm 18 are plate-shaped components, and are made of an air-impermeable conductive material. Although not particularly limited, each diaphragm 16, 18 can be made of a metal plate such as titanium or stainless steel. Each diaphragm 16, 18 has six manifold holes 28a-28f. These manifold holes 28a-28f constitute manifolds 30a, 30c, 30e for supplying hydrogen, air, and a cooling medium to each fuel cell 12, and manifolds 30b, 30d, 30f for recovering unreacted hydrogen, unreacted air, and a cooling medium from each fuel cell 12.

[0026] like Figure 2 , 3 As shown, the support frame 20 has a frame shape with an opening 22. The MEA 14 is arranged in the opening 22 of the support frame 20. The support frame 20 surrounds the MEA 14. Although not particularly limited, the support frame 20 is made of a thermosetting resin such as epoxy resin or phenolic resin. The support frame 20 is also provided with six manifold holes 28a-28f, similar to the diaphragms 16 and 18 described above.

[0027] The surface 20a of one side of the support frame 20 is opposite to the anode side diaphragm 16, and is bonded to the anode side diaphragm 16 via a first adhesive layer 24. The first adhesive layer 24 is made of a pressure-sensitive adhesive (PSA). The first adhesive layer 24 is provided along a predetermined sealing line in the surface 20a of one side of the support frame 20. The sealing line of the first adhesive layer 24 is defined as surrounding the opening 22 of the support frame 20 and each manifold hole 28a-28f. The surface 20b of the other side of the support frame 20 is opposite to the cathode side diaphragm 18, and is bonded to the cathode side diaphragm 18 via a second adhesive layer 26 (see Figure 4 (A)-(C)) in the support frame 20 are bonded to the cathode side diaphragm 18. The second adhesive layer 26 is also composed of a pressure-sensitive adhesive (PSA). The second adhesive layer 26 is provided along a predetermined sealing line in the other surface 20b of the support frame 20. The sealing line of the second adhesive layer 26 is also determined to surround the opening 22 of the support frame 20 and each manifold hole 28a-28f.

[0028] Reference Figure 3 , 4 A method for manufacturing the fuel cell 10 is described. Figure 3 , Figure 4 As shown in (A) in the figure, the manufacturing method includes a step of forming adhesive layers 24 and 26 on each surface 20a and 20b of the support frame 20 supporting 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 sealing line. Thus, adhesive layers 24 and 26 are formed on each surface 20a and 20b of the support frame 20, respectively. There is no particular limitation on the specific method of applying the adhesive. As an example, the application of the adhesive can be performed by inkjet printing, screen printing, etc.

[0029] like Figure 4As shown in (A), in the process of forming the adhesive layers 24 and 26, the adhesive is applied in such a manner that the surfaces of the adhesive layers 24 and 26 are convex in the cross section perpendicular to the length direction of the sealing line. Thus, for example, the thickness of the first adhesive layer 24 is maximum at the first point P1, and decreases monotonically as it moves away from the first point P1 in the width direction of the sealing line (i.e., the X direction). The monotonic decrease mentioned here is a continuous or intermittent decrease, which means no increase. Among them, the position of the first point P1 where the thickness of the first adhesive layer 24 is maximum is not particularly limited. As an example, in the first adhesive layer 24 of the present embodiment, in the cross section perpendicular to the length direction of the sealing line, the first point P1 is located in the center of the width direction (i.e., the X direction), and the first adhesive layer 24 has a left-right symmetrical shape. Similarly, the thickness of the second adhesive layer 26 is maximum at the second point P2, and decreases monotonically as it moves away from the second point P2 in the width direction of the sealing line (i.e., the X direction). Here, in the 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 to the shape of the first adhesive layer 24 .

[0030] Next, if Figure 4 As shown in (B) in FIG. 1 , the manufacturing method includes a step of bringing the diaphragms 16 and 18 close to the surfaces 20a and 20b of the support frame 20, respectively. In this step, the diaphragms 16 and 18 are gradually brought close to the surfaces 20a and 20b of the support frame 20 until they come into contact with the adhesive layers 24 and 26 on the support frame 20. Thus, the anode-side diaphragm 16 comes into contact with the first adhesive layer 24 on the surface 20a of one side of the support frame 20 and is positioned. The cathode-side diaphragm 18 comes into contact with the second adhesive layer 26 formed on the other surface 20b of the support frame 20 and is positioned.

[0031] As described above, each surface of the adhesive layers 24 and 26 has a convex shape. Therefore, when the anode side diaphragm 16 gradually approaches the first adhesive layer 24, in the cross section perpendicular to the length direction of the sealing line, the distance between the surface of the first adhesive layer 24 and the surface of the anode side diaphragm 16 opposite to the surface is the smallest at the first point P1, and increases monotonically as it moves away from the first point P1 in the width direction of the sealing line (i.e., the X direction). The monotonic increase mentioned here is a continuous or intermittent increase, which means no decrease. Similarly, in the cross section perpendicular to the length direction of the sealing line, the distance between the surface of the second adhesive layer 26 and the surface of the cathode side diaphragm 18 opposite to the surface is also the smallest at the second point P2, and increases monotonically as it moves away from the second point P2 in the width direction of the sealing line (i.e., the X direction).

[0032] According to the above-mentioned structure, the surfaces of the adhesive layers 24 and 26 first begin to contact the surfaces of the diaphragms 16 and 18 at the first point P1 and the second point P2. Then, the surfaces of the adhesive layers 24 and 26 gradually contact the diaphragms 16 and 18 on both sides of the width direction (i.e., the X direction) of the sealing line. Therefore, it is possible to prevent bubbles from being captured between the adhesive layers 24 and 26 and the diaphragms 16 and 18. In addition, even if bubbles are captured between the adhesive layers 24 and 26 and the diaphragms 16 and 18, the bubbles can be pressed outward from a specific position (i.e., the first point P1 and the second point P2) toward both sides of the width direction of the sealing line. Thus, the formation of bubbles in the adhesive layers 24 and 26 formed by the pressure-sensitive adhesive can be prevented.

[0033] Then, if Figure 4 As shown in (C) in the figure, the manufacturing method includes a step of bonding the support frame 20 and the diaphragms 16, 18 to each other. In this step, a compressive force is applied to the support frame 20 and the diaphragms 16, 18 that are in contact with each other via the adhesive layers 24, 26. As a result, the anode side diaphragm 16 is bonded to the support frame 20 via the first adhesive layer 24, and the cathode side diaphragm 18 is bonded to the support frame 20 via the second adhesive layer 26. In addition, the method of bringing the diaphragms 16, 18 close to the support frame 20 and the method of applying a compressive force to the support frame 20 and the diaphragms 16, 18 are not particularly limited. As an example, a punching device or the like can be used in these steps.

[0034] Figure 5 (A) to (C) in FIG. 2 represent several variations of the adhesive layers 24 and 26. Figure 5 As shown in (A) in FIG. 1 , in a cross section perpendicular to the longitudinal direction of the sealing line, the adhesive layers 24 and 26 formed on the support frame 20 may have a surface that is partially or entirely curved into a concave shape. Alternatively, Figure 5 As shown in (B) and (C) in FIG. 1 , in a cross section perpendicular to the longitudinal direction of the sealing 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 end in the width direction. In this case, the two adhesive layers 24 and 26 may have a shape that is asymmetric to each other (see FIG. 1 ). Figure 5 (B) in the figure), or may have a shape that is symmetrical to each other (see Figure 5 (C) in the.

[0035] As described above, the adhesive layers 24 and 26 are formed to include the opening 22 of the support frame 20 and the respective manifold holes 28a-28f. In this case, there are sections adjacent to the manifold holes 28a-28f and sections not adjacent to the manifold holes 28a-28f in the adhesive layers 24 and 26. In the vicinity of the manifold holes 28a-28f, the pressure acting on the adhesive layers 24 and 26 is relatively high. Therefore, in the sections adjacent to the manifold holes 28a-28f, the width and / or thickness of the first adhesive layer 24 can be increased compared to the sections not adjacent to the manifold holes 28a-28f.

[0036] In the above-mentioned embodiment and modification, each of the two adhesive layers 24 and 26 has a shape with a thickness varying in the width direction. In contrast, in other embodiments, only one of the two adhesive layers 24 and 26 may have a shape with a thickness varying in the width direction. That is, the other of the two adhesive layers 24 and 26 may have a shape with a constant thickness in the width direction.

[0037] In the above-mentioned embodiment and modification, each of the two adhesive layers 24 and 26 has a shape in which the thickness varies in the width direction. Figure 6 As shown in (A) and (B) in FIG. 1 , in another embodiment, the above-mentioned profile provided on the surface of the adhesive layer 24, 26 may be provided on the surface of the diaphragm 16, 18 in contact with the adhesive layer 24, 26. That is, the surface of the diaphragm 16, 18 may be provided with a protrusion 32 protruding toward the adhesive layer 24, 26, respectively.

[0038] In this case, the protrusion amount of the protrusion 32 is maximum at a specific one position Q1 or Q2 and may be monotonically decreased as it moves away from the one position Q1 or Q2 in the width direction of the seal line (ie, the X direction).

[0039] With such a configuration, when the anode-side separator 16 gradually approaches the first adhesive layer 24, in a cross section perpendicular to the longitudinal direction of the sealing line, the distance between the surface of the first adhesive layer 24 and the surface of the anode-side separator 16 opposite to the surface is smallest at the one position Q1, and increases monotonically as it moves away from the one position Q1 in the width direction of the sealing line (i.e., the X direction). Thus, the formation of bubbles in the adhesive layers 24 and 26 can be suppressed.

[0040] In this embodiment, the support frame 20 and the diaphragms 16 and 18 are bonded to each other by means of adhesive layers 24 and 26 formed of a pressure-sensitive adhesive. Alternatively or in addition, the anode-side diaphragm 16 of the fuel cell 12 and the cathode-side diaphragm 18 of another adjacent fuel cell 12 may be bonded to each other by means of adhesive layers 24 and 26 formed of a pressure-sensitive adhesive.

[0041] In this case, if Figure 7 As shown in (A) of FIG. 1 , the manufacturing method includes a step of forming a third adhesive layer 34 on the surface of the anode side diaphragm 16. In this step, a pressure-sensitive adhesive is applied to the anode side diaphragm 16 along a predetermined sealing line. The third adhesive layer 34, like the above-mentioned adhesive layers 24 and 26, only needs to have a shape in which the thickness varies in the width direction (see FIG. 1 ). Figure 4 , Figure 5 ).

[0042] Next, if Figure 7 As shown in (B) in the figure, the manufacturing method includes a step of bringing the cathode side diaphragm 18 of the other fuel cell 12 closer to the surface of the anode side diaphragm 16. In this step, the cathode side diaphragm 18 is gradually brought closer to the anode side diaphragm 16 until it contacts the third adhesive layer 34 on the anode side diaphragm 16. As a result, the cathode side diaphragm 18 contacts the third adhesive layer 34 on the anode side diaphragm 16 and is positioned. In addition, this step can also be combined with the above-mentioned Figure 4 The steps (B) are carried out simultaneously.

[0043] The third adhesive layer 34 has a shape in which the thickness varies in the width direction of the seal line (i.e., the X direction). Therefore, when the cathode side separator 18 gradually approaches the third adhesive layer 34, in a cross section perpendicular to the longitudinal direction of the seal line, the distance between the surface of the third adhesive layer 34 and the surface of the cathode side separator 18 opposite to the surface is the smallest at a specific position R1, and increases monotonically as it moves away from the position R1 in the width direction of the seal line. Thus, even in the third adhesive layer 34 formed of a pressure-sensitive adhesive, the formation of bubbles can be suppressed.

[0044] Next, if Figure 7 As shown in (C) in FIG. 1 , the manufacturing method includes a step of bonding the two diaphragms 16 and 18 to each other. In this step, a compressive force is applied to the two diaphragms 16 and 18 that are in contact with each other through the third adhesive layer 34. As a result, the two diaphragms 16 and 18 are bonded to each other through the third adhesive layer 34. As a result, the two diaphragms 16 and 18 are sealed by the third adhesive layer 34, and the gasket required between the two diaphragms 16 and 18 can be omitted. In addition, this step can also be combined with the above-mentioned Figure 4 The steps (C) are carried out simultaneously.

[0045] In addition, the anode side separator 16 in this embodiment 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 modified example, the third adhesive layer 34 may be formed on the cathode side separator 18 instead of the anode side separator 16.

[0046] Several specific examples have been described in detail above, but these are merely illustrative and do not limit the scope of protection claimed in this application. The technology described in the scope of protection claimed in this application includes technologies obtained by variously deforming and changing the specific examples illustrated above. The technical elements described in this specification or the drawings can exert the usefulness of the technology alone or in combination.

[0047] Description of reference numerals:

[0048] 10 ... fuel cell; 12 ... fuel cell cell; 14 ... MEA; 16, 18 ... diaphragm; 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, wherein: have: A step of applying a pressure-sensitive adhesive along a predetermined sealing line on the surface of a support frame supporting the membrane electrode assembly to form an adhesive layer; a step of bringing the diaphragm closer to the surface of the support frame until the diaphragm comes into contact with the adhesive layer formed on the support frame; as well as a step of applying a compressive force to the support frame and the diaphragm which are in contact with each other via the adhesive layer to bond the support frame and the diaphragm to each other, In the approaching process, in a cross section perpendicular to the length direction of the sealing line, the distance between the surface of the adhesive layer and the surface of the diaphragm opposite to the surface is smallest at a specific position, and increases monotonically as it moves away from the position in the width direction of the sealing line.

2. The method for manufacturing a fuel cell according to claim 1, wherein: In the process of forming the adhesive layer, the adhesive is applied in such a manner that the thickness of the adhesive layer is maximum at one position in the cross section perpendicular to the length direction of the sealing line and decreases monotonically as it moves away from the one position in the width direction of the sealing 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 so that the adhesive layer has a bilaterally symmetrical shape in the cross section perpendicular to the longitudinal direction of the seal line.

4. The method for manufacturing a fuel cell according to any one of claims 1 to 3, wherein: In the approaching process, in the cross-section perpendicular to the length direction of the sealing line, the surface of the diaphragm opposite to the adhesive layer protrudes toward the adhesive layer, and the protrusion amount is maximum at the one position and decreases monotonically as it moves away from the one position in the width direction of the sealing line.

5. A method for manufacturing a fuel cell, wherein: have: A step of applying a pressure-sensitive adhesive along a predetermined sealing line on the surface of a first diaphragm constituting a fuel cell to form an adhesive layer; a step of bringing a second separator constituting another fuel cell close to the surface of the first separator until it comes into contact with the adhesive layer formed on the first separator; as well as a step of applying a compressive force to the first diaphragm and the second diaphragm that are in contact with each other via the adhesive layer to bond the first diaphragm and the second diaphragm to each other, In the approaching process, in a section perpendicular to the length direction of the sealing line, the distance between the surface of the adhesive layer and the surface of the second diaphragm opposite to the surface is smallest at a specific position and increases monotonically as it moves away from the position in the width direction of the sealing line.

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